JPH0580592A - Electrophotographic engraving and developing device - Google Patents

Abstract

PURPOSE:To obtain an electrophotographic engraving and developing device capable of reducing the evaporation of a developing liquid caused by the continuous ventilation of an air knife preventing irregularities in the treatment of development, to attain stable development. CONSTITUTION:The electrophotographic engraving and developing device has printing plate material detecting means 6 and 7 provided on a printing plate material carrying path in a developing process, and a blower control means 8 turning on and off a blower 9 blowing air to the air knife 5, or a change-over valve control means 10 switching the blowing of the air to the air knife 5 to an exhaust duct, and adopts a constitution so that the air knife 5 is operated only when the printing plate material passes.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic plate making / developing apparatus for developing a charged and exposed plate material in a wet development process of an electrophotographic plate making machine.

[0002]

2. Description of the Related Art As shown in FIG. 3, a conventional wet electrophotographic plate-making development apparatus develops by passing a charged and exposed plate material while flowing a developing solution from a nozzle 2 between two electrode plates 1. The developing solution used is collected in the lower tray 4 and returned to a toner tank (not shown), and is again sent to the nozzle 2 by the pump for circulation. The developed plate material is removed by the squeeze roller 3 to remove excess developer solution, but the solution is carried in from the gap between the rollers, leaving uneven wetting,
These cause uneven processing. The air knife 5 is used for preventing it, and is installed close to the squeeze roller 3, and a high-speed squeeze wind (about 15 m / sec) is applied from the air knife 5 to the plate-making material immediately after leaving the squeeze roller.
Is sprayed continuously to eliminate uneven liquid wetting.

[0003]

As described above, the development unevenness of the development can be solved by using the air knife. On the other hand, the squeeze air of the air knife flows down to the surface of the squeeze roller wetted with the liquid and the receiving tray 4. Promotes evaporation of liquid. As a result, there are problems that the squeeze roller surface is dried and the adhered toner is peeled off to stain the printing plate material, or the toner solvent is evaporated from the circulating developing solution to change the concentration and stable quality cannot be obtained. Has occurred.

The present invention has been made under the circumstances described above, and an object of the present invention is to reduce the blowing time of the squeeze air while maintaining the function of an air knife for preventing uneven processing in the development. An object of the present invention is to provide an electrophotographic plate-making development apparatus capable of performing stable development by reducing evaporation of liquid.

[0005]

SUMMARY OF THE INVENTION The present invention relates to a wet developing device in an electrophotographic plate making machine, and the above object of the present invention is to provide a plate material detecting means for detecting a plate material at a fixed point of a plate material conveying path. And a blower control means for turning on and off a blower for blowing air to the air knife based on the detection information of the printing plate material detection means, the air knife according to the length of the printing plate material to be processed. Is achieved by an electrophotographic plate-making and developing apparatus that is operated only during the time when the above-mentioned air knife passes.

[0006]

[Function] For the plate material that is intermittently conveyed at a constant speed, the plate material is developed during the operation time of the plate making machine by detecting the passage of the plate material at a fixed point and controlling the air flow by the timer. A squeeze wind is generated only during the time when the air knife is passed through.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic block diagram for explaining an embodiment of the present invention. In FIG. 1, a first plate material detection sensor 6 and a second plate material detection sensor 7 are arranged near the entrance of the developing unit described in FIG. 3 and near the air knife 5, respectively. A blower control unit 8 that operates the blower 8 based on information from the sensor is provided. When the exposed plate material is conveyed and reaches the entrance of the developing unit during the operation time of the plate making machine, the first plate material detection sensor 6 detects the leading edge of the plate material and sends a detection signal to the blower. Output to the control unit 8. The blower control unit 8 turns on the blower 9 after a lapse of a predetermined time shorter than the time when the plate material is conveyed the distance L between the first plate material detection sensor 6 and the squeeze roller 3 from the time when the leading edge is detected. .. The plate material that has completed development and has exited the squeeze roller 3 is conveyed by being squeezed by the air knife 5. When the trailing edge of the plate material passes the air knife, the second plate material detection sensor 7 detects the trailing edge. The detection signal is sent to the blower control unit 8, and the blower control unit 8 simultaneously turns off the blower 9. In this way, the air knife produces a squeeze air only for the required time.

In the above embodiment, the case where the two detection sensors are used to detect the position of the printing plate material has been described, but it is also possible to control the air blowing using one detection sensor. In other words, the first detection sensor 6 detects the leading edge and the trailing edge of the plate material passing therethrough, and outputs respective detection signals to the blower control unit 8. The blower control unit 8 turns on the blower 9 after a predetermined time shorter than the time when the plate material is conveyed the distance L from the time when the leading edge is detected, and the plate material is the first plate material when the trailing edge is detected. The same blow control can be performed by turning off the blower 9 after a predetermined time longer than the time during which the distance between the detection sensor 6 and the air knife 5 is conveyed.

In FIG. 2, the squeeze air is not generated and stopped by turning the blower on and off, but the blower is kept running and an exhaust duct is provided to let the blower blow the blower air to another place. Therefore, the air blow to the air knife is controlled. In this case, the opening / closing operation of the switching valve is performed by the command of the switching valve control unit 10 based on the detection information of the printing plate material detection sensor 6 as in the above-described embodiment. If you control the air blow to the air knife directly by turning the blower on and off, the squeeze wind will not stop immediately even if the blower switch is turned off due to the inertia of the blower and the capacity of the blower and the blower duct. Instead, it is continued until the internal pressure decreases, and when the blower is started, conversely there is a delay in the generation of swish air. Therefore, when sharp control is not possible and the cycle time of the printing plate material conveyance is short, the influence is particularly large. Control by the switching valve improves this problem.

[0010]

As described above, according to the apparatus of the present invention, the squeeze air is generated only when the plate material is passing during the operation of the plate making machine, so that the trouble caused by the evaporation of the developing solution can be reduced. be able to. As an example, the amount of toner liquid that evaporates from the surface of the squeeze roller and the pan under the developing unit due to the squeeze air is 4 when the liquid temperature is 30 ° C.
It was about ml / min. The processing time for the 1-page plate is 15 seconds / plate, and the liquid evaporation by the squeeze air during that period is 1 ml / plate.
The edition. Considering now the case of processing one page of 30 plates per hour, the evaporation amount in the apparatus of the present invention is 30 ml,
This is about 90% less than the evaporation amount of 240 ml when the squeeze air is continuously blown.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram showing another embodiment of the present invention.

FIG. 3 is a schematic configuration diagram of a conventional wet electrophotographic plate-making development apparatus.

[Explanation of symbols]

 1 Electrode Plate 2 Nozzle 3 Squeeze Roller 4 Saucepan 5 Air Knife 6 First Plate Material Detection Sensor 7 Second Plate Material Detection Sensor 8 Blower Controller 9 Blower 10 Switching Valve Controller 11 Exhaust Duct 12 Switching Valve 13 Pressure sensor

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Akihiro Kanazawa 1005 Kozono, Ayase City, Kanagawa Prefecture Fuji Micrographix Co., Ltd.

Claims (2)

[Claims] 1. A wet plate development process of an electrophotographic plate making machine, a plate material detecting means for detecting the plate material at a fixed point of a plate material conveying path, and an air squeeze means based on the detection information of the plate material detecting means. The blower that blows air to the air knife
And a blower control means for N-OFF, wherein the air knife is operated only for a time during which the plate material passes through the air knife according to the length of the plate material to be processed. Photolithography and development equipment. 2. The electrophotographic plate making apparatus according to claim 1, further comprising, instead of said blower control means, a switching valve control means for switching blower air from the blower to said exhaust duct.