JPH0128517Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a liquid developing device for an electrostatic printer.
In particular, it is aimed at an apparatus that prevents pulsation of the liquid supply on the developing surface and obtains image quality without unevenness in density.

Hereinafter, the present invention will be explained based on the drawings.

FIG. 1 is a plan configuration diagram showing an example of a conventional liquid developing device for an electrostatic printer, and only the tank portion is shown as a side view for convenience. FIG. 2 is an enlarged sectional view taken along the line .about. in FIG. 1. FIG.

The recording configuration and recording process of a conventional electrostatic printer will be explained with reference to FIGS. 1 and 2. A line-shaped electrode head 2 and a developing body 3 are arranged adjacent to each other on the lower surface, that is, the recording surface, of the recording medium 1 at right angles to the feeding direction shown by arrow A.

The developing body 3 has a structure of two groove chambers, and is provided on the recording surface side of the recording medium 1. This 2
The groove chamber of the strip is composed of a liquid supply groove 4 on the front side and a suction groove 5 on the rear side, and the structure of the liquid supply groove 4 is a liquid supply hole (not shown) at one end of the groove and a liquid drainage hole at the other end. Provided respectively,
The liquid supply hole is connected to the tank 10, and the liquid drain hole is connected to the suction port of the pump 6 via pipes. As a result, the developer 7 is supplied from the tank 10 to the liquid supply groove 4 as shown by the arrow by the suction of the pump 6, since the recording medium 1 is in close contact with the upper opening of the liquid supply groove 4. In addition, the suction groove 5 has a discharge hole (not shown) in the center of the groove, and by connecting this discharge hole to the suction side of the pump 6, the developer 7 can be transferred to the liquid supply groove 4.
At the same time, the developer 7 adhering to unnecessary parts other than pixels on the recording surface of the recording medium 1 is sucked in the suction groove 5 as shown by the arrow, and the developer 7 is supplied to the tank 10.
Return to the atmosphere side of the chamber. Thereby, the developer 7 is constantly circulated through the tank 10 while contacting the recording medium 1.

Describing the recording process of the electrostatic printer configured as described above, first, when a pulsed voltage of either positive or negative is applied to the electrode head 2 for each I dot corresponding to a desired pixel, the recording medium 1 is moved from the recording surface. Since the recording medium 1 is integrally formed with three layers in the order of an insulating layer, a conductive layer, and a base paper layer, and the base paper layer is connected to the ground side, the recording surface of this recording medium 1 has a polarity corresponding to the pixel. The charge is interrupted and an electrostatic latent image is formed. Since the recording medium 1 is sequentially conveyed in the direction of arrow A, the electrostatic latent image comes into contact with the developer 7 at the liquid supply groove 4 of the developer 3. The developing solution 7 is previously given a polarity opposite to that of the latent image charge, and when it comes into contact with it, it is electrostatically attracted and becomes a visible image. At the same time, the developer 7 also adheres to unnecessary portions that do not correspond to pixels. Therefore, in the next step, the recording portion of the recording medium 1 is
When conveyed upward, the suction groove 5 is suctioned by the pump 6, so unnecessary developer 7 with no electrostatic charge is sucked away, and the electrostatically attracted pixels overcome the suction and onto the recording medium 1. It is recorded as a visible image, and in the case of a liquid development method, the developer 7 is generally absorbed into the recording medium 1 and dries quickly, so it can be completed as a recording paper without being fixed.

However, in the above-mentioned structure, since the liquid supply groove 4 in contact with the recording medium 1 is a long groove in the entire width direction, the developing liquid 7 is caused by changes in fluid pressure and turbulence near the liquid supply hole and the liquid drainage hole. Due to the pulsation of the fluid,
Since uniform contact with the recording medium 1 cannot be obtained, the image quality becomes uneven. This development is not very noticeable when expressing lines, etc., but it becomes a fatal and serious defect when expressing images.

The present invention was developed in view of the above-mentioned defects, and a porous plate made of a porous and liquid-permeable liquid suppressing material is inserted between the contact between the recording medium and the developer.
Even if there is pulsation in the developer, this porous plate prevents the pulsation and maintains a uniform state of contact with the recording surface of the recording medium, making it possible to obtain uniform image quality without shading. The aim is to provide a new device.

Hereinafter, one embodiment of the present invention will be described based on the drawings. FIG. 3 is a plan view showing an embodiment of the liquid developing device for an electrostatic printer according to the present invention, and only the tank portion is shown as a side view for convenience. FIG. 4 is an enlarged longitudinal sectional view taken along the line .about. in FIG. 3. FIG. Note that the same reference numerals as in FIGS. 1 and 2 indicate the same or corresponding parts.

In FIGS. 3 and 4, a line-shaped electrode head 2 and a developing body 3 are arranged adjacent to each other on the lower surface of the recording medium 1, that is, the recording surface thereof, at right angles to the feeding direction indicated by arrow A. The developing body 3 has a structure of two groove chambers, and is provided on the recording surface side of the recording medium 1. These two groove chambers have a liquid supply groove 4 on the front side, and a porous plate 8 which is a porous and liquid-permeable liquid suppressing material is disposed on the upper surface of the liquid supply groove 4 and is connected to the recording medium 1. do. Various methods of attaching this porous plate 8 can be considered, but for example, it may be pushed into the groove of the liquid supply groove 4 and the edge portions may be fixed with an adhesive or the like. Further, the liquid supply groove 4 is provided with a liquid supply hole at one end and a liquid drain hole at the other end, and the liquid supply hole and the tank 10 are connected by a pipe line, and the liquid drain hole and the suction side of the pump 6 are connected by a pipe line. As a result, the developer 7 is supplied from the tank 10 to the liquid supply groove 4 as shown by the arrow, since the recording medium 1 is in close contact with the upper surface opening of the liquid supply groove 4 due to the operation of the pump 6. . In addition, the suction groove 5 arranged on the rear side has a discharge hole in the center of the groove, and this discharge port is connected to the suction side of the pump 6 through a pipe line, and the recording medium 1 is recorded in the suction groove 5 simultaneously with liquid supply. The unnecessary developer 7 that is not attached to the pixels attached to the surface is sucked up and returned to the atmosphere side of the tank 10 as shown by the arrow. As a result, the developer 7 is transferred to the recording medium 1.
The water is constantly circulated through the tank 10 while in contact with the porous plate 8.

To explain the recording process of the present invention configured in this way, first, when a pulsed positive or negative charge is applied to the electrode head 2 for each I dot corresponding to a desired pixel, the recording surface of the recording medium 1 is 1st
Since it is formed in three layers similar to those explained in the figure, an electrostatic latent image is formed by being charged with charges having the polarity corresponding to the pixel. Next, when this electrostatic latent image is brought into contact with the developer 7 through the porous plate 9 in the developing body 3, since the developer 7 has previously been given a polarity opposite to that of the latent image charge, the electrostatic latent image is It is absorbed and becomes a visible image. At this time, as described above, in the conventional embodiment, the pulsation of the developer 7 caused by the turbulent flow near the liquid supply hole and the liquid drainage hole of the liquid supply groove 4 causes the recording medium to
However, in the present invention, the developer 7 does not come into direct contact with the recording medium 1 from the liquid supply groove 4, and the image quality becomes uneven. Since contact is made through the porous plate 9, even if there is pulsation due to turbulence, it is suppressed by the porous plate 9.
Since the developer 7 passing through the liquid supply groove 4 is supplied in a substantially constant amount due to capillary action, a uniform liquid supply state can be obtained to the recording surface of the recording medium 1, and uniform image quality can be obtained. It will be done.

In this way, the visible image obtained by the adhesion of the developer 7 is used in the next process, where the suction groove 5 absorbs the developer 7 adhering to unnecessary parts that are not pixels. Since the adhesion is stronger than the suction force of the pump 6, only desired pixels are recorded and image formation is completed.

Of course, it is necessary to take into account the prevention of clogging of the voids of the porous plate 9 with dust, etc., but this is due to the appropriate size of the holes in the porous plate in the design, warming up before starting, etc. This can be easily resolved. Furthermore, although the embodiments of the present invention have been described in terms of single color recording, it goes without saying that the gist of the present invention can be similarly applied even when recording in multiple colors.

As described above, the present invention has the technical effect of achieving uniformity of image quality for color and other surface images, but it also eliminates the need for structural complexity and increase in the number of parts required for uniform supply by other means. Compared to the structure mentioned above, the effect can be achieved by simply inserting a porous plate, and it is technically and economically extremely large, and its practicality is great.

[Brief explanation of the drawing]

FIG. 1 is a plan configuration diagram showing an example of a liquid developing device of a conventional electrostatic printer, and only the tank portion is shown as a side view for convenience. Figure 2 is from Figure 1.
FIG. 3 is an enlarged cross-sectional view taken along a line, and is a plan configuration diagram showing an embodiment of the liquid developing device for an electrostatic printer according to the present invention. Note that only the tank portion is shown as a side view for convenience. FIG. 4 is an enlarged longitudinal sectional view taken along the line .about. in FIG. 3. FIG. DESCRIPTION OF SYMBOLS 1...Recording medium, 2...Electrode head, 3...Developer, 4...Liquid supply groove, 5...Suction groove, 6...Pump, 7...Developer, 8...Porous plate, 10 ……tank.

Claims (1)

[Scope of utility model registration request] In a liquid developing device such as an electrostatic printer, one side of a porous liquid-permeable liquid suppressing material is brought into contact with the recording surface of the recording medium in the developing groove where the recording medium and the developer come into contact, and the other side is placed in contact with the recording surface of the recording medium. A liquid developing device for an electrostatic printer, characterized in that the device is disposed so as to be immersed in the developer.