JPH11278685A - Sheet accommodating device and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent inferior performance of sheet feeding likely when sheets ranging backward from a pressure contacting member reciprocate at each sheet feeding motion centering on the rotation center of the pressure contacting member and receive a sliding resistance from the sheet receiving surface of the device body. SOLUTION: A sheet accommodating device is to be installed removably on the body of an image forming device, and the body 8 of sheet accommodating device is equipped rotatably with a pressure contacting member 9 on which sheets S are placed, and a sliding member 11 which is slidable and admits placing thereon the rear of the sheets S is coupled using a coupling means with the tail of member 9 about the sheet transporting direction, and the rear of the sheets S is placed on the sliding member, and it is possible to preclude the sheets S from sliding with the device body.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a sheet storage device capable of storing sheets of a plurality of sizes and an image forming apparatus for forming an image by mounting the sheet storage device.

[0002]

2. Description of the Related Art At present, in an image forming apparatus and the like, a sheet cassette is used as a sheet storing means in order to facilitate setting of a recording sheet and easy replacement. Among these sheet cassettes, there is a universal cassette that can store and supply recording sheets of a plurality of sizes such as A5 and B5 in one sheet cassette. The universal cassette has a side end regulating member that regulates the position of the side end of the recording sheet in accordance with the size of the recording sheet, and a rear end regulating member that regulates the position of the rear end of the recording sheet. The regulating member is configured to be movable in a predetermined direction by a user operation.

[0003] The universal cassette is provided with a pressure spring 56 as shown in FIG.
The pressing plate 52 serving as a pressing member is pushed up from below, and the sheet is pushed up toward the sheet feeding roller 57. The sheet is pressed by sheet separation plates or claws 53 on the left and right side end regulating members 55. The half-moon-shaped paper feed roller 57 rotates in the direction of the arrow (counterclockwise), and the sheet is pushed down to obtain a conveying force and is fed in the feeding direction. Then, the sheets are separated and fed one by one from the uppermost sheet by the sheet separating plate 53.

A rear end regulating member 54 is disposed on the floor surface of the rear end of the cassette body 51 in the sheet feeding direction.
Is configured to regulate the rear end. At a side end parallel to the sheet feeding direction, a side regulating member for abutting the side end of the sheet S is arranged.

[0005]

In recent years, there has been a demand that one image forming apparatus can form an image on a larger number of sheets and a larger number of sheets. It is required that a large number of sheets be stored and fed.

However, as the size and number of storable sheets increase, in the case of a large number of long sheets, FIG.
As shown in (2), the sheet does not fit on the press-contact plate and comes to rest on the sheet receiving surface 58 of the cassette body 51, and the sheet pushed down every time the sheet is fed also moves in the K direction around the rotation center of the press-contact plate 52. Therefore, the sliding resistance with the sheet receiving surface of the cassette is received. Further, there is a possibility that the sheet does not rise to a predetermined height and a feeding failure occurs, without obtaining an appropriate pushing force of the pressure contact plate due to sliding resistance.

Further, the rear end regulating member 54 is
As shown in FIG. 11, since the sheet separation plate 53 is attached to the floor surface, the amount of the sheet separation plate 53 hung on the sheet when the sheet stacking amount is large and when the sheet stacking amount is small is different, and stable separation and feeding cannot be performed. There is a possibility that a large number of sheets are fed due to the sheet coming off the sheet separation plate 53.

An object of the present invention is to solve the above-mentioned problems, and an object of the present invention is to provide a sheet storage apparatus and an image forming apparatus using the same so that stable feeding performance and separation performance can be obtained. It is.

[0009]

In order to achieve the above object, the present invention provides a sheet storage device detachably provided in a main body of an image forming apparatus, wherein a sheet is placed on the main body of the sheet storage device. The pressure contact member is rotatably mounted, and a slide member capable of placing a rear portion of the sheet and slidable is connected to a rear portion of the pressure contact member in a sheet conveying direction by a connection means.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of a sheet storage apparatus and an image forming apparatus using the same according to the present invention will be described in detail with reference to FIGS. 1 and 2 are explanatory views illustrating a sheet cassette, FIG. 3 is a cross-sectional explanatory view illustrating a connecting member between a press-contact plate and a plate, and FIGS. 4, 5 and 6 illustrate a rear end regulating member. FIG. 7 is a cross-sectional explanatory view illustrating a rear end regulating protrusion of the sheet cassette.
FIG. 8 is a structural explanatory view illustrating an image forming apparatus, and FIG. 9 is a structural explanatory view illustrating a sheet cassette.

Here, the overall configuration of a cassette as a sheet storage device and the image forming apparatus will be described first, and then the configuration of the sheet cassette will be described.

[Configuration of Image Forming Apparatus] A laser beam printer A which is an example of an image forming apparatus according to the present embodiment.
As shown in FIG. 8, a laser scanner 1 irradiates a drum-shaped electrophotographic photosensitive member with information light based on image information to form a latent image on the photosensitive member, and develops the latent image to form a toner. Form an image. Further, a cassette mounting portion is provided at the lower portion of the apparatus main body, and a sheet cassette B in which a large number of recording sheets S are stacked and stored is detachably mounted on the mounting portion. Then, in synchronization with the formation of the toner image, the sheet is conveyed from the sheet cassette B to the image forming unit 3 by the sheet conveying unit 2, and the sheet after image formation is discharged to the discharge unit 5 via the fixing unit 4.

The image forming means uses an electrophotographic recording system in the present embodiment, and includes a photosensitive drum 3a as an electrophotographic photosensitive member, a primary charging means (not shown), a developing means,
The process cartridge 3 b in which the cleaning means is formed as a cartridge is configured to be detachable from the image forming apparatus A. Then, the photosensitive drum 3a rotates in synchronization with the conveyance of the recording sheet S, and is uniformly charged by the surface charging means, and the information light from the laser scanner 1 is transferred to the photosensitive drum 3a via the exposure unit. Exposure to form a latent image. The toner frictionally charged by the developing means is transferred in accordance with the latent image to form a toner image, and the toner image is applied to a transfer roller 6 as a transfer means by applying a voltage having a polarity opposite to that of the toner image to the recording sheet S. The image is transferred to an image and recorded. The toner remaining on the photosensitive drum 3a after the transfer of the toner image is removed by a cleaning unit.

On the other hand, the conveying means separates and feeds the recording sheets S of the sheet cassette B one by one by the cooperative action of the feed roller 2a and the sheet separating plate 14, and the retard roller 2b driven via a torque limiter. And the feed roller 2c cooperates to reliably separate and feed. The transfer roller pair 2d and 2e and the registration roller pair 2f convey the sheet S to the image forming unit in synchronization with the formation of the toner image. The fixing device 4 applies heat and pressure to fix the transferred toner image, and the sheet S after image fixing is discharged to a pair of discharge rollers 2g and 2h.
To discharge to a discharge section 5 provided in the upper part of the apparatus.

[Structure of Sheet Cassette] Next, a sheet cassette B which is a universal cassette detachably mounted to the image forming apparatus A will be described.

In FIG. 1, a pressure tray mounted rotatably around a shaft 21 on the left and right side walls of the tray 8 as a center of rotation is provided inside a cassette tray 8 which is a cassette body constituting a frame of the sheet cassette B. A pressure contact plate 9 as a member is provided. A pressing spring 1 is provided on a bottom surface of the cassette tray feeding side as an urging unit that abuts on a predetermined position on the back surface of the pressing plate 9 corresponding to the feeding roller 2a.
The pressing plate 9 is urged in the direction of the feed roller 2a by the elastic force of the pressing spring 10. Pressure plate 9
The upper sheet S is pressed by a sheet separating member 14 rotatably attached to the left and right side regulating members 15a and 15b. When the feed roller 2a rotates in the direction of the arrow,
The sheet S is pushed down by the feed roller 2a and is
Feeding force is obtained by the rubber friction of a. Then, the sheet is separated and fed one by one from the uppermost layer by the sheet separating plate 14. Here, in order to obtain stable separation and feeding performance, it is necessary that an appropriate urging force by the elastic force of the pressure spring 10 be transmitted to the sheet S.

Next, a plate 11 as a slide member slidable in the sheet feeding direction with respect to the cassette tray 8 is connected to the rear portion of the cassette tray 8 in the sheet feeding direction via connecting means to the pressure contact plate 9. Have been. A plurality of rotatable rollers 13 are provided on the back of the slide plate 11 so as to contact the bottom of the cassette tray 8. The connecting means has a hook 19 and a connecting member 20, and the connecting member 20 rides on the slide plate 11 in a smooth arc shape centered on the rotation center 21 of the press contact plate 9, as shown in FIG. , Are connected by a hook 19 on the slide plate 11.

In the present embodiment, the connecting member 20 is formed as a single component independent of the press-contact plate 9, but may be formed integrally with the press-contact plate 9.

As shown in FIGS. 1, 4 and 5, on the upper surface of the slide plate 11, a rear end regulating member 12 configured to be movable to an arbitrary position in the sheet feeding direction also serves as reinforcement. Slide shaft 1 via slide guide 22
8 and moves along the slide shaft 18 to an arbitrary position in the feeding direction. Rear end regulating member 1
2 is fixed at a predetermined position by engagement of a ratchet groove on the slide plate 11 (not shown) with a ratchet lever urged by a spring on the rear end regulating member 12, and the rear end position of the sheet S Is definitely regulated.

As shown in FIG. 1, a sheet S is provided at a side end of the cassette tray 8 parallel to the sheet feeding direction.
A right side regulating member 15a as a reference regulating unit that abuts one side end, and a left side regulating member 15b as a movement regulating unit provided so as to be movable in the sheet width direction with respect to the cassette tray 8. The position of the side end of the sheet S is regulated by both regulating means.

In the present embodiment, the side regulating members 15a and 15b are used to feed the sheet on the basis of the center in the sheet width direction. As shown in FIGS. 1 and 9, a pinion gear 16 is rotatably mounted on the bottom surface of the cassette tray 8, and a rack integrally formed on each of the side regulating members 15a and 15b meshes with this gear 16. The two side regulating members 15a and 15b move symmetrically with respect to the center in the sheet width direction. FIG. 9A shows a state in which a wide and long sheet is stored, and FIG. 9B shows a state in which a narrow and short sheet is stored.

In the above construction, the rear end regulating member 12 and both side regulating members 15a, 15b are moved in accordance with the size of the sheet S to be used, thereby regulating the positions of the rear end and side ends of the sheet S. .

Further, as shown in FIG.
The abutment surface of the sheet S with respect to the sheet S is substantially vertical in the lower half, and has a tapered shape in which the upper half is inclined in the feeding direction at an angle α from the vertical position. As shown in FIG. 6, the position of Y is formed by the dimension of the upper surface of the rear end of the sheet + β when the stacking amount of the short sheet is small.

With the above configuration, the sheet S rides on the slide plate 11 having the plurality of rotatable rollers 13, so that even when a large number of sheets S are stacked, the sheet S is fed. The sliding resistance generated by the forward and backward movement is reduced, and the proper urging force on the sheet S is maintained. Also, the slide plate 11 of the connecting member 20
Since the contact surface of the pressing plate 9 is formed in an arc shape centering on the rotation center of the pressing plate 9, the pressing plate 9
Can be smoothly transmitted to the forward and backward movements of the slide plate 11, and the sliding loss at the connecting portion can be eliminated.

Further, by adopting the above configuration, FIG.
, The slide plate 11 and the rear end regulating member 1
When the position of No. 2 is small (FIG. 2A) and large (FIG. 2B) when the sheet stacking amount is small, the position of No. 2 moves rearward. Becomes constant irrespective of the load amount of the sheet, and stable separation and feeding can be performed.

The sheet contact surface of the rear end regulating member 12 has a tapered shape inclined in the feeding direction, and is formed so as to correct the rear end moving position that changes depending on the size of the sheet S. Therefore, the amount of the sheet separating plate 14 applied to the sheet S is constant, and stable separation and feeding performance can be obtained regardless of the size of the sheet.

As shown in FIGS. 1 and 7, the rear end portion of the cassette tray 8 in the sheet feeding direction is symmetrical slightly behind the normal operation position of a long sheet, for example, an A3 or LDR size sheet. The rear end regulating convex portion 17 regulates detachment of the sheet from the sheet separating plate 14 when receiving an impact when the sheet cassette B is attached to or detached from the image forming apparatus A. The shape of the rear end regulating convex portion is also formed in a tapered shape inclined in the feeding direction similar to that of the rear end regulating member 12, and is configured to be detachable in a block shape integral with or separate from the cassette tray 8. .

Also, as shown in FIG.
A slide plate regulating portion 24 for regulating the left, right, up and down positions of the slide plate 11 is provided on the bottom surface of the cassette tray 8.
, And the amount of the sheet separating plate 14 applied to the sheet S is constant, so that stable separation and feeding performance can be obtained.

In this embodiment, an electrophotographic recording system is exemplified as an image forming unit in the image forming apparatus. However, the image forming unit may adopt another recording system, for example, an ink jet recording system or a thermal transfer recording system. It is possible.

[0030]

As described above, since the present invention is constructed as described above, stable separation and feeding performance can be obtained even when a large number of sheets of a large number are stored in a sheet cassette.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a sheet cassette according to a first embodiment of the present invention.

FIG. 2 is a sectional view illustrating the sheet cassette according to the first embodiment of the present invention.

FIG. 3 is a sectional view illustrating a connecting member between the press-contact plate and the plate according to the first embodiment of the present invention.

FIG. 4 is a sectional view illustrating a rear end regulating member according to the first embodiment of the present invention.

FIG. 5 is a sectional view taken along line XX of FIG. 1, illustrating a rear end regulating member according to the first embodiment of the present invention.

FIG. 6 is a sectional view illustrating a rear end regulating member according to the first embodiment of the present invention.

FIG. 7 is a cross-sectional view illustrating a sheet rear end regulating protrusion of the sheet cassette according to the first embodiment of the present invention.

FIG. 8 is a schematic configuration diagram illustrating an image forming apparatus according to the first embodiment of the present invention.

FIG. 9 is a schematic configuration diagram illustrating a sheet cassette according to the first embodiment of the present invention.

FIG. 10 is a diagram of a sheet cassette according to the related art.

FIG. 11 is a diagram of a sheet cassette according to the related art.

[Explanation of symbols]

 A: Image forming apparatus B: Sheet cassette S: Recording sheet 1: Laser scanner 2: Conveying means 2a, 57: Feeding roller 2b: Retard roller 2c: Feed roller 2d, 2e: Conveying roller pair 2f: Registration roller pair 2g, 2h discharge roller pair 3 image forming means 3a photosensitive drum 3b process cartridge 4 fixing means 5 discharge unit 6 transfer roller 7 controller board 8, 51 cassette tray 9, 52 pressure contact plate 10, 56 ... Pressing spring 11 ... Slide plate 12, 54 ... Rear end regulating member 13 ... Roller 14, 53 ... Sheet separating plate 15a, 15b, 55 ... Side regulating member 16 ... Pinion gear 17 ... Rear end regulating protrusion 18 ... Slide shaft 19 ... Hook on slide plate 20 ... Connecting member 21 ... Rotation center of pressure contact plate 22 ... Slurry Dogaido 24 ... slide plate restricting portion 58 ... sheet receiving surface

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Akihiro Higashima Canon Inc. 3- 30-2 Shimomaruko, Ota-ku, Tokyo

Claims (9)

[Claims] 1. A sheet storage device detachably provided in an image forming apparatus main body, wherein a pressure contact member for mounting a sheet on the sheet storage device main body is rotatably mounted, and a rear portion of the pressure contact member in a sheet conveying direction. And a slide member on which a rear portion of the sheet can be placed and slidable by a connecting means. 2. The sheet storage device according to claim 1, wherein the slide member has a rotatable roller that rolls on a floor surface of the apparatus main body. 3. The sheet storage device according to claim 1, wherein an outer surface of the connecting member of the connecting means is in contact with the sliding member on an arc surface centered on a rotation center of the pressing member. 4. The sheet storage device according to claim 1, further comprising a rear end regulating member which is movable on an arbitrary position in a sheet conveying direction and regulates a rear end of the sheet, on the slide member. . 5. The sheet storage device according to claim 4, wherein the rear end regulating member has a tapered shape in which a sheet contact surface is inclined in a sheet conveying direction. 6. The sheet storage device according to claim 1, wherein a convex portion is provided at a rear portion of the apparatus main body in a sheet conveying direction, the convex portion being in contact with a sheet rear end corner. 7. The sheet storage device according to claim 1, wherein a restricting portion for restricting the movement of the slide member in the sheet conveying direction is provided in the apparatus main body. 8. The image forming apparatus according to claim 1, further comprising: urging means for urging the pressing member toward a sheet feeding means provided on the image forming apparatus main body for feeding a sheet. Sheet storage device. 9. A mounting portion for mounting a sheet storage device, a sheet storage device according to any one of claims 1 to 8 mounted on the mounting portion, and a transport for transporting a sheet stored in the sheet storage device. And an image forming unit for forming an image on a conveyed sheet.