JP3934098B2 - Sheet material feeding device - Google Patents

Description

  The present invention relates to a sheet material feeding apparatus, and more particularly to a support structure for a roller used in the apparatus.

  In an image forming apparatus such as a printer, a copying machine, or a facsimile machine, a transfer process is performed in which a visible image formed on a latent image carrier such as a photoconductor is transferred onto a transfer material made of a sheet material such as plain paper. In the process, a feeding device for feeding the selected transfer material toward the transfer position is used.

  The feeding device includes a cassette that accommodates the transfer material, a feed roller that is disposed near the feed position of the transfer material in the cassette and is rotatable in the feed direction, and a separation for separating the fed transfer materials one by one. There is an example in which a main part is configured by a mechanism and a registration roller and a guide member that guides a transfer material toward the registration roller.

  In general, the feeding roller of the feeding device having the above-described configuration is generally supported rotatably by a metal rotation shaft. For this reason, although it depends on the outer diameter, the inertial mass is increased and the driving force is increased. In view of this, in order to reduce the weight of the rotating shaft, a configuration using a pipe shaft has also been proposed (for example, Patent Document 2).

JP-A-5-13442 JP 58-21010 A

  However, since the rotating shaft itself is made of metal, the cost required for materials and processing increases.

  In particular, the feed roller is made of a material such as rubber so as to ensure a frictional relationship with the transfer material, and in order to ensure frictional contact with the transfer material, transfer is performed regardless of the size of the transfer material. It is arranged so as to face the central portion in the width direction of the transfer material in the axial direction of the rotation shaft, which is a position where it can contact the material. On the other hand, the drive source of the rotating shaft is often arranged outside the width region of the transfer material, and the axial length of the rotating shaft is usually longer than the width of the transfer material. For these reasons, it is desirable to ensure bending rigidity using metal.

  FIGS. 5A and 5B are diagrams for explaining the flexural rigidity. FIG. 5A shows the case where the metal rotation shaft P1 is used, and FIG. 5B shows the case where the resin rotation shaft P2 is used. Yes.

  In FIG. 5, when the transfer material S placed on the cassette is in contact with the feeding roller P3 and has the same pressure (the force indicated by the symbol F in FIG. 5), the metal rotation shaft P1 is applied. In comparison, the resin rotary shaft P2 having a smaller bending rigidity is more easily bent in the direction of receiving the pressure (F). A metal is desired as the material of the rotating shaft in order to secure the flexural rigidity and secure the feeding friction force of the transfer material S and the positional accuracy between the drive members. Cost increases.

  An object of the present invention is to provide a configuration that does not cause a decrease in rigidity even when an inexpensive material is used in view of the problems in the above-described conventional sheet material feeding device, in particular, the problem of the rotating shaft used for supporting the roller. Another object is to provide a sheet material feeding device.

In order to achieve this object, the invention described in claim 1 is a sheet material feeding device used to feed out a sheet material, and is a plate material that can be moved up and down and opposed to the sheet material. can abut and a roller rotatable feeding direction, the resin of the rotatably the roller is attached centrally to the most bending deformation in the axial direction is increased by the pressure from the sheet material which is location placement in the plate member A rotating shaft, a driving means for driving the rotating shaft located on the end side of the roller in the axial direction of the rotating shaft, and a position near the both ends of the roller and the driving means in the axial direction of the rotating shaft. A support member provided in the vicinity of the axial end of the rotary shaft, and each of the support members is positioned at a position for receiving a force acting from the sheet material in a circumferential direction of the rotary shaft. Has a face Among the supporting members, the supporting members located near both ends of the roller function so as not to change the axial direction of the rotating shaft by supporting from the upper peripheral surface side of the rotating shaft, and the driving means is positioned support member axial end near the rotary shaft is characterized in that a support available-at least the lower circumferential surface side of the axis of rotation.

  According to the first aspect of the present invention, the vicinity of both ends of the roller disposed at the position where the bending deformation is greatest in the axial direction of the rotating shaft and the vicinity of the driving means disposed at the axial end portion separately from this. Are supported by the supporting member, and the supporting member is supported from the upper peripheral surface side of the rotating shaft at both ends of the roller and from at least the lower peripheral surface side in the vicinity of the driving means, so that the occurrence of bending of the rotating shaft is suppressed. In this way, the rotating shaft can be configured with a resin member having low rigidity, and further, at least the lower peripheral surface side is supported in the vicinity of the driving means, so that the bending and bending of the rotating shaft can be eliminated. The positional relationship can be well defined.

  The best mode for carrying out the invention will be described below with reference to the drawings.

  FIG. 1 is a schematic diagram illustrating an image forming apparatus to which a sheet material feeding device according to an embodiment of the present invention is applied.

  The image forming apparatus shown in FIG. 1 is a laser printer that executes an electrophotographic process using laser light as scanning light for forming a latent image. The laser printer 1 has a photoconductive layer on the surface. A rotatable photosensitive drum 2 is provided inside.

  Around the photosensitive drum 2, a charging device 3, an optical device 4, a developing device 5, a transfer device 6, and a cleaning device 7 are arranged for performing an electrophotographic process along the rotation direction indicated by an arrow in the drawing. Yes.

  In the vicinity of the transfer device 6, as will be described in detail later, a device 8 (hereinafter referred to as a paper feed device) 8 for feeding a transfer material S made of a sheet material is provided. A fixing device 9 is provided in the path of the transfer material S that moves after image transfer.

  The optical device 4 shown in FIG. 1 includes a laser light source (not shown), a rotating polygon mirror 4A that scans laser light from the laser light source in the main scanning direction, a plurality of reflecting mirrors 4B, and a scanning lens 4C. Is configured.

  The light emission of the laser light source is controlled by an image signal from the image information processing unit 10 arranged inside the laser printer 1. In addition to handling image signals, the image information processing unit 10 is also provided with a controller board 11 for controlling various electrical components provided in the laser printer 1, and these image information processing units 10 and 10 A drive power supply 12 for the control board 11 is also provided.

  The developing device 5 includes a toner tank 5A that frictionally charges while containing a developer mainly composed of toner, a developer feeding roller 5B fed from the toner tank 5A, and a developer carried on the surface of the photosensitive member. The developing roller 5C supplied toward the electrostatic latent image on the drum 2 is a main part.

  The laser printer 1 having the above configuration forms an image on the transfer material S according to the following procedure.

  When laser light is scanned on the photosensitive drum 2 from the optical device 4 by the image signal from the image information processing unit 10 with respect to the photosensitive drum 2 uniformly charged by the charging device 3, an electrostatic latent image corresponding to the image is obtained. An image is formed. The electrostatic latent image on the photosensitive drum 2 is subjected to visible image processing by the developing device 5 and is transferred by the transfer device 6 to the transfer material S fed from the paper supply device 8.

  The transfer material S to which the image has been transferred is fixed by the fixing device 9 and is discharged through a discharge roller 14 toward a stacker portion 13 provided on the upper surface cover 1A of the laser printer 1.

  In the laser printer 1 shown in FIG. 1, the transfer material S can be manually fed regardless of the paper feeding device 8 side. A sheet feeding tray 15 that can be raised and lowered is provided in the vicinity of the transfer material feeding position in the apparatus 8, and a feeding roller 16 is disposed at a position from the sheet feeding tray 15 toward the transfer position. .

  The paper feeding device 8 can contact the mounting plate 8B dropped into the paper feeding cassette 8A and the transfer material S placed on the mounting plate 8B and can rotate in the feeding direction of the transfer material S. For aligning the feeding roller 8C, the separation pad 8D that abuts the back surface of the fed transfer material S and applies a frictional force in the direction opposite to the feeding direction, and the transfer start position of the image on the photosensitive drum 2. And a resist device 16.

  The mounting plate 8B is divided into two in the feeding direction (arrow direction in the figure) of the transfer material S. Of these, the plate member 8B1 on the front side in the feeding direction is a spring (not shown) disposed on the bottom surface in the feeding direction. It can be pushed upward.

  The feeding roller 8C is made of a material having a relatively large friction coefficient such as rubber, and is supported rotatably by a non-moving portion (not shown) inside the laser printer 1 as shown in detail in FIG. The rotating shaft 8C1 is penetrated by processing such as press fitting along the axial direction, and is integrally attached to the rotating shaft 8C1 by adhesion or welding.

  The rotating shaft 8C1 is made of resin, and the above-described feeding roller 8C is fixed substantially at the center in the axial direction, and a driving gear 18 that can be interlocked with the one-rotation spring clutch 17 is fixed at one end in the axial direction. The one-rotation spring clutch 17 is connected to a rotational driving force with respect to the rotation shaft 8C1 by an actuator of a solenoid 19 disposed in the vicinity thereof.

  The rotating shaft 8C1 is provided with support members 20, 21, and 22 in the axial direction in the vicinity of both ends of the feed roller 8C and in the vicinity of the end portion where the drive gear 18 is located.

  The support members 20, 21, and 22 support the rotary shaft 8C1 at a position where it can receive pressure (corresponding to pressure (F) shown in FIG. 5) acting from the transfer material S side in the circumferential direction of the rotary shaft 8C1. Has a surface.

  Of the support members 20, 21, 22, the support members 20, 21 located in the vicinity of both ends of the feeding roller 8 </ b> C have shaft support surfaces that receive the upper half circumference of the rotating shaft 8 </ b> C <b> 1, and the support member 22 in the vicinity of the end portion is The rotating shaft 8C1 is inserted in a state including the upper half circumference of the rotating shaft 8C1, and at least the lower peripheral surface has a shaft support surface. The rotary shaft 8C1 falls downward due to the reaction force from the support members 20 and 21 receiving the upper half circumference because the lower peripheral surface is supported by the support member 22 located in the vicinity of the end portion of the support members. It is prevented.

  Since the present embodiment is configured as described above, the transfer material S accommodated in the sheet feeding device 8 has one of the two plate members 8B1 of the placement plate 8B pushed up the front end in the feeding direction. As a result, the uppermost one is always in contact with the feeding roller 8C.

  Since the uppermost transfer material S is always in contact with the feed roller 8C, the pressure in the direction in which the rotary shaft 8C1 is pushed up as in the case shown in FIG. 5 (the pressure (F) shown in FIG. 5). Equivalent) works. For this reason, the rotary shaft 8C1 undergoes the largest bending deformation at the center in the axial direction, which is the attachment position of the feeding roller 8C to which the pressure (F) directly acts. However, the support member 20 is located near both ends of the feeding roller 8C. 21 is supported in a state resisting the pressure (F), so that bending deformation is suppressed. Further, since the shaft end portion of the rotating shaft 8C1 is supported by the support member 22 in a state resisting the pressure acting on the rotating shaft 8C1, bending at that portion is suppressed. Moreover, the bending of the rotating shaft 8C1 is also eliminated by the support surface by insertion. As a result, the accuracy of the relative positional relationship between the drive gear 18 positioned at the end of the rotating shaft 8C1 and the gear (not shown) meshing with the driving gear 18 is maintained. The rotation start timing of the rotating shaft 8C1 can be set in accordance with the 17 operation start timing.

  According to the above embodiment, even when the rotation shaft 8C1 is made of resin, the axial direction of the rotation shaft 8C1 is prevented from changing against the pressure at a position where bending deformation is most likely to occur due to the pressure received from the transfer material. The rotary shaft 8C1 can be formed of an inexpensive resin member with a simple configuration in which the support members 20, 21, and 22 are simply provided.

  Next, another embodiment of the present invention will be described below.

  In this embodiment, the hub portion 24 is formed integrally with the rotating shaft used in the support structure using the support members 20, 21, and 22 shown in FIG. 2, and the feeding roller is attached to the hub portion 24. It is characterized by that.

  In FIG. 3, the rotating shaft (for convenience, the same resin as that used in FIG. 2 is used, so that reference numeral 8C1 is used) is attached to the feeding roller (for convenience, reference numeral 8C ′) at the mounting position of the resin hub. 24 is provided.

  As shown in FIGS. 3 (B) and 3 (C), the hub portion 24 includes a flange portion 24A capable of facing and abutting against both ends in the axial direction of the feeding roller 8C ′, and a column portion 24B formed between the flange portions 24A. It is a resin molded part provided with a hub curved surface portion 24C, and is integrally formed with a part of the rotating shaft 8C1.

  Of the hub portion 24, the hub curved surface portion 24 </ b> C is a single portion that can abut against the inner peripheral surface of the feeding roller 8 </ b> C ′ except for a part in the circumferential direction and prevent deformation of the roller cross section. The hub curved surface portion 24 </ b> C is a single portion that abuts against the inner peripheral surface of the feeding roller 8 </ b> C ′ with which the hub curved surface portion 24 </ b> C is not in contact to prevent deformation of the roller cross section at that portion.

  Unlike the embodiment shown in FIG. 2, the feeding roller 8C ′ is configured as a hollow roller having a hollow portion with an inner diameter matched to the radius of curvature of the hub curved surface portion 24C of the hub portion 24, and the inner peripheral surface of the hollow portion is formed as a flange portion 24A. It is press-fitted so as to be positioned between them.

  In such a configuration, when the rotary shaft 8C1 is molded, the hub portion 24 is integrally molded at a position where the feeding roller 8C 'is attached in the axial direction.

  The feeding roller 8 </ b> C ′ is inserted and fixed between the flanges 24 </ b> A of the hub portion 24.

  According to this example, a cavity is formed inside the feed roller 8C, and the support 24B and the curved hub surface 24C are each formed as a single piece in the hub portion 24, not the core body. The amount of material used for the rotating shaft 8C1 including the 8C ′ and the hub portion 24 can be reduced, and in the hub portion 24, the fluidity of the resin during molding is improved by the shape of each portion. Formability can be improved.

  Next, still another embodiment of the present invention will be described with reference to FIG.

  This embodiment is characterized in that the rotary shaft supported by using the support members 20, 21, and 22 shown in FIG. 2 is used for raising / lowering control of the mounting plate 8B in the paper feed cassette 8A.

  In FIG. 4, the plate member 8B1 positioned in the front in the feeding direction among the divided mounting plates 8B is given a habit of being pushed up by the coil spring 25 disposed on the lower front surface in the feeding direction indicated by an arrow.

  At both ends in the width direction of the plate member 8B1 along the axial direction of the rotating shaft 8C1, protrusions 8B2 formed toward the feeding roller 8C side are formed.

  On the other hand, the plate member 8B1 is pushed down to the bottom surface of the paper feed cassette 8A (see FIG. 1) at a position facing the protrusion 8B2 of the plate member 8B1 on the rotating shaft (for convenience, the reference numeral 8C1 shown in FIG. 2 is used). A cam 26 having a shape capable of being formed is integrally formed.

  When the cam 26 interferes with the projection 8B2 and pushes down the plate member 8B1, the leading edge of the transfer material S fed by the feed roller 8C is held by a paper feed roller (not shown) and continuously fed. Is obtained, and the feeding roller 8C completes one rotation by this time. As a result, when the transfer material S is not fed out, the plate member 8B1 is pushed down so that the transfer material S does not come into contact with the feed roller 8C.

  Since the present embodiment is configured as described above, when the transfer material S is not fed out, the cam member 26 on the rotating shaft 8C1 interferes with the protruding portion 8B2 of the plate member 8B1, so that the plate member 8B1 is pushed down, and the feeding roller. The contact between 8C and the transfer material S is released.

  On the other hand, when the feeding roller 8C starts to rotate, the amount of interference between the cam 26 and the protrusion 8B2 is reduced, and accordingly, the plate member 8B1 is pushed up by the bias of the coil spring 25, and the transfer material S contacts the feeding roller 8C. It comes out in contact.

  According to the present embodiment, since the member for raising and lowering a part of the mounting plate is formed on the rotary shaft 8C1 itself, it is not necessary to provide a special raising and lowering member, and the number of parts can be reduced. Further, since the feeding roller 8C and the transfer material S are in contact with each other only during feeding, it is possible to prevent uneven wear of the feeding roller 8C and wavy deformation of the transfer material S, which are likely to occur when they are always in contact. it can.

  In addition, this invention is not restricted to the said Example, A various change is also possible within the range of a summary. For example, in the above-described embodiment, the case where the transfer material S is a feeding target has been described. However, since a sheet material may be used, a feeding device for a sheet-like document may be used.

It is a schematic diagram for explaining an example of an image forming apparatus to which a sheet material feeding device according to an embodiment of the present invention is applied. It is a perspective view for demonstrating the structure of the principal part of the sheet | seat material feeding apparatus by this invention Example. It is a figure for demonstrating the principal part of the sheet material feeding apparatus by other Example of this invention, (A) is a fragmentary sectional view, (B) is shown by code | symbol BB in (A). FIG. 6C is a perspective view in which only the rotating shaft and the hub portion shown in FIG. It is a perspective view of the principal part for demonstrating the other Example of this invention. It is a typical perspective view for demonstrating the prior art example and its malfunction of a sheet material feeding apparatus, (A) shows the case where a rotating shaft is metal, (B) shows the case where a rotating shaft is resin. Each is shown.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Laser printer which is one of image forming apparatuses 2 Photosensitive drum which is a latent image carrier 8 Paper feed device equivalent to a sheet material feeding device 8A Paper feed cassette 8B Placement plate 8B1 One plate member 8B2 Protruding portion 8C, 8C 'Feeding roller 8C1 Rotating shaft 18, 18' Drive gear 20, 21, 22, 22 'Support member 24 Hub portion 24B Strut portion 24C Hub curved surface portion 26 Cam S Corresponding to sheet material Transfer material

Claims (1)

A sheet material feeding device used for feeding a sheet material,
A sheet supply material on which sheet material can be placed and moved up and down,
A roller capable of abutting against the sheet material and rotatable in the feeding direction;
A resin-made rotating shaft that is freely rotatable with the roller attached to the central portion where the bending deformation is greatest in the axial direction due to the pressure acting from the sheet material placed on the plate member;
Driving means for driving the rotating shaft located on the end side of the roller in the axial direction of the rotating shaft;
A support member provided in the vicinity of both ends of the roller in the axial direction of the rotating shaft and in the vicinity of the axial end of the rotating shaft where the driving means is located;
Each of the support members has a shaft support surface of the rotary shaft at a position where the force acting from the sheet material is received in the circumferential direction of the rotary shaft, and among the support members, the support members located near both ends of the roller Functions so as not to change the axial direction of the rotating shaft by supporting from the upper peripheral surface side of the rotating shaft, and the supporting member in the vicinity of the axial end of the rotating shaft where the driving means is located sheet feeding apparatus, characterized in that the support available-at least the lower peripheral surface.

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