SHEET EJECTION DEVICE, IMAGE FORMING APPARATUS, AND SHEET STACKING METHOD

Abstract

A sheet ejection device includes an output tray to be stacked with a plurality of sheets. The output tray includes a first mount that mounts the sheets and a second mount that abuts on the first mount. The second mount mounts the sheets. A mover moves the first mount.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This patent application is based on and claims priority pursuant to 35 U.S.C. § 119 (a) to Japanese Patent Application Nos. 2023-091164, filed on Jun. 1, 2023, and 2024-035670, filed on Mar. 8, 2024, in the Japan Patent Office, the entire disclosure of each of which is hereby incorporated by reference herein.

BACKGROUND

Technical Field

Embodiments of this disclosure relate to a sheet ejection device, an image forming apparatus, and a sheet stacking method, and more particularly, to a sheet ejection device for being ejected with sheets, an image forming apparatus incorporating the sheet ejection device, and a sheet stacking method for stacking sheets.

Related Art

Related-art image forming apparatuses, such as copiers, facsimile machines, printers, and multifunction peripherals (MFP) having two or more of copying, printing, scanning, facsimile, plotter, and other functions, typically form an image on a recording medium according to image data.

Such image forming apparatuses include a sheet ejection device including an output tray onto which sheets adhered with an adhesive material such as toner are ejected.

SUMMARY

This specification describes below an improved sheet ejection device. In one embodiment, the sheet ejection device includes an output tray to be stacked with a plurality of sheets. The output tray includes a first mount that mounts the sheets and a second mount that abuts on the first mount. The second mount mounts the sheets. A mover moves the first mount.

This specification further describes an improved image forming apparatus. In one embodiment, the image forming apparatus includes an image forming device that forms an image on a plurality of sheets and a sheet ejection device to be ejected with the sheets. The sheet ejection device includes an output tray to be stacked with the sheets. The output tray includes a first mount that mounts the sheets and a second mount that abuts on the first mount. The second mount mounts the sheets. A mover moves the first mount.

This specification further describes an improved sheet stacking method. In one embodiment, the sheet stacking method includes stacking a plurality of sheets on a first mount and a second mount and moving the first mount.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete appreciation of embodiments of the present disclosure and many of the attendant advantages and features thereof can be readily obtained and understood from the following detailed description with reference to the accompanying drawings, wherein:

FIG. 1 is a schematic cross-sectional view of an image forming apparatus according to an embodiment of the present disclosure;

FIG. 2 is a block diagram of hardware of the image forming apparatus depicted in FIG. 1;

FIG. 3A a schematic perspective view of the image forming apparatus depicted in FIG. 1, illustrating an output tray incorporated therein;

FIG. 3B is a side view of the image forming apparatus depicted in FIG. 3A;

FIG. 4 is a schematic side cross-sectional view of the image forming apparatus depicted in FIG. 3B, illustrating a pivot mechanism that pivots a moving portion of the output tray;

FIG. 5 is a flowchart illustrating sheet shifting processes performed by the image forming apparatus depicted in FIG. 2;

FIG. 6 is a schematic side view of the image forming apparatus depicted in FIG. 3B, illustrating a plurality of sheets stacked on a mount face of the output tray when the mount face is bent;

FIG. 7 is a schematic plan view of the output tray depicted in FIG. 3A, illustrating side fences mounted on both ends of the output tray, respectively, in a width direction thereof;

FIG. 8A is a schematic perspective view of an image forming apparatus according to another embodiment of the present disclosure that incorporates an output tray including a moving portion that pivots downward such that one end of a mount face of the output tray in a width direction thereof is situated below a center of the mount face in the width direction of the output tray;

FIG. 8B is a schematic side view of the image forming apparatus depicted in FIG. 8A;

FIG. 9A is a schematic perspective view of an image forming apparatus according to yet another embodiment of the present disclosure that incorporates an output tray including moving portions that pivot downward such that both ends of a mount face of the output tray in a width direction thereof are situated below a center of the mount face in the width direction of the output tray;

FIG. 9B is a schematic side view of the image forming apparatus depicted in FIG. 9A;

FIG. 10A is a schematic perspective view of an image forming apparatus according to yet another embodiment of the present disclosure that incorporates an output tray including moving portions that pivot upward such that both ends of a mount face of the output tray in a width direction thereof are situated above a center of the mount face in the width direction of the output tray;

FIG. 10B is a schematic side view of the image forming apparatus depicted in FIG. 10A;

FIG. 11A is a schematic side view of an image forming apparatus according to yet another embodiment of the present disclosure that incorporates an output tray as a first modification example of the output tray depicted in FIG. 3B;

FIG. 11B is a schematic side view of an image forming apparatus according to yet another embodiment of the present disclosure that incorporates an output tray as a second modification example of the output tray depicted in FIG. 3B;

FIG. 11C is a schematic side view of an image forming apparatus according to yet another embodiment of the present disclosure that incorporates an output tray as a third modification example of the output tray depicted in FIG. 3B; and

FIG. 11D is a schematic side view of an image forming apparatus according to yet another embodiment of the present disclosure that incorporates an output tray as a fourth modification example of the output tray depicted in FIG. 3B.

The accompanying drawings are intended to depict embodiments of the present disclosure and should not be interpreted to limit the scope thereof. The accompanying drawings are not to be considered as drawn to scale unless explicitly noted. Also, identical or similar reference numerals designate identical or similar components throughout the several views.

DETAILED DESCRIPTION

In describing embodiments illustrated in the drawings, specific terminology is employed for the sake of clarity. However, the disclosure of this specification is not intended to be limited to the specific terminology so selected and it is to be understood that each specific element includes all technical equivalents that have a similar function, operate in a similar manner, and achieve a similar result.

Referring now to the drawings, embodiments of the present disclosure are described below. As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise.

Referring to the drawings, the following describes embodiments of the present disclosure. One skilled in the art readily changes and modifies the embodiments of the present disclosure into other embodiments within the scope of the technology of the present disclosure. The scope of the technology of the present disclosure encompasses such change and modification. The following describes the embodiments of the technology of the present disclosure, that do not limit the scope of the technology of the present disclosure.

FIG. 1 is a schematic cross-sectional view of an image forming apparatus 1 according to an embodiment of the present disclosure, illustrating a construction thereof.

In the embodiments described below, X-direction defines a front-back direction of the image forming apparatus 1 or a width direction of a sheet P. Y-direction defines a horizontal direction (e.g., a left-right direction) in FIG. 1 of the image forming apparatus 1 or a sheet ejection direction of the sheet P. Z-direction defines a vertical direction in FIG. 1.

As illustrated in FIG. 1, the image forming apparatus 1 is a copier that employs an electrophotographic method and includes devices below. For example, the image forming apparatus 1 includes an image forming device 5 serving as an image forming portion. The image forming device 5 includes a photoconductor 11, a charger 32, a developing device 12, a transfer device 31, and a cleaner 33. The image forming apparatus 1 further includes a reverse-ejection device 6, a reader 7, a writer 8, a sheet feeder 9, a fixing device 10, an output roller pair 15, and a sheet ejection device 4. The reverse-ejection device 6 includes a conveyance roller pair 19, a reverse roller pair 29, a reconveyance roller pair 20, and a conveyance roller pair 21. The sheet ejection device 4 includes an output tray 14 and a pivot mechanism 40 serving as a mover.

The reader 7 reads an image on an original placed on an original mount of the reader 7. The read image is converted into image data. The image forming device 5 forms a toner image according to the image data. In the image forming device 5, the charger 32 uniformly charges a surface of the photoconductor 11. Thereafter, the writer 8 emits exposure light L onto the photoconductor 11 according to the image data, forming an electrostatic latent image on the photoconductor 11. The developing device 12 visualizes the electrostatic latent image into a toner image. The transfer device 31 electrostatically transfers toner of the toner image onto a sheet P sent from the sheet feeder 9. The fixing device 10 fixes the toner of the toner image transferred on the sheet P thereon.

The image forming apparatus 1 further includes a feed roller 9a, a conveyance roller pair 13a, and a registration roller pair 13b. The conveyance roller pair 13a conveys the sheet P supplied from the sheet feeder 9 by the feed roller 9a to the image forming device 5 in a sheet conveyance direction 13. The registration roller pair 13b conveys the sheet P to the photoconductor 11 at a proper time when the transfer device 31 transfers the toner image formed on the photoconductor 11 onto the sheet P. The sheet P bearing the toner image is conveyed to the fixing device 10. The fixing device 10 softens and melts toner of the toner image on the sheet P under heat and pressure, thus fixing the toner image on the sheet P. The sheet P bearing the toner image fixed by the fixing device 10 is conveyed to the output tray 14 or the reverse-ejection device 6.

The reverse-ejection device 6 selectively conveys the sheet P to the output tray 14 or the photoconductor 11. For example, the reverse-ejection device 6 reverses the sheet P and ejects the sheet P onto the output tray 14. Alternatively, the reverse-ejection device 6 reverses the sheet P, and conveys and circulates the sheet P to the photoconductor 11 serving as an image bearer of the image forming device 5 again. After the sheet P passes through the fixing device 10, in a case that the sheet P is ejected onto an outside of the image forming apparatus 1 directly and regularly, the sheet P passes through the output roller pair 15 and is ejected onto the output tray 14.

In a case that the sheet P is conveyed to the reverse-ejection device 6, the sheet P is conveyed through a path in a sheet conveyance direction 16. In this case, the sheet P conveyed through the path in the sheet conveyance direction 16 is conveyed to the reverse roller pair 29 through the conveyance roller pair 19. The reverse roller pair 29 rotates forward and backward. The reverse roller pair 29 reverses and switches back the sheet P that bears the toner image on a front side of the sheet P and is conveyed through the path in the sheet conveyance direction 16. In order to eject the sheet P switched back by the reverse roller pair 29 onto the outside of the image forming apparatus 1, the reconveyance roller pair 20 conveys the sheet P through a path in a sheet conveyance direction 17 to the output roller pair 15 that ejects the sheet P onto the output tray 14.

In a case that the reverse-ejection device 6 reverses the sheet P, and conveys and circulates the sheet P to the image forming device 5 that forms a toner image on a back side of the sheet P, the reconveyance roller pair 20 and the conveyance roller pair 21 convey the sheet P switched back by the reverse roller pair 29 through a path in a sheet conveyance direction 18. The sheet P passes through a reverse conveyance path that is curved and interposed between the reconveyance roller pair 20 and the conveyance roller pair 21. Thus, the sheet P is guided to the conveyance roller pair 21. The reverse-ejection device 6 further includes conveyance roller pairs 22a, 22b, 22c, and 22d that convey the sheet P that has passed through the conveyance roller pair 21 and is reversed. The sheet P is conveyed and circulated to the photoconductor 11 serving as the image bearer of the image forming device 5 again. The output roller pair 15 ejects the sheet P onto the output tray 14.

The sheet P heated by the fixing device 10 is ejected onto the output tray 14 in a state in which the sheet P has an increased temperature (e.g., a high temperature). Hence, the toner of the toner image formed on the sheet P ejected on the output tray 14 is not cooled and solidified and therefore is soft. When a subsequent sheet P is ejected on the soft toner on the previous sheet P, the soft toner may adhere the subsequent sheet P to the previous sheet P bearing the soft toner, which is called blocking. In order to suppress blocking, the image forming apparatus 1 may include a fan that generates wind that blows against the previous sheet P placed on the output tray 14 or a cooling fan that is interposed between the fixing device 10 and the output roller pair 15. The cooling fan generates wind that blows against the sheet P conveyed straight from the fixing device 10 onto the outside of the image forming apparatus 1 through the output roller pair 15, thus cooling the sheet P. Accordingly, the sheet P is ejected onto the output tray 14 in a state in which the toner of the toner image on the sheet P is cooled and solidified, thus suppressing blocking.

However, if the image forming apparatus 1 conveys the sheet P at an increased speed to improve productivity, the sheet P passes through a sheet cooling region where the cooling fan cools the sheet P in a shortened time period. Hence, while the sheet P is conveyed through the sheet cooling region, the cooling fan may not cool the sheet P sufficiently. Accordingly, the sheet P may not be ejected onto the output tray 14 in a state in which the toner of the toner image on the sheet P is cooled and solidified, causing blocking. In order to cool the sheet P properly even if the sheet P passes through the sheet cooling region in the shortened time period, the cooling fan rotates with an increased number of rotations to increase an amount of wind that blows against the sheet P so as to improve efficiency in cooling the sheet P. However, as the number of rotations of the cooling fan increases, the cooling fan may increase power consumption excessively, resulting in loud wind noise from the cooling fan and loud noise from the image forming apparatus 1. Additionally, as the amount of wind that blows against the sheet P increases, the sheet P may flutter in the wind from the cooling fan and may be jammed.

Even in a case that the cooling fan generates wind that blows against the sheet P ejected on the output tray 14 to cool the sheet P, if the image forming apparatus 1 conveys the sheet P at the increased speed to improve productivity, the previous sheet P and the subsequent sheet P are conveyed to the output tray 14 with a shortened interval therebetween. Accordingly, the cooling fan may not cool and solidify the toner of the toner image on the previous sheet P before the subsequent sheet P is ejected onto the output tray 14, thus failing to suppress blocking. To address the circumstance, the cooling fan increases the number of rotations to increase the amount of wind that blows against the sheet P so as to improve efficiency in cooling the sheet P. Accordingly, the cooling fan may increase power consumption excessively, resulting in loud wind noise from the cooling fan and loud noise from the image forming apparatus 1. Additionally, as the amount of wind that blows against the sheet P increases, the sheet P may flutter on the output tray 14 in the wind from the cooling fan and may drop off the output tray 14.

In a process in which the soft toner of the toner image on the sheet P is cooled and solidified, if the sheets P that are ejected and stacked on the output tray 14 do not move, blocking occurs. Even if blocking occurs, in a case that the toner of the toner image on the previous sheet P, that is adhered to the subsequent sheet P ejected on the previous sheet P, is peeled off the subsequent sheet P, the toner of the toner image on the previous sheet P does not adhere to the subsequent sheet P again. Hence, according to an embodiment of the present disclosure, the output tray 14 includes a mount face that mounts the sheet P ejected onto the output tray 14. The pivot mechanism 40 serving as the mover pivots a part of the mount face to bend the mount face. The bent mount face deforms the sheets P stacked on the output tray 14 and moves the sheets P. Accordingly, even if the subsequent sheet P is stacked on the previous sheet P bearing the soft toner, the previous sheet P and the subsequent sheet P are immune from blocking. Even if blocking occurs, as the previous sheet P and the subsequent sheet P move, the subsequent sheet P adhered to the toner of the toner image formed on the previous sheet P peels off the previous sheet P.

Referring to the drawings, the following describes advantageous constructions of the image forming apparatus 1 according to the embodiments of the present disclosure.

FIG. 2 is a block diagram of hardware of the image forming apparatus 1 depicted in FIG. 1 as one example.

The image forming apparatus 1 further includes a controller 90. The controller 90 includes a central processing unit (CPU) 90a, a read-only memory (ROM) 90b, a random-access memory (RAM) 90c, a printer controller 90d, an image reader controller 90e, a storage controller 90f, an input controller 90g, and an output controller 90h, that are connected through a bus 90i.

The printer controller 90d of the controller 90 serves as an interface through which the CPU 90a controls hardware relating to a printer such as the image forming device 5, the sheet feeder 9, the writer 8, the reverse-ejection device 6, the fixing device 10, and the pivot mechanism 40. The image reader controller 90e serves as an interface through which the CPU 90a controls the reader 7.

The image forming apparatus 1 further includes a storage 93, an input device 94, and an output device 95. The storage controller 90f serves as an interface through which the CPU 90a controls the storage 93. The input controller 90g serves as an interface through which the CPU 90a controls the input device 94. The output controller 90h serves as an interface through which the CPU 90a controls the output device 95.

The controller 90 including the CPU 90a controls an entirety of the image forming apparatus 1. The CPU 90a starts an operating system (OS) with a boot program stored in the ROM 90b. The CPU 90a executes a control program stored in the storage 93 and the ROM 90b on the OS.

The RAM 90c is used as a temporary storage such as a main memory and a work area of the CPU 90a. The storage 93 is a nonvolatile storage that is readable and writable such as a hard disk drive (HDD). The storage 93 stores various data such as a control program that controls the entirety of the image forming apparatus 1, application programs, data that manage consumables, video indicating a series of operations that eliminates a maintenance event. The CPU 90a accesses the storage 93 through the storage controller 90f.

The CPU 90a reads the control program and the application programs from the storage 93 and the ROM 90b and executes the programs deployed in the RAM 90c, thus controlling the image forming apparatus 1.

In the image forming apparatus 1 according to the embodiment, the single CPU 90a executes processes illustrated in a flowchart described below by using the programs deployed in the single RAM 90c. Alternatively, the image forming apparatus 1 may employ other methods. For example, the CPU 90a may execute the processes illustrated in the flowchart described below by collaborating with a plurality of processors, the RAM 90c, the ROM 90b, and the storage 93. Alternatively, the CPU 90a may execute a part of the processes by using a hardware circuit such as an application-specific integrated circuit (ASIC) and a field programmable gate array (FPGA).

The CPU 90a controls the reader 7 through the image reader controller 90e to read an image on an original into image data. The CPU 90a collaborates with hardware coupled with the printer controller 90d to form a toner image on a sheet P. The image forming apparatus 1 further includes an upper limit detecting sensor 35 and a home position sensor 44. The CPU 90a collaborates with the printer controller 90d to control the pivot mechanism 40, the upper limit detecting sensor 35, and the home position sensor 44 to perform sheet shifting processes that shift the sheets P ejected on the output tray 14 as described below.

The input controller 90g connects the input device 94 to the controller 90 and receives an instruction of a user from the input device 94 including a touch panel and hardware keys. The output controller 90h connects the output device 95 to the controller 90 and controls the output device 95 including a display such as a liquid crystal display (LCD) and a cathode ray tube (CRT) display, thus displaying a control screen and video to the user. According to the embodiments of the present disclosure, the output device 95 serves as a display that displays and outputs information. Alternatively, the output device 95 may include a speaker that outputs voice in addition to the display. The input device 94 may include a microphone that inputs voice in addition to the touch panel and the hardware keys.

FIG. 3A is a schematic perspective view of the image forming apparatus 1, illustrating the output tray 14 according to the embodiment of the present disclosure. FIG. 3B is a schematic side view of the image forming apparatus 1.

As illustrated in FIGS. 3A and 3B, the output tray 14 is mounted on a side of the image forming apparatus 1 according to the embodiment. The output tray 14 includes a moving portion 14a and a secured portion 14b. The output tray 14 has a center C in the width direction (e.g., X-direction) of the sheet P, that is perpendicular to the sheet ejection direction (e.g., Y-direction) in which the sheet P is ejected onto the output tray 14. The center C defines a reference that divides the output tray 14 into a front portion and a rear portion thereof. The rear portion is a left part of the output tray 14 in FIGS. 3A and 3B, that is disposed farther from a front of the image forming apparatus 1 than the front portion is. The rear portion is the secured portion 14b. The front portion is a right part of the output tray 14 in FIGS. 3A and 3B, that is disposed closer to the front of the image forming apparatus 1 than the rear portion is. The front portion is the moving portion 14a. Since the moving portion 14a is disposed in proximity to the front of the image forming apparatus 1, the user who stands in front of the image forming apparatus 1 recognizes motion of the moving portion 14a readily.

The secured portion 14b is stationarily secured to an apparatus body of the image forming apparatus 1. The moving portion 14a pivots about the center C, as a fulcrum, of the output tray 14 in the width direction of the sheet P in a predetermined angular range. The output tray 14 further includes a mount face 140 that mounts the sheet P. The mount face 140 switches between a default position illustrated with a broken line and a deformation position illustrated with a solid line in FIGS. 3A and 3B. At the default position, a part of the mount face 140, that is defined by the secured portion 14b, and another part of the mount face 140, that is defined by the moving portion 14a, extend straight (e.g., horizontally) in the width direction of the sheet P and define an identical, straight face. At the deformation position, the mount face 140 is bent at the center C of the output tray 14 in the width direction of the sheet P such that the moving portion 14a at the deformation position is inclined upward in an upward direction U with respect to the moving portion 14a at the default position. The image forming apparatus 1 further includes a sheet outlet 30 through which the sheet P is ejected onto the output tray 14. The mount face 140 of the output tray 14 is longer than a length of a slit of the sheet outlet 30 in the width direction of the sheet P, that is perpendicular to the sheet ejection direction.

According to the embodiment, the moving portion 14a at the default position defines the mount face 140 that is parallel to a horizontal direction in FIGS. 3A and 3B. Alternatively, the mount face 140 may include an upstream portion and a downstream portion in the sheet ejection direction. The mount face 140 may be inclined in the sheet ejection direction such that the downstream portion is disposed above or below the upstream portion as long as the sheet P does not drop off the mount face 140. The home position sensor 44 detects the moving portion 14a situated at the default position.

FIG. 4 is a schematic cross-sectional view of the image forming apparatus 1, illustrating the pivot mechanism 40 that pivots the moving portion 14a as one example.

The image forming apparatus 1 further includes a pivot 34 that is mounted on the secured portion 14b of the output tray 14 or the apparatus body of the image forming apparatus 1. The pivot 34 extends in the sheet ejection direction and pivotally supports the moving portion 14a of the output tray 14. The pivot mechanism 40 includes a motor 43, a rack gear 42, and a pinion gear 41. The motor 43 serves as a driver. The rack gear 42 is mounted on an end of the moving portion 14a in the width direction of the sheet P. The rack gear 42 is an arc curved about a center of the pivot 34. The pinion gear 41 meshes with the rack gear 42. The pinion gear 41 is mounted on a driving shaft 43a of the motor 43. Alternatively, the pivot mechanism 40 may further include a plurality of gears through which a driving force generated by the motor 43 is transmitted to the pinion gear 41.

FIG. 5 is a flowchart of the sheet shifting processes for pivoting the moving portion 14a.

When the image forming apparatus 1 starts a print job, the moving portion 14a is situated at the default position illustrated with a solid line in FIG. 4. In step S1, the controller 90 depicted in FIG. 2 determines whether or not the image forming apparatus 1 finishes the print job. If the controller 90 determines that the image forming apparatus 1 does not finish the print job (NO in step S1), the controller 90 determines whether or not the upper limit detecting sensor 35 disposed below the sheet outlet 30 and above the output tray 14 in FIG. 4 detects that an amount of the sheets P stacked on the output tray 14 reaches an upper limit amount in step S2. If the controller 90 determines that the image forming apparatus 1 finishes the print job (YES in step S1) or that the upper limit detecting sensor 35 detects that the amount of the sheets P stacked on the output tray 14 reaches the upper limit amount (YES in step S2), the controller 90 controls the pivot mechanism 40 to start pivoting the moving portion 14a to start the sheet shifting processes in step S3. As the pivot mechanism 40 starts the sheet shifting processes, the pivot mechanism 40 drives the motor 43 to rotate the pinion gear 41. According to a rotation direction of the pinion gear 41, the rack gear 42 moves to pivot the moving portion 14a about the pivot 34 counterclockwise in FIG. 4 in step S3. Thus, the moving portion 14a pivots upward. In step S4, the controller 90 determines whether or not the moving portion 14a reaches the deformation position illustrated with a broken line in FIG. 4. If the controller 90 determines that the moving portion 14a reaches the deformation position (YES in step S4), the controller 90 controls the pivot mechanism 40 to stop driving the motor 43 in step S5, thus interrupting pivoting of the moving portion 14a.

If the motor 43 is a stepping motor, the controller 90 determines whether or not the moving portion 14a reaches the deformation position based on a number of steps. If the motor 43 is a direct current (DC) motor, the controller 90 determines whether or not the moving portion 14a reaches the deformation position based on a driving time period for which the motor 43 is driven. Alternatively, the image forming apparatus 1 may further include a detecting sensor that detects the moving portion 14a. The controller 90 determines whether or not the moving portion 14a reaches the deformation position based on a detection result sent from the detecting sensor.

The deformation position of the moving portion 14a is defined by a pivot angle of the moving portion 14a, that is formed from the default position, and a bend angle of the mount face 140. While the moving portion 14a is at the deformation position, even if the output tray 14 mounts the sheets P in the upper limit amount, the sheets P stacked on the output tray 14 do not block the sheet outlet 30.

As illustrated in FIG. 6, as the moving portion 14a moves from the default position to the deformation position, the mount face 140 of the output tray 14 is bent at the center C, as the reference, of the mount face 140 in the width direction of the sheets P. Accordingly, one end (e.g., a right end in FIG. 6) of the mount face 140 in the width direction of the sheets P, that is disposed in proximity to the front of the image forming apparatus 1, is disposed above the center C of the mount face 140 in the width direction of the sheets P. As the mount face 140 is bent, the plurality of sheets P stacked on the mount face 140 is deformed in accordance with bending of the mount face 140. Accordingly, the mount face 140 shifts the stacked sheets P from each other in the width direction thereof at one end (e.g., a right end in FIG. 6) of each of the sheets P in the width direction thereof, that is disposed on the moving portion 14a. The stacked sheets P shift by weight leftward in FIG. 6 toward a rear of the image forming apparatus 1, that is opposite to the front of the image forming apparatus 1, at another end (e.g., a left end in FIG. 6) of each of the sheets P in the width direction thereof, that is disposed on the secured portion 14b, with a shift amount smaller than a shift amount at the one end of each of the sheets P in the width direction thereof. Hence, at the one end of each of the stacked sheets P in the width direction thereof, the one end of an upper sheet P of the stacked sheets P shifts rightward in FIG. 6 toward the front of the image forming apparatus 1 in a shift amount greater than a shift amount of the one end of a lower sheet P of the stacked sheets P. Thus, the stacked sheets P are immune from blocking. Additionally, as the stacked sheets P shift from each other in the width direction thereof, the sheets P adhered to each other by soft toner peel off each other, eliminating blocking. As described above, according to the embodiment, even if a sheet P is stacked on soft toner on another sheet P, the output tray 14 suppresses blocking. Additionally, the image forming apparatus 1 may include a cooling fan that is oriented to a conveyance path that is disposed downstream from the fixing device 10 in the sheet ejection direction inside the apparatus body of the image forming apparatus 1. Alternatively, the cooling fan may be oriented to the output tray 14. The cooling fan cools the sheets P, suppressing blocking.

As illustrated in FIG. 5, in step S6, the controller 90 determines whether or not a predetermined time period elapses after the pivot mechanism 40 bends the mount face 140. If the controller 90 determines that the predetermined time period elapses after the pivot mechanism 40 bends the mount face 140 (YES in step S6), the controller 90 controls the pivot mechanism 40 to start pivoting the moving portion 14a backward in step S7. For example, the controller 90 controls the pivot mechanism 40 to rotate the motor 43 backward to return the moving portion 14a situated at the deformation position to the default position in step S7. Accordingly, the stacked sheets P move in a direction in which shifting of the stacked sheets P at the one end (e.g., the right end in FIG. 6) of each of the sheets P, that is in proximity to the front of the image forming apparatus 1 and disposed above the moving portion 14a, is cancelled. In step S8, the controller 90 determines whether or not the home position sensor 44 detects the moving portion 14a reaching the default position. If the controller 90 determines that the home position sensor 44 detects the moving portion 14a reaching the default position (YES in step S8), the controller 90 controls the pivot mechanism 40 to stop driving the motor 43 in step S9 so as to interrupt backward pivoting of the moving portion 14a, thus finishing the sheet shifting processes.

As described above, at a job finish time when the image forming apparatus 1 finishes the print job or an upper limit detection time when the upper limit detecting sensor 35 detects that the amount of the sheets P stacked on the output tray 14 reaches the upper limit amount, the pivot mechanism 40 starts the sheet shifting processes. However, the pivot mechanism 40 performs the sheet shifting processes before the soft toner on the sheets P stacked on the output tray 14 is cooled completely. When the soft toner on the sheets P is cooled completely, the cooled toner adheres the sheets P to each other strongly. Accordingly, even if the pivot mechanism 40 performs the sheet shifting processes as described above, the sheets P adhered to each other by the cooled toner may not peel off each other. Consequently, the pivot mechanism 40 may not eliminate blocking.

To address the circumstance, in a case that toner on a first sheet P ejected onto the output tray 14 first is cooled and solidified completely at the job finish time when the image forming apparatus 1 finishes the print job or the upper limit detection time when the upper limit detecting sensor 35 detects that the amount of the sheets P stacked on the output tray 14 reaches the upper limit amount, the pivot mechanism 40 performs the sheet shifting processes at a time earlier than the job finish time and the upper limit detection time. For example, at a time when a predetermined time period, for which a plurality of sheets P is ejected onto the output tray 14, elapses after the first sheet P is ejected onto the output tray 14, even if the image forming apparatus 1 does not finish the print job or even if the upper limit detecting sensor 35 does not detect that the amount of the sheets P stacked on the output tray 14 reaches the upper limit amount, the pivot mechanism 40 performs the sheet shifting processes. Accordingly, before soft toner on the sheets P is cooled completely, the pivot mechanism 40 causes the mount face 140 to deform the sheets P, shifting the sheets P from each other. Thus, the sheets P adhered to each other by the toner peel off each other properly, eliminating blocking.

If the moving portion 14a is situated at the deformation position, the sheets P may not be ejected onto the mount face 140 properly. Hence, before the pivot mechanism 40 performs the sheet shifting processes, conveyance of the sheets P is interrupted. After the pivot mechanism 40 finishes the sheet shifting processes, conveyance of the sheets P is resumed preferably.

The image forming apparatus 1 may convey the sheets P with an increased interval that decreases productivity. For example, the image forming apparatus 1 may perform duplex printing or the like that achieves a productivity lower than a productivity of single-sided printing. The image forming apparatus 1 may convey the sheets P at a conveyance speed in a low-speed print mode or the like used to print on thick paper or the like, that is lower than a conveyance speed in a high-speed print mode, thus decreasing productivity. In such cases, whenever a sheet P is stacked onto the output tray 14, that is, before a subsequent sheet P is stacked on a previous sheet P on the output tray 14, the output tray 14 may perform the sheet shifting processes, thus suppressing blocking properly.

As described above, the rack gear 42 and the pinion gear 41 pivot the moving portion 14a. Alternatively, for example, an actuator may lift and lower one end of the moving portion 14a, that is disposed in proximity to the front of the image forming apparatus 1 and is opposite to another end disposed in proximity to the pivot 34, thus pivoting the moving portion 14a. Yet alternatively, the pivot 34 coupled with the moving portion 14a may be coupled with a gear and a motor disposed inside the image forming apparatus 1, thus pivoting the moving portion 14a.

The output tray 14 according to the embodiment includes an end fence attached to a downstream end of the output tray 14 in the sheet ejection direction. However, if a length of the output tray 14 is shorter than a length of a maximum size sheet P that is available in the image forming apparatus 1 in the sheet ejection direction, the maximum size sheet P may protrude beyond the downstream end of the output tray 14 in the sheet ejection direction. To address the circumstance, the end fence is removed or retracted from the output tray 14. A length of the output tray 14 in the width direction of the sheet P is longer than a width of the maximum size sheet P in the width direction thereof. Hence, as illustrated in FIG. 7, the output tray 14 includes side fences 141 that are disposed at both ends of the output tray 14, respectively, in the width direction of the sheet P.

When the moving portion 14a pivots upward to the deformation position while the moving portion 14a is stacked with sheets P having a smooth, slippery surface, for example, even if left ends in FIG. 6 of the sheets P, that are stacked on the secured portion 14b, slide in the width direction of the sheets P, the left, side fence 141 stops the sheets P. Thus, the side fence 141 prevents the sheets P from dropping off from one end (e.g., a left end in FIG. 7) of the output tray 14 in the width direction of the sheets P.

As described below with reference to FIGS. 8A and 8B, an image forming apparatus 1A includes an output tray 14A including a moving portion 14aA, the secured portion 14b, and a mount face 140A. When the moving portion 14aA pivots downward in a downward direction D to the deformation position, a lower sheet P of a plurality of sheets P stacked on the output tray 14A shifts toward a front of the image forming apparatus 1A farther than an upper sheet P of the sheets P stacked on the output tray 14A, suppressing blocking. However, as the moving portion 14aA moves, right ends in FIG. 8B of the sheets P, that are disposed in proximity to the front of the image forming apparatus 1A and stacked on the moving portion 14aA, may slide and move by weight of the sheets P in the width direction of the sheets P. To address the circumstance, the right, side fence 141 stops the sheets P, preventing the sheets P from dropping off from the right end in FIG. 8B of the output tray 14A, that is disposed in proximity to the front of the image forming apparatus 1A.

As illustrated in FIGS. 8A and 8B, the pivot mechanism 40 pivots the moving portion 14aA such that one end of the mount face 140A in the width direction of the sheets P is situated lower than the center C of the mount face 140A in the width direction of the sheets P. With the output tray 14A also, as illustrated in FIGS. 8A and 8B, the mount face 140A of the output tray 14A is bent at the center C, as the reference, of the mount face 140A in the width direction of the sheets P. Accordingly, the sheets P stacked on the mount face 140A deform in accordance with bending of the mount face 140A. Consequently, a contact face of a sheet P, that contacts toner of a toner image on another sheet P, moves, preventing and eliminating blocking.

FIGS. 9A and 9B illustrate an image forming apparatus 1B that includes an output tray 14B including a mount face 140B, two moving portions 14al and 14a2, and two pivot mechanisms 40 that pivot the moving portions 14al an 14a2, respectively. The mount face 140B is bent such that both ends of the mount face 140B in the width direction of the sheets P are situated below the center C of the mount face 140B in the width direction of the sheets P.

FIGS. 10A and 10B illustrate an image forming apparatus 1C that includes an output tray 14C including two moving portions 14a1A and 14a2A and a mount face 140C. The mount face 140C is bent such that both ends of the mount face 140C in the width direction of the sheets P are situated above the center C of the mount face 140C in the width direction of the sheets P.

With the output tray 14 including the secured portion 14b depicted in FIG. 6 and the output tray 14A including the secured portion 14b depicted in FIG. 8B, the sheets P stacked on the secured portion 14b shift slightly in the width direction of the sheets P. However, the output trays 14 and 14A suppress blocking. As illustrated in FIG. 9A, the output tray 14B includes the moving portions 14al and 14a2. As illustrated in FIG. 10A, the output tray 14C includes the moving portions 14a1A and 14a2A. The pivot mechanisms 40 pivot the moving portions 14a1, 14a2, 14a1A, and 14a2A, respectively, about the center C, as the fulcrum, of the output trays 14B and 14C in the width direction of the sheets P. Accordingly, as illustrated in FIGS. 9B and 10B, an upper sheet P shifts substantially from toner of a toner image on a lower sheet P on which the upper sheet P is stacked at both ends (e.g., a left end and a right end in FIGS. 9B and 10B) of the upper sheet P in the width direction of the upper sheet P and the lower sheet P, thus suppressing blocking more properly.

As described above, the pivot mechanism 40 moves or pivots a moving portion (e.g., the moving portions 14a, 14aA, 14a1, 14a2, 14a1A, and 14a2A) such that at least one end of a mount face (e.g., the mount faces 140, 140A, 140B, and 140C) in the width direction of the sheets P moves upward or downward with respect to the center C of the mount face in the width direction of the sheets P. Alternatively, the at least one end of the mount face in the width direction of the sheets P may move upward and downward with respect to the center C of the mount face in the width direction of the sheets P so that the at least one end of the mount face in the width direction of the sheets P moves in an increased motion range. Accordingly, the upper sheet P moves with respect to the toner of the toner image formed on the lower sheet P twice, that is, at a first time when the at least one end of the mount face in the width direction of the upper sheet P and the lower sheet P moves upward and a second time when the at least one end of the mount face moves downward. Consequently, the upper sheet P adhered to the toner of the toner image formed the lower sheet P peels off the lower sheet P effectively, thus suppressing blocking more properly.

As described above, an output tray (e.g., the output trays 14, 14A, 14B, and 14C) is divided into two portions in the width direction of the sheets P. A mount face (e.g., the mount faces 140, 140A, 140B, and 140C) of the output tray is bent at the center C, as the reference, of the mount face in the width direction of the sheets P. Alternatively, the output tray may be divided differently.

For example, FIG. 11A illustrates an image forming apparatus 1D that includes an output tray 14D divided into three portions in the width direction of the sheets P. The output tray 14D includes a mount face 140D, a secured portion 14bA as a center portion, and moving portions 14aB as one end portion and another end portion, respectively, in the width direction of the sheets P. For example, the secured portion 14bA is interposed between the moving portions 14aB in the width direction of the sheets P. The mount face 140D is bent at two positions, that is, centers C1 and C2, as references, in the width direction of the sheets P, respectively.

FIG. 11B illustrate an image forming apparatus 1E that includes an output tray 14E including a moving portion 14aC, a secured portion 14bB, and a mount face 140E. The output tray 14E is divided into two portions in the sheet ejection direction (e.g., Y-direction). The mount face 140E is bent at the center C, as the reference, of the mount face 140E in the sheet ejection direction.

According to the embodiments described above, a mount face (e.g., the mount faces 140, 140A, 140B, 140C, 140D, and 140E) mounted on a moving portion (e.g., the moving portions 14a, 14aA, 14a1, 14a2, 14a1A, 14a2A, 14aB, and 14aC) and an entirety of a lower face of the moving portion pivot. Alternatively, the mount face mounted on the moving portion may pivot and the lower face of the moving portion may not pivot and therefore may be stationary.

For example, FIG. 11C illustrates an image forming apparatus 1F that includes an output tray 14F including a moving portion 14aD, the secured portion 14b, and a mount face 140F. The mount face 140F disposed on the moving portion 14aD pivots in the upward direction U. The lower face of the moving portion 14aD does not pivot and therefore is stationary.

As illustrated in FIG. 4, the moving portion 14a pivots about the pivot 34. Conversely, as illustrated in FIG. 11D, an image forming apparatus 1G includes an output tray 14G including a moving portion 14aE, the secured portion 14b, and mount faces 140a and 140b. The moving portion 14aE moves vertically in a state in which the moving portion 14aE extends horizontally. The pivot mechanism 40 moves the moving portion 14aE to a position where the mount face 140a mounted on the moving portion 14aE is stepped up with respect to the mount face 140b mounted on the secured portion 14b. With the output trays 14F and 14G also, the sheets P stacked on the mount faces 140F, 140a, and 140b shift from each other, thus being immune from blocking. Alternatively, the moving portion 14a may be bent and moved with respect to the secured portion 14b, warping the mount face 140.

The above describes the embodiments of the present disclosure. However, the technology of the present disclosure is not limited to the specific embodiments and allows various deformation and modification within the scope of the present disclosure unless the above descriptions limit deformation and modification.

The embodiments described above are examples and achieve advantages peculiar to aspects below, respectively.

A description is provided of a first aspect of the technology of the present disclosure.

As illustrated in FIGS. 1, 3A, 3B, and 4, a sheet ejection device (e.g., the sheet ejection device 4) includes an output tray (e.g., the output trays 14, 14A, 14B, 14C, 14D, 14E, 14F, and 14G) onto which a sheet (e.g., the sheet P) fixed with toner is ejected. The sheet ejection device further includes a mount face (e.g., the mount faces 140, 140A, 140B, 140C, 140D, 140E, 140F, 140a, and 140b) and a mover (e.g., the pivot mechanism 40). The mount face mounts a plurality of sheets (e.g., the sheets P) ejected onto the output tray. The mover moves a part of the mount face. For example, the output tray includes a first mount (e.g., the moving portions 14a, 14aA, 14a1, 14a2, 14a1A, 14a2A, 14aB, 14aC, 140F, and 14aE) that mounts the sheets and a second mount (e.g., the secured portions 14b, 14bA, and 14bB) that abuts on the first mount. The second mount mounts the sheets. The mover moves the first mount.

A description is provided of a comparative image forming apparatus.

The comparative image forming apparatus includes a fan that generates wind that blows against a previous sheet placed on an output tray, cooling the previous sheet. Before a subsequent sheet is ejected onto the output tray, the fan cools and solidifies toner of a toner image formed on the previous sheet, suppressing blocking. However, the comparative image forming apparatus conveys the previous sheet and the subsequent sheet at a high speed to improve productivity. Hence, the comparative image forming apparatus ejects the previous sheet and the subsequent sheet onto the output tray with a decreased interval therebetween. Accordingly, the fan may not cool and solidify the toner of the toner image on the previous sheet sufficiently before the subsequent sheet is ejected onto the output tray, generating blocking.

While the fan cools and solidifies the soft toner on the previous sheet, if the previous sheet and the subsequent sheet ejected and stacked on the previous sheet on the output tray do not move, blocking may occur. To address the circumstance, the sheet ejection device according to the first aspect includes the mover that moves a part of the mount face. When a plurality of sheets is stacked on the output tray, the mover moves a part of the mount face to deform the sheets stacked on the mount face so as to move the sheets stacked on the mount face and shift the sheets from each other. Accordingly, even if a subsequent sheet is ejected onto soft toner of a toner image on a previous sheet while the soft toner is not cooled and solidified, the mount face suppresses blocking. Thus, even if the sheet ejection device is ejected with the sheets at a high speed to improve productivity, the sheet ejection device suppresses blocking properly.

A description is provided of a second aspect of the technology of the present disclosure.

Based on the first aspect, as the plurality of sheets is ejected onto the mount face, the mover moves a part of the mount face. For example, as the plurality of sheets is ejected onto the output tray, the mover moves the first mount.

Accordingly, as described above in the embodiments, as a part of the mount face moves, the mount face deforms the plurality of sheets stacked on the mount face, shifting the sheets from each other. Consequently, the mount face suppresses blocking.

A description is provided of a third aspect of the technology of the present disclosure.

Based on the first aspect or the second aspect, the mover moves an end of the mount face in a width direction (e.g., X-direction) of the sheets in one of an upward direction (e.g., the upward direction U) and a downward direction (e.g., the downward direction D) with respect to a center (e.g., the center C) of the mount face in the width direction of the sheets. For example, the mover moves the first mount in at least one of the upward direction or the downward direction with respect to the center of the output tray in the width direction of the sheets.

Accordingly, as described above in the embodiments, the mount face is bent at the center, as a reference, of the mount face in the width direction of the sheets. Consequently, the plurality of sheets stacked on the mount face is deformed along the bent mount face. Thus, the mount face shifts the sheets from each other in the width direction of the sheets, suppressing blocking properly.

A description is provided of a fourth aspect of the technology of the present disclosure.

Based on the third aspect, the mover moves one end of the mount face in the width direction of the sheets in one of the upward direction and the downward direction with respect to the center of the mount face in the width direction of the sheets. The width direction is perpendicular to a sheet ejection direction (e.g., Y-direction) in which the sheets are ejected onto the output tray.

Accordingly, the mount face is bent at the center, as the reference, of the mount face in the width direction of the sheets. Consequently, the plurality of sheets stacked on the mount face is deformed along the bent mount face. Thus, the mount face shifts the sheets from each other in the width direction of the sheets, suppressing blocking properly.

A description is provided of a fifth aspect of the technology of the present disclosure.

Based on the third aspect, the mover moves both ends of the mount face in the width direction of the sheets in one of the upward direction and the downward direction with respect to the center of the mount face in the width direction of the sheets. For example, the mover moves the first mount and the second mount in at least one of the upward direction or the downward direction with respect to the center of the output tray in the width direction of the sheets.

Accordingly, as described above with reference to FIGS. 9A, 9B, 10A, and 10B, compared to a configuration in which one end of the mount face in the width direction of the sheets moves in one of the upward direction and the downward direction with respect to the center of the mount face in the width direction of the sheets, the mount face according to the fifth aspect substantially moves and shifts the sheets from each other in the width direction of the sheets, suppressing blocking properly.

A description is provided of a sixth aspect of the technology of the present disclosure.

As illustrated in FIG. 1, an image forming apparatus (e.g., the image forming apparatuses 1, 1A, 1B, 1C, 1D, 1E, 1F, and 1G) includes an image forming device (e.g., the image forming device 5) and a sheet ejection device (e.g., the sheet ejection device 4). The image forming device forms a toner image on a sheet (e.g., the sheet P). The sheet ejection device is ejected with the sheet bearing the toner image, that is ejected onto an outside of an apparatus body of the image forming apparatus. The sheet ejection device is configured based on any one of the first to fifth aspects.

Accordingly, the image forming apparatus suppresses noise therefrom and jamming of the sheets while suppressing blocking.

A description is provided of a seventh aspect of the technology of the present disclosure.

As illustrated in FIG. 5, a sheet stacking method for stacking a plurality of sheets fixed with toner includes stacking the plurality of sheets on a mount face (e.g., the mount faces 140, 140A, 140B, 140C, 140D, 140E, 140F, 140a, and 140b). The sheet stacking method further includes moving a part of the mount face. For example, the sheet stacking method includes stacking the plurality of sheets on the first mount and the second mount and moving the first mount.

Accordingly, the sheet stacking method suppresses noise from a sheet ejection device (e.g., the sheet ejection device 4) incorporating the mount face and jamming of the sheets while suppressing blocking.

According to the embodiments described above, the image forming apparatus 1 is a copier. Alternatively, the image forming apparatus 1 may be a printer, a facsimile machine, a multifunction peripheral (MFP) having at least two of copying, printing, scanning, facsimile, and plotter functions, an inkjet recording apparatus, or the like.

The above-described embodiments are illustrative and do not limit the present invention. Thus, numerous additional modifications and variations are possible in light of the above teachings. For example, elements and/or features of different illustrative embodiments may be combined with each other and/or substituted for each other within the scope of the present invention. Any one of the above-described operations may be performed in various other ways, for example, in an order different from the one described above.

The functionality of the elements disclosed herein may be implemented using circuitry or processing circuitry which includes general purpose processors, special purpose processors, integrated circuits, application specific integrated circuits (ASICs), digital signal processors (DSPs), field programmable gate arrays (FPGAs), conventional circuitry and/or combinations thereof which are configured or programmed to perform the disclosed functionality. Processors are considered processing circuitry or circuitry as they include transistors and other circuitry therein. In the disclosure, the circuitry, units, or means are hardware that carry out or are programmed to perform the recited functionality. The hardware may be any hardware disclosed herein or otherwise known which is programmed or configured to carry out the recited functionality. When the hardware is a processor which may be considered a type of circuitry, the circuitry, means, or units are a combination of hardware and software, the software being used to configure the hardware and/or processor.

Claims

1. A sheet ejection device comprising:

an output tray to be stacked with a plurality of sheets,

the output tray including: a first mount to mount the sheets; and a second mount abutting on the first mount, the second mount to mount the sheets; and

a mover to move the first mount.

2. The sheet ejection device according to claim 1,

wherein the first mount and the second mount define a mount face to mount the sheets.

3. The sheet ejection device according to claim 1,

wherein the plurality of sheets includes a sheet fixed with toner.

4. The sheet ejection device according to claim 1,

wherein, as the plurality of sheets is ejected onto the output tray, the mover moves the first mount.

5. The sheet ejection device according to claim 1,

wherein the first mount abuts on the second mount in a width direction of the sheets.

6. The sheet ejection device according to claim 5,

wherein the mover moves the first mount in at least one of an upward direction or a downward direction with respect to a center of the output tray in the width direction of the sheets.

7. The sheet ejection device according to claim 6,

wherein the mover moves the second mount in at least one of the upward direction or the downward direction with respect to the center of the output tray in the width direction of the sheets.

8. The sheet ejection device according to claim 5,

wherein the width direction of the sheets is perpendicular to a sheet ejection direction in which the sheets are ejected onto the output tray.

9. The sheet ejection device according to claim 8,

wherein the output tray further includes a third mount to mount the sheets,

wherein the second mount is interposed between the first mount and the third mount in the width direction of the sheets, and

wherein the mover moves the third mount.

10. The sheet ejection device according to claim 1,

wherein the first mount abuts on the second mount in a sheet ejection direction in which the sheets are ejected onto the output tray.

11. The sheet ejection device according to claim 1,

wherein the first mount includes a mount face to mount the sheets, the mount face moved by the mover.

12. The sheet ejection device according to claim 1,

wherein the mover lifts the first mount to a position where the first mount is stepped up with respect to the second mount.

13. The sheet ejection device according to claim 1,

wherein the mover includes a pivot mechanism to pivot the first mount,

the pivot mechanism including: a motor; a pinion gear coupled with the motor; and a rack gear to mesh with the pinion gear.

14. An image forming apparatus comprising:

an image forming device to form an image on a plurality of sheets; and

a sheet ejection device to be ejected with the sheets,

the sheet ejection device including: an output tray to be stacked with the sheets, the output tray including: a first mount to mount the sheets; and a second mount abutting on the first mount, the second mount to mount the sheets; and a mover to move the first mount.

15. A sheet stacking method comprising:

stacking a plurality of sheets on a first mount and a second mount; and

moving the first mount.