AUTO-DOCUMENT FEEDER AND DOCUMENT FEEDING METHOD

Abstract

An auto-document feeder includes: a document placing section on which an original document is placed; a sheet detection sensor configured to detect the original document, length in a feeding direction of the original document being first length larger than second length; a length detection sensor configured to detect the length of the original document while the original document is fed; a first feeding path for feeding the original document to a reading section for reading an image of the original document; a second feeding path for feeding the original document to the reading section, the second feeding path being different from the first feeding path; a switching section configured to selectively switch the first feeding path and the second feeding path; and a control section configured to divert, with the switching section, the original document to the first feeding path if the sheet detection sensor detects the original document.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority from: U.S. provisional application 61/393,336, filed on Oct. 14, 2010 and Japanese Patent Application No. 2011-201386 field on Sep. 15, 2011; the entire contents all of which are incorporated herein by reference.

FIELD

Embodiments described herein relate generally to an auto-document feeder and a document feeding method for feeding an original document to an image reading apparatus.

BACKGROUND

As an image reading apparatus including an auto-document feeder used in an image forming apparatus or the like, there is known an image reading apparatus that includes two sheet feeding paths. In reading plural original documents, the image reading apparatus diverts the original documents to be read to the two sheet feeding paths to improve productivity of the reading.

An image reading apparatus including an auto-document feeder performs reading of an original document after detecting the size of the original document with a first sensor on a tray on which the original document is placed and a second sensor in a sheet feeding path.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional schematic diagram of an image reading apparatus according to a first embodiment;

FIG. 2 is a block diagram of a control system for an auto-document feeder according to the first embodiment;

FIG. 3 is a flowchart for explaining sheet feeding by the auto-document feeder according to the first embodiment;

FIG. 4 is a flowchart for explaining the sheet feeding by the auto document feeder according to the first embodiment;

FIG. 5 is a flowchart for explaining normal feeding of an original document in the auto-document feeder according to the first embodiment; and

FIG. 6 is a flowchart for explaining sheet feeding by an auto-document feeder according to a second embodiment.

DETAILED DESCRIPTION

According to an embodiment, an auto-document feeder includes a document placing section on which an original document is placed. A sheet detection sensor configured to detect the original document placed on the document placing section, length in a feeding direction of the original document being first length larger than second length. A length detection sensor configured to detect the length in the feeding direction of the original document while the original document is fed. A first feeding path for feeding the original document placed on the document placing section to a reading section for reading an image of the original document, a distance from the length detection sensor to the reading section in the first feeding path being larger than the first length. A second feeding path for feeding the original document placed on the document placing section to the reading section, the second feeding path being different from the first feeding path. A switching section configured to selectively switch the first feeding path and the second feeding path. A control section configured to divert, with the switching section, the original document to the first feeding path if the sheet detection sensor detects the original document. An original document contains one or more sheets having the same or different sized sheets.

Embodiments of the present invention are explained below with reference to the accompanying drawings.

First Embodiment

A first embodiment is explained with reference to FIGS. 1 to 5.

FIG. 1 is a cross-sectional schematic sectional view of an image reading apparatus according to the first embodiment.

An image reading apparatus 100 includes a scanner 110, which is an image reading section, and an ADF (auto-document feeder) 10 configured to feed an original document G to the scanner 110. The scanner 110 includes a READ document glass 110a, a platen glass 110b of a document placing table, and an optical mechanism 110c. The optical mechanism 110c optically reads an image of the original document G traveling on or passing over the READ document glass 110a. Alternatively, the optical mechanism 110c is moved by a not-shown driving means along the platen glass 110b in an arrow A direction (see FIG. 1) and optically reads an image of the original document G placed on the platen glass 110b. The scanner 110 includes a photosensor 110d, such as a CCD (Charge Coupled Device), CMOS(Complementary Metal Oxide Semiconductor), CIS(Contact Image Sensor), or the like, configured to photoelectrically convert a light signal from the optical mechanism 110c into an electric signal.

The auto-document feeder 10 includes a document tray 11, which is a document placing section, a pickup roller 12 configured to pick up the original document G from the document tray 11, a separating and feeding roller 13 configured to prevent the original document G from being doubly fed (that is, to feed one original document at a time, not feed multiple documents simultaneously), and a registration roller 14 configured to align the leading end of the original document G picked up from the document tray 11 and fed.

The document tray 11 includes a sheet detection sensor 21. The sheet detection sensor 21 is provided in a position on the document tray 11 where, if an original document, the length in a feeding direction of which is a first length, is placed on the document tray 11, the sheet detection sensor 21 detects the original document but, in the case of an original document, the length in the sheet feeding direction of which is second length smaller than the first length, the sheet detection sensor 21 does not detect the original document. For instance, the first length is maximum length in a feeding direction of an original document that the auto-document feeder 10 can feed.

For example, as the original document, the length in the sheet feeding direction of which is the first length, an original document of the A3 size paper is conceivable. As the original document, the length in the sheet feeding direction of which is the second length, an original document of the A4 size paper is conceivable. Of course, other differently sized papers are possible.

The auto-document feeder 10 includes two feeding paths: an OUT path 16, which is a first feeding path spanning from the registration roller 14 to the scanner 110, and an IN path 17, which is a second feeding path spanning from the registration roller 14 to the scanner 110.

In a document feeding path before branching from the document tray 11 to the OUT path 16 and the IN path 17, a length detection sensor 22 configured to detect the length in a feeding direction of the original document G and a width detection sensor 23 configured to detect the width, which is the length in a direction orthogonal to the feeding direction of the original document G, are provided. The length detection sensor 22 detects the length of the original document G in the feeding direction according to time until the trailing end of the original document G is detected after the leading end of the original document G is detected.

In the OUT path 16, a distance from the length detection sensor 22 to the READ document glass 110a, which is a reading position for the original document G, is larger than the first length of the original document. Since the length from the length detection sensor 22 to the READ document glass 110a is larger than the first length, the length in the feeding direction of the original document G can be detected while the original document, the length in the sheet feeding direction of which is the first length is fed through the OUT path 16. The IN path 17 is different from and typically shorter than the OUT path 16. The length from the length detection sensor 22 to the READ document glass 110a is different from and typically smaller than the first length.

The auto-document feeder 10 includes a pre-reading roller 50 configured to feed the original document G passed through the OUT path 16 or the IN path 17 to the READ document glass 110a of the scanner 110, a post-reading roller 51 configured to discharge the original document G from the READ document glass 110a, a pre-paper discharge roller 52, a paper discharge roller 53, and a paper discharge tray 56. A CIS (Contact Image Sensor) 60 is provided between the post-reading roller 51 and the pre-paper discharge roller 52. The CIS 60 can be provided, for example, in a feeding path reaching from the pre-paper discharge roller 52 to the paper discharge roller 53.

On the READ document glass 110a, the optical mechanism 110c reads an image on a front surface, which is a first surface, of the original document G traveling on the glass surface. The CIS 60 can read an image on a rear surface, which is a second surface, of the original document G traveling to pass the READ document glass 110a.

An empty sensor 70 configured to detect presence or absence of the original document G is arranged above the document tray 11 on a side where the original document G is acquired. A registration sensor 71 configured to detect that the original document G reaches the registration roller 14 is arranged between the separating and feeding roller 13 and the registration roller 14. In the OUT path 16, the registration roller 14 and a paper timing sensor OUT 72, which is a first timing sensor, configured to detect driving timing for an intermediate OUT roller 18 are arranged. In the IN path 17, the registration roller 14 and a paper timing sensor IN 73, which is a second timing sensor, configured to detect driving timing for an intermediate IN roller 28 are arranged.

A pre-reading sensor 76 is arranged between the pre-reading roller 50 and the READ document glass 110a. A reading sensor 77 is arranged between the post-reading roller 51 and the re-discharge roller 52. A paper discharge sensor 78 is arranged between the pre-paper discharge roller 52 and the paper discharge roller 53.

A paper feeding motor 80 drives to rotate the pickup roller 12 and the separating and feeding roller 13. When the original document G on the document tray 11 is acquired, a pickup solenoid 81 swings the pickup roller 12. A registration motor (RGT motor) 82 drives to rotate the registration roller 14. A gate solenoid 83 operates to switch a gate 40, which is a switching section for the feeding path. On one hand, if the gate solenoid 83 is turned off, the gate 40 pivots in an arrow x direction and diverts the original document G to the OUT path 16. On the other hand, if the gate solenoid 83 is turned on, the gate 40 pivots in an arrow y direction and diverts the original document G to the IN path 17.

An intermediate OUT motor 84 drives to rotate the intermediate OUT roller 18 to rotate. An intermediate IN motor 86 drives to rotate the intermediate IN roller 28 to rotate. A READ motor 87 drives the pre-reading roller 50 to rotate, the post-reading roller 51 to rotate, and the pre-paper discharge roller 52 to rotate. A paper discharge motor 88 drives the paper discharge roller 53 to rotate.

A block diagram of a control system 120 mainly for the auto-document feeder 10 is shown in FIG. 2. A main body control section 121 configured to control an entire image forming apparatus including the image reading apparatus 100 is connected to the photosensor 110d of the scanner 110 and the CIS 60. The main body control section 121 controls a CPU 130, which is a control section, of the auto-document feeder 10 via an input and output interface 122. The empty sensor 70, the registration sensor 71, the paper timing sensor OUT 72, the paper timing sensor IN 73, the pre-reading sensor 76, the reading sensor 77, and the paper discharge sensor 78 are connected to an input side of the CPU 130. Further, the sheet detection sensor 21, the sheet length detection sensor 22, and the width detection sensor 23 are connected to the CPU 130.

The pickup solenoid 81, the paper feeding motor 80, the RGT motor 82, the gate solenoid 83, the intermediate OUT motor 84, the intermediate IN motor 86, the READ motor 87, and the paper discharge motor 88 are connected to an output side of the CPU 130.

A sheet feeding method by the auto-document feeder according to this embodiment is explained with reference to the flowcharts of FIGS. 3 and 4.

After a power supply is turned on or during return from a standby state, the CPU 130 confirms that the auto-document feeder 10 is closed (Act 1). If the CPU 130 confirms that the auto-document feeder 10 is closed (No in Act 1), the CPU 130 detects outputs of all the sensors and confirms that a paper jam does not exist in the auto-document feeder 10 (Act 2). If a paper jam is detected according to an output of any one of the sensors (No in Act 2), the CPU 130 notifies, for example, the main body control section 121 of the existence of a paper jam. The control section 121 performs display of the paper jam on a display (not shown) of a publicly-known operation panel included in the image forming apparatus and urges a user to perform a jam treatment. On the other hand, if a paper jam is not detected from outputs of all the sensors (Yes in Act 2), the CPU 130 determines whether the original document G is present on the document tray 11.

When the original document G is placed on the document tray 11, the empty sensor 70 is turned on. Therefore, the CPU 130 detects whether the empty sensor 70 is on (Act 3). If the empty sensor 70 is not on (No in Act 3), the CPU 130 returns to Act 1 and determines whether the ADF 10 is closed. On the other hand, if the empty sensor 70 is on (Yes in Act 3), the CPU 130 transmits a document ON signal to the main body control section 121 and determines whether a paper feeding request signal is received from the main body control section 121 (Act 4).

If the paper feeding request signal is received from the main body control section 121 (Yes in Act 4), the CPU 130 determines according to an output of the sheet detection sensor 21 whether the original document G is detected (Act 5). If the paper feeding request signal is not received (No in Act 4), the auto-document feeder 10 changes to the standby state.

If the sheet detection sensor 21 detects the original document G on the document tray 11, this means that the length in the feeding direction of the original document G is the first length.

If the CPU 130 determines that the sheet detection sensor 21 detects the original document G (Yes in Act 5), the CPU 130 turns off the gate solenoid 83 and moves the gate 40 to feed the original document G to the OUT path 16. Thereafter, the CPU 130 turns on the pickup solenoid 81, turns on the paper feeding motor 80, and rotates the pickup roller 12 and the separating and feeding roller 13 to start an operation for feeding the original document G to the OUT path 16 (Act 6).

According to the start of the feeding of the original document G to the OUT path 16, the CPU 130 decides a sheet size of the original document G according to detection results of the length detection sensor 22 and the width detection sensor 23 provided in the feeding path of the OUT path 16 (Act 7).

The CPU 130 drives the RGT motor 82 and the intermediate OUT motor 84 to feed the original document G, the sheet size of which is decided in Act 7, to the READ document glass 110a, which is a reading section, of the scanner 110 (Act 8).

Subsequently, the CPU 130 instructs reading of the original document G fed to the READ document glass 110a (Act 9).

Thereafter, the CPU 130 drives the paper discharge motor 88, discharges the original document G to the paper discharge tray 56, and ends the processing (Act 10).

If the CPU 130 does not determine in Act 5 that the sheet detection sensor 21 detects the original document G (No in Act 5), the original document G is normally fed. In this case, the length in the feeding direction of the original document G on the document tray 11 is the second length, which is smaller than the first length.

In the normal feeding in this embodiment, the original document G is alternately fed to the IN path and the OUT path. A flow for alternately diverting the original document G to the IN path and the OUT path in the normal feeding is explained with reference to a flowchart of FIG. 5.

If the sheet detection sensor 21 does not detect the original document G, when the normal feeding in the auto-document feeder 10 is started, the CPU 130 feeds the original document G to the IN path 17 or the OUT path 16 (Act 16). In this embodiment, a first original document G1 is fed to the IN path 17. In this case, the CPU 130 turns on the gate solenoid 83 and moves the gate 40 to feed the first original document G1 to the IN path 17. Thereafter, the CPU 130 drives the paper feeding motor 80 and starts the feeding of the first original document G1 to the IN path 17.

Subsequently, the CPU 130 determines whether the trailing end of the first original document G1 passes through the registration sensor 71 and the registration sensor 71 changes from ON to OFF (Act 17). If the CPU 130 determines that the trailing end of the first original document G1 passes through the registration sensor 71 (Yes in Act 17), the CPU 130 determines presence or absence of a second original document G2 according to a detection result of the empty sensor 70 (Act 18).

If the CPU 130 determines that the second original document G2 is present (Yes in Act 18), the CPU 130 feeds the second original document G2 to the IN path 17 or the OUT path 16 different from the feeding path to which the first original document G1 is fed (Act 19). In this embodiment, since the first original document G1 is fed to the IN path 17, the CPU 130 feeds the second original document G2 to the OUT path 16. In this case, the CPU 130 turns off the gate solenoid 83 and moves the gate 40 to feed the second original document G2 to the OUT path 16. Thereafter, the CPU 130 drives the paper feeding motor 80 and starts the feeding of the second original document G2 to the OUT path 16.

The processing for diverting the first original document G1 to the IN path 17 and diverting the second original document G2 to the OUT path 16 as explained above to divert plural original documents Gn to the two feeding paths of the IN path 17 and the OUT path 16 ends. Third and subsequent original documents are diverted to the IN path 17 and the OUT path 16 in the same manner considering an immediately preceding original document as the first original document in the flowchart of FIG. 5.

As explained above, in the normal feeding, since original documents are alternately diverted to the IN path 17 and the OUT path 16, before the immediately preceding original document is discharged from the feeding path feeding of the next original document can be started. Therefore, it is possible to efficiently feed the original documents compared with feeding plural original documents using only one feeding path.

According to the embodiment, since a sheet size of an original document is detected even if the original document is an original document which is long in the sheet feeding direction, it is unnecessary to feed the original document to the reading section again after once causing the original document to pass the reading section. If the original document is an original document which is short in the sheet feeding direction, since the original document is diverted to the first feeding path and the second feeding path, it is possible to keep high productivity in reading of the original document.

Second Embodiment

A second embodiment is explained with reference to FIG. 6.

In the following explanation, components that are the same or similar as those in the first embodiment are denoted by the same reference numerals for brevity and signs and only characteristic sections of a second embodiment are explained. In this embodiment, processing performed when a user inputs in advance a mixed document mode for performing reading of plural original documents having various mixed sheet sizes is explained.

FIG. 6 is a flowchart for explaining a sheet feeding method for an auto-document feeder according to this embodiment.

Acts 1 to 3 are the same or similar as those in the flowchart of FIG. 3 in the first embodiment. If the empty sensor 70 is on in Act 3 (Yes in Act 3), the CPU 130 determines whether the mixed document mode is input from the main body control section 121 (Act 21). The instruction of the mixed document mode is performed by the user from, for example, an operation panel of the image forming apparatus. The main body control section 121 receives the input of the mixed document mode. Thereafter, the main body control section 121 transmits the input of the mixed document mode to the CPU 130 of the auto-document feeder 10.

If the CPU 130 receives the input of the mixed document mode in Act 21 (Yes in Act 21), the CPU 130 sets the mixed document mode (Act 22).

When the mixed document mode is set in Act 22, as in Act 4 and subsequent acts in FIG. 3, the CPU 130 controls a feeding method for the original document G according to a detection result of the sheet detection sensor 21 on the document tray 11. Specifically, if the sheet detection sensor 21 detects the original document G (if the original document G has the first length), the original document G is diverted to the OUT path 16. On the other hand, if the sheet detection sensor 21 does not detect the original document G (if the original document G has the second length), as explained above, for example, if there are two or more original documents G, the CPU 130 diverts first and second original documents respectively to the IN path 17 and the OUT path 16 or vice versa referring to the feeding path of the immediately preceding original document.

If the CPU 130 does not receive the input of the mixed document mode in Act 21 (No in Act 21), the original document G is normally fed. The normal feeding is the feeding method explained with reference to the flow chart of FIG. 5 in the first embodiment.

As in this embodiment, the feeding path is determined using a detection result of the sheet detection sensor 21 on the document tray 11 only if the mixed document mode is input from the user. Therefore, during the mixed document mode in which the original documents G having various sheet sizes are mixed, it is possible to select optimum feeding paths for the respective original documents. In the case of feeding of the original document G having a fixed sheet size not in the mixed document mode, it is possible to efficiently feed the original document G by immediately performing the normal feeding.

The several embodiments are explained above. However, these embodiments are presented as examples and are not intended to limit the scope of the invention. These new embodiments can be carried out in other various forms. Various omissions, substitutions, and changes of the embodiments are possible without departing from the spirit of the invention. These embodiments and modifications thereof are included in the scope and the gist of the invention and are included in the inventions described in claims and the scope of equivalents of the inventions.

Claims

1. An auto-document feeder comprising:

a document placing section on which an original document is placed;

a sheet detection sensor configured to detect the original document placed on the document placing section, a length in a feeding direction of the original document being a first length larger thap a second length;

a length detection sensor configured to detect the length in the feeding direction of the original document while the original document is fed;

a first feeding path for feeding the original document placed on the document placing section to a reading section for reading an image of the original document, a distance from the length detection sensor to the reading section in the first feeding path being larger than the first length;

a second feeding path for feeding a different sheet of the original document placed on the document placing section to the reading section, the second feeding path being different from the first feeding path;

a switching section configured to selectively switch between the first feeding path and the second feeding path; and

a control section configured to divert, with the switching section, the original document to the first feeding path if the sheet detection sensor detects the original document.

2. The auto-document feeder according to claim 1, wherein the first length is a maximum length in the feeding direction of the original document that the auto-document feeder can feed.

3. The auto-document feeder according to claim 1, wherein, in the second feeding path, a distance from the length detection sensor to the reading section is smaller than the first length.

4. The auto-document feeder according to any one of claim 1, wherein, if the sheet detection sensor does not detect an original document having the second length smaller than the first length placed on the document placing section, the control section alternately diverts, with the switching section, the original document to the first feeding path and the second feeding path.

5. The auto-document feeder according to claim 1, wherein, if plural documents are placed on the document placing section, the control section receives input of a mixed document mode indicating that an original document, a length in the feeding direction of which is the first length or the second length smaller than the first length, is included and, if the input of the mixed document mode is received, diverts the original documents to the first feeding path or the second feeding path on the basis of a detection result by the sheet detection sensor.

6. The auto-document feeder according to claim 5, wherein, if the sheet detection sensor does not detect the original document having the second length placed on the document placing section, the control section alternatively diverts, with the switching section, the original document having the second length to the first feeding path or the second feeding path.

7. A document feeding method for an auto-document feeder including: a sheet detection sensor provided in a document placing section; plural feeding paths for feeding an original document placed on the document placing section to an image reading section, lengths of the plural feeding paths at least from a length detection sensor to the reading section being different from one another; and a switching section configured to selectively switch the plural feeding paths, the method comprising:

determining whether an original document, the original document having a length in a feeding direction of which is first length larger than second length, is detected by the sheet detection sensor; and

diverting, if the original document placed on the document placing section is detected by the sheet detection sensor, with the switching section, the original document to a first feeding path, a length of which is larger than the first length of the original document, among the plural feeding paths.

8. The method according to claim 7, wherein the first length is a maximum length in the feeding direction of the original document that the auto-document feeder can feed.

9. The method according to claim 7, further comprising receiving, in reading plural original documents, input of a mixed document mode indicating that an original document, length in the feeding direction of which is the first length or the second length smaller than the first length, is included and, if the input of the mixed document mode is received, diverting, with the switching section, at least the original document having the first length to the first feeding path on the basis of a detection result by the sheet detection sensor.

10. The method according to claim 8, wherein

the auto-document feeder includes a second feeding path, and

the method further comprises alternately diverting, with the switching section, the original document to the first feeding path and the second feeding path if the sheet detection sensor does not detect an original document having the second length.