JP2004307118A - Sheet acting member, and sheet conveying device and image processing apparatus using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inexpensive and maintenance-free sheet acting member such as a conveying roller that prevents degradation of frictional force by paper powder adhesion and degradation of frictional force by abrasion, realizes a high durable roller member, and has long service life. <P>SOLUTION: The conveying roller contacts with a sheet and conveys the sheet with the frictional force. The conveying roller comprises a surface rubber section 22 having a plurality of micro projections 24 on an action surface with the sheet and an intermediate layer rubber section 23 disposed between the surface rubber section 22 and a support section. The hardness of the intermediate layer rubber section 23 is set lower than that of the surface rubber section 22. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a conveying roller that comes into contact with a sheet and conveys the sheet by the frictional force, or a sheet acting member such as a separation pad for separating the sheet, a sheet conveying apparatus using the same, an electrophotographic copying machine, a printer, The present invention relates to an image processing device such as a word processor and a facsimile device.
[0002]
[Prior art]
2. Description of the Related Art In recent years, image forming apparatuses, such as printers and copiers, that employ an electrophotographic method or other recording methods have become widespread. As the performance of the apparatus and the service life of the apparatus have been advanced, it has become necessary to improve the feeding accuracy and durability of the transport rollers used in the image forming apparatus. Separation pads used in image forming apparatuses also need to have improved separation accuracy and durability.
[0003]
Here, as shown in FIG. 9, a conventional conveying roller 100 includes a shaft 101 made of metal or a mold and a rubber material such as EPDM (ethylene / propylene rubber), CR rubber (chloroprene rubber), silicon rubber, urethane rubber, or the like. And a cylindrical rubber portion 102 that comes into contact with the recording sheet and conveys the recording sheet by frictional force. The cylindrical surface 102a of the cylindrical rubber portion 102 is arranged in the direction of arrow C or D shown in FIG. Polished.
[0004]
Further, the separation pad 103 shown in FIG. 10 is also made of a rubber material such as EPDM, CR rubber, silicon rubber, urethane rubber or the like, and has a rubber portion 104 which comes into contact with the transport roller, . The rubber surface 104a of the rubber portion 104 is polished in the direction of arrow E or F shown in FIG.
[0005]
[Problems to be solved by the invention]
However, the conventional transport roller and separation pad have the following problems.
[0006]
When the recording sheet is conveyed by the conventional conveyance roller, as the number of recording sheet conveyed increases, paper dust generated from the surface of the recording sheet adheres to the cylindrical surface of the conveyance roller, and the frictional force of the conveyance roller decreases. As a result, slippage occurs in the conveyance of the recording sheet, and there is a problem that an image defect or a jam occurs. Therefore, in order to prolong the product life of the apparatus main body, the user is requested to clean the transport roller, or the user can replace the transport roller. As a result, the usability has been reduced and the cost has been increased due to the addition of components due to the configuration in which the transport rollers can be replaced.
[0007]
Also, when a recording sheet is separated and conveyed using a conventional separation pad, as the number of recording sheets separated and conveyed increases, paper dust generated from the surface of the recording sheet adheres to the surface of the separation pad, and the frictional force of the separation pad increases. And the recording sheet is doubled, causing a problem of double feeding. Therefore, the same problem as in the case of the transport roller has occurred.
[0008]
The present invention is to solve the above-mentioned conventional problems, and an object of the present invention is to prevent a decrease in frictional force due to paper powder adhesion and a decrease in frictional force due to abrasion, realize a highly durable roller member and the like, achieve a long life and maintenance. An object of the present invention is to provide a free and inexpensive sheet operating member such as a conveying roller, a sheet conveying apparatus using the same, and an image forming apparatus.
[0009]
[Means for Solving the Problems]
A typical configuration according to the present invention for achieving the above object is a sheet working member for contacting a sheet, conveying the sheet by frictional force, or separating the sheet, and a plurality of working surfaces with the sheet. It has a surface layer having projections, and an intermediate layer provided between the surface layer and the support portion, wherein the hardness of the intermediate layer is lower than the hardness of the surface layer.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, an image forming apparatus that forms an image on a sheet will be described as an example of an image processing apparatus using a sheet acting member according to an embodiment of the present invention.
[0011]
[First Embodiment]
1st Embodiment demonstrates the example which used the sheet | seat action member as a conveyance roller with reference to FIGS. 1 is an enlarged explanatory view showing the nip state of the transport roller, FIG. 2 is an overall schematic explanatory view of the image forming apparatus, FIG. 3 is a perspective explanatory view showing the entire transport roller, and FIGS. FIG. 4 is an explanatory view of a minute projection formed on the roller surface.
[0012]
｛Image processing device｝
First, the overall configuration of the image forming apparatus will be described with reference to FIG. In FIG. 2, the image forming apparatus A separates and conveys the recording sheets P stacked by the sheet conveying apparatus B one by one, and the recording sheet P is image-formed by a conveying roller pair 1 including a conveying roller 1a and a conveying roller 1b. And image recording by an electrophotographic method. That is, the photosensitive drum 3 accommodated in the process cartridge 2 is rotated in synchronization with the conveyance of the recording sheet, and the surface of the photosensitive drum 3 is charged by the primary charger 4 and then selectively from the laser scanning optical system 5. An electrostatic latent image is formed by irradiating the latent image with an appropriate light, and the latent image is developed with toner by the developing device 6. Then, the toner image is transferred to the recording sheet P by applying a transfer bias to the transfer roller 7 to the transported recording sheet P.
[0013]
Next, the recording sheet P to which the toner image has been transferred is heated and pressed by the fixing device 8 to fix the toner image on the recording sheet P, and the fixed recording sheet P is discharged by a discharge roller pair including a discharge roller 9a and a discharge roller 9b. 9, the paper is discharged to the discharge tray 10.
[0014]
｛Sheet conveying device｝
The sheet conveying device B includes a feeding tray 11 that supports the recording sheet P, and a pressing plate 13 that is a pressing unit that presses the leading end side of the recording sheet P supported by the feeding tray 11 against the conveying roller 12. A pressure spring 14 for urging the pressure plate 13, a separation pad 15 for separating recording sheets P sent by the conveyance roller 12 one by one, and a separation pad 15 attached to the conveyance roller 12. And a separating spring 16 for biasing.
[0015]
The cam 17 is fixed to the shaft 18 of the transport roller 12, contacts the cam portion 13 a of the pressure plate 13, and in a device standby state, the recording material P is opposed to the pressure spring 14 so that the recording material P does not contact the transport roller 12. Is energizing.
[0016]
The transport roller 12 feeds the recording sheet P separated by the separation pad 15 to the transport path 19 while abutting on the uppermost sheet surface of the plurality of recording sheets P stacked and supported on the feed tray 11. To send.
[0017]
｛Seat action member｝
Next, the configuration of the transport roller 12 used in the sheet transport apparatus B will be described with reference to FIGS.
[0018]
The transport roller 12 is a sheet acting member that applies a transport force to the sheet by frictional force. As shown in FIG. 3, the shaft portion 20 as a support portion made of a metal or a mold and the outermost periphery of the transport roller 12 are provided. A cylindrical surface rubber portion 22 that is a surface layer and is formed of a rubber material such as EPDM, CR rubber, silicon rubber, or urethane rubber, contacts the recording sheet P, and conveys the recording sheet P by frictional force; An intermediate layer provided between the outer periphery of the shaft portion 20 and the surface rubber portion 22, the intermediate layer rubber portion 23 being made of a rubber material such as EPDM, CR rubber, silicon rubber, urethane rubber, or the like. Be composed.
[0019]
On the cylindrical surface 22a of the cylindrical surface rubber portion 22 of the transport roller 12, fine projections 24 are formed by fine processing, as shown in FIGS.
[0020]
(Micro projection)
As shown in FIG. 4, the minute projection 24 has a shape composed of an upright portion 24a rising from the cylindrical surface 22a and a spherical portion 24b at the tip of the upright portion 24a. The minute projections 24 are arranged so as to be at substantially equal intervals L with adjacent minute projections 24. The height of the minute protrusions 24 is formed in the range of 1 μm to 500 μm in consideration of the size and thickness of the recording sheet P to be conveyed.
[0021]
This is because if the thickness is less than 1 μm, the effect of preventing paper dust from adhering to the transport roller 12 is small, and the improvement in durability is small. Since the influence of the force on the transporting force increases and it becomes difficult to maintain a stable transporting force, it is desirable that the height of the minute projections 24 be in the above range.
[0022]
In the present embodiment, the upright portion 24a of the minute projection 24 has a cylindrical shape. Further, as shown in FIG. 5, the diameter R of the spherical portion 24b is larger than the cylindrical diameter (thickness) r of the upright portion 24a and smaller than the length h of the upright portion 24a.
[0023]
When the recording sheet P is transported by the transport roller 12 provided with the minute projections 24 in the above configuration, the transport roller 12 rotates in the direction of arrow A as shown in FIG. Conveyed in the direction. At this time, the recording sheet P is conveyed by a frictional force generated by contacting the spherical portion 24b of the conveying roller. As shown in FIG. 6A, the upright portion 24 a of the minute projection 24 which is being conveyed in contact with the recording sheet P is elastically deformed in a direction opposite to the conveying direction of the recording sheet P (the direction of arrow A). It has fallen. In this state, the recording sheet P is being conveyed, but during the conveyance of the recording sheet P, a minute falling object (hereinafter simply referred to as “paper dust”) from the surface of the recording sheet P at the contact portion between the recording sheet P and the spherical portion 24b. ) Occurs and increases near the contact portion.
[0024]
Then, when the conveyance of the recording sheet P is completed, the minute projections 24 are released from the elastically deformed state and return to the molding state, as shown in FIG. At this time, the paper dust S generated at the contact portion between the spherical portion 24b and the recording sheet P is deposited on the cylindrical surface 22a without adhering to the spherical portion 24b because the spherical portion 24b is minute.
[0025]
Here, when the recording sheet P is conveyed by the conveying roller 12, as the number of conveyed recording sheets P increases, the minute protrusions 24 of the conveying roller 12 that come into contact with the recording sheet P may be deformed or lost due to wear. Therefore, there is a possibility that the frictional force of the conveying roller 12 is reduced and the conveyance of the recording sheet is caused to slip.
[0026]
Therefore, if the hardness of the rubber material of the transport roller 12 is increased in order to increase the wear resistance of the minute projections 24, the wear resistance can be improved, but the nip width between the transport roller 12 and the separation pad 15 that is in contact is small. As a result, the number of contact surfaces with the recording sheet to be conveyed is reduced, and consequently, conveyance failure may occur.
[0027]
On the other hand, if the pressing force of the separation pad 15 is increased in order to increase the nip width between the conveyance roller 12 and the separation pad 15 that comes into contact, the torque load of the product increases.
[0028]
Thus, in the present embodiment, the above problem is improved by making the hardness of the roller different between the surface layer and the intermediate layer below the roller.
[0029]
(Hardness of elastic layer)
Next, the hardness of the transport roller 12 will be described. The intermediate layer rubber portion 23 of the transport roller 12 shown in FIGS. 1 and 3 is made of foamed sponge rubber (foamed layer) having holes or a low-hardness rubber material having a hardness of about 15 ° to 30 °, for example. For the surface rubber portion 22, a rubber material having a high hardness of, for example, 40 ° or more and excellent in wear resistance is used, and the hardness of the intermediate rubber portion 23 is set lower than the hardness of the surface rubber portion 22. .
[0030]
In FIG. 1, N is a nip between the transport roller 12 and the separation pad 15. In the transport roller 12 of the present embodiment, even when a rubber material having a high hardness and excellent wear resistance is used for the surface rubber portion 22, the surface hardness of the transport roller is reduced by setting the hardness of the intermediate rubber portion 23 low. Therefore, the width of the nip N between the transport roller 12 and the separation pad 15 can be increased while the pressing force of the separation pad 15 is low.
[0031]
As a result, not only the conveyance roller 12 having excellent wear resistance is realized, but also the feeding / conveying performance can be improved even when the pressing force of the separation pad 15 is low. There is also an effect that the driving torque of the motor can be reduced.
[0032]
The same effect can be naturally obtained even if the cross-sectional shape of the transport roller 12 is D-shaped. Further, in the present embodiment, the intermediate layer rubber portion 23 of the transport roller 12 is a single layer. However, even if a plurality of elastic layers are formed of a rubber material having a lower hardness than the surface layer rubber portion 22, the present embodiment is not limited to this. Has the same effect as
[0033]
[Second embodiment]
As a second embodiment of the present invention, an example in which a sheet action member is used for the separation pad 15 will be described with reference to FIGS. FIG. 7 is a schematic perspective explanatory view showing the entire separation pad, and FIG. 8 is an enlarged perspective explanatory view of a portion where minute projections provided on the separation pad are present.
[0034]
As shown in FIG. 7, the separation pad 15 according to the present embodiment is formed of a holder portion 25 as a support portion made of metal or a mold, and a rubber material made of EPDM, silicon rubber, urethane rubber, or the like. A high-friction surface rubber portion 26 that comes into contact with the recording sheet P and separates the recording sheet P by frictional force; and an intermediate layer provided between the holder portion 25 and the high-friction surface rubber portion 26. And an intermediate layer rubber portion 23 formed of a rubber material such as EPDM, CR rubber, silicon rubber, urethane rubber, or the like.
[0035]
The fine protrusions 24 similar to those of the first embodiment are provided on the high friction surface rubber portion 26 as the surface layer.
[0036]
Further, as in the first embodiment, the intermediate layer rubber portion 23 of the separation pad 15 is formed of a foamed sponge rubber having pores or a low-hardness rubber material having a hardness of about 15 ° to 30 °, for example. For the high friction surface rubber portion 26, a rubber material having a high hardness of, for example, a hardness of 40 ° or more and excellent wear resistance is used, and the hardness of the intermediate layer rubber portion 23 is set lower than the hardness of the high friction surface rubber portion 26. Have been.
[0037]
Therefore, even when a rubber material having high hardness and excellent wear resistance is used for the high friction surface rubber portion 26, the surface hardness of the separation pad can be reduced by setting the hardness of the intermediate rubber portion 23 low. When the sheet is separated by the separation pad 15, as shown in FIG. 5, the width of the nip N between the separation pad 15 and the transport roller 12 can be increased in a state where the pressing force of the separation pad 15 is low.
[0038]
As a result, the separation pad 15 having excellent wear resistance is realized, and the separation performance can be improved even when the pressing force of the separation pad 15 is low. There is also an effect that the torque can be reduced.
[0039]
[Other embodiments]
In the above-described embodiment, an example is shown in which the upright portion 22a of the minute projection 22 is formed in a cylindrical shape. However, the shape of the upstanding portion 22a is not limited to a cylindrical shape, and may be a conical shape, a polygonal shape, or a polygonal column shape.
[0040]
Further, in the first embodiment described above, the transport roller 12 has been described as a sheet acting member. However, the transport roller 12 has the same configuration for the other transport roller 1a, the transfer roller 7, and the discharge roller 9a. The same effect can be obtained.
[0041]
In the above-described embodiment, an image forming apparatus that conveys a sheet as an image processing apparatus and records an image on the sheet is exemplified. However, a conveyance roller or a separation pad as a sheet operation member described above, or a plurality of sheet conveyance apparatuses are used. It can also be suitably used in an image reading apparatus that separates and conveys the originals one by one and reads the originals by image reading means.
[0042]
【The invention's effect】
As described above, according to the present invention, it is possible to improve the abrasion resistance of the fine projections provided on the sheet acting member such as the transport roller and the separation pad, and at the same time, to reduce the nip width even when the pressing force on the sheet acting member is reduced. As a result, a highly durable sheet working member can be realized, and a long-life, low-torque sheet conveying device and the like can be realized.
[Brief description of the drawings]
FIG. 1 is an enlarged explanatory view showing a nip state of a transport roller.
FIG. 2 is an overall schematic diagram of the image forming apparatus.
FIG. 3 is an explanatory perspective view showing the entirety of a transport roller.
FIG. 4 is an explanatory view of a minute projection formed on a roller surface.
FIG. 5 is an explanatory diagram of a minute projection formed on a roller surface.
FIG. 6 is an explanatory diagram of a minute projection formed on a roller surface.
FIG. 7 is a schematic perspective explanatory view showing the entire separation pad.
FIG. 8 is an enlarged perspective explanatory view of a portion where a minute projection provided on a separation pad exists.
FIG. 9 is a schematic perspective view of a conventional transport roller.
FIG. 10 is a schematic perspective view of a conventional separation pad.
[Explanation of symbols]
A: Image forming apparatus B: Sheet conveying apparatus P: Recording sheet S: Paper dust 1: Conveying roller pair 1a: Conveying roller 1b: Conveying roller 2: Process cartridge 3: Photoconductor drum 4: Primary charging device 5: Laser scanning optical System 6 Developing device 7 Transfer roller 8 Fixing device 9 Discharge roller pair 9a Discharge roller 9b Discharge roller 10 Discharge tray 11 Feed tray 12 Transport roller 13 Pressure plate 13a Cam portion 14 Compression spring 15… Separation pad 16… Separation spring 17… Cam 18… Shaft 19… Convey path 20… Shaft portion 22… Surface layer rubber portion 22a… Cylinder surface 23… Intermediate layer rubber portion 24… Small projection 24a… Standing portion 24b… Spherical Part 25: Holder part 26: High friction surface layer rubber part

Claims (8)

In the sheet action member for contacting the sheet, conveying the sheet by frictional force, or separating the sheet,
A surface layer having a plurality of protrusions on a working surface with the sheet,
An intermediate layer provided between the surface layer and the support,
Has,
A sheet operating member wherein the hardness of the intermediate layer is lower than the hardness of the surface layer. The sheet acting member according to claim 1, wherein the intermediate layer is a foamed layer having pores. The sheet according to claim 1, wherein the intermediate layer has a plurality of elastic layers, and at least one of the plurality of elastic layers has a hardness lower than a hardness of the surface layer. Working member. The sheet operating member according to any one of claims 1 to 3, wherein the sheet operating member is a transport roller for rotating and transporting the sheet. The said sheet | seat action member is a separation pad for contacting the sheet conveyed and isolate | separating several sheets into one sheet, The Claim 1 characterized by the above-mentioned. Sheet working member. In a sheet conveying device for conveying a sheet,
A sheet conveying device, comprising: a rotatable conveying roller that comes into contact with a sheet and applies a conveying force to the sheet by frictional force, wherein the sheet action member according to claim 4 is used as the conveying roller. In a sheet conveying device that separates and conveys a plurality of sheets one by one,
A conveying member for applying a conveying force to the sheet;
A separation pad for contacting the conveyed sheet and separating a plurality of sheets into one;
Has,
A sheet conveying device using the sheet acting member according to claim 5 as the separation pad. The sheet according to claim 6, further comprising an image forming unit that forms an image on a sheet or an image reading unit that reads an image of a sheet document, and feeding a sheet to the image forming unit or the image reading unit. An image processing device comprising a transport device.

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