Device for cleaning a cylinder of a printing machine

Abstract: A device for cleaning a cylinder of a printing machine of the type which uses a cleaning cloth (2) stretched between a cloth supply roll (4) and a cloth take-up roll (6) and adapted to be brought into contact with the outer periphery of a cylinder (10) in a printing machine by pressurizing means (8), the cleaning cloth (2) being impregnated with a cleaning liquid before it is set in the device. Needing no cleaning liquid supply system or liquid supply control means, the device can be realized in a very simple and compact form, which allows for easy maintenance.

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a device for cleaning the outer peripheral surface of a cylinder in a printing machine such as the blanket cylinder of an offset press or the plate cylinder of a gravure press, and in particular, to a compact and simplified device for cleaning a cylinder of a printing machine which includes no mechanism for supplying cleaning liquid to a cleaning cloth employed. 2. Description of the Prior Art In a conventional device for cleaning a cylinder of a printing machine of the type which uses a cleaning cloth, the cleaning cloth is wound around a cloth supply roll, and is continuously or intermittently taken up by a cloth take-up roll. A pressure pad serving as pressurizing means is provided between these rolls. In cleaning a cylinder such as a blanket cylinder, this pressure pad is pressed against the cylinder to wipe its surface. Simultaneously, a cleaning liquid conveyed through a header and a spray bar is supplied to the cleaning cloth, the supply of liquid being timed to start somewhat earlier than the pressing of the cloth against the cylinder. The above-described conventional cylinder cleaning device for the printing machine requires complicated control means for measuring the amount of liquid to be supplied and controlling the liquid supply timing. In addition, a relatively large space has to be secured to enable a cleaning liquid tank, etc. to be installed therein, resulting overall in a rather expensive device. US-A-4 135 448 already shows a device as described above. From FR 2 072 485 it is known to wind a cloth impregnated with ink and a cloth impregnated with dampening liquid onto a printing cylinder to provide for ink and dampening liquid instead of using conventional inking and dampening rollers. SUMMARY OF THE INVENTION It is accordingly an object of this invention to provide a cylinder cleaning device for a printing machine which includes no mechanism for supplying cleaning liquid to a cleaning cloth. In accordance with this invention, the above object can be attained by using a device as set forth in claim 1. The cleaning cloth consists of a woven fabric or a non-woven fabric made from a synthetic resin, natural fibers or wood pulp, etc. The cleaning cloth may be a composite material consisting of at least two materials selected from among synthetic resin, natural fibers and wood pulp, etc. In any case, the cleaning liquid with which the cleaning cloth is impregnated may, for example, be a mixture consisting of ca. 90% by volume of diethylene glycol and ca. 10% by volume of polyethylene glycol. In order to prevent any transpiration of the cleaning liquid, the entire back surface of a cleaning cloth impregnated with cleaning liquid is laminated with a very thin film which is impermeable to air, and said supply roll is equipped with flanges covering the end faces of the cleaning cloth coil wound on said supply roll so that cleaning liquid can evaporate neither through the circumferential nor the end surface of the coil. Thus, this invention employs a cleaning cloth which is impregnated with a cleaning liquid before it is set in the cleaning device, so that it is not necessary to provide a cleaning liquid supply system in the device, which eliminates the need for a control means and the space for accommodating it. Accordingly, a substantial reduction in cost can be attained. Transpiration of the cleaning liquid can additionally be prevented by lodging the cleaning cloth impregnated therewith in a case so that it can be supplied in a cassette form; the case supports the cloth supply roll at its ends and has an opening which is sealed before use but which serves in use as a slit through which the cleaning cloth is pulled. The objects, advantages and novel features of this invention will be described below in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a side sectional view of an embodiment of the device of this invention for cleaning a cylinder of a printing machine; Fig. 2 is a sectional view as observed in the axial direction of an embodiment of a cleaning cloth lodged in a cylindrical case so as to be supplied in a cassette form; Fig. 3 is a side sectional view of the embodiment shown in Fig. 2; Fig. 4 is a side sectional view of an embodiment wherein the cleaning cloth is lodged in a square case; Fig. 5 is a side sectional view of a supply roll showing that the cleaning cloth is laminated with a very thin film which is impermeable to air; and Fig. 6 is a perspective view of a conventional device for cleaning a cylinder. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of this invention will now be described with reference to Figs. 1 to 5. As shown in Figs. 1 to 3, a cleaning cloth 2 may be lodged in a cylindrical case 20, which is attached to the printing machine in the form of a cassette. The case 20 includes a slit 22 which may be closed airtightly by a seal (not shown) before use and which in use adapted to allow the cleaning cloth to be pulled out. Provided at the ends of the case 20 are covers 24. A cloth supply roll 4 is disposed within the case 20 with its ends passing through the covers 24 which serve as the bearings thereof through the intermediary of seals 26. In contrast to the conventional device shown in Fig. 6, the embodiment shown in Fig. 1 has no header 12 or spray bar 14, as the cleaning cloth is impregnated with cleaning liquid before it is set into the device. Neither does it require any complicated control means for measuring flow rate and controlling the liquid supply timing, which means has been indispensable in prior art cleaning devices. Furthermore, the relatively large space needed in the prior art for installing a cleaning liquid tank, etc. is no longer necessary. Accordingly, a substantial reduction in cost can be expected. The cross-sectional configuration of the case is not limited to the circular one illustrated. It can be square or polygonal, as shown in Fig. 4. An angular cross-sectional configuration is advantageous in that the slit 22 can be accurately positioned with respect to the cylinder 10 without any need for a special cutout or the like. The loss of cleaning liquid from the cleaning cloth through transpiration is on the one hand prevented by laminating its entire back surface with a very thin film 30 which is impermeable to air before it is wound around the cloth supply roll 4; any transpiration of the cleaning liquid from the edges of the strip of cleaning cloth 2 is prevented by providing flanges on the cloth supply roll 4. It may be mentioned that the cloth supply roll 4 in the embodiments shown in Figs. 3 to 5 can, of course, be made hollow. The material of the cleaning cloth 2 is preferably a non-woven fabric made from a synthetic resin or wood pulp, or a composite material of a synthetic resin and wood pulp. The cleaning liquid with which the cleaning cloth is impregnated may consist of a mixture of ca. 90% by volume of diethylene glycol and ca. 10% by volume of polyethylene glycol. All of the above-described embodiments provide a cylinder cleaning device with a simplified structure. In addition, the amount of cleaning liquid remaining in the tank does not have to be taken into account, which lessens the burden imposed on operators during both operation and maintenance. Thus, in accordance with this invention, the cleaning cloth is impregnated with a cleaning liquid before it is set in the cleaning device, so that no cleaning liquid supply system has to be provided in the device. This eliminates the need for a control means or the space that would be needed for accommodating such a system. In addition, the cleaning cloth impregnated with a cleaning liquid may be lodged in a cylindrical case for supply in a cassette form, and is laminated with a very thin film which is impermeable to air, thereby preventing any transpiration of the cleaning liquid and facilitating handling of the cleaning cloth, and additionally the cloth coil end faces are covered by end flanges to prevent cleaning liquid evaporating through the edges of the cloth.

Claims: A device for cleaning a cylinder of a printing machine of the type which has a cleaning cloth supply roll (4), a cleaning cloth take-up roll (6), a strip of cleaning cloth (2) stretched between said cleaning cloth supply roll and said cleaning cloth take-up roll, wherein a cleaning liquid is applied to said cleaning cloth, and means for pressing (8) said cleaning cloth against the outer periphery of a cylinder (10) of a printing machine, characterized in that said cleaning cloth (2) is impregnated with said cleaning liquid wherein the entire back surface of said strip of cleaning cloth (2) is laminated with a very thin film (30) which is impermeable to air, and said supply roll (4) is equipped with flanges covering the end faces of the cleaning cloth coil wound on said supply roll (4). A device as claimed in claim 1, wherein said cleaning cloth (2) consists of a woven fabric made from a synthetic resin, natural fibers, or wood pulp. A device as claimed in claim 1, wherein said cleaning cloth (2) consists of a non-woven fabric made from a synthetic resin, natural fibers, or wood pulp. A device as claimed in claim 1, wherein said cleaning cloth (2) is a composite material composed of at least two types of materials selected from among synthetic resin, natural fibers and wood pulp. A device as claimed in one of claims 1 to 4, wherein said cleaning cloth (2) is impregnated with a cleaning liquid which consists of a mixture of ca. 90% by volume of diethylene glycol and ca. 10% by volume of polyethylene glycol. A device as claimed in one of claims 1 to 5, wherein said cleaning cloth (2) is lodged in a case (20) and in use is pulled out through a slit-like opening (22) provided in said case. A device as claimed in claim 6, wherein said case (20) comprises a closed side-wall section having a slit-like opening (22) equipped with a seal to enable said cleaning cloth (2) wound around said cleaning cloth supply roll (4) to be pulled out in use, and end covers (24) having a configuration in conformity with that of said side-wall section and respective openings equipped with seals and adapted to be penetrated by the shaft of said cleaning cloth supply roll (4). A device as claimed in claim 6 or claim 7, wherein the side-wall section of said case (20) has a circular cross-sectional configuration. A device as claimed in claim 6 or claim 7, wherein the side-wall section of said case (20) has a square cross-sectional configuration. A device as claimed in claim 6 or claim 7, wherein the side-wall section of said case (20) has a polygonal cross-sectional configuration.

Inventors: HARA AKIRA, SUKIGARA MITSUNORI C O FUJI CH, TAKAGI TOSHISABURO, HARA, AKIRA, SUKIGARA, MITSUNORI C/O FUJI CHEMICALS, TAKAGI, TOSHISABURO
Applicants: B J TRADING KK, B-J TRADING LIMITED
Application year: 1989
Main classification: B41F35
IPC codes: B41F35