JP2003295721A - Foam roller, cleaning roller, process device and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a foam roller and a cleaning roller comprising the foam roller, which can reduce the productivity and the cost and can uniformly press the member to be pressed. And a process device provided with the cleaning roller, and an image forming device provided with the process device. A roller layer (54b) of a primary cleaning roller (54) has an outer peripheral surface (81) extending in the axial direction as a foam surface, and each roller end (82) has a skin surface at each end surface.
And Then, the outer peripheral portion 85 of the end of each roller end 82
To the radially outer end 82 with respect to the end inner peripheral 84 side.
a is curved in an arcuate cross-section so as to be directed inward in the axial direction, and the outer peripheral surface 81 and a surface (end surface) directed radially inward from a radially outer end portion 82 a of each end outer peripheral portion 85.
Is formed to be larger than 90 ° and smaller than 180 °.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a foam roller, a cleaning roller, a process device and an image forming apparatus.

[0002]

2. Description of the Related Art Conventionally, in a process device mounted on an electrophotographic image forming apparatus, toner remaining on the surface of a photosensitive drum after transfer of a toner image onto the paper or the surface of the photosensitive drum from the paper is removed. A cleaning roller is provided for removing the adhered paper powder and the like.

Such cleaning rollers are usually
A roller portion made of foam is coated around the metal roller shaft in the axial direction. For example, the roller shaft is arranged in a predetermined mold, and the resin is previously set in the mold. ,
It is manufactured by injecting a foam molding raw material in which a foaming agent, a conductive agent, and the like are kneaded, and foam molding to mold a roller portion made of foam.

In the production of such a cleaning roller, skin layers are formed on the portion where the foamed resin comes into contact with the inner surface of the mold during foam molding, that is, on the outer peripheral portion and both end portions of the roller portion. Therefore, after foam molding,
First, by cutting the skin layers on both ends of the roller portion, and then polishing and removing the skin layers on the outer peripheral portion,
Both end surfaces and the outer peripheral surface of the roller portion are processed to be foamed surfaces.

[0005]

However, if both end portions of the roller portion are cut and the outer peripheral portion is polished after foam molding, the number of processing steps becomes multiple, and the productivity is not improved and the cost is reduced. There is a problem that you can not do it.

However, the outer peripheral surface of the roller portion needs to be a foamed surface because it comes into contact with the surface of the photosensitive drum, while both end surfaces of the roller portion are not necessarily foamed surfaces. After forming, it is possible to reduce the number of steps by omitting the step of cutting both ends of the roller portion and performing only the polishing step of the outer peripheral portion of the roller portion.

However, if the skin layers are left on both ends of the roller portion, the rigidity of both end portions of the roller portion formed by the skin layer when the cleaning roller is pressed against the photosensitive drum is more axial than that of both end portions. Since the rigidity of the roller part formed only by the inner foam layer is greater, both ends of the roller part are in strong pressure contact with the photosensitive drum, and the roller parts axially inward of both ends are in weak contact with the photosensitive drum. As a result, it is impossible to make uniform pressure contact in the axial direction, and as a result, a uniform and necessary pressure contact force between the cleaning roller and the photosensitive drum may not be obtained.

The present invention has been made in view of the above circumstances, and an object thereof is to reduce productivity and cost, and to press the member to be pressure-contacted uniformly. It is an object of the present invention to provide a foam roller, a cleaning roller including the foam roller, a process device including the cleaning roller, and an image forming apparatus including the process device.

[0009]

To achieve the above object, the invention according to claim 1 comprises a shaft portion and a foam provided around the shaft portion in the axial direction of the shaft portion. In a foam roller including a roller portion, an outer peripheral surface along the axial direction of the roller portion is a foamed surface, and a skin layer is formed on each end portion in the axial direction of the roller portion, each end surface being a skin surface. Both ends of the roller portion in the axial direction are formed so that the reaction force from the pressed member is relaxed when the roller portion is pressed against the pressed member along the axial direction. Is characterized by.

According to this structure, since both axial end portions of the roller portion remain the skin layers, the step of cutting both axial end portions of the roller portion can be omitted at the time of manufacturing to improve productivity. Also, the cost can be reduced. Moreover, when the foam roller is brought into pressure contact with the member to be pressed, even if skin layers are formed at both ends in the axial direction of the roller unit, the reaction force from the member to be pressed is applied to both ends in the axial direction of the roller unit. Therefore, it is possible to avoid strong pressure contact with the pressed member at both axial end portions of the roller portion.

The invention according to claim 2 is a shaft part,
In a foam roller provided with a roller portion made of foam provided around the shaft portion along the axial direction of the shaft portion, an outer peripheral surface of the roller portion along the axial direction is a foam surface, and the roller portion Skin layers whose end surfaces are skin surfaces are formed at both axial end portions of the roller portion, and the axial end portions of the roller portion are the outer peripheral surface along the axial direction of the roller portion and the roller portion. It is characterized in that the angle formed with the end face in the axial direction is greater than 90 ° and less than 180 °.

According to this structure, since both axial end portions of the roller portion remain the skin layers, the step of cutting both axial end portions of the roller portion can be omitted at the time of manufacturing to improve productivity. Also, the cost can be reduced. In addition, the angle between the outer peripheral surface of the roller portion along the axial direction and the axial end surface of the roller portion is greater than 90 ° and 1
Since it is formed to be less than 80 °, when the foam roller is brought into pressure contact with the pressed member, the axial end surface of the roller portion falls inward in the axial direction, so that the reaction force from the pressed member is relaxed. be able to. Therefore, the reaction force from the pressure-contacted member is satisfactorily relaxed by a simple configuration that merely defines the angle of the end surface with respect to the outer peripheral surface,
It is possible to avoid strong pressure contact with the pressed member at both axial end portions of the roller portion.

The invention according to claim 3 is a shaft part,
In a foam roller provided with a roller portion made of foam provided around the shaft portion along the axial direction of the shaft portion, an outer peripheral surface of the roller portion along the axial direction is a foam surface, and the roller portion Skin layers whose end faces are skin surfaces are formed at both axial end portions of the roller portion, the roller portion has a radial thickness of 3 mm or more, and the skin layer has a thickness of 1 mm or less. It is characterized by that.

According to this structure, since both axial end portions of the roller portion remain the skin layers, the step of cutting both axial end portions of the roller portion can be omitted at the time of manufacturing to improve productivity. Also, the cost can be reduced. Moreover, since the thickness of the skin layer is smaller than the thickness of the roller portion made of foam in the radial direction, when the foam roller is brought into pressure contact with the pressure-contact member, both axial end portions of the roller portion are It is possible to bend the reaction force from the pressure-contacted member by bending to the same extent as the roller portions axially inward of both end portions. Therefore, the reaction force from the pressure-contacted member can be satisfactorily relaxed and strong pressure-contact with the pressure-contacted member at both ends in the axial direction of the roller portion can be avoided by a simple method that only selects molding conditions.

The invention described in claim 4 is the same as that of claim 1.
The invention according to any one of items 1 to 3 is characterized in that stress relieving portions for relieving the reaction force are formed on both axial end faces of the roller portion.

According to this structure, stress relieving portions for relieving the reaction force are formed on both end surfaces of the roller portion in the axial direction. Therefore, when the foam roller is pressed against the pressed member, In the stress relaxing portion, the reaction force from the pressed member can be relaxed. Therefore, the reaction force from the pressure-contacted member can be satisfactorily relaxed and a strong pressure-contact with the pressure-contacted member at both axial ends of the roller portion can be avoided by a simple configuration in which only the stress relaxation portion is provided. it can.

The invention described in claim 5 is the same as in claim 4
In the invention described in (1), the stress relaxation portion is an annular recess formed on both axial end surfaces of the roller portion and recessed inward in the axial direction.

According to such a construction, only the annular recesses which are recessed inward in the axial direction are formed on both end surfaces of the roller portion in the axial direction, and when the foam roller is brought into pressure contact with the pressed member, The concave portion can reduce the reaction force from the pressed member. Therefore, the reaction force from the pressed member can be satisfactorily relaxed while easily forming the stress relieving portion by the recess.

The invention according to claim 6 is the same as claim 4
In the invention described in (1), the stress relaxation portion is an annular protrusion formed on both axial end surfaces of the roller portion and protruding outward in the axial direction.

According to this structure, only the annular protrusions projecting outward in the axial direction are formed on both end surfaces of the roller portion in the axial direction. A reaction force from the pressed member can be reduced by the protrusion. Therefore, it is possible to satisfactorily reduce the reaction force from the pressed member while easily forming the stress relaxation portion by the protrusion.

The invention described in claim 7 is the same as claim 1.
In the invention described in any one of (1) to (6), the shaft portion is arranged in a predetermined mold, and a foam molding raw material is injected into the mold to perform foam molding, and then along the axial direction of the roller portion. It is characterized in that it is obtained by processing only the outer peripheral portion.

According to this structure, since the roller portion is foam-molded in the mold, it is possible to form substantially spherical uniform cells. Therefore, the foam roller
In the axial direction, it is possible to press the member to be pressed with a uniform pressing force. Further, since only the outer peripheral portion is processed and the end portion is not processed, it is possible to improve productivity and reduce cost by reducing man-hours.

The invention described in claim 8 is the invention according to claim 7.
In the invention described in above, after the foam molding, the skin layer formed on the outer peripheral portion of the roller portion along the axial direction is removed to expose the foamed surface as the outer peripheral surface of the roller portion along the axial direction. I am trying.

According to this structure, after foam molding,
By removing the skin layer formed on the outer peripheral portion of the roller portion along the axial direction to expose the foamed surface as the outer peripheral surface of the roller portion along the axial direction, the outer peripheral surface can be easily and reliably formed into the foamed surface. it can.

According to a ninth aspect of the present invention, there is provided a cleaning roller provided in an image forming apparatus, comprising the foam roller according to any one of the first to eighth aspects.

According to this structure, the cleaning roller can be brought into uniform pressure contact with the pressure-contact member, so that good cleaning can be achieved.

According to a tenth aspect of the present invention, in a process apparatus having an image carrier, a cleaning roller for cleaning the surface of the image carrier is provided.
The cleaning roller comprises the foam roller according to any one of claims 1 to 8.

According to this structure, the cleaning roller can be brought into uniform pressure contact with the image carrier.
The surface of the image carrier can be cleaned well. Therefore, good development and transfer can be achieved.

An eleventh aspect of the present invention is an image forming apparatus including the process apparatus according to the tenth aspect.

With such a process device,
Since good development and transfer can be achieved, good image formation can be achieved.

[0031]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a side sectional view of an essential part showing an embodiment of a laser printer as an image forming apparatus of the present invention.

In FIG. 1, the laser printer 1 is
An electrophotographic laser printer that forms an image by a non-magnetic single-component developing method, including a feeder unit 4 for feeding a sheet 3 into a main body casing 2 and a predetermined sheet 3 for the fed sheet 3. The image forming unit 5 for forming an image is provided.

The feeder portion 4 is detachably mounted on the bottom of the main body casing 2, a paper feeding mechanism portion 7 provided at one end of the paper feeding tray 6, and a paper feeding mechanism. Conveying rollers 8 and 9 are provided downstream of the section 7 in the conveying direction of the sheet 3, and registration rollers 10 are provided downstream of the conveying rollers 8 and 9 in the conveying direction of the sheet 3.

The paper feed tray 6 has a box shape with an open upper surface for accommodating the sheets 3 in a laminated form, and is attachable to and detachable from the bottom of the main body casing 2 in the horizontal direction. A paper pressing plate 11 is provided in the paper feed tray 6. The sheet pressing plate 11 is capable of stacking the sheets 3 in a stacked manner, and is swingably supported at the end portion far from the sheet feeding mechanism section 7, whereby the sheet feeding mechanism section 7 is supported.
The end portion closer to is movable up and down, and is biased upward from the back side by a spring (not shown). Therefore, as the stacking amount of the sheets 3 increases, the sheet pressing plate 11 swings downward against the biasing force of the spring with the end portion farther from the sheet feeding mechanism section 7 as a fulcrum.

The paper feed mechanism section 7 is provided with a paper feed roller 12, a separation pad 13 facing the paper feed roller 12, and a spring 14 arranged on the back side of the separation pad 13, and the spring 14 The separation pad 13 is pressed against the paper feed roller 12 by the urging force.

Then, the uppermost sheet 3 on the sheet pressing plate 11 is pressed from the back side of the sheet pressing plate 11 toward the sheet feeding roller 12 by a spring (not shown), and is fed by the rotation of the sheet feeding roller 12. Roller 12 and separation pad 1
After being sandwiched by 3 and 3, the sheets are separated and fed one by one by their cooperation. The fed paper 3 is conveyed by the conveyance roller 8
And 9 to the registration roller 10.

The registration roller 10 is composed of a pair of rollers, and after the sheet 3 is subjected to a predetermined registration, it is sent to an image forming position (a contact portion between a photosensitive drum 28 and a transfer roller 31 described later). .

Further, the feeder section 4 of the laser printer 1 further feeds the multi-purpose tray 15 on which sheets 3 of arbitrary size are stacked and the sheets 3 stacked on the multi-purpose tray 15. The multi-purpose sheet feeding mechanism section 16 and the multi-purpose conveying roller 17 are provided.

The multi-purpose tray 15 is constructed so that sheets 3 of any size can be stacked in a stack.

The multi-purpose paper feeding mechanism section 16 includes a multi-purpose paper feeding roller 18, a multi-purpose separating pad 19 facing the multi-purpose paper feeding roller 18,
And a spring 20 arranged on the back side of the multi-purpose separating pad 19, and by the urging force of the spring 20,
The multi-purpose separation pad 19 is pressed against the multi-purpose paper feed roller 18.

Then, the uppermost sheet 3 stacked on the multi-purpose tray 15 is sandwiched between the multi-purpose sheet feeding roller 18 and the multi-purpose separating pad 19 by the rotation of the multi-purpose sheet feeding roller 18, and then the sheets are stacked. By the cooperation of, the sheets are separated and fed one by one. The fed paper 3 is sent to the registration rollers 10 by the multi-purpose carrying roller 17.

The image forming section 5 includes a scanner section 21, a process unit 22 as a process device, a fixing section 23 and the like.

The scanner section 21 is provided in the upper part of the main body casing 2, and has a laser emitting section (not shown), a polygon mirror 24 that is driven to rotate, and lenses 25a and 25.
b, a reflecting mirror 26 and the like, and a polygon mirror 23, a lens 25a, a laser beam based on predetermined image data emitted from the laser emitting section, as shown by a chain line,
The reflecting mirror 26 and the lens 25b are passed or reflected in this order, and the surface of the photosensitive drum 28 of the process unit 22, which will be described later, is irradiated by high-speed scanning.

The process unit 22 includes the scanner unit 21.
It is disposed below and is detachably attached to the main body casing 2. This process unit 22 is shown in FIG.
As shown in FIG. 3, in the drum frame 27 of the process unit 22, the photosensitive drum 28 as an image bearing member (pressed member), the developing cartridge 29, the scorotron charger 30, the transfer roller 31, and the cleaning unit 5 are provided.
3 and 3.

The developing cartridge 29 is detachably mounted on the drum frame 27, and the toner hopper 32, and the supply roller 33, the developing roller 34 and the layer thickness regulating blade 3 provided on the side of the toner hopper 32.
5 and.

The toner hopper 32 is filled with a positively charging non-magnetic one-component toner as a developer. As this toner, styrene-based monomers such as styrene,
A polymerizable monomer represented by acrylic monomers such as acrylic acid, alkyl (C1 to C4) acrylate, and alkyl (C1 to C4) methacrylate is copolymerized by a known polymerization method such as suspension polymerization. The polymerized toner obtained by this is used. The polymerized toner has a substantially spherical shape with an average particle size of about 6 to 10 μm and has very good fluidity. The polymerized toner is mixed with a coloring agent such as carbon black or wax. Further, an external additive such as silica is added to improve the fluidity of the toner.

Further, the toner hopper 32 is provided with an agitator 36. The agitator 36 includes a rotating shaft 37 rotatably supported in the center of the toner hopper 32.
And a stirring blade 38 provided around the rotating shaft 37
And the film 3 attached to the free end of the stirring blade 38.
9 and 9. When the rotary shaft 37 rotates in the direction of the arrow, the stirring blade 38 moves in the circumferential direction, the film 39 scrapes up the toner in the toner hopper 32, and conveys it toward the supply roller 33 described below.

A cleaner 4 for cleaning the remaining toner amount detection window 40 provided on the side wall of the toner hopper 32 is provided on the side of the rotary shaft 37 opposite to the side where the stirring blade 38 is provided.
1 is provided.

The supply roller 33 is provided on the side of the toner hopper 32 so as to be rotatable in the direction opposite to the rotation direction of the agitator 36. The supply roller 33 is configured by coating a metal roller shaft with a conductive urethane sponge.

The developing roller 34 is provided on the side of the supply roller 33 so as to be rotatable in the same direction as the rotation direction of the supply roller 33. In the developing roller 34, the surface of a metal roller shaft is coated with a conductive elastic material, conductive urethane rubber or silicone rubber containing carbon fine particles, and the surface of the elastic material contains urethane containing fluorine. It is formed by coating a coating layer of rubber or silicone rubber. A power source (not shown) is connected to the roller shaft of the developing roller 34, and a predetermined developing bias is applied.

The supply roller 33 and the developing roller 34 are arranged so as to face each other and are in contact with the developing roller 34 in such a state that the supply roller 33 is compressed to some extent. Is
At their facing contact portions, they rotate in opposite directions.

The layer thickness regulating blade 35 is composed of the supply roller 33.
Between the supply roller 33 and the photosensitive drum 28 in the rotation direction of the developing roller 34, and is arranged to face the developing roller 34 along the axial direction of the developing roller 34. There is. The layer thickness regulating blade 35 includes a leaf spring member 42, a pressure contact portion 43 provided at the tip of the leaf spring member 42 and made of insulating silicone rubber that comes into contact with the developing roller 34, and the leaf spring member 4.
A back-up member 44 provided on the back surface of No. 2 and a support member 45 for supporting the rear end portion of the leaf spring member 42 on the developing cartridge 29 are provided.

The layer thickness regulating blade 35 is composed of the leaf spring member 42.
Is supported by the developing cartridge 29 by the support member 45, the pressing portion 43 is pressed against the surface of the developing roller 34 by the elastic force of the leaf spring member 42.

The toner in the toner hopper 32 is scraped up by the rotation of the agitator 36 and conveyed toward the supply roller 33. By the rotation of the agitator 36, the cleaner 41 is rotated and the window 40 is cleaned.

The toner conveyed to the supply roller 33 is rotated by the rotation of the supply roller 33, and the developing roller 3
4 is supplied. From the supply roller 33 to the developing roller 3
At the time of supplying the toner to the No. 4, the toner is rubbed between the supply roller 33 and the developing roller 34, and is positively charged.

The charged toner is carried on the surface of the developing roller 34, and as the developing roller 34 rotates, the pressure contact portion 4 between the developing roller 34 and the layer thickness regulating blade 35.
Enter between 3 and. When the toner passes between the developing roller 34 and the pressure contact portion 43, the toner is further charged by friction, the thickness of the layer is regulated, and the toner is carried on the surface of the developing roller 34 as a thin layer.

The photosensitive drum 28 is disposed on the side of the developing roller 34 so as to face the developing roller 34, and is supported by the drum frame 27 so as to be rotatable in the direction opposite to the rotating direction of the developing roller 34. This photosensitive drum 2
Reference numeral 8 denotes a cylindrical aluminum surface on which a positively chargeable photosensitive layer made of polycarbonate or the like is formed, and the cylindrical aluminum is electrically grounded.

The scorotron charger 30 is disposed above the photosensitive drum 28 so as not to come into contact with the photosensitive drum 28 with a predetermined gap therebetween, and is supported by the drum frame 27. This scorotron charger 30
Is a scorotron-type charger for positive charging that generates corona discharge from a charging wire made of tungsten, and uniformly charges the surface of the photosensitive drum 28 to a positive polarity. A grid electrode 30a is provided between the wire and the photosensitive drum 28.

The cleaning unit 53 is the drum frame 2
7 inside the developing roller 34 with respect to the photosensitive drum 27.
Which is provided on the opposite side of the primary cleaning roller 54 and the secondary cleaning roller 5 as a foam roller.
5, a paper dust storage portion 56 and a scraper 57 are provided.

The primary cleaning roller 54 is on the downstream side of the position facing the transfer roller 31, which will be described later, in the rotation direction of the photosensitive drum 28, and is the scorotron charger 3.
On the upstream side of the position facing 0, it is arranged so as to be in contact with the photosensitive drum 28. As shown in FIG. 3, the primary cleaning roller 54 includes a roller shaft 54a composed of a shaft body obtained by depositing nickel plating on an iron material manufactured by a drawing method, and conductive silicone rubber, foam urethane rubber, foam EPDM, or the like. And a roller portion 54b made of a flexible foam. The roller portion 54b is formed so that both end portions in the axial direction of the roller shaft 54a are exposed.
It is provided around the roller shaft 54a in the axial direction of a. The primary cleaning roller 54 is connected to the photosensitive drum 28 via a gear (not shown), and is rotatably driven in the arrow direction (clockwise direction) by the drum frame 27 as the photosensitive drum 28 is driven to rotate. It is supported.

The secondary cleaning roller 55 has a
It is arranged on the opposite side of the photosensitive drum 28 to the next cleaning roller 54 so as to come into contact with the primary cleaning roller 54. The secondary cleaning roller 55 is composed of a shaft body in which nickel plating is deposited on an iron material manufactured by a drawing method, and the roller shaft 5 at both ends thereof.
5a and a roller portion 5 having a diameter larger than that of the inner roller shaft 55a.
5b is integrally formed. Also, the roller portion 55b
Rz (10-point average surface roughness) is 3.2μ.
It is set to m or less. The secondary cleaning roller 55 is connected to the primary cleaning roller 54 via a gear (not shown), and the primary cleaning roller 5
Along with the rotation drive of No. 4, the primary cleaning roller 54
The drum frame 27 can be rotated in the same direction as
Supported by.

The paper dust storage portion 56 is formed as a space defined by the drum frame 27 on the side opposite to the primary cleaning roller 54 with respect to the secondary cleaning roller 55.

The scraper 57 is supported by the drum frame 27 above the secondary cleaning roller 55 so as to come into contact with the secondary cleaning roller 55.
The scraper 57 is made of a foam such as urethane and is configured to scrape the paper dust attached to the secondary cleaning roller 55.

As the photosensitive drum 28 rotates, the surface of the photosensitive drum 28 is uniformly positively charged by the scorotron charger 30, and the laser beam emitted from the scanner section 21 is generated based on predetermined image data. It is exposed by being irradiated and an electrostatic latent image is formed.

Next, when the developing roller 34 rotates, the toner carried on the surface of the developing roller 34 and positively charged toner is brought into contact with the photosensitive drum 28 so as to face the surface of the photosensitive drum 28. The electrostatic latent image to be formed, that is, the surface of the photosensitive drum 28 that is uniformly positively charged, is supplied to the exposed portion exposed by the laser beam and whose potential is lowered, and is selectively carried. Visualized.

The transfer roller 31 is disposed below the photosensitive drum 28 so as to face the photosensitive drum 28, and is supported by the drum frame 27 so as to be rotatable in the direction opposite to the rotational direction of the photosensitive drum 28. The transfer roller 31 is formed by coating a metal roller shaft with a conductive rubber material, and a power source (not shown) is connected to the roller shaft. When the toner is transferred to the paper 3, a predetermined transfer bias is applied.

Then, as the photosensitive drum 28 rotates, the paper 3 conveyed from the registration roller 10 contacts the surface of the photosensitive drum 28 while the photosensitive drum 28 passes between the photosensitive drum 28 and the transfer roller 31. The toner carried on the surface of the drum 28 is transferred to the paper 3. The sheet 3 to which the toner has been transferred is conveyed toward the fixing unit 23 via the conveyance belt 46, as shown in FIG.

The fixing section 23 is provided on the side of the process unit 22 and on the downstream side in the conveying direction of the sheet 3, and is provided with a heating roller 47, a pressing roller 48, and a conveying roller 49. The heating roller 47 is provided with a halogen lamp as a heater in a metal tube. The pressing roller 48 is disposed below the heating roller 47 so as to face the heating roller 47, and is provided so as to press the heating roller 47 from below. Further, the transport roller 49 is provided on the downstream side of the heating roller 47 and the pressing roller 48 in the transport direction of the sheet 3.

The toner transferred to the sheet 3 is melted by heat and fixed to the sheet 3 while passing between the heating roller 47 and the pressing roller 48. The paper 3 is conveyed by the conveyance roller 49 to the conveyance roller 50 provided in the main body casing 2.
Also, the sheet is conveyed toward the sheet discharge roller 51.

The carrying roller 50 is provided on the downstream side of the carrying roller 49 in the carrying direction of the paper 3, and the paper discharging roller 5 is provided.
1 is provided above the discharge tray 52. The sheet 3 conveyed by the conveying roller 49 is conveyed by the conveying roller 50.
The sheet is conveyed to the sheet discharge roller 51 by the sheet discharge roller 51, and then discharged onto the sheet discharge tray 52 by the sheet discharge roller 51.

In this laser printer 1, the photosensitive drum 2 is transferred after being transferred onto the sheet 3 by the transfer roller 31.
The residual toner remaining on the surface of No. 8 is collected by the developing roller 34, that is, the so-called cleanerless developing method. If the residual toner is collected by such a cleanerless developing method, the photosensitive drum 2
No special member such as a blade for removing the residual toner from No. 8 and a waste toner storage section are not required, and the apparatus configuration can be simplified.

In the laser printer 1, the cleaning unit 53 temporarily captures the residual toner remaining on the surface of the photosensitive drum 28 after the transfer, and at the same time, the paper attached from the paper 3 to the surface of the photosensitive drum 28 at the time of transfer. I try to collect the powder.

That is, when the toner is transferred to the sheet 3, a bias (negative bias) lower than the surface potential of the photosensitive drum 28 is applied in order to attract the toner on the photosensitive drum 28 to the primary cleaning roller 54. It is applied to the primary cleaning roller 54. Then, the toner remaining on the photosensitive drum 28 is removed by the primary cleaning roller 54.
To be temporarily captured by.

On the other hand, when the toner is not transferred to the paper 3,
That is, in order to attract the paper dust on the photosensitive drum 28 to the primary cleaning roller 54 during a period corresponding to the interval between the continuously fed sheets 3 and the sheet 3, a bias higher than the surface potential of the photosensitive drum 28 is applied. (Positive bias) is applied to the primary cleaning roller 54. Then, the toner temporarily captured by the primary cleaning roller 54 is returned to the photosensitive drum 28, and the paper dust adhered to the photosensitive drum 28 from the paper 3 at the time of transfer is removed by the primary cleaning roller 5.
4 is captured. The toner returned to the photosensitive drum 28 is
It is collected by the developing roller 34.

Therefore, even if a large amount of residual toner remains on the surface of the photosensitive drum 28 after the transfer, the residual toner can be reliably collected by the developing roller 34. Therefore, it is possible to prevent the adverse effect on the image quality due to the toner remaining on the photosensitive drum 28.

Since only the paper dust on the primary cleaning roller 54 is attracted to the secondary cleaning roller 55, the secondary cleaning roller 55 has a bias (positive polarity) higher than the surface potential of the primary cleaning roller 54. Bias) is always applied.

When the paper dust captured by the primary cleaning roller 54 faces the secondary cleaning roller 55,
It is always electrically captured by the secondary cleaning roller 55. The paper dust captured by the secondary cleaning roller 55 is
When facing the scraper 57, it is scraped off by the scraper 57 and stored in the paper dust storage section 56.

That is, in the cleaning section 53,
By the primary cleaning roller 54, the photosensitive drum 28
The remaining toner and paper dust on the top are electrically sucked. The toner attracted by the primary cleaning roller 54 is electrically returned onto the photosensitive drum 28, while the paper dust attracted by the primary cleaning roller 54 is discharged by the secondary cleaning roller 5.
It is electrically sucked by 5 and captured by the secondary cleaning roller 55. Therefore, the paper dust can be efficiently removed in parallel with the recovery of the residual toner by the cleanerless developing method, and the paper dust removing performance can be improved.

Moreover, since the paper dust captured by the secondary cleaning roller 55 is scraped off by the scraper 57 and stored in the paper dust storage section 56, the removed paper dust can be collected without scattering. be able to. Therefore, the paper dust that has been once removed will not
8 can be prevented from adhering, and the paper dust removing performance can be improved. Further, since the paper dust sucked by the secondary cleaning roller 55 by the scraper 57 is scraped off, the paper dust capturing performance of the secondary cleaning roller 55 can be maintained for a long period of time, and the paper dust removing performance can be maintained. .

As a result, it is possible to efficiently remove the paper dust while satisfactorily collecting the residual toner by the cleanerless developing method.

Further, the laser printer 1 is provided with a paper 3
Re-conveying unit 61 for forming an image on both sides of. The re-conveying unit 61 includes a reversing mechanism section 62.
And the re-conveyance tray 63 are integrally formed, and the re-conveyance tray 63 is inserted above the paper feed tray 6 while the reversing mechanism portion 62 is externally attached to the rear side of the main body casing 2. In such a state, it is detachably attached.

The reversing mechanism portion 62 is externally attached to the rear wall of the main body casing 2, a casing 64 having a substantially rectangular cross section is provided with a reversing roller 66 and a re-conveying roller 67, and a reversing guide plate 68 is provided from the upper end portion. It is projected upward.

On the downstream side of the conveying roller 49, the sheet 3 having an image formed on one surface and conveyed by the conveying roller 49 is reversed with respect to the direction toward the conveying roller 50 (solid line state). A flapper 65 for selectively switching to the direction toward the roller 66 (state of virtual line)
Is provided.

The flapper 65 is rotatably supported at the rear portion of the main body casing 2, and the transport roller 4
The sheet 3 arranged near the downstream side of 9 and having the image formed on one surface thereof by the excitation or non-excitation of a solenoid (not shown) and conveyed by the conveying roller 49 is directed to the conveying roller 50 (solid line state). And a direction toward the reversing roller 66 (state of an imaginary line), which will be described later, so as to be selectively swingable.

The reversing roller 66 is arranged on the downstream side of the flapper 65 and above the casing 64, and is composed of a pair of rollers, and is configured so that the rotation can be switched in the forward and reverse directions. The reversing roller 66 is
First, the sheet 3 is rotated in the forward direction so that the sheet 3 is reversed to the guide plate 6
8 and then rotate in the opposite direction to feed paper 3
Can be conveyed in the reverse direction.

The re-conveying roller 67 is on the downstream side of the reversing roller 66, and is the reversing roller 66 in the casing 64.
The sheet 3 which is disposed immediately below the reversing roller 66 is composed of a pair of rollers and is reversed by the reversing roller 66.
It is configured so that it can be transported to the No. 3 station.

The reversing guide plate 68 is a plate-like member that extends further upward from the upper end of the casing 64, and the paper 3 fed by the reversing roller 66.
Is configured to guide.

When images are to be formed on both sides of the sheet 3, the flapper 65 first causes the sheet 3 to reverse the roller 6.
6 and the reversing mechanism 62
Then, the sheet 3 having the image formed on one surface is received. After that, the received sheet 3 is turned over by the reverse roller 6
When the sheet 3 is sent to the sheet 6, the reversing roller 66 makes a positive rotation while sandwiching the sheet 3, and once conveys the sheet 3 along the reversing guide plate 68 toward the upper outside. Paper 3
Is sent to the upper outside, and when the vicinity of the rear end of the sheet 3 is nipped by the reversing roller 66, the normal rotation of the reversing roller 66 stops.

Next, the reversing roller 66 rotates in the reverse direction, and the sheet 3 is conveyed to the re-conveying roller 67 in a state in which the sheet 3 is reversed in the front-rear direction so as to face substantially right below. The timing for rotating the reversing roller 66 from the normal rotation to the reverse rotation is set to the fixing unit 2
The paper passage sensor 76 provided on the downstream side of the paper 3
It is controlled so that a predetermined time elapses from the time when the rear end is detected. Further, when the conveyance of the sheet 3 to the reversing roller 66 is completed, the flapper 65 is switched to the original state, that is, the state in which the sheet 3 sent from the conveying roller 49 is sent to the conveying roller 50.

Then, the sheet 3 conveyed to the re-conveyance roller 67 is conveyed to the re-conveyance tray 63 described below.

The re-conveyance tray 63 includes a paper supply section 69 to which the paper 3 is supplied, a tray body 70 and a skew roller 71.
Is equipped with.

The sheet supply section 69 is externally attached to the rear portion of the main body casing 2 below the reversing mechanism section 62, and is provided with a curved sheet guide member 72. Re-conveying roller 67
The sheet 3 fed from the sheet in a substantially vertical direction is guided in a substantially horizontal direction by the curved shape of the sheet guide member 72, and is delivered to the tray body 70 in a substantially horizontal state.

The tray main body 70 has a substantially rectangular plate shape and is provided above the paper feed tray 6 in a substantially horizontal direction. The upstream end of the tray main body 70 is connected to the paper guide member 72, and The downstream end is connected to the upstream end of the re-conveyance path 73 for guiding the sheet 3 from the tray body 70 to the conveyance roller 9. The downstream end of the re-conveyance path 73 extends toward the conveyance roller 9.

Further, in the conveyance path of the sheet 3 in the tray main body 70, skew rollers 71 for conveying the sheet 3 while abutting against a reference plate (not shown) are provided at predetermined intervals in the sheet 3 conveying direction. Two are arranged apart from each other.

Each of the skew rollers 71 is disposed in the vicinity of a reference plate (not shown) provided at one end of the tray body 70 in the width direction, and the skew line is arranged such that its axis is substantially orthogonal to the transport direction of the sheet 3. The drive roller 74 and the skew drive roller 74 are opposed to each other with the paper 3 interposed therebetween, and the axis of the drive roller 74 is inclined from the direction substantially orthogonal to the transport direction of the paper 3 toward the reference plane. And a slanted driven roller 75 arranged in the direction.

The sheet 3 sent out from the sheet supply unit 69 to the tray main body 70 is passed through the re-conveyance path 73 while the one end edge in the width direction of the sheet 3 is brought into contact with the reference plate by the skew roller 71. It is sent to the transport roller 9. The sheet 3 with the front and back reversed is conveyed toward the image forming position via the registration rollers 10. Then, again, the back surface of the sheet 3 conveyed to the image forming position is brought into contact with the photosensitive drum 28 to face it, and after the toner forming the visible image is transferred,
The image is fixed on the fixing unit 23 and discharged onto the discharge tray 52 in a state where images are formed on both sides.

Then, in this laser printer 1,
As shown in FIG. 3, the primary cleaning roller 54 has an outer peripheral surface 81 along the axial direction of the roller shaft 54a in the roller portion 54b (excluding a radially outer end portion 82a of each roller end portion 82 which will be described later. The same applies hereinafter). Are formed as exposed foamed surfaces of the cells. A skin layer 83 is formed on each roller end portion 82 at both axial ends of the roller portion 54b, and each end surface thereof is a skin surface where the cells are not exposed.

As shown in FIG. 4, each roller end 82 has a radially outer end that is axially flush with the outer peripheral surface 81 from the radially inner end 82b that contacts the outer peripheral surface of the roller shaft 54a. Up to the portion 82a, an end inner peripheral portion 84 is continuously formed radially inwardly and an end outer peripheral portion 85 is continuously formed radially outwardly.

The inner peripheral portion 84 of the end portion is formed in a flat shape along a direction orthogonal to the axial direction of the roller shaft 54a. Further, the end outer peripheral portion 85 is formed so that the outer end 82a in the radial direction is curved toward the inner side in the axial direction toward the inner side in the axial direction.

Then, the outer peripheral surface 81 and the outer peripheral portions 85 of the respective end portions are formed.
An angle θ1 formed by a surface (that is, an axial end face, the same applies hereinafter) formed from the radially outer end portion 82a toward the radially inner side is greater than 90 ° and less than 180 °,
The radius of curvature R1 of each end outer peripheral portion 85 is formed to be 2 mm or more.

When the primary cleaning roller 54 thus formed is in pressure contact with the photosensitive drum 28 along the axial direction, the radially outer ends 82a of the roller portion 54b are moved in the axial direction. Except for the outer peripheral surface 81,
The roller portions 54b have the same radial thickness (the thickness from the outer peripheral surface to the outer peripheral surface 81 of the roller shaft 54a in the direction orthogonal to the axial direction of the roller shaft 54a), and the surface is formed of a foamed surface. Therefore, from the photosensitive drum 28,
It receives equal reaction forces F2 and F3 with respect to the pressure contact force.

On the other hand, the skin layer 8 is formed on each roller end portion 82.
3 is formed, the rigidity of the roller end portion 82 is higher than the rigidity of the roller portion 54b formed of only the foam layer. However, at each roller end portion 82, the angle θ1 formed by the outer peripheral surface 81 and the axial end surface is 90
It is formed to be larger than 180 ° and less than 180 °. Therefore, when each roller end portion 82 is brought into pressure contact with the photosensitive drum 28, each end outer peripheral portion 85 bends so as to fall inward in the axial direction, so that the reaction force from the photosensitive drum 28 is relaxed. Therefore, the reaction forces F2 and F3 received by the outer peripheral surface 81 excluding the radially outer end portions 82a and the reaction force F1 received by the radially outer end portions 82a can be equalized.
The primary cleaning roller 54 can be uniformly pressed against the photosensitive drum 28.

In order to manufacture such a primary cleaning roller 54, first, after placing the roller shaft 54a in a predetermined die 86 as shown in FIG. 12 (a),
The foam molding raw material is injected into the mold 86 to perform foam molding.

More specifically, as shown in FIG. 12 (a), the mold 86 is composed of a first mold 87 and a second mold 88 which are composed of two halves.

In the first mold 87 and the second mold 88, a roller forming surface 89 for forming the outer peripheral portion of the roller portion 54b and the respective roller end portions 82 of the roller portion 54b are arranged along the longitudinal direction thereof. End forming surfaces 91 for forming the roller bearings and a bearing portion 90 for receiving the roller shaft 54a.

The roller forming surface 89 is formed in a cylindrical shape along the outer peripheral portion of the roller portion 54b in a state where the first die 87 and the second die 88 are clamped. Further, each end forming surface 91 is an end inner peripheral portion along the direction orthogonal to the axial direction of the roller shaft 54a as described above in the state where the first mold 87 and the second mold 88 are clamped. 84 and a radial outer end 82a with respect to the end inner peripheral portion 84 side are formed in a shape along an arcuate end outer peripheral portion 85 that is directed inward in the axial direction. Further, the bearing 90 is clamped with the first die 87 and the second die 88 so as to be able to receive both ends of the roller shaft 54a in the axial direction on both sides in the longitudinal direction of the roller forming surface 89. In the state, it is formed in an elongated, substantially cylindrical shape.

A raw material injection port 92 for injecting a foam molding raw material is provided in the central portion in the longitudinal direction of the second mold 88.
Is provided so as to penetrate the roller forming surface 89 from the outer surface thereof.

For foam molding of the roller portion 54b of the primary cleaning roller 54, first, the roller shaft 54a is arranged on the bearing portion 90 of the first mold 87, and then the first mold 87 is formed.
And the second mold 88 is clamped. When the first die 87 and the second die 88 are clamped, the bearing portion 90 is closed by the roller shaft 54a, and the roller forming surface 89 and the end portion forming surfaces 91 form the first die 87 and Second mold 8
8 inner peripheral surface is formed. Next, from the raw material inlet 92, a foam molding raw material in which a resin, a foaming agent, a conductive agent, and the like are kneaded in advance is injected into the mold 86, and the mold 86 is heated to a predetermined temperature if necessary, The roller portion 54b is foam-molded.

As the resin used for foam molding, for example, silicone resin, urethane resin, EPD
M resin etc. are mentioned. Examples of the foaming agent include known chemical foaming agents. Examples of the conductive agent include carbon.
The conditions for foam molding are not particularly limited, and known conditions may be applied.

Next, the first die 87 and the second die 88.
After opening the mold and taking out the foam-molded primary cleaning roller 54, a skin layer 83 formed on the outer peripheral portion along the axial direction of the roller part 54b obtained by foam molding.
Are removed, and the foamed surface is exposed as the outer peripheral surface 81 of the roller portion 54b along the axial direction.

That is, at the time of foam molding of the roller portion 54b, the portion where the foamed resin comes into contact with the inner peripheral surface of the mold 86 (that is, the roller forming surface 89 and each end portion forming surface 91), that is, the roller portion. As shown in FIG. 12B, a skin layer 83 is formed on the outer peripheral portion and both end portions of 54b. Therefore, only the skin layer 83 formed on the outer peripheral portion along the axial direction of the roller portion 54b formed by contact with the roller forming surface 89 is removed by polishing.

As a result, as shown in FIG. 3, the outer peripheral surface 81 along the axial direction of the roller portion 54b becomes a foamed surface,
A roller layer 54b in which a skin layer 83 remains at each roller end portion 82 at both ends in the axial direction, and each end surface thereof serves as a skin surface.
It is possible to obtain the primary cleaning roller 54 including.

When the primary cleaning roller 54 is manufactured in this manner, the roller portion 54b is foam-molded in the mold 86, so that a substantially spherical uniform cell (for example, cell diameter 16 μm ± 20 μm, opening) is formed. Rate 70-80
%) Can be formed. Therefore, the primary cleaning roller 54 is attached to the photosensitive drum 2 in the axial direction.
8 and 8 with a uniform pressure contact force.

Moreover, after foam molding, only the skin layer 83 formed on the outer peripheral portion of the roller portion 54b along the axial direction is removed, and only the outer peripheral surface 81 of the roller portion 54b along the axial direction is exposed as the foamed surface. Let That is, only the outer peripheral portion along the axial direction is polished and each roller end portion 8 is
Since No. 2 is not polished, productivity can be improved and cost can be reduced by reducing man-hours.

In the primary cleaning roller 54 thus obtained, since the roller end portions 82 at both axial ends of the roller portion 54b remain the skin layer 83, the roller portion 54b is manufactured at the time of manufacture. By omitting the step of cutting both ends in the axial direction, it is possible to improve productivity and reduce cost.

When the primary cleaning roller 54 is brought into pressure contact with the photosensitive drum 28, even if the roller portion 54b
Even if the skin layer 83 is formed on each roller end portion 82, the reaction force from the photosensitive drum 28 can be relaxed on each roller end portion 82 as described above. Therefore, with a simple configuration that only defines the angle of each roller end portion 82 with respect to the outer peripheral surface 81, strong pressure contact with the photosensitive drum 28 at each roller end portion 82 of the roller portion 54b can be avoided.

Further, in the embodiment shown in FIGS. 3 and 4, each roller end portion 82 has a flat end inner peripheral portion 84 and a flat end inner peripheral portion 84 along the direction orthogonal to the axial direction of the roller shaft 54a. The outer end portion 82a in the radial direction with respect to the side is formed by the end outer peripheral portion 85 having an arcuate section inward toward the inner side in the axial direction. However, as shown in FIG. The outer end portion 82a in the radial direction with respect to 82b is
It may be formed to have an arcuate cross section inward in the axial direction over the entire radial direction.

That is, referring to FIG. 5, in the primary cleaning roller 54, each roller end portion 82 of the roller portion 54b has a radially outer end portion 82a and a radially outer end portion 82a, respectively. The entire portion from the portion 82b to the outer end portion 82a in the radial direction is curved and formed in an arc-shaped cross section so as to be directed inward in the axial direction. The angle θ2 formed by the outer peripheral surface 81 and the surface of each roller end portion 82 that extends radially inward from the radially outer end portion 82a is greater than 90 ° and less than 180 °,
The radius of curvature R2 of each roller end portion 82 is formed to exceed the radius R2 ′ of the primary cleaning roller 54 (that is, the length from the axis of the roller shaft 54a to the outer peripheral surface 81).

In the embodiment shown in FIG. 5 as well, similarly to the embodiment shown in FIGS. 3 and 4, at each roller end 82, the outer peripheral surface 81 and the radially outer end of each roller end 82 are formed. The angle θ2 formed by the surface extending inward in the radial direction from 82a is greater than 90 ° and less than 180 °. Therefore, when each roller end portion 82 is brought into pressure contact with the photosensitive drum 28, each roller end portion 82
Since it bends so as to fall inward in the axial direction, the reaction force from the photosensitive drum 28 is relaxed. Therefore, the reaction force received by the outer peripheral surface 81 excluding the radially outer end portions 82a and the reaction force received by the radially outer end portions 82a can be equalized, and the primary cleaning roller 54 is attached to the photosensitive drum 28. It can be uniformly pressed against.

Further, in the embodiment shown in FIGS. 3 to 5, the radially outer end portion 82a side of each roller end portion 82 in contact with the photosensitive drum 28 is formed into a curved surface.
As shown in FIG. 5, the outer peripheral portion 85 may be formed as a chamfered flat surface.

That is, in FIG. 6, in the primary cleaning roller 54, each roller end portion 82 of the roller portion 54b is radially inward as in the primary cleaning roller 54 shown in FIGS. 3 and 4. End inner circumference 84
Of the roller shaft 54, the outer peripheral portion 85 of the end portion is continuously formed on the outer side in the radial direction, and the inner peripheral portion 84 of the end portion is formed.
It is formed in a plane shape in a direction orthogonal to the axial direction of a.

In this embodiment, the end outer peripheral portion 8
5 is formed by bending in a plane shape from the inner peripheral portion 84 of the end portion toward the inner side in the axial direction, and the outer peripheral surface 81 and the outer peripheral portion 85 of each end portion.
The angle θ3 with the surface of the
And the length L of the outer peripheral portion 85 is 1 m.
It is formed as m or more.

In the embodiment shown in FIG. 6 as well, similar to the embodiment shown in FIGS. 3 to 5, at each roller end 82, the outer peripheral surface 81 and the surface of each end outer peripheral portion 85 form. The angle θ3 is formed to be larger than 90 ° and smaller than 180 °. Therefore, when each roller end portion 82 is brought into pressure contact with the photosensitive drum 28, each end outer peripheral portion 85 is
Since it bends so as to fall inward in the axial direction, the reaction force from the photosensitive drum 28 is relaxed. Therefore, the reaction force received by the outer peripheral surface 81 excluding the radially outer end portions 82a and the reaction force received by the radially outer end portions 82a can be equalized, and the primary cleaning roller 54 is attached to the photosensitive drum 28. It can be uniformly pressed against.

Further, as shown in FIG. 7, the inner peripheral portion 8 of the end portion is
4 is a plane in which the roller outer ends 82a are axially inward with respect to the inner radial end 82b and the inner radial end 82b over the entire radial direction without distinguishing between the outer peripheral portion 85 and the end outer peripheral portion 85. It may be formed in an inclined shape.

That is, referring to FIG. 7, in the primary cleaning roller 54, each roller end portion 82 of the roller portion 54b has a radially outer end portion 82a and a radially inner end portion 82a, respectively. The angle θ4 formed by the outer peripheral surface 81 and the surface of each roller end portion 82 extending from the radially outer end portion 82a toward the radially inner side is axially inward over the entire area from the portion 82b to the radially outer end portion 82a. , 90 ° and less than 180 °.

Also in the embodiment shown in FIG. 7, the roller end portions 82 are
An angle θ2 formed by the outer peripheral surface 81 and the surface of each roller end portion 82 that extends radially inward from the radially outer end portion 82a.
Is larger than 90 ° and smaller than 180 °. Therefore, when each roller end portion 82 is brought into pressure contact with the photosensitive drum 28, each roller end portion 82 bends so as to fall inward in the axial direction, so that the reaction force from the photosensitive drum 28 is relaxed. Therefore, the reaction force received by the outer peripheral surface 81 excluding each radial outer end 82a and each radial outer end 82
The reaction force received by a can be equalized, and the primary cleaning roller 54 can be uniformly pressed against the photosensitive drum 28.

In the above description, the outer peripheral surface 81
And a radially outer end 82a of each roller end 82.
The angles θ1 to θ4 with respect to the surface radially inward from are formed to be greater than 90 ° and less than 180 °, but the opposite, that is, as shown in FIG.
The angle θ5 formed by the surface of each roller end portion 82 from the radially outer end portion 82a toward the radially inner end is 90 °.
If it is less than 0 °, the reaction force from the photosensitive drum 28 can be alleviated even if it is formed to be larger than 0 °.

That is, in the embodiment shown in FIG. 8, each roller end portion 82 of the roller portion 54b extends to the radially inner end portion 82b from the radially inner end portion 82b to the radially outer end portion 82a. On the other hand, the outer end portion 82a in the radial direction faces the outer side in the axial direction, and the outer peripheral surface 81
The angle θ5 formed by the surface of each roller end portion 82 inward in the radial direction from the radially outer end portion 82a is 90.
It is formed in a plane inclined shape that is smaller than 0 ° and larger than 0 °.

Also in the embodiment shown in FIG. 8, the roller end portions 82 are
An angle θ5 formed by the outer peripheral surface 81 and the surface of each roller end portion 82 radially inward from the outer end portion 82a in the radial direction.
Is smaller than 90 ° and larger than 0 °. Therefore, when each roller end portion 82 is brought into pressure contact with the photosensitive drum 28, each roller end portion 82 bends so as to fall outward in the axial direction thereof, so that the reaction force from the photosensitive drum 28 can be alleviated.

In the embodiment shown in FIG. 8, in the above-described manufacturing process, in the step of polishing the skin layer 83 on the outer peripheral portion of the roller portion 54b in the axial direction, the polishing tool is pressed against the roller portion 54b in the radial direction. The pressure may cause the roller end portion 82 to fall outward in the axial direction, and the skin layer 83 of the roller end portion 82 may have a tear-off shape.

In the above embodiment, the outer peripheral surface 81
And a radially outer end 82a of each roller end 82.
The reaction force from the photosensitive drum 28 is relaxed by forming the angles .theta.1 to .theta.5 with the surface directed inward in the radial direction from other than 90.degree .. But,
Even if the angle formed by the outer peripheral surface 81 and the surface of each roller end portion 82 from the radially outer end portion 82a toward the inner side in the radial direction is 90 °, as shown in FIG. 9 and FIG. By providing a recess 93, a protrusion 94, or the like on the end surface of the roller end portion 82 as a stress relaxation portion,
The reaction force from the photosensitive drum 28 can be reduced.

That is, in FIG. 9, each roller end portion 82 is
Are formed in a plane shape along a direction orthogonal to the axial direction of the roller shaft 54a, and the roller end portion 82 is formed on the way from the radially inner end portion 82b to the radially outer end portion 82a.
An annular recess 93 is formed that is recessed in a semicircular cross section from the end face toward the inner side in the axial direction.

Further, in FIG. 10, each roller end portion 82 is
The roller shaft 54a is formed in a planar shape along a direction orthogonal to the axial direction of the roller shaft 54a, and has a semicircular cross section outward in the axial direction on the way from the radially inner end 82b to the radially outer end 82a. An annular projecting portion 94 that projects is formed.

By forming such a stress relaxation portion, when each roller end portion 82 is brought into pressure contact with the photosensitive drum 28,
Since the reaction force from the photosensitive drum 28 can be relaxed at the stress relaxing portion, the reaction force from the photosensitive drum 28 can be favorably relaxed by the simple structure of only providing the stress relaxing portion, so that the roller It is possible to avoid strong pressure contact with the photosensitive drum 28 at each roller end portion 82 of the portion 54b.

In particular, in the embodiment shown in FIG. 9, an annular recess 93 is provided in the roller end portion 82 of the roller portion 54b, and the roller end portion 82 of FIG.
In the embodiment shown in FIG. 0, the roller end portion 8 of the roller portion 54b is
2 only by forming an annular protrusion 94 on the photosensitive drum 28.
Since the reaction force from the photosensitive drum 28 can be relaxed, the stress relaxation portion can be easily formed and the reaction force from the photosensitive drum 28 can be favorably relaxed.

The shapes of the recess 93 and the protrusion 94 are as follows.
The shape is not particularly limited, and may be, for example, a rectangular cross section or a triangular cross section, and the depth H of the recess 93 in the axial direction may be H.
1 and the protrusion length H2 of the protrusion 94 in the axial direction is 1
It is preferable to form it with a thickness of at least mm.

Furthermore, such a concave portion 93 and a protruding portion 9
4, the thickness of the roller portion 54b in the radial direction (the thickness from the outer peripheral surface of the roller shaft 54a to the outer peripheral surface 81 in the direction orthogonal to the axial direction of the roller shaft 54a) at the time of foam molding. ) And the thickness of the skin layer, it is possible to reduce the reaction force from the photosensitive drum 28 at each roller end portion 82 of the roller portion 54b.

That is, in the embodiment shown in FIG. 11, the thickness D1 of the roller portion 54b in the radial direction is set by appropriately selecting the molding conditions during the foam molding described above.
The thickness D2 of the skin layer 83 of each roller end portion 82 is formed to be 3 mm or more and 1 mm or less.

With this molding, since the thickness D2 of the skin layer 83 of each roller end portion 82 is smaller than the radial thickness D1 of the roller portion 54b, each roller end portion 82 of the roller portion 54b is formed. Is pressed against the photosensitive drum 28,
The roller end portions 82 at both axial ends of the roller portion 54b bend to the same extent as the roller portion 54b formed only of the foam layer axially inward of the roller end portion 82, and the reaction force from the photosensitive drum 28 is generated. Can be alleviated. for that reason,
The reaction force from the photosensitive drum 28 is satisfactorily alleviated by a simple method of simply selecting the molding conditions, and each roller end portion 8 is
It is possible to avoid strong pressure contact with the photosensitive drum 28 in 2.

The process unit 22 of this laser printer 1 is provided with the above-mentioned roller portion 54b.
Since the next cleaning roller 54 is pressed against the photosensitive drum 28 uniformly, the surface of the photosensitive drum 28 can be cleaned well, and good development and transfer can be achieved, and good image formation can be achieved. .

Although the foam roller of the present invention has been described as the primary cleaning roller 54 in the above description, the foam roller of the present invention may be, for example, the supply roller 3.
As long as it is a roller formed of foam such as No. 3, it can be applied without particular limitation.

[0142]

As described above, according to the first aspect of the present invention, the step of cutting both axial end portions of the roller portion can be omitted to improve productivity and reduce cost. In addition, it is possible to avoid strong pressure contact with the pressed member at both axial end portions of the roller portion.

According to the second aspect of the invention, the step of cutting both axial end portions of the roller portion can be omitted to improve the productivity and reduce the cost.
With a simple configuration that only defines the angle of the end surface with respect to the outer peripheral surface, the reaction force from the pressed member is satisfactorily relaxed, and strong pressing contact with the pressed member at both axial ends of the roller portion is avoided. be able to.

According to the third aspect of the present invention, the step of cutting both axial ends of the roller portion can be omitted to improve productivity and reduce cost.
By a simple method of only selecting the molding condition, the reaction force from the pressed member can be satisfactorily relaxed, and strong pressure contact with the pressed member at both axial end portions of the roller portion can be avoided.

According to the fourth aspect of the present invention, the reaction force from the pressed member is satisfactorily relaxed by the simple structure in which only the stress relaxation portion is provided, and the axial end portions of the roller portion are satisfactorily relaxed. Strong pressure contact with the pressed member can be avoided.

According to the fifth aspect of the present invention, the reaction force from the pressure-contact member can be satisfactorily relaxed while easily forming the stress relaxation portion by the recess.

According to the invention described in claim 6, the reaction force from the pressed member can be satisfactorily relaxed while easily forming the stress relaxation portion by the protrusion.

According to the seventh aspect of the present invention, the foam roller can be brought into pressure contact with the pressure-contact member with a uniform pressure contact force in the axial direction thereof. Further, since only the outer peripheral portion is processed and the end portion is not processed, it is possible to improve productivity and reduce cost by reducing man-hours.

According to the eighth aspect of the present invention, the outer peripheral surface can be made to be the foamed surface easily and reliably.

According to the ninth aspect of the present invention, the cleaning roller can be brought into uniform pressure contact with the pressed member to achieve good cleaning.

According to the tenth aspect of the present invention, since it can be brought into uniform pressure contact with the image carrier, the surface of the image carrier can be satisfactorily cleaned, and good development and transfer can be achieved. You can

According to the eleventh aspect of the present invention, good image formation can be achieved.

[Brief description of drawings]

FIG. 1 is a side sectional view of an essential part showing an embodiment of a laser printer as an image forming apparatus of the present invention.

FIG. 2 is a side sectional view showing a process unit of the laser printer shown in FIG.

FIG. 3 is a cross-sectional view of a cleaning roller of the laser printer shown in FIG.

4 is an enlarged cross-sectional view of a contact portion between a cleaning roller and a photosensitive drum of the laser printer shown in FIG.

FIG. 5 is another embodiment of the cleaning roller of the laser printer shown in FIG. 1 (each roller end is radially inward, and the radially outer end is axially inward with respect to the radially inner end. FIG. 7 is an enlarged cross-sectional view of a contact portion with the photosensitive drum at an end portion (curved in an arc shape in cross section).

FIG. 6 is an enlarged cross-sectional view of a contact portion of the cleaning roller of the laser printer shown in FIG. 1 with the photosensitive drum at the end of the other end (the end outer circumference of the roller end is formed as a chamfered flat surface). It is a figure.

FIG. 7 is another embodiment of the cleaning roller of the laser printer shown in FIG. 1 (each roller end extends radially inward, with the radially outer end directed axially inward with respect to the radially inner end). FIG. 3 is an enlarged cross-sectional view of a contact portion with the photosensitive drum at an end portion (formed in an inclined plane).

FIG. 8 is another embodiment of the cleaning roller of the laser printer shown in FIG. 1 (each roller end has a radius relative to the radially inner end over the entire radially inner end to the radially outer end). FIG. 3 is an enlarged cross-sectional view of an end portion in the direction outer side, which is formed in an inclined plane so as to extend outward in the axial direction).

9 is another embodiment of the cleaning roller of the laser printer shown in FIG. 1 (an annular recess is formed in the roller end portion, which is recessed in a semicircular cross section from the end surface of the roller end portion toward the inner side in the axial direction). FIG. 3 is an enlarged cross-sectional view of a contact portion with the photosensitive drum at the end portion of FIG.

10 is another embodiment of the cleaning roller of the laser printer shown in FIG. 1 (a roller end portion is formed with an annular protrusion that protrudes from the end surface of the roller end portion toward the axially outer side in a semicircular cross section). 3 is an enlarged cross-sectional view of a contact portion with the photosensitive drum at an end portion of FIG.

FIG. 11 is an enlarged cross-sectional view of a contact portion of the cleaning roller of the laser printer shown in FIG. 1 at the end portion of the other embodiment (adjusting the thickness of the roller portion in the radial direction and the thickness of the skin layer) with the photosensitive drum. It is a figure.

12A and 12B are schematic explanatory views of a method of molding the cleaning roller of the laser printer shown in FIG. 1, in which FIG. 12A is a sectional view of a mold forming a roller portion of the primary cleaning roller, and FIG. FIG. 4 is a cross-sectional view of the primary cleaning roller after foam molding and in a state where a skin layer is formed on the outer peripheral portion along the axial direction and the end portions of each roller.

[Explanation of symbols]

1 laser printer 22 Process unit 28 Photosensitive drum 54 Primary cleaning roller 54a roller shaft 54b Roller part 81 outer peripheral surface 82 Roller end 83 Skin layer 86 mold 93 recess 94 Projection

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 2H134 GA01 GB02 HA01 HA12 HA17                       HA18 KD02 KD04 KD05 KD07                       KD08 KE02 KG08 KH10                 2H171 FA30 GA04 JA10 PA04 QA02                       QB02 QB15 QB41 QC03 QC23                       QC25 UA03 UA04 UA08 UA12                       VA02 VA06 XA02                 3J103 AA02 AA13 AA74 BA41 EA02                       FA15 GA02 GA57 GA58 GA60                       GA64 HA03 HA53

Claims (11)

[Claims] 1. A foam roller comprising a shaft portion and a roller portion made of a foam provided around the shaft portion along the axial direction of the shaft portion, wherein an outer peripheral surface of the roller portion along the axial direction. Is a foamed surface, and a skin layer is formed at each end in the axial direction of the roller portion, each end surface being a skin surface, and both end portions in the axial direction of the roller portion are arranged in the axial direction of the roller portion. A foam roller, wherein the foam roller is formed so that a reaction force from the pressed member is relaxed when pressed against the pressed member. 2. A foam roller comprising a shaft part and a roller part made of a foam provided around the shaft part along the axial direction of the shaft part, wherein an outer peripheral surface of the roller part along the axial direction. Is a foamed surface, and a skin layer whose end faces are skin surfaces is formed at both axial end portions of the roller portion, and both axial end portions of the roller portion are arranged in the axial direction of the roller portion. A foam roller, characterized in that an angle formed between the outer peripheral surface and the axial end surface of the roller portion is larger than 90 ° and smaller than 180 °. 3. A foam roller comprising a shaft part and a roller part made of a foam provided around the shaft part along the axial direction of the shaft part, wherein an outer peripheral surface of the roller part along the axial direction. Is a foamed surface, and skin layers each having an end surface as a skin surface are formed at both ends in the axial direction of the roller portion, and the roller portion has a radial thickness of 3 mm or more. A foam roller, characterized in that the layer thickness is 1 mm or less. 4. The foam according to claim 1, wherein stress relieving portions for relieving the reaction force are formed on both axial end surfaces of the roller portion. Body roller. 5. The foam according to claim 4, wherein the stress relieving portion is an annular recess formed on both end surfaces of the roller portion in the axial direction and recessed toward the inner side in the axial direction. roller. 6. The foam according to claim 4, wherein the stress relaxation portion is an annular protrusion formed on both axial end surfaces of the roller portion and protruding outward in the axial direction. Body roller. 7. The shaft portion is arranged in a predetermined die, and a foam molding raw material is injected into the die to perform foam molding, and then only the outer peripheral portion of the roller portion along the axial direction is processed. The foam roller according to any one of claims 1 to 6, which is obtained by: 8. After the foam molding, the skin layer formed on the outer peripheral portion of the roller portion along the axial direction is removed.
The foam roller according to claim 7, wherein a foam surface is exposed as an outer peripheral surface of the roller portion along the axial direction. 9. A cleaning roller provided in an image forming apparatus, comprising the foam roller according to any one of claims 1 to 8. 10. A process apparatus including an image carrier, comprising a cleaning roller for cleaning the surface of the image carrier, wherein the cleaning roller is the foam roller according to any one of claims 1 to 8. Process equipment characterized in that 11. An image forming apparatus comprising the process apparatus according to claim 10.