JP4327032B2 - Paper feed tray, paper feed device, and image forming apparatus - Google Patents

Description

  The present invention relates to a sheet material supply apparatus used in an image forming apparatus such as an electrophotographic copying machine, a printer, a facsimile machine, a printing machine, or a combination of these, and more particularly to a paper feed tray.

In general, a sheet material supply device (paper feeding device) equipped in an image forming apparatus stacks a sheet material on a bottom plate that is surrounded by a tray side wall and is rotatable in the vertical direction. Each sheet is fed one by one from the uppermost sheet material by a sheet feeding roller in contact with the upper surface, and is conveyed from the sheet feeding tray into the image forming apparatus beyond the upper end of the tray side wall.
In such an apparatus, the end of the sheet material stacked on the bottom plate may be wound (curled) depending on the storage environment and the characteristics of the sheet material. In the process of being transported into the forming unit, a paper feed failure such as skew or non-paper feed occurs due to being caught on the side wall of the tray.
Therefore, conventionally, in order to prevent the paper from colliding with the tray side wall, measures have been taken to reduce the height of the side wall located in the sheet material traveling path over the entire width direction of the sheet material. When it is low, the paper separation performance is lowered, and there is a disadvantage that jams such as double feeding / non-paper feeding occur due to the paper entering the paper separation section in a blocked state.
In addition, there is a measure to prevent deformation of the edge of the paper by keeping the environment such as humidity and temperature inside the tray constant. In this case, however, there is a problem in terms of costs associated with installation of a device such as a dehumidifying heater. .
Japanese Patent Laid-Open No. 2001-213528 discloses a stable feeding operation by forming a slope at the front edge of the paper cassette and making the slope angle different between the central portion and the width direction end. Although a sheet material feeding device is disclosed, it is conveyed from the tray into the image forming unit depending on the edge state, the edge state, the material and size of the sheet material, etc. In this process, it is not possible to sufficiently solve the problem that paper feed defects such as skew and non-paper feed occur due to being caught on the side wall of the tray.
JP 2001-213528 A

  The present invention has been made in consideration of the above-described problems, and smoothly conveys the sheet material into the image forming apparatus regardless of the material and size of the sheet material and the end state thereof. It is an object of the present invention to provide a sheet material supply device that enables the occurrence of a skew and prevents the occurrence of a jam due to the catching of the sheet material.

In order to solve the above-mentioned problem, the invention according to claim 1 includes a bottom plate that holds the sheet material in a laminated state, and a front tray side wall that is positioned forward in the conveyance direction of the sheet material on the bottom plate. In the paper feed tray, the front tray side wall has a height difference that is higher at the center than at both ends, and the height of the both ends can be adjusted .
The invention described in 請 Motomeko 2, in the paper feed tray according to claim 1, wherein the central portion is lower than the straight line connecting the nip portion of the feed roller and reverse roller and sheet material top surface on said bottom plate The upper edge of the both end portions is lower than the upper end portion of the central portion .
The invention described in 請 Motomeko 3, in the paper feed tray according to claim 1, a part or the whole of the front tray sidewall, characterized in that it is detachably attached to the tray side wall bodies.
The invention described in 請 Motomeko 4 is in the sheet feeding apparatus having a paper feed tray according to claim 1 or claim 2, wherein.
The invention described in 請 Motomeko 5 is an image forming apparatus having a sheet feeding apparatus according to claim 4, wherein.

According to the onset bright, a bottom plate which holds the sheet material in a laminated state, a front tray sidewalls located in the conveying direction in front of the sheet material on the bottom plate, the sheet feed tray having a to the front tray sidewall When the sheet material is conveyed from the inside of the paper feed tray into the image forming unit, the edge of the sheet material deformed in the falling direction is caught on the side wall of the tray. Therefore, it is possible to prevent paper feeding problems such as skew and non-feeding.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view of a conventional paper feed tray.
This paper feed tray is included in a sheet material supply device (paper feed device) equipped in an electrophotographic image forming apparatus such as a copying machine, a FAX, or a printer, and is provided at a transfer position provided around a photosensitive member or an intermediate transfer member. The transfer paper P that is fed toward is loaded and accommodated. The paper feed tray 1 is disposed on both sides in the width direction (direction orthogonal to the transport direction) of the transfer paper P to be accommodated, and is capable of moving in the width direction of the transfer paper P according to the width direction size of the transfer paper P. Side fences 2 and 3, an end fence 4 that is positioned at the rear end portion in the paper feed direction and presses the end face of the transfer paper in the paper feed direction, and a bottom plate that always holds the transfer paper P in a paper feed position where the transfer paper P can be fed out 5.
FIG. 2 is a schematic view showing a drive mechanism for rotating the bottom plate 5 to undulate. This drive mechanism is attached to the motor 6 provided in the main body of the image forming apparatus, the drive shaft 7 connected to the motor 6, the end of the drive shaft 7, and disposed at the bottom of the bottom plate 5. The rotating arm 8 is used. In this configuration, when the paper feed tray 1 is set in the main body of the image forming apparatus, the motor 6 is driven, and the drive shaft 7 is rotated along with this, so that the rotary arm rotates integrally with the drive shaft 7. 8 rotates the bottom plate 5 to raise it. Thereby, the transfer paper P placed on the bottom plate 5 is held (standby) at the paper feed position. At the paper feeding position, the uppermost surface of the transfer paper P is brought into contact with the calling roller.
In the paper feeding unit (paper feeding device) shown in FIG. 3, the transfer paper P stored in the paper feeding tray is separated and fed one by one. A calling roller 9 (pickup roller), a paper feed roller 10 (feed roller) and a reverse roller 11 (reverse roller) facing each other are provided. When the copy start switch is turned on, paper feed is performed by a paper feed signal. The roller 10 and the calling roller 9 are rotated. The calling roller 9 brought into pressure contact with the upper surface of the transfer paper P with a predetermined pressure is released from the surface of the transfer paper P after the transfer paper P is fed into the nip portion between the paper supply roller 10 and the reverse roller 11. The reversing roller 11 is driven to rotate in the direction opposite to the feeding direction (conveying direction) of the transfer paper P via a torque limiter, and is fed by an initial pressure by a pressure spring and an operating pressure generated by the torque limiter torque. Is in pressure contact.

FIG. 4 is a perspective view showing the configuration of the paper feed tray of the present invention, and the same parts as those in FIGS. In this sheet feeding tray, the height of the upper end portion of the front tray side wall 12 differs between the tray side wall center portion 12a corresponding to the transfer paper center portion and the tray side wall end portions 12b corresponding to both ends in the width direction of the transfer paper. It consists of a certain structure.
That is, in the sheet feeding tray 1 including the bottom plate 5 that holds the sheet material in a stacked state and the front tray side wall 12 that is positioned forward of the sheet material on the bottom plate in the conveying direction, the height of the front tray side wall 12 is In addition, a difference in height is provided between the central portion and both ends in the width direction.
The central portion 12a of the side wall of the tray that is erected almost vertically allows the transfer paper P to be transferred to the nip portion between the feeding roller 10 and the reverse roller 11 when the uppermost portion of the transfer paper P stacked on the bottom plate is conveyed from the calling roller 9. In order to prevent feeding in a block form (double feed state), the transfer sheet is configured to be several millimeters lower than a straight line connecting the uppermost transfer paper and the nip of the feed roller / reverse roller. Both ends of the tray side wall 12b corresponding to both ends in the width direction of the transfer paper project forward at a predetermined inclination angle toward the front in the paper feeding direction, and the upper end edge of the tray side wall both ends 12b is the tray side wall central portion 12a. It is comprised so that it may be several mm lower than the upper end part. As a result, even when the end of the stacked transfer paper is deformed in the falling direction, it is possible to reduce the catch of the end of the transfer paper and the contact with the side wall in the transport process.

FIG. 5 shows the paper feed tray 1 in which a part of the side wall 12 is removable. In other words, this paper feed tray is characterized in that a part or all of the front tray side wall 12 is detachable from the tray side wall body.
A guide 13 having a function of assisting conveyance of the sheet material is bonded to a tray having a height difference in advance on the front side wall 12 with a seal or the like. That is, the front part of the side wall of the tray has a concave part located on both sides of the central part 12a and a central part 12a having a height of about several millimeters from a straight line connecting the top surface of the full-fitted transfer paper and the nip of the feeding roller / reverse roller. And both end portions 12b in a state of being cut out. One surface of the guide 13 having a structure in which an elastic sheet-like resin, metal or the like is bent at a predetermined angle is bonded and fixed to the outer surface of the tray side wall around the both ends 12b. The height of the upper end portion of the guide 13 is configured to be lower by several mm than the upper end portion of the tray side wall central portion 12a.
The height of the front end portion of the tray side wall varies depending on the type and size of the paper. The side wall of the configuration shown in the figure can prevent the occurrence of a non-feed jam even for a sheet material that causes a feeding failure in normal conveyance.
FIG. 6 shows a mechanism for moving the height direction of both ends of the tray side wall. Rails (notches, grooves) for vertically guiding a movable guide wall 15 (a sheet material configured in the same manner as the guide 13 in FIG. 5) on the inner edges of the recesses 12A respectively provided at both ends in the width direction of the front tray side wall 12 ) 12B is provided, and both end edges (protruding pieces that can be fitted in the rail) of the movable guide wall 15 having the function of assisting the conveyance of the sheet material are inserted into the rail 12B. Both ends of the movable guide wall 15 fitted in the rail are fixed to the holes 17 provided on the side wall of the tray by screws 16 and are integrated with the paper feed tray 1.
As described above, the sheet feeding tray of the present invention enables the side wall of the conveyance side tray to be detachable, so that the side wall having the optimum height difference and the conveyance path according to the variation in the type, size, and end shape of the sheet material. Allows you to exchange.
Further, by screwing a side wall movable in the height direction with respect to the paper feed tray 1 of the present invention, an optimum height difference according to variations in the type and size of the sheet material and the end shape can be obtained. This makes it possible to maintain high rigidity.

The perspective view of the paper feed tray of a prior art example. Schematic of a bottom plate and a bottom plate raising mechanism. FIG. 2 is a side sectional view of FIG. 1. FIG. 3 is a schematic view of a paper feed tray having a tray side wall height difference according to the present invention. FIG. 4 is a schematic view of a detachable paper feed tray side wall. FIG. 3 is a schematic diagram of a side wall of a paper feed tray that can move up and down.

Explanation of symbols

P transfer paper, 1 paper feed tray, 2 right side fence, 3 left side fence, 4 end fence, 5 bottom plate, 6 motor, 7 drive shaft, 8 arm, 9 calling roller, 10 paper feed roller, 11 reverse roller, 12 Tray side wall, 13 Removable transport side wall, 14 Rail, 15 Fixing screw

Claims (5)

A bottom plate which holds the sheet material in a laminated state, a front tray sidewalls located in the conveying direction in front of the sheet material on the bottom plate, the paper feed tray wherein the front tray sidewall across its central portion A paper feed tray having a height difference higher than that of the first and second ends, the height of which can be adjusted . The central portion is lower than a straight line connecting the uppermost surface of the sheet material on the bottom plate and the nip portion of the feeding roller / reverse roller, and the upper end edges of the both end portions are lower than the upper end portion of the central portion. The paper feed tray according to claim 1. The paper feed tray according to claim 1, wherein a part or all of the front tray side wall is detachable from the tray side wall body . A sheet feeding device comprising the sheet feeding tray according to claim 1 .   An image forming apparatus comprising the sheet feeding device according to claim 4.

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