JPS6257027B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrophotographic liquid developing device, and more particularly to a liquid jet developing device.

In electrophotography, liquid development is optimal for obtaining high-quality images with good gradation and graininess, especially high-quality color images. However, in liquid development, in order to create an image without edge effects, it is necessary to bring the developing electrode as close as possible to the latent image surface and at the same time send a large amount of developer into the narrow space between the latent image surface and the developing electrode. .

The liquid jet method is a method in which a jet of developer is forcibly sent between the developing electrode and the latent image surface, and is a suitable means for solving the above problem, and has been proposed extensively recently. Problems such as uneven developer density and white spots may occur due to the flow of the solution, and the equipment needs to be larger to prevent the large amount of developer being sprayed from scattering or going around, so improvements are required. Much remains to be done.

SUMMARY OF THE INVENTION An object of the present invention is to provide a small-sized liquid developing device that can create high-quality images at high speed. This objective was achieved by devising ways to spray the developer uniformly and by improving the flow of the solution between the developing electrode and the latent image surface, which are provided very close to each other.

The apparatus of the present invention comprises (a) a flat plate developing electrode having a developer jetting slit near the developer inlet; (b) a hollow box placed on the upper back surface of the electrode so as to cover the slit; a developing head consisting of a developing solution supply tube whose tip end is housed inside; and (c) a number of developing heads disposed close to each other below the electrode, excluding the position facing the slit and the vicinity thereof. The main component is a support plate for a latent image carrier sheet having liquid flow holes, and the developer supply pipe supplies a developer almost evenly over the entire area of the developing head, and a plurality of developer tubes are provided at positions not directly facing the slits. It is characterized by having a liquid outlet.

The details of the apparatus of the present invention will be explained below based on the drawings.

FIG. 1 is a perspective view schematically showing the main parts of an example of the developing device of the present invention. In the figure, a hollow box 1 serving as the outer wall of the developing head is integrated with a developing electrode 2 and the tip of a developer supply tube 10 to constitute the developing head. The cross section of the hollow box 1 may be rectangular, semicircular, or semielliptical as long as it is large enough to accommodate the supply pipe 10. Below the developing electrode 2,
A latent image carrier sheet support 3 is arranged parallel to the latent image carrier sheet, usually at a distance of about 0.1 to 1 mm from each other. The carrier sheet 5 having the electrostatic latent image on its upper surface is conveyed over the support plate 3 in the direction of the arrow by the conveyance roller 4 or an alternative conveyance means, and passes through the development area between the development electrode 2 and the support plate 3. , carried out by similar rollers. The developer is sent from a separately provided tank to the supply pipe 10 by a pump, rectified by the development head, and supplied to the development area. The used developer is collected through the holes or side edges of the support plate.

2 is a perspective view illustrating the inside of the developing head of the apparatus shown in FIG. 1. FIG. The distal end 6 of the developer supply tube 10 has a plurality of holes 7 and is closed at the end so as to supply a substantially uniform amount of solution to the entire area within the developing head. The liquid ejected from the hole 7 fills the developing head and flows through the slit 8 formed in the developing electrode 2.
From there, it becomes a uniform band-shaped flow and is ejected to the developing area below.

FIG. 3 is a perspective view of the latent image carrier sheet support plate 3 of the apparatus shown in FIG. Guide part 1 for feeding the latent image carrier sheet, except for the part where the developer ejected from the slit collides when placed opposite to the development electrode.
1 and a large number of holes 12 in a portion forward of the developer jet collision position in the sheet traveling direction.

FIG. 4 is a schematic cross-sectional view showing an example of the main parts near the developing head and developing area of the apparatus of the present invention. The hole 7 provided in the tip 6 housed in the developing head of the developer supply tube does not directly face the slit 8, but rather allows the liquid to flow out toward the wall of the hollow box 1 or the part of the electrode 2 other than the slit perforation. It is arranged so that The developer once fills the developing head and is ejected downward from the slit 8 in a uniform flow with no unevenness in flow rate or flow rate. A latent image carrier sheet supporting plate is provided very close to and parallel to the developing electrode 2, and since it has a large number of holes 12 except under the slit 8, the liquid flows smoothly, as indicated by diagonal lines in the figure. The developing area below the slit shown is filled with the liquid, making it possible to avoid entrapment of air bubbles and uneven development of the liquid. Therefore, when the latent image carrier sheet 5 passes, a large amount of developer comes into contact with its surface instantly, causing insufficient initial development, uneven development density, and edge effects.
The occurrence of white spots can be completely prevented.

FIG. 5 is a schematic cross-sectional view showing another example of the developing head of the apparatus of the present invention, in which the shape of the inner wall of the hollow box and the relationship between it and the slit position have been improved. FIG. 6 is a cross-sectional view showing one embodiment of the holes in the latent image carrier sheet support plate of the apparatus of the present invention, and the holes 8 are inclined in the direction of movement of the latent image carrier sheet.
It has a hole in it. The inclination angle θ of the hole is generally
The angle is between 30° and 90°.

As can be seen from the above explanation, the device of the present invention has the following features:
Because the development electrode is placed very close to the latent image surface and development is carried out in a uniform flow of developer, there is no possibility of insufficient initial development or
High-quality images can be obtained by eliminating density unevenness. Furthermore, since a large amount of developer is brought into contact with the method, development can be done in a short time, high-speed processing is possible, and the device itself can be made smaller.

[Brief explanation of the drawing]

1 is a perspective view schematically showing the main parts of an example of the developing device of the present invention, FIG. 2 is a perspective view showing the inside of the developing head of the device shown in FIG. 1, and FIG. 3 is a perspective view showing the inside of the developing head of the device shown in FIG. FIG. 4 is a schematic cross-sectional view illustrating the outline of the main parts; FIG. 5 is a schematic cross-sectional view showing another example of the developing head; FIG. 6 is a schematic cross-sectional view showing the latent image carrier sheet supporting plate It is a sectional view showing one aspect of a hole. In the figure, 2 is a developing electrode, 3 is a latent image carrier sheet support plate, 5 is a latent image carrier sheet, and 6 is a latent image carrier sheet support plate.

Claims (1)

[Claims] 1. (a) A flat plate developing electrode having a developer jetting slit near the entrance of the developing area, (b) A hollow box placed on the upper back surface of the electrode to cover the slit, and a tip thereof inside the hollow box. and (c) a developing head consisting of a developer supply pipe in which a developer is stored, and (c) a developing head that is disposed close to the bottom of the electrode and has a large number of developer flow holes except for the position facing the slit and the vicinity thereof. The main component is a latent image carrier sheet support plate,
An electrophotographic liquid, characterized in that the developer supply pipe supplies the developer almost evenly over the entire area of the developing head, and has a plurality of developer outlet ports at positions not directly facing the slit. Developing device.