GB2032848A

GB2032848A - Washing device on offset printing machine

Info

Publication number: GB2032848A
Application number: GB7931888A
Authority: GB
Original assignee: Dainippon Screen Manufacturing Co Ltd
Current assignee: Dainippon Screen Manufacturing Co Ltd
Priority date: 1978-09-16
Filing date: 1979-09-14
Publication date: 1980-05-14
Also published as: DE2934268C2; CS209802B2; IT1123169B; IT7922530V0; FR2436017A1; DE2934268A1; FR2436017B1; IT7925738A0; GB2032848B

Abstract

A washing machine which washes a blanket cylinder of a printing machine is mounted in the frame (2) of the printing machine, and comprises a vessel (11) which surrounds generally two squeegee rollers (21) and a brush roller (16) which are movable towards and away from the blanket cylinder (1), and which has an upper opening which when the squeegee and brush rollers are moved towards the blanket cylinder so as to touch it conforms closely to the blanket roller so as to catch any ink or washing liquid which may be sprayed therefrom. When the brush roller (16) is contacted to the blanket cylinder (1) with the squeegee rollers (21) on its opposite sides, it is driven so that its periphery moves relative to that of the blanket cylinder with which it is in contact, so that it scrapes and brushes away the ink therefrom, while supply of washing liquid is maintained to the brush roller. <IMAGE>

Description

SPECIFICATION Washing machine This invention relates to a washing machine for a blanket roller or cylinder used in a printing machine such as a lithographic press, a lithographic proof press or the like.

In offset printing, when the ink is changed, or in order to improve the finish of the printing, often the blanket cylinder of the machine is washed.

Previously either the blanket roller has been washed by hand, or a washing roller has been turned in contact with the blanket cylinder to clean it. However, the positioning of this washing roller has been troublesome and, further, ink and washing liquid sprayed from the rollers have been splashed around the machine and the floor.

Further, the draining of the blanket cylinder has not been very good. Thus, if printing has been started immediately after washing the blanket cylinder, problems have arisen with the quality of the printing.

Therefore, the invention seeks to provide a washing machine for a blanket cylinder of a printing machine which may perform washing quickly and effectively, without causing mess, and which removes excess washing liquid from the blanket cylinder, and is easy and automatic in use.

According to the present invention, a washing machine for a blanket roller, comprises: two squeegee rollers and a brush roller, which are parallel to the blanket roller and are movable towards and away from its axis, so that they may be moved from a rest position wherein they do not contact the blanket roller to a washing position wherein they contact the blanket roller with the squeegee rollers on opposite sides of the brush roller; a washing vessel which is generally disposed around the brush roller and the squeegee rollers when they are in the washing position, and which receives substantially all liquid sprayed from these rollers, and which has an upper opening which when the brush and squeegee rollers are in the washing position conforms closely to the blanket roller; the brush roller being driven, when it is in the washing position, so that its periphery moves relative to the side of the blanket roller with which it is in contact, said periphery being fitted with a plurality of brush elements, and means for supplying the brush roller with washing liquid when it is in the washing position.

The present invention will become more fully understood from the following description of several preferred embodiments thereof, and from the accompanying drawings, in which: Fig. 1 is a longitudinal elevational cross-section of a washing machine for a blanket cylinder, according to the present invention; Fig. 2 is a perspective view of the machine shown in Fig. 1; Fig. 3 is a longitudinal crosssection of a washing brush roller in this machine; Fig. 4 shows two exploded plan views of possible brush arrangements for the roller of Fig.

3; and Fig. 5 is a view similar to Fig. 1, showing another embodiment of the present invention.

Referring now to the drawings, in which like reference numerals refer to the same or like parts in the various figures, there is shown in Figs. 1 and 2 a washing machine according to the present invention.

The reference numeral 1 denotes a blanket cylinder in a printing machine, which is not shown in its entirety in the drawings. The blanket cylinder 1 is mounted between a printing bed and an inking unit of the machine. To the frame 2 of the printing machine are mounted a plurality of cylinders 3a, which together with piston rods3b constitute a means for lifting the washing machine. The top ends of the piston rods 3b pass through holes 5 pierced in a support plate 4 and are fitted with retaining nuts 6 at their extremities.

Somewhat below the support plate 4 on the piston rods 3b are fitted stop plates 7, and between these stop plates 7 and the underside of the support plate 4 are fitted coil springs 8, which therefore bias the support plate 4 upwards.

Transverse plates 9 are fixed to the support plate 4, and side plates 10 (of which two are shown) are fixed on these transverse plates 9 by their folded-over ends 1 Oa so as to project upwards. Between these side plates 10 is fixed a washing vessel 11 whose top 12 is open, and which is formed of side wall plates 11 b, front and rear end plates 11 c, a bottom plate 11 a, and a pair of top plates 1 d which project slightly inwards from the side wall plates 11 b. A drain pipe 1 5 is provided at the lowest part of the washing vessel for draining the washing fluid, which may be water or the like.

This washing vessel 11 may thus be moved up and down by supplying the cylinder-piston devices 3 (consisting of the cylinders 3a and the piston rods 3b) with supply of hydraulic fluid under pressure.

To the end plates 11 c of the washing vessel 11 are rotatably mounted three rollers, which are all held to be parallel with the blanket cylinder: one brush roller 16 and two squeegee rollers 21 on shafts 17 and 22. The squeegee rollers 21 are on opposite sides of the brush roller 1 6, and, when the washing vessel 11 is raised by the cylinderpiston devices 3, all three of these rollers contact the underside of the blanket roller 1.

The brush roller 1 6 is provided over its surface with flexible hairs 18, which in this embodiment are set spirally, as seen in Fig. 3. However, in other possible embodiments these hairs could be set in other ways. Fig. 4 shows in exploded form both the spiral way of fitting the hairs 18 (Fig. 4a) and a way of fitting the hairs 1 8a in a wavy pattern of lines around its circumference (Fig. 4b).

The squeegee rollers 21 are adapted to support somewhat the blanket cylinder while it is being washed, and further serve to squeegee off excess washing fluid, as will be seen later.

The shaft 1 7 of the brush roller 1 6 is driven by a motor which is not shown, via a pulley 19 and an endless belt 20. The directions of rotation of the brush roller 16 and the blanket cylinder 1, while washing is taking place, are the same, as may be seen by the arrows in Fig. 1.

A pair of pipes 23 with spray openings 24 are provided as parallel to the rollers, so arranged that when fluid is supplied to them it is sprayed onto the walls 1 b of the vessel 1 These pipes 23 run generally under the squeegee rollers 21, and serve to wash off ink that is splashed onto these walls.

Further, a pipe 25 with spray holes 26 is provided for supplying washing liquid to the brush roller 1 6.

These pipes are connected to a washing liquid tank (not shown) via valves (which are not shown either).

The control of the timing of the raising and lowering of the vessel 11, the driving of the blanket roller 1 and of the brush roller 1 6, and of the supply of liquid to the pipes 23 and 25, is performed by a control means which is not shown, using limit switches, etc., in a per se conventional way. This has nothing directly to do with the present invention, and therefore detailed description will be omitted.

This washing machine operates as follows.

First the operation of the blanket cylinder is stopped, so that it is just above the brush roller 1 6, and then the washing vessel 11 is raised. When the squeegee rollers 21 and the brush roller 16 are in good contact with the blanket cylinder 1, the vessel 11 is stopped from further rising. In this position the opening in its top conforms closely to the blanket roller so that only small gaps are left between the sides of the blanket roller and the top plates 11 d. In this way escape of sprayed ink and washing fluid is minimized.Then the blanket cylinder and the brush roller 16 are rotated in the same rotational direction in contact with each other, so that the parts of their peripheries which are in contact are in relative motion, and therefore the brush hairs 18 scrape and clean the ink off the blanket roller, with the help of washing liquid 1 3 which is at the same time being supplied to the pipes 23 and 25 and is spurting out of the holes 24 and 26, falling to the bottom of the vessel 11, and being drained by the drain pipe 1 5.

When the washing is finished, the washing machine is lowered back to its out-of-deployment position by the cylinder-piston assembiies 3, the rotation of the blanket cylinder 1 and the brush roller 1 6 is stopped, and the blanket cylinder is ready for use in the normal way in the printing machine.

The action of the coil springs 8 etc. is to absorb a certain amount of slack in the operation of the cylinder-piston assemblies 3, and to cushion the shock of the impact of the washing machine on the blanket cylinder 1, and to ensure that the correct pressure is applied therebetween.

Fig. 5 shows a slightly varied embodiment. In this machine, the drain pipe 1 5 at the bottom of the vessel 11 is normally closed, and an overflow pipe 1 4 is provided at a certain level in the vessel 11 higher than the bottom of the brush roller 1 6, so that the brush roller 1 6 is always partly immersed in the washing liquid 1 3. Therefore, no spraying pipe such as 25 for supplying washing liquid to the brush roller is required in this case.

Apart from this, the function of this embodiment is the same as that of the first embodiment.

Although the invention has been shown and described with reference to some preferred embodiments thereof, however, it should not be considered as limited to these heads, or more and simple generalizations, or other detailed embodiments. Yet further variations of the form and the content of any particular embodiment could be made in it, without departing from the scope of the invention, defined by the accompanying claims.

Claims

1. A washing machine for a blanket roller, comprising: two squeegee rollers and a brush roller, which are parallel to the blanket roller and are movable towards and away from its axis, so that they may be moved from a rest position wherein they do not contact the blanket roller to a washing position wherein they contact the blanket roller with the squeegee rollers on opposite sides of the brush roller; a washing vessel which is generally disposed around the brush roller and the squeegee rollers when they are in the washing position, and which has an upper opening which when the brush and squeegee rollers are in the washing position conforms closely to the blanket roller;; the brush roller being driven, when it is in the washing position, so that its periphery moves relative to the side of the blanket roller with which it is in contact, said periphery being fitted with a plurality of brush elements, and means for supplying the brush roller with washing liquid when it is in the washing position.

2. A machine according to claim 1 , further comprising a spray pipe which supplies washing liquid to the brush roller.

3. A machine according to claim 1, wherein the vessel is adapted to store washing liquid to a certain depth, and wherein the brush roller extends to below that depth in the vessel, so that it is partly immersed in the washing liquid.

4. A machine according to any of claims 1-3, wherein the brush elements are arranged on the brush roller in spirals.

5. A machine according to any of claims 1-3, wherein the brush elements are arranged on the brush roller in wavy lines around its circumference.

6. A washing machine substantially as hereinbefore described with reference to and as illustrated in figures 1 and 2, 3 and 4a, 4b, or 5 of the accompanying drawings.