JP2002062740A - Cleaning device, and wet image forming apparatus equipped therewith - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely remove developer remaining on the surface of a transfer body, after transferring an image to transfer material by a cleaning blade, without causing cost rise in a wet image forming apparatus. SOLUTION: As for the transfer body 10, a soft rubber elastic layer is provided by attaching soft urethane rubber, whose rubber hardness is about 50 to base material made of synthetic resin, and a toner releasing layer is formed by coating the soft rubber elastic layer with 30 to 50 μm nonadhesive resin coating film. Meanwhile, the cleaning blade 34 is an elastic blade made of urethane rubber whose hardness is set higher than the surface of the transfer body 10, about 70 to 80. Then, the wet developer, remaining on the transfer body 10 after transferring the image to the transfer material, is removed by pressing the blade 34 against the surface of the transfer body 10, by a pressing force in the range of 50 gf to 250 gf per cm length.

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 copier, a facsimile, a printer, or a multifunction machine for transferring an image onto a transfer material such as paper or an OHP film and then developing the image on a transfer member. The present invention relates to a cleaning device for removing an agent with a cleaning blade. and,
The present invention relates to an image forming apparatus provided with such a cleaning device, and particularly to a wet image forming apparatus using a wet developer.

[0002]

2. Description of the Related Art In a color image forming apparatus, for example, a dedicated image carrier is provided for each color, a single-color image is individually formed on these image carriers, and the single-color images are transferred to each other. There is a type in which a composite color image is formed on a transfer member, and the resultant is collectively transferred to record a color image on a transfer material. A cleaning blade of a cleaning device is pressed against the transfer member, and after the image is transferred to the transfer material, the developer remaining on the transfer member is removed by the cleaning blade.

Incidentally, this type of color image forming apparatus includes a dry type using a dry developer and a wet type using a wet developer.

A wet developer has a toner particle size of 2 μm or less, which is smaller than a dry developer. For this reason, when the transfer material is a coated paper or the like having a smooth surface, the toner after transfer is well embedded and the image quality can be improved. However, in the case of plain paper generally used in offices, since the paper surface is rough, toner adhesion is poor, and the image quality is not good.

Therefore, in the case of a wet image forming apparatus,
Conventionally, soft rubber has been used for a transfer body, and transfer to a transfer material has been performed at high pressure.

[0006]

However, in such a conventional wet image forming apparatus, the toner particle size is small, the adhesiveness is high, and the surface roughness of the transfer member using a soft rubber is large. After the image is transferred to the transfer material, there has been a problem that it is difficult to reliably remove the wet developer remaining on the transfer body by a cleaning blade of a cleaning device.

Further, in a transfer body using soft rubber, since the coefficient of friction is large, self-excited vibration (chattering vibration) occurs, the cleaning blade comes into contact with and separates from the cleaning blade, and the toner passes through the cleaning blade. There was a problem that the developer remaining on the transfer member could not be removed with a cleaning blade.

Therefore, some conventional image forming apparatuses use a cleaning device that uses an electric field roller to which a voltage having a polarity opposite to that of toner is applied to a cleaning blade. However, in such a cleaning device, the cost is increased, and the toner is not sufficiently removed.

Therefore, a first object of the present invention is to provide a wet type image forming apparatus in which the developer remaining on the surface of a transfer body after image transfer can be reliably removed by a cleaning blade without increasing costs. It is to make.

A second object is to provide a margin for the arrangement of a plurality of image carriers to facilitate design.

A third object is to make it possible to manufacture a cleaning blade harder than the surface of the transfer member at low cost and easily.

A fourth object of the present invention is to eliminate the possibility of chattering of the cleaning blade due to friction with the transfer member.

A fifth object is to make it possible to easily and inexpensively manufacture a lubricant applying means for applying a lubricant to a transfer body.

[0014] The sixth problem is that without increasing the cost,
It is an object of the present invention to provide a wet image forming apparatus capable of reliably removing a developer remaining on the surface of a transfer member after image transfer by a cleaning blade.

[0015]

In order to achieve the first object, the invention according to claim 1 removes a developer remaining on a transfer body after transferring an image to a transfer material by a cleaning blade. In a cleaning device of a wet image forming apparatus, a soft rubber elastic layer and a toner release layer are provided on the surface of a transfer body, while a cleaning blade is made of a material harder than the surface of the transfer body. Length 1
It is characterized by being pressed with a pressing force in the range of 50 gf to 250 gf per cm.

According to a second aspect of the present invention, in order to achieve the second object, in the cleaning device for a wet image forming apparatus according to the first aspect, the transfer member is an endless belt.

According to a third aspect of the present invention, there is provided a cleaning apparatus for a wet image forming apparatus according to the first or second aspect, wherein the cleaning blade is an elastic blade made of urethane rubber. It is characterized by the following.

According to a fourth aspect of the present invention, there is provided a cleaning apparatus for a wet-type image forming apparatus according to the first, second or third aspect of the present invention, wherein the cleaning element is located upstream of the cleaning blade in the rotation direction of the transfer member. A lubricant applying means for applying a lubricant to the transfer body is provided at the position.

According to a fifth aspect of the present invention, in order to achieve the fifth object, in the cleaning apparatus for a wet image forming apparatus according to the fourth aspect, the lubricant applying means is made of a soft sponge. And

According to a sixth aspect of the present invention, in order to achieve the sixth object, a wet image forming apparatus is provided with the cleaning device according to the first aspect.

[0021]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a schematic configuration of a main part of a color wet image forming apparatus. Reference numeral 10 in the figure
Is a transfer member, which may be in the form of a drum, but in this example is in the form of a wide endless belt.

The transfer member 10 is, for example, as shown in FIG.
A soft rubber elastic layer 12 is provided on a synthetic resin base material 11 by bonding soft urethane rubber or the like having a rubber hardness of about 50, and a non-adhesive resin film of 30 to 50 μm is coated thereon. Thus, the toner release layer 13 is formed. Then, a multilayer structure having a predetermined electrical characteristic with a total thickness of about 0.6 mm is formed.

The toner release layer 13 on the surface is particularly important,
In addition to smoothness, wear resistance, chemical resistance, low friction, etc. are required. In order to facilitate cleaning, the surface roughness is preferably set to Rz 1 μm or less.

As shown in FIG. 1, the transfer body 10 is wound around a driving roller 15, a tension roller 16, and a support roller 17, and is urged by a tension spring 18 to stretch the tension roller 16. . These rollers 15, 16 and 17 are bridged between a pair of side plates (not shown) provided facing each other in the image forming apparatus main body, and are rotatably supported via bearings.

In the illustrated color wet image forming apparatus, the cyan, magenta, yellow, and black electrophotographic image forming apparatuses 20 are arranged for each color along the transfer member 10 between the driving roller 15 and the supporting roller 17. Provide side by side. In FIG.
Only one electrophotographic image forming apparatus 20 is shown, and the other three electrophotographic image forming apparatuses are not shown.

The electrophotographic image forming apparatus 20 for each color may be in the form of a belt in contact with the transfer member 10 individually. In this example, a drum-shaped photosensitive member 22 is provided. The photoreceptor 22 is provided with a charging device 23, a writing device (not shown), a wet developing device 24, a transfer device (not shown), a cleaning device 25, and the like.

The wet developing device 24 contains a wet developer in a developing case 26. The wet developer contains a toner in a liquid carrier. Then, the developing roller 28 is replenished by the replenishing roller 27, and is adhered by the developing sleeve 28 to develop the electrostatic latent image on the photoconductor 22.

In FIG. 1, reference numeral 30 denotes a transfer roller which comes into contact with the drive roller 15 via the transfer member 10;
The color image on the transfer body 10 is transferred to the transfer material P which has been transported during the transfer.

Reference numeral 32 in FIG. 1 denotes a cleaning device for removing the wet developer remaining on the transfer body 10 after transferring the image to the transfer material P. The cleaning device 32 includes:
A lubricant application roller 33 and a cleaning blade 34 as a lubricant application unit are provided. The lubricant application roller 33 is provided at a position upstream of the cleaning blade 34 in the rotation direction of the transfer body 10.

The lubricant application roller 33 is made of a soft sponge such as urethane foam, and is supported by the support roller 1 via the transfer member 10.
7 and rotates at a relatively high speed in a direction opposite to the transfer body 10 (reverse direction), and when there is residual developer adhered or electrostatically adhered to the transfer body 10, it is adsorbed. When the transfer member 10 is in a dry state, the liquid carrier or toner adsorbed thereon is applied.

The cleaning blade 34 is an urethane rubber elastic blade having a hardness higher than that of the surface of the transfer body 10 and a rubber hardness of about 70 to 80, and the base side is connected to the metal holder 35 as shown in FIG. Adhere and fix. The holder 35 is reinforced by a reinforcing plate 36 and one end of a tension spring 37 is hung on the reinforcing plate 36.

The tension of the cleaning blade 34 is applied to the surface of the transfer body 10 by applying a biasing force by a tension spring 37 to the rotating shaft about the support shaft 38, and a pressing force of 20 gf / cm in the case of a dry type. Pressing is performed with a pressing force in the range of 50 to 250 gf / cm, which is larger than that of.

When the pressing force of the cleaning blade 34 exceeds 100 gf / cm, the pressing force may cause an indentation on the transfer member 10. Therefore, it is preferable to release the pressing when the machine is stopped.

Now, when this color wet image forming apparatus is driven, the drive roller 15 is rotated in the direction of the arrow, and the transfer body 10 is rotated counterclockwise while the tension roller 16 and the support roller 17 are driven to rotate. . at the same time,
The photosensitive member 22 of each electrophotographic image forming apparatus 20 is rotated clockwise.

As the photosensitive member 22 rotates, the charging device 23
Then, the surface is uniformly charged, and writing is performed by irradiating writing light L with a writing device (not shown) to form an electrostatic latent image on the photoreceptor 22. Thereafter, the wet developing device 24 applies a wet developer to visualize the electrostatic latent image, and each electrophotographic image forming device 20 forms a single-color image individually.

Then, with the rotation of the transfer member 10, the monochromatic images on the respective photosensitive members 22 are synchronously transferred by the respective transfer devices to form a composite color image on the transfer member 10. The color image is collectively transferred by the transfer roller 30 and is recorded on the transfer material P conveyed between the transfer member 10 and the color image.

The transfer material P after image recording is conveyed to a fixing device (not shown) as it is, for example, by applying heat and pressure to fix the transferred image, and then discharged to a discharge stack (not shown). I do.

On the other hand, in the transfer body 10 after the image transfer, the residual developer is sucked and removed by the lubricant application roller 33 of the cleaning device 32. Thereafter, the cleaning device 32
The developer remaining on the transfer body 10 is scraped off by the cleaning blade 34 described above.

In the illustrated example, the soft rubber elastic layer 12 and the toner release layer 13 are provided on the surface of the transfer member 10, while the cleaning blade 34 is made of a material harder than the surface of the transfer member 10. Length on the surface of the transfer body 10
Pressing is performed with a pressing force in the range of 50 gf to 250 gf per cm.

Therefore, as shown in FIG. 4, the edge 34a of the cleaning blade 34 can be strongly damped so as to dig into the transfer member 10 to excavate the residual developer, and the wet image forming apparatus can soften the edge of the transfer member. Even when rubber is used, the developer remaining on the transfer body 10 after the image transfer can be reliably removed by the cleaning blade 34. Since the configuration is simple, the cost does not increase.

Normally, when a rubber cleaning blade 34 is pressed against the rubber transfer member 10 to rotate and transport the transfer member 10, a strong frictional force acts between the transfer member 10 and the stick-slip phenomenon (chatter) occurs, and the cleaning blade 34
Will not function properly.

However, in the illustrated color wet type image forming apparatus, the cleaning blade 3 is rotated in the rotation direction of the transfer body 10.
A lubricant application roller 33 is provided at an upstream position of
In addition to adsorbing and removing the residual developer on the transfer member
When the surface is in a dry state, the liquid carrier or toner adsorbed on the surface is applied, so that there is no danger that the cleaning blade 34 may chatter due to chattering and the cleaning blade 34 may not function normally.

In the illustrated color wet image forming apparatus, the adsorbed liquid carrier or toner is reapplied as a lubricant by the lubricant applying roller 33, but the lubricant or the liquid carrier is applied to the lubricant applying roller 33 in advance. Alternatively, they may be applied to an unused transfer body 10.

In the illustrated example described above, the case where the present invention is applied to a color wet image forming apparatus has been described. However, the present invention is not limited to color, but may be a two-color wet image forming apparatus. The present invention can be similarly applied to an image forming apparatus of a type in which an image formed on a body is once transferred to a transfer body and then transferred to a transfer material.

[0045]

As described above, according to the first aspect of the present invention, while the soft rubber elastic layer and the toner release layer are provided on the surface of the transfer body, the cleaning blade is harder than the surface of the transfer body. The transfer member is pressed against the surface of the transfer member with a pressing force in the range of 50 gf to 250 gf per 1 cm length.

Therefore, the edge of the cleaning blade can be bitten into the transfer member and can be strongly damped to excavate the residual developer. Even when a soft rubber is used for the transfer member in a wet image forming apparatus, the transfer after image transfer is performed. The developer remaining on the body can be reliably removed by the cleaning blade. Since the configuration is simple, the cost does not increase.

According to the second aspect of the present invention, since the transfer body is an endless belt, it is possible to provide a margin for the arrangement of the plurality of image carriers and to facilitate the design.

According to the third aspect of the present invention, since the cleaning blade is an elastic blade made of urethane rubber, a cleaning blade harder than the surface of the transfer body can be manufactured at low cost and easily.

According to the fourth aspect of the present invention, since the lubricant applying means is provided at a position upstream of the cleaning blade in the rotation direction of the transfer body, the lubricant is applied to the transfer body by the lubricant applying means, and the lubricant is applied. Even if the cleaning blade made of rubber is pressed against the transfer member with a relatively large force, it is possible to eliminate the possibility that the cleaning blade will not function properly due to chatter.

According to the fifth aspect of the present invention, since the lubricant applying means is made of a soft sponge, the lubricant applying means for applying the lubricant to the transfer body can be manufactured inexpensively and easily.

According to the sixth aspect of the present invention, since the cleaning device according to the first aspect is provided, the developer remaining on the transfer body after the image transfer is reliably removed by the cleaning blade without increasing the cost. It is possible to provide a wet image forming apparatus that can be used.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a main part of a color wet image forming apparatus according to the present invention.

FIG. 2 is an explanatory diagram of a configuration of a transfer body used in the image forming apparatus.

FIG. 3 is a partially enlarged view of a cleaning device used in the image forming apparatus.

FIG. 4 is a partially enlarged view of the cleaning device.

[Explanation of symbols]

 REFERENCE SIGNS LIST 10 transfer member 11 base material 12 soft rubber elastic layer 13 toner release layer 20 electrophotographic image forming device 22 photoreceptor (image carrier) 24 wet developing device 32 cleaning device 33 lubricant applying roller (lubricant applying means) 34 cleaning Blade P transfer material

Claims (6)

[Claims] 1. A cleaning device of a wet image forming apparatus for removing a developer remaining on a transfer member after transferring an image to a transfer material by a cleaning blade, wherein a soft rubber elastic layer and a toner release are formed on the surface of the transfer member. While providing the layer, the cleaning blade is made of a material harder than the surface of the transfer body, and a length is formed on the surface of the transfer body.
A cleaning device for a wet image forming apparatus, which is pressed with a pressing force in a range of 50 gf to 250 gf per cm. 2. The cleaning device according to claim 1, wherein the transfer member is an endless belt. 3. The cleaning device for a wet image forming apparatus according to claim 1, wherein said cleaning blade is an elastic blade made of urethane rubber. 4. A lubricant applying means for applying a lubricant to the transfer body at a position upstream of the cleaning blade in a rotation direction of the transfer body.
3. The cleaning device for a wet image forming apparatus according to claim 1. 5. The cleaning device for a wet image forming apparatus according to claim 4, wherein said lubricant applying means is made of a soft sponge. 6. A wet image forming apparatus comprising the cleaning device according to claim 1.