Patent Application
20180037426
The present invention relates to a sheet supporting apparatus for supporting sheets and an image forming apparatus including the sheet supporting apparatus.
In general, image forming apparatuses, such as copying machines and printers, are provided with a sheet feeding cassette that stores sheets used to form images. Positions of the trailing edge and the side edges of the sheets, stored in the sheet feeding cassette, are regulated by regulation plates, which are supported such that the regulation plate can be moved with respect to the sheet feeding cassette. A user moves the regulation plate in accordance with a sheet size, sets sheets in the sheet feeding cassette, and attaches the sheet feeding cassette to an apparatus body.
Conventionally, Japanese Patent Application Publication No. H05-278869 proposes a sheet feeding cassette in which projections are formed at two corner portions of a regulation plate, and concave portions capable of engaging with one of the projections are formed in a cassette body. A user can move the regulation plate by turning the regulation plate to one direction to release the engagement between the one of the projections and one of the concave portions, and position the regulation plate by releasing the turn of the regulation plate to engage the one of the projections with another one of the concave portions.
In the sheet feeding cassette described in Japanese Patent Application Publication No. H05-278869, however, because the engagement between the projection and the concave portion may not be ensured or a user may perform a wrong operation, the regulation plate may be displaced from a proper position. The displacement of the regulation plate from the proper position causes reduction in print precision and occurrence of jam.
According to one aspect of the present invention, a sheet supporting apparatus includes a supporting portion configured to support a sheet, and a regulation unit configured to regulate a position of edge of the sheet supported by the supporting portion, the regulation unit configured to be moved and positioned with respect to the supporting portion. The regulation unit includes a body portion, an engagement portion supported by the body portion, and configured to move between an engagement position at which the engagement portion engages with the supporting portion and a separation position at which the engagement portion is separated away from the supporting portion, and a regulation portion configured to position the engagement portion with respect to the body portion such that the engagement portion is retained at the engagement position.
Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings.
First, a first embodiment of the present invention will be described. A printer 1 according to the first embodiment that serves as an image forming apparatus is an electrophotographic laser-beam printer. As illustrated in
When an image forming instruction is outputted to the printer 1, an image forming process by the image forming portion 6 is started, based on image information data inputted from, for example, an external computer connected to the printer 1 or an image reading apparatus optionally connected to the printer 1. The image forming portion 6 includes a known cartridge 6a including a photosensitive drum 6b, a charger, and a developing roller, a scanner unit 9, and a transfer roller 7.
The scanner unit 9 emits a laser beam to the photosensitive drum 6b, based on inputted image information data. At this time, the photosensitive drum 6b has been charged in advance by the charger, and thus an electrostatic latent image is formed on the photosensitive drum 6b by the laser beam projected thereto. The electrostatic latent image is then developed by the developing roller, and a toner image is formed on the photosensitive drum 6b.
Simultaneously with the above-described image forming process, a sheet that has been stuck on the feeding cassette 2 is fed by the feeding portion 3. The feeding portion 3 includes a pickup roller 3a that feeds sheets, stuck on the feeding cassette 2, and a feed roller 3b and a separation roller 3c that separate the sheets, one by one, fed by the pickup roller 3a. The sheet fed by the feeding portion 3 is conveyed to a registration roller pair 5 by a conveyance roller 4, and abuts a nip of the registration roller pair 5 that is in a stop state. The leading edge of the sheet then becomes parallel to the nip, and thus skew of the sheet is corrected.
The skew-corrected sheet is conveyed toward the transfer roller 7 by the registration roller pair 5, in synchronization with an image formation by the image forming portion 6. The transfer roller 7 is applied with transfer bias, and transfers the toner image formed on the photosensitive drum 6b, onto the sheet. The sheet, on which the toner image is transferred by the transfer roller 7, is then subjected to heat and pressure treatment by the fixing portion 8 constituted by a heating roller 8a and a pressure roller 8b, and thus the toner image is fixed on the sheet. The sheet on which the toner image is fixed is then discharged to a discharge tray 11 by the discharge roller pair 10.
Next, with reference to
The side edge regulation plates 22 and 23 are supported such that the side edge regulation plates 22 and 23 can be moved in a width direction orthogonal to a sheet conveyance direction, and each have a rack-shaped portion which meshes with an interlocking gear 223. Thus, the side edge regulation plates 22 and 23 are structured such that, when the side edge regulation plate 22 is moved, the side edge regulation plate 23 is also moved together with the side edge regulation plate 22, with the aid of the interlocking gear 223 and the rack-shaped portions. The trailing edge regulation plate 24 is structured such that the trailing edge regulation plate 24 can be moved in the sheet conveyance direction and a direction opposite to the sheet conveyance direction (directions indicated by an arrow A) with the aid of a guide 21b formed in the base plate 21a.
The intermediate plate 25 is supported such that a downstream side, in the sheet conveyance direction, of the intermediate plate 25 is swung on the shaft portions 21c and 21c. When the downstream side of the intermediate plate 25 moves upward, a downstream side of the sheets stored in the feeding cassette 2 is pressed against the pickup roller 3a. The intermediate plate 25 is formed not to prevent the movements of the side edge regulation plates 22 and 23 and the trailing edge regulation plate 24 in the whole locus of the swing of the intermediate plate 25.
Next, a structure of the trailing edge regulation plate 24 of the first embodiment will be described in detail with reference to
As illustrated in
In the present embodiment, the first stopper 31 is disposed corresponding to the first pressing portion 27c, and the second stopper 30 is disposed corresponding to the second pressing portion 27d. The structure of the first stopper 31 is substantially the same as that of the second stopper 30, and thus the first stopper 31 will be mainly described. Here, the first stopper 31 is a stopper to position the trailing edge regulation plate 24 at a position corresponding to any one of the standard sizes, and the second stopper 30 is a stopper to position the trailing edge regulation plate 24 at a position corresponding to a non-standard size. In
As illustrated in
At an upper end of the first stopper 31, a through hole 31c is formed at a position corresponding to a through hole 26a formed in the body portion 26, as illustrated in
In addition, the first stopper 31 also includes a pressed portion 31a in contact with the first pressing portion 27c, as illustrated in
Next, the operation of the trailing edge regulation plate 24 will be described. In a case where a user sets sheets in the feeding cassette 2, the user first places sheets, such as sheets with a predetermined size, on the base plate 21a and the intermediate plate 25, and then positions the side edge regulation plates 22 and 23 by moving the side edge regulation plates 22 and 23 to the side edges of the sheets. In the present embodiment, the above-described predetermined size of the sheets is a standard size.
The user then operates the holding portion 27b and moves the trailing edge regulation plate 24. In a state of the trailing edge regulation plate 24 before the user operates the trailing edge regulation plate 24, the first stopper 31 and the second stopper 30 are urged toward the base plate 21a of the cassette body 21 by the urging force of the coil springs 32 and 42. When the trailing edge regulation plate 24 is positioned at a position corresponding to the standard-size sheets, the trailing edge regulation plate 24 is positioned by the first stopper 31 engaging with the positioning hole 29. When the trailing edge regulation plate 24 is not positioned at the position corresponding to the standard-size sheets, the trailing edge regulation plate 24 is positioned such that a plurality of teeth formed at an end of the second stopper 30 engage with a rack-shaped portion formed on the cassette body 21 of the feeding cassette 2.
When the holding portion 27b is pivoted upstream or downstream in the sheet conveyance direction from a neutral position, the first pressing portion 27c and the second pressing portion 27d, which are pivoted with the holding portion 27b, are pivoted in a direction indicated by an arrow A1 or a direction indicated by an arrow A2, as illustrated in
When the movement of the trailing edge regulation plate 24 is completed, the user returns the holding portion 27b to its original position and engages the engagement pin 31b of the first stopper 31 with the positioning hole 29. That is, the first stopper 31 is positioned at the engagement position. With this, the trailing edge regulation plate 24 is positioned.
Commonly, when predetermined-size sheets are successively used, the trailing edge regulation plate 24 needs not to be moved. For that reason, it is preferable that the trailing edge regulation plate 24 is fixed not to be moved, when the sheet size is not changed, and that the fixed state of the trailing edge regulation plate 24 can be released only when the sheet size is changed.
In the present embodiment, the first stopper 31 positioned at the engagement position can be fixed to the female screw 26b of the body portion 26 with the screw 33, as illustrated in
Thus, since the positional displacement of the trailing edge regulation plate 24 can be prevented by reliably fixing the trailing edge regulation plate 24 with respect to the base plate 21a of the cassette body 21, print precision can be improved and the occurrence of jam can be reduced. In addition, fixing the first stopper 31 with respect to the body portion 26 by the screw can achieve simplification, downsizing, and cost reduction of the sheet supporting apparatus, compared to a configuration in which a plurality of female screws are disposed at, for example, positions corresponding to standard sizes of sheets in the feeding cassette 2.
In addition, when the sheet size is often changed, the trailing edge regulation plate 24 is used without the screw 33 that fixes the trailing edge regulation plate 24. This can improve usability.
In addition, although the first stopper 31 is fixed at the engagement position with the screw 33 and the female screw 26b in the present embodiment, other fixing methods may be employed. For example, the first stopper 31 may be fixed to the body portion 26 with another fixing component, such as a snap ring.
Next, a second embodiment of the present invention will be described. In the second embodiment, the first stopper 31 of the first embodiment can be fixed by another configuration. Thus, the same component as that of the first embodiment is omitted in the drawings, or described with the same symbol given to the drawings.
As illustrated in
Here, the first stopper 31 is positioned at the engagement position such that a predetermined gap SP is present between a top surface 131d of the first stopper 31 and a top plate 126c of the body portion 126, and is moved from the engagement position toward the separation position so as to reduce the gap SP. When a user fixes the trailing edge regulation plate 124, the user first positions the first stopper 31 at the engagement position and then inserts the spacer 34 into the insertion hole 126a of the body portion 126. With this configuration, the above-described gap SP between the first stopper 31 and the body portion 126 is filled with the spacer 34.
That is, the spacer 34 is placed in the gap SP, and thereby regulates the movement of the first stopper 31 from the engagement position to the separation position. Thus, because the first stopper 31 is fixed with respect to the body portion 126 so that the first stopper 31 is retained at the engagement position, and because the positional displacement of the trailing edge regulation plate 24 can be prevented, print precision can be improved and the occurrence of jam can be reduced. In addition, because the spacer 34 can be attached and detached without using any tool, fixing and releasing the trailing edge regulation plate 124 can be easily performed, and thus usability can be further improved.
The fixing of the trailing edge regulation plate with the spacer 34 in the present embodiment may be combined with the fixing of the trailing edge regulation plate with the screw 33 in the first embodiment, to achieve a configuration in which the trailing edge regulation plate can be fixed by using any method of spacer fixing and screw fixing. With this, usability can be improved.
Next, a third embodiment of the present invention will be described. In the third embodiment, the first stopper 31 of the first or the second embodiment can be fixed by another configuration. Thus, the same component as that of the first or the second embodiment is omitted in the drawings, or described with the same symbol given to the drawings.
As illustrated in
When a user fixes the trailing edge regulation plate 224 with respect to the cassette body 21 (see
In order to move the trailing edge regulation plate 224 with respect to the cassette body 21, a user operates the concave portion 35a through the through hole 26a (see
Thus, fixing and releasing of the trailing edge regulation plate 124 to and from the body portion 26 can be easily performed without providing any additional member. This improves usability. In addition, the form of the concave portion 35a may be modified as appropriate to pivot the lock lever 35 by using only a dedicated tool. With this configuration, specific and limited users can fix or release the trailing edge regulation plate 224.
Although the present invention is applied, in any of the embodiments described above, to the trailing edge regulation plate that regulates the position of the trailing edge of the sheets, the present invention is not limited to this. For example, the present invention may be applied to the side edge regulation plates 22 and 23 that regulate the positions of the side edges of the sheets.
Also, although the description is made, in any of the embodiments describe above, for the case where the electrophotographic printer 1 is used, the present invention is not limited to this. For example, the present invention may also be applied to an ink-jet image forming apparatus that forms images on sheets by injecting ink from a nozzle.
Also, although the description is made, in any of the embodiments described above, for the configuration in which the first stopper 31 is locked at the engagement position, the present invention is not limited to this. For example, the first stopper 31 may be locked at a position between the engagement position and the separation position as long as the first stopper 31 is not pulled out of the positioning hole 29.
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. 2016-152178, filed Aug. 2, 2016, which is hereby incorporated by reference wherein in its entirety.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2016-152178 | Aug 2016 | JP | national |
