JP3369285B2 - Paper feeder - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper feeder for preventing double feeding of supplied image forming paper in an image forming apparatus such as a copying machine, a printer, and a facsimile. Things. 2. Description of the Related Art Usually, an image forming apparatus such as a copying machine includes:
A paper feed cassette for setting a large number of sheets at a time is provided, and a pickup roller for feeding out the set paper is provided on an upper front side (the paper feed side is a front side) of the paper feed cassette, In front of the paper feed cassette, there is provided a paper feed roller pair for feeding the paper fed by the pickup roller into the apparatus. Conventionally, this paper feed roller pair is composed of an upper roller driven by a motor or the like, and a fixed lower roller for preventing double feeding of sheets. Here, the friction coefficient of the upper roller is the largest, the friction coefficient of the lower roller is the second largest, and the friction coefficient between the sheets is set to be the smallest. This is because when a plurality of sheets are fed between the upper and lower rollers, the lower roller is fixed, so the frictional force prevents the lower sheet from advancing, and the upper roller feeds the upper sheet. Proceed in the direction. At this time, since the coefficient of friction between the sheets is the smallest as described above, the upper sheet and the lower sheet are completely separated from each other, and the lower sheet does not advance and double feed is prevented. However, as described above, if the lower roller is fixed at all times, the same portion of the lower roller surface always comes into contact with the upper roller, and only that portion of the lower roller surface wears, causing so-called uneven wear. Then, the contact pressure between the upper and lower rollers is reduced, and the function of preventing double feeding is reduced and further disappears. Therefore, a method has been devised in which the lower roller is rotated little by little by some method to change the portion in contact with the upper roller to prevent uneven wear and maintain the function of preventing double feed for a long period of time. For example, as shown in FIG. 5, a one-way clutch 22 rotatable in only one direction is provided on a support shaft 23 of the lower roller 2a, and a lever 34 provided with a notch 34a is fixed to the one-way clutch 22. The shaft 33 is fitted into the notch 34a of the lever 34. The shaft 33 is fixed to a lever 32, and the lever 32 is further fixed to a substantially L-shaped lever 31 via a shaft (not shown, this shaft is located substantially on the extension of the support shaft 23). One end 31a of this lever 31
Is in contact with the lower part of the lift plate 30 on which the paper 16 is placed, and a spring 35 for urging the lever 31 in a direction for rotating the lever 31 in a direction opposite to the arrow is connected to the other end 31b. The one-way clutch 22 is connected to the lower roller 2 as shown by the arrow.
a is rotated so as to rotate only in the direction opposite to the sheet conveyance direction (for details, see Japanese Patent Publication No. 5-65416). [0005] In FIG. 5, when the lift plate 30 is lowered from the state where the lift plate 30 is rising upward, the lift plate 30 is lifted.
Pushes down the lever 31, and the lever 31 rotates clockwise. When the lever 31 rotates clockwise, the lever 32 also rotates clockwise about a shaft (not shown) fixed to the lever 31 as a rotation axis, and the shaft 33 fixed to the lever 32 rotates in the same direction. I do. Then, the lever 34 in which the shaft 33 is fitted in the notch 34a rotates in the same direction, and the one-way clutch 22 also rotates clockwise. As described above, the one-way clutch 22
Since the lower roller 2a is mounted so as to rotate only in the direction of the arrow, the lower roller 2a also rotates clockwise. In this way, the portion of the lower roller 2a that contacts the upper roller 2b is changed. When the lift plate 30 rises from the state in which the lift plate 30 has descended downward, the one-way clutch 22 rotates counterclockwise, but the lower roller 2a rotates by the function of the one-way clutch 22. It does not move and remains as it is. In this way, the portion that comes into contact with the upper roller 2b is changed little by little, and the occurrence of uneven wear can be prevented. [0006] However, in the above-described method, since a method of pushing with a hard member such as a lift plate is used, the uneven wear of the lower double feed prevention roller is rotated. There is a problem that blocking is likely to occur when preventing the problem. An object of the present invention is to provide a sheet feeder which does not cause blocking when the uneven feeding of a double feed prevention roller is prevented by turning in consideration of the above problems of the conventional sheet feeder. Is what you do. According to the present invention, there is provided a paper feed cassette in which a paper feed side end of a sheet to be placed protrudes from a paper feed side tip of a lift plate, and a paper feeder. A one-way clutch that is provided on the double feed prevention roller side that is not the drive side of the paper feed roller pair, and that rotates the double feed prevention roller only in the direction opposite to the sheet conveyance direction; A rotating member having a protrusion on the side of the sheet cassette and rotatably supported, and a link member connecting the rotating member and the one-way clutch; The sheet is abutted at the sheet feeding side end of the sheet on which the sheet is placed, and the turning member turns,
This is a sheet feeding device driven via a link member. According to the present invention, the paper feed side end of the sheet comes into contact with the projection of the rotating member, and the rotating member rotates, and the rotation of the rotating member causes the rotation member to rotate through the link member. The one-way clutch is driven, and the double-feed prevention roller is rotated only in the direction opposite to the sheet conveying direction by the one-way clutch. As a result, a change in the surface of the double feed prevention roller at which the roller comes into contact occurs. The present invention will be described below with reference to the drawings showing an embodiment thereof. FIG. 1 is a configuration diagram of a copying machine provided with a sheet feeding device according to an embodiment of the present invention. That is, a document placing plate 12 for placing a document to be copied and a document pressing cover 13 for holding down the document placed on the document placing plate 12 are attached to the upper part of the copying machine. An optical unit 11 configured by a light source, a lens, and the like, for forming an optical image of a document is provided. On the lower side of the optical unit 11, a photosensitive drum 5 to which toner is attached by being exposed to an optical image incident from the optical unit 11,
Conveying rollers 3 and 4 for feeding paper to the photosensitive drum 5 and a paper feeding device, a transfer / separation electrode 6 for forming a toner image on the paper fed to the photosensitive drum 5, and formation of a toner image Conveyor belt 7 for conveying the conveyed sheet, a fixing device 8 for fixing the toner image on the sheet conveyed by the conveyor belt 7, a discharge roller 9 for discharging the fixed sheet to the outside of the copying machine, and a discharge roller 9 for discharging the sheet. A paper discharge tray 10 for receiving paper discharged by the paper roller 9 is provided. The above-described paper feeder includes a paper feed cassette 1 for setting paper, a pickup roller 14 for feeding paper from the paper feed cassette 1, and a multi-feed of paper sent by the pickup roller 14. And a roller driving means 15 for driving the upper roller 2b of the pair of paper feeding rollers 2. Here, a mechanism indicated by A and provided between the double feed prevention roller 2a below the paper feed roller pair 2 and the paper feed cassette 1 is a rotating mechanism of the double feed prevention roller 2a in the present invention. . Also, the lift plate 1a of the sheet cassette 1
Is provided such that the paper feed side end 16a of the paper 16 slightly protrudes from the paper feed side tip of the lift plate 1a. FIG. 2 is a view showing a detailed configuration of the above-mentioned rotating mechanism, and FIG. 3 is a perspective view of a part thereof. In FIG. 2, a one-way clutch 22 for rotating the anti-feed roller 2a only in one direction indicated by an arrow (the direction opposite to the sheet feeding direction) is provided at one end of a support shaft 23 of the anti-feed roller 2a. (See FIG. 3), and one end of a link member 21 is connected to an end surface of the one-way clutch 22 by a pin 21a. Link member 2
The other end of the rotating member 20 is connected to one end of the rotating member 20 by a pin 21b.
b. A spring 24 for urging the rotating member 20 in the clockwise direction is provided on a support portion of the pin 20b.
Is attached. The rotating member 20 has a substantially triangular shape, and has a projection 20a formed at one end other than the two ends, and the projection 20a penetrates a hole 26a formed in the frame 26 to supply the rotation. It protrudes to a position where it can abut on the paper feed side end 16a of the paper of the paper cassette 16 (however, in FIG. 2, the lift plate 1a is at the lower position and does not abut). Next, the operation of the sheet feeding apparatus of the above embodiment will be described with reference to FIGS. First, as shown in FIG. 1, in the initial state in which the sheet cassette 1 on which sheets are loaded is mounted in a copying machine, the lift plate 1a of the sheet cassette 1 is moved to the position shown in FIG. 2 or FIG. As shown in the figure, the paper feed side end 16a of the paper 16 is at a position lowered to the lower side, and is in a state separated from the protrusion 20a of the rotating member 20. When the copy operation is started by operating the operation unit (not shown) of the copying machine, the lift plate 1a is lifted upward until it comes into contact with the pickup roller 14 (arrow M1). Then, as shown in FIG.
The paper feed side end 16 a of the paper 16 is the protrusion 2 of the rotating member 20.
0a, and the protrusion 20a is pushed in the direction of arrow M2. At this time, since the paper 16 has flexibility, the protrusion 2
0a is pressed with a soft feeling and no blocking occurs. When the protruding portion 20a is pressed in this manner, the rotating member 2
0 rotates counterclockwise against the urging force of the spring 24. Accordingly, the end of the link member 21 on the pin 21b side moves in the direction of arrow M3, and the link member 21 rotates the one-way clutch 22 in the direction of arrow M4. As described above, the one-way clutch 22 is provided on the support shaft 23 so as to rotate the double-feed preventing roller 2a only in the clockwise direction. By rotating in the direction of arrow M5, the contact portion with upper roller 2b is changed. Next, the lift plate 1a is lifted to a position where the paper 16 can be sent out by the pickup roller 14, and the paper 16 is sent out to the paper feed roller pair 2 side by the pickup roller 14. Then, the paper 16 advances between the upper roller 2b and the double feed prevention roller 2a, and is transported to the transport roller 3 side by the upper roller 2b rotated clockwise by the roller driving means 15. At this time, the double feed prevention roller 2a receives a force to rotate in the counterclockwise direction from the upper roller 2b, but is stopped without rotating by the function of the one-way clutch 22, and even if a plurality of sheets are supplied, Double feed is prevented. Thereafter, as shown in FIG. 4C, the copy operation is completed and the lift plate 1a of the sheet cassette 1 is moved.
Is lowered in the direction of arrow M6, the paper feed side end 16a of the paper 16 is separated from the protrusion 20a. Then, the rotating member 20 is rotated in the direction of returning to the original state by the urging force of the spring 24, that is, clockwise, and the protrusion 20a
Moves in the direction of arrow M7, and the end of the link member 21 on the pin 21b side also moves in the direction of arrow M8, and the link member 21 rotates the one-way clutch 22 in the direction of arrow M9. As described above, since the one-way clutch 22 rotates the double feed prevention roller 2a only in the clockwise direction, the rotation of the one-way clutch 22 does not cause the double feed prevention roller 2a to rotate. The changed contact portion with the upper roller 2b is kept as it is. As described above, each time the lift plate 1a of the paper feed cassette 1 is raised, the paper feed side end 16a of the paper 16 comes into contact with the projection 20a to rotate the rotary member 20, and further link the link. The double feed prevention roller 2 is moved by moving the member 21.
a is rotated little by little, the contact portion with the upper roller 2b can be changed, and uneven wear of the double feed prevention roller 2a can be prevented. In the above embodiment, the link member is constituted by a single plate-like member. However, if the one-way clutch can be rotated in both directions in accordance with the movement of the rotating member, the link member may be replaced by a single plate-like member. It is not limited. In the above-described embodiment, the shape of the rotating member is substantially triangular. However, a protruding portion is provided to abut on the paper feed side end of the sheet. The configuration is not limited to this as long as the clutch can rotate. In the above embodiment, a copying machine has been described as an example. However, the present invention is not limited to this, and may be applied to other image forming apparatuses such as a printer and a facsimile. As is apparent from the above description, the present invention relates to a paper feed cassette in which the paper feed side end of the paper to be placed protrudes from the paper feed side tip of the lift plate. A one-way clutch that is provided on the double feed prevention roller side that is not the drive side and that rotates the double feed prevention roller only in the direction opposite to the sheet conveyance direction, and has a protrusion on the paper feed cassette side, and is rotatable. A rotating member that is supported, and a link member that connects the rotating member and the one-way clutch. The one-way clutch is provided at a paper feed side end of the sheet on which the protrusion of the rotating member is placed. Since it is driven through the link member by being rotated by the rotation of the rotating member, there is an advantage that blocking does not occur when the uneven feeding of the double feed prevention roller is prevented by the rotation. .

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a configuration diagram of a copying machine including a sheet feeding device according to an embodiment of the present invention. FIG. 2 is a side view of the sheet feeding device of the embodiment. FIG. 3 is a perspective view showing a part of the sheet feeding device of the embodiment. FIGS. 4A, 4B, and 4C are side views for explaining the operation in the embodiment. FIGS. FIG. 5 is a side view of a conventional sheet feeding device. [Description of Signs] 1 Paper feed cassette 1a Lift plate 2 Paper feed roller pair 2a Double feed prevention roller 3 Photoconductor drum 6 Transfer / separator 8 Fixing roller 9 Discharge roller 11 Optical unit 12 Original mounting plate 16 Paper 20 times Moving member 20a Projecting portion 21 Link member 22 One-way clutch

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Arihiro Tsunoda 1-2-28 Tamazuko, Chuo-ku, Osaka-shi, Osaka Inside Mita Kogyo Co., Ltd. (56) References JP-A-2-2211035 (JP, A) JP-A-63-300037 (JP, A) JP-A-63-288839 (JP, A) JP-A-59-108745 (JP, U) JP-A-58-34134 (JP, U) JP-A-2-55637 ( JP, U) Japanese Utility Model Hei 4-40076 (JP, U) Japanese Utility Model Utility Model Sho 63-126342 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) B65H 3/52 330 G03G 15 / 00 516

Claims (1)

(57) [Claim 1] A paper feed cassette in which a paper feed side end of a paper to be placed protrudes from a paper feed side tip of a lift plate, and feeds the paper. Paper feed roller pair, and provided on the double feed prevention roller side that is not the drive side of the paper feed roller pair,
A one-way clutch for rotating the anti-double feed roller only in a direction opposite to the sheet conveying direction, a rotating member having a protrusion on the paper cassette side and rotatably supported, A link member connecting the member and the one-way clutch, wherein the one-way clutch is brought into contact with a paper feed side end of the sheet on which the protrusion of the rotating member is placed, and the rotating member is A sheet feeding device characterized in that the sheet feeding device is driven via the link member by rotating.