Abstract: A method and an apparatus for developing a photosensitive lithographic plate at least one layer of which has been exposed with an image by a developer with conveying the same with the one layer facing substantially downwards, the method and apparatus being arranged in such a manner that the developer is supplied to the one layer and the thus-supplied developer is retained on the same layer.Therefore, the photosensitive lithographic plate can be developed without any necessity of being dipped in the developer.

Abstract: A light sensitive material processing apparatus for applying a finisher onto obverse and reverse surfaces of an image-exposed sheet-like, light-sensitive material while the light-sensitive material is being conveyed with one surface of the light-sensitive material facing substantially upward after the light-sensitive material has been developed, during automatic conveyance of the light-sensitive material. The apparatus includes a first processing device for applying the finisher onto the one surface of the light-sensitive material and holding the finisher in a state in which the finisher is placed on the one surface for a predetermined time so as to effect processing of the one surface; and a second processing device for applying the finisher onto another surface of the light-sensitive material and for maintaining a state of contact between the finisher and the other surface for a time substantially equal to the predetermined time so as to effect processing of the other surface.

Abstract: A photo-sensitive printing plate processing apparatus for processing a photo-sensitive printing plate upon which an image has been exposed is provided wherein, adjacent to a main developing tank where the photo-sensitive printing plate is conveyed, immersed in developing solution and developed, on either the upstream or downstream side with respect to the direction of conveyance of the photo-sensitive printing plate, an auxiliary developing tank is provided for applying developing solution to the photo-sensitive printing plate and performing auxiliary developing thereof and therefore allowing definite developing of the photo-sensitive printing plate to be achieved.

Abstract: A light-sensitive material processing apparatus for processing an image-wise exposed light-sensitive material by immersing the light-sensitive material in a processing solution while the light-sensitive material is being automatically conveyed. The apparatus includes a scraping brush constituted by a shaft and a synthetic resin-made elongated brush wound spirally around an outer periphery of the shaft. Accordingly, the light-sensitive layer of the light-sensitive material is scraped off by the scraping brush to effect processing.

Abstract: A method of and an apparatus for developing with a developer a photosensitive lithographic plate on which images have been exposed while transporting the photosensitive lithographic plate with one surface thereof facing roughly downwards. In the method and the apparatus, while the photosensitive lithographic plate coated with the developer is being transported in a transport path which accommodates a portion of the developer and which is curved in a downward projecting manner, the photosensitive lithographic plate is dipped in the accommodated developer and, at the same time, the development of the layers of the photosensitive lithographic plate is accelerated by rubbing them. Moreover, the developer in the transport path is replenished with the developer which has been applied to the photosensitive lithographic plate. Accordingly, it is not necessary to provide a developer replenishing device in the transport path.

Abstract: A method for processing an electrophotographic lithographic printing precursor comprising a photoconductive layer provided on a conductive substrate, the photoconductive layer having a toner image formed thereon by an electrophotographic process, comprising measuring electronically the area of the nonimage area to be processed, treating the precursor with a processing fluid from a processing fluid reservoir to remove the nonimage area of the photoconductive layer, and adding replenisher by automatic means in accordance with the area of the measured nonimage area.

Abstract: A waterless presensitized lithographic printing plate developing apparatus for processing a waterless presensitized lithographic printing plate on which an image has been exposed includes a developing section for developing the waterless presensitized lithographic printing plate by an aqueous developing solution containing an organic solvent. Therefore, water and an aqueous solvent can be simultaneously applied onto the waterless presensitized lithographic printing plate in this developing section so that a reduced size and shortened processing time can be achieved.

Abstract: A light-sensitive material processing apparatus for processing an imagewise exposed light-sensitive material while the light-sensitive material is being conveyed to a plurality of processing tanks accommodating a processing solution.

Abstract: A support for a lithographic plate produced by a process which comprises:mechanically roughening the surface of an aluminum plate,chemically etching about 5 to 20 g/m.sup.2 of aluminum from the surface of the plate, andapplying an alternating wave-form electric current to the plate in an acidic aqueous solution such that the quantity of electricity generated with the plate as the anode is equal to or greater than the quantity of electricity generated with the plate as the cathode, electrolysis being carried out such that the current density when the plate is the anode is not less than about 20 A/dm.sup.2 and the quantity of electricity generated with the plate as the anode is about 200 coulombs/dm.sup.2 or less.

Abstract: A photo-sensitive printing plate automatic developing apparatus for conveying a photo-sensitive printing plate upon which an image has been exposed, along a conveyor route while developing it in a developing tank, and then performing at least one of the following processes of washing, rinsing and desensitizing, is provided on the side of the developing tank from which the photo-sensitive printing plates are inserted, and is provided with a pair of insertion rollers that hold said photo-sensitive printing plate and conveys photo-sensitive printing plate downwards at an angle of 20.degree. or less to the horizontal, and a pair of squeeze rollers to squeeze the developing solution on the surface of said photo-sensitive printing plates while holding and conveying them after they have been conveyed drawings, in a state where the maximum radius of curvature of the photo-sensitive printing plate in the developing solution of said developing tank is from 200 mm to 900 mm.

Abstract: A method for supplementing a replenisher for developer which comprises developing a large number of PS plates imagewise exposed to light with a developer composed of an aqueous solution containing electrolytes in an automatic developing machine, characterized by determining an AC impedance of the developer contained in the automatic developing machine, obtaining a correction impedance from the measured impedance value and rate of replacement and supplementing a desired amount of the replenisher to the developer when the correction impedance reaches a predetermined value. This method makes it possible to maintain a desired activity of the developer even when a large number of PS plates are processed and to relax the restriction on the incorporation of optional devices such as an autofeeder into the automatic developing machine.

Abstract: Disclosed is a method for the manufacture of a lithographic printing plate where a photosensitive lithographic printing plate precursor is imagewise exposed, a determined about of a developer is supplied to the exposed surface and the developer is the disposed of. A surfactant is added to the developer so that the surface tension of the developer is about 50 dyne/cm or less at 25.degree. C. By the addition of the surfactant, a stable and economical development of an exposed plate is possible with a small amount of the surfactant-containing developer.

Abstract: A conveying type apparatus for processing light-sensitive plates provided with at least two processing baths, which comprises a roller type device for removing a processing solution from the plate processed, wherein said device comprises a pair of squeeze rollers and is disposed at the boundary between a preceding bath and an adjacent subsequent bath so as to separate the solutions in these baths from one another; and means for removing the processing solution on the roller surface. This processing apparatus is small-sized one, requires a small space to occupy and makes it possible to reduce the operation and production cost since the number of squeeze rollers required to prevent the processing solutions from causing admixing with one another due to the solutions carried over by a processed plates.

Abstract: A devleoping device for photosensitive materials, particularly, for photosensitive materials used flat printing plates, in which the consumption rate of the developing solution is significantly reduced. The developing solution is applied to the exposed surface of the heated photosensitive material and excess portions thereof quickly removed before the temperature of the photosensitive material is significantly lowered or the temperature of the developing solution significantly raised. The excess portons of the developing solution are recycled.

Abstract: This invention provides a developing method for photosensitive materials, in particlar for a positive photosensitive lithographic printing plate, which enables an efficient development with minimum consumption of the developing liquid. The developing method of the present invention comprises the steps of: conducting a preparatory development by applying a developing liquid to an exposed photosensitive layer of a photosensitive material, the developing liquid being supplied in an amount of necessary for each developing cycle; removing the developing liquid; discarding the developing liquid; and again applying a developing liquid to the photosensitive material to complete the development.

Abstract: A photosensitive material developing apparatus has a first area for supplying a developer to the exposed surface of an imagewise light-exposed photosensitive material, and a second area positioned on the downstream side of the first area in the direction in which the photosensitive material is transported, and adapted to develop the photosensitive material. The apparatus is provided with a wire bar having a wire wound on the outer peripheral portion thereof for the purpose of removing a part of the developer supplied to the exposed surface of the photosensitive material before development is practically commenced and of allowing only a predetermined amount of developer to remain on the exposed surface. The apparatus is further provided with a tray for collecting the removed developer, and a pump for delivering the collected developer to the first area so as to be reused.

Abstract: A process of preparing a lithographic support, the lithographic support produced by the process and a presensitized plate are disclosed. The process comprises chemically graining at least one surface of an aluminium plate with an aqueous solution containing chloride, fluoride or a mixture thereof and thereafter electrochemically graining the surface. The presensitized plate comprises a lithographically suitable light-sensitive coating on the lithographic support.

Abstract: A process for producing a support for planographic printing is described, which comprises electrochemically graining the surface of an aluminum plate with an electrolytic solution containing from 1,000 to 40,000 ppm of nitric acid, from 50 to 4,000 ppm of sulfuric acid group.

Abstract: A method of replenishing a developer during the development of photosensitive plates in a conveyor-type automatic developing machine connected to a replenishing device in which the dissolution of the photosensitive layer in the non-image area of a photosensitive plate is measured with a sensor. The sensor is positioned at a certain point in the developing zone of the machine, and, when the measured dissolution reaches a certain level, the replenishing device is automatically actuated to supply a predetermined amount of replenisher to the developer.

Abstract: A method of electrolytic treatment on the surface of metal web, such as may be employed to fabricate offset printing plates supports, in which the rate of consumption of graphite electrodes used with the process is remarkably reduced. A current having asymmetric positive and negative half cycles is applied between graphite electrodes disposed in a main cell. A portion of the current of the half cycle having the larger average value is applied to an auxiliary anode electrodes provided in an independent auxiliary cell separated from the graphite electrodes. The auxiliary electrode is made of an insoluble material. By making the current density for anode reaction on the surfaces of the graphite electrodes smaller than the current density for cathode reaction on the surfaces of the graphite electrodes, the consumption rate of the graphite electrodes is greatly reduced.