JPH11184254A - Liquid developing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable cleaning means to surely and inexpensively clean developing units for four colors by a simple method according to respective colors by obtaining such constitution that the liquid developing units for four colors are fitted to a rotary body and at least the left liquid developing unit for one color is set at a position where it can be cleaned when the liquid developing unit for one color is set at a position where a recording medium is developed. SOLUTION: The developing units for four colors are fitted to the rotary body. Besides, a developing part and the cleaning part are arranged by being adjacent to a circumscribed circle formed in accordance with the rotation of the developing units. Then, the developing units for respective colors are stopped at the positions thereof as necessary. That means, the K cleaning part 105 is positioned in accordance with a K developing roller and the Y cleaning part 106 is positioned in accordance with a Y developing roller. Besides, the M cleaning part 103 is positioned in accordance with an M developing roller and the C cleaning part 104 is positioned in accordance with a C developing roller. At a cleaning time, the developing rollers for the respective colors are brought into contact with the respective cleaning parts and stopped so as to be cleaned.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording apparatus which performs recording by performing density gradation on a pixel-by-pixel basis, and performs faithful development with fine particle toner by using liquid development for developing an electrostatic latent image including a halftone. The present invention relates to a structure for obtaining a high-quality image by improving the reliability of the developing characteristics of each color developing device and also performing a maintenance with a simple configuration.

[0002]

2. Description of the Related Art As described in Japanese Patent Application Laid-Open No. 5-297746, a conventional apparatus forms an electrostatic latent image on a drum by an ion flow head for controlling the passage of ions, and develops the latent image. In each of the color developing units,
The color developing devices are arranged in a horizontal line, and are moved from a standby position to a developing position at the time of development, so that development of each color is performed in a plane-sequential manner.

Another conventional apparatus, as described in Japanese Patent No. 1452470, performs liquid development on an electrostatic latent image formed on a photosensitive drum, and a developing roller is made of a porous elastic material. When a part of the roller comes into contact with the developing solution, a thin film of the developing solution is formed on the developing roller by the surface tension of the developing solution and recording is performed.

Another conventional apparatus is disclosed in Japanese Patent Application Laid-Open No. 5-204252, in which a belt applicator holding a developing solution is brought close to an image holding belt on which an electrostatic latent image is formed.
The electrostatic latent image was developed.

[0005]

In the above-mentioned prior art, an electrostatic latent image is formed on a charge storage medium in the form of a drum or a belt, and when the electrostatic latent image is developed by a liquid developing device, a developing solution is used. Since the development is performed upward or sideways so as not to leak, there are restrictions such as that the developing unit cannot be lowered and the recording device cannot be tilted. Furthermore, since a stirrer and a circulating device for the developing solution were required to prevent precipitation and aggregation of the developing solution, it was not widely used.

An object of the present invention is to provide a liquid developing device for an electrostatic recording device which solves such problems.

[0007]

In order to achieve the above object, a pipe provided between a developer tank and a developing roller for applying a developer to the developing roller, or a pipe and a tank for the developer are provided. A control valve is provided at the junction, and two color liquid developing devices are arranged so that the developing surface of the developing device is 180 ° opposite, and the other two color developing devices are similarly configured. By rotating the developing device, the positional relationship with the recording medium at the time of developing each color is maintained with high accuracy.

In the cleaning of the developing roller after the development, the developing rollers are stopped at the position of the cleaning mechanism provided on the main body of the recording apparatus by rotating the developing devices of the four colors. In addition, since the cleaning unit operates for each color, the same developing roller is always located at the same cleaning unit, so that the developing roller does not mix colors.

Since the gap between the developing roller and the recording medium at the time of development needs to be 100 μm or less, the developing device is rotated and stopped at the standby position during standby, so that the developing roller and the recording medium transport mechanism are connected to each other. To prevent contact.

That is, four color developing units are attached to a rotating body,
A developing unit and a cleaning unit are provided adjacent to a circumscribed circle associated with the rotation of the developing device, and the respective color developing devices are stopped at those positions as necessary. The cleaning mechanism is linked to the developing device, and is configured such that the same cleaning unit is located on the same developing roller.

In each color developing device, the recovery of the developing solution and the sealing of the developing solution tank are performed in relation to the rotation of the developing device so that the developing solution does not leak. As a result, it is not necessary to provide the developing device with a cleaning function, so that the size can be reduced. In addition, since each of the four color developing devices rotates, each process can be selectively executed. This makes it possible to provide a highly cost-effective developing device.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will now be described with reference to FIGS.
This will be described with reference to FIG.

FIG. 1 shows an embodiment of the present invention. Recording paper 1
Into the hopper 2 and waits for a recording start command. In response to a recording start command output from the computer 23, the paper feed roller 3 rotates to start separation and feeding of the recording paper 1. Then, the recording paper 1 is conveyed with high precision by a paper feed roller 4 that holds only both ends. When the recording paper 1 is nipped by the paper feed roller 4 and reaches a recording start position (not shown), the ion flow head 5 installed near the paper feed roller generally records the first color electrostatic latent image. To start.

For example, the recording start position is set immediately after the leading end of the recording paper 1 is sandwiched between the paper feed rollers 4 and the leading end of the recording paper 1 passes through the ion flow head 5. The positioning can be performed based on the amount of paper fed from an optical reflective sensor (not shown), or by providing an optical reflective sensor near the ion flow head 5.

When the recording paper 1 is nipped by the paper feed roller 4, the recording paper 1 is released from the paper feed roller 3,
The transport load may be reduced.

Next, a configuration for forming an electrostatic latent image on the recording paper 1 will be described. The ion flow head 5 generates positive and negative ions by applying a high voltage AC to the ion source using, for example, a solid discharge electrode. next,
Only the negative ions are selectively flown on the recording paper by the first and second control electrodes having through holes to form an electrostatic latent image.

When the recording of the electrostatic latent image on the recording paper 1 is started,
For example, when recording is performed from yellow, the yellow developing roller rotates the developing unit housing 21 to define the gap with the recording paper 1 and stops at the developing position to start yellow developing. Alternatively, the guide roller 7 disposed at the developing position is slightly moved to define a gap between the developing roller and the recording paper 1 and yellow development is started. The gap between the developing roller and the recording paper 1 during development may be brought into contact with a small force, but the surface of the guide roller is made of a soft elastic layer so that it can be freely rotated so that the contact pressure is small. There is a need to.

When the leading end of the recording paper 1 is nipped by a paper feed roller A 9 that nipping only both ends of the recording paper 1, the rear end of the recording paper 1 is separated from the paper feed roller 4. When the formation and development of the electrostatic latent image are completed, the toner image on the recording paper 1 is fixed by being heated and dried by the recording paper 1 heating means, for example, the sheet heater 8.

Thereafter, the developing unit housing 21 is rotated to separate the yellow developing roller from the developing unit, and the recording paper 1 is fed in the reverse direction, and the recording paper is moved to a position where the formation of the second color electrostatic latent image is started. Convey 1. At this time, the developing roller for the second color, for example, magenta, is positioned in the developing section.

The recording paper 1 corresponds to the image signal of the second color.
The recording of, for example, a magenta electrostatic latent image on the yellow image is started in the same manner as the first color. Further, magenta development is performed in the same manner as development of the first color yellow.

Before describing the recording of the third color, the structure and operation of the developing device will be described with reference to FIG.

The developing solution and the developing roller of each color are attached to the developing unit housing 21, and the developing unit housing 21 is rotated. The yellow Y developer 63 is the Y developer cartridge 6
2 and is fixed to the developing unit housing 21.
The Y developer cartridge 62 is fixed through the Y developer inlet hole 60. At this time, the Y developer 63 is filled with the Y balls 59.
Has been dammed by

The Y developer 63 flows to the lower part of the Y developing roller 52 through the Y developer inflow hole 60 by moving the position of the Y ball 59 by rotating the Y ball cam 58. The amount of the Y developer 63 is determined by detecting the amount of the developer by the Y developer sensor 57, rotating the Y ball cam 58, and moving the position of the Y ball 59 to dam the Y developer 63 to a specified amount. Control so that

During development, the Y cover 53 is of course retracted. Next, while rotating the Y developing roller 52, the Y blade 54 is brought into contact with the Y developing roller 52,
A uniform thin film of the Y developer 63 is formed on the Y developing roller 52.

Incidentally, the Y blade 54 is fixed to a Y blade fixing plate 55, and the Y blade 54 comes into contact with the Y developing roller 52 by rotating the Y blade fixing plate 55. The Y blade fixing plate 55 has a Y scraping blade 5.
6 is also fixed, and the Y blade 54 is
2, the Y scraping blade 56 is separated from the Y developing roller 52.

On the other hand, the Y blade 54 is
The Y scraping blade 56 comes into contact with the Y developing roller 52 when it is away from the Y roller. With this structure, the Y developer 63 remaining on the Y developing roller 52 is collected by the rotation of the Y blade fixing plate 55. The figure shows a state in which Y development is being performed, and it is assumed that development immediately before Y development is K development of the previous page.

The collection of the developing solution starts when the developing unit housing 21 rotates around the rotation shaft 20 and reaches an upper position.

Here, a conventional method of cleaning the developing roller will be described with reference to FIG. After the K developing solution 69 remaining on the K developing roller 64 is roughly scraped off, cleaning is performed by the cleaner 18 provided on the K developing roller 64. In this case, in addition to the K developing roller 64, the cleaner 18
Y developing roller 52, C developing roller 74, M developing roller 7
No. 9 corresponds to this, and since each roller is cleaned at the same part, the roller becomes dirty and causes color mixing when cleaning is insufficient, which has been a major problem during development.

Thereafter, the K cover 65 is moved to the K developing roller 64.
Cover on top and take dustproof measures. On the other hand, the K developer 69
Since the K developing roller 64 is located at an upper position, the K developing roller 64 flows backward and is collected again in the K developing solution tank. The dust may be collected by a filter so that dust such as paper dust does not enter the K developer cartridge 70 at the time of backflow. When the remaining K developer 69 is collected, the K ball cam 71 is rotated, and the K ball 72 is pressed against the O-ring 84 by the K ball spring, whereby the K developer cartridge 70 is sealed. In this state, the process waits until the next development.

The method of cleaning the developing roller according to the present invention will be described with reference to FIGS. 1, 4, 5 (a) and 5 (b). The cleaning unit housing 101 is linked to the rotation shaft 20 via the cleaning unit rotation shaft 102, and the cleaning unit housing 101 is rotated by rotating the developing unit housing 21.

At this time, the K cleaning unit 105 is located corresponding to the K developing roller 64, the Y cleaning unit 106 is located corresponding to the Y developing roller 52, and the M cleaning unit 103 is located corresponding to the M developing roller 79. Position,
The C cleaning unit 104 is positioned corresponding to the C developing roller 74. At the time of cleaning, the respective color developing rollers are brought into contact with the respective cleaning sections, stopped and cleaned.

Therefore, cleaning can be performed for each color, and the developing roller can be reliably cleaned. In addition, since each cleaning unit is configured to be detachable from the cleaning unit housing 101, maintenance can be easily performed.

During standby, the developing unit housing 21 is rotated to stop the developing roller at the standby position, thereby preventing the developing roller from contacting the recording paper 1. Also,
In accordance with this, when the cleaning unit is rotated and the developing roller is in a standby state, the developing roller and the cleaning unit can be kept out of contact with each other, thereby preventing the cleaning unit from being stained. It is.

[0034]

According to the present invention, the cleaning means of the liquid developing device after development is indispensable for each color developing device.
Since the cleaning means can be surely implemented by a simple method corresponding to each color, a low-cost liquid developing device can be provided.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a liquid developing apparatus according to an embodiment of the present invention.

FIG. 2 is a structural diagram of a developing device in FIG.

FIG. 3 is a schematic configuration diagram showing a conventional liquid developing device.

FIG. 4 is a configuration diagram showing a retracted state of a cleaning unit in FIG. 1;

FIG. 5 is a configuration diagram of a cleaning unit in FIG. 1;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Recording paper, 2 ... Hopper, 3 ... Paper feed roller, 4 ... Paper feed roller, 5 ... Ion flow head, 7 ... Guide roller, 8
... Sheet heater, 9 ... Paper feed rollers A, 18 ... Cleaner, 20 ... Rotating shaft, 21 ... Developing unit housing, 22 ... Housing, 23 ... Computer, 52 ... Y developing roller, 53 ...
Y cover, 54 Y blade, 55 Y blade fixing plate, 56 Y scraping blade, 57 Y developer sensor, 58 Y ball cam, 59 Y ball, 60 Y
Developer inlet, 61 ... Y ball spring, 62 ... Y developer cartridge, 63 ... Y developer, 64 ... K developing roller, 6
5 ... K cover, 66 ... K blade, 67 ... K blade fixing plate, 68 ... K scraping blade, 69 ... K developer,
70 ... K developer cartridge, 71 ... K ball cam, 7
2 ... K ball, 73 ... K developer inlet, 74 ... C developing roller, 75 ... C ball cam, 76 ... C ball, 77 ... C
Developer cartridge 78, C developer, 79 M developing roller, 80 M ball cam, 81 M ball, 82 M
Developer 83, M developer cartridge, 84 O-ring, 101 cleaning unit housing, 102 cleaning unit rotating shaft, 103 M cleaning unit,
104: C cleaning unit, 105: K cleaning unit, 106: Y cleaning unit, 107: cleaning unit cover.

Continued on the front page (72) Inventor Kazumi Takahashi 1-1-1, Higashitaga-cho, Hitachi City, Ibaraki Prefecture Inside the Taga Headquarters, Electric Appliances Division, Hitachi, Ltd. Address Machinery Research Laboratories, Hitachi, Ltd. (72) Shogo Matsumoto 502, Kandatecho, Tsuchiura-shi, Ibaraki Prefecture Machinery Research Laboratories, Ltd. (72) 502 Akira Mori, Kartachicho, Tsuchiura-shi, Ibaraki, Japan Inside Ritsumeikan Machinery Research Laboratory

Claims (4)

[Claims] An image forming apparatus includes: means for forming an electrostatic latent image corresponding to an image signal on a recording medium; means for guiding and conveying the recording medium; and liquid developing means for developing the electrostatic latent image on the recording medium. The four color liquid developing device is attached to the rotating body, and at least the remaining one color developing device is at a position where the remaining one color developing device can be cleaned when the one color liquid developing device is at the position where the recording medium is developed. A liquid developing device characterized by the above-mentioned. 2. The liquid developing device according to claim 1, wherein
A liquid developing device, wherein a cleaning mechanism having four cleaning units is attached to a rotating body in correspondence with a liquid developing device of a color. 3. The liquid developing apparatus according to claim 1, wherein the liquid developing apparatus and the cleaning mechanism are linked to each other, and the cleaning unit rotates in accordance with each color of the liquid developing apparatus. . 4. The liquid developing device according to claim 1, wherein the cleaning mechanism is located above the liquid developing device.