JP2716893B2 - Wet electrophotographic developing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wet electrophotographic developing apparatus for performing a wet developing process on a photosensitive material in a developing step of an electrophotographic plate making machine.

[0002]

2. Description of the Related Art As shown in FIG. 3, a conventional wet electrophotographic developing apparatus uses a charged and exposed electrophotographic photosensitive material (hereinafter referred to as a master) while flowing a developing solution from a nozzle 2 between two electrode plates 1. 3) The developing solution is passed through and the used developer is returned to the toner tank 4 at the bottom, and is sent again to the nozzle 2 by the pump 5 to circulate. The master 3 is conveyed in the developing unit 6 by a conveying roller 7 for guiding from the photographing unit into the developing unit 6 and a squeeze roller 8 for squeezing and removing excess developer adhering to the developed master. It is sent to the fixing section of the process.

One problem with such a wet electrophotographic developing device is that the concentration of the developing solution changes greatly between continuous plate making and intermittent plate making due to the evaporation of the toner solvent in the developing solution. In some cases, stable quality could not be obtained over a long period of time. In addition, the toner solvent in the developing solution attached to the developing electrode or the roller may evaporate and dry to lower the developing efficiency, or the toner adhered to the master may be peeled off and adhered to the master, causing printing stains.
It was necessary to wash the entire developing section.

[0004]

In order to prevent the above-mentioned evaporation of the developing solution, as shown in FIG.
It is sufficient to cover the whole with a sealing system, but the entrance and exit of the master 3 require openings 10 and 11 and cannot be completely sealed. In particular, the squeeze roller 8 facing the opening 10 is the easiest to dry, the toner adheres, and the plate surface is stained, and the maintenance becomes difficult.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a wet electrophotographic developing apparatus capable of preventing a problem caused by drying of a squeeze roller.

[0006]

SUMMARY OF THE INVENTION The present invention relates to a wet electrophotographic developing device in an electrophotographic plate making machine,
The above object of the present invention, together with the entire development unit covered with a cover leaving doorway of an electrophotographic photosensitive material, said cover
A squeeze roller provided facing the outlet side opening
Liquid electrophotographic developing device for the perforated plate is provided, the developer falling from the electrode plates and to make the evaporation <br/> presentation surface and reservoir by a predetermined amount into the perforated inner plate having a lower vicinity of the small hole of Achieved by Also, even if a liquid reservoir is provided instead of a perforated plate,
Equivalent objectives are achieved.

[0007]

The developer, which has fallen from the electrode plate to the perforated plate, is stored in the perforated plate in a fixed amount by the balance between the outflow action by gravity and the passage resistance due to the hole diameter of the perforated plate to form an evaporation surface, and the inside of the cover is formed. To suppress the drying of the squeeze roller.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional structural view of one embodiment of the wet electrophotographic developing apparatus of the present invention. Note that the same reference numerals are given to the same structural portions as those in the related art, and the description thereof is omitted. FIG. 1 shows a developing device having a conventional structure in which an upper portion of a developing unit 6 is covered with a cover 9 and a perforated plate 12 is provided near a lower portion of a squeeze roller 8 across a circulation path of a developer. With such a configuration, as a result of maintaining the amount of the developer in the perforated plate determined by the pore diameter of the perforated plate and the viscosity of the liquid,
The vapor pressure in the cover 9 increases due to the toner solvent evaporating from the surface.

For the perforated plate, a punching metal having small holes with a hole diameter of about 1 mmΦ is used. If the hole diameter is 2 mmΦ or more, all the developer passes, and if the hole diameter is too small, the resistance increases and the passage of the liquid is hindered. Therefore, a hole diameter of about 1 mmΦ is optimal. Instead of punching metal, a foam or cloth having open cells such as sponge can be used as the perforated plate.

FIG. 2 shows another embodiment of the present invention. In this embodiment, instead of a perforated plate, a liquid pool 13 is provided below the squeeze roller 8 as an evaporation surface of the developer for increasing the vapor pressure in the cover 9. That is, the developer dropped from the electrode plate 1 is received by the liquid reservoir 13, overflows when the amount of the liquid reaches a fixed amount, and circulates to the toner tank 4. In this case, drying of the squeeze roller 8 is suppressed by evaporation of the toner solvent from the developer surface in the liquid pool.

[0011]

As described above, by covering the developing section with the cover and forming an evaporating surface of the developing solution in the vicinity of the squeeze roller, the drying prevention period of 1 to 1.5 days when only the shield is used is 2-3. It has become possible to extend it to five days. Also, since it is only necessary to place a perforated plate, the apparatus is very simple, and can be easily removed and cleaned.

[Brief description of the drawings]

FIG. 1 is a sectional structural view of one embodiment of a wet electrophotographic developing device of the present invention.

FIG. 2 is a sectional structural view showing another embodiment of the present invention.

FIG. 3 is a sectional structural view showing a conventional wet electrophotographic apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electrode plate 2 Nozzle 3 Master 4 Toner tank 5 Pump 6 Developing part 7 Conveying roller 8 Squeeze roller 9 Cover 10 Opening 11 Opening 12 Perforated plate 13 Liquid pool

Claims (2)

(57) [Claims] 1. A developing process in the electrophotographic plate making machine, the entire developing unit is covered with a cover leaving doorway of an electrophotographic photosensitive material, said outlet opening in said cover
A perforated plate is provided in the vicinity of the lower portion of the squeeze roller provided to face the developer, and the developer falling from between the electrode plates is supplied into the perforated plate .
A wet-type electrophotographic developing device wherein a fixed amount is stored to form an evaporation surface. 2. The developing process in an electrophotographic plate making machine.
And leave the whole of the developing section
Cover with the cover and the outlet side opening in the cover
A liquid reservoir is provided in the vicinity of the lower portion of the squeeze roller provided so as to face the developer, and the developer that falls from between the electrode plates is placed in the liquid reservoir.
A wet-type electrophotographic developing device wherein a fixed amount is stored to form an evaporation surface .