JPH04155357A - Wet multicolor developing device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field 1] The present invention is used in recording devices such as electrophotographic copying machines and printers, and is a wet-type recording device composed of charged particles dispersed in an insulating carrier liquid. The present invention relates to a developing device that visualizes an electrostatic latent image using a developer.

[Prior art 1] A conventional wet-type developing device is a method in which an electrostatic latent image carrier passes over a plate-shaped electrode in which developer is stored, and the developer is applied to the electrostatic latent image carrier. 62-51466 etc.) are known. In addition, the developer is discharged from a groove-shaped opening provided in the electrode plate that faces the electrostatic latent image carrier through a small gap, and responds to the electric field created by the electrostatic latent image carrier and the electrode plate. A method in which charged particles are attached and developed
4394 etc.) are known.

[Problem to be Solved by the Invention 1 In the developing devices of these developing methods, a single developing device: F! If we try to realize a multi-color developing device that sequentially uses one developer, a lot of developer will be wasted.
This had the problem of being uneconomical. That is, if the seven sets developed with the first developer are to be developed with a second developer different from these, it is necessary to remove the first developer in the developing device and replace it with the second developer. In the above-mentioned conventional technology, a large amount of the first developer remains in the developing device, and all of this is disposed of as waste liquid in a predetermined container, and the developing device is filled with the second developer, which is uneconomical. .

An object of the present invention is to solve this problem and realize a multicolor developing device in which only a small amount of developer is discarded.

Means for Solving Problems 1 The wet multicolor developing device of the present invention is a wet type multicolor developing device that develops an electrostatic latent image on an electrostatic latent image carrier with at least two types of wet developers. In the multicolor developing device, a wet developer is discharged and applied to the electrostatic latent image carrier.
a first developing section, a second developing section consisting of a conductor kept at a constant potential and facing the electrostatic latent image carrier in contact with or through a small gap; a second developing section containing a wet developer; has at least two pressure vessels maintained at a pressure higher than atmospheric pressure, the first developing section is connected to the plurality of pressure vessels, and the wet developing unit is connected to a predetermined one of the plurality of pressure vessels. The developer has a control member capable of being supplied to the developing section, and the wet developer applied to the electrostatic latent image carrier in the first developing section is applied to the electrostatic latent image in the second developing section. It is characterized in that it is configured so that it is peeled off in accordance with the conditions and the electrostatic latent image is visualized.

[Function] In the multi-color developing device of the present invention, the developer remaining in the developing device is the developer stored in the first developing section, and the amount is small, and the amount of developer remaining in the developing device is small, and the developer is discarded when switching the developer. The amount of agent can be reduced.

[Example 1 Examples of the present invention will be described.

FIG. 1 is a sectional view of an electrophotographic printer equipped with a multicolor developing device of the present invention.

A charging device 2, an exposure device 3, a multicolor developing device 4, a transfer roller 5, a peeling claw 6, a cleaning device 7, and a static eliminator 8 are arranged in this order around the photosensitive drum 1.

As shown in FIG. 3, the photosensitive drum 1, which is an electrostatic latent image carrier, has an amorphous selenium photosensitive layer 101 deposited around an aluminum tube 100. It is configured to rotate in the direction of arrow A.

The configuration of the multicolor developing device 4 is shown in FIG. Developing slit 7
A developing head 55 having a slit opening 11 facing the photosensitive drum 1 is provided. This constitutes the first developing section. The peeling roller 103 contacts the photoreceptor drum 1 through a small gap and rotates in the direction of arrow B at the same speed as the photoreceptor drum 1. This constitutes the second developing section.

The peeling blade 110 is provided with its tip abutting the peeling roller.

A wet developer is supplied to the developing head 55 in a configuration as shown in FIG. That is, it has a first supply hole 71 and a second supply hole 73 communicating with a development slit 72 filled with wet developer. The first developer container 51 is connected to the first supply hole 71 via a first control valve 53 by a pipe 63.70.

The first developer container 51 has a container 62 filled with a wet developer 56 and a high-pressure inert gas 57 . Such a developer container is disclosed in, for example, Japanese Patent Laid-Open No. 2-64587. A hollow pipe 74 with one end 75 open is
The other end 60 is closed and has a pore 61 near the closed end 60. The movable cap 59 is slidable relative to the pipe 74 and is sealed to prevent the contents of the container 62 from leaking from the sliding portion. This is the spring 58 and arrow C
is biased in the direction of When the movable cap 59 is pushed in the direction opposite to the arrow C against the force of the spring 5,
A pore 62 opened in the side surface of the movable cap 59 communicates with a pore 61 of the pipe 74, and the wet developer 56 is pushed out of the container by the internal pressure of the container 62. For purposes of explanation, the movable cap 59 shown in FIG.
The figure shows a state in which no ion is supplied. In the operating state, as shown as the second developer container 52, it is attached with the pores 61 and 62 communicating with each other.

Next, the configuration of the first control valve 53 will be explained. Movable axis 64
is biased by a spring 68, and the tip block 67 blocks the inlet side 65 and the outlet side 66.

By sliding the movable shaft 64 in the axial direction against the spring 68 using the electromagnetic bag ff169, the tip block 67 is opened and brought into an open state.

Similarly, the second developer container 52 is connected to the second supply hole 73 via the second control valve 54 .

The first developer container stores a black wet type developer, and the second developer container stores a red wet type developer.

The wet development agent is composed of toner particles made of pigment and acrylic resin dispersed together with a charge control agent and a dispersion stabilizer in a high-resistance petroleum solvent (for example, Isopar, manufactured by Esso) as a dispersion medium. There is.

A black pigment is used for the first developer, and a red pigment is used for the second developer. In this embodiment, positively charged photoreceptor drum 1
A positively charged wet developer is used so that toner particles selectively adhere to the exposed areas.

Next, the operation will be explained.

First, the image forming process will be explained. The pressure roller is placed in the depressurized position at 9'. An electrostatic latent image is formed on the photoreceptor drum 1 through a charging process and an exposure process. The static X latent image is developed using the first wet developer in the multicolor developing bag N4. That is, a black toner image is formed. The black toner image on the photosensitive drum 1 is electrostatically transferred to the transfer drum 5. Furthermore, it passes through a cleaning device 7 and a static eliminator 8, and then moves on to the charging process again.

Next, the developer switching operation described later is performed, and the second
Image formation is performed using a wet type developer, and the transfer drum 5
Two color toner images, black and red, are formed on top of each other.

The recording paper 21, which is carried out from the paper feeding device 20 that stores the recording paper 21 as a recording medium, is conveyed to the transfer area in time with the formation of the second color toner image.

Next, put the pressure roller in the pressure state shown in 9 and press it.
The color toner images are transferred all at once from the transfer drum 5 onto the recording paper 21.

After the recording paper 21 has undergone the transfer process, it is peeled off from the transfer drum 50 by the peeling claw 6, and the dispersion medium on the recording paper 21 is evaporated in the thermal fixing device 10, and the toner image is further fixed.
The paper is stored in the paper discharge tray 22.

Next, the developing operation will be explained. FIG. 3 shows the configuration of the multicolor developing device 4. The surface of the photosensitive drum 1 is uniformly charged with a positive charge, and after an exposure process, the exposed part 1.5 has a ground potential and the non-exposed part 104 has a positive potential, and enters the multicolor developing device 4. A wet developer 106 is discharged from the development slit 72 and applied onto the photoreceptor drum 1 . The peeling roller 103 is maintained at a positive potential lower than the positive potential of the non-exposed area by the power source 102. Since the layer of wet developer 1゜6 on the photoreceptor drum 1 has a positive charge, when it passes through the contact area with the peeling roller 1゜3, the layer of wet developer 1゜6 on the photoreceptor drum 1 causes the photoreceptor to be damaged in the exposed area according to the electrostatic force. Peeling roller 1 is placed in the non-exposed area toward drum 1.
Receive power towards 03. As a result, the developer layer 109 adheres to the exposed area, and the developer layer 108 in the non-exposed area 107 is transferred to the peeling roller 103.

Next, the developer switching operation will be explained.

Both the first developer container 51 and the second developer container 52 are set in an open state with the movable cap 59 pushed down. When forming an image using the first developer, the first control valve 53 is opened and the second control valve 54 is closed. Since the internal pressure of the first developer container 51 is high, the wet developer 56 fills the development slit 72 of the development head 55 through the piping 63.70 and is discharged from the opening 111, and is discharged from the photoreceptor drum 1. applied on top.

Next, when forming an image using the second developer, the first control valve 53
is closed and the second control valve 54 is opened.Similarly to the previous case, a second wet developer is supplied from the second developer container 52, fills the developer slit 72, and is discharged into the second developer container 52. The developer is applied.

The volume within the developing slit 72 is small, and only a small amount of developer is stored therein. When switching the developer, since only a small amount of the first developer remains, it can be easily pushed out and replaced with the second developer. Therefore, development can be performed in a short time after opening the second developer container. At this time, in a transient state, there is a risk that both developers will mix.
In this embodiment, the developer in this state is transferred to the developing head 5.
5 and adheres to the photoreceptor drum 1.

This adhesion area is made to correspond to the non-image area so that it adheres to the peeling roller 103 and is collected.

In this embodiment, a two-color printing apparatus has been described, but it is of course applicable to three-color and four-color printing apparatuses.

[Effect of the Invention 1 According to the present invention, the wet developer was kept at a high pressure. The electrostatic latent image carrier is supplied from a container in which the electrostatic latent image is filled, is discharged, and applied to the electrostatic latent image carrier. In contrast, in prior art methods, charged particles move electrophoretically through a carrier liquid and adhere to an electrostatic latent image carrier. In this case, in order to maintain high mobility of the developer, it is necessary to use a low-viscosity developer, and the developing section is filled with a large amount of carrier liquid. In the configuration of the present invention, the developer is directly discharged onto the electrostatic image carrier and adheres thereto, so there is no need to fill the developing section with a large amount of carrier solution. Therefore, there is no need to replace a large amount of carrier liquid when switching the developer, and it is possible to realize a multicolor developing device in which only a small amount of developer is discarded.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an electrophotographic printer equipped with a wet multicolor developing device of the present invention. FIG. 2 is a diagram showing the configuration of a wet type developer supply system of the wet type multicolor developing device of the present invention. FIG. 3 is a sectional view of the wet multicolor developing device of the present invention. 1 Photosensitive drum 4 Warm multicolor developing device 51 First developer container 52 Second developer container 53 First control valve 54 Second control valve 55 Developing head 72 Developing slit Applicant: Seiko Epson Corporation Representative Patent Attorney Kizobe Suzuki and 1 other person

Claims (1)

[Scope of Claims] A wet multicolor developing device that develops an electrostatic latent image on an electrostatic latent image carrier with at least two types of wet developer, comprising: discharging the wet developer to carry the electrostatic latent image; apply to the body,
a first developing section, a second developing section consisting of a conductor kept at a constant potential and facing the electrostatic latent image carrier in contact with or through a small gap; a second developing section containing a wet developer; has at least two pressure vessels maintained at a pressure higher than atmospheric pressure, the first developing section is connected to the plurality of pressure vessels, and the wet developing unit is connected to a predetermined one of the plurality of pressure vessels. The developer has a control member capable of being supplied to the developing section, and the wet developer applied to the electrostatic latent image carrier in the first developing section is applied to the electrostatic latent image in the second developing section. 1. A wet-type multicolor developing device characterized in that it is configured to peel off an electrostatic latent image in accordance with the conditions and visualize the electrostatic latent image.