KR100230313B1 - Development apparatus of liquid electrographic printer - Google Patents

Abstract

A developing apparatus of a wet electrophotographic color printing machine having an improved structure of a developing unit is disclosed.

The developing apparatus of the disclosed wet electrophotographic color printer includes a photosensitive medium rotatably installed, a laser scanning unit for irradiating light to an image recording position of the photosensitive medium, and a developer for supplying and attaching liquid toner to the photosensitive position of the photosensitive medium. The developing device includes: a developing container provided at one side of the photosensitive medium for containing liquid toner, supply adjusting means for selectively supplying liquid toner from a plurality of liquid toner cartridges having liquid toners of different colors; A developing roller installed near the photosensitive medium in the developing container to attach the liquid toner supplied from the liquid toner cartridge to the photosensitive position of the photosensitive medium, and collecting the remaining liquid toner attached to the photosensitive position of the photosensitive medium from the developing container; Number of feedbacks to feed back to the liquid toner cartridge for each color And characterized in that it comprises a squeeze roller to remove the liquid carrier adhering to the photosensitive position of the photosensitive medium.

Description

Developing apparatus for wet electrophotographic color printer

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wet electrophotographic printing machine, and more particularly, to a developing device for a wet electrophotographic color printing machine having an improved structure of a developing unit.

In general, an electrophotographic printing machine such as a laser printer or a copier has a dry electrophotographic printer using a powder toner as a developing method, and a wet electrophotographic method using a liquid toner mixed with a powder toner in a liquid carrier. There is a printing press. However, the dry electrophotographic printing machine has a problem of resolution caused by the size limitation of the toner particles, or a problem that toner dust generated when replacing the toner is very harmful to the human body. Therefore, the printing quality is better than the dry electrophotographic printing machine, and a wet electrophotographic printing machine which can prevent damage caused by toner dust is expected to be used.

FIG. 1 is a schematic view of a wet electrophotographic color printer employing a conventional developing apparatus, and FIG. 2 is an enlarged schematic view of the developing device of FIG.

Referring to the drawings, a developing apparatus of a conventional wet electrophotographic color printing machine has a photosensitive belt 20 which is rotated and moved in a given path by three guide rollers 10 and a photosensitive belt 20. And a developing unit 50 for recording the image by causing the liquid toner to adhere to the position.

The organic photoconductor (OPC) belt 20 is made of a material in which when the light is irradiated, the potential of the photosensitive portion is changed compared to the surrounding potential.

The developing unit 50 includes a laser scan unit (LSU) 51, 53, 55, 57 for irradiating light to a position of the photosensitive belt 20 to record an image, and a photosensitive belt. And developer (52) (54) (56) 58 for attaching liquid toner to the photosensitive position of (20). At this time, the laser scanning units 51, 53, 55, 57, and the developer 52, 54, 56, 58 are alternately paired to form each color, that is, red (R) and green (G). Four pairs are provided side by side so that the images of blue (B) and black (BK) can be recorded.

Each of the developing devices 52, 54, 56, 58 is provided with a developing container 61 containing liquid toner as shown in FIG. 2, and the photosensitive belt 20 inside the developing container 61. It is rotated to be almost in contact with the developing roller 63 for attaching the liquid toner to the photosensitive position of the photosensitive belt 20 in accordance with the rotation thereof, and is installed in almost contact with the developing roller 63, And a cleaning roller 64 for removing the liquid toner remaining on the surface, and a pair of squeeze rollers 65 and 66 for removing the liquid toner excessively buried in the photosensitive position. The liquid toner is then pumped from the liquid toner cartridge 69 by the pump 67 and supplied through the tube 68.

When recording an image, first, the latent image of the previous step is removed by the light irradiated from the reset unit 30 to the photosensitive belt 20. In addition, the photosensitive belt 20 has a predetermined potential by one discharge unit (not shown). Then, for example, the red image recording position of the photosensitive belt 20 is reduced by the light irradiated from the one laser scanning unit 51, and this photosensitive portion is replaced by one developing unit 52 according to the rotation of the guide roller 10. 54, 56, 58, the liquid toner adheres to the photosensitive position of the photosensitive belt 20 due to the attractive force due to the potential difference between the photosensitive portion and the liquid toner. The latent image during red image recording is removed by causing the photosensitive belt 20 to have a predetermined potential by another discharge unit, and the other laser scanning units 51, 53, 55, 57 and the developer 52 ( 54, 56 and 58, green, blue and black images are formed step by step on the photosensitive belt 20 in the same manner as described above. Therefore, images of the red, green, blue, and black colors can be obtained, and color images by the combination of these colors can also be obtained. Here, the four pairs of laser scanning units 51, 53, 55, 57 and the developer 52, 54, 56, 58 are driven independently of each other. Therefore, desired single color or multicolor images can be selectively formed. On the other hand, the liquid carrier of the liquid toner deposited on the photosensitive belt 20 by the conventional developing device as described above is removed from the drying unit 70 of the wet electrophotographic color printer, and only the toner remains in the image recording position. . This image, i.e., the toner attached to the image recording position, is to be printed on the paper 1 by the transfer roller 81.

However, the developing apparatus of the conventional wet electrophotographic color printer as described above has four developing devices 52, 54, 56, 58 and four laser scanning units having the same structure for forming a color image. Since 51, 53, 55, and 57 are employed, they are not only difficult to install, but also have a complicated structure and a high manufacturing cost.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object thereof is to provide a developing device for a wet electrophotographic color printing machine having a structure capable of reducing the number of developing devices and laser scanning units.

1 is a view schematically showing a wet electrophotographic color printer employing a conventional developing apparatus;

2 is a schematic view of the developing device of FIG.

3 is a schematic view of a wet electrophotographic color printer employing a developing apparatus according to an embodiment of the present invention;

4 is a view schematically showing an example of the supply adjusting means and the feedback means of FIG.

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

120 ... photosensitive medium 140 ... laser scanning unit

200 ... developing 210 ... developing container

220 ... supply control means 221, 241 ... valve unit

230 ... developing roller 240 ... feedback means

250 ... Squeeze Roller 260 ... Liquid Toner Cartridge

270,280 ... pump

The developing apparatus of the wet electrophotographic color printing machine according to the present invention for achieving the above object comprises a photosensitive medium rotatably installed; A laser scanning unit for irradiating light to an image recording position of the photosensitive medium; A developing device for a wet electrophotographic color printer, comprising: a developing container provided at one side of the photosensitive medium to receive liquid toner; Supply adjusting means for adjusting liquid toner to be selectively supplied from a plurality of liquid toner cartridges having liquid toners of different colors; A developing roller installed in the developing container in proximity to the photosensitive medium to attach the liquid toner supplied from the liquid toner cartridge to a photosensitive position of the photosensitive medium; Feedback means for collecting the remaining liquid toner attached to the photosensitive position of the photosensitive medium from the developing container to be fed back to the liquid toner cartridge for each color; And a squeeze roller for removing the liquid carrier attached to the photosensitive position of the photosensitive medium.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

3 is a view schematically showing a wet electrophotographic color printer employing a developing apparatus according to an embodiment of the present invention, and FIG. 4 is a view schematically showing an example of a supply control means and a feedback means of FIG. 3.

Referring to the drawings, the developing apparatus of the wet electrophotographic color printer according to the present invention includes a photosensitive medium 120 rotatably installed and a laser scanning unit 140 for irradiating light to an image recording position of the photosensitive medium 120. And a developer 200 for supplying and attaching liquid toner to a photosensitive position of the photosensitive medium 120.

When the photosensitive medium 120 is irradiated with light, the photosensitive medium 120 is made of a material whose potential of the photosensitive portion is different from that of the surroundings. As the photosensitive medium 120, a photosensitive belt or a photosensitive drum may be employed. FIG. 3 illustrates an example in which a photosensitive drum is used as the photosensitive medium 120. The laser scanning unit 140 irradiates light to an image recording position of the photosensitive medium 120 to reduce the position thereof.

The developing unit 200 is provided on one side of the photosensitive medium 120, a developing container 210 for receiving liquid toner, supply control means 220 for adjusting the liquid toner to be selectively supplied for each color, and liquid A developing roller 230 for attaching the toner to the photosensitive medium 120, a feedback means 240 for collecting the liquid toner, and a squeeze roller for removing the liquid carrier attached to the photosensitive position of the photosensitive medium 120 ( 250).

The supply adjusting means 220 controls the supply of the liquid toner by selectively passing one color of the liquid toner of the four colors of liquid toners supplied from the plurality of liquid toner cartridges 260 having the liquid toners of different colors. That is, it serves as a switch so that the liquid toner of a color to form an image can be supplied. The supply regulating means 220 is configured to include a valve unit 221 and a pump 270 to output one output selectively for four inputs.

As shown in FIG. 4, the valve unit 221 may include first, second, and third valves 221a, 221b, and 221c configured to selectively output one output to two inputs. The second valve 221b selectively passes a liquid toner of one color among two colors of liquid toners input from the liquid toner cartridge 260 to the input terminals 224 and 225 through two tubes. The third valve 221c selectively passes a liquid toner of one color among two colors of liquid toners input from the liquid toner cartridge 260 to the input terminals 222 and 223 through two tubes. The first valve 221a selectively passes the liquid toner of a color to form an image among the liquid toners of other colors coming from the second and third valves 221b and 221c, and outputs the result to the output terminal 226. Let's do it. Here, reference numerals in parentheses in FIG. 4 are used to describe the valve unit 241 of the feedback means 240 described later.

The pump 270 is provided in the middle of the tube connected to the output end 226 of the valve unit 221 so that the liquid toner can be smoothly supplied to the developing roller 230.

As such, the input terminals 222, 223, 224, and 225 of the supply control means 220 and the liquid toner cartridge 260 are connected by four tubes to supply liquid toner for each color. . The output end 226 of the supply adjusting means 220 is connected to one tube, and the outlet 226a of the tube faces the developing roller 230. Therefore, for example, in forming an image of a red color, the liquid toner of a red color is supplied from the liquid toner cartridge 260 by this supply adjusting means 220, and can be supplied in the same manner to other colors. The liquid toner cartridge 260 may be yellow (Y), magenta (M), cyan (C) and black (BK) or red (R), green (G), blue (B), and black (BK) color. Liquid toners are provided so that they can be supplied independently of each other.

The developing roller 230 is installed in the developing container 210 to be close to the photosensitive medium 120 and rotates almost in contact with the photosensitive medium 120, thereby causing liquid toner on the photosensitive medium 120 according to the rotation thereof. Attach. And the liquid toner remaining on the surface of the developing roller 230 can be removed by a cleaning roller (not shown) installed in almost contact with the developing roller 230.

The feedback means 240 is attached to the photosensitive position of the photosensitive medium 120 and provided to feed back the liquid toner collected in the developing container 210 to the liquid toner cartridge 260 for each color. The feedback means 240 includes a valve unit 241 capable of outputting four outputs to the liquid toner cartridge 260 for each color selectively for one input, and a pump 280 for smoothing feedback of the liquid toner. It is configured to include.

The valve unit 241 may be composed of first, second and third valves 241a, 241b and 241c configured to selectively output two outputs for one input as shown in FIG. 4. have. The first, second and third valves 241a, 241b and 241c cause the one-color liquid toner collected in the developing container 210 to be fed back to the liquid toner cartridge corresponding to the color, and the supply adjustment It is operated opposite to the first, second and third valves 221a, 221b and 221c of the means 220.

The pump 280 allows the liquid toner collected in the developing container 210 to be smoothly fed back to the liquid toner cartridge 260.

In this way, the input terminal 246 of the feedback means 240 is connected to the developing container 210 by one tube, and the liquid toner collected in the developing container 210 is returned to the liquid toner cartridge 260 for each color. The four output stages 242, 243, 244 and 245 of the feedback means 240 are connected to the liquid toner cartridge 260 by four tubes so as to be accessible. Therefore, for example, after the image of the red color is formed, the liquid toner of the red color is recovered from the developing container 210 to the liquid toner cartridge 260 by the feedback means 240, and is recovered in the same manner for the other colors. Can be. That is, the feedback means 240 may be operated in the reverse order to the supply control means 220.

Hereinafter, the operation of the developing apparatus of the wet electrophotographic color printer according to the present invention will be described with reference to FIG. 2.

For example, when a yellow image is recorded on the photosensitive medium 120, the latent image of the previous step is removed by the light irradiated from the reset unit 170 of the wet electrophotographic color printer, and the predetermined portion is discharged by a discharge unit (not shown). Light is irradiated from the laser scanning unit 140 onto the photosensitive medium 120 having the potential of, thereby reducing the yellow image recording position of the photosensitive medium 120. The photosensitive medium 120 is rotated so that the photosensitive position is facing the developing roller 230. When the yellow liquid toner is supplied through the tube by the supply adjusting means 220, the liquid toner passes between the photosensitive medium 120 and the developing roller 230 as the developing roller 230 rotates. Due to the potential difference between the toner and the photosensitive position, the liquid toner is buried at the photosensitive position, and the remaining liquid toner is collected in the developing container 210.

The liquid carrier buried in the photosensitive position is removed by the pair of squeeze rollers 250 which are rotated to be in contact with the photosensitive medium 120 and collected in the developing container 210. When a certain amount of liquid toner is collected in the developing container 210, the feedback means 240 is operated so that the liquid toner is fed back to the yellow color liquid toner of the liquid toner cartridge 260. While the yellow image formation is continued, the feedback means 240 may be intermittently operated as liquid toner is collected in the developing container 210. After the yellow image is formed, all of the liquid toner in the developing container 210 is recovered to the liquid toner cartridge 260.

When recording images of other colors such as magenta, cyan and black colors, the image is recorded on the photosensitive medium 120 through the above process. Therefore, when the photosensitive medium 120 is rotated three or four turns, the composite color image is recorded on the photosensitive medium 120, and thus can be selectively operated when a single color or multicolor color image is formed. As described above, the image recorded on the photosensitive medium 120 is dried in the drying unit 170 and is printed on the paper 1 by a predetermined transfer means, for example, the transfer roller 181. The same applies to the case where the liquid toner cartridge 260 is provided to record images of red, green, blue and black colors. The recording order of the color image may be changed.

The developing apparatus of the wet electrophotographic color printer according to the present invention as described above is easy to install the developer and the laser scan unit because the color image is recorded on the photosensitive medium by using one developer and one laser scan unit. In addition, the structure is simple. As a result, manufacturing costs can be lowered.

Claims (3)

A photosensitive medium rotatably installed; A laser scanning unit for irradiating light to an image recording position of the photosensitive medium; A developing device for a wet electrophotographic color printing machine comprising: a developing device for supplying and attaching a liquid toner to a photosensitive position of the photosensitive medium; The developing device is provided on one side of the photosensitive medium to contain a liquid toner; Supply adjusting means for adjusting liquid toner to be selectively supplied from a plurality of liquid toner cartridges having liquid toners of different colors; A developing roller installed in the developing container in proximity to the photosensitive medium to attach the liquid toner supplied from the liquid toner cartridge to a photosensitive position of the photosensitive medium; Feedback means for collecting the remaining liquid toner attached to the photosensitive position of the photosensitive medium from the developing container to be fed back to the liquid toner cartridge for each color; And a squeeze roller for removing the liquid carrier attached to the photosensitive position of the photosensitive medium. According to claim 1, wherein the supply control means, A valve unit configured to selectively pass one color of the liquid toner of the four colors of liquid toner supplied from the liquid toner cartridge; And a pump for smoothly supplying liquid toner from the valve unit side to the developing roller. The method of claim 1, wherein the feedback means, A valve unit configured to selectively feed the liquid toner collected in the developing container by color to the liquid toner cartridge; And a pump for smoothly feeding back the liquid toner collected in the developing container toward the liquid toner cartridge.

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