JP7412967B2 - Sheet feeding device and image reading device equipped with the same - Google Patents

Description

The present invention relates to a sheet feeding device provided in an image reading device.

2. Description of the Related Art In recent years, image forming apparatuses such as copying machines, facsimile machines, and multifunctional machines thereof are equipped with sheet feeding devices. The sheet feeding device described in Patent Document 1 includes a feeding roller and a conveying roller such as a registration roller disposed downstream of the feeding roller in the sheet conveying direction. Further, a sheet non-feed detection means is provided for detecting a non-feed state in which the leading edge of the sheet conveyed by the feed roller has not reached the conveyance roller. When non-feeding of a sheet is detected by the sheet non-feeding detection means, the feeding roller is rotated and then the conveying roller is rotated.

Japanese Patent Application Publication No. 2001-310839

However, in the technique disclosed in Patent Document 1, when non-feeding of a sheet is detected, it is necessary to adjust the timing of starting driving of the conveying roller. In other words, in a situation where the sheet is not being fed, it is difficult to estimate the actual sheet conveyance speed, and it is very difficult to predict the position of the leading edge of the sheet. If the start of drive of the transport roller is extremely delayed compared to the start of drive of the feed roller, the document may be further transported by the feed roller after the leading edge of the document hits the transport roller. There is a risk of buckling the original.

In view of the above, an object of the present invention is to provide a sheet feeding device that can reduce sheet conveyance defects even when non-feeding occurs by the feeding roller.

A typical configuration of the present invention for achieving the above object includes a feed tray on which sheets are stacked; between a feeding section that feeds the feeding section, a feeding position where the feeding section comes into contact with the sheets stacked on the feeding tray, and a retracted position where the feeding section is separated from the sheets stacked on the feeding tray. an arm portion that movably supports the sheet, a feeding portion that feeds the sheet conveyed by the feeding portion to a downstream side in the sheet conveying direction, and a motor that rotationally drives the feeding portion and the feeding portion. , a separating section that presses against the feeding section and separates overlapping sheets; a conveying section that conveys the sheets separated by the feeding section and the separating section to the downstream side in the sheet conveying direction; and the sheets. a first sheet detection unit provided on the downstream side of the feeding unit in the conveyance direction and provided on the upstream side of the conveyance unit in the sheet conveyance direction, the first sheet detection unit configured to detect a sheet; a second sheet detection section that is provided on the downstream side of the conveyance section in the sheet conveyance direction and detects the sheet; and a control section that controls driving of the feeding section and the feeding section. In the sheet feeding device, the control section moves the feeding section from the feeding position to the retreat position based on the first sheet detection section detecting the sheet fed by the feeding section. If the second sheet detecting section does not detect the sheet within a predetermined period of time after the first sheet detecting section detects the sheet, then the A refeeding operation is performed to feed the sheet again by the feeding section, and in the refeeding operation, the control section stops driving the motor while the feeding section is located at the retracted position. , the feeding section is moved from the retracted position to the feeding position .

According to the present invention, it is possible to reduce sheet conveyance defects even when the sheet is not fed by the feeding roller.

A sectional view showing the configuration of an image reading device including a sheet feeding device according to the present invention. A block diagram showing the configuration of a control section of a sheet feeding device according to the present invention A sectional view showing the configuration of a feeding section of a sheet feeding device according to the present invention Flowchart showing feeding operation and re-feeding operation of the sheet feeding device according to the present invention

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a sheet feeding device and an image reading device equipped with the same according to the present invention will be specifically described below with reference to the drawings.

<Sheet feeding device and image reading device>
The configuration of an image reading device including a sheet feeding device according to the present invention will be described with reference to FIGS. 1 and 2. FIG. 1 is a sectional view showing the configuration of an image reading device including a sheet feeding device according to the present invention. FIG. 2 is a block diagram showing the configuration of the control section of the sheet feeding device according to the present invention.

A sheet feeding device 1 included in the image reading apparatus 13 shown in FIG. 1 includes a feeding tray 2 on which originals P in the form of sheets of paper or the like are stacked. It also makes contact with the uppermost document P stacked on the feed tray 2 (on the feed tray), and conveys the abutted document P to the downstream side in the sheet conveyance direction (hereinafter referred to as "downstream side"). It has a feeding roller 3. Furthermore, it has a feeding roller 4 that feeds the document P conveyed by the feeding roller 3 to the downstream side, and a separating section 5 that comes into pressure contact with the feeding roller 4 and separates the document P into sheets one by one. In the sheet conveyance direction, a pre-separation document detection section SS3 for detecting the document P is provided between the feed roller 3 and the feed roller 4.

Further, the sheet feeding device 1 is provided with a separated document detection section SS4, which is a first sheet detection section that detects the document P separated by the feeding roller 4 and the separation section 5. The separated document detection unit SS4 is provided downstream of the feeding roller 4 and upstream of the conveyance roller 6 in the sheet conveyance direction (hereinafter referred to as "upstream side"). Furthermore, a conveyance roller 6 conveys the document P separated by the feed roller 4 and the separation section 5 to the downstream side, and a second sheet detection section provided downstream of the conveyance roller 6 to detect the document P. A conveyed document detection section SS5 is provided.

Further, the sheet feeding device 1 includes a conveyance roller 7 that conveys the document P conveyed by the conveyance roller 6 to the downstream side, and a document image on the first side (front surface) of the document P conveyed by the conveyance roller 7. It has a first reading roller 8 that conveys the document P to the front side image reading section 16 where it is read. Further, a second reading roller 9 transports the original P to a back side image reading unit 17 that reads the original image on the second side (back side) of the transported original P, and a second reading roller 9 ejects the transported original P to an ejection tray 10. It has a discharge roller 11. As described above, the sheet feeding device 1 provided in the image reading device 13 reads the image of the document P and conveys it using the configuration described above.

As the configuration of the separation section 5, there are known brake pad separation methods, roller separation methods, and retard roller separation methods. The brake pad separation method is a method in which a friction brake plate is pressed against the feeding roller 4 and the document P is separated by friction. Further, in the roller separation method, a friction roller is used as the friction brake plate of the brake pad separation method. Further, in the retard separation method, the friction roller of the roller separation method is driven in reverse. Generally, the retard separation method is said to have the highest separation performance.

As for the drive configuration, the feed roller 3 and the feed roller 4 are rotated by being transmitted with the rotational drive of a feed motor M1, which is a drive source shown in FIG. The feed roller 3 and the feed roller 4 are connected by a swing arm 12, and the swing arm 12 is rotatably supported on a drive shaft 4a of the feed roller 4. The swing arm 12 is configured to rotate by being driven by a feed-out roller lifting motor M5 shown in FIG.

As the swing arm 12 rotates, the feeding roller 3 moves between a feeding position where it comes into contact with the originals P loaded on the feeding tray 2 and feeding out the originals P, and a feeding position where the originals P are fed away from the originals P loaded on the feeding tray 2. It becomes possible to move between the sending position and the retracted position located above. That is, the feeding roller 3 is configured to be able to move away from the originals P loaded on the feeding tray 2.

An image reading device 13 is provided below the sheet feeding device 1 to read an image on the front surface of the document P conveyed by the sheet feeding device 1. A platen glass 14 is provided above the front image reading section 16 of the image reading device 13 . The front-side image reading unit 16 reads the front-side image of the document P being conveyed on the platen glass 14 .

Further, a platen guide 15 for urging the original P against the platen glass 14 is provided at a position facing the platen glass 14 .

<Control unit>
Next, the configuration of the control section 501 of the sheet feeding apparatus 1 will be described using FIG. 2. The control unit 501 of the sheet feeding apparatus 1 includes a CPU (Central Processing Unit) 502. Further, the control unit 501 includes a ROM (Read Only Memory) 503 in which a control program is stored. Furthermore, the control unit 501 includes a RAM (Random Access Memory) 504, which is an area for temporarily holding control data and a work area for calculations associated with control.

The control unit 501 drives various motors and electromagnetic clutches of the sheet feeding device 1 via each driver IC 201 , 202 , 203 , 204 , and 205 based on signals input from various detection means of the sheet feeding device 1 . Control.

The various detection means include a document set sensor SS1, a final document detection sensor SS2, a pre-separation document detection section SS3, a post-separation document detection section SS4, a transported document detection section SS5, a pre-read sensor SS6, and a discharge sensor SS7.

The various motors include a feeding motor M1, a transport motor M2, a reading motor M3, a feeding tray lifting motor M4, and a feeding roller lifting motor M5. Further, the electromagnetic clutch includes a feed clutch CL1.

The CPU 502 controls the feeding motor M1, the transport motor M2, the reading motor M3, the feeding tray lifting motor M4, the feeding roller lifting motor M5, and the feeding clutch CL1 according to a control program stored in the ROM 503.

Further, the CPU 502 of the sheet feeding device 1 performs serial communication with a CPU (not shown) of the image reading device 13, and exchanges control data with the image reading device 13. Note that as long as the image reading device 13 is one in which the control section 501 of the sheet feeding device 1 and the control section (not shown) of the image reading device 13 are integrated, the image reading device 13 may be configured with one CPU without communication. .

<Feeding operation of the feeding section>
Next, the feeding operation and re-feeding operation of the feeding section of the sheet feeding device 1 will be explained using FIGS. 1 to 4. FIG. 3 is a sectional view showing the configuration of the feeding section of the sheet feeding device 1 according to the present invention. FIG. 4 is a flowchart showing the feeding operation and re-feeding operation of the sheet feeding apparatus 1 according to the present invention.

In step S1 of FIG. 4, when a document P is set on the feeding tray 2, the document P is detected by the document set sensor SS1 shown in FIG. As a result, the feed-out roller lifting motor M5 shown in FIG. 2 is driven, and the swing arm 12 is rotated from the retracted position shown by the broken line in FIG. 3 to the feeding position shown by the solid line. Then, the feed roller 3 descends to the feeding position where the document P is fed. Then, the feeding tray 2 is raised via a lifting unit (not shown) by driving the feeding tray lifting motor M4.

After that, when the feeding tray 2 rises to a predetermined feeding position, the feeding roller 3 comes into contact with the document P loaded on the feeding tray 2, and starts driving the feeding motor M1, thereby causing the feeding roller 3 feeds the document P stacked on the feed tray 2. At the same time, the conveyance roller 6 is rotated by starting to drive the conveyance motor M2.

Next, the leading edge of the document P conveyed by the feeding roller 3 passes through the pre-separation document detection section SS3, the feeding roller 4, and the separation section 5. In step S2, when the leading edge of the document P reaches the separated document detection section SS4, the separated document detection section SS4 detects the document P.

Thereafter, in step S3, the swing arm 12 is rotated to the retracted position shown by the broken line in FIG. 3 by driving the feed-out roller lifting motor M5, and the feed-out roller 3 is moved to the retracted position above the feeding position. When the feed roller 3 separates from the document P stacked on the feeding tray 2, the conveyance of the document P is stopped.

This operation of separating the feeding roller 3 from the originals P stacked on the feed tray 2 has the effect of stably transporting the originals P, which tend to buckle, such as thin paper. By releasing the pressing force of the feeding roller 3 from the originals P stacked on the feeding tray 2, it is possible to eliminate the loop caused by buckling of the originals P stacked on the feeding tray 2.

Conversely, since the feeding roller 3 no longer assists in conveying force, the document P is conveyed only by the feeding roller 4. For this reason, transportation failures are likely to occur for documents P that are difficult to transport, such as thick paper.

Thereafter, in step 4, after the separated document detection section SS4 detects the leading edge of the document P, the conveyed document detection section SS5 detects the leading edge of the document P within a predetermined time T1. In that case, the CPU 502 as a control means determines that the document P is being conveyed normally, proceeds to step S5, stops driving the feeding motor M1, and then returns to the operation of step S1.

Conversely, in step S4, the conveyed document detection section SS5 may not detect the leading edge of the document P even after the predetermined time T1 has elapsed since the separated document detection section SS4 detected the leading edge of the document P. In that case, the CPU 502 determines that there is a failure in conveyance of the document P between the separated document detection section SS4 and the transported document detection section SS5, and proceeds to step S6 to move the feed roller 3 to the feeding position again. lower to.

At this time, the drive of the transport motor M2 is not stopped, but the transport roller 6 is kept rotating. On the other hand, when lowering the feeding roller 3 to the feeding position, the driving of the feeding motor M1 is stopped. This prevents the conveying force of the feeding roller 3 from being transmitted to the original P when the descending feeding roller 3 contacts the original P stacked on the feeding tray 2 again.

This is because the document P is inadvertently fed while the feed roller 3 is exhibiting unstable behavior such as bouncing on the document P loaded on the feed tray 2 due to the downward movement of the feed roller 3. This is to prevent the sending operation.

Thereafter, the process proceeds to step S7, and the CPU 502 starts driving the feeding motor M1 again, and starts re-feeding the document P by the feeding roller 3. Thereby, in addition to the conveyance force of the feed roller 4, the conveyance force of the feed roller 3 can also be transmitted to the document P, so that defects in conveyance of the document P can be resolved.

As described above, in this embodiment, after the separated document detection unit SS4 detects the leading edge of the document P in step S2, the document P is not conveyed even if the document P is conveyed for a predetermined time T1 (after a predetermined time has elapsed) by the feeding roller 4 in step S4. The document detection unit SS5 may not detect the leading edge of the document P. In that case, the feeding roller 3 performs a re-feeding operation in step S7 without stopping the driving of the conveying roller 6.

At this time, in step S6, the driving of the feeding roller 3 and the feeding roller 4 is temporarily stopped, and then, in step S7, the feeding roller 3 performs a re-feeding operation again. Further, in step S3, the feeding roller 3 is once separated from the originals P stacked on the feeding tray 2. Thereafter, in step S6, the feed roller 3 is again brought into contact with the document P stacked on the feeding tray 2, and in step S7, the feed roller 3 performs a re-feeding operation.

Further, in step S3, the feeding roller 3 is once separated from the document P stacked on the feeding tray 2, and then, in step S6, the feeding roller 3 is moved again to the document P stacked on the feeding tray 2. bring it into contact with. Thereafter, in step S7, the feeding roller 3 and the feeding roller 4 are started to be driven, and the feeding roller 3 performs a re-feeding operation.

Thereafter, in step 8, the transported document detection section SS5 detects the leading edge of the document P within a predetermined time T2 after the feed roller 3 starts the refeeding operation. In that case, the CPU 502 determines that the conveyance failure of the document P has been resolved by the refeeding operation, and proceeds to step S9 to move the feed roller 3 to the retracted position above the feed position again, and then feed the document P. After stopping the drive of the motor M1, the process returns to step S1.

Conversely, in step S8, the conveyed document detection section SS5 may not detect the leading edge of the document P even after the predetermined time T2 has elapsed since the feed roller 3 started the refeeding operation. In this case, the CPU 502 determines that the conveyance failure of the document P has not been resolved by the re-feeding operation, and proceeds to step S10 to stop the feeding operation, assuming that a delayed JAM has occurred.

Note that after the feed operation of the feed roller 3 is started, the drive of the conveyance motor M2 is not stopped, so the conveyance roller 6 continues the conveyance operation without stopping. Thereby, there is no need to set the driving start timing of the transport roller 6 due to a transport failure of the original P, and it is possible to prevent a transport failure of the original P due to an error in the drive start timing of the transport roller 6.

Further, the refeeding operation by the feeding roller 3 does not need to be performed only once, and may be performed by increasing the number of refeeding operations as appropriate. Furthermore, the refeeding operation performed based on the detection results of the leading edge of the original P by the separated original detection unit SS4 and the transported original detection unit SS5 is performed based on the detection results of the leading edge of the original P by the unseparated original detection unit SS3 and the separated original detection unit SS4. This may be done based on the detection results. Furthermore, both the detection results of the leading edge of the original P by the pre-separation original detection unit SS3 and the post-separation original detection unit SS4, and the detection results of the leading edge of the original P by the post-separation original detection unit SS4 and the conveyed original detection unit SS5. It is also possible to perform the refeeding operation by the feeding roller 3 in combination.

In this way, even if the separated document detection unit SS4 provided downstream of the feed roller 4 detects the leading edge of the document P and the document P is conveyed for a predetermined time (T1, T2), There is a case where the conveyed document detecting section SS5 provided in the document P does not detect the leading edge of the document P. In that case, the feeding roller 3 performs the re-feeding operation without stopping the driving of the conveying roller 6 provided on the downstream side of the feeding roller 4. As a result, it is possible to provide the sheet feeding device 1 that eliminates problems caused by the drive start timing of the transport roller 6 and reduces transport defects of the original P.

P...Manuscript (sheet)
SS4...Document detection unit after separation (first sheet detection unit)
SS5...Feeding document detection section (second sheet detection section)
1...Sheet feeding device 2...Feeding tray 3...Feeding roller 4...Feeding roller 5...Separating section 6...Conveyance roller

Claims (3)

A feeding tray for loading sheets;
a feeding unit that abuts the sheets stacked on the feed tray and feeds the abutted sheets to the downstream side in the sheet conveyance direction;
an arm part that supports the feeding part so as to be movable between a feeding position in which it contacts the sheets stacked on the feeding tray and a retracted position away from the sheets stacked on the feeding tray; and,
a feeding section that feeds the sheet conveyed by the feeding section to the downstream side in the sheet conveying direction;
a motor that rotates the feeding section and the feeding section;
a separating section that presses against the feeding section and separates the overlapping sheets;
a conveying section that conveys the sheet separated by the feeding section and the separating section to a downstream side in the sheet conveying direction;
a first sheet detection section provided on the downstream side of the feeding section in the sheet conveyance direction and provided on the upstream side of the conveyance section in the sheet conveyance direction, the first sheet detection section configured to detect a sheet; a sheet detection section;
a second sheet detection section that is provided on the downstream side of the conveyance section in the sheet conveyance direction and detects the sheet;
a control unit that controls driving of the feeding unit and the feeding unit;
In a sheet feeding device equipped with
The control unit moves the feeding unit from the feeding position to the retreat position based on the first sheet detection unit detecting the sheet fed by the feeding unit , and moves the feeding unit from the feeding position to the retracted position , If the second sheet detecting section does not detect the sheet within a predetermined period of time after the detecting section detects the sheet, the feeding section will feed the sheet again while the conveyance section is rotating. performs a re-feeding operation to feed,
In the refeeding operation, the control unit stops driving the motor while the feeding unit is located at the retracted position, and moves the feeding unit from the retracted position to the feeding position. Characteristic sheet feeding device. The predetermined time is a first predetermined time,
If the second sheet detection unit does not detect the sheet by the time a second predetermined time period elapses after starting the refeeding operation, the control unit controls the feeding unit and the feeding unit. The sheet feeding device according to claim 1 , wherein the sheet feeding device stops feeding the sheet. A sheet feeding device according to claim 1 or 2 ,
an image reading unit that reads an image written on the sheet;
An image reading device comprising:

Images