KR100359094B1 - Developing unit for liquid electrographic printer - Google Patents

Abstract

The developing unit of the wet electrophotographic printing machine according to the present invention is for developing a developer in an electrostatic latent image area of a photosensitive belt which is supported by a plurality of rollers and travels on an endless track, and a developing roller which is lifted up and down under the photosensitive belt; In the developing unit of the wet electrophotographic printing machine having a manifold which is supported by the developing roller and ejects the developer into a developing gap formed between the developing roller and the photosensitive belt, the manifold is provided with a casing member. The casing member is characterized in that the inclined portion of a gentle shape is provided so that the developer which overflows in the opposite direction to the developing roller flows down without being accumulated in the body.

Therefore, by improving the shape of the manifold, the developer is prevented from accumulating on the body, and if excessive developer overflows, it is prevented from falling into peripheral devices such as a laser scanning unit, thereby preventing contamination of peripheral devices. The advantage is that the printing state is kept clear.

Description

Developing unit for wet electrophotographic printing machine {Developing unit for liquid electrographic printer}

The present invention relates to a developing unit of a wet electrophotographic printing press, and more particularly, to a developing unit of a wet electrophotographic printing press having an improved structure of a manifold for ejecting a developer to a developing roller.

Generally, a wet electrophotographic printing machine such as a laser printer or a copying machine develops a developer mixed with a solid toner having a predetermined color and a liquid carrier having a solvent function in an electrostatic latent image area formed on a photosensitive member such as a photosensitive belt to produce a desired image. It is a kind of image forming apparatus that obtains.

1 is a configuration diagram schematically showing an example of a general wet electrophotographic printing press.

Referring to FIG. 1, an image is photographed on a photosensitive belt 10 supported by a plurality of rollers 11 and traveling in an endless track, a developing unit 20, and a recording paper P for developing the photosensitive belt 10. A transfer unit 30 for transferring is provided.

The photosensitive belt 10 is maintained in a charged state at a predetermined potential by the charger 12, and the charging potential is set to a predetermined potential by a beam scanned from the laser scanning unit 13 installed near the photosensitive belt 10. By changing to the electrostatic latent image is formed. The image formed on the electrostatic latent image passes through a predetermined path, is then transferred to the transfer roller 14 of the transfer unit 30 by the surface energy difference, and then passes between the transfer roller 14 and the fixing roller 15. It is printed on the paper P.

FIG. 2 is a schematic view illustrating a development unit part of FIG. 1.

Referring to FIG. 2, the developing unit 20 includes a developing roller 22, a brush roller 27, a blade 28, primary and secondary squeeze rollers 24 and 25, and a manifold 40. ), A developing tank 21 and a tray 26 are provided.

The developing tank 21 is supported by the developing roller 22 and accommodates the developer remaining in the developing process by the developing roller 22 to scrape the developer remaining on the surface of the developing roller 22 therein. The blade 28 and the developing roller 22 and the brush roller 27 for cleaning the developer remaining on the blade 28 are provided.

The manifold 40 is supported by the developing roller 22, and ejects the developing solution into the developing gap G formed between the developing roller 22 and the photosensitive belt 10 to electrostatic latent images of the photosensitive belt 10. It is provided to develop an area.

The primary and secondary squeeze rollers 24 and 25 are for squeezing by squeezing excessive developer developed on the photosensitive belt 10. Then, the developing solution in the developing tank 21 or the developing solution squeezed by the squeeze rollers 24 and 25 and scratched by the blades 28 are collected at the lower end of the tray 26, and the collected developing solutions are routed in a predetermined path. It is recovered through a working solution tank (working solution tank; not shown).

The manifold 40 as described above includes an inlet portion 41 and a casing member 43 provided with the ejection portion 42, and the casing member 43 does not overflow the developer to overflow. In order to cut off, the dam part 44 which maintains the predetermined space of "V" shape is integrally formed.

The dam 44 is provided on the upper part of the blower 42 and extends from the first inclined path 44a and the first inclined path 44a so as to be inclined downward toward both ends with a predetermined center line as a vertex. It is comprised by the 2nd inclination path 44b inclined so that it might incline toward the inside of the developing tank 21. As shown in FIG.

By the way, in the above structure, even if the developer flows into the developing tank 21 along the dam 44, the developer is always accumulated in a predetermined space of the dam 44. The developing solution solidifies and accumulates. In this case, if the amount of the developer supplied to the developing roller 22 through the jetting part 42 is excessive and the amount overflows, the developer is manifolded as shown by the dotted arrows in FIG. 2. There is a risk of falling back to the peripheral device such as a laser scanning unit (13 in FIG. 1) installed in the adjacent position of the tray 26 without being introduced into the tray 26 by overflowing the outer peripheral surface of the folder 40.

As such, when the laser scanning unit (13 in FIG. 1) is contaminated, it is impossible to form a precise electrostatic latent image on the transfer surface of the photosensitive belt 10, thereby degrading print quality. Therefore, there is a demand for a structure of a manifold in which the developer can be recovered into the tray 26 even if it overflows.

SUMMARY OF THE INVENTION The present invention was created to improve the above problems. The developing unit of a wet electrophotographic printing machine having an improved structure of a manifold, which is installed close to the developing roller and ejects the developer into a developing gap formed between the developing roller and the photosensitive belt. The purpose is to provide.

1 is a configuration diagram schematically showing an example of a general wet electrophotographic printing press,

2 is a configuration diagram schematically showing a development unit part of FIG.

3 is a configuration diagram schematically showing a developing unit of a wet electrophotographic printing press according to an embodiment of the present invention.

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

10,110 ... Photosensitive belt11,102 ... Roller

12 ... charger13 ... LSU

14 ... Transfer Roller 15 ... Fixing Roller

20,200 ... Developing unit 21,210 ... Developing tank

22,220 ... Developing roller 40,400 ... Manifold

24,240 ... 1st squeeze roller 25 ... 2nd squeeze roller

26,260 ... Tray 30 ... Transfer Unit

41,410 ... Inlet 42,420 ... Ejection

43,430 Casing member 44 Dam portion

44a ... at the first slope 44b ... at the second slope

240a, 280 ... blade 270 ... cleaning roller

430a ... slope 450 ... guide plate

In order to achieve the above object, the developing unit of the wet electrophotographic printing machine according to the present invention is for developing a developer in an electrostatic latent image region of a photosensitive belt that is supported by a plurality of rollers and travels on an endless track. A developing unit of a wet electrophotographic printing machine, comprising: a developing roller which is raised and lowered at a; and a manifold supported by the developing roller to eject the developer into a developing gap formed between the developing roller and the photosensitive belt. Is provided with a casing member, characterized in that the casing member is provided with an inclined portion of a gentle shape so that the developer that overflows in the opposite direction to the developing roller flows down to the body.

According to the present invention, it is preferable that one side of the casing member is further provided with a guide plate to block the overflow of the developing solution to the peripheral device.

Therefore, by improving the shape of the manifold, the developer is prevented from accumulating on its body, and if excessive developer overflows, it prevents it from falling into peripheral devices such as a laser scanning unit, thereby preventing contamination of peripheral devices. Its characteristics are that it keeps the printing state clear.

With reference to the accompanying drawings, such a feature will be described in detail a developing unit of a wet electrophotographic printing press according to an embodiment of the present invention.

3 is a schematic diagram illustrating a developing unit of a wet electrophotographic printer according to an embodiment of the present invention.

Referring to FIG. 3, the developing unit 200 of the present invention is supported by a plurality of rollers 102, and includes a photosensitive belt 110 for traveling in an endless track, and a tray 260 installed below the photosensitive belt 110. And a developing roller 220 for attaching a developer to the electrostatic latent image area formed in a predetermined region of the photosensitive belt 110, and a developing tank 210 supported by the developing roller 220 to accommodate the developer therein. ). In addition, as a support for the developing roller 220, a manifold 400 for ejecting and supplying the developer to the developing gap G formed between the developing roller 220 and the photosensitive belt 110 is provided.

The developing roller 220 is located in a tray 260 that collects the developing solution after development and supplies it to a working solution tank (not shown), which can be lifted and lowered below the photosensitive belt 110. do.

The developing tank 210 is supported and installed on a developing roller 220 which is raised and lowered to store the developing solution which is finally supplied to the developing gap and finally recovered, and to be discharged into the tray 260. In addition, in the developing tank 210, a spiral brush roller 270 is installed to clean the residual developer remaining on the surface of the developing roller 220 in contact with a lower side of the developing roller 220. In addition, a cleaning blade 280 is installed between the developing roller 220 and the brush roller 270 so as to contact and clean them simultaneously.

Above the tray 260 is provided with a primary squeeze roller 240 for compressing the excessive developer developed on the photosensitive belt 110 to film the toner in the developer and squeeze most of the carriers other than the filmed toner. do. Reference numeral 240a denotes a first blade 240a installed to scrape the developer squeezed by the primary squeeze roller 240 so that the developer may enter the tray 260. Further, although not shown in the drawing, the secondary squeeze roller (not shown) and the second to squeeze the developer remaining in the photosensitive belt 110 even after the squeezing operation by the primary squeeze roller 240 It is also possible to install two blades (not shown) together.

The manifold 400 which characterizes the present invention is formed in the casing member 430 so that the developing roller 220 is rotatably supported, and connected to a predetermined developer supply path (not shown). And a developing solution inlet 410 for introducing a developer supplied by a supply pump (not shown) and the casing member 430 to communicate with the developing solution inlet 410. It is provided with an ink ejecting portion 420 for ejecting the developer flowed through the outer peripheral surface of the developing roller 220.

Here, the casing member 430 is different from the conventional "V" for guiding the developer to flow into the developing tank 210 by blocking the developer from overflowing in the opposite direction to the position of the developing roller 220 so as not to overflow. It has a slanted portion 430a having a gentle shape rather than a shape having a groove. Here, the manifold 400 is usually made of a plastic or metal material, and is manufactured by an injection molding method.

On the other hand, the casing member 430 of the manifold 400 is overflowed to one side of the casing member 430 flows along the body of the developer is splashed into the peripheral device, such as a laser scanning unit (13 in Figure 1) Guide plate 450 for blocking is further provided. Here, the developing solution blocked in the guide plate 450 should be installed to fall into the tray 260.

The operation of the developing unit of the wet electrophotographic printer according to the above configuration will be described in detail.

In the developing operation, the developing roller 220 positioned in the tray 260 is supported by a plurality of rollers 102 by a separate lifting means (not shown) to be raised below the photosensitive belt 110 for traveling in an endless track. When the developing roller 220 is raised, the developing tank 210 having the brush roller 270 therein is also supported by the developing roller 220 and raised to the set with the developing roller 220.

Thereafter, when the developing roller 220 reaches a position maintaining the developing gap with the photosensitive belt 210, the developer supplied by the supply pump (not shown) is the developer inlet 410 of the manifold 40. After flowing into the casing member 430 through the developer, it is supplied to the developing gap between the developing roller 220 and the photosensitive belt 110 through the developer ejecting part 420.

At this time, if a part of the developer supplied is overflowed to the rear of the casing member 430, since the body shape of the casing member 430 is gentle, the developer is rearward along the inclined portion 430a, that is, the developer roller ( 220) in the opposite direction to the position. As shown by the arrow in FIG. 3, the developer falling back as described above is not accumulated on the body of the casing member 430, but flows down the inclined portion 430a into the tray 260.

If the developer supplied to the developing gap is excessively overflowed, the developer may not flow down into the tray 260 by taking the inclined portion 430a of the casing member 430 and fall to the rear of the tray 260.

At this time, the developer that is passed to the rear of the tray 260 is blocked by the body of the guide plate 450, the developer blocked by the body of the guide plate 450 is guided into the tray 260 and falls. Therefore, it is possible to prevent the overflowed developer from contaminating the peripheral device disposed behind the casing member 430, in particular, the laser scanning unit (13 of FIG. 1).

As described above, the developing solution supplied to the developing gap adheres to the outer circumferential surface of the developing roller 220 having a predetermined voltage. In this way, the developing solution remaining on the outer circumference of the developing roller 220 is first removed by the brush roller 270 which is in contact with the developing roller 220 and rotates in the same direction as the developing roller 220. The brush roller 270 has a brush formed on the outer circumferential surface of the brush helical to improve the cleaning efficiency by removing the developer in one direction. Then, the developer remaining without being removed by the brush roller 270 is removed again by the cleaning blade 280 whose one end is in contact with the outer circumferential surface of the developing roller 220. Here, the cleaning blade 280 is in contact with the developing roller 220 and the brush roller 270 at the same time to allow the brush roller 270 to clean the developer attached to the cleaning blade 280 body. The developer thus removed is collected and stored in the developing tank 210.

On the other hand, after the completion of development, the developing roller 220 supported by the developing tank 210 is lowered into the tray 260. When the developing roller 220 is lowered in this way, the developing solution in the developing tank 210 is discharged and collected into the tray 260 and supplied to a working solution tank (not shown).

As described above, the developing unit of the wet electrophotographic printing press according to the present invention improves the shape of the manifold so that the developer does not accumulate in the body, and the laser scanning unit even if the excessive developer overflows. Since it is blocked to fall to a peripheral device such as, as a result, there is an advantage in that the printing state is kept clear by preventing contamination of the peripheral device.

Claims (1)

A developing roller for raising and lowering the developing solution in the electrostatic latent image area of the photosensitive belt which is supported by a plurality of rollers and travels on an endless track, and is supported by the developing roller, and is supported between the developing roller and the photosensitive belt. In the developing unit of a wet electrophotographic printing press having a manifold for ejecting the developing solution into a developing gap formed in the The manifold includes a casing member, and the casing member is provided with an inclined portion having a gentle shape so that the developer, which overflows in a direction opposite to the developing roller, flows down the body without accumulation. The developing unit of the wet electrophotographic printing machine, characterized in that the guide plate is further provided to block the overflow of the developing solution to the peripheral device.