KR20000052073A - Liquid electrophotographic printer - Google Patents

Abstract

PURPOSE: A method for cleaning a wet electro photographic printer is provided to remove a residual developing solution between a developing roller and a squeeze roller by transmitting the solution to a photosensitive belt without backward rotation of the squeeze roller, thereby preventing damage of the photosensitive belt due to friction caused by the backward rotation and minimizing the printer and the developing unit by omitting a squeeze blade. CONSTITUTION: A method for cleaning a wet electro photographic printer includes the steps of transmitting residual developing solution between a developing roller and a squeeze roller to a surface of a photosensitive belt(533), squeezing the residual developing solution by passing the squeeze roller for adhering a part of toner and liquid carrier mixed in the residual developing solution on the surface of the photosensitive belt(535), and removing the residual developing solution adhered on the photosensitive belt to a surface of a cleaning roller due to a surface energy of the residual developing solution(537).

Description

Cleaning method of wet electrophotographic printing machine {Liquid electrophotographic printer}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cleaning method of a wet electrophotographic printing press, and more particularly, to a wet electrophotographic printing press which transfers and removes the developer remaining on the photosensitive belt from the developing roller to the squeeze roller after the developing operation. It relates to a cleaning method of the.

In general, an electrophotographic printing machine such as a laser printer uses a photosensitive medium capable of forming an electrostatic latent image such as a photosensitive drum or a photosensitive belt. After the electrostatic latent image is formed on the photosensitive medium, the electrostatic latent image is developed with a toner or developer having a predetermined color, and then transferred onto a recording paper to obtain a desired image.

The electrophotographic printing presses are largely classified into wet and dry according to the toner used. In the wet type, a developer in which a toner is mixed in a volatile liquid carrier is used. The wet electrophotographic printing machine using such a developing solution has better print quality than the dry type using the powder toner, and can prevent damage caused by harmful toner dust, and its use is increasing.

1 is a schematic diagram illustrating a general wet electrophotographic printer.

Referring to FIG. 1, a photosensitive belt 10, which is a photosensitive medium, is supported in a caterpillar state by a plurality of guide rollers 11. The photosensitive belt 10 is driven in an endless track while its surface is charged at a potential of approximately 600V by the charger 12.

Subsequently, the charged surface is changed to a predetermined potential (about 250V) by the light scanned by the laser scanning unit 13 provided adjacent to each developer 20, thereby forming an electrostatic latent image.

When the developer charged by the predetermined injection means (not shown) is injected into the developing gap between the developing roller 22 and the photosensitive belt 10, the injected developer is maintained at a potential of approximately 450V. It is transferred to and attached to the electrostatic latent image region having a lower potential than the developing roller 22.

In this way, the developer attached to the electrostatic latent image region by the potential difference is squeezed by the squeeze roller 24 so that the toner is filmed in the developer to form a toner image, and most of the carriers other than the filmed toner are photosensitive belts ( 10) is squeezed from and removed. Here, the toner image is dried by the drying means 15 and then transferred to the transfer roller 16 by the difference in surface energy. Then, the toner image transferred to the transfer roller 16 is finally printed on the printing paper P passed between the transfer roller 16 and the fixing roller 17.

FIG. 2 is a schematic diagram illustrating a drip line removal operation remaining on the photosensitive belt of FIG. 1.

Referring to FIG. 2, at the end of the development mode as described above, after the pressurization applied to the developing roller 22 is released, that is, the developing roller 22 is moved downward a predetermined distance, the developing roller 22 and the squeeze roller The so-called drip-line D, which is a residual developer stagnant in the photosensitive belt 10 between 24, is removed. That is, when the squeeze roller 24 is rotated in a state of being in contact with the photosensitive belt 10, the drip line D is removed from the photosensitive belt 10 and flows along the outer circumference of the squeeze roller 24. It is lowered and removed by the plate-shaped blade 26 which contacts the surface of the squeeze roller 24 and scrapes off the developer.

However, the conventional wet electrophotographic printing machine as described above has a photosensitive belt 10 in order to remove residual developer remaining on the photosensitive belt 10 from the developing roller 22 to the squeeze roller 24 after the developing operation. Additional movements are needed to reduce the running speed of the vehicle. In addition, there is another additional operation of reversely rotating the squeeze roller 24, and the image area of the photosensitive belt 10 during the reverse rotation is damaged by friction with the squeeze roller 24, resulting in a shortened life.

The present invention has been made to improve the above problems, and provides a cleaning method of a wet electrophotographic printing machine which can effectively remove the developer remaining on the photosensitive belt from the developing roller to the squeeze roller after the developing operation. Has its purpose.

1 is a schematic diagram illustrating a general wet electrophotographic printing press,

FIG. 2 is a schematic diagram illustrating a drip line removal operation remaining in the photosensitive belt of FIG. 1;

3 is a configuration diagram for explaining a cleaning method of a wet electrophotographic printer according to the present invention;

4 is a schematic diagram illustrating the main part of FIG. 3;

5 is a flowchart sequentially illustrating a cleaning method of a wet electrophotographic printer according to the present invention.

<Explanation of symbols for the main parts of the drawings>

10,110 ... Photosensitive belt 11,111 ... Guide roller

12,112 ... Main corona 13,113 ... Laser injection unit

15,115 ... drying unit 16,116 ... transfer roller

20,120 ... Developing machine 22,122 ... Developing roller

24,124 ... Squeeze Roller 26 ... Blade

28,128 ... Topping Corona 30,130 ... Warrior Unit

141 ... cleaning roller 141a ... heating element

143 ... cleaning backup roller 145 ... blade member

147. Suction storage member

In order to achieve the above object, the cleaning method of the wet electrophotographic printing machine according to the present invention includes a developing roller which rotates while maintaining a developing gap with a photosensitive belt, and is always fixed and rotated in a pressurized state to the photosensitive belt. In the cleaning method of a wet electrophotographic printing press for removing the residual developer in the photosensitive belt between the squeeze roller which is driven in the same direction as the driving direction of the photosensitive belt, the electric charge and having a predetermined color A developing step of attaching a developer mixed with a solid toner and a liquid carrier to the electrostatic latent image region of the photosensitive belt using the developing roller, and squeezing the attached developer using the squeeze roller; And a cleaning step of removing the residual developer by sticking the residual developer stuck on the photosensitive belt between the developing roller and the squeeze roller after the development mode is finished, wherein the cleaning step includes: Residual developer transfer step of transferring the residual developer to the surface of the photosensitive belt; A squeegeeing step of allowing a portion of the toner and the liquid carrier in the residual developer to adhere to a surface of the photosensitive belt while the residual developer passes through a squeeze roller; And a residual developer removal step of removing the residual developer fixed to the photosensitive belt by being transferred to the surface of the cleaning roller by a difference in surface energy.

According to the present invention, after the cleaning step, if there is no development mode command for a predetermined time, the power saving step for releasing the pressure of the developing roller and the squeeze roller to switch to the home mode;

According to the invention, the cleaning step, the residual developer transfer step of transferring the residual developer to the surface of the photosensitive belt; A squeegeeing step of allowing a portion of the toner and the liquid carrier in the residual developer to adhere to a surface of the photosensitive belt while the residual developer passes through a squeeze roller; And a residual developer removing step of removing and removing the residual developer fixed to the photosensitive belt to the surface of the transfer roller.

According to the present invention, in the residual developer transition step, the surface potential of the photosensitive belt is in an off state, and the developing potential of the developing roller is turned on at a predetermined voltage.

Therefore, after the developing operation, it is possible to remove by the simple operation of transferring the remaining developer on the photosensitive belt from the developing roller to the squeeze roller to the photosensitive belt, and the reverse rotation of the squeeze roller becomes unnecessary, and the friction By preventing the photosensitive belt from being damaged, the life of the photosensitive belt can be extended. In addition, by eliminating the blade, which is a separate component, there is a feature in that the developing body and the entire printing machine can be miniaturized.

With reference to the accompanying drawings, such a feature will be described in detail a cleaning method of a wet electrophotographic printer according to the present invention.

FIG. 3 is a configuration diagram illustrating a cleaning method of a wet electrophotographic printing press according to the present invention, and FIG. 4 is a schematic diagram illustrating an essential part of FIG. 3.

Hereinafter, a cleaning method of a wet electrophotographic printer according to the present invention will be described with reference to FIGS. 3 and 4, but the basic structure thereof is not different from that of a conventional wet electrophotographic printer. That is, the photosensitive belt 110, the developing roller 122 and the squeeze roller 124 is basically provided.

However, in the cleaning method of the wet electrophotographic printing press according to the present invention, after the completion of the developing mode, the residual developer (D) which is stagnant on the photosensitive belt 110 between the squeeze roller 124 and the developing roller 122 is photosensitive. The point of fixation on the surface of the belt 110 and the point of removing the residual developing solution D fixed on the surface of the photosensitive belt 110 by the cleaning means is different from the conventional.

In order to satisfy this, the squeeze roller 124 does not rotate in the removal mode of the residual developing solution D, and the squeeze roller 124 is operated in the same direction as the traveling direction of the photosensitive belt 110 as in the developing mode. It is always fixed so that only driven rotation. The developing roller 122 maintains the developing gap G with the photosensitive belt 110 as it is. In addition, in the developing roller 122 in the residual developer removing mode, the developing potential of the developing roller 122 must be maintained at a predetermined voltage in order to fix the residual developing solution D to the surface of the photosensitive belt 110 described later. The main corona 112 and the topping corona 128 in the developer removal mode are transferred to the photosensitive belt 110 so that the residual developer D can be transferred to the surface of the photosensitive belt 110 by the potential difference with the developing potential. The potential application is turned OFF.

The cleaning means is provided with a cleaning roller 141 and a cleaning backup roller 143 for removing the residual developer (D) adhered to the surface of the photosensitive belt 110 as a known element.

The cleaning roller 141 is installed to be in contact with and spaced apart from the surface of the photosensitive belt 110, transfer the residual developer (D) to the surface by the difference in surface energy according to the temperature difference with the photosensitive belt 110. The heating member (141a) is built in the core portion to receive. Meanwhile, the cleaning roller 141 is installed to correspond to the cleaning backup roller 143 which rotates with the photosensitive belt 110 interposed therebetween.

The blade member 145 is installed on the outer circumferential surface of the cleaning roller 141 to scrape and remove the residual developer D transferred to the outer circumferential surface. In addition, the blade member 145 is further provided with a suction storage member 147 to prevent the residual developer (D) scraped off by the blade member 145 to fall back to the surface of the photosensitive belt 110. .

On the other hand, the developing roller 122 and the squeeze roller 124 to the developing roller 122 and the squeeze roller 124 to prevent additional damage of the photosensitive belt 110 is maintained in a tension state for a long time after the end of cleaning. Lifting means (not shown) is further provided for lowering to switch to the home mode.

Hereinafter, a cleaning method of a wet electrophotographic printing press according to the present invention will be described in detail with reference to the accompanying drawings, which will be described below with reference to FIGS. 3 and 4.

5 is a flowchart sequentially illustrating a cleaning method of a wet electrophotographic printer according to the present invention.

3 to 5, in the development mode (510 in FIG. 5), the developing roller 122 is developed between the developing roller 122 and the photosensitive belt 110 by a predetermined injection means (not shown). The developer supplied to the gap G is attached to the electrostatic latent image region formed on the photosensitive belt 110. Here, the developing solution is a developing solution in which a solid toner having a charge and a predetermined color is mixed with a liquid carrier, and is different from a potential (about 450 V) of the developing roller 122 and a potential (about 150 V) of the electrostatic latent image region. This makes it possible to attach to the latent electrostatic image area.

In addition, the developer attached as described above is squeezed by the squeeze roller 124 which is driven in the same direction as the traveling direction of the photosensitive belt 110 so that the toner in the developer is filmed, and most carriers are squeezed out. Removed.

In this case, it is determined whether the development mode (510 of FIG. 5) continues as described above by the presence or absence of an input print command (520 of FIG. 5). Therefore, when no print command is input, the developing mode (510 in FIG. 5) is terminated. That is, the developing step is finished. At this time, in the photosensitive belt 110 between the developing roller 122 and the squeeze roller 124, the remaining developer D, which is stuck as it is, does not drop and remains stagnant.

On the other hand, if it is determined that the development mode is terminated (520 in FIG. 5), the developing roller 122 as the cleaning mode 530 thereafter maintains the development gap G with the photosensitive belt 110 unlike the prior art. The predetermined development potential is kept applied (531 in Fig. 5). Here, the potential should not be applied to the photosensitive belt 110, in order to do so, the main corona 112 and the topping corona 128 are kept off (OFF) (531 in FIG. 5). The reason for this is to allow a portion of the toner and liquid carrier of the residual developer D to be transferred to the surface of the photosensitive belt 110.

That is, the potential of the photosensitive belt 110 becomes zero, and the residual developer D is transferred to the surface of the photosensitive belt 110 by the potential difference with the developing roller 122 (533 in FIG. 5). This is a natural phenomenon that occurs because the residual developing solution D, which is charged, is attracted to the photosensitive belt 110 having a zero potential by the developing roller 122 to which a predetermined potential is applied.

In this state, when the photosensitive belt 110 passes through the squeeze roller 124 which is driven in the same direction as the traveling direction of the photosensitive belt 110, as in the development mode (510 of FIG. 5), the residual developer (D) is pressed onto the surface of the photosensitive belt 110 (535 in Fig. 5).

Then, some of the toner particles T and the liquid carrier in the residual developer D adhere to the surface of the photosensitive belt 110, and most of the liquid carrier is squeezed out and falls into the developing unit 120.

In this cleaning mode (530 of FIG. 5), unlike the conventional method, an additional operation of rotating the squeeze roller 124 in order to remove the residual developer (D), for example, a drip-line, and the developing roller 122. It is possible to eliminate the lowering operation of), and by squeezing the squeeze roller 124 only in the same direction as the driving direction of the photosensitive belt 110 in a fixed state to simplify the printing machine structure and improve the printing efficiency. do. In addition, it is possible to extend the life of the photosensitive belt 110 by preventing the photosensitive belt 110 from being damaged by friction with the squeeze roller 124 is reversely rotated.

Thereafter, the photosensitive belt 110 traveling passes through the drying unit 115. Then, the residual developer D adhering to the surface of the photosensitive belt 110 is dried in the drying unit 115 so that the toner particles T in the residual developer D are fixed to the surface of the photosensitive belt 110, and the liquid phase Carrier is dried and evaporated.

The toner particles T fixed to the surface of the photosensitive belt 110 are removed by the cleaning means (537 in FIG. 5). Prior to this, the transfer roller 116 of the transfer unit 130 should be kept spaced apart from the photosensitive belt 110. The reason is to prevent the toner particles T fixed to the surface of the photosensitive belt 110 from being transferred to the surface of the transfer roller 116. In this case, the cleaning roller 141 is in a state in which it is spaced apart from the photosensitive belt 110 in the developing mode (510 of FIG. 5), and then converted to the cleaning mode (530 of FIG. 5) while the photosensitive belt ( 110) is in contact with the surface.

Referring to the action of the cleaning means according to the cleaning mode (530 in Figure 5) in more detail, the toner particles (T) fixed to the surface of the photosensitive belt 110 and the cleaning roller 141 and the mutually compressed state It passes between the cleaning backup roller 143. Then, since the heating member 141a is embedded in the core of the cleaning roller 141, the toner particles T may have a difference in surface energy due to the temperature difference between the photosensitive belt 110 and the cleaning roller 141 due to the heat. It is transferred to the cleaning roller 141 surface. The toner particles T transferred to the surface of the cleaning roller 141 are scraped off and removed from the tip of the blade member 145, and the removed toner particles T are sucked into the suction storage member 147 and stored therein. Thus, the residual developer D stagnant on the photosensitive belt 110 between the squeeze roller 124 and the developing roller 122 is completely removed by this simple operation.

On the other hand, according to the present invention, unlike the transfer to remove the toner particles (T) fixed to the photosensitive belt 110 to the cleaning roller 141 as described above, by lowering the transfer roller 116 to the photosensitive belt After contacting 110, the toner particles T fixed to the photosensitive belt 110 may be transferred to a surface of the transfer roller 116 and removed by a cleaning device (not shown) installed separately.

In the cleaning mode (530 of FIG. 5), unlike the related art, a blade (26 of FIG. 1) that is installed in contact with the squeeze roller 124 may be excluded so that the contact point between the squeeze roller 124 and the blade (26 of FIG. 1) may be excluded. The operation of eliminating the hold-up volum and the means thereof can be omitted, thereby simplifying the printing structure and improving the printing efficiency.

Unlike the above description, after the above-described cleaning mode (530 of FIG. 5) is completed, the developing roller 122 and the squeeze roller 124 may be switched to the home mode in the following cases.

First, after completion of the cleaning mode (530 of FIG. 5), even if a predetermined time elapses, if there is no command of the developing mode (510 of FIG. 5), a separate lifting means (not shown) is driven to drive the squeeze roller 124 and The developing unit 120 including the developing roller 122 is switched to the home mode. That is, if the user does not have a development mode command (510 of FIG. 5) during the preset power save (540 of FIG. 5), the pressure of the developing roller 122 and the squeeze roller 124 is released to switch to the home mode. (550 of FIG. 5). Here, the reason for switching the developer 120 to the home mode is that when the photosensitive belt 110 is rotated for a long time while maintaining a tension state for a predetermined time of a predetermined power save, the result is added to the photosensitive belt 110. This is because damage is caused.

In addition, when the photosensitive belt 110 is replaced, the developing roller 122 and the squeeze roller 124 are switched to the home mode (550 of FIG. 5).

After that, when the development mode (510 of FIG. 5) command is input again, after the development mode ends (520 of FIG. 5), the residual developer D is cleaned in the same manner as described above.

As described above, the cleaning method of the wet electrophotographic printing press according to the present invention is characterized by a simple operation of transferring the remaining developer on the photosensitive belt from the developing roller to the squeeze roller to the photosensitive belt after the developing operation. The first advantage is that it can be removed.

In addition, there is a second advantage in that the reverse rotation operation of the squeeze roller is unnecessary and the life of the photosensitive belt can be extended by preventing the photosensitive belt from being damaged by the friction.

In addition, by excluding the squeeze blade which is a separate part, there is a third advantage in that the developing body and the printing machine as a whole can be miniaturized.

Claims (4)

The photosensitive roller between the developing roller which rotates while maintaining a developing gap with the photosensitive belt, and a squeeze roller which is fixedly rotated while being constantly fixed in a pressurized state to the photosensitive belt, but is driven only in the same direction as the traveling direction of the photosensitive belt. In the cleaning method of a wet electrophotographic printing machine for removing residual developer that is stuck in a belt, The developing step of attaching a developer mixed with a solid toner having a predetermined color and a liquid carrier to the electrostatic latent image area of the photosensitive belt using the developing roller, and squeezing the attached developer using the squeeze roller. ; And After the development mode, the cleaning step to remove the residual developer by sticking the residual developer in the photosensitive belt between the developing roller and the squeeze roller to the surface of the photosensitive belt; including the cleaning step, Residual developer transfer step of transferring the residual developer to the surface of the photosensitive belt; A squeegeeing step of allowing a portion of the toner and the liquid carrier in the residual developer to adhere to a surface of the photosensitive belt while the residual developer passes through a squeeze roller; And a residual developer removal step of removing the residual developer fixed to the photosensitive belt by being transferred to the surface of the cleaning roller by a difference in surface energy. The method of claim 1, After the cleaning step, And a power save step of releasing the pressure of the developing roller and the squeeze roller to switch to the home mode when there is no developing mode command for a predetermined time. The method of claim 1, The cleaning step, Residual developer transfer step of transferring the residual developer to the surface of the photosensitive belt; A squeegeeing step of allowing a portion of the toner and the liquid carrier in the residual developer to adhere to a surface of the photosensitive belt while the residual developer passes through a squeeze roller; And And a residual developer removal step of removing the residual developer adhered to the photosensitive belt to the surface of the transfer roller to remove the residual developer. The method of claim 1, In the residual developer transition step, The surface potential of the photosensitive belt is in an off state, and the developing potential of the developing roller is turned to a predetermined voltage.