JPH06130821A - Wet electrophotographic developing device - Google Patents

Abstract

PURPOSE:To provide a wet electrophotographic developing device where the turbulence of toner flow on an electrophotographic printing plate passing through a developing gap formed by a developing electrode plate and a back surface electrode plate is restrained and irregularity by fogging is not caused in a non-image part as a developing device which performs development by allowing toner liquid and the electrophotographic printing plate to pass through the developing gap. CONSTITUTION:The purpose is accomplished by attaching a flow straightening plate 11 having a smooth slope inclining downward to the lower surface of the discharge port 5 of a toner supply device supplying the toner liquid to the developing gap. Or the purpose is accomplished by setting the discharge port 5 on an upstream side by 10-50mm apart from the developing electrode plate 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a direct power supply type wet developing apparatus used in an electrophotographic plate making machine.

[0002]

2. Description of the Related Art A wet type developing device of a direct power feeding type used in electrophotographic platemaking has a structure as shown in FIG. In the figure, the electrophotographic printing plate 1 on which the electrostatic latent image is formed is sent to the developing section by the carrying roll 2.
A back electrode plate 3 is provided at a predetermined angle in the developing section, and a development electrode plate 4 is provided above the back electrode plate 3 with a development gap at a predetermined interval so as to face the back electrode plate 3. Has been. Further, a toner liquid supply device 6 having a slit-shaped discharge port 5 is provided at the entrance of the developing gap,
The toner liquid is discharged from the discharge port 5 and supplied into the developing gap. Then, the electrophotographic printing plate 1 sent by the transport roll 2 is developed while passing through the developing gap together with the toner liquid, and the excess toner liquid is removed by a squeeze roll 7 provided near the outlet of the developing gap and is carried out. It has become so.

[0003]

When a halftone image is made by using the developing device having such a structure, the toner flow on the electrophotographic printing plate 1 is disturbed in the developing gap, causing fog unevenness in the non-image area. There is a problem that a uniform image cannot be reproduced.

The present invention has been made under the circumstances described above, and an object of the present invention is to allow a toner liquid and an electrophotographic printing plate to pass through a developing gap formed by a developing electrode plate and a back electrode plate. It is an object of the present invention to provide a wet electrophotographic developing device that suppresses the disturbance of the toner flow on the master passing through the developing gap and does not cause fog unevenness in the non-image area in the developing device for developing.

[0005]

As a result of various studies on the cause of the turbulence of the toner flow generated in the developing gap, the inventors of the present invention have found that the turbulent flow generated at the downflow point of the toner flow upstream of the developing gap inlet causes the above-mentioned toner It was discovered that a turbulent flow would occur. It was found that the generation of the turbulent flow is mainly related to the shape of the flow of the toner liquid ejected from the ejection port and the distance between the ejection port and the developing electrode plate.

From the above, the above object of the present invention can be achieved by mounting a straightening plate having a smooth slope inclined downward on the lower surface of the discharge port of the toner liquid supply device. Alternatively, it can also be achieved by installing the discharge port upstream from the developing electrode plate by 10 mm to 50 mm.

[0007]

The toner liquid discharged from the discharge port flows down along the smooth rectifying plate inclined downward and reaches the upper surface of the electrophotographic printing plate, so that no turbulent flow is generated. Further, the toner liquid flowing down by separating the discharge port from the end of the developing electrode is rectified by the time it reaches the developing gap inlet, and does not affect the toner flow in the developing gap.

[0008]

EXAMPLE FIG. 4 shows the structure of a conventional toner liquid supply device, which has a slit-shaped discharge port 5 at the bottom and a support 8
It is fixedly supported on. A distribution pipe 9 for distributing the toner liquid is provided in the toner liquid supply device 6, and a plurality of holes are formed in a straight line in the length direction on the pipe wall to distribute the toner liquid in the toner liquid supply device 6. Then, the liquid is discharged from the discharge port 5. Then, the discharged toner liquid is disturbed by a step formed by the bottom plate 10 of the toner liquid supply device 6 and the end portion of the support member 8 and irregularly drops on the upper surface of the electrophotographic printing plate 1 to generate a turbulent flow. Become.

FIG. 1 is a diagram for explaining the structure of the current plate of the present invention. A rectifying plate 11 is attached to the bottom plate 10 of the toner liquid supply device 6 as shown in the figure, and its end face forms an inclined face with the end face of the bottom plate 10 at an acute angle with respect to the transport surface of the electrophotographic printing plate 1. By doing so, there is no step in the flow path of the discharged liquid, the toner liquid is smoothly supplied in the traveling direction of the electrophotographic printing plate 1, and turbulent flow does not occur at the downflow point.

FIG. 2 is a sectional view showing the structure of an embodiment of the toner liquid supply device according to the present invention. A cough plate 12 is provided inside the toner liquid supply device 6 so as to partition the interior with a vertical wall having a gap above. The right side of the weir plate 12 in the figure forms a reservoir for the liquid including the distribution pipe 9, and the toner liquid is always stored up to the upper edge of the weir plate 12. Again cough 12
The left side forms a rectifying portion, and the toner liquid that has passed through the gap above the weir plate 12 is regulated in flow and discharged from the discharge port 5.
The toner liquid thus discharged forms a uniform flow over the entire width of the discharge port.

FIG. 3 is a cross-sectional view for explaining the operation of the installation position of the toner liquid supply device. It is assumed that the ejection port 5 of the toner liquid supply device 6 is installed upstream from the developing electrode 4 by a distance d. Here, if the distance d is too small, the influence of the turbulent flow generated at the point where the toner liquid flows down reaches the developing gap to cause the fog unevenness as described above. However, if the distance d is 10 mm or more, this problem occurs. Will be resolved. However, if d is made larger than necessary, irregular development will start before the development performed in the development gap, resulting in defective development. From the result of the experiment, the appropriate value of the distance d was in the range of 10 mm to 50 mm.

The above-mentioned means become more effective by using them in combination.

[0013]

As described above, according to the wet electrophotographic developing apparatus of the present invention, by suppressing the turbulent flow generated at the toner liquid flow-down point which is the cause of the turbulent toner flow in the developing gap. In addition, it is possible to prevent fog unevenness in the non-image area during plate making of a halftone image.

[Brief description of drawings]

FIG. 1 is a diagram for explaining the structure of a current plate in the present invention.

FIG. 2 is a sectional view showing the structure of an embodiment of the toner liquid supply device according to the present invention.

FIG. 3 is a diagram for explaining the operation of the installation position of the toner supplier.

FIG. 4 is a diagram showing a structure of a conventional toner liquid supply device.

FIG. 5 is a cross-sectional view showing a schematic structure of a conventional wet type electrophotographic developing apparatus by a direct power feeding method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electrophotographic printing plate 2 Conveying roll 3 Rear electrode plate 4 Developing electrode plate 5 Discharge port 6 Toner liquid supply device 7 Squeezing roll 8 Support 9 min pipe 10 Bottom plate 11 Rectifying plate 12 Weir plate

Claims (4)

[Claims] 1. A developing device for developing by passing a toner liquid and an electrophotographic printing plate through a developing gap formed by a developing electrode plate and a back electrode plate, and supplying a toner liquid to the developing gap. A wet electrophotographic developing device, characterized in that a flow straightening plate having a slope inclined downward is attached to the lower surface of the discharge port of the container. 2. The wet electrophotographic developing apparatus according to claim 1, wherein a dam plate is provided inside the toner supplier to form a liquid storage portion and a rectifying portion. 3. A developing device for developing by allowing a toner liquid and an electrophotographic printing plate to pass through a developing gap formed by a developing electrode plate and a back electrode plate and supplying the toner liquid into the developing gap. A wet electrophotographic developing apparatus, characterized in that the discharge port of the feeder is installed upstream from the developing electrode plate by 10 mm to 50 mm. 4. A developing device for developing by passing a toner liquid and an electrophotographic printing plate through a developing gap formed by a developing electrode plate and a back electrode plate, and supplying a toner liquid to the developing gap. A straightening plate with a slope that slopes downward is attached to the lower surface of the discharge port of the vessel,
A wet electrophotographic developing device, characterized in that the discharge port is arranged upstream from the developing electrode plate by 10 mm to 50 mm.