Photography – Fluid-treating apparatus – Having fluid filter
Reexamination Certificate
1999-01-20
2001-06-19
Mathews, Alan A. (Department: 2851)
Photography
Fluid-treating apparatus
Having fluid filter
C396S626000, C430S399000
Reexamination Certificate
active
06247856
ABSTRACT:
FIELD OF INVENTION
The present invention relates to a system for development of photo-sensitive resin plates and apparatus used therein, which make it possible to carry out developing operation in a continuous manner over a long period of time, particularly in a process for developing photosensitive resin plates by rubbing off unexposed portions from the plates, while immersing the plates in a developing solution.
BACKGROUND OF THE INVENTION
In recent years, printing plates made of a photosensitive resin are rapidly coming into general use in various fields of printing because of their better handleability, higher productivity, lower price, and improved printing performance as compared with the conventional printing plates. There have been devised and put into practical use several processes for developing photosensitive resin plates by: (1) blowing off unexposed portions from the plates with compressed air or other means to form a relief; (2) spraying a developing solution under a constant pressure to the plates to form a relief; and (3) rubbing off unexposed portions from the plates with a brush or other means, while immersing the plates in a developing solution.
A developing solution for washing out the photosensitive resin plates in a developing process such as described in (3) above contains the dispersed resin from the unexposed portions washed off after the development. The developing solution has an increased resin content after washing out many photosensitive resin plates, causing various problems, e.g., the speed of development is decreased, and the dispersed resin is flocculated to form scum which is then adhered to the plates and the brush. Thus required are frequent disposal of the used developing solution and frequent preparation of a fresh developing solution.
To solve the above problems, some methods have been devised in which the used developing solution is recycled by removing resin components. For example, U.S. Pat. No. 5,124,736 discloses a method for filtering a developing solution in the developing unit and returning the filtrate to the developing unit for reuse as the developing solution. This method, however, is of a closed system, and the reuse of the waste developing solution as the developing solution requires once stopping the continuous development and allowing the pooled waste developing solution to stand for a long period of time (e.g., about 8 hours) so that the resin in the waste developing solution is flocculated and deposited. Thus the development and the waste disposal cannot be carried out in parallel. This method further has a defect that fine particles of resin components cannot be removed and the resin content of the developing solution is increase, lowering the speed of development.
In general, the used resin-containing developing solution has been treated for waste disposal as follows: The developing solution is transferred to another tank after the completing of development, and the resin and the developing agents contained in the developing solution, such as surfactants, are flocculated with a flocculant for making them harmless, after which the mixture is treated for separation of harmless liquids and solids by filtration or other techniques, followed separately by waste disposal. This method, however, requires suspending the developing operation for removing and treating the developing solution at the whole volume. In the case of developing machines requiring a developing solution in quantity and difficult to suspend the developing operation halfway, of which good representatives are automatic developing machines, the resin-containing developing solution is also to be treated in quantity, so that large size tanks, stirrers, and resins are need in a large scale for this treatment and it further takes a long time for suspension. Therefore, this method is not suitable for automatic developing machines.
SUMMARY OF THE INVENTION
Under these circumstances, the present inventors have intensively studied to devise a developing system and apparatus used therein, which make it possible to carry out developing operation in a continuous manner without waste disposal of a developing solution at the whole volume, without suspending the development, and without lowering the speed of development over a long period of time, thereby completing the present invention.
Thus the present invention provides a system for developing photo-sensitive resin plates with an aqueous developing solution and for treating a waste developing solution. In the system, a fresh developing solution is added to a developing unit in a continuous manner or at intervals of a fixed period, while a part of the resin-containing developing solution is removed from the developing unit, whereby the resin content of the developing solution in the developing unit is kept substantially constant and the treatment of the waste developing solution is carried out in parallel with the development.
The present invention further provides the following apparatus used in the above developing system of photosensitive resin plates.
One apparatus contains: (i) an additional developing solution tank; (ii) a developing unit; (iii) a resin flocculating unit; (iv) a solid-liquid separating unit for separating the resin and a liquid; (v) a unit for feeding a developing solution from the additional developing solution tank to a developing solution tank; and (vi) a pipe for removing a part of the developing solution from the developing tank to a waste disposal tank.
The other contains: (i) an additional developing solution tank; (ii) a developing unit; (iii) a pipe for feeding a developing solution from the additional developing solution tank to the developing unit; (iv) a concentration tank; (v) a pipe for transferring a waste developing solution from the developing unit to the concentration tank; (vi) a membrane filter module containing at least one membrane filter selected from the group consisting of reverse osmosis membrane filters, ultrafiltration membrane filters, and microfiltration membrane filters; (vii) a circulating pump for transferring the waste solution from the concentration tank to the membrane filter module; (viii) a pipe for returning a circulating waste solution discharged as a cross-flow from the membrane filter module to the concentration tank; (ix) a pipe for returning the filtrate discharged from the membrane filter module to the developing unit; (x) a valve for suspending the transfer of the developing solution, which valve is disposed on the pipe for transferring the developing solution form the developing unit to the concentration tank; (xi) a level gauge disposed in the concentration tank; (xii) a means of stopping a circulating pump when the liquid level in the concentration tank comes to a height equal to or lower than the level gauge; and (xiii) a pipe for removing the developing solution from the concentration tank.
REFERENCES:
patent: 3978506 (1976-08-01), Geyken et al.
patent: 4517282 (1985-05-01), Tomisawa et al.
patent: 4519690 (1985-05-01), Tomisawa et al.
patent: 4559295 (1985-12-01), Tomisawa et al.
patent: 4593986 (1986-06-01), Tomisawa et al.
patent: 4752283 (1988-06-01), Copeland et al.
patent: 4786417 (1988-11-01), Miki et al.
patent: 5124736 (1992-06-01), Yamamoto et al.
patent: 5321458 (1994-06-01), Shimura et al.
patent: 5759743 (1998-06-01), Muramoto et al.
patent: 5811224 (1998-09-01), Seeley et al.
patent: 5828923 (1998-10-01), Harabin et al.
patent: 3102135 (1982-08-01), None
patent: 3143106 (1983-05-01), None
patent: 3238134 (1983-05-01), None
patent: 3328264 (1984-02-01), None
patent: 0254550 (1988-01-01), None
patent: 0624828 (1994-11-01), None
patent: 0813116 (1997-12-01), None
patent: 92/22015 (1992-12-01), None
Kasho Yoshihiro
Shibano Hiroshi
Takahashi Kazuo
Leydig Voit & Mayer Ltd
Mathews Alan A.
Toyo Boseki Kabushiki Kaisha
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