JP2008081263A - Paper feed cassette and image forming apparatus including the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a paper feed cassette and an image forming apparatus including the same, storing both tab sheets and plain paper sheets with the trailing edges aligned with each other without attaching and detaching another member. <P>SOLUTION: This paper feed cassette 7, which may store a plurality of sheets (plain paper sheets or tab sheets P') stacked on an elevating base plate, includes: side cursors 35 for receiving both side parts of stored sheets and aligning the right and left sides of the sheets; and an end stopper 36 for receiving the trailing ends of the sheets and aligning the trailing edges of the sheets, wherein the side cursor 35 and the end stopper 36 are removable, and the fitting positions thereof are replaced with each other. In the case of storing tab sheets P' in the paper feed cassette 7, both side parts of the tab sheet P' are received on side cursor 35 and the end stopper 36, and the trailing end of the tab sheet P' is received by the other side cursor 35. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet feeding cassette capable of accommodating both a tab sheet having a tab at the rear end edge and a normal sheet having no tab with the rear end edge aligned, and an image forming apparatus provided with the same. It is.

  2. Description of the Related Art Image forming apparatuses such as copying machines, printers, and facsimile machines are provided with a paper feed cassette that can be attached to and detached from the main body and can store a large number of sheets in a stacked manner. This paper feed cassette is provided with an end stopper that can receive a part of the trailing edge of the stored sheet and align the trailing edge of the sheet so as to be slidable.

  By the way, the types of sheets used in the image forming apparatus tend to increase year by year, and in recent years, there is a demand from the market that it is desired to pass a tab sheet having a tab at the trailing edge.

  However, some tab sheets are provided with tabs in addition to the central portion in the width direction (the portion received by the end stopper). Therefore, such tab sheets are not aligned at the rear end position by the rear end presser. There was a problem in that the rear edge was uneven, and this caused paper feeding failure. In general, sheets of various sizes can be accommodated in the sheet cassette, and both side portions of the sheets accommodated therein are received by a pair of side cursors slidable in a direction perpendicular to the both side portions. Although the width direction is aligned, the end stopper is generally provided at the center in the width direction of the sheet in order to avoid interference with the side cursor receiving both side surfaces of the minimum size sheet. Its width dimension is limited.

Therefore, in Patent Document 1, when the tab sheet is accommodated in the paper feed cassette, an end guide member having a length corresponding to substantially the entire width of the rear end edge of the tab sheet is attached to the end stopper, and the rear end edge of the tab sheet is provided. Proposals have been made to receive both the rear end guide member and the end stopper.
JP 2000-229732 A

  However, in the configuration proposed in Patent Document 1, the rear end guide member is a separate member from the end stopper and is not used for ordinary sheets other than the tab sheet. At this time, the image forming apparatus must be packaged with the image forming apparatus or installed in the image forming apparatus, which causes inconvenience in handling.

  And depending on the size of the rear end guide member which is a separate member, it is difficult to store and handle it, which places an excessive burden on the user.

  SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and its objective is to feed a tab sheet and a normal sheet that can be accommodated with their rear ends aligned without attaching or removing a separate member. It is an object of the present invention to provide a cassette and an image forming apparatus including the cassette.

  In order to achieve the above object, according to the first aspect of the present invention, a plurality of sheets can be stacked and accommodated on a bottom plate that can be moved up and down, and the right and left sides of the sheets are received by receiving both sides of the accommodated sheets. The side cursor and the end stopper are detachable in a sheet feeding cassette comprising a side cursor for aligning the sheet and an end stopper for receiving the trailing edge of the sheet and aligning the trailing edge of the sheet. It is characterized in that it can be replaced.

  According to the second aspect of the present invention, there is provided an end stopper that can receive and stack a plurality of sheets on a bottom plate that can be moved up and down, and that receives the rear end of the stored sheet and aligns the rear end edges of the sheet. In the sheet feeding cassette, the end stopper is composed of two rear end pressing portions having different widths that are perpendicular to each other, and the rear end of the sheet is moved to the two rear ends by changing the mounting angle of the end stopper. It is characterized in that it is received by any one of the end pressing portions.

  According to a third aspect of the present invention, there is provided an image carrier that forms a latent image, a developing device that develops the latent image formed on the image carrier as a toner image, and a paper feed cassette that accommodates a plurality of sheets. An image forming apparatus comprising: a transfer device that transfers the toner image onto a sheet fed from the paper feed cassette; and a fixing device that fixes the toner image transferred onto the sheet by the transfer device. The paper cassette is constituted by the paper feed cassette according to claim 1 or 2.

  According to the first aspect of the present invention, when the ordinary sheet other than the tab sheet is stored in the sheet feeding cassette, the rear end of the ordinary sheet is received by the end stopper as usual and the rear end of the ordinary sheet is aligned. it can. When the tab sheet is stored in the sheet cassette, the mounting positions of the end stopper and the side cursor are exchanged with each other, and the rear end of the tab sheet is extended over the entire width with the side cursor having a longer length than the end stopper. By receiving, the rear ends of the tab sheets can be aligned. Therefore, it is possible to store both the normal sheet and the tab sheet in the sheet feed cassette with their rear ends aligned without attaching or detaching another member, and to prevent the occurrence of sheet feeding failure.

  According to the second aspect of the present invention, when the ordinary sheet other than the tab sheet is accommodated in the sheet feeding cassette, the rear end of the ordinary sheet is received by the rear end receiving portion having a narrow end stopper, and The rear ends can be aligned. When the tab sheet is accommodated in the sheet cassette, the end angle of the end stopper is changed, and the rear end of the tab sheet is received over the entire width by the rear end receiving portion having a long length. The edges can be aligned. Therefore, it is possible to store both the normal sheet and the tab sheet in the sheet feed cassette with their rear ends aligned without attaching or detaching another member, and to prevent the occurrence of sheet feeding failure.

  According to the invention described in claim 3, in the image forming apparatus provided with the sheet feeding cassette, the effects of the invention described in claims 1 and 2 can be obtained, and the tab sheet and the ordinary sheet can be obtained without attaching / detaching another member. Any of these can be accommodated in the paper feed cassette with the rear ends aligned, and the paper feed operation from the paper feed cassette to the image forming unit can be performed stably.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

  FIG. 1 is a perspective view of a laser beam printer as an embodiment of an image forming apparatus according to the present invention, and FIG. 2 is a front sectional view of the laser beam printer.

  First, the basic configuration of the laser beam printer 1 will be described with reference to FIGS. 1 and 2. The laser beam printer 1 includes a box-shaped apparatus main body 1a. As shown in FIG. An inclined concave paper discharge tray 32 is provided at the center of the upper surface of the paper, and an operation display section 34 is disposed beside it. In addition, an openable and closable manual feed tray 8 (shown in an open state is shown in FIG. 2) is provided at the upper part of the front surface of the apparatus main body 1a (the front side in FIG. 1 is the front), and at the lower part of the apparatus main body 1a. A rectangular box-shaped paper feed cassette 7 that can be pulled out to the front side is provided.

  Next, the internal structure of the laser beam printer 1 will be described with reference to FIG.

  The laser beam printer 1 forms an image on a sheet based on image data transmitted from a terminal (not shown) while conveying the sheet along a conveyance path L provided in the apparatus main body 1a. The transport path L includes a horizontal portion L1 extending substantially horizontally from the front to the rear (right to left in FIG. 2) in the apparatus main body 1a, and a vertical portion L2 rising substantially vertically from the end of the horizontal portion L1. It is comprised by the side view substantially L-shape.

  Further, the laser beam printer 1 includes a paper feeding unit 2 provided at a lower portion of the apparatus main body 1a, an image forming unit 3 provided at a substantially central portion in the apparatus main body 1a above the paper feeding unit 2, The fixing device 4 disposed behind the image forming unit 3, the concave paper discharge unit 5 provided on the upper surface of the apparatus main body 1a above the fixing device 4, the horizontal part L1 of the conveying path L, and the present invention. The switchback unit 6 is provided between the sheet cassette 7 and the sheet cassette 7.

  The sheet feeding unit 2 stores sheets and feeds the sheets toward the image forming unit 3 and includes the sheet feeding cassette 7 according to the present invention.

  Here, the paper feed cassette 7 has a rectangular box shape with an open upper surface, and has a function of feeding sheets (not shown) stacked and accommodated therein one by one. As shown, in the state where it is mounted in the apparatus main body 1a, it is located below the horizontal portion L1 of the transport path L as shown.

  The sheet feeding cassette 7 includes a lift plate 9 that contacts and separates from the inner bottom surface, a bottom plate 10 that moves up and down in conjunction with the contact and separation operation of the lift plate 9, and a front end of the lift plate 9 (downstream in the sheet feeding direction). 2) and a lift drive shaft 11 that is attached in the vicinity of the lift plate 9 to rotate the lift plate 9 in the direction of the arrow in FIG. 2, and supports the vicinity of the rear end of the bottom plate 10 (upstream end in the sheet feeding direction). A shaft 12 is provided.

  In addition, the sheet feeding unit 2 is brought into contact with the vicinity of the leading end of the uppermost sheet in the sheet feeding cassette 7 to pick up the sheet, and the taken-out sheet is sent to the horizontal part L1 of the conveying path L. After the feed roller 14, the retard roller 15 that is driven in the opposite direction to the feed roller 14 to return the multi-feeded sheet, the plurality of paper feeding rollers 16, 17, 18, and the fed-out sheet are temporarily held. In addition to the registration rollers 19 that are supplied to the image forming unit 3 at a predetermined timing, a pickup roller 20 that takes out the paper placed on the manual feed tray 8 is provided. Here, the retard roller 15 is provided on the paper feed cassette 7 side.

  The image forming unit 3 forms an image on a sheet supplied from the paper feeding unit 2, and is an image carrier that is rotatably disposed at a substantially central portion in the front-rear direction of the horizontal portion L 1 of the conveyance path L. A photosensitive drum 21, a primary charger 22, a developing device 23, a transfer roller 24 and a cleaning device 25 disposed around the photosensitive drum 21, a laser scanner unit (LSU) 26, a toner hopper 27, and the like disposed above them. I have.

  The fixing device 4 is for fixing the toner image transferred onto the sheet in the image forming unit 3 to the sheet, and includes a heating roller 28 and a pressure roller 29 that rotate while being pressed against each other. Yes.

  Further, the paper discharge unit 5 is for discharging the sheet on which the toner image is fixed in the fixing device 4 to the outside of the apparatus main body 1a, and is provided in the middle of the vertical portion L2 of the conveyance path L. And a paper discharge roller 31 provided at the end of the vertical portion L2 and the paper discharge tray 32 for stacking sheets discharged to the outside of the apparatus main body 1a.

  The switchback unit 6 is used when an image is formed on both sides of a sheet. The switchback unit 6 is provided in another conveyance path L ′ disposed below the horizontal portion L1 of the conveyance path L and in an appropriate position thereof. A plurality of transport rollers 33 are provided.

  Next, an image forming operation of the laser beam printer 1 having the above configuration will be described.

  For example, when a print start signal is transmitted to the laser beam printer 1 from a terminal such as a personal computer (personal computer), in the image forming unit 3, the photosensitive drum 21 is driven in a direction indicated by an arrow (clockwise) in FIG. ) And the surface thereof is uniformly charged to a predetermined potential by the primary charger 22. When a laser beam based on the image data transmitted from the terminal is output from the laser scanner unit 26 and irradiated onto the photosensitive drum 21, an electrostatic latent image is formed on the photosensitive drum 21. Then, the electrostatic latent image formed on the photosensitive drum 21 is developed by the developing device 23 using toner as a developer to be visualized as a toner image.

  At the same time, in the paper feeding unit 2, the sheets stored in the paper feeding cassette 7 are picked up one by one from the uppermost one by the pickup roller 13, and are conveyed by the feed roller 14 and the paper feeding rollers 16, 17, 18. After being sent to the horizontal portion L1 of L and temporarily put into a standby state by the registration roller 19, it is supplied to the image forming portion 3 at a predetermined timing synchronized with the toner image on the photosensitive drum 21. In the paper feed cassette 7, the lift plate 9 is rotated in a direction away from the inner bottom surface, so that the bottom plate 10 is raised to a predetermined height position corresponding to the number of sheets stacked thereon, The uppermost sheet stacked on the bottom plate 10 is picked up by the pickup roller 13. When forming an image on the sheets stacked on the manual feed tray 8, the sheets are picked up one by one by the pickup roller 20, and sent to the horizontal portion L 1 of the conveyance path L by the paper feed rollers 16 and 18. .

  In the image forming unit 3, the sheet supplied to the transfer nip between the photosensitive drum 21 and the transfer roller 24 constituting the transfer device is conveyed while being pressed against the photosensitive drum 21 by the transfer roller 24. The toner image on the photosensitive drum 21 is transferred to the surface (transfer surface). The sheet onto which the toner image has been transferred is conveyed to the fixing device 4, and is heated and pressed in the process of being sandwiched and conveyed between the heating roller 28 and the pressure roller 29 in the fixing device 4. Get fixed. The toner remaining on the surface of the photosensitive drum 21 after transfer of the toner image to the sheet (transfer residual toner) is removed by the cleaning device 25.

  Thus, the sheet on which the toner image is fixed on the surface by the fixing device 4 is conveyed upward by the conveying roller 30 along the vertical portion L2 of the conveying path L, and is provided on the upper portion of the apparatus main body 1a by the paper discharge roller 31. The paper is discharged and stacked on the discharged paper discharge tray 32.

  The above is a series of operations when an image is formed on one side of a sheet. When an image is formed on both sides of a sheet, a sheet on which a toner image is fixed on one side by a fixing device 4 is conveyed by a conveyance roller 30. After the sheet is fed to the vertical portion L2 of the conveyance path L, the sheet is switched back by feeding the conveyance roller 30 in the reverse direction to be fed to another conveyance path L ′. The sheet is conveyed forward (to the right in FIG. 2) along the conveyance path L ′ by the plurality of conveyance rollers 33 provided in the conveyance path L ′, and the sheet is conveyed by the sheet feeding rollers 16, 17 and 18. When the sheet is fed again to the horizontal portion L1 of the conveyance path L, the front and back of the sheet are reversed, and thereafter, the toner image on the photosensitive drum 21 is transferred to the surface of the sheet (the other surface on which no image is formed) by the same operation as described above. ) And the toner image is fixed on the sheet in the fixing device 4, images are formed on both sides of the sheet. The sheet on which images are formed on both sides in this way is conveyed upward along the vertical portion L2 of the conveying path L by the conveying roller 30 in the same manner as described above, and is discharged to the discharge tray 32 by the discharge roller 31.

  Next, an embodiment of the paper feed cassette 7 according to the present invention will be described.

<Embodiment 1>
FIG. 3 is a schematic plan view of a paper feed cassette containing ordinary sheets, and FIG. 4 is a schematic plan view of a paper feed cassette containing tab sheets.

  As shown in FIG. 2, the paper feed cassette 7 is provided with a bottom plate 10 that can be turned up and down about a shaft 12. The bottom plate 10 has a large number of ordinary sheets of various sizes. P (see FIG. 3) or tab sheet P ′ (see FIG. 4) is stacked and placed. As shown in FIG. 4, each tab sheet P 'has a tab Pa' at the rear edge, and this tab Pa 'is provided at a different position in the width direction in each tab sheet P'.

  By the way, as shown in FIG. 3, when the ordinary sheet P is stored in the sheet feeding cassette 7, a pair of left and right side cursors for aligning the left and right directions of the ordinary sheet P on both sides of the ordinary sheet P. 35 are slidable in the width direction (vertical direction in FIG. 3) so that they can be separated from each other, and these side cursors 35 are brought into contact with both sides of the normal sheet P as shown in the figure. The normal sheet P is aligned in the left-right direction.

  Further, an end stopper 36 for aligning the trailing edge of the normal sheet P is provided at the center in the width direction in the paper feed cassette 7 so as to be slidable in the front-rear direction (left-right direction in FIG. 3). As shown in the figure, an end stopper 36 is brought into contact with the rear end of the regular sheet P so that the rear ends thereof are aligned. The end stopper 36 is not provided over the entire width of the rear edge of the normal sheet P for the above-described reason (to avoid interference with the side cursor 35), and is provided in a part in the width direction. The width is set shorter than the length of the side cursor 35. Accordingly, in the end stopper 36, both the tab sheet P ′ shown in FIG. 4 has the tab Pa ′ within the width of the end stopper 36 and the tab sheet P ′ having the tab Pa ′ at a position deviating from the width of the end stopper 36. The edges cannot be aligned.

  Therefore, this embodiment is characterized in that one side cursor 35 and the end stopper 36 can be attached and detached, and their attachment positions can be exchanged with each other.

  Therefore, as shown in FIG. 4, when the tab sheet P ′ is stored in the sheet feeding cassette 7, the attachment positions of the end stopper 36 and the side cursor 35 are exchanged with each other, and both side portions of the tab sheet P ′ are The left side of the tab sheet P ′ is aligned with the other side cursor 35 and the end stopper 36 whose mounting position is changed, and the rear end of the tab sheet P ′ is made substantially full width with the side cursor 35 longer than the end stopper 36. By receiving over, the rear end of the tab sheet P ′ can be aligned.

  With the above configuration, it is possible to store both the normal sheet P and the tab sheet P ′ in the sheet feed cassette 7 with the rear ends aligned without attaching or detaching another member. Can be prevented. In the laser beam printer 1 shown in FIGS. 1 and 2 provided with such a paper feed cassette 7, the paper feed operation from the paper feed cassette 7 to the image forming unit 3 can be performed stably.

<Embodiment 2>
Next, a second embodiment of the paper feed cassette will be described with reference to FIGS.

  FIG. 5 is a perspective view of a main part of the paper feed cassette that accommodates ordinary sheets, and FIG. 6 is a perspective view of the main part of the paper feed cassette that accommodates tab sheets.

  The present embodiment is characterized in that the end stopper 36 is constituted by two rear end pressing portions 36a and 36b having different widths which are perpendicular to each other, and the mounting angle of the end stopper 36 can be changed.

  Thus, as shown in FIG. 5, when the ordinary sheet P is stored in the sheet feeding cassette 7, the end stopper 36 is arranged so that the narrower rear end receiving portion 36a serves as the rear end of the ordinary sheet P. Install in the direction facing. Then, the normal sheet P is received and aligned by the rear end receiving portion 36 a having a narrow rear end at the end stopper 36.

  On the other hand, as shown in FIG. 6, when the tab sheet P ′ is accommodated in the sheet feeding cassette 7, the mounting angle of the end stopper 36 is changed, and the rear end receiving portion 36 b having the longer length is attached to the tab sheet P ′. Try to face the rear edge. Then, the rear end of the tab sheet P ′ is received over substantially the entire width by the wide rear end receiving portion 36 b of the end stopper 36, and the rear ends of the tab sheet P ′ are aligned.

  Therefore, also in the present embodiment, similarly to the first embodiment, both the normal sheet P and the tab sheet P ′ are stored in the sheet feed cassette 7 with the rear ends aligned without attaching or removing separate members. Therefore, it is possible to prevent the occurrence of paper feed failure. In the laser beam printer 1 shown in FIGS. 1 and 2 provided with such a paper feed cassette 7, the paper feed operation from the paper feed cassette 7 to the image forming unit 3 can be performed stably.

  In the above, the present invention has been described with respect to a laser beam printer and a paper cassette provided therein. However, the present invention is not limited to a printer, and other arbitrary image formation such as a copying machine or a facsimile machine. Of course, the present invention can also be applied to the apparatus and the paper feed cassette provided therein.

1 is a perspective view of an image forming apparatus (laser beam printer) according to the present invention. 1 is a front sectional view of an image forming apparatus (laser beam printer) according to the present invention. FIG. 3 is a schematic plan view showing a state in which ordinary sheets are accommodated in the sheet feeding cassette according to Embodiment 1 of the present invention. FIG. 3 is a schematic plan view showing a state in which the tab sheet of the paper feed cassette according to Embodiment 1 of the present invention is accommodated. It is a principal part perspective view which shows the state which accommodated the normal sheet of the paper feed cassette which concerns on Embodiment 2 of this invention. It is a principal part perspective view which shows the state which accommodated the tab sheet | seat of the paper feed cassette which concerns on Embodiment 2 of this invention.

Explanation of symbols

1 Laser beam printer (image forming device)
DESCRIPTION OF SYMBOLS 1a Device main body 2 Paper feed part 3 Image forming part 4 Fixing device 5 Paper discharge part 6 Switchback part 8 Manual feed tray 9 Lift plate 10 Bottom plate 10a, 10b Bottom plate notch 10c Bottom plate rectangular hole 11 Lift drive shaft 12 shaft 13 Pickup Roller 14 Feed roller 15 Retard roller 16-18 Paper feed roller 19 Registration roller 20 Pickup roller 21 Photosensitive drum (image carrier)
22 Primary Charger 23 Developing Device 24 Transfer Roller (Transfer Device)
25 Cleaning device 26 Laser scanner unit (LSU)
27 Toner hopper 28 Heating roller 29 Pressure roller 30 Conveying roller 31 Discharging roller 32 Discharging tray 33 Conveying roller 34 Operation display section 35 Side cursor 36 End stopper 36a, 36b End stopper rear end pressing section L, L 'Conveying path P Normal sheet P 'Tab sheet Pa' Tab

Claims (3)

A plurality of sheets can be stacked and accommodated on a bottom plate that can be moved up and down, a side cursor that receives both sides of the accommodated sheets and aligns the left and right sides of the sheets, and a sheet that receives the rear end of the sheet In the paper feed cassette comprising an end stopper that aligns the trailing edge of
A sheet feeding cassette characterized in that the side cursor and the end stopper are detachable, and their mounting positions are interchangeable. In a paper feed cassette that can be stacked and accommodated on a bottom plate that can be moved up and down, and that includes an end stopper that receives the rear end of the received sheet and aligns the rear end edge of the sheet,
The end stopper is composed of two rear end pressing portions with different widths that are perpendicular to each other, and the rear end of the sheet is changed to one of the two rear end pressing portions by changing the mounting angle of the end stopper. A paper feed cassette characterized by receiving it. An image carrier that forms a latent image, a developing device that develops the latent image formed on the image carrier as a toner image, a paper feed cassette that stores a plurality of sheets, and a feed from the paper feed cassette An image forming apparatus comprising: a transfer device that transfers the toner image onto the sheet that has been transferred; and a fixing device that fixes the toner image transferred onto the sheet by the transfer device.
An image forming apparatus comprising the paper feed cassette according to claim 1 or 2.

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