JP3929036B2 - Paper feeding device and image forming apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention includes a paper feed roller that feeds a paper while rotating in contact with the paper, a separation member holder supported rotatably about a rotation axis substantially parallel to the rotation axis of the paper feed roller, A separation member held by the separation member holding body, and a pressure member that presses the separation member holding body toward the circumferential surface of the paper feed roller and presses the separation member against the circumferential surface of the paper feed roller And when a plurality of sheets are sent out, a predetermined sheet to be sent out and the other sheets are sent out by feeding the sheet to the pressure contact portion between the sheet feeding roller and the separating member by the rotation of the sheet feeding roller. The present invention relates to a paper feeding device that separates and feeds only predetermined paper.
[0002]
[Prior art]
An image forming apparatus configured as a copying machine, a printer, a facsimile, or a complex machine thereof is provided with a paper feeding device of the above type, and the paper is separated one by one by the paper feeding device, and an image is printed on the paper. Forming is well known in the art. Since the separating member holding body of the sheet feeding device is rotatably supported, it is necessary to support the separating member holding body with a slight play. However, when the separating member holding body is supported in this way, when the sheet passes between the paper feeding roller and the separating member, the separating member holding body vibrates, which may cause abnormal noise.
[0003]
[Problems to be solved by the invention]
SUMMARY OF THE INVENTION An object of the present invention is to provide a paper feeding device that eliminates the above-mentioned conventional drawbacks with a simple configuration, and an image forming apparatus having the paper feeding device.
[0004]
[Means for Solving the Problems]
In order to achieve the above object, according to the present invention, in the sheet feeding device of the type described at the beginning, the elastic member that presses against the separating member holding body and applies a force to the separating member holding body in the rotation axis direction thereof. A paper feeding device provided with a film is proposed (claim 1).
[0005]
In that case, it is advantageous that the elastic film is configured to pressurize the separating member holding body toward each outer side in the paper width direction orthogonal to the transport direction of the fed paper. 2).
[0006]
The paper feeding device according to claim 1 or 2, further comprising a guide for guiding the paper fed by the paper feeding roller, wherein the guide is a pair of papers spaced apart in the paper width direction. The separating member holding body has leg portions that fit into the pair of holes, respectively, and the elastic film is inserted into each of the pair of holes to place the leg portions in the paper width direction. It is advantageous that the pressure is applied toward each outer side (Claim 3).
[0007]
Furthermore, in order to achieve the above object, the present invention includes the sheet feeding device according to any one of claims 1 to 3 and an image forming unit that forms an image on a sheet fed from the sheet feeding device. An image forming apparatus is proposed (claim 4).
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below in detail with reference to the drawings.
FIG. 1 is a schematic cross-sectional view of a printer that is an example of an image forming apparatus. A housing 1 of the image forming apparatus shown here has a housing main body 2 and a door 3 supported by the housing main body 2 so as to be rotatable and openable in the direction of arrow A. A paper feeding device 4 is provided in the door 3, and another paper feeding device 5 is disposed in the housing 1.
[0009]
Further, an image forming means 6 is disposed in the housing 1. The image forming means 6 shown as an example here is a drum-shaped photoconductor 7 that is driven to rotate counterclockwise, and the photoconductor 7 is charged. A charging device 8 that exposes the surface of the charged photoreceptor to form an electrostatic latent image, a developing device 10 that visualizes the electrostatic latent image as a toner image, and the above-described supply device. A transfer device 11 for transferring the toner image on the photoconductor to the paper fed in the direction of arrow B from one of the paper devices 4 and 5, and a cleaning device 12 for cleaning the surface of the photoconductor after the toner image is transferred. Have. The sheet on which the toner image has been transferred is conveyed in the direction of arrow C, and when the sheet passes through the fixing device 13, the toner image is fixed on the sheet. The paper that has passed through the fixing device 13 is discharged onto the paper discharge unit 14.
[0010]
FIG. 2 is an enlarged cross-sectional view of the paper feeding device 4, and the illustration of the door 3 shown in FIG. 1 is omitted in this figure. The paper feeding device 4 shown here has a paper feeding roller 15 supported by a door (FIG. 1) and a paper feeding cassette 16 that is also detachably attached to the door. The sheet support plate 18 is supported so as to be swingable. The paper P is stacked on the paper support plate 18, and the front end of the paper P is moved by the pressure action of a spring 19 provided between the front end side of the paper support plate 18 and the bottom surface of the paper feed cassette 16. It is in pressure contact with the circumferential surface. As will be described later, the paper P is sent in the direction of arrow D by the paper feed roller 15 rotating in the direction of the arrow about the rotation axis X at the center thereof.
[0011]
As shown in FIGS. 3 and 4, on the downstream side of the paper support plate 18 in the paper delivery direction (conveyance direction), as shown in FIGS. 3 and 4, a guide 20 for guiding the paper delivered by the paper feed roller 15 and a separation member holder 21. In this separation member holding body 21, a separation member 22 generally called a separation pad is fixed and held by, for example, an adhesive. The guide 20 is fixed to the door 3.
[0012]
Here, if a direction orthogonal to the transport direction D of the paper P to be sent out is referred to as a paper width direction W, the guide 20 extends long in the paper width direction W, and a separating member holding body is provided at a substantially central portion thereof. A recessed housing portion 23 is formed so as to accommodate 21. As shown in FIG. 4, bearing portions 24 each formed of a notch portion having an open lower portion are formed on opposite wall portions of the guide 20 that partitions the accommodating portion 23, and the bearing portions 24 are separated into the bearing portions 24. A pair of pivot pins 25 projecting concentrically on the member holding body 21 are respectively fitted rotatably. As a result, the separating member holding body 21 is supported by the guide 20 so as to be rotatable around the rotation axis Y that is the central axis of the pivot pins 25. The rotation axis Y is located substantially parallel to the rotation axis X of the paper feed roller 15. As described above, the separation member holding body 21 is supported so as to be rotatable around a rotation axis Y substantially parallel to the rotation axis X of the paper feed roller 15.
[0013]
Further, a pressure member 27 made of, for example, a compression coil spring is disposed between the free end side of the separation member holding body 21 and the bottom wall 26 of the guide 20 that defines the bottom of the housing portion 23. The pressure member 27 presses the separation member holding body 21 toward the circumferential surface of the paper feed roller 15, and presses the separation member 22 attached to the separation member holding body 21 against the circumferential surface of the paper feed roller 15. Make use of.
[0014]
When a paper feed start signal is input, a clutch (not shown) is engaged, and the paper feed roller 15 starts to rotate in the direction of the arrow shown in FIG. Then, the uppermost paper P placed on the paper support plate 18 is sent out in the transport direction D. The paper feed roller 15 feeds the paper while rotating in contact with the paper P. In this way, the sheet is fed to the pressure contact portion between the sheet feeding roller 15 and the separating member 22 by the rotation of the sheet feeding roller 15. When a plurality of sheets are simultaneously fed at this time, a predetermined sheet to be sent out is sent. (The uppermost sheet in the illustrated example) and other sheets are separated, and only a predetermined sheet is fed to the transfer unit between the photoconductor 7 and the transfer device 11 shown in FIG. The toner image is transferred. In this way, the separation member 22 is configured so that the friction coefficient between the separation member 22 and the sheet is larger than the friction coefficient between the sheets so that the sheets can be separated one by one. When two sheets of paper enter the pressure contact portion with the member 22, the lower sheet receives a frictional force in the direction opposite to the conveyance direction of the sheet by the separation member 22. Since this frictional force is greater than the frictional force with which the upper sheet tries to carry the lower sheet, the upper and lower sheets are separated. The upper sheet separated into one sheet is conveyed while its lower surface slides on the separating member 22 having a high coefficient of friction, and the sheet is fed to the transfer unit.
[0015]
Since the paper feed roller 15 and the separating member 22 are worn over time and the image forming apparatus does not reach the end of its life, it is necessary to replace these parts with new ones when they reach the end of their lives. Therefore, the paper feed roller 15 is detachably attached to the door 3, and the separation member holding body 21 is also detachably attached to the guide 20. In order to remove the separating member holding body 21, first, the sheet feeding roller 15 is removed from the door 3, and then the separating member holding body 21 is rotated around the rotation axis Y in the counterclockwise direction in FIG. After making the holding body 21 stand substantially up and down, each pivot pin 25 of the separating member holding body 21 is extracted through the lower opening of each bearing portion 24 of the guide 20.
[0016]
Prior to removing the separation member holding body 21 from the guide 20, when the paper feed roller 15 is removed from the door 3 as described above, the separation member holding body 21 is held by the pressing force of the pressure member 27. There is a possibility that the body 21 may rotate suddenly so as to jump upward. Therefore, as shown in FIGS. 4 and 5, the guide 20 is formed with a pair of holes 28 that are spaced apart from each other in the paper width direction W, and the separating member holding body 21 is formed in each of the pair of holes 28. It has the leg part 29 to fit. When the paper feed roller 15 is removed as described above, the claw 30 formed at the lower part of each leg portion 29 engages with the edge of the hole 28, and the separating member holder 21 is moved upward by the action of the pressure member 27. Rotating to pop out is prevented. In this state, when the separating member holding body 21 is forcibly rotated in the counterclockwise direction in FIG. 2, each leg portion 29 is detached from each hole 28 while being elastically deformed.
[0017]
By the way, as described above, the separation member holding body 21 is rotatably supported by the guide 20, but in order to allow the separation member holding body 21 to freely rotate in this way, the separation member holding body 21 is provided. It is necessary to assemble the guide 20 with slight play (backlash). However, in this case, in the conventional sheet feeding device, when the sheet passes between the sheet feeding roller and the separating member, the separating member holder itself vibrates due to frictional vibration generated between the sheet and the separating member. However, this may cause abnormal noise.
[0018]
Therefore, in the paper feeding device of this example, as shown in FIGS. 2, 4 and 5, for example, a strip-shaped elastic film 31 made of a resin such as PET or a metal is interposed between the pair of holes 28 described above. It is fixed to the guide portion with, for example, an adhesive or a double-sided adhesive tape. As shown in FIG. 5, the elastic film 31 is inserted into each of the pair of holes 28 as shown in FIG. 5, and the end portions are in pressure contact with the leg portions 29 of the separating member holding body 21. The leg portions 29 are pressed toward the outer sides E in the paper width direction W. That is, the elastic film 31 pressurizes each leg portion 29 from the center CL (FIG. 3) in the width direction of the sheet in the outer direction E (FIG. 5) in the width direction W. As a result, although the separation member holding body 21 is assembled to the guide 20 with play, vibration of the separation member holding body when the sheet passes through the pressure contact portion between the paper feed roller 15 and the separation member 22 is suppressed. The occurrence of abnormal noise is effectively suppressed. In this way, the generation of abnormal noise can be prevented by a very simple configuration in which the elastic film 31 is provided.
[0019]
When the separation member holder 21 is assembled to the guide 20, if each leg 29 is inserted into each hole 28, each end of the elastic film 31 attached to the guide 20 is strongly pushed into each hole 28 by each leg 29. It is. In this way, each end of the elastic film 31 can be bent and inserted into each hole 28. The elastic film 31 is in pressure contact with the separating member holding body 21 so as to apply a force to the separating member holding body 21 in the paper width direction W, in other words, in the rotation axis Y direction of the separating member holding body 21. Therefore, the pressure member 27 does not affect the action of pressing the separation member holding body 21 in a direction substantially perpendicular to the rotational axis direction, and the separation member is always kept at a constant pressure. 22 can be pressed against the paper feed roller 15 to maintain a predetermined separation function of the paper. Further, as indicated by an arrow F in FIG. 5, even if the elastic film 31 applies a slight upward force to the leg portion 29 of the separation member holding body 21, a component force directed upward of this force. Since F1 is very small, it does not greatly affect the pressure with which the separation member 22 is pressed against the paper feed roller 15. In particular, when the thickness of the elastic film 31 is set to a small value of 0.1 to 0.25 mm, the force applied to the leg portion 29 by the elastic film 31 is reduced, and the upward component force F1 described above is extremely small. Thus, the influence of the separation member 22 on the pressure contacting the paper feed roller 15 can be neglected.
[0020]
In the illustrated example, as described above, the elastic film 31 is configured to pressurize the separating member holding body 21 toward each outward E in the paper width direction W orthogonal to the transport direction D of the fed paper. However, for example, the elastic film 31 is inserted only into the one hole 28, and the one leg portion 29 of the separation member holding body 21 is pressed by the elastic film 31. May be configured to pressurize only in one direction in the paper width direction W.
[0021]
Further, in the paper feeding device of this example, in order to prevent the separating member holding body 21 from coming out of the guide 20, an elastic film 31 is inserted into the holes 28 formed in the guide 20, and is similarly fitted into these holes 28. Since the leg portion 29 of the combined separation member holding body 21 is configured to be pressurized by the elastic film 31, it is not necessary to provide the separation member holding body 21 with a dedicated pressurized portion to be pressurized by the elastic film 31, The configuration can be simplified.
[0022]
Further, the elastic film 31 of this example is disposed below the separation member holding body 21, and when the separation member holding body 21 is removed from the guide 20 as described above, the elastic film 31 interferes with the separation member holding body 21. The elastic film 31 does not get in the way, and it is possible to prevent the maintainability of the sheet feeding device from being impaired.
[0023]
Each configuration described above can be applied to the other sheet feeding device 5 shown in FIG. FIG. 1 shows image forming means 6 for transferring an image to a sheet fed from a sheet feeding device and forming an image on the sheet. The present invention can also be widely applied to printers that directly form images on paper, copiers, facsimiles, image forming apparatuses composed of a multifunction machine having a plurality of functions thereof, and paper feeding apparatuses thereof.
[0024]
【The invention's effect】
According to the present invention, it is possible to suppress the vibration of the separation member holding body with a simple configuration and effectively suppress the generation of abnormal noise.
[Brief description of the drawings]
FIG. 1 is a schematic sectional view of an image forming apparatus.
FIG. 2 is a cross-sectional view of a paper feeding device.
FIG. 3 is a perspective view of a guide, a separating member holder, and a paper feed roller.
FIG. 4 is an exploded perspective view showing the separating member holding member in a state where it is removed from the guide.
5 is a cross-sectional view taken along line VV in FIG.
[Explanation of symbols]
4 Feeding device 6 Image forming means 15 Feeding roller 20 Guide 21 Separating member holder 22 Separating member 27 Pressure member 28 Hole 29 Leg 31 Elastic film D Transport direction E Outward P Paper W Paper width direction X Rotation axis Y Rotation axis

Claims (4)

  A paper feed roller that feeds the paper while rotating in contact with the paper, a separation member holder supported rotatably about a rotation axis substantially parallel to the rotation axis of the paper feed roller, and the separation member holding A separation member held by the body, and a pressure member that presses the separation member holding body toward the circumferential surface of the paper feed roller and presses the separation member against the circumferential surface of the paper feed roller. , By rotating the paper feed roller, the paper is sent to the pressure contact portion between the paper feed roller and the separating member, and when a plurality of papers are sent, the predetermined paper to be sent and the other paper are separated, In a paper feeding device that feeds only predetermined paper, an elastic film is provided that presses against the separation member holding body and applies a force to the separation member holding body in the direction of the rotation axis thereof. Paper feeder.   The sheet feeding device according to claim 1, wherein the elastic film pressurizes the separation member holding body toward each outer side in a sheet width direction orthogonal to a conveyance direction of a sheet to be fed.   The guide includes a guide for guiding the sheet fed by the sheet feeding roller, and the guide is formed with a pair of holes spaced apart in the sheet width direction, and the separation member holding body is the pair of holes. 3. The method according to claim 1, wherein the elastic film is inserted into each of the pair of holes to pressurize the legs toward each outer side in the paper width direction. Paper feeder.   4. An image forming apparatus comprising: the sheet feeding device according to claim 1; and an image forming unit that forms an image on a sheet fed from the sheet feeding device.

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