SHEET FEEDING APPARATUS AND IMAGE FORMING APPARATUS

Abstract

A sheet feeding apparatus configured to feed a sheet includes a sheet support portion, a feeding portion, a sheet support detection portion, a separation portion, and a control portion configured to selectively execute a first mode and a second mode, wherein in a case where a first type is set as a sheet type of the sheets in a state where the first mode is selected, the control portion starts air blowing by the separation portion upon detection that the sheets are supported on the sheet support portion, and wherein in a case where the sheet type setting operation is executed upon detection that the sheets are supported on the sheet support portion and the first type is set as the sheet type in a state where the second mode is selected, the control portion starts air blowing by the separation portion.

Description

BACKGROUND

Field

The present disclosure relates to a sheet feeding apparatus including a separation portion that blows air to a plurality of sheets manually fed and supported on a support portion to separate the sheets, and an image forming apparatus including the sheet feeding apparatus.

Description of the Related Art

Some image forming apparatuses, including a copying machine, a facsimile machine, and a printer, are provided with a manual feed tray for feeding various types of sheets as a sheet feeding apparatus configured to feed sheets to an image forming portion to form an image on each sheet. In recent years, with the increasing demand for forming an image on various types of sheets, sheets with a smooth surface, such as coated paper, have been used in some cases.

If a bundle of such sheets with a smooth surface is set on the manual feed tray described above, there is a possibility that the sheets cannot be separated due to high adhesion between the sheets, which may lead to a feeding failure. To address the issue, Japanese Patent Application Laid-Open No. 2006-256819 discusses a technique for performing a so-called air separation operation in which air is blown to a bundle of sheets set on a manual feed tray so that the sheets are lifted and separated from each other.

However, when sheets are fed while air is blown to the bundle of sheets and the sheets are lifted as discussed in Japanese Patent Application Laid-Open No. 2006-256819, edges of each sheet are likely to hang down and curl. Therefore, for example, even if the position of each sheet in its width direction is regulated by a side regulating plate, there is an issue that rotation of the sheet is likely to occur and accordingly, skew of the sheet is likely to occur.

SUMMARY

The present disclosure is directed to providing a sheet feeding apparatus configured to separate sheets by blowing air to the sheets while reducing skew of each sheet, and an image forming apparatus including the sheet feeding apparatus.

According to some embodiments, a sheet feeding apparatus configured to feed a sheet includes a sheet support portion located at a side surface of the sheet feeding apparatus and configured to support a plurality of sheets, a feeding portion configured to feed the plurality of sheets supported on the sheet support portion one by one, a sheet support detection portion configured to detect that sheets are supported on the sheet support portion, a separation portion configured to separate the plurality of sheets supported on the sheet support portion by blowing air to the plurality of sheets, and a control portion configured to selectively execute a first mode in which a sheet type setting operation for the sheets supported on the sheet support portion is executed in advance and a second mode in which the sheet type setting operation is executable upon detection that the sheets are supported on the support portion by the sheet support detection portion, wherein in a case where a first type is set as a sheet type of the sheets in a state where the first mode is selected, the control portion starts air blowing by the separation portion upon detection that the sheets are supported on the sheet support portion by the sheet support detection portion, and wherein in a case where the sheet type setting operation is executed upon detection that the sheets are supported on the sheet support portion by the sheet support detection portion and the first type is set as the sheet type in a state where the second mode is selected, the control portion starts air blowing by the separation portion.

Further features of the present disclosure will become apparent from the following description of exemplary embodiments with reference to the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view illustrating a schematic configuration of an image forming system according to an exemplary embodiment of the present disclosure.

FIG. 2 is a block diagram illustrating a control system of the image forming system according to the exemplary embodiment.

FIG. 3 is a schematic view illustrating a configuration of a manual feed portion according to the exemplary embodiment.

FIG. 4 is a schematic view illustrating a state where an air blowing operation is performed by the manual feed portion according to the exemplary embodiment.

FIG. 5 is a flowchart illustrating a sheet information mode setting process according to the exemplary embodiment.

FIG. 6 is a flowchart illustrating the sheet information setting process when a fixed mode is set as a sheet information mode according to the exemplary embodiment.

FIG. 7A is an explanatory diagram illustrating a sheet feed destination selection screen and an operation unit, FIG. 7B is an explanatory diagram illustrating a manual feed tray function settings screen and the operation unit, FIG. 7C is an explanatory diagram illustrating a sheet information mode selection screen and the operation unit, FIG. 7D is an explanatory diagram illustrating a sheet size setting screen, and FIG. 7E is an explanatory diagram illustrating a sheet type selection screen.

FIG. 8 is a flowchart illustrating a sheet presence/absence determination process according to the exemplary embodiment.

FIG. 9 is a flowchart illustrating an air blowing operation process according to the exemplary embodiment.

FIG. 10 is a flowchart illustrating an air blowing execution flag setting process when the fixed mode is set as the sheet information mode according to the exemplary embodiment.

FIG. 11 is a table storing a relationship between a paper type and a need for air blowing according to the exemplary embodiment.

FIG. 12 is a flowchart illustrating the sheet information setting process when a manual mode is set as the sheet information mode according to the exemplary embodiment.

FIG. 13A is an explanatory diagram illustrating a home screen and the operation unit, FIG. 13B is an explanatory diagram illustrating a sheet feed cassette setting screen, FIG. 13C is an explanatory diagram illustrating a sheet size setting screen, and FIG. 13D is an explanatory diagram illustrating a sheet type setting screen.

FIG. 14 is a flowchart illustrating a printing operation process according to the exemplary embodiment.

FIG. 15 is a flowchart illustrating a process of an air blowing operation and a feeding operation according to a reference example.

FIG. 16 is an explanatory diagram illustrating a state of each sheet when a feeding operation is performed while air is blown to sheets in the reference example.

DESCRIPTION OF THE EMBODIMENTS

Various exemplary embodiments, features, and aspects of the present disclosure will be described in detail below with reference to the drawings. An image forming apparatus 201 including a manual feed portion 235 as a sheet feeding apparatus and an image forming system 600 including a sheet feed cassette 800 that is connected to the image forming apparatus 201 will now be described with reference to FIG. 1. FIG. 1 is a schematic view illustrating a schematic configuration of the image forming system 600 according to an exemplary embodiment of the present disclosure.

[Schematic Configuration of Image Forming System]

As illustrated in FIG. 1, the image forming system 600 includes the image forming apparatus 201 including the manual feed portion 235, and the sheet feed cassette 800 that is connected to the image forming apparatus 201. The sheet feed cassette 800 is connected to the right side of the image forming apparatus 201 in FIG. 1 and is configured to feed sheets S to the image forming apparatus 201. The manual feed portion 235 is also configured to feed sheets S to the image forming apparatus 201.

[Schematic Configuration of Image Forming Apparatus]

As illustrated in FIG. 1, the image forming apparatus 201 includes an apparatus main body 201A including an image forming portion 201B for forming an image on each sheet S. An image reading apparatus 202 that is placed substantially horizontally is located above the apparatus main body 201A. A discharge space V for discharging the sheets S is formed between the image reading apparatus 202 and the apparatus main body 201A. An operation unit 700 that is a user interface (UI) constituted by a touch panel or the like configured to display a screen is located above the apparatus main body 201A.

The image forming portion 201B is a four-drum full-color system. The image forming portion 201B includes a laser scanner 210 and four process cartridges 211 that form toner images of four colors of yellow (Y), magenta (M), cyan (C), and black (K), respectively. Each process cartridge 211 includes a photosensitive drum 212, a charging device 213 as a charging unit, and a developing device 214 as a developing unit. The image forming portion 201B also includes an intermediate transfer unit 201C, which is located above the process cartridges 211, and a fixing unit 201E. A toner cartridge 215 for supplying toner to the developing device 214 is provided above the intermediate transfer unit 201C.

The intermediate transfer unit 201C includes an intermediate transfer belt 216 that is wound around a driving roller 216a and a tension roller 216b. A primary transfer roller 219 that is in contact with the intermediate transfer belt 216 at a position opposed to the photosensitive drum 212 is provided on an inner side of the intermediate transfer belt 216. In this case, the intermediate transfer belt 216 is rotated in a direction indicated by an arrow by the driving roller 216a that is driven by a driving portion.

The toner images of the respective colors having a negative polarity on the photosensitive drum 212 are sequentially transferred in a superimposed manner onto the intermediate transfer belt 216 by the primary transfer roller 219. A secondary transfer roller 217 that transfers the color images formed on the intermediate transfer belt 216 onto a sheet S is provided at a position opposed to the driving roller 216a of the intermediate transfer unit 201C. A secondary transfer portion 201D is formed between the intermediate transfer belt 216 and the secondary transfer roller 217. The fixing unit 201E including a pressure roller 220a and a heating roller 220b is located above the secondary transfer roller 217. A first discharge roller pair 225a, a second discharge roller pair 225b, and a double-side reverse portion 201F are located above the fixing unit 201E. The double-side reverse portion 201F includes a reverse roller pair 222 configured to rotate in forward and reverse directions, and a reconveyance path R for reconveying the sheet S having an image formed on one surface thereof to the image forming portion 201B.

A plurality of sheet feed units 230 for feeding sheets S set therein to the image forming portion 201B is provided below the apparatus main body 201A. Each of the sheet feed units 230 includes a feed cassette 1 that stores a plurality of sheets S (a bundle of sheets), and a sheet feeding portion 6 serving as a feeding portion for feeding the sheets S stored in the feed cassette 1. The sheet feeding portion 6 includes a pickup roller 2, a feed roller 3, and a retard roller 4. The feed roller 3 and the retard roller 4 each serve as a separation portion that separates the sheets S that are fed in an overlapped state from the pickup roller 2.

The sheet feed cassette 800 that delivers the set sheets S to the image forming portion 201B is provided below the manual feed portion 235 at a right side surface of the apparatus main body 201A in FIG. 1. The sheet feed cassette 800 includes a sheet feeding portion 806, like the sheet feed units 230. Specifically, the sheet feeding portion 806 includes a pickup roller 801, a feed roller 802, and a retard roller 803. The feed roller 802 and the retard roller 803 each serve as a separation portion that separates the sheets S that are fed in an overlapped state from the pickup roller 801. A drawing roller pair 804 is provided downstream of the sheet feeding portion 806 in a sheet conveyance direction.

The manual feed portion 235 that feeds each of the plurality of sheets S (a bundle of sheets) set manually to the image forming portion 201B is provided at a right side surface of the apparatus main body 201A in FIG. 1. The manual feed portion 235 includes a manual feed tray 236 that allows a user to manually set and feed sheets S. The manual feed tray 236 is rotatable with respect to the apparatus main body 201A and is movable in an opening/closing direction. In other words, the manual feed tray 236 can be switched between an open state where the manual feed tray 236 is opened with respect to the apparatus main body 201A and a closed state where the manual feed tray 236 is closed with respect to the apparatus main body 201A. That is, the manual feed tray 236 is configured to support the sheets S in the open state.

The manual feed portion 235 also includes a sheet feeding portion 506, like the sheet feed units 230. Specifically, the sheet feeding portion 506 includes a pickup roller 501, a feed roller 502, and a retard roller 503. The feed roller 502 and the retard roller 503 each serve as a separation portion that separates the sheets S that are fed in an overlapped state from the pickup roller 501. A drawing roller pair 504 is provided downstream of the sheet feeding portion 506 in the sheet conveyance direction.

[Operation of Image Forming Apparatus]

Next, an image forming operation to be performed by the image forming apparatus 201 will be described. First, for example, when image information on a document is read by the image reading apparatus 202, image processing is performed on the image information. After that, the image information is converted into an electric signal, and the electric signal is transmitted to the laser scanner 210 of the image forming portion 201B. This image information may be transmitted from a host apparatus 1500 (see FIG. 2) or an external computer via a network.

The surface of the image forming portion 201B is uniformly charged with a predetermined polarity and potential by the charging device 213, and the surfaces of the photosensitive drums 212 are sequentially exposed to laser light. Thus, electrostatic latent images of yellow, magenta, cyan, and black are sequentially formed on the surfaces of the photosensitive drums 212 of the process cartridges 211.

After that, the electrostatic latent images are developed and visualized with toner of each color, and the toner images of the respective colors formed on the surfaces of the photosensitive drums 212 are sequentially transferred in a superimposed manner onto the intermediate transfer belt 216 by primary transfer bias applied to the primary transfer roller 219. Thus, the toner images are formed on the intermediate transfer belt 216.

On the other hand, the sheet S fed from any of the sheet feed units 230 (or the manual feed portion 235 or the sheet feed cassette 800) is conveyed to a registration roller pair 240 composed of a driving roller and a driven roller. At this time, driving of the registration roller pair 240 is stopped, and a leading edge of the sheet S is brought into contact with the registration roller pair 240. This allows the leading edge of the sheet S to be aligned by the registration roller pair 240.

After that, the sheet S is continuously conveyed by the feed roller 3 (or the feed roller 502 or the feed roller 802) or the like, so that a warp (loop) is formed in the sheet S. Then, the registration roller pair 240 is driven in synchronized time with the arrival of the toner images on the intermediate transfer belt 216. This enables the registration roller pair 240 to correct skew of the sheet S, and the skew-corrected sheet S is conveyed by the registration roller pair 240 the secondary transfer portion 201D.

Next, in the secondary transfer portion 201D, the toner images are collectively transferred onto the sheet S by secondary transfer bias applied to the secondary transfer roller 217. The sheet S to which the toner images are transferred is conveyed to the fixing unit 201E. The fixing unit 201E applies heat and pressure to the sheet S, and the toner images of the respective colors are melted, color-mixed and then fixed as a color image onto the sheet S.

After that, the sheet S to which the images are fixed is discharged to the discharge space V by the first discharge roller pair 225a or the second discharge roller pair 225b provided downstream of the fixing unit 201E. Then, the sheet S is stacked on a stacking portion 223 formed on a bottom surface of the discharge space V. In the case of forming images on both surfaces of the sheet S, after the images are fixed onto the sheet S, the sheet S is conveyed to the reconveyance path R by the reverse roller pair 222 and then conveyed to the secondary transfer portion 201D, again.

[Configuration of Manual Feed Portion]

Next, the manual feed portion 235 serving as the sheet feeding apparatus will be described in detail with reference to FIGS. 1 and 3. FIG. 3 is a schematic view illustrating a configuration of the manual feed portion 235 according to the present exemplary embodiment.

As illustrated in FIGS. 1 and 3, the manual feed portion 235 includes the manual feed tray 236 as a support portion, and the sheet feeding portion 506 as a feeding portion that feeds the sheets S and separates the sheets S that are fed in an overlapped state. The sheet feeding portion 506 also includes the pickup roller 501 as a feed roller that comes into contact with the uppermost sheet S of the bundle of sheets S and feeds the uppermost sheet S.

The sheet feeding portion 506 also includes the feed roller 502 and the retard roller 503 as the separation portion that separates the sheets S fed from the pickup roller 501.

In the manual feed portion 235, the drawing roller pair 504 for drawing out the sheet S from the feed roller 502 and conveying the sheet S to the image forming apparatus 201 is provided downstream of the feed roller 502 in a sheet feeding direction U. A feed sensor 505 serving as a sheet detection portion is located between the feed roller 502 and the drawing roller pair 504 in the sheet feeding direction U, i.e., downstream of the sheet feeding portion 506 in the sheet feeding direction U. The feed sensor 505 outputs a signal based on the presence or absence of the sheet S to detect passage of the sheet S.

As illustrated in FIG. 3, the manual feed tray 236 is provided with a manual feed tray table 515 and a lifter plate 514 serving as a support portion on which a bundle of a plurality of sheets S is stacked and supported. The lifter plate 514 is provided with a sheet presence/absence detection sensor 401 as a sheet support detection portion for detecting that the sheet S is supported on the manual feed tray 236. The position of the lifter plate 514 in a height direction is controlled based on the amount of stacked sheets S by a lifting mechanism (not illustrated).

As illustrated in FIG. 3, the manual feed tray 236 is provided with side edge regulating plates 511 and 512 that regulate the position of the sheet S supported on the manual feed tray 236 in a width direction W that is orthogonal to the sheet feeding direction U. The side edge regulating plates 511 and 512 regulate the positions in the width direction W of edges (sheet side edges) of the sheet S set on the lifter plate 514. These side edge regulating plates 511 and 512 are provided with air blowing portions 511A and 512A, respectively, as separation portions. The air blowing portion 511A includes a fan 511b to be driven by a fan motor 511M (see FIG. 2), and a duct 511a for blowing air from a side of the bundle of sheets by guiding air blown from the fan 511b to pass through the side edge regulating plate 511. Similarly, the air blowing portion 512A includes a fan 512b to be driven by a fan motor 512M (see FIG. 2), and a duct 512a for blowing air from a side of the bundle of sheets by guiding air blown from the fan 512b to pass through the side edge regulating plate 512. The side edge regulating plates 511 and 512 are also provided with lift suppressing plates 511c and 512c, respectively, in the vicinity of openings of the ducts 511a and 512a to prevent the sheet S from lifting up beyond the heights of the side edge regulating plates 511 and 512 when air is blown toward the sheets S.

[Configuration of Control System of Image Forming System]

Next, a configuration of a control system of the image forming system 600 will be described with reference to FIG. 2. FIG. 2 is a block diagram illustrating the control system of the image forming system 600 according to the present exemplary embodiment.

A control unit 100 according to the present exemplary embodiment is included in, for example, the image forming apparatus 201, and includes a central processing unit (CPU) 101, a read-only memory (ROM) 102, a random access memory (RAM) 103, and an electrically erasable programmable read-only memory (EEPROM) 104. The control unit 100 is a control unit that may include one or more processors, circuitry, or combinations thereof, and controls the image forming apparatus 201, the sheet feed cassette 800, and the manual feed portion 235 in an integrated manner. The control unit 100 is connected to the host apparatus 1500 and the operation unit 700 to perform signal processing, sequence control processing, and the like for various processing devices, while exchanging information with the host apparatus 1500 and the operation unit 700. The host apparatus 1500 is an external apparatus, such as a personal computer, an image scanner, or a facsimile. The control unit 100 is also connected to a fan control unit 510 for controlling driving of the fan motors 511M and 512M, a feed motor 520 for driving the pickup roller 501, and the feed sensor 505. The control unit 100 is also connected to a conveyance motor 521 for driving the drawing roller pair 504 and the like, the sheet presence/absence detection sensor 401, and the like.

[Air Blowing Operation]

Next, an operation to be performed when air is blown from the sides of a bundle of sheets by the air blowing portions 511A and 512A will be described with reference to FIG. 4. FIG. 4 is a schematic view illustrating a state where an air blowing operation is performed by the manual feed portion 235 according to the present exemplary embodiment.

As illustrated in FIG. 4, when the control unit 100 starts the air blowing operation, the fans 511b and 512b of the air blowing portions 511A and 512A blow air toward the side surfaces of the bundle of sheets as indicated by arrows A1 and A2 through the ducts 511a and 512a, respectively. As a result, several to several tens of sheets S on the upper part of the bundle of sheets are separated from the rest of the bundle and each lifted up, and the uppermost sheet S comes into contact with the lift suppressing plates 511c and 512c, thereby regulating the lift of the sheets S separated from the bundle. This makes it possible to reduce adhesion between the sheets S and to feed the sheets S having smooth surface properties, such as coated paper, with a conveyance force of the pickup roller 501.

[Issues Related to Sheet Feeding while Blowing Air to Sheets]

Issues related to feeding of the sheets S while blowing air to the sheets S will be described with reference to FIGS. 15 and 16. FIG. 15 is a flowchart illustrating a process of an air blowing operation and a feeding operation according to a reference example. FIG. 16 is an explanatory diagram illustrating a state where the sheets S are fed while air is blown to the sheets S in the reference example.

A general control operation for feeding the sheets S while separating the sheets S by blowing air to a bundle a plurality of sheets S will now be described with reference to FIG. 15. As illustrated in FIG. 15, in step S101, a control operation for sheet feeding is started in response to an instruction, such as a print job start instruction. In step S102, an operation for blowing air to the bundle of sheets is started. The operation of blowing air is continuously performed so that the sheets S can be separated and lifted before a predetermined period (e.g., 10 seconds) has elapsed from the start of air blowing (NO in step S103). After the lapse of the predetermined period from the start of air blowing (YES in step S103), the processing proceeds to step S104. In step S104, the feeding operation for feeding the sheets S is performed by the pickup roller 501. The feeding operation is repeatedly performed based on a print job instruction before a number of sheets S to be fed to the image forming portion 201B is reached (NO in step S105). If the number of sheets S is reached (YES in step S105), the processing proceeds to step S106. In step S106, the air blowing operation is stopped. In step S107, this control operation ends.

Due to a relationship with other components in terms of design, for example, as illustrated in FIG. 16, a center C1 of the pickup roller 501 and a center C2 of the feed roller 502 can be shifted from each other by a distance X in the width direction W that is orthogonal to the sheet feeding direction U. In this case, if a conveyance load occurs in the vicinity of the pickup roller 501 during conveyance of an uppermost sheet S1 by the feed roller 502 due to a difference in conveyance speed or the like, a turning force in a counterclockwise direction is generated on the sheet S1.

Accordingly, the sheet S1 is fed while being rotated, so that skew of the sheet S1 occurs.

In this case, even when the turning force is generated on the sheet S1, in general, side edges of the sheet S1 come into contact with the side edge regulating plates 511 and 512, and skew of the sheet S1 can be suppressed due to the stiffness of the sheet S1. However, since the sheet S1 is lifted by air blown from the air blowing portions 511A and 512A, the sheet S1 is more likely to be warped as illustrated in FIG. 16. Therefore, the effect of suppressing skew of the sheet S1 by the side edge regulating plates 511 and 512 can be decreased and the amount of skew of the sheet S1 can be increased. On the other hand, if the air blowing operation is not started at an appropriate timing, it takes time to start printing, which has an adverse effect on so-called First Copy Out Time (FCOT). Therefore, in the present exemplary embodiment, as described below, the air blowing operation is not performed during sheet feeding and the air blowing operation is started at an appropriate timing when the sheet S is set on the manual feed portion 235. A control operation to be performed according to the present exemplary embodiment to address the issues described above will be described in detail below.

[Sheet Information Mode Setting]

A sheet information mode for setting information (sheet type) about each sheet S set and supported on the manual feed tray 236 in the image forming apparatus 201 according to the present exemplary embodiment includes two modes, i.e., a fixed mode as a first mode and a manual mode as a second mode. The control unit 100 is configured to selectively execute the fixed mode and the manual mode by selecting one of the fixed mode and the manual mode in a sheet information mode setting process.

The sheet information mode setting process will be described below with reference to FIGS. 5 and 7. FIG. 5 is a flowchart illustrating the sheet information mode setting process according to the present exemplary embodiment. FIG. 7A is an explanatory diagram illustrating a sheet feed destination selection screen and the operation unit 700. FIG. 7B is an explanatory diagram illustrating a manual feed tray function settings screen and the operation unit 700. FIG. 7C is an explanatory diagram illustrating a sheet information mode selection screen and the operation unit 700. FIG. 7D is an explanatory diagram illustrating a sheet size setting screen.

FIG. 7E is an explanatory diagram illustrating a sheet type selection screen.

The fixed mode is a mode in which the sheet information (i.e., sheet type) setting process is executed in advance regardless of whether the sheet S is set on the manual feed tray 236, i.e., regardless of whether the sheet S is present on the manual feed tray 236. The manual mode is a mode in which a user can set sheet information (sheet type) every time the sheet S is set on the manual feed tray 236, i.e., every time the sheet presence/absence detection sensor 401 detects a state where “paper is present” (sheet is present). The sheet information set as described above is used for various processes such as a sheet feeding process, a sheet conveyance process, and an image forming process. Particularly, in the present exemplary embodiment, the sheet information is used to determine whether to execute an air separation operation.

As illustrated in FIG. 7A, the operation unit 700 is provided with a start key 702 for starting the image forming operation, a stop key 703 for stopping the image forming operation, and numeric keys 704 to 712 and 714 for making numerical settings and the like. The operation unit 700 is also provided with an identification (ID) key 713, a clear key 715, a reset key 716, and a function settings key 730. A display unit 720 in which a touch panel is formed is located at an upper portion, and software keys can be created on a screen.

The sheet information mode is set using the operation unit 700. As illustrated in FIG. 7A, when the function settings key 730 on the operation unit 700 is pressed, a function settings menu is displayed on the display unit 720. In this case, when a manual feed tray button 815 is pressed, as illustrated in FIG. 7B, the manual feed tray function settings screen is displayed on the display unit 720, and a sheet information mode setting button 821 is also displayed. Then, when the sheet information mode setting button 821 displayed on the display unit 720 is pressed, as illustrated in FIG. 7C, a sheet information mode screen is displayed on the display unit 720, and a manual mode button 831 and a fixed mode button 832 are also displayed. When a back button 816 is pressed in a state where the function settings menu is displayed on the display unit 720, the screen returns to a home screen. When a cancel button 822 is pressed in a state where the manual feed tray function settings screen is displayed on the display unit 720, the screen returns to the function settings menu. When a cancel button 834 is pressed in a state where the sheet information mode screen is displayed on the display unit 720, the screen returns to the manual feed tray function settings screen.

The sheet information mode setting process to be executed by the control unit 100 illustrated in FIG. 5 will now be described. As illustrated in FIG. 5, when the sheet information mode setting process is started, in step S131, the control unit 100 determines whether mode selection has ended. Specifically, the control unit 100 monitors pressing of either one of the manual mode button 831 and the fixed mode button 832 displayed on the display unit 720 illustrated in FIG. 7C. When one of the manual mode button 831 and the fixed mode button 832 is pressed (YES in step S131), the processing proceeds to step S132. In step S132, it is determined whether the manual mode is selected (selected mode). If the manual mode button 831 illustrated in FIG. 7C is selected and an OK button 833 is pressed (YES in step S132), the processing proceeds to step S133. In step S133, the manual mode is set as the sheet information mode. In step S136, the value for the manual mode is stored in the EEPROM 104, and then the sheet information mode setting process ends. If the fixed mode button 832 illustrated in FIG. 7C is selected and the OK button 833 is pressed (NO in step S132), the processing proceeds to step S134. In step S134, a fixed mode sheet information setting process to be described below is performed. In step S135, the fixed mode is set as the sheet information mode. In step S136, the value for the fixed mode is stored in the EEPROM 104, and then the sheet information mode setting process ends.

[Sheet Information Setting Process when Fixed Mode is Selected]

Next, a sheet information setting process to be executed by the control unit 100 when the fixed mode is selected will be described with reference to FIGS. 6 and 7. FIG. 6 is a flowchart illustrating the sheet information setting process to be executed when the fixed mode is set as the sheet information mode according to the present exemplary embodiment. A sheet information setting process to be executed when the manual mode is selected will be described in detail below in a description of a process for an air blowing operation to be described below.

In the sheet information mode setting process described above, when the fixed mode button 832 is selected and the OK button 833 is selected, the fixed mode is selected as the sheet information mode (NO in step S132), the control unit 100 starts the fixed mode sheet information setting process in step S134 illustrated in FIG. 6. Then, in step S141, the control unit 100 executes the sheet size setting process, and causes the screen on the display unit 720 to transition to the sheet size setting screen illustrated in FIG. 7D. Next, the control unit 100 waits until the sheet size setting process ends (NO in step S142), i.e., waits until a button indicating a sheet size is selected by the user on the sheet size setting screen and a next button is pressed. FIG. 7D illustrates a state where “A3-size” is selected.

If the sheet size is selected and the sheet size setting process has ended as described above (YES in step S142), the processing proceeds to step S143. In step S143, the control unit 100 executes a sheet type setting process and causes the screen on the display unit 720 to transition to a sheet type setting screen illustrated in FIG. 7E. Next, the control unit 100 waits until the sheet type setting process ends (NO in step S144), i.e., waits until a button indicating a sheet type is selected by the user and an OK button is pressed on the sheet type setting screen. FIG. 7E illustrates a state where “coated paper 1” is selected.

If the sheet type is selected and the OK button is pressed (YES in step S144), the processing proceeds to step S145. In step S145, the control unit 100 stores values set for the manual feed tray 236 as fixed information in the EEPROM 104. In this case, the values to be stored in the EEPROM 104 include values for the fixed mode sheet size setting and the fixed mode sheet type setting selected as described above.

Then, the control unit 100 causes the screen on the display unit 720 to transition to, for example, a sheet feed destination selection screen illustrated in FIG. 7A. Thus, the sheet information setting process to be executed when the fixed mode is selected ends.

[Sheet Presence/Absence Determination Process]

Next, a sheet presence/absence determination process according to the present exemplary embodiment will be described with reference to FIG. 8. FIG. 8 is a flowchart illustrating the sheet presence/absence determination process according to the present exemplary embodiment. This sheet presence/absence determination process is a process in which the control unit 100 determines whether there is a sheet S stacked on the lifter plate 514 of the manual feed tray 236. This flow of the sheet presence/absence determination process is constantly executed by the control unit 100 during activation of the image forming apparatus 201.

Specifically, in step S801, the sheet presence/absence detection sensor 401 located on the manual feed tray 236 determines whether the sheet S is stacked on the manual feed tray 236, to thereby monitor the presence or absence of the sheet S. For example, when the sheet S is present, the sheet presence/absence detection sensor 401 is ON, and when no sheet S is present, the sheet presence/absence detection sensor 401 is OFF. If the sheet presence/absence detection sensor 401 is OFF, the control unit 100 repeatedly performs this process until the sheet presence/absence detection sensor 401 is turned ON (paper is present) (NO in step S801), i.e., waits until the sheet S is stacked on the manual feed tray 236.

After that, when the sheet S is stacked on the manual feed tray 236, the sheet presence/absence detection sensor 401 is turned ON (YES in step S801), and the processing proceeds to step S802. In step S802, the sheet information mode stored in the EEPROM 104 is copied to the RAM 103 to refer to the sheet information mode set as described above.

Next, in step S803, the sheet information mode is determined using the value corresponding to the sheet information mode copied to the RAM 103. If the manual mode is set as the sheet information mode (YES in step S803), the processing proceeds to step S804. In step S804, the sheet information held in the RAM 103 is cleared. On the other hand, if the fixed mode is set as the sheet information mode (NO in step S803), the fixed mode sheet information is held in the RAM 103, and thus the sheet information is not cleared.

Next, in step S805, the control unit 100 temporarily sets (initializes) an air blowing execution flag to OFF when the sheet presence/absence detection sensor 401 is changed from the OFF state to the ON state, and stores information about the air blowing execution flag in the RAM 103. In step S806, a manual feed tray sheet presence/absence flag in the RAM 103 is set to ON, and information about the manual feed tray sheet presence/absence flag is stored in the RAM 103.

Steps S801 to S806 described above correspond to a process for setting various flags and the like when the sheet S is stacked on the manual feed tray 236. In this state, an air blowing operation process (FIG. 9), an air blowing execution flag setting process (FIG. 10), a sheet information setting process (FIG. 12) when the manual mode is set as the sheet information mode, a printing operation overall process (FIG. 14), and the like to be described below are executed.

Next, the control unit 100 waits until the sheet presence/absence detection sensor 401 is turned OFF (NO in step S807), i.e., repeatedly performs an operation of checking the state of the sheet presence/absence detection sensor 401 until the sheet S is removed from the manual feed tray 236. Then, if the sheet presence/absence detection sensor 401 is turned OFF (no sheet state is detected) (YES in step S807), the processing proceeds to step S808. In step S808, the manual feed tray sheet presence/absence flag in the RAM 103 is changed to the OFF state, and information about the manual feed tray sheet presence/absence flag is stored in the RAM 103.

Next, in step S809, the sheet information mode is determined using the value for the sheet information mode held in the RAM 103. If the manual mode is set as the sheet information mode (YES in step S809), the processing proceeds to step S810. In step S810, the sheet information held in the RAM 103 is cleared. On the other hand, if the fixed mode is set as the sheet information mode (NO in step S809), the sheet information held in the RAM 103 is not cleared, and the processing proceeds to step S811. In step S811, the air blowing execution flag in the RAM 103 is set to OFF (initialized), and information about the air blowing execution flag is stored in the RAM 103. After that, this sheet presence/absence determination process is repeatedly performed.

[Air Blowing Operation Process]

Next, an air blowing operation process according to the present exemplary embodiment will be described with reference to FIG. 9. FIG. 9 is a flowchart illustrating the air blowing operation process according to the present exemplary embodiment. This air blowing operation process is a process in which the control unit 100 determines whether a sheet S is stacked on the manual feed tray 236 by the above-described sheet presence/absence determination process to control whether to execute the air blowing operation. This flow of the air blowing operation process is constantly executed by the control unit 100 during activation of the image forming apparatus 201.

Specifically, in step S301, the control unit 100 determines whether a sheet S is set on the manual feed tray 236 using the manual feed tray sheet presence/absence flag held in the RAM 103 in the sheet presence/absence determination process described above. If the manual feed tray sheet presence/absence flag is OFF (NO in step S301), the control unit 100 determines that no sheet S is set (supported) on the manual feed tray 236, and continuously monitors the presence or absence of a sheet S until the manual feed tray sheet presence/absence flag is turned ON.

If the manual feed tray sheet presence/absence flag is ON (YES in step S301), it is determined that a sheet S is set on the manual feed tray 236, and then the processing proceeds to step S302. In step S302, it is determined whether the manual mode is set as the sheet information mode held in the RAM 103.

(When Fixed Mode is Set as Sheet Information Mode)

A process to be performed when the fixed mode is set as the sheet information mode (NO in step S302) will be described with reference to FIGS. 10 and 11. FIG. 10 is a flowchart illustrating the air blowing execution flag setting process to be performed when the fixed mode is set as the sheet information mode according to the present exemplary embodiment. FIG. 11 is a table storing a relationship between a paper type and a need for air blowing according to the present exemplary embodiment.

If the fixed mode is set as the sheet information mode (NO in step S302), the fixed mode sheet information (sheet type, sheet size, etc.) described above is already set for the sheet S set on the manual feed tray 236. Accordingly, in step S320, the information about the air blowing execution flag is updated with the fixed mode sheet information stored in the EEPROM 104, without performing the sheet setting process.

Specifically, as illustrated in FIG. 10, after the processing proceeds to step S320, in step S901, the control unit 100 retrieves the fixed mode sheet information stored in the EEPROM 104 in step S320 and copies the information into the RAM 103. Next, in step S902, the control unit 100 determines whether the sheet type (paper type) set in the fixed mode sheet information indicates coated paper. Specifically, as illustrated in FIG. 11, information about the need for air blowing depending on the paper type is stored in the table storing the relationship between the paper type stored in the ROM 102 and air blowing. In the present exemplary embodiment, if the sheet type (paper type) indicates any of “coated paper 1” to “coated paper 3” as a first type in this table, “required” is set in the item indicating the need for air blowing.

If a second type (“thin paper 1” to “thin paper 2”, “plain paper 1” to “plain paper 2”, “thick paper 1” to “thick paper 4”) that is different from the first type is set as the sheet type in this table, “not required” is set in the item indicating the need for air blowing. Accordingly, if the sheet type (paper type) indicates coated paper (first type) (YES in step S902), the processing proceeds to step S903. In step S903, the air blowing execution flag is set to ON. If the sheet type (paper type) does not indicate coated paper (second type) (NO in step S902), the processing proceeds to step S904. In step S904, the air blowing execution flag is set to OFF. After the air blowing execution flag setting process is executed as described above, the value (flag) is stored in the RAM 103, and then the processing proceeds to step S304 illustrated in FIG. 9. The relationship between the paper type and the need for air blowing illustrated in FIG. 11 is merely an example, and the relationship according to the present exemplary embodiment is not limited to this example.

(When Manual Mode is Set as Sheet Information Mode)

Next, a process to be executed if the manual mode is set as the sheet information mode (YES in step S302) will be described with reference to FIG. 12 and FIGS. 13A to 13D. FIG. 12 is a flowchart illustrating the sheet information setting process to be executed when the manual mode is set as the sheet information mode according to the present exemplary embodiment. FIG. 13A is an explanatory diagram illustrating a home screen and the operation unit 700. FIG. 13B is an explanatory diagram illustrating a sheet feed cassette setting screen. FIG. 13C is an explanatory diagram illustrating a sheet size setting screen. FIG. 13D is an explanatory diagram illustrating a sheet type setting screen.

If the manual mode is set as the sheet information mode (YES in step S302), the processing proceeds to step S303. In step S303, the control unit 100 can execute a manual mode sheet setting process every time a sheet S is set as described above. The user operates the operation unit 700 to execute this manual mode sheet setting process.

For example, when the user presses a sheet selection button on the display unit 720 illustrated in FIG. 13A, in step S601, the control unit 100 causes the screen to transition to a sheet feed cassette selection screen illustrated in FIG. 13B, i.e., the processing proceeds to the sheet feed cassette setting process illustrated in FIG. 12. In other words, the user selects any one of sheet feed cassettes (sheet containing portions) for which a setting of sheet information is to be made. The control unit 100 waits until the sheet feed cassette setting process ends (NO in step S602). In this case, for example, when a manual feed tray button is selected and a next button is pressed, the sheet feed cassette setting process ends (YES in step S602).

When these buttons are pressed, the control unit 100 causes the screen to transition to the sheet size setting screen illustrated in FIG. 13C. In other words, in step S603, the sheet size setting process illustrated in FIG. 12 is performed to set a sheet size. The control unit 100 waits until the sheet size setting process ends (NO in step S604). In this case, for example, when “A3-size” is selected as a sheet size of the sheet S set on the manual feed tray 236 and the next button is pressed, the sheet size setting process ends (YES in step S602).

When these buttons are pressed, the control unit 100 causes the screen to transition to the sheet type setting screen illustrated in FIG. 13D. In other words, in step S605, the sheet type setting process illustrated in FIG. 12 is performed to set a sheet type. The control unit 100 waits until the sheet type setting process ends (NO in step S606). In this case, for example, when “coated paper 1” is selected as the sheet type (paper type) of the sheet S set on the manual feed tray 236, and the sheet type setting process ends (YES in step S606). When the OK button is pressed, the screen transitions to an initial screen illustrated in FIG. 13A, and a sheet information registration operation in the manual mode ends.

In step S607, the control unit 100 determines whether the sheet type (paper type) set in the sheet information described above indicates coated paper. Specifically, as described above, the control unit 10 refers to the table storing the relationship between the paper type and the need for blowing air illustrated in FIG. 11, and if the sheet type (paper type) indicates coated paper (first type) (YES in step S607), the processing proceeds to step S608. In step S608, the air blowing execution flag is set to ON. If the sheet type (paper type) does not indicate coated paper (second type) (NO in step S902), the processing proceeds to step S609. In step S609, the air blowing execution flag is set to OFF. After the air blowing execution flag setting process is executed, the value (flag) is stored in the RAM 103, and then the processing proceeds to step S304 illustrated in FIG. 9.

In the manual mode described above, the sheet information is stored in the RAM 103 after the sheet setting process is executed once. Accordingly, there is no need to set sheet information every time a job is started. For example, in the case of executing a job with “A3-size” plain paper fed from the manual feed tray 236 again after “A3-size” plain paper is set on the manual feed tray 236 and a job is executed once, it may be sufficient to press the start key 702 (YES in step S1501 illustrated in FIG. 14).

(Air Blowing Operation)

Next, in step S304, the control unit 100 determines whether the air blowing execution flag determined based on the fixed mode sheet information or the sheet information set in the manual mode is ON. In other words, the control unit 100 determines whether to execute the air blowing operation on the sheet S set on the manual feed tray 236. If the air blowing execution flag is OFF (NO in step S304), it is determined that there is no need to perform the air blowing operation on the sheet S set on the manual feed tray 236, and then the processing proceeds to step S310 without performing the air blowing operation.

On the other hand, if the air blowing execution flag is ON (YES in step S304), the processing proceeds to step S305. In step S305, an air blowing executing flag indicating that the air blowing operation is to be started is set to ON so that the air blowing operation can be performed on the sheet S set on the manual feed tray 236. Then, information about the air blowing executing flag is stored in the RAM 103.

The air blowing operation can be started immediately by the control unit 100. However, if the air blowing operation is started immediately, there is a possibility that the air blowing operation may be started while the user is setting the sheet S to be used for printing on the manual feed tray 236. Accordingly, in the present exemplary embodiment, the control unit 100 waits for a sheet set waiting time as a set period for the user to set the sheet S to be used for printing on the manual feed tray 236 (NO in step S306). For example, 10 seconds are set as the sheet set waiting time. After the lapse of the sheet set waiting time (YES in step S306), the processing proceeds to step S307. In step S307, the control unit 100 issues an air blowing operation instruction to the fan control unit 510 (see FIG. 2) to start the air blowing operation.

In this case, for example, 10 seconds are set as the sheet set waiting time. However, the sheet set waiting time is not limited to this example. Particularly, in the present exemplary embodiment, the sheet set waiting time can be changed by an operation via the operation unit 700 or the like. If a shorter period of time is set as the sheet set waiting time, the time for the printing operation to be described below can be reduced and FCOT can be shortened. If a longer period of time is set as the sheet set waiting time, there is plenty of time for the user to set a sheet S, so that the user can properly set the sheet S. This makes it possible to reduce skew or the like of the sheet S and to improve the printing accuracy (quality).

When the control unit 100 issues the air blowing operation instruction to the fan control unit 510 (see FIG. 2), the fan motors 511M and 512M (see FIG. 2) of the air blowing portions 511A and 512A are driven and the air blowing operation of blowing air to the side surfaces of a bundle of sheets S is started. This operation makes it possible to separate several to several tens of sheets S on the upper part of the bundle of sheets from the rest of the bundle and lift the separated sheets S, and the lift of the sheets S can be suppressed by the lift suppressing plates 511c and 512c (see FIG. 4), which leads to a reduction in the adhesion between the sheets S.

Further, since the fan motors 511M and 512M start rotating from a rotation stopped state, it takes time for the fan motors 511M and 512M to reach a desired number of rotations (rotational speed), and it also takes time to stabilize the lift of the sheets S. Accordingly, in step S308, the control unit 100 waits until a period of, for example, 10 seconds, has elapsed from the start of the air blowing operation. In other words, a predetermined period is set as an air blowing operation period. The air blowing operation is continuously performed until the predetermined period has elapsed (NO in step S308). After the lapse of the predetermined period (YES in step S308), the processing proceeds to step S309. In step S309, the air blowing operation is stopped. In other words, the operation of driving the fan motors 511M and 512M is turned off. Since the air blowing operation ends, then in step S310, the control unit 100 sets the air blowing executing flag to OFF and stores information about the air blowing executing flag in the RAM 103.

Thus, the lifted sheets S are likely to be restored to the bundled state before lifting while air is released from the space between the sheets S. However, it takes time for the sheets S to be completely restored to the bundled state. Accordingly, the adhesion between the sheets S remains reduced for a while, and thus even a bundle of sheets of a paper type with high adhesion can be separated and fed one by one without being fed in an overlapped manner.

After that, in step S311, the control unit 100 determines whether there is no sheet S on the manual feed tray 236 using the above-described manual feed tray sheet presence/absence flag. If the manual feed tray sheet presence/absence flag is ON (NO in step S311), it can be determined that the sheets S with reduced adhesion therebetween by the air blowing operation remain on the manual feed tray 236. Accordingly, the control unit 100 determines that there is no need to perform the air blowing operation again and continuously monitors the OFF state of the manual feed tray sheet presence/absence flag. If the manual feed tray sheet presence/absence flag is turned OFF (YES in step S311), it can be determined that there is no sheet S on the manual feed tray 236, and the processing returns to step S301 to monitor a sheet S to be set on the manual feed tray 236.

[Printing Operation]

Next, a printing operation to be performed after the above-described air blowing operation is executed (including a case where the air blowing operation is skipped) will be described with reference to FIG. 14. FIG. 14 is a flowchart illustrating a printing operation process according to the present exemplary embodiment.

When the printing operation process is started, the control unit 100 monitors whether a print start request is issued from the host apparatus 1500, or whether a print start request is issued by, for example, pressing the start key 702 on the operation unit 700 (NO in step S1501). This monitoring operation is constantly executed by the control unit 100 during activation of the image forming apparatus 201.

If the print start request is issued (YES in step S1501), the processing proceeds to step S1502. In step S1502, the control unit 100 determines an air blowing operation status for the bundle of sheets on the manual feed tray 236 using the air blowing executing flag information held in the RAM 103. In other words, the control unit 100 determines whether the air blowing operation is being executed.

If the air blowing executing flag is ON (NO in step S1502), an air blowing operation for the paper type is being currently executed (e.g., coated paper), and thus the control unit 100 waits until the air blowing executing flag is turned OFF. If the air blowing executing flag is OFF (YES in step S1502), it is determined that the air blowing operation on the bundle of sheets on the manual feed tray 236 is completed (or the air blowing operation is skipped), and the processing proceeds to step S1503. In step S1503, the printing operation is started.

When the printing operation is started, the control unit 100 performs a preparation operation for printing in each unit of the image forming apparatus 201. After that, in step S1504, a sheet feeding operation (feeding control) is started to feed, for example, 15 sheets as the number of sheets S to be printed by the image forming apparatus 201.

This feeding operation indicates an operation of feeding the sheet S by rotating the pickup roller 501 by driving the feed motor 520 in a state where the pickup roller 501 is in contact with the uppermost sheet S of the sheet bundle of sheets. After that, if the sheets S are fed in an overlapped manner, a series of operations is performed in which the sheets S are separated by the separation portion constituted by the feed roller 502 and the retard roller 503 and passage of the sheet S is detected by the feed sensor 505.

When the feeding operation is started, in step S1505, it is determined whether there is no abnormality, such as paper jamming, during the printing operation. If there is no abnormality such as paper jamming (YES in step S1505), the processing proceeds to step S1509. In step S1509, it is determined whether printing of the number of sheets S is completed. In this case, for example, 15 sheets S are set as the number of sheets S, and the printing operation and the feeding operation are repeated until printing of the number of sheets S is completed (NO in step S1509).

If feeding and printing of the number of sheets S are completed (YES in step S1509), the processing proceeds to step S1510. In step S1510, the feeding operation and the operation of each unit in the image forming apparatus 201 are stopped to terminate the printing operation.

For example, if an abnormality, such as paper jamming, is detected during the printing operation and the feeding operation (NO in step S1505), an emergency stop operation is performed in each unit of the image forming apparatus 201. Next, in step S1506, it is determined whether the operation stop process is completed by the emergency stop operation. If the operation stop process is not completed (NO in step S1506), the control unit 100 waits until the operation stop process is completed. If the operation stop process is completed (YES in step S1506), the processing proceeds to step S1507. In step S1507, the control unit 100 determines whether to cancel the print job.

If the print job is to be cancelled (YES in step S1507), the processing proceeds to step S1510. In step S1510, the printing operation is finished. On the other hand, if the print job is not to be cancelled (NO in step S1507), the control unit 100 waits until printing can be resumed (NO in step S1508). If printing can be resumed (YES in step S1508), the processing returns to step S1503 to resume the printing operation. After the printing operation is resumed, in step S1509, it is determined whether feeding and printing of the number of sheets S are completed. If feeding and printing of the number of sheets S are not completed (NO in step S1509), the processing returns to step S1503 to repeat the feeding operation and the printing operation for the number of sheets S. If feeding and printing of the number of sheets S are completed (YES in step S1509), the processing proceeds to step S1510. In step S1510, the feeding operation and the operation of each unit in the image forming apparatus 201 are stopped to terminate the printing operation.

Summary of Present Exemplary Embodiment

As described above, in the present exemplary embodiment, assume that the set sheet type (paper type) indicates the first type, such as coated paper, which uses the air blowing operation, in a state where the fixed mode is selected. In this case, the air blowing operation by the air blowing portions 511A and 512A is started when the sheet presence/absence detection sensor 401 detects that the sheet S is supported on the manual feed tray 236. On the other hand, in a state where the manual mode is selected, the sheet type setting process is executed when the sheet presence/absence detection sensor 401 detects that the sheet S is supported on the manual feed tray 236. Then, if the set sheet type indicates the first type, the air blowing operation by the air blowing portions 511A and 512A is started.

Specifically, in the fixed mode, the air blowing operation by the air blowing portions 511A and 512A is started when the sheet S is set on the manual feed tray 236, instead of starting the air blowing operation in response to the print start request (see step S1501 in FIG. 14). In the manual mode, the air blowing operation is started upon execution of the sheet type setting process. This eliminates the need for starting the air blowing operation upon start of the printing operation, while making it possible to separate sheets having smooth surface properties, such as coated paper, by blowing air to the sheets, thereby reducing skew of a sheet. Consequently, in the case of correcting the skew of a sheet by the registration roller pair 240, the skew correction amount can be decreased, which makes it possible to reduce a variation in position among sheets conveyed to the secondary transfer portion 201D and to improve the printing accuracy (quality). Furthermore, the air blowing operation can be started before the print start request is issued, which makes it possible to reduce the adverse effect on the FCOT as the time for discharging the first sheet to the outside of the apparatus after receiving a print start request.

According to the present exemplary embodiment, particularly, in a state where the fixed mode is selected, the air blowing operation is started after the lapse of the sheet set waiting time after the sheet presence/absence detection sensor 401 detects that a sheet S is supported on the manual feed tray 236. This prevents the air blowing operation from being started while the user is setting a sheet S on the manual feed tray 236. As described above, the configuration in which the sheet set waiting time can be changed makes it possible to shorten FCOT and reduce skew of a sheet S.

Particularly, in the state where the fixed mode is selected, there is no need to set a sheet type when the sheet S is set on the manual feed tray 236, and setting of the sheet set waiting time can prevent the air blowing operation from being started immediately. However, the present exemplary embodiment is not limited to this operation. For example, the user may quickly finish the sheet type setting process in the manual mode, or the setting for the sheet type set in the previous manual mode may be used. Thus, even in the state where the manual mode is selected, setting of the sheet set waiting time can also prevent the air blowing operation from being started while the user is setting a sheet S on the manual feed tray 236.

Other Possible Exemplary Embodiments

The present exemplary embodiment described above illustrates an example where after the air blowing operation ends (YES in step S1502 illustrate in FIG. 14), the printing operation (see step S1503) is started, that is, the air blowing operation and the printing operation are not performed simultaneously. However, the present exemplary embodiment is not limited to this example. Any other operations may be performed as long as the air blowing operation and the printing operation are not performed in a completely simultaneous manner. Specifically, the printing operation may be started immediately before the air blowing operation is finished.

The present exemplary embodiment described above illustrates an example where the air blowing operation is started after the lapse of the sheet set waiting time, regardless of which one of the fixed mode and the manual mode is set as the sheet information mode. However, the present exemplary embodiment is not limited to this example. The air blowing operation may be started after the lapse of the sheet set waiting time when only one of the fixed mode and the manual mode is set. Particularly, in the manual mode, it takes time for the user to set sheet information, while in the fixed mode, it takes no time to set sheet information and it may be desirable to retrieve fixed mode sheet information from the EEPROM 104. Accordingly, the air blowing operation may be started after the lapse of the sheet set waiting time only in a case where the fixed mode is set. Instead of setting the sheet set waiting time, the amount of air to be blown in the air blowing operation may be reduced only during a period in which, for example, the user sets the sheet S on the manual feed tray 236.

The present exemplary embodiment described above illustrates an example where the image forming apparatus 201 includes the control unit 100 and the manual feed portion 235. However, the configuration of the image forming apparatus 201 is not limited to this example. For example, the control unit may be included in a sheet feeding apparatus, such as a scanner, which includes a structure for allowing a support portion to support sheets manually fed and enabling the support portion to move such that the support portion can be opened or closed with respect to an apparatus main body. The image forming apparatus is not limited to the image forming apparatus 201 according to the present exemplary embodiment, and may indicate an image forming system including a sheet feed cassette.

The present disclosure can also be implemented by executing the following processing. That is, a program for implementing one or more functions according to the exemplary embodiments described above is supplied to a system or an apparatus via a network or a storage medium, and one or more processors in a computer of the system or the apparatus read out and execute the program. The present disclosure can also be implemented by a circuit (e.g., an application-specific integrated circuit (ASIC) or the like) for implementing one or more functions according to the exemplary embodiments.

While the present disclosure has been described with reference to exemplary embodiments, it is to be understood that the disclosure is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.

This application claims the benefit of priority from Japanese Patent Application No. 2023-113940, filed Jul. 11, 2023, which is hereby incorporated by reference herein in its entirety.

Claims

1. A sheet feeding apparatus configured to feed a sheet, the apparatus comprising:

a sheet support portion located at a side surface of the sheet feeding apparatus and configured to support a plurality of sheets;

a feeding portion configured to feed the plurality of sheets supported on the sheet support portion one by one;

a sheet support detection portion configured to detect that sheets are supported on the sheet support portion;

a separation portion configured to separate the plurality of sheets supported on the sheet support portion by blowing air to the plurality of sheets; and

a control portion configured to selectively execute a first mode and a second mode, the first mode being a mode in which a sheet type setting operation for the sheets supported on the sheet support portion is executed in advance, the second mode being a mode in which the sheet type setting operation is executable upon detection that the sheets are supported on the support portion by the sheet support detection portion,

wherein in a case where a first type is set as a sheet type of the sheets in a state where the first mode is selected, the control portion starts air blowing by the separation portion upon detection that the sheets are supported on the sheet support portion by the sheet support detection portion, and

wherein in a case where the sheet type setting operation is executed upon detection that the sheets are supported on the sheet support portion by the sheet support detection portion and the first type is set as the sheet type in a state where the second mode is selected, the control portion starts air blowing by the separation portion.

2. The sheet feeding apparatus according to claim 1, wherein in a case where the first type is set as the sheet type in the state where the first mode is selected, the control portion starts air blowing by the separation portion after a lapse of a set period after detection that the sheets are supported on the sheet support portion by the sheet support detection portion.

3. The sheet feeding apparatus according to claim 2, wherein the control portion is configured to change the set period.

4. The sheet feeding apparatus according to claim 1, wherein the control portion starts feeding of the sheets by the feeding portion after completion of air blowing by the separation portion.

5. The sheet feeding apparatus according to claim 1,

wherein in a case where a second type different from the first type is set as the sheet type in the state where the first mode is selected, the control portion starts feeding of the sheets by the feeding portion upon detection that the sheets are supported on the sheet support portion by the sheet support detection portion, and

wherein in a case where the sheet type setting operation is executed upon detection that the sheets are supported on the sheet support portion by the sheet support detection portion and the second type is set as the sheet type in the state where the second mode is selected, the control portion starts feeding of the sheets by the feeding portion.

6. The sheet feeding apparatus according to claim 1, further comprising a side edge regulating plate movable in a width direction orthogonal to a sheet feeding direction and configured to regulate a position in the width direction of the sheets supported on the support portion,

wherein the separation portion includes a fan and a duct configured to blow air to sides of the sheets by guiding air blown from the fan to pass through the side edge regulating plate.

7. A sheet feeding apparatus configured to feed a sheet, the apparatus comprising:

a sheet support portion located at a side surface of the sheet feeding apparatus and configured to support a plurality of sheets;

a feeding portion configured to feed the plurality of sheets supported on the sheet support portion one by one;

a sheet support detection portion configured to detect that sheets are supported on the sheet support portion;

a separation portion configured to separate the plurality of sheets supported on the sheet support portion by blowing air to the plurality of sheets; and

a control portion configured to perform a sheet type setting operation on the sheets supported on the sheet support portion,

wherein in a case where a first type is set as a sheet type of the sheet, the control portion starts air blowing by the separation portion after a lapse of a set period after detection that the sheets are supported on the sheet support portion by the sheet support detection portion.

8. An image forming apparatus comprising:

the sheet feeding apparatus according to claim 1; and

an image forming portion configured to form an image on a sheet fed by the sheet feeding apparatus.