JP2001242697A - Developing device and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a developing device in which a developing roller can be preferably recycled and development without irregular density can be performed and to provide an image forming device equipped with that developing device. SOLUTION: The developing roller 24 is formed without adhering the roller axis 24 and the roller part 24b, and a polymer toner is used as the toner. In the recycling process, the roller axis 24a can be easily separated from the roller part 24b. In the process of forming an image, even when the developing roller 24 is pressed by a layer thickness regulating blade 25, the polymer toner having good fluidity acts as a roller between the roller 24 and the blade 25 to decrease the frictional force between them. Thus, slipping between the roller axis 24a and the roller part 24b caused by the friction can be effectively prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a laser printer.

[0002]

2. Description of the Related Art In an image forming apparatus such as a color laser printer, a single non-magnetic toner of each color of cyan, magenta, yellow and black is applied to one photosensitive drum on which an electrostatic latent image is formed. There is a known one provided with a plurality of process cartridges to be accommodated. Each process cartridge is provided with a toner storage chamber for storing toner, a supply roller for supplying toner, a developing roller for carrying toner, and a layer thickness regulating blade for pressing the developing roller to form a thin layer of toner. Have been.

In such a laser printer,
In each process cartridge, the toner contained in the toner containing chamber is supplied to the developing roller by a supply roller, and is carried in a thin layer on the developing roller by a layer thickness regulating blade. By successively opposing the drum, the toner carried on each developing roller is selectively transferred to an electrostatic latent image formed on the photosensitive drum, and a visible image is formed for each color, The multi-color image is formed by successively superposing these on the intermediate transfer belt or the intermediate transfer drum.

On the other hand, in recent years, as environmental problems have become more important, recycling of process cartridges, which are frequently replaced, has been studied for such laser printers.
Some have been implemented. In the recycling of the process cartridge, the developing roller has a shaft made of metal while the roller portion is made of an elastic material. It has been considered to separate them from each other, discard the deteriorated roller portion, and attach a new roller portion to the shaft for recycling. In particular, in a color laser printer, since a plurality of process cartridges are provided and a large number of developing rollers are discarded, it is very important to recycle the developing rollers.

[0005] In the developing roller, the shaft and the roller portion are usually fixed by adhesion or fusion-fixing. However, if the roller is fixed by adhesion or fusion-fixing in the case of recycling, when the roller portion is peeled off from the shaft. Therefore, it is necessary to use an organic solvent, which adversely affects the environment. Therefore, it is desired that the roller is mounted without being adhered to the shaft, for example, by press-fitting the roller into the shaft.

Depending on the degree of deterioration of the collected developing roller, it may be used as it is in the next process cartridge. For example, in order to prevent toner leakage from the developing roller, a seal is provided on the end of the developing roller. In the case where the member is rubbed, the peripheral surface of the end portion of the developing roller is damaged by the sealing member.
If the toner is reused as it is, the toner leaks from the scratched portion, and it is difficult to reuse the toner as it is.

[0007]

On the other hand, in a laser printer using a non-magnetic one-component toner as described above, the developing roller is pressed by the layer thickness regulating blade. Otherwise, a slip occurs between the shaft and the roller portion due to the frictional force of this portion, causing a problem that uneven density appears in the image.

That is, such a slip is likely to occur particularly immediately after the start of rotation of the developing roller, that is, in a state where a static friction coefficient which is much larger than the dynamic friction coefficient is acting. When each developing roller is opposed to the photosensitive drum, that is, at the same time as or before and after the image forming timing, when slipping, the effect appears directly on the image and the visible image is superimposed. In a multicolor image, there is a problem that the image appears as uneven density.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has as its object to develop a developing device capable of satisfactorily recycling a developing roller and achieving development without uneven shading. An object of the present invention is to provide an image forming apparatus provided with the developing device.

[0010]

In order to achieve the above object, according to the first aspect of the present invention, there is provided a developer carrying member for carrying a non-magnetic one-component developer, and pressing on the developer carrying member. And a layer-thickness regulating member for forming a thin layer of the developer, wherein the developer carrier has a metal shaft and a conductive elastic body covering the shaft. The shaft and the elastic layer are not adhered to each other, and the developer is a polymerized toner obtained by polymerizing a polymerizable monomer.

According to such a configuration, since the shaft of the developer carrying member and the elastic layer are not bonded, the shaft and the elastic layer can be easily separated from each other. The recycling of the developer carrier can be achieved. Further, since the developer carrier is pressed by the layer thickness regulating member, if the shaft and the elastic layer are not bonded,
Slip tends to occur between the shaft and the elastic layer due to the frictional force at this portion. However, in this configuration, since the developer is a polymerized toner having good fluidity, the polymerized toner is used as a layer thickness regulating member. It acts as a roller between the developer and the developer carrier, and acts to reduce the frictional force at this portion. As a result, even if the shaft of the developer carrying member and the elastic layer are not adhered to each other, slip between them is prevented, and good image formation without uneven density can be achieved.

The invention described in claim 2 is the first invention.
In the invention described in (1), the elastic layer is mainly composed of silicone rubber.

[0013] Silicone rubber has a lower mechanical strength than urethane rubber and the like, so that in recycling the developer carrier, the elastic layer is easily cut, and the shaft and the elastic layer are separated well. be able to. On the other hand, in image formation, slipping is more likely to occur between the shaft of the developer carrier and the elastic layer, but the polymerized toner reduces the frictional force between the layer thickness regulating member and the developer carrier. Therefore, even if the elastic layer is mainly composed of silicone rubber, the slip between them can be effectively prevented, and a good image can be formed without uneven density.

[0014] The invention according to claim 3 provides the invention according to claim 1.
In the invention described in (2), a conductive coat layer is provided on an outer peripheral portion of the elastic layer, and the resistance of the coat layer has a higher resistance than the resistance of the elastic layer. It is characterized by doing.

According to such a configuration, for example, a floating occurs between the shaft and the elastic layer that are not bonded to each other,
Even if the resistance value of that part becomes higher, the resistance value of the coat layer is configured to be higher than the resistance value of the elastic layer, so that it is possible to prevent development defects due to the floating, and to prevent image failure. Impact on the vehicle can be reduced.

Further, the invention according to claim 4 is the same as the invention according to claim 3.
In the invention described in (1), the coating layer contains fluorine.

When the coating layer contains fluorine, the friction coefficient of the surface of the developer carrier can be significantly reduced. Therefore, the frictional force between the layer thickness regulating member and the developer carrier can be further reduced, and the slip between the shaft and the elastic layer in the developer carrier can be further prevented.

According to a fifth aspect of the present invention, in the invention according to any one of the first to fourth aspects, a pressing portion of the layer thickness regulating member for pressing the developer carrier is a rubber elastic body or It is characterized by being constituted by a rubber elastic body having a coating layer provided on the surface.

According to this configuration, when the developer carrying member is pressed by the layer thickness regulating member, the pressed portion is deformed, and the deformation of the pressed portion of the developer carrying member can be reduced. . Therefore, for example, when the deformation of the pressed portion of the developer carrier is large, a large torque is generated at the start of driving of the developer carrier, and a large torque is generated between the shaft of the developer carrier and the elastic layer. Slip is likely to occur, but such slip at the start of driving of the developer carrier can be effectively prevented. Polymerized toner has low mechanical strength,
Since the pressing force is reduced by the deformation of the pressing portion, the deterioration of the polymerized toner can be effectively prevented.

According to a sixth aspect of the present invention, there is provided an image forming apparatus including the developing device according to any one of the first to fifth aspects.

With such a developing device, the developer carrier can be recycled well,
It is possible to provide an environment-friendly image forming apparatus capable of achieving good image formation without uneven density.

The invention described in claim 7 is the same as the invention in claim 6
The present invention is characterized in that a plurality of the developer carrying members and the layer thickness regulating members are provided so as to be capable of forming a multicolor image.

According to such a configuration, a multicolor image of good image quality without density unevenness can be formed. Also,
Since all of the plurality of developer carriers can be satisfactorily recycled, the number of developer carriers discarded can be significantly reduced, and the effect on the environment can be greatly reduced.

The invention according to claim 8 is the same as the invention according to claim 6.
Or in the invention according to 7, wherein a photoconductor on which an electrostatic latent image is formed, a developing position for bringing the developer carrier closer to the photoconductor, and a retracting position for separating the developer carrier from the photoconductor. And moving means for enabling the moving of the moving object.

According to such a construction, the developer carrier is located at the developing position close to the photosensitive member during development by the moving means, and separated from the photosensitive member during non-development. Is operated to be located at the retracted position.
At the time of this development, the developer carrier usually starts to be driven at substantially the same timing. Therefore, if a slip occurs between the shaft of the developer carrier and the elastic layer, the effect is as follows.
It appears directly in the image, and especially in a multicolor image in which a visible image is superimposed, it appears as uneven density. However, in the present invention, since the occurrence of a slip between the shaft of the developer carrying member and the elastic layer is well prevented, it is possible to effectively prevent such an image defect caused by the slip. it can.

The invention according to claim 9 is a non-magnetic one.
A developer carrying member for carrying the developer of the component; and a layer thickness regulating member for pressing the developer carrying member to form a thin layer of the developer. Is constituted by a metal shaft and an elastic layer made of a conductive elastic body that covers around the shaft, and the shaft and the elastic layer are not adhered to each other. The pressing portion for pressing the developer carrier is made of a rubber elastic body or a rubber elastic body having a coating layer provided on a surface thereof.

According to such a configuration, since the shaft of the developer carrying member and the elastic layer are not adhered, the shaft and the elastic layer can be easily separated from each other. The recycling of the developer carrier can be achieved. Further, since the pressing portion of the layer thickness regulating member is made of a rubber elastic body, or a rubber elastic body having a coating layer provided on the surface, when the layer thickness regulating member presses the developer carrier, the pressure is reduced. The pressed portion is deformed, and the deformation of the pressed portion of the developer carrier can be reduced. Therefore, for example, when the deformation of the pressed portion of the developer carrier is large, a large torque is generated at the start of driving of the developer carrier, and a large torque is generated between the shaft of the developer carrier and the elastic layer. Slip is likely to occur, but such slip at the start of driving of the developer carrier can be effectively prevented.

According to a tenth aspect of the present invention, there is provided an image forming apparatus including the developing device according to the ninth aspect.

By providing such a developing device, the developer carrier can be satisfactorily recycled, and
It is possible to provide an environment-friendly image forming apparatus capable of achieving good image formation without uneven density.

[0030]

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

In FIG. 1, a color laser printer 1 includes a paper feed unit 3 for feeding paper, an image forming unit 4 for forming an image, and a discharge A paper unit 39 and the like are provided.

The paper feed unit 3 is disposed above the main body casing 2 and has a paper feed tray 5 for stacking paper in a stacking state and a paper feed tray for feeding paper stacked on the paper feed tray 5. The image forming apparatus includes a paper roller 6 and a registration roller 7 provided downstream of the paper supply roller 6 in the paper transport direction. A sheet pressing plate 9, one end of which is urged by a spring 8 toward a sheet feeding roller 6, is swingably supported in the sheet feeding tray 5. A certain sheet is fed one by one by the rotation of a sheet feeding roller 6, and the sheet sent from the sheet feeding roller 6 is subjected to a predetermined registration by a pair of registration rollers 7 before an image forming unit 4 described below. To send to.

The image forming unit 4 includes a scanner unit 10, a developing unit 11, and a fixing unit 12. The scanner unit 10 is provided in the upper part of the main body casing 2 and below the sheet feeding unit 3, and includes a laser emitting unit (not shown), a polygon mirror 13 that is driven to rotate, lenses 14 and 15, and a reflecting mirror 16. And 17
A laser beam based on predetermined image data emitted from the laser emitting section is passed or passed in the order of the polygon mirror 13, the lens 14, the reflecting mirror 16, the lens 15, and the reflecting mirror 17 as shown by arrows. Let it reflect
Irradiation is performed on the surface of the photosensitive drum 18 of the developing unit 11 described later by high-speed scanning.

The developing unit 11 is disposed below the scanner unit 10 in the main body casing 2, and includes a photosensitive drum 18 as a photosensitive member, a rotary developing unit 19 as moving means, a scorotron charger 20, and an intermediate transfer belt 2.
1, a transfer roller 22 and the like.
The rotary developing unit 19 is disposed upstream of the intermediate transfer belt 21 in the sheet conveyance direction.

The rotary developing unit 19 includes a photosensitive drum 18
The developing cartridge 23 is disposed on the upstream side in the sheet conveyance direction, has a cylindrical shape,
That is, the cyan developing cartridge 23C, the magenta developing cartridge 23M, and the yellow developing cartridge 23M
The Y and black developing cartridges 23K are detachably mounted. Each of the developing cartridges 23 includes a developing roller 24 as a developer carrier, a layer thickness regulating blade 25 as a layer thickness regulating member, a supply roller 26, and a toner storage chamber 27. The rotary developing unit 19 is rotated in a direction indicated by an arrow (clockwise) by rotation of a drive shaft 28 provided at the center so that the developing roller 24 provided on each developing cartridge 23 can sequentially face the photosensitive drum 18. It is rotatable.

FIG. 2 is an enlarged side sectional view showing a main part of the developing cartridge 23. In FIG. 2, the toner storage chamber 27
Each of the developing cartridges 23 is filled with a positively-charged non-magnetic one-component toner as a developer having a color of cyan, magenta, yellow, and black. As the toner, polymerizable monomers, for example, styrene-based monomers such as styrene, acrylic acid,
Alkyl (C1-C4) acrylate, alkyl (C1
To C4) an acrylic monomer such as methacrylate,
Polymerized toners obtained by copolymerization by a known polymerization method such as suspension polymerization are used. Such a polymerized toner has a very good fluidity because its shape is spherical compared to a pulverized toner. In addition,
Such a toner is blended with a coloring agent such as carbon black, a wax, and the like, and an external additive such as silica is added to improve fluidity. The particle size is about 6 to 10 μm.

The toner is agitated by an agitator 29 rotatably provided in the toner storage chamber 27 and is discharged from a toner supply port 30 opened on the side of the toner storage chamber 27.

A supply roller 26 is rotatably disposed at a position lateral to the toner supply port 30. A developing roller 24 is rotatably disposed opposite the supply roller 26. I have. The supply roller 26 and the developing roller 24 are in contact with each other in a state where each of them is compressed to some extent. The developing roller 2
Numeral 4 is configured so that its rotation direction rotates from top to bottom in a development area facing the photosensitive drum 18.

The supply roller 26 has a metal roller shaft 26.
a and a roller portion 26b made of a conductive foam material that covers the periphery of the roller shaft 26a.

The developing roller 24 includes a metal roller shaft 24a and a roller portion 24b as an elastic layer made of a conductive elastic material and covering the periphery of the roller shaft 24a. Roller shaft 24a and roller part 2
4b is not adhered, for example, the roller portion 2
The roller shaft 24a is mounted by being pressed into the roller shaft 24a. Further, more specifically, the roller portion 24b
The roller portion 24b is provided with a coating layer 24c made of urethane rubber containing fluorine on the outer peripheral portion of the roller portion 24b. 2
The electric resistance value of the roller portion 4c is higher than the electric resistance value of the roller portion 24b. A bias is applied to the roller shaft 24a of the developing roller 24 so that a predetermined potential difference is applied between the roller shaft 24a and the photosensitive drum 18.

In the vicinity of the developing roller 24, a layer thickness regulating blade 25 is provided so as to press on the developing roller 24. This layer thickness regulating blade 25
A blade body 25a made of a metal leaf spring material, and a pressing portion 25b provided at the tip of the blade body 25a and having a semicircular cross section made of insulating silicone rubber are provided. The end opposite to the developing roller 24 is supported by the frame of the developing cartridge 23 near the developing roller 24, and the pressing portion 25b is pressed against the developing roller 24 by the elastic force of the blade body 25a. . In addition,
The pressing portion 25b may be provided with a coat layer on the surface.

The toner discharged from the toner supply port 30 is supplied to the developing roller 2 by the rotation of the supply roller 26.
4, the supply roller 26 and the developing roller 2
4 and the developing roller 26
The toner supplied above enters between the pressing portion 25b of the layer thickness regulating blade 25 and the developing roller 24 with the rotation of the developing roller 24, which will be described later, where the toner is further sufficiently triboelectrically charged and fixed. Developing roller 24 as a thin layer having a thickness of
Carried on top. During development, since the layer thickness regulating blade 25 is disposed above the supply roller 26, the toner scraped from the developing roller 24 by the layer thickness regulating blade 25
It falls down and becomes supplied again by the supply roller 26.

On the other hand, as shown in FIG.
Is provided at a side position of the rotary developing unit 19 so as to be opposed to the developing roller 24 of each developing cartridge 23, and is rotatable in an arrow direction (clockwise direction). The photosensitive drum 18 has a drum body grounded, and has a surface formed of a positively chargeable material such as an organic photoreceptor containing polycarbonate as a main component. Further, the scorotron type charger 20 is disposed above the photosensitive drum 18 at a predetermined interval. The scorotron charger 20 is a positive scorotron charger for generating corona discharge from a charging wire such as tungsten, and is configured to uniformly positively charge the surface of the photosensitive drum 18. Have been. And
After the surface of the photosensitive drum 18 is uniformly positively charged by the scorotron charger 20, it is exposed by high-speed scanning of a laser beam from the scanner unit 10 to form an electrostatic latent image based on predetermined image data. .

Then, by the rotation of the rotary developing unit 19, the developing roller 24 of each developing cartridge 23 is brought into contact with the photosensitive drum 18 to be positioned at a developing position facing the photosensitive drum 18, and at the same time, the developing roller 24 is brought into contact with the facing photosensitive drum 18 By rotating the contact portion in the same direction, the toner carried on the developing roller 24 and positively charged becomes an electrostatic latent image formed on the surface of the photosensitive drum 18, that is, a uniformly positively charged toner. The surface of the photosensitive drum 18 is exposed to a laser beam and has a lower potential, and is selectively transferred to a visible image to be developed into a visible image, thereby achieving development (reversal development). In this embodiment, when the developing roller 24 of a certain developing cartridge 23 comes into contact with the photosensitive drum 18 and is located at the developing position by the rotation of the rotary developing unit 19, the developing roller 24 is moved to the developing position before the rotation starts. The developing roller 24 of the developing cartridge 23 that has been positioned is now located at the retracted position that is separated from the photosensitive drum.

Next, the visible image of each color formed on the photosensitive drum 18 is sequentially transferred to the intermediate transfer belt 21 facing the photosensitive drum 18.

The intermediate transfer belt 21 is disposed so as to face the side of the photosensitive drum 18. The intermediate transfer belt 21 is located downstream of the registration roller 7 in the sheet conveyance direction so as to face the sheet conveyance path. And a first roller 31 provided below the registration roller 7 below the horizontal direction.
And below the first roller 31, the photosensitive drum 1
A second roller 32 provided in the vicinity of the second roller 3 and a second roller 3
And a third roller 33 provided further below at a predetermined distance from the second roller. The first to third rollers 31 to 33 are arranged such that the first roller 31 is the highest and the third roller 33 is the lowest. They are arranged in a substantially triangular shape. An endless belt 34 is wound around the first to third rollers 31 to 33, and the photosensitive drum 18 is disposed between the first and second rollers 31 and 32.
It can be moved in the direction of the arrow (counterclockwise) in such a state as to come into contact with. The material of the endless belt 34 is
Resins such as conductive polycarbonate and polyimide are used.

The visible image formed on the photosensitive drum 18 is
The photosensitive drum 1 is disposed between the first roller 31 and the second roller 32.
Endless belt 34 that moves in the same direction as the rotation direction 8
Transcribed above.

By rotating the rotary developing unit 19, the developing roller 24 of each developing cartridge 23 is positioned at the developing position, and is sequentially opposed to the photosensitive drum 18, so that a visible image of each color is formed on the photosensitive drum 18. Is formed, and a visible image of each color is sequentially superimposed on the endless belt 34 of the intermediate transfer belt 21 to form a multicolor image.

That is, for example, the rotary developing unit 1
When the developing roller 24 of the cyan developing cartridge 23C is located at the developing position and faces the photosensitive drum 18 by the rotation of 9, the visible image is formed on the photosensitive drum 18 by the cyan toner filled in the cyan developing cartridge 23C. And is transferred onto the endless belt 34 of the intermediate transfer belt 21. Note that the black developing cartridge 23 that was located at the developing position before the rotation started
The K developing roller 24 is located at a retracted position separated from the photosensitive drum. When the developing roller 24 of the magenta developing cartridge 23M is positioned at the developing position by the rotation of the rotary developing unit 19 again and faces the photosensitive drum 18, the photosensitive drum 18 is filled with the magenta toner filled in the magenta developing cartridge 23M. A visible image is formed on the intermediate transfer belt 21. The visible image is formed on the endless belt 34 of the intermediate transfer belt 21 on which the cyan toner image has already been transferred. And the black toner filled in the black developing cartridge 23K, thereby forming a multicolor image on the endless belt 34 of the intermediate transfer belt 21.

The transfer roller 22 is rotatably disposed above the intermediate transfer belt 21 and at a position facing the first roller 31 of the intermediate transfer belt 21 via a sheet. The transfer roller 22 includes a metal roller shaft and a roller portion made of a conductive elastic material that covers the periphery of the roller shaft, so that a predetermined potential difference is given between the transfer roller 22 and the intermediate transfer belt 21. Transfer bias is applied.

The multicolor image formed on the intermediate transfer belt 21 is collectively transferred to the paper while the paper passes between the intermediate transfer belt 21 and the transfer roller 22, and thereafter, the transferred paper is The sheet is conveyed to the fixing unit 12 described below.

The first roller 3 of the intermediate transfer belt 21
No. 1 is formed to have a radius of curvature of 20 mm or less. If the radius of curvature of the first roller 31 is set to be equal to or less than 20 mm, the leading end of the sheet is satisfactorily separated from the first roller 31 after passing between the transfer roller 22 and the first roller 31. Thereby, for example, the first roller 3
Unlike the case where the radius of curvature of the first roller 31 is increased, the sheet can be satisfactorily conveyed to the fixing unit 12 without being wound around the surface of the first roller 31.

The fixing unit 12 includes an intermediate transfer belt 21
Downstream of the sheet transport direction with respect to
The heating roller 35 is disposed below the horizontal direction with respect to 2, and includes a heating roller 35 and a pressing roller 36 pressed by the heating roller 35. The heating roller 35 is made of metal and includes a halogen lamp for heating, and passes the multicolor image transferred on the sheet in the image forming unit 4 between the heating roller 35 and the pressing roller 36. The heat is fixed in between.

The paper discharge unit 39 is located downstream of the fixing unit 12 in the sheet conveyance direction, and
2, and includes a paper discharge roller 37 and a paper discharge tray 38. Then, the fixing unit 12
The sheet on which the multicolor image is thermally fixed is discharged onto a discharge tray 38 by a pair of discharge rollers 37.

Further, a paper feed roller 5, a registration roller 7,
First roller 31, transfer roller 22, fixing unit 1
2 and the paper discharge roller 37 are arranged substantially linearly in order from top to bottom to form a paper transport path. Therefore, after the paper fed by the paper feed roller 5 is conveyed after a predetermined registration by the registration roller 7, while passing between the first roller 31 and the transfer roller 22, the paper After the color images are collectively transferred, and the multicolor image is thermally fixed by the fixing unit 12, the sheet is discharged onto a discharge tray 38 by a pair of discharge rollers 37.

The color laser printer 1 includes:
A cleaner 40 is provided as a cleaning member that collects the toner remaining on the endless belt 34 after the multicolor images are collectively transferred to the sheet.

The cleaner 40 is disposed below the intermediate transfer belt 21 so as to face the third roller 33, and has a collection box 42 having an opening formed at an upper portion thereof, and is provided at an opening of the collection box 42. And a cleaning blade 41 that can be used. Cleaning blade 41
Is provided to face the third roller 33 of the intermediate transfer belt 21 from below, and is arranged so as to be able to contact the surface of the endless belt 34 that moves upward from below. Then, the toner remaining on the endless belt 34 is scraped off by the cleaning blade 41 and collected in the collection box 42. Although not shown in the drawing, the cleaner 40 is provided so as to be vertically movable so as to be able to contact or separate from the endless belt 34. During the image forming operation, the cleaner 40 is provided. The cleaning blade 41 is moved downward and the cleaning blade 41 is separated from the endless belt 34. After the image forming operation is completed, the cleaning blade 41 is moved upward to move the cleaning blade 41 upward.
To collect the residual toner on the endless belt 34.

At the time of collection, the cleaning blade 41 is disposed so as to contact the surface of the endless belt 34 which is directed upward from below. When the belt 34 is separated,
Since the scraped toner falls as it is under its own weight, it does not accumulate on the surface of the endless belt 34 in a streak shape, and a good image can be formed.

The cleaner 40 is also provided on the side of the photosensitive drum 18, and after each visible image is sequentially transferred to the intermediate transfer belt 21 by the rotation of the photosensitive drum 18,
The toner remaining on the photosensitive drum 18 is scraped off by a cleaning blade 41 arranged so as to be in contact with the surface of the photosensitive drum 18 rotating from below to above. The cleaner 40 is formed integrally with the casing of the scorotron charger 20.

In the thus configured color laser printer 1 of the present embodiment, when the toner of each color runs out, the developing cartridge 23 of the missing color is appropriately replaced and used. The replacement frequency of the cartridge 23 is relatively high, and therefore, the developing cartridge 23 is recycled and used. In such recycling, the developing roller 24 provided in each developing cartridge 23 includes a roller shaft 24a.
The roller shaft 24a and the roller portion 24b are mounted by press-fitting without being bonded.
And can be easily separated. Therefore, the roller shaft 24a and the roller portion 2 are separated from the collected developing roller 24.
4b, the deteriorated roller portion 24b is discarded, and a new roller portion 24b is attached to the roller shaft 24a.
By mounting the developing roller, good recycling of the developing roller 24 is achieved.

In particular, in the present embodiment, since the roller portion 24a is made of conductive silicone rubber containing fine carbon particles and the like, its mechanical strength is lower than that of urethane rubber or the like. In this case, the roller portion 24a can be easily cut, and the roller shaft 24a and the roller portion 24b can be separated well.

On the other hand, when the developing roller 24 is formed by press-fitting without bonding the roller shaft 24a and the roller portion 24b, the developing roller 24 has a layer thickness during image formation. The roller shaft 24a is pressed by the regulating blade 25,
Between the roller portion 24b and the roller portion 24b,
In the present embodiment, since the polymerized toner having good fluidity is used, the polymerized toner plays a role of a roller between the layer thickness regulating blade 25 and the developing roller 24, and the frictional force of this portion is used. Therefore, even if the roller shaft 24a of the developing roller 24 and the roller portion 24b are not bonded, slipping therebetween is prevented, and a good image is formed without uneven density. Can be achieved. In the present embodiment, the roller portion 24b is made of silicone rubber having a low mechanical strength. During image formation, slippage is more likely to occur between the roller shaft 24a and the roller portion 24b. Such slip is effectively prevented by the polymerized toner.

Further, since a coat layer 24c having an electric resistance higher than the electric resistance of the roller portion 24b is provided on the outer peripheral portion of the roller portion 24b, the rollers which are not adhered to each other are provided. Even if floating occurs between the shaft 24a and the roller portion 24b and the electrical resistance value of that portion increases, the electrical resistance value of the coat layer 24c is configured to be higher. The electrical resistance value of the developing roller 24 does not change, so that the developing failure caused by the floating is prevented, and the effect is not exerted on the image. More specifically, this coat layer 24
Since c is made of urethane rubber containing fluorine, in addition to such an effect, the coefficient of friction of the surface of the developing roller 24 is significantly reduced. Is further reduced, and the roller shaft 24a of the developing roller 24 is further reduced.
Slip between the roller portion 24b and the roller portion 24b is more effectively prevented.

In the present embodiment, the pressing portion 25b of the layer thickness regulating blade 25 is made of insulating silicone rubber.
When the developing roller 25 is being pressed, the pressed portion 25b is deformed so that the pressed portion of the developing roller 25 is less deformed. Therefore, for example, when the pressed portion of the developing roller 25 has a large deformation, a large torque is generated at the start of the rotation of the developing roller 25, and a large torque is generated between the roller shaft 24 a of the developing roller 24 and the roller portion 24 b. Slip is likely to occur, but such slip is effectively prevented. Although the polymerized toner has a low mechanical strength, the pressing portion 25b is deformed to reduce the pressing force, so that the deterioration of the polymerized toner is effectively prevented.

In this embodiment, in order to make the developing roller 24 of each developing cartridge 23 face the photosensitive drum 18, the rotating developing unit 19 is rotated,
Since each developing roller 24 is rotated, a slip between the roller shaft 24a and the roller portion 24b is likely to occur during this development, and the effect appears directly in the image, and the density in the multicolor image is increased. Although unevenness is likely to occur, in the present embodiment, since the occurrence of slip between the roller shaft 24a and the roller portion 24b is successfully prevented as described above, an image defect due to such slip is caused. Is effectively prevented.

The laser printer 1 according to the present embodiment having the above-described configuration can achieve good recycling of the developing cartridge 23 and the developing roller 24 and can form a good image without uneven density. Therefore, it is possible to provide an environmentally friendly and high quality laser printer.

In particular, in the laser printer 1 described above, since all of the four developing rollers 24 can be satisfactorily recycled, the number of the developing rollers 24 to be discarded can be remarkably reduced, and this is given to the environment. The effect can be greatly reduced.

In the present embodiment, the image forming apparatus of the present invention has been described by taking a color laser printer as an example. However, for example, the image forming apparatus of the present invention may be a monochrome printer.

[0069]

As described above, according to the first aspect of the present invention, since the shaft of the developer carrier is not bonded to the elastic layer, the shaft and the elastic layer can be easily separated. , While enabling good recycling of the developer carrier,
Since the polymerized toner acts to reduce the frictional force between the layer thickness regulating member and the developer carrier, even if the shaft of the developer carrier and the elastic layer are not bonded, Slip can be effectively prevented, and good image formation without uneven density can be achieved.

According to the second aspect of the present invention, since the elastic layer is composed of silicone rubber as a main component, the elastic layer can be easily cut in recycling, and the shaft and the elastic layer can be easily separated. Can be separated. On the other hand, in image formation, slipping is more likely to occur between the shaft of the developer carrying member and the elastic layer, but the polymerized toner effectively prevents slippage therebetween, and provides a good image without uneven density. Formation can be achieved.

According to the third aspect of the present invention, for example, even if the shaft that is not adhered to the shaft and the elastic layer are lifted, and the resistance value of that portion is increased, the elastic layer is not damaged. Since the resistance value of the coat layer is configured to be higher than the resistance value, it is possible to prevent poor development due to the floating, and to reduce the influence on the image.

According to the fourth aspect of the present invention, the frictional force between the layer thickness regulating member and the developer carrier can be further reduced, and the distance between the shaft and the elastic layer in the developer carrier can be reduced. Can be further prevented from slipping.

According to the fifth aspect of the invention, the deformation of the developer carrier pressed by the layer thickness regulating member can be reduced, and the shaft of the developer carrier at the start of driving of the developer carrier can be reduced. And the elastic layer can be effectively prevented from slipping. Polymerized toner has low mechanical strength,
Since the pressing force is reduced by the deformation of the pressing portion, the deterioration of the polymerized toner can be effectively prevented.

According to the sixth aspect of the present invention, the developer carrier can be satisfactorily recycled,
It is possible to provide an environment-friendly image forming apparatus capable of achieving good image formation without uneven density.

According to the seventh aspect of the invention, it is possible to form a multicolor image of good image quality without density unevenness.
In addition, since all of the plurality of developer carriers can be satisfactorily recycled, the number of discarded developer carriers can be significantly reduced, and the effect on the environment can be significantly reduced. it can.

According to the eighth aspect of the present invention, at the time of development, the moving means positions the developer carrier at the developing position close to the photoconductor and starts driving the developer carrier. However, since the occurrence of slip between the shaft of the developer carrying member and the elastic layer is well prevented, it is possible to achieve good image formation without causing image defects such as uneven density. .

According to the ninth aspect of the present invention, since the shaft of the developer carrying member and the elastic layer are not bonded, the shaft and the elastic layer can be easily separated from each other, so that a good developer carrying member can be obtained. The developer pressed by the layer thickness regulating member can be recycled and the pressed portion of the layer thickness regulating member is made of a rubber elastic body or a rubber elastic body having a coating layer provided on the surface. The deformation of the carrier can be reduced, and the slip between the shaft and the elastic layer at the start of driving of the developer carrier can be effectively prevented.

According to the tenth aspect of the present invention, it is possible to satisfactorily recycle the developer carrying member and to form a good image without uneven shading. A forming device can be provided.

[Brief description of the drawings]

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

FIG. 2 is an enlarged side sectional view showing a main part of a developing cartridge in the color laser printer shown in FIG.

[Explanation of symbols]

 1 Color Laser Printer 18 Photosensitive Drum 19 Rotary Developing Unit 23 Developing Cartridge 24 Developing Roller 24a Roller Shaft 24b Roller Part 24c Coat Layer 25 Layer Thickness Control Blade 25b Pressing Part

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) F16C 13/00 F16C 13/00 B

Claims (10)

[Claims] 1. A developing device comprising: a developer carrier for carrying a non-magnetic one-component developer; and a layer thickness regulating member for pressing the developer carrier to form a thin layer of the developer. In the apparatus, the developer carrier includes a metal shaft and an elastic layer made of a conductive elastic material that covers the periphery of the shaft, and the shaft and the elastic layer are adhered to each other. Wherein the developer is a polymerized toner obtained by polymerizing a polymerizable monomer. 2. The developing device according to claim 1, wherein the elastic layer is mainly composed of silicone rubber. 3. A coating layer having conductivity is provided on an outer peripheral portion of the elastic layer, and a resistance value of the coating layer is higher than a resistance value of the elastic layer. The developing device according to claim 1, wherein: 4. The developing device according to claim 3, wherein said coat layer contains fluorine. 5. A pressing portion of the layer thickness regulating member that presses the developer carrier is made of a rubber elastic body or a rubber elastic body having a coating layer provided on a surface thereof. The developing device according to claim 1. 6. An image forming apparatus comprising the developing device according to claim 1. 7. The image forming apparatus according to claim 6, wherein a plurality of the developer carrying members and the layer thickness regulating members are provided so as to form a multicolor image. 8. A photosensitive member on which an electrostatic latent image is formed, a developing position for bringing the developer carrier closer to the photosensitive member, and a retractable position for separating the developer carrier from the photosensitive member. The image forming apparatus according to claim 6, further comprising a moving unit configured to: 9. A developing device comprising: a developer carrying member for carrying a non-magnetic one-component developer; and a layer thickness regulating member for pressing the developer carrying member to form a thin layer of the developer. In the apparatus, the developer carrier includes a metal shaft and an elastic layer made of a conductive elastic material that covers the periphery of the shaft, and the shaft and the elastic layer are adhered to each other. A developing device, wherein a pressing portion of the layer thickness regulating member for pressing the developer carrier is made of a rubber elastic body or a rubber elastic body having a coating layer provided on a surface thereof. 10. An image forming apparatus comprising the developing device according to claim 9.