JPS6120967A - Wet developing mechanism - Google Patents

Abstract

PURPOSE:To prevent a toner from being stuck to a counter electrode member to stabilize the development processing by forming the counter electrode member constituting a wet developing mechanism into an endless belt and spraying a liquid developer to the counter electrode member with a prescribed pressure. CONSTITUTION:A developer 1 is pumped up by a developing pump 21 and is sprayed from an injection exit 14 of an injection pump 12 to the surface of the counter electrode 7. The injection nozzle 12 is supported axially by a supporting part 13, and the injection angle is so freely set that the developer 1 jetted from the injection exit 14 is sprayed efficiently to the counter electrode 7. Consequently, the toner stuck to the counter electrode member 7 during development is easily washed away by spray of the developer 1, and the best electrode effect is always obtained though development is repeated. Thus, the development processing is always stabilized to improve the reliability of picture quality.

Description

Detailed Description of the Invention [Technical Field of the Invention] The present invention relates to an electrophotographic image forming apparatus such as a copying apparatus or a plate making apparatus for forming an image on an electrophotographic photoreceptor using an electrophotographic method. Regarding a wet developing mechanism.

[Technical background of the invention and its problems]

Generally, when developing an electrostatic latent image formed by electrophotography, it is necessary to prevent background smudges in non-image areas on an electrophotographic photoreceptor and peripheral effects in image areas, and to improve image density. For such purposes, a counter electrode member made of a conductive plate or net is placed very close to the latent image forming surface of the electrophotographic photoreceptor. Connect to the potential body and drop to the reference potential,
In the reversal development method, an insulating state is created or an insulating pressure is applied during development.

However, in any developing method using a counter electrode plate, as development is repeated, toner adheres to and accumulates on the counter electrode member, preventing background smudges in non-image areas, preventing peripheral effects in image areas, and preventing the occurrence of peripheral effects in image areas. Effects on concentration etc. are reduced. In other words, if toner adhesion to the counter electrode member is left unaddressed, capri will occur in the entire developed image, a halo will occur in the developed image area, the image density will become thinner, and the image quality will deteriorate. Become.

In reality, such stains on the counter electrode member are manually cleaned using a cloth member, a brush member, etc. at the appropriate time, but sometimes the timing of the cleaning is too late or the cleaning work is too late. It is time consuming and
This poses a major problem in continuously and stably obtaining good image quality.

[Purpose of the invention]

The present invention has been made in view of the above circumstances, and
The object of the present invention is to provide a wet-type developing mechanism that can prevent toner from adhering to and accumulating on a counter electrode member, and furthermore, can perform stable developing processing.

[Summary of the invention]

In order to achieve the above object, the present invention has an endless belt-like counter electrode member constituting a wet developing mechanism, and a liquid developer is sprayed onto at least the counter electrode member at a desired pressure. It is something.

[Details of the invention]

The present invention will be described in detail below based on the drawings.

FIG. 1 shows an outline of the wet developing mechanism according to the present invention, in which (1) shows a liquid developer, (2) a developer container, and (3) a liquid developer.
) is the development tray, (4) is the electrophotographic photoreceptor that forms the electrostatic latent image, (5) is the feed roller, (6) is the aperture roller, (force is the counter electrode member, α2) is the jet Each nozzle is shown.

Counter electrode member (force is endless belt-like, drive roll (8)
It is rotatably supported by and a 7-ree roll (9). In the drawing, this opposing electrode member (the force is a motor (11) and a drive belt aO that constitute a part of the drive mechanism)
The electrophotographic photoreceptor (4) is rotated along the direction of the arrow (20) by the drive roller (8).
Specific examples of the constituent members of the incoming counter electrode member (7) that moves in the moving direction of ) include metal, conductive rubber, conductive resin, etc., but the constituent members are not limited to these. It is sufficient that it can be formed in the shape of an endless belt and that it has the level of conductivity required for a normal counter electrode member.

In addition, a counter electrode member (7) rotating in the direction of the arrow (201)
) A developing tray (3) that supports the electrophotographic photoreceptor (4) on which an electrostatic latent image is formed during development in a transportable state is disposed on the opposing portion of the lower surface. A pair of feed rollers (5), (5) and a pair of aperture rollers (6), (6) are in a state in which the electrophotographic photoreceptor (4) can be held and transported before and after this developing tray (3). It is placed in Each of these rollers is interlocked with a drive mechanism (not shown), and the electrophotographic photoreceptor (4) is conveyed from the feed roller side to the aperture roller side via the development tray (3).

On the other hand, the developer (1) is sucked up from inside the developer container (2) by the developer pump (21), is sent to the spray nozzle (12+) by the developer pipe (221, and is sent from the counter electrode member (force After being sprayed onto the surface at a desired pressure, the developer flows between the counter electrode member (7) and the developer tray (3), and then falls into the developer container (2) and is collected.

The injection nozzle Q2+ is pivotally supported on the nozzle support part Q31,
It can be rotated around this point, and the ejection angle can be freely set so that the liquid developer (1) ejected from the ejection port α can be efficiently sprayed onto the counter electrode member (7). . Therefore, toner that has resistant to force on the counter electrode member during development is easily washed away by spraying the liquid developer (1), and even if development is repeated, the best electrode effect can always be obtained. Therefore, the image quality of the developed image on the electrophotographic photoreceptor (4) is equally good at both the initial stage and the final stage of development.

FIG. 2 shows another embodiment of the present invention, in which toner on the counter electrode member (7) that has adhered during development can also be removed by doctor blades (151, (151')). There is no particular limitation on the installation location of the doctor blade (15) and ff51', but considering the toner scraping effect, it is recommended to install the doctor blade (15) and free roller (9).
Preferably near the installation location. Furthermore, the installation locations of the doctor blades are not limited to those shown in the drawings, and even if the drive roller (8) has a configuration in which one of the free rollers (9) is removed, six or more doctor blades may be installed. .

The material of the doctor blade is not particularly limited as long as it does not damage the counter electrode member (7); Because there are cases where the voltage is applied,
The attachment part of the doctor blade must be insulated from the body of the developing device.

On the other hand, as mentioned above, the injection nozzle (121) rotates around the nozzle support part 03), and the liquid developer ejected from the injection port 04) is sprayed onto the doctor blade (
15) and the counter electrode member (forced surface) in sequence. With this configuration, the toner adhering to the counter electrode member (7) during development is scraped off by the doctor blade (151). Not only is it washed away by the jet pressure of the liquid developer jetted out from the spout (14+), but it also washes away the toner that tends to accumulate on the tip after being scraped off with the doctor blade 0 (g). Since the particles are removed, a good developed image can always be obtained even after multiple development cycles.

Further, the timing of the rotation of the counter electrode member (7) and the spouting of the liquid (1) are not particularly limited. 6
), the rotation of the force and the jetting of the liquid developer (1) can be performed only when the counter electrode member (7) is located between the counter electrode member (7 )
The rotation of the electrophotographic photoreceptor (the force is the feeding roller (5)
It is only necessary to perform this operation only when the roller is located between the aperture roller (6) and the aperture roller (6).

Of course, the rotation of the counter electrode member (7) and the liquid developer (1
) may be ejected all the time. [Effects of the Invention] Since the present invention has the above-described configuration, the toner adhering to the counter electrode member during development is easily washed away by spraying the liquid developer and is prevented from being deposited on the counter electrode member. (
Therefore, even if development is repeated many times, the effects of the counter electrode member will not be reduced, and as a result, a good developed image will always be obtained on the electrophotographic photoreceptor.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIG. 1 is a schematic explanatory diagram of a wet developing device according to the present invention, and FIG.
The figure shows a schematic explanatory diagram of the present invention, and the figure shows a schematic explanatory diagram of another embodiment of the present invention.

Claims (3)

[Claims] (1) In a developing mechanism of an electrophotographic image forming apparatus for forming an image on an electrophotographic photoreceptor using electrophotography, the counter electrode member is in the form of an endless belt, and the driving mechanism drives the electrophotographic photoreceptor. It is rotatable along the direction of movement, and an injection nozzle is arranged near the endless belt-shaped counter electrode member, and the liquid developer is sprayed from the injection port of the injection nozzle at a desired pressure. 1. A wet type developing mechanism, wherein the liquid is sprayed onto at least the surface of the moving counter electrode member. (2) The wet developing mechanism according to claim 1, further comprising a doctor blade whose tip abuts against the rotating surface of the counter electrode member. (3) The spray nozzle rotates so that the liquid developer sprayed from the spray port is sprayed onto the opposing electrode member surface and the vicinity of the tip of the doctor blade. Wet development mechanism described.