Patent Application
20170015513
Field of the Invention
The present invention relates to a feeding apparatus and an image forming apparatus.
Description of the Related Art
Generally, recent image forming apparatuses, such as a copier, a printer, and a fax machine, include a feeding cassette that is detachably attached to an apparatus main body and accommodates sheets.
There is one type of the feeding cassette including a stacking plate that can be raised and lowered and presses stacked sheets against a feeding roller. A feeding cassette, discussed in Japanese Patent Application Laid-Open No. 2012-56670, is provided with a slidable trailing edge regulating member. The trailing edge regulating member regulates a position of a trailing edge of sheets, which is stacked on the stacking plate, in a feeding direction. Thus, sheets of different sizes can be used. The feeding cassette, discussed in Japanese Patent Application Laid-Open No. 2012-56670, is further provided with a slidable side end regulating member pair. The side end regulating member pair regulates the side end positions of sheets, which is stacked on the stacking plate, in a direction (hereinafter, referred to as a width direction) orthogonal to the feeding direction.
However, the configuration discussed in Japanese Patent Application Laid-Open No. 2012-56670 has the following problem. Specifically, when the feeding cassette is inserted into the image forming apparatus in a state where an amount of sheets stacked on the stacking plate is equal to or more than a full stacked amount (equal to or more than a predetermined amount), a pickup roller might come into contact with the uppermost sheet during the inserting operation, due to an insufficient distance between the pickup roller and the uppermost sheet on the stacking plate.
When the stacking plate comes into contact with the uppermost sheet during the inserting operation of the feeding cassette, the uppermost sheet and the adjacent sheet stop on an upstream side in the insertion direction of the feeding cassette (front side), and thus are not set at proper positions. If a feeding operation of sheet is performed in this state, the position of an image with respect to the sheet might be deviated, and a paper jam might occur due to collision of the sheet with a guide and the like on a conveyance path.
The present invention is directed, in view of the situation described above, to reduction of position deviation of sheet when a feeding cassette is inserted into an apparatus main body in a state where the amount of sheets stacked on the stacking plate is equal to or more than a predetermined amount (a state where an uppermost one of the sheets stacked on the stacking plate is positioned at or higher than a predetermined position). In an example, a CPU controls rotation of a motor based on an insertion detection unit detecting that a feeding cassette is inserted into an image forming apparatus. The CPU rotates the motor in a reverse direction to move a pickup roller to a second position, whereby the pickup roller is temporarily separated from a sheet. Then, the CPU rotates the motor in a normal direction, whereby the pickup roller moves to a first position to be in contact with the sheet again.
According to an aspect of the present invention, a feeding apparatus includes an apparatus main body, a feeding cassette configured to be inserted into and pulled out from the apparatus main body, a stacking member provided to the feeding cassette and configured to have sheets stacked on the stacking member, a feeding member configured to be raised and lowered and to feed the sheets stacked on the stacking member, a regulating member provided on the feeding cassette and configured to move and regulate a position of the sheets stacked on the stacking member, a contact portion provided on the regulating member and configured to come into contact with the sheets stacked on the stacking member, an elastic portion configured to elastically bias the contact portion toward the sheets stacked on the stacking member, a first movement unit configured to raise the feeding member in accordance with an operation of pulling the feeding cassette out from the apparatus main body, and to lower the feeding member in accordance with an operation of inserting the feeding cassette into the apparatus main body, a switching unit that includes a driving source configured to generate driving force and is configured to use the driving force of the driving source to switch a positional relationship between the feeding member and the stacking member between a first positional relationship and a second positional relationship, wherein the feeding member and the stacking member are disposed farther apart from each other in the second positional relationship than in the first positional relationship, and a control unit configured to control, after the feeding member is lowered in response to insertion of the feeding cassette into the apparatus main body and before the feeding member performs a feeding operation of the sheets, the switching unit in such a manner that the positional relationship between the feeding member and the stacking member is switched to the second positional relationship from the first positional relationship, wherein, in a case where an amount of sheets stacked on the stacking member is equal to or more than a predetermined amount, the contact portion is disposed at a position in contact with the sheets stacked on the stacking member, and wherein, in a case where the amount of sheets stacked on the stacking member is smaller than the predetermined amount, the contact portion is disposed at a position not in contact with the sheets stacked on the stacking member.
Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings.
A first exemplary embodiment to which the present invention is applied is described in detail with reference to the drawings.
As illustrated in
A scanner unit 4 is disposed on an upper side of the feeding apparatus 20. Four process cartridges 10 (10Y, 10M, 10C, and 10Bk) are disposed on an upper side of the scanner unit 4. An intermediate transfer unit 5 is disposed on an upper side of the process cartridges 10 (10Y, 10M, 10C, and 10Bk) and faces the process cartridges 10 (10Y, 10M, 10C, and 10Bk). The intermediate transfer unit includes an intermediate transfer belt 6 as well as primary transfer rollers 7 (7Y, 7M, 7C, and 7Bk), a driver roller 8, and a tension roller 9 that are disposed on the inner side of the intermediate transfer belt 6, and a cleaning unit 11. A secondary transfer roller 12 is disposed on the right side of the intermediate transfer unit 5 and faces the driver roller 8. A fixing unit 13 is disposed on the upper side of the intermediate transfer unit 5 and the secondary transfer roller 12. A discharge roller pair 14 and a two-sided-reversing unit 15 are disposed on an upper left side of the fixing unit 13. The two-sided-reversing unit 15 includes a reversing roller pair 16 and a two-sided flapper 17 as a branching unit.
An operation of the image forming apparatus 1 will be described.
The image forming apparatus 1 illustrated in
The sheets S accommodated in a feeding cassette 24 are picked up (fed) by a pickup roller (feeding member) 21, and are separated from each other and conveyed to the registration roller pair 2 by a feed roller 22 and a separation roller 23.
The leading edge of the sheet S, conveyed by the registration roller pair 2, is detected by the top sensor 3. Then, the sheet S is conveyed to a secondary transfer portion T2 with a timing (position of the sheet S) synchronized with the toner image on the intermediate transfer belt 6. The sheet S on which the toner image has been transferred at the secondary transfer portion T2 is conveyed to the fixing unit 13.
At the fixing unit 13, the toner image is fixed on the sheet S by a pressing roller 13a and a heating roller 13b. The sheet S on which the toner image has been fixed is discharged onto a discharge tray 25 in an apparatus upper portion by the discharge roller pair 14.
The feeding apparatus 20 according to the first exemplary embodiment is described with reference to
The feeding apparatus 20 includes the feeding cassette 24 that can be mounted to and pulled out from the image forming apparatus (apparatus main body) 1, the pickup roller 21, the feed roller 22, and the separation roller 23. The sheets S fed by the pickup roller 21 are separated into individual pieces at a separation nip formed of the feed roller 22 and the separation roller 23 in pressure contact with the feed roller 22, and are conveyed to the registration roller pair 2.
The pickup roller 21, the feed roller 22, and the registration roller pair 2 are rotated by driving force from the motor M1. The electromagnetic clutch C transmits or cuts off the driving force from the motor M1 to the pickup roller 21 and the feed roller 22.
As illustrated in
According to the first exemplary embodiment, the feeding cassette 24 can be mounted to and pulled out from the image forming apparatus 1, in a direction orthogonal to the direction in which the sheet S is fed by the pickup roller 21. Upstream and downstream sides in the mounting direction of the feeding cassette 24 are respectively defined as the front and rear sides of the apparatus main body.
As illustrated in
The feeding cassette 24 is further provided with a front side regulating plate 35 and a rear side regulating plate 36 that regulate positions of end portions of the sheet S on the stacking plate 27 in a width direction orthogonal to the feeding direction. The front side regulating plate 35 and the rear side regulating plate 36 are slidable in the width direction, and form a side end regulating member pair. As illustrated in
The feeding apparatus 20 includes a lock mechanism that locks the trailing edge regulating member 31 and the side end regulating member pair at various positions corresponding to the size of the sheet S. As described above, the operation lever 42 that locks and unlocks the front side regulating plate 35 and the rear side regulating plate 36 is provided to the front side regulating plate 35. Thus, the rear side regulating plate 36 serves as a reference position (reference position for forming an image on the sheet S) of the sheet S in the width direction.
Even the sheets S of the same size differ in width (dimension error), and thus a gap might be formed between the side end of the sheets S and the side end regulating member. As illustrated in
A downstream pressing plate 47 is attached to a downstream side of the front side regulating plate 35 in the feeding direction. The downstream pressing plate 47 is elastically biased toward the downstream side in the mounting direction of the feeding cassette 24 by a pressing spring 48 as an elastic member. A sheet pressing portion 47a of the downstream pressing plate 47 can regulate the position of the sheet S in the width direction, at a position on the downstream side of the fed sheet S in the feeding direction. The pressing plate 43 and the downstream pressing plate 47 can integrally move with the front side regulating plate 35 in the insertion and mounting directions of the feeding cassette 24.
The front side regulating plate 35 is provided with an upper pressing plate (contact member) 45. In a case where the amount (height) of the sheets S stacked on the stacking plate 27 is equal to or more than a full stacked amount (predetermined amount) (when the position of the upper most one of the sheets S stacked on the stacking plate 27 is at a position that is equal to or higher than a predetermined position), the upper pressing plate 45 presses the sheets S at a position equal to or higher than the full stacked position. The upper pressing plate 45 is elastically biased toward the downstream side in the mounting direction of the feeding cassette 24 by a pressing spring 46 as an elastic member. A pressing surface 45a of the upper pressing plate 45 presses the sheets S that are equal to or higher than the full stacked position toward the downstream side (toward the rear side regulating plate 36) in the mounting direction. Generally, a mark is formed on the rear side regulating plate 36 so that the user can recognize the full stacked position of the sheets S.
The lowermost surface (lowermost point) of the pressing surface 45a of the upper pressing plate 45 is lower than the lowermost surface of the lowered pickup roller 21 (dashed dotted line illustrated in
A section (clearance h illustrated in
The lower surface of the upper pressing plate 45 is provided with a tapered portion 45b having a tapered shape as viewed in the feeding direction. Thus, when the stacking plate 27 rises and the stacked sheets S come into contact with the upper pressing plate 45, the upper pressing plate 45 can smoothly move in the width direction.
A configuration of a first movement unit is described with reference to
According to the first exemplary embodiment, when the feeding cassette 24 is mounted to the image forming apparatus 1, the pickup roller 21 is at the first position (feeding position). The pickup roller 21 is at the second position (retracted position) when the feeding cassette 24 has been pulled out from the image forming apparatus 1.
The pickup roller 21 held by the holder 30 can be risen and lowered between the first position and the second position about a rotation center 30a of the holder 30. The pressing lever 50 has one end side elastically biased upward in
As illustrated in
The moment M1, which is applied by the release spring 54 to bias the release lever 51 in the anticlockwise direction, is larger than the moment M2, which is applied by the pressing spring 53 to bias the pressing lever 50 in the clockwise direction. Thus, the pressing lever 50 rotates in the anticlockwise direction in
During the operation of mounting the feeding cassette 24 to the image forming apparatus 1, a contact portion 24a of the feeding cassette 24 presses a contacted portion 51b of the release lever 51 against the elastic force of the release spring 54. Thus, the release lever 51 rotates in a direction indicated by an arrow illustrated in
As described above, according to the first exemplary embodiment, the pickup roller 21 mechanically moves from the second position to the first position, in response to the operation of mounting the feeding cassette 24 to the image forming apparatus 1. The pickup roller 21 mechanically moves from the first position to the second position, in association with the operation of pulling the feeding cassette 24 out from the image forming apparatus 1.
A second movement unit 60 is described with reference to
The feeding apparatus 20 according to the first embodiment includes the second movement unit 60. The second movement unit 60 electrically moves the pickup roller 21 between the first and the second positions when the feeding cassette 24 is mounted to the color image forming apparatus 1. As illustrated in
When the CPU 110 rotates the motor M1 in the reverse direction, the slide member 61 moves downward to press one end side of the pressing lever 50 downward, whereby the pressing lever 50 rotates in the anticlockwise direction in
When the CPU 110 rotates the motor M1 in the normal direction, the slide member 61 moves upward to be separated from the pressing lever 50, whereby the pressing lever 50 rotates in the clockwise direction in
An operation is described that is performed when the feeding cassette 24 is mounted to the image forming apparatus 1 in a state where the height of the sheets S stacked on the stacking plate 27 of the feeding cassette 24 is higher than the full stacked position with reference to
As described above, according to the first exemplary embodiment, the contact portion 24a of the feeding cassette 24 presses the release lever 51 in the operation of mounting the feeding cassette 24 to the image forming apparatus 1. Thus, the pickup roller 21 starts move downward from the second position. When the feeding cassette 24 is inserted to a predetermined mounted position in the image forming apparatus 1, the movement of the pickup roller 21 from the second position to the first position is completed.
In the state where the height of the sheets S stacked on the stacking plate 27 is equal to or higher than the full stacked position, the distance (distance C illustrated in
In a case where the pickup roller 21 comes into contact with the uppermost surface of the sheets S before the feeding cassette 24 reaches the predetermined mounted position in the image forming apparatus 1, the positions of the uppermost sheet S and the adjacent sheet S are deviated in an opposite direction of an insertion direction of the feeding cassette 24 (a direction indicated by an arrow illustrated in
The sheets S are biased toward the downstream side in the insertion direction of the feeding cassette 24 by the pressing plates 43, 45, and 47 provided to the front side regulating plate 35. However, the pressing force of the pressing plates 43, 45, and 47 might not be strong enough to support the sheets S. Thus, the sheets S cannot be pressed toward the rear side regulating plate 36. As a result, the position of the sheet S is deviated in the width direction (the opposite direction of the mounting direction of the feeding cassette 24).
Thus, according to the first exemplary embodiment, the CPU 110 operates the second movement unit 60 before the feeding operation of the sheet S is performed. More specifically, the CPU 110 controls the rotation of the motor M1, when the insertion detection unit 55 detects that the feeding cassette 24 is mounted to the image forming apparatus 1. The CPU 110 rotates the motor M1 in the reverse direction to move the pickup roller 21 to the second position to be temporary separated from the sheet S. Then, the CPU 110 rotates the motor M1 in the normal direction to move the pickup roller 21 to the first position to be in contact with the sheet S again.
With the pickup roller 21 temporarily separated from the sheet S by the second movement unit 60, the upper pressing plate 45 presses the sheets S toward the rear side regulating plate 36. Thus, the deviation of the position of the sheets S in the width direction can be corrected.
Then, the feeding operation is performed after the pickup roller 21 is moved again to the first position. Thus, the deviation of the printing position with respect to the sheet S and the paper jam due to the collision of the sheet S with a guide and the like on the conveyance path can be prevented. According to the first exemplary embodiment, the feeding pressure applied by the pickup roller 21 to the sheets S stacked on the stacking plate 27 is set in such a manner that double feed can be prevented even when the amount of the stacked sheets S is equal to or more than the full stacked amount.
As described above, according to the first exemplary embodiment, the deviation of the position of the sheets S due to the operation of mounting the feeding cassette 24 can be corrected before the operation of feeding the sheet S. Thus, a distance between the lower surface position of the pickup roller 21 and the uppermost surface of the stacked sheets S, which is required to be large enough in conventional printers, can be made short. Accordingly, the feeding apparatus 20 and the image forming apparatus 1 can be downsized in the height direction.
According to the first exemplary embodiment described above, the stacking plate 27 rotates about the rotational center 27a. However, the present invention is not limited to this. For example, the present invention may employ a configuration in which the stacking plate is raised by moving in a parallel manner, as in the configuration discussed in Japanese Patent No. 3483319.
According to the first exemplary embodiment described above, the pickup roller 21 is raised and lowered by driving force of the motor M1. Alternatively, the present invention may employ a configuration for raising and lowering the pickup roller 21 by using a solenoid or the like.
According to the first exemplary embodiment, the positions (the first and second positions) to which the pickup roller 21 is moved by the first movement unit are the same as the positions to which the pickup roller 21 is moved by the second movement unit 60. However, the present invention is not limited to this configuration.
A second exemplary embodiment to which the present invention is applied is described with reference to
According to the first exemplary embodiment, the second movement unit 60 raises the pickup roller 21 to temporarily separate the pickup roller 21 from the sheets S before the feeding operation of the sheets S is performed.
According to the second exemplary embodiment, the stacking plate 127 is lowered to separate the pickup roller 21 from the sheets S before the feeding operation of the sheets S is performed. Then, the upper pressing member 45 presses the sheets S toward the rear side regulating plate 36, whereby the positions of the sheets S in the width direction are corrected.
More specifically, according to the second exemplary embodiment, the CPU 110 rotates the motor M2 in a direction opposite to the direction in which the stacking plate 27 is raised. Thus, the stacking plate 27 is lowered from a state illustrated in
The second exemplary embodiment described above can provide the same effect as in the first exemplary embodiment.
According to the first and the second exemplary embodiments described above, the motor M2 dedicated to raising the stacking plate 27 is provided. However, the present invention is not limited to this configuration. The present invention may be applied to a configuration of raising the stacking plate 27 by transmitting the driving force generated by the motor M1, in charge of the rotation of the pickup roller 21 and the like, to the stacking plate 27.
According to the first and the second exemplary embodiments described above, the image forming unit that forms an image on a sheet employs an electrophotographic image forming process as an example. However, the present invention is not limited to the image forming unit employing the electrophotographic image forming process. For example, the image forming unit may employ an inkjet image forming process of discharging ink droplets from nozzles to form an image on a sheet.
While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.
This application claims the benefit of Japanese Patent Application No. 2014-139873, filed Jul. 7, 2014, which is hereby incorporated by reference herein in its entirety.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2014-139873 | Jul 2014 | JP | national |
This application is a Continuation of U.S. application Ser. No. 14/789,854, filed Jul. 1, 2015, which claims priority from Japanese Patent Application No. 2014-139873 filed Jul. 7, 2014, which are hereby incorporated by reference herein in their entireties.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 14789854 | Jul 2015 | US |
| Child | 15277920 | US |
