JPH1026886A - Liquid developer removal method for wet-type image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid developer removal method for a wet-type image forming device which obtains a satisfactory image even in case foreign matter is caught between each member and each scraping member. SOLUTION: The wet-type image forming device develops a latent image on a latent-image carrier 1 with liquid developer, removes a residue of the liquid developer supplied to the surface of the latent-image carrier 1, then, electrostatically bonds the toner image onto the latent-image carrier 1, and transfers the toner image to a transfer material P. In the liquid developer removal method for the wet-type image forming device, the scraping members 27, 9a, 10a, 11a, and 23 for scraping the liquid developer are made to abut on the moving surfaces of the members 1, 9, 10, 11, and 21, respectively, with all of which the liquid developer is brought into contact, and at least one of the scraping members is reciprocated in the direction of the generating line of the moving surface which is orthogonal to the direction of the movement of the moving surface.

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 copying machine, a printer and a facsimile apparatus using an electrophotographic system, and more particularly to a wet image forming apparatus using a developing solution in which a toner is dispersed in a liquid carrier. The present invention relates to a developer removing method.

[0002]

2. Description of the Related Art A developing solution in which toner particles are dispersed in a carrier liquid is supplied by a developing roller to an electrostatic latent image formed on a photoreceptor serving as a latent image carrier to form a toner image and transfer the toner image. After removing the excess carrier liquid from the photoreceptor with a squeeze roller, leaving the necessary carrier liquid on the photoreceptor, the toner image is electrostatically bound on the photoreceptor by the binding roller, and the transfer material is transferred onto the transfer belt. 2. Description of the Related Art A wet image forming apparatus that forms an image by transferring a toner image is generally well known.

[0003] A bias voltage is applied to the developing roller so that unnecessary toner does not adhere to the background, and toner particles adhere to the surface of the developing roller. In addition, a scraping member such as a scraper is provided near the developing roller.
Similarly, a scraping member made of a scraper, a blade, a web, or the like is provided near the transfer belt, the photoconductor, the squeeze roller, the binding roller, and the like.

[0004]

However, when a foreign substance is caught between each member such as a developing roller and a photoreceptor and each scraping member, the surface of the member cannot be partially cleaned, and the toner is removed. There is a problem that it is chronically attached to a part of the member surface.

When the above-mentioned problem occurs on the developing roller, a streak-like abnormality corresponding to a foreign matter is caused due to, for example, the chronically adhered toner directly adhering to the photoreceptor or the developing bias not operating normally. There is a problem that toner adheres to a transferred image.

When the above-mentioned problem occurs on the photosensitive member, abnormal toner is transferred to the transfer material to form an abnormal image, and when the defect occurs on the squeeze roller, the amount of carrier adhered on the photosensitive member is abnormally large. If the transfer roller collapses or the transfer material becomes abnormally wet, and if it occurs on the binding roller, abnormal toner adheres to the photoreceptor and causes abnormal images such as streaks on the transfer image. When a belt is used, if the transfer material is stained on the back, or if multiple photoconductors are used during color image formation, the toner of the color that has not been cleaned will adhere to the photoconductor of another color and develop. There is a problem of causing color mixing of the liquid.

[0007] The present invention solves the above problems, and even when foreign matter is caught between each member and each scraping member,
It is an object of the present invention to provide a method of removing a developer in a wet image forming apparatus capable of obtaining a good image.

[0008]

According to the first aspect of the present invention,
The latent image on the latent image carrier is developed with a developing solution composed of a carrier liquid and toner particles, and after removing the excess developing solution supplied on the latent image carrier, the latent image on the latent image carrier is removed. In a method of removing a developer of a wet image forming apparatus for electrostatically binding a toner image and transferring the toner image to a transfer material, the method of scraping the developer onto a moving surface of each member contacted with the developer The scraping member is brought into contact with at least one of the scraping members in a generatrix direction of the moving surface orthogonal to the moving direction of the moving surface.

According to a second aspect of the present invention, in the method for removing a developer of a wet image forming apparatus according to the first aspect, a member contacting the developer is the latent image carrier.

According to a third aspect of the present invention, in the method for removing a developer of the wet image forming apparatus according to the first aspect, the member in contact with the developer supplies the developer to the latent image carrier. It is a developing roller.

According to a fourth aspect of the present invention, in the method for removing a developer of the wet image forming apparatus according to the first aspect of the present invention, the member contacted with the developer further comprises an excess of the excess liquid supplied to the latent image carrier. It is a squeeze roller for removing the developer.

According to a fifth aspect of the present invention, in the method for removing a developer of the wet image forming apparatus according to the first aspect of the present invention, further, the member in contact with the developer transfers the toner image on the latent image carrier. It is a binding roller for electrically binding.

According to a sixth aspect of the present invention, in the method for removing a developer of the wet image forming apparatus according to the first aspect, the member in contact with the developer transports a transfer material onto which the toner image is transferred. It is a transfer belt.

According to a seventh aspect of the present invention, there is provided the method of removing a developer for a wet image forming apparatus according to any one of the first to sixth aspects, further comprising a longitudinal end of the scraping member. The scraping member is caused to reciprocate by an eccentric cam contacting the eccentric cam and a spring for bringing the scraping member into contact with the eccentric cam.

According to an eighth aspect of the present invention, in the method for removing a developer of a wet image forming apparatus according to any one of the first to sixth aspects, the scraping member is further reciprocated by a crank mechanism. It is characterized by moving.

According to a ninth aspect of the present invention, in the method for removing a developer of a wet image forming apparatus according to any one of the first to sixth aspects, the scraping member is further provided with a rack and pinion mechanism. It is characterized by reciprocating.

According to a tenth aspect of the present invention, in the method for removing a developer of a wet image forming apparatus according to any one of the first to sixth aspects, the scraping member is further pushed in the longitudinal direction. The scraper is reciprocated by a hydraulic pump and a return spring.

According to an eleventh aspect of the present invention, in the method for removing a developer of a wet image forming apparatus according to any one of the first to sixth aspects, the solenoid further includes a solenoid for pushing the scraping member. The scraping member is reciprocated by a spring.

[0019]

FIG. 1 shows an image forming apparatus employing an embodiment of the present invention.
A charger 2, an exposure device 3, an eraser 4, a developing device 5, a transfer device 6, a cleaning device 7, a static eliminator 8, and the like are disposed around the device.

The developing device 5 supplies a developing solution in which toner particles are dispersed in a carrier liquid to form a toner image on the peripheral surface of the photosensitive drum 1 and a developing roller 9 necessary for transfer. A squeeze roller 10 for removing excess developer from the peripheral surface of the photoconductor drum 1 while leaving; and a binding roller 11 for electrostatically bonding a toner image on the peripheral surface of the photoconductor 1
And a container 12 for accommodating these members.

A bias voltage is applied to the developing roller 9 by bias applying means (not shown), and the developing roller 9 is rotationally driven by a driving means (not shown) in a direction indicated by an arrow b which is opposite to the direction in which the photosensitive drum 1 rotates in the direction indicated by the arrow a. Above the developing roller 9, a developing solution supply unit 13 that supplies a developing solution to the developing roller 9 is arranged. In the vicinity of the developing roller 9, a scraper 9 a as a scraping member is disposed with one end of the scraper 9 a in contact with the peripheral surface of the developing roller 9.
The developing solution supplied from the developing solution supply means 13 accumulates in a wedge-shaped space 14 formed by the developing roller 9 and the scraper 9 a, and the rotation of the developing roller 9 causes the photosensitive drum 1 and the developing roller 9 to face each other. Supplied to

The scraper 9 a has a function of forming the wedge-shaped space 14 and removing excess developer from the surface of the developing roller 9. As shown in FIG. 2, the scraper 9a is provided on a scraper supporting member 15 having the other end fixed to the container 12 in a generatrix direction of the surface orthogonal to the moving direction of the peripheral surface of the developing roller 9, that is, the developing roller 9 Are supported movably in the direction of arrow A in FIG. An eccentric cam 16 that is rotationally driven by a driving unit (not shown) is in contact with one end of the scraper 9a, and the other end is attached with the other end of a compression spring 17 having one end fixed to a side plate (not shown) of the container 12. Have been. With this configuration, the scraper 9 a is reciprocated in the direction of arrow A in FIG. 2 with the rotation of the eccentric cam 16 while one end of the scraper 9 a is in contact with the peripheral surface of the developing roller 9. The operation of a driving unit (not shown) for rotating and driving the eccentric cam 16 is controlled by a control unit (not shown) provided in the main body of the wet image forming apparatus so that the eccentric cam 16 makes one rotation when the developing roller 9 makes one rotation. .

At a position downstream of the position of the developing roller 9 in the rotation direction of the photosensitive drum 1, the driving speed of the photosensitive drum 1 is approximately three times as high as the linear speed of the photosensitive drum 1 by driving means (not shown). A squeeze roller 10 that is driven to rotate in the same direction of arrow c is provided. Squeeze roller 10
, A scraper 10 a as a scraping member is arranged with one end thereof in contact with the peripheral surface of the squeeze roller 9. The other end side of the scraper 10a is the container 1
2 and removes excess developer adhered on the peripheral surface of the squeeze roller 10 and removed from the peripheral surface of the photosensitive drum 1.

A binding roller 11 is disposed downstream of the squeeze roller 10 in the rotational direction of the photosensitive drum 1 with a gap of about 50 μm between the peripheral surface and the peripheral surface of the photosensitive drum 1. Have been. A high voltage power supply 18 is connected to the binding roller 11, and has a polarity such that the toner image is bound to the photosensitive drum 1, and the photosensitive drum 1 is disposed between the binding roller 11 and the photosensitive drum 1. A voltage necessary for flowing a current of about 1 μA / cm or more per one axial length is applied. In the vicinity of the binding roller 11, a scraper 11 a as a scraping member is disposed with one end of the scraper 11 a in contact with the peripheral surface of the binding roller 11. The other end of the scraper 11 a is attached to the container 12, and removes the developer attached to the peripheral surface of the binding roller 11. Note that the binding roller 11 may be disposed with its peripheral surface in contact with the peripheral surface of the photosensitive drum 1.

The photosensitive drum 1 is moved from the position where the developing device 5 is disposed.
A transfer device 6 is disposed on the downstream side in the rotation direction.
The transfer device 6 includes a driving roller 19, a driven roller 20,
It has a transfer belt 21, a transfer charger 22, and the like.

The transfer device 6 rotates the drive roller 19 by a drive unit (not shown), and transfers the transfer belt 21 wound around the drive roller 19 and the driven roller 20.
Is moved in the direction of arrow d, which is the same direction as the rotation direction of the photoconductor drum 1, at the same speed as the linear speed of the photoconductor drum 1, and the transfer paper as a transfer material fed from a paper feeding device (not shown) P is conveyed, and the toner image on the peripheral surface of the photosensitive drum 1 is transferred onto the transfer paper P by the transfer charger 22.

The driven roller 20 via the transfer belt 21
A web 23 as a scraping member is provided at a position facing the web. Both ends of the web 23 made of felt, paper, toweling, and the like are connected to the winding members 24, 24, and the center of the web 23 is pressed against the transfer belt 21 by the pressing roller 25 at a predetermined pressure. The web 23 absorbs or absorbs the developer adhering to the transfer belt 21 at the pressure contact portion by the pressure contact roller 25, and when the adsorption surface or the absorption surface becomes dirty, the winding members 24, 24.
Is actuated and wound, and a new surface is pressed against the transfer belt 21.

The photosensitive drum 1 is moved from the position where the transfer device 6 is disposed.
The cleaning device 7 is disposed on the downstream side in the rotation direction. The cleaning device 7 has a cleaning roller 26, a scraper 27 as a scraping member, and the like.

A cleaning roller 26, which is made of a sponge or the like and is rotatably provided, mainly removes the carrier liquid on the photosensitive drum 1 and has one end attached to a side plate (not shown) of the cleaning device 7 and the other end exposed to light. The scraper 27 in contact with the peripheral surface of the body drum 1 mainly removes toner on the photosensitive drum 1.

The operation of the above-described image forming apparatus will be described below. First, the photosensitive drum 1 is neutralized by the neutralizer 8, averaged to a reference potential, and uniformly charged by the charger 2. Next, exposure is performed by the exposure device 3 to form an electrostatic latent image on the photosensitive drum 1, and unnecessary charges are erased by the eraser 4. Next, a developing solution is supplied from the developing roller 9 to the photosensitive drum 1, and the electrostatic latent image becomes a toner image. At this time, a driving unit (not shown) for rotating and driving the eccentric cam 16 with the rotation of the developing roller 9 operates, and the scraper 9a reciprocates. After that, the excess developer on the photosensitive drum 1 is removed by the squeeze roller 10, and the toner is bound to the photosensitive drum 1 by the binding roller 11.

Paper P fed from a paper feeding device (not shown)
Is transferred by the transfer belt 6, and the toner image on the photosensitive drum 1 is transferred to the sheet P by the transfer charger 22.

On the other hand, the developer remaining on the photosensitive drum 1 is removed by the cleaning roller 26 and the scraper 27. Thereafter, the residual charge on the photosensitive drum 1 is eliminated by the neutralization light, the photosensitive drum 1 is brought into an initial state without a developing solution, and the process shifts to the next image forming step again.

During the above-described operation, the scraper 9a is reciprocated with the rotation of the developing roller 9, so that the developer applied to the developing roller 9 by the bias application can be reliably removed. It is possible to prevent the occurrence of problems such as background contamination due to a reduction in the developing bias and unnecessary toner adhered to an image, which are caused by the presence of the developer remaining after being removed.

In the above embodiment, as an example of the reciprocating movement of the scraping member, the scraper 9 is rotated with the rotation of the developing roller 9.
a, but instead of this, at least one of the scraper 10a, the scraper 11a, the web 23, and the scraper 27 is configured to be able to reciprocate similarly to the scraper 9a, and the squeeze roller 10, A configuration of reciprocating with the rotation or movement of the binding roller 11, the transfer belt 21, or the photosensitive drum 1 may be adopted. In addition, the web 23 is unitized with each of the winding members 24, 24 and the pressing roller 25, and is configured to be able to reciprocate with each unit.

By adopting the above configuration, when the scraper 10a is reciprocally movable, the developer on the squeeze roller 10 can be reliably removed.
The amount of the developing solution on the photosensitive drum 1 removed by the squeeze roller 10 increases, and an unnecessary developing solution remains on the photosensitive drum 1. Of the carrier liquid can be prevented. In particular, by preventing the carrier liquid from adhering to the sheet P, the sheet P can be easily dried at the time of fixing, and unnecessary energy consumption can be prevented.

When the scraper 11a is reciprocally movable, the developer on the binding roller 11 can be surely removed, so that the carrier liquid adhering to the binding roller 11 is transferred to the photosensitive drum 1. It is possible to prevent problems such as occurrence of transfer fogging caused by the supply and occurrence of background contamination caused by the toner adhering to the binding roller 11 adhering to the photosensitive drum 1.

When the web 23 is reciprocally movable, the developer on the transfer belt 21 can be reliably removed, so that unnecessary toner adheres to the paper P and color mixing during color image formation. Can be prevented.

When the scraper 27 is reciprocally movable, toner after transfer on the photosensitive drum 1 can be surely removed. Therefore, re-development due to incomplete removal of the residual potential after transfer is possible. And the occurrence of image disturbance due to toner re-transfer can be prevented.

In the above embodiment, the eccentric cam 16 and the compression spring 17 are used to scrape the scraper 9a.
3. Instead of this, as shown in FIG. 3, a disk 28 having a support shaft 28a as a center of rotation, and one end connected to the peripheral portion of the disk 28 and the other end connected to one end of the scraper 9a, as shown in FIG. The disc 28 may be driven to rotate and the scraper 9a may reciprocate by using a crank mechanism including a link 29 rotatably supported on each of the scrapers 9a.

Further, a rack-and-pinion mechanism comprising a pinion 30 rotated by a forward / reverse rotation motor (not shown) as shown in FIG. 4 and a rack 31 integrally fixed to the scraper 9a, as shown in FIG. A configuration using a hydraulic cylinder 32 connected to a hydraulic pump (not shown) and a compression spring 33 as a return spring, or a configuration using a solenoid 34 and a compression spring 35 as a return spring as shown in FIG. 9a may be reciprocated.

[0041]

According to the first aspect of the present invention, of the scraping member for scraping the developer in the generatrix direction of the moving surface orthogonal to the moving direction of the moving surface of the member with which the developer contacts. By reciprocating at least one, even if a foreign substance is interposed between the member that comes into contact with the developer and the scraping member, the foreign substance is prevented from staying in one place,
The occurrence of abnormal images such as streaks can be prevented.

According to the second aspect of the present invention, the scraping member for scraping the developing solution on the surface of the latent image carrier is reciprocated in the generatrix direction of the surface of the latent image carrier, so that the surface of the latent image carrier is reciprocated. It is possible to reliably remove the toner and the like after the transfer, and it is possible to prevent the occurrence of the re-development due to the incomplete removal of the residual potential after the transfer and the disturbance of the image due to the toner re-transfer.

According to the third aspect of the present invention, the scraping member for scraping the developer on the surface of the developing roller is reciprocated in the generatrix direction on the surface of the developing roller, so that the developer applied to the developing roller by the bias application. Can be reliably removed, and the occurrence of problems such as soiling due to a decrease in development bias or unnecessary toner adhering to an image due to the presence of the developer remaining after being removed from the developing roller is prevented. be able to.

According to the fourth aspect of the present invention, the developing solution on the squeeze roller is reliably removed by reciprocating the scraping member for scraping the developer on the squeeze roller surface in the generatrix direction of the squeeze roller surface. Can be
The amount of the developer on the latent image carrier removed by the squeeze roller increases, and unnecessary developer remains on the latent image carrier. The carrier liquid can be prevented from adhering. In particular, by preventing the carrier liquid from adhering to the transfer material, the transfer material can be easily dried at the time of fixing, and unnecessary energy consumption can be prevented.

According to the fifth aspect of the present invention, the developing solution on the binding roller is reciprocated in the generatrix direction of the binding roller surface by scraping the developer on the binding roller surface. The carrier liquid adhered to the binding roller can be reliably removed, and transfer fogging caused by the supply of the carrier liquid to the latent image carrier, and the toner adhered to the binding roller adheres to the latent image carrier. Therefore, it is possible to prevent problems such as the occurrence of background dirt.

According to the sixth aspect of the invention, the developer on the transfer belt is reliably removed by reciprocating the scraping member for scraping the developer on the surface of the transfer belt in the generatrix direction of the surface of the transfer belt. Thus, it is possible to prevent unnecessary toner from adhering to the transfer material and occurrence of color mixing during color image formation.

[0047] Claims 7, 8, 9, and 1
According to the invention described in claim 11, even if a foreign substance is caught between the member with which the developer contacts and the scraping member, the foreign substance is prevented from staying in one place, and a streak or the like is prevented. The occurrence of an abnormal image can be prevented.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a main part of an image forming unit of an image forming apparatus employing an embodiment of the present invention.

FIG. 2 is a perspective view illustrating a reciprocating mechanism of a scraping member used in one embodiment of the present invention.

FIG. 3 is a diagram illustrating a reciprocating mechanism of a scraping member used in a modification of the embodiment of the present invention.

FIG. 4 is a diagram illustrating a reciprocating mechanism of a scraping member used in another modification of the embodiment of the present invention.

FIG. 5 is a diagram illustrating a reciprocating mechanism of a scraping member used in another modification of the embodiment of the present invention.

FIG. 6 is a diagram illustrating a reciprocating mechanism of a scraping member used in another modification of the embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 1 latent image carrier (photosensitive drum) 9 developing roller 9a scraping member (scraper) 10 squeeze roller 10a scraping member (scraper) 11 binding roller 11a scraping member (scraper) 16 eccentric cam 17 spring (compression spring) Reference Signs List 21 transfer belt 23 scraping member (web) 27 scraping member (scraper) 28 disc 29 link 30 pinion 31 rack 32 hydraulic pump (hydraulic cylinder) 33 return spring (compression spring) 34 solenoid 35 return spring (compression spring)

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Takeo Tsukamoto 1-3-6 Nakamagome, Ota-ku, Tokyo, Ricoh Co., Ltd.

Claims (11)

[Claims] 1. A latent image on a latent image carrier is developed with a developer comprising a carrier liquid and toner particles, and after removing the excess developer supplied on the latent image carrier, the latent image is removed. In a method of removing a developer of a wet image forming apparatus for electrostatically binding a toner image on an image carrier and transferring the toner image to a transfer material, the developing device may be configured such that the developing solution is applied to a moving surface of each member contacted with the developing solution. A wet type wherein each of the scraping members for scraping the liquid is brought into contact with each other, and at least one of the scraping members is reciprocated in a generatrix direction of the moving surface orthogonal to the moving direction of the moving surface. A method for removing a developer in an image forming apparatus. 2. A method according to claim 1, wherein said member in contact with said developer is said latent image carrier. 3. The method according to claim 1, wherein the member that contacts the developing solution is a developing roller that supplies the developing solution to the latent image carrier. 4. A wet image forming apparatus according to claim 1, wherein said member in contact with said developer is a squeeze roller for removing excess developer supplied to said latent image carrier. Developer removal method. 5. A wet image forming apparatus according to claim 1, wherein said member in contact with said developer is a binding roller for electrostatically binding said toner image on said latent image carrier. A method for removing the developer from the apparatus. 6. A method according to claim 1, wherein said member in contact with said developer is a transfer belt for conveying a transfer material onto which said toner image is transferred. 7. The scraping member is reciprocated by an eccentric cam contacting one end in the longitudinal direction of the scraping member and a spring contacting the scraping member with the eccentric cam. A method for removing a developer from a wet image forming apparatus according to claim 1. 8. The method according to claim 1, wherein said scraping member is reciprocated by a crank mechanism. 9. The method according to claim 1, wherein said scraping member is reciprocated by a rack and pinion mechanism. 10. The scraping member according to claim 1, wherein the scraping member is reciprocated by a hydraulic pump for pushing the scraping member in a longitudinal direction and a return spring. Developer removing method for a wet image forming apparatus. 11. The wet image forming apparatus according to claim 1, wherein said scraping member is reciprocated by a solenoid for pushing said scraping member and a return spring. A method for removing the developer from the apparatus.