GB2056373A - Device for adjusting an inking assembly - Google Patents

Abstract

A device for adjusting an inking assembly for a rotary printing machine of the offset type comprises an assembly of sliding pushers 6, returned by springs 13, controlled by respective eccentrics 12 and acting by their mobile ends on a flexible blade 3 controlling the flow of ink. Each eccentric 6 is constituted by a cylinder in which is made an eccentric circular groove receiving in its bottom the end of the pusher pushed by its return spring. The various cylinders are housed in a common groove made in the front face of the support and in which they are maintained in position vertically between the upper and lower sides of the groove, whilst being spaced apart from the bottom of this groove by the pushers. A plate 18 closing the groove towards the outside i.e. on the front face side, is in abutment on each cylinder to define the position of the eccentric groove borne by the cylinder in the horizontal direction. The plates 18 may also be adjustable in position as at 25 to further aid adjustment. <IMAGE>

Description

SPECIFICATION Device for adjusting an inking assembly The present invention relates to a device for adjusting an inking assembly for a printing machine of the offset type.

The inking assemblies of offset printing machines generally comprise a support having an upper face which is inclined with respect to the horizontal and on which are fixed a continuous flexible blade or a plurality of parallel, adjacent flexible blades. Parallel to this inking assembly support there extends a roller of horizontal and transverse axis and the lower end of the or each flexible blade which is free is located in the immediate vicinity of this inking roller. A mass of ink is permanently contained in the space defined by the lower part of the flexible blade and the inking roller. Furthermore, means are provided for individually adjusting at different points the position of the lower edge of the flexible blade with respect to the inking roller so as to adjust, correlatively, the flow of ink passing between the lower edge of the blade and the inking roller.

The means for adjusting the flexible blade of the inking assembly are constituted, in a known device, by mobile pushers mounted to slide in the inking assembly support and, for each pusher, by an eccentric mounted to rotate in the support about an axis parallel to that of the inking roller.

With each pusher are also associated a spring constantly applying the pusher against the associated accentric and a level projecting outwardly and enabling each eccentric to rotate so as to adjust the longitudinal position of the pusher and consequently that of the lower end of the flexible blade with respect to the inking roller.

Each lever for adjusting an eccentric and a pusher associated therewith moves in front of a graduation indicating the adjustment of the flexible blade.

Such an adjusting device is described for example in German Patent Application No.

25 50720 published before examination.

Heretofore known adjusting devices comprising pushers have the drawback of being relatively complex as they use individual mechanisms comprising a plurality of parts for supporting the various eccentrics in rotation. Furthermore, the calibration of the various pushers cannot be effected easily.

It is essentially an object of the present invention to remedy these drawbacks by providing an adjusting device in which the eccentrics controlling the pushers are assembled in particularly simple manner and the calibration of each pusher may be effected more easily.

To this end, this device for adjusting an inking assembly for a rotary printing machine of the offset type comprising at least one flexible blade, inclined with respect to the horizontal, whose upper part is fixed to a support and whose lower end is located near an inking roller of horizontal axis so as to define, between this roller and the blade, a volume containing a reserve of ink, and means for individually adjusting the position of the lower end of the or each flexible blade, so as correlatively to adjust the flow of ink passing between the lower end and the inking roller, these means comprising, below the blade, mobile pushers mounted to slide in the support of the inking assembly and, for each pusher, an eccentric mounted to rotate in the support about an axis parallel to that of the roller of the inking assembly, a spring for constantly applying the pusher against the eccentric and a lever fast with this eccentric to cause it to rotate so as to adjust the longitudinal position of the pusher and consequently that of the lower end of the flexible blade with respect to the inking roller, is characterised in that each eccentric is constituted by a cylinder in which is made an eccentric circular groove receiving, in its bottom, the end of the pusher pushed by its return spring, the various cylinders are housed in a common groove made in the front face of the support and in which they are maintained in position vertically between the upper and lower sides of the groove, whilst being spaced apart from the bottom of this groove by the pushers urged by the springs, and a plate closing the groove towards the outside, i.e. towards the front face side, is in abutment on each cylinder to define the position of the eccentric groove carried by the cylinder in the horizontal direction.

According to a further feature of the invention, the plate holding each cylinder forming an eccentric in position is engaged, in its upper part, in another groove in the inking assembly support in which it is held between an elastic member housed in a recess provided on the inner side of the groove, and a calibration screw provided on the outer side of this groove, this calibration screw being screwed in a tapped hole opening in the upper front face of the inking assembly support.

The device according to the invention offers the advantage that the various eccentrics controlling the pushers are positioned and maintained in position very simply. Furthermore, it is very easy to effect the calibration of each pusher by acting on the calibration screw accessible on the front face of the inking assembly support.

The invention will be more readily understood on reading the following description with reference to the accompanying drawings, in which: Figure 1 is a view in verticai and transverse section of a device for adjusting an inking assembly of an offset printing machine, according to the invention.

Figure 2 is a view in partial elevation of the device of Figure 1 , taken from the left of Figure 1.

Figure 3 is a view in section along the line Ill-Ill of Figure 1.

Figure 4 is a side view of the ends of two adjacent pushers located beneath the flexible blade.

Referring now to the drawings, Figures 1 and 2 show an inking arrangement of a rotary printing machine of the offset type, this inking arrangement comprising a support 1 having an upper face 2 inclined with respect to the horizontal. A blade 3 is applied on this upper face 2. This blade 3 is fixed, in its upper part, to the face 2 of the support 1 and its lower edge 3a is, on the other hand, movable. This edge 3a is located in the immediate vicinity of an inking roller 4 whose horizontal axis extends perpendicularly to the plane of the Figure and parallel to the support 1. The flexible blade 3 defines, in its lower part, with the inking roller 4, a volume in which an ink reserve 5 is constituted.The inking roller 4 is driven in rotation in the direction of the arrow in Figure 1 i.e. in anti-clockwise direction and it takes with it, on its surface, opposite the flexible blade 3, a film of ink which is laminated between the roller 4 and the edge 3a of the blade, the thickness of the film of ink thus laminated being a function of the position of the blade 3a. The thickness of this film of ink is adjusted along the roller 4, as a function of the subject to be printed.

The adjustment of the position of the edge 3a of the blade 3, at different points spaced apart longitudinally, is effected by means of the adjusting device according to the invention. This device comprises, at each point of adjustment, a pusher 6 which is constituted by a rod of circular section and which is mounted to move in translation in a housing 7 extending in a plane perpendicularly to the axis of the support 1 and the roller 4. This housing 7 is preferably inclined with respect to the horizontal, downwardly in the direction of the roller 4, as shown in Figure 1.

Consequently, the angle between the pusher 6 and the flexible blade 3 which it controls may be much smaller than the one between an adjusting screw and the blade 3 in the case of prior known adjusting devices. One of the ends 6a of the pusher 6 which is near the inking roller 4, is located beneath the lower end part of the blade 3 and is in contact with this blade, virtually under its lower edge 3a. This end 6a preferably has a horizontal and transverse flat portion 6c extending along a chord, as may be seen in Figure 4, in order to have a linear and non-punctual contact with the flexible blade 3. The other end 6b of the pusher 6, located at a level higher than the preceding one, is in abutment against an eccentric 8 mounted in a groove 9 provided in the front face 1 a of the support 1 of the inking assembly.All the eccentrics 8 controlling the respective pushers 6 are aligned in the same horizontal plane.

According to the invention, each eccentric 8 is constituted by a cylinder 11 which is machined a circular groove 12 eccentric with respect to the axis of the cylinder 11. The pusher 6 is maintained in abutment, by its end 6b, against the bottom of the groove 12, under the action of a spring 13.

The end 6b of the pusher is narrower and forms a lug blocked laterally in the groove 12, this preventing the pusher 6 from rotating about its axis. The spring 13 may be constituted for example by a compression spring (cup spring) disposed in a chamber 14 in the support 1 extending the housing 7 of the pusher 6 on the front side. This spring 13 abuts on the one hand in the bottom of the chamber 14 and on the other hand against a collar 1 5 fast with the pusher 6, and it maintains the cylinder 11, via the pusher 6, remote from the bottom of the groove 9.

The position of the cylinder 11 of the eccentric 8 is defined vertically by its holding between the two upper and lower (9a and 9b respectively) sides of the groove 9 which is machined in the inking assembly support 1. This position is defined horizontally by the end 6b of the pusher 6 engaged in the groove 12 and by the abutment of this cylinder 11 against a plate 1 8 closing the groove 9 outwardly, i.e. on the front face 1 a side.

This plate 1 8 whose position is adjustable, is maintained, in its lower part, by a heel 19 which is made in the inking assembly support 1 and which defines, on the outer side, a groove 21 in which is engaged the lower part of the plate 1 8. This heel 1 9 materialises an axis of rotation for the plate 18, this axis being parallel to that of the inking roller 4 and of the support 1. The upper part of the adjustable plate 18 is engaged in a groove 22 of the inking assembly support and it is maintained in this groove between an elastic ring 23 housed in a V-sectioned groove provided on the inner side of the groove 22 and a calibration screw 24 provided on the outer side, this calibration screw 24 being screwed in a tapped hole 25 opening in the upper front face 1 b of the support.

The adjusting device according to the invention comprises as many adjustable plates as there are eccentrics 8 and consequently points of adjustment. A space 26 (Figure 2) is, however, arranged between two successive plates 1 8 in order to allow passage of a lever 27 fixed to one end of the cylinder 11 in which the eccentric groove 12 is made. This level is fixed, at one of its ends, to the front face of the cylinder 11 and its other end, which projects to the rear of the inking assembly, allows the adjustment by its vertical displacement producing the rotation of the eccentric 8.

The angle of rotation of the eccentric 8 is sufficiently small (about 600) for the displacement of the pusher 6 resulting therefrom to vary approximately proportionally to that of the end of the lever which thus forms a slide moving along a graduation (not shown) made on the front face of the inking assembly. The length of the lever 27 is chosen so that this graduation is sufficiently expanded to be visible. The amplitude of the movement is defined by the offset of the cylinder 11 with respect to its circular groove 12. The sensitivity most adapted to an easy handing may thus be defined by experience.

The device according to the invention makes it possible to have, at a given instant, a clear image of the adjustment of a point or a zone of the inking assembly, by the position in height of the different levers 27 forming slides, hence a good solution to the problem of display.

The calibration screw 24 renders the graduation significant by compensating the defects provoked by wear and tear and by variations in dimensions due to the dismantlings and assemblings for maintenance purposes or to the change of parts (particularly flexible blades).

By way of example, calibration may be effected as follows: 1 - all the levers forming slides 27 set at zero (inking assembly totally closed) 2 -- adjustment of each calibration screw 24 to be at the limit of total wiping of the inking assembly.

Each position of a slide 27 then corresponds to a reproducible value of the flow of ink at the point in question. This reproducibility of the adjustment enables the inking times to be accelerated. In fact, when new work is set on the offset printing machine, it is possible to preadjust the inking assembly either by displaying the positions of the slides 27 noted during a preceding execution of this work, or by studying and calculating the ink consumptions of the subject to be printed. This second case corresponds to preparatory phase of the work which is carried out outside the printing machine.

Claims (4)

1. In a device for adjusting an inking assembly for a rotary printing machine of the offset type, comprising at least one flexible blade, inclined with respect to the horizontal, whose upper part is fixed to a support and whose lower end is located near an inking roller of horizontal axis so as to define, between this roller and the blade, a volume containing a reserve of ink, and means for individually adjusting the position of the lower end of the or each flexible blade so as correlatively to adjust the flow of ink passing between the lower end and the inking roller, these means comprising below the blade, mobile pushers mounted to slide in the support of the inking assembly and, for each pusher, an eccentric mounted to rotate in the support about an axis parallel to that of the roller of the inking assembly, a spring for constantly applying the pusher against the eccentric and a lever fast with this eccentric to cause it to rotate so as to adjust the longitudinal position of the pusher and consequently that of the lower end of the flexible blade with respect to the inking roller, each eccentric is constituted by a cylinder in which is made an eccentric circular groove, receiving, in its bottom, the end of the pusher pushed by its return spring, the various cylinders are housed in a common groove made in the front face of the support and in which they are maintained in position vertically between the upper and lower sides of the groove, whilst being .spaced apart from the bottom of this groove by the pushers urged by the spring, and a plate closing the groove towards the outside, i.e. on the front face side, is in abutment on each cylinder to define the position of the eccentric groove carried by the cylinder in the horizontal direction.

2. The adjusting device of Claim 1, wherein the plate holding each cylinder forming an eccentric in position, is engaged in its lower part in a horizontal groove defined on the outer side by a heel on which the plate abuts and materialising an axis of rotation for this plate, and the latter is engaged, in its upper part, in another groove in the inking assembly support in which it is maintained between an elastic member housed in a recess provided on the inner side of the groove and a calibration screw provided on the outer side of this groove, this calibration screw being screwed in a tapped hole opening in the upper front face of the inking assembly support.

3. The adjusting device of Claim 1, wherein spaces are arranged between the successive plates holding the eccentrics in place and, through these spaces, the levers fixed respectively to the ends of the cylinders of the eccentrics project outwardly, these levers forming slides moving along the graduations made on the front face of the inking assembly.

4. A device for adjusting an inking assembly for a rotary printing machine of the offset type substantially as hereinbefore described with reference to, and as illustrated by the accompanying drawings.