JPH01185569A - Liquid developing device - Google Patents

Abstract

PURPOSE:To enable development using plural colors and to make the device compact by connecting a vacuum pump, developer tanks, and a cleaning liquid tank through a 2nd selector valve. CONSTITUTION:A single development head 2 is provided which has one or plural developer supply grooves 3 forming a developer chamber closed by con tact of a recording medium with the surface. One end of the developer supply groove of this development head 2 is connected to developer tanks 6a...6d and a cleaning liquid tank 7 through a 1st selector valve 5, the vacuum pump 11 is connected to the other end of the developer supply groove 3, and the vacuum pump 11, developer tanks 6a...6d, and cleaning liquid tank 7 are connected through the 2nd selector valve 12. Consequently, the compact device is constitut ed only by arranging the single development head 2, and the 1st and 2nd selector valves 5 and 12 are switched to enable development using optional colors.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a liquid developing device for applying a developer to a recording medium to develop an electrostatic latent image on the recording medium.

Conventional technology In conventional color electrostatic recording devices, a recording head and a developing device were provided for each color such as black, cyan, magenta, yellow, etc., and they were arranged in parallel along the conveyance path of the recording medium. This requires space, resulting in a large and expensive device.

Therefore, a color isoelectric recording apparatus has been proposed in which one recording head and a plurality of developing devices for each color are provided, and the recording medium is returned and conveyed after recording of each color is completed (for example, Japanese Patent Laid-Open No. 59-105660 (see official bulletin).

A configuration example of such a color electrostatic recording device ff120 is shown in the second example.
To explain with reference to the figure and FIG. 3, 21 is electrostatic recording paper;
Reference numeral 2 denotes one multi-needle electrode recording head arranged so as to face the conveyance path of the electrostatic recording paper, and 23a to 23d designate development heads also arranged so as to face the conveyance path. Supplied. Each developing head 23a to 23
As shown in FIG. 3, each of d has a plurality of straight developer supply grooves 24 with open tops, one end of which is connected to developer tanks 25a to 25d, and the other end connected to a vacuum pump 26a. ~26d, and the developer sucked by this vacuum pump is transferred to developer tanks 25a~25d.
being swept away. A squeeze nozzle 27 suctions and removes the solvent of the developer added to the electrostatic recording paper 1 and fixes it, and is connected to a waste liquid tank 29 via a vacuum pump 28 .

30 is e? 4 a presser roller for maintaining contact between the recording paper 21 and the recording pad 22; 31 a developer concentration detector; 32
3 is a high-concentration developer replenishment tank for replenishing toner, and 33 is an electromagnetic valve that is turned on according to the concentration detected by the concentration detector 31. 34 is a vacuum switch.

Further, each of the developing heads 23a to 23d is configured to be movable between a position facing the fine feed path and a position retracted downward.

When recording on the recording medium 21, the recording head 22 is operated with a developing head for a developer of an arbitrary color, for example, the developing head 23a, placed in the transport path, and a vacuum pump corresponding to the developing head 23a is operated. 26a and the vacuum pump 28 of the squeeze nozzle 27 are operated to move the recording medium. Then, the recording head 22 prints e on the recording medium 21.
':r1 latent image is formed, developed by the developing head 23a, and fixed by the squeeze nozzle 27.

Next, after retracting the developing head 23a so that it does not come into contact with the recording medium 21, the recording medium 21 is returned to its original position and transported, and then the operation of forming an image of the next color in the same manner as above is repeated. By this, a predetermined color image is formed.

Problem to be Solved by the Invention However, in the above configuration, the plurality of developing heads of the developing device are arranged in parallel along the conveyance path of the recording medium, which requires a large space and cannot be configured compactly. There was a problem.

SUMMARY OF THE INVENTION In view of the above-mentioned problem α, an object of the present invention is to provide a liquid developing device that is capable of developing multiple colors with a single developing head and can be configured compactly.

Another object of the present invention is to provide a liquid developing device in which no developer remains in the developer supply groove when the developer is discharged from the developing head.

Means for Solving the Problems In order to achieve the above-mentioned object, the liquid developing device of the present invention has a single unit having one or more developer supply grooves forming a closed developer chamber with the recording medium in contact with the surface thereof. A developing head is provided, and one end of the developer supply groove of this developing head is connected to a first
Connected to a plurality of developer tanks and cleaning solution tanks via switching valves, and connected to the developer supply groove! A vacuum pump is connected to the end thereof, and the vacuum pump is connected to the developer tank and the cleaning liquid tank via a second switching valve. Further, it is preferable to arrange a filter for capturing F-ner between the @2 switching valve and the cleaning liquid tank.

Further, in the developing head, a footing layer made of a material having poor wettability with the developer is formed on the surface of the developer supply groove.

Effects According to the above configuration, it is possible to have a compact configuration because only a single developing head is provided, and development of any color is possible by switching the PJl and the second switching valve. Sometimes, by cleaning the developer supply groove and the commonly used developer supply path with a cleaning liquid, the colors before and after the developer are not mixed. Also,
If toner particles are collected before the cleaning liquid after cleaning is returned to the cleaning liquid tank, staining can be prevented even when the cleaning liquid is circulated.

In addition, by forming a coating layer made of a material with poor machinability such as polytetrafluoroethylene on the surface of the developer supply groove of the development head, the developer is kept in the developer supply groove when the developer is discharged. It is possible to prevent residual waste, and it can be suitably applied to a liquid developing device equipped with a single developing head as described above.

EXAMPLE Hereinafter, an example of the present invention will be described with reference to FIG.

The overall configuration of the color electrostatic recording apparatus 20 is the same as that described as the conventional example in FIG. 2, except for the developing device, and the description thereof will be referred to and the description thereof will be omitted here.

In FIG. 1, 1 is a liquid developing device, and 2 is a developing head thereof, which is disposed at the bottom of a recording medium conveyance path. The developing head 2 has a plurality of developer supply grooves 3 (three in the illustrated example) open on the upper surface thereof, which are formed along the longitudinal direction of the head. A coating layer made of a material having poor wettability with the developer, such as polytetrafluoroethylene, is formed on the surface of the developer supply groove 3 . Both ends of these developer supply grooves 3 are communicated with connection ports 4a and 4b formed at both ends of the developing head 2, respectively.

The connection port 4a on one end side of the developing rod 2 is connected to a first switching valve 5.
The inlet of this first switching valve 5 is connected to the outlet of
Developing solution tanks 6a to 6d of different colors, such as plastic, cyan, magenta, and yellow, and supply pipes 8a to 8e opening in the cleaning solution tank 7 are connected. Further, this first switching valve 5 is also provided with an atmosphere opening port 9. The eight ports are configured such that any of the inlets can selectively communicate with the atmosphere opening port 9.

On the other hand, the connection port 4b on the other end side of the developing head 2 is connected to the vacuum sensor 10. It is connected to the inlet of the second switching valve 12 via the vacuum pump 11, and the outlet of the second switching valve 12 is connected to the discharge pipe 1.
The developing solution tanks 6a to 6d and the cleaning solution tank 7 are communicated via 3a to 13e.

14 is a valve drive motor that switches the two first and second switching valves 5.12. In addition, the second switching valve 12 and the cleaning liquid tank 7
A filter 15 for collecting toner particles is interposed in the discharge pipe 13e between the two.

In the above configuration, a developer tank containing a developer of a color to be recorded first when recording on a recording medium, for example, a developer tank 6a1: a connected supply pipe 8a and a discharge pipe 13;
a to the connection port 4a41 of the developing head 2, and the vacuum pump 1
Drive 1. Then, when the recording medium comes into contact with the opening of the developer supply groove 3 and the open opening is pinched, the vacuum pump 11 creates a negative pressure in the developer supply groove 3, and the developer is discharged from the developer tank 6a. This developer supply groove 3 is sucked up.
A portion of the toner in the developer adheres to the electrostatic latent image portion of the recording medium to perform development, and the remaining developer is sucked and circulated.

After the development of the above color is completed, when developing with a different color, first open the first switching valve 5 to the atmosphere opening 9 while the recording medium is returned to its original position, and the developer is The developer in the supply groove 3 is discharged. At this time, since the surface of the developer supply groove 3 is coated with a material with poor wettability, very little developer remains attached to the surface.

Next, the first and second switching valves 5.12 are switched to connect the cleaning liquid tank 7 to circulate the cleaning liquid, thereby cleaning the inside of the developer supply groove 3. At this time as well, the coating layer allows for easy and quick cleaning. Furthermore, since toner particles are removed by the filter 15 before the cleaning liquid flows back into the cleaning liquid tank 7, no dirt is generated even when the cleaning liquid is circulated.

Thereafter, by opening the first switching valve 5 to the atmosphere opening 9, the cleaning liquid is allowed to wander in the developer supply groove 3 and the supply passage.

A supply pipe 8b and 1 connected to a developer tank, for example developer tank 6b, containing a developer of another color to be recorded.
The same operation as above is carried out by switching the first and second switching valves 5.12 so as to communicate the discharge pipe 13b with the connection ports 4a, 4b of the developer rad 2. Thereafter, by repeating the same operation for the remaining colors, a desired color image can be recorded on the recording medium.

Note that even in other systems, such as the conventional liquid developing device shown in FIG. 2, great effects can be obtained by forming a coating layer on the surface of the developer supply groove of the developing head.

Effects of the Invention According to the liquid developing device of the present invention, it is only necessary to dispose a single developing head as described above, resulting in a compact structure, and by switching the first and second switching valves, it is possible to It is possible to develop the following colors, and furthermore, since the developer supply groove and the shared developer supply passage are cleaned with the cleaning liquid at the time of switching, the colors before and after are not mixed. In addition, by collecting toner particles before the cleaning liquid flows back into the cleaning liquid tank after cleaning, it is possible to prevent the toner particles from becoming dirty even when the cleaning liquid is circulated. By forming a coating layer made of a material with poor properties, great effects can be achieved, such as preventing the developer from remaining in the developer supply groove when the developer is discharged.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of an embodiment of the present invention, and FIG. 2 is a perspective view showing the schematic configuration of a conventional color EI recording device.
FIG. 3 is a perspective view of the developing head. 1・・・・・・・・・・・・・・・・・・・・・Liquid developing device 2・・・・・・・・・・・・・・・・・・・・・
Developing head 3・・・・・・・・・・・・・・・・・・
・・Developer supply groove 5・・・・・・・・・・・・・・・・
...First switching valve 6a to 6d...Developer tank 7...
・・Cleaning liquid tank 11・・・・・・・・・・・・・・・
・・・・・・Vacuum pump 12・・・・・・・・・・・・
......Second switching valve 15...
············filter.

Claims (4)

[Claims] (1) A single developing head having one or more developer supply grooves forming a closed developer chamber with the recording medium in contact with the surface, one end of the developer supply groove of this development head being connected to a first developer supply groove.
A vacuum pump is connected to the other end of the developer supply groove, and the vacuum pump and the developer tank and the cleaning solution tank are connected to a plurality of developer tanks and cleaning fluid tanks via a switching valve. A liquid developing device characterized in that the device is connected via a liquid developing device. (2) The liquid developing device according to claim 1, wherein a coating layer made of a material having poor wettability with the developer is formed on the surface of the developer supply groove. (3) The liquid developing device according to claim 1 or 2, wherein a filter for collecting toner is disposed between the second switching valve and the cleaning liquid tank. (4) A developing head having one or more developer supply grooves forming a closed developer chamber with the recording medium in contact with the surface, one end of the developer supply groove being a developer tank, and the other end being a vacuum pump. A liquid developing device connected to the developer tank via a liquid developing device, characterized in that a coating layer made of a material having poor wettability with the developer is formed on the surface of the developer supply groove.