EP0696503B1 - Ductor drive for feeding ink in the ductor inking device of a printing press - Google Patents

Abstract

The ink is transferred from a box (1) by a rotary roller (2) to the inking roller (4) by way of a lifting roller (3). The roller is carried by two levers (5) coupled together by a shaft (6) extending across the width of the printed sheet. The other ends of the levers are lifted by a smaller roller (7) in contact with the surface of a rotary cam (8). This roller can be displaced from the smaller sector of the cam by a threaded spindle (3) rotated by gearing (11,12) from a stationary positioning motor (10) driven in either direction at constant speed.

Description

The invention relates a jack drive according to the preamble of claims 1 and 3, respectively.

Lifter inking units are widely used in sheetfed offset presses. Such lifter inking units have one with an ink fountain in addition Dosing device interacting ink fountain roller on the Surface of the ink to be printed in the form of a zonal layer adjustable thickness is applied. One between the ink fountain roller and a downstream inking unit roller, usually one Grater roller, reciprocating siphon roller takes through the intermittent contact with the ink fountain roller of a certain length and passes this amount of color to the next one Contact to the inking roller or friction roller from this. A further multiple takes place through further, following inking unit rollers Splitting the amount of ink fed through the squeegee roller. About the at the inking rollers set in the forme cylinder then take place Applying the color to the printing form.

The coordination of the following the setting up of the printing press Color guidance in accordance with specified target specifications takes place in the Usually at a lower printing speed (e.g. 5,000 sheets / h) as the subsequent production. The production speeds the high-speed sheetfed offset press known today can be of the order of 15,000 sheets / h. With this typical in printing practice Procedure is always found that one is lower Coloring set at the machine speed then ramping up the printing speed accordingly changed that the color densities detectable on the printed sheet, for example, the measuring fields of a pressure control strip. The ones made when tuning at slow print speeds Print sheets therefore have a higher color density than those that are then at the actual production speed getting produced. The effect briefly described here will also referred to as paint waste. The reverse effect - Color increase - occurs with a corresponding reduction the printing speed.

From the prior art, numerous types of drive are one Lifting roller known. The drive of a lifting roller by means of a Cam gear is for example on the DD 276 455 A1 and the DD 212 475 B1 known. The curve in the drive of the former Scripture is driven by a speed-adjustable electric motor, where the speed of the electric motor control technology is coupled to the speed of the printing unit of the machine. Of the Lifter drive that can be temporarily stopped according to a locking lever the DD 212 475 B1 is used to set the lifting stroke to amount of ink to be supplied.

A purely electronically controlled lifter drive is, for example known from GB 2 193 926 A. But from this writing is not see the kinematics according to which the lifting roller between Ink fountain roller and downstream inking roller is moved.

A pressure medium-operated jack drive is also from the U.S. Patent 3,013,489 known. The lifting roller is pivoted here via pressure cylinders that can be pressurized, whereby the pressure medium is pressurized by a feed pump and by a machine-synchronized control spool the chambers of Working cylinder is fed. Even if you constant Delivery pressure of the pump is assumed, the jack roller in its Movement between the ink fountain roller and the downstream inking roller have kinematics which depend on the printing speed depends. This is because the spool in Clock of the printing speed is driven.

The lifter drives cited above are capable of the problem of formed color drop especially in high-speed sheetfed offset printing machines not to solve. A cause for the color drop must can be seen in particular in that the jack roller when starting to the ink fountain roller due to a difference in peripheral speeds a floating on the color layer of the Ink fountain roller experiences. Especially at high printing speeds but are the times when the lifter roller with the ink fountain roller is brought into contact, very briefly. Thus at high printing speeds the ink transfer from the ink fountain roller to the jack roller getting worse. A comparable one The process also plays out when the color of is transferred from the lifter roller to the downstream inking roller.

To the last described effect of the floating of the lifting roller on the ink fountain roller or the downstream inking roller to counteract this, drives have been known in the past become, at which the peripheral speed of the jack roller too which synchronizes the ink fountain roller or downstream inking roller become. Such drives are very constructive complex and solve the problem of ink decay at high printing speeds still not.

From GB-A-12 15 517 a lifter inking unit for a printing press is known in which the lifting roller by means of a double-acting working cylinder which can be pressurized with pressure medium is driven. The pressure medium is supplied to the working cylinder via controllable valves on the part of a hydraulic pump. The electric valves are Upstream timer for controlling the movement.

WO-A-90 13 427 discloses an ink transport mechanism of the type mentioned above Lifter inking unit is known, in which a lifter roller is also provided with a pressure medium acted upon, double-acting cylinder is controlled.

A lifter inking unit for a printing press is ultimately known from US Pat. No. 4,524,692. in which the lifting roller is pressure-medium controlled by an assigned working cylinder is movable between the ink fountain roller and a downstream inking roller. The pressure of the working cylinder is controlled electrically.

The object of the present invention is therefore a lifter drive according to the preamble of claim 1 or claim 3 to improve such that the transmission of Ink from the ink fountain roller to the inking unit largely depends on the printing speed becomes independent and is particularly noticeable at very high printing speeds perceptible color drop can be counteracted.

This object is achieved by the characterizing features of claim 1 or Claim 3. An advantageous embodiment of the invention results from the Claim 1 related claim 2.

According to the invention it is preferably provided that the on and Stop movement of the lifting roller with respect to the ink fountain roller a time function that is independent of the printing speed is.

According to the invention it can also be provided that not only the Movement of the lifting roller for turning on and off with respect to the ink fountain roller for a print speed independent Time function is carried out. It is preferably also possible that starting and stopping the jack roller with respect to the subordinate Inking roller after one of the printing speed of the machine independent time function. In this variant of Invention has the advantage that the lifting roller impacts on the following inking rollers independently from the printing speed.

The invention makes use of the knowledge that the in Offset printing technology used colors distinct non-Newtonian Have properties. Thus, the jack roller is always after the same time function to and from the ink fountain roller turned off again, so there can be no printing speed dependent Changes in color transfer are coming.

The invention preferably comes with an ink fountain roller and Lifter drive for use in which the ink fountain roller at all printing speeds in the same way in time is driven, in particular regardless of the printing speed revolves constantly at a speed. To at higher Print speeds per unit of time corresponding to more color in To promote the inking unit, the contact angle of the siphon roller is on the ink fountain roller increases with increasing printing speed.

According to a simple embodiment of the invention, the drive for the lifting roller to be such that a cam disk is used finds which of a speed controlled electric motor is driven. The speed control upstream of the motor is thereby such that the cam disc with one of the printing speed of the machine independent, predetermined constant Speed runs when the role of the Bearing lever of the lifting roller runs over those curve sections, which in particular the switching on and off of the lifting roller to the Effect ink fountain roller. After starting and stopping the lifting roller in particular, the ink fountain roller is in turn driven the cam with a speed, which with the printing speed the machine correlates. The times at which switching the speed of the control cam from a machine-synchronous can take place at a constant speed value for example by sensory scanning of the control curve respectively. A corresponding evaluation is also one of the Printing machine attached angle encoder possible.

Furthermore, a preferred embodiment is explained the invention with reference to the drawings. In this A cam disc is used, which embodiment is driven by the inking unit, i.e. rotates at a speed, which depends on the printing speed of the machine. By A controllable lifting device causes the lifting roller always after the same time function to the ink fountain roller is turned on and off by this.

Fig. 1

einen erfindungsgemäßen Heberantrieb mit Kurvenscheibe und Schwenkhebel,

Fig. 2+3

die Kurvenscheibe in zwei verschiedenen Winkelstellungen sowie

Fig. 4+5

die Stellung der Kurvenscheibe gemäß den Figuren 2 und 3 im Schnitt.

1 to 5 show:

Fig. 1

a lifter drive according to the invention with cam and swivel lever,

Fig. 2 + 3

the cam in two different angular positions as well

Fig. 4 + 5

the position of the cam according to Figures 2 and 3 in section.

Fig. 1 shows one over the format width of the printing press extending ink fountain 1 with which a rotatable ink fountain roller 2 interacts. Between the ink fountain roller 2 and a downstream inking roller 4 is a jack roller 3 back and forth movably stored. In the downstream inking roller 4 can it is in particular an axial traversing movement Act friction roller.

The lifting roller 3 is in one at its two ends Swivel lever 5 rotatably mounted. The two pivot levers 5 are with a shaft 6 extending with one another over the format width connected, which is pivotally mounted fixed to the frame. An end a pivot lever 5 has a rotatable on an extension stored roller 7, which is on the outer contour Dependent on the printing machine speed rotating Control curve 8 expires. By spring means, not shown the roller 7 pressed against the outer contour of the cam 8. Of the drive of the control cam 8 derived from the printing or inking unit be such that the control cam 8 rotates once, when the printing machine makes three single revolutions (lifting stroke 1: 3).

According to FIGS. 1 to 3, the control curve 8 has two radii, where the lifter roller 3 on the downstream inking roller 4 abuts when the roller 7 on the large radius of the cam 8th expires. Accordingly, the jack roller 3 lies on the ink fountain roller 2 when the roller 7 is on the smaller radius of the control cam 8 expires.

The swivel lever 5 having the roller 7 is a lifting device 9 assigned such that the roller 7 from the outer contour of the Control cam 8 can be lifted so that the lifting roller 3 neither on the Ink fountain roller 2 still on the downstream inking roller 4 is present. Through the lifting device 9 according to the invention Roll 7 in an area between the small and large radius of the Move cam 8.

The lifting device 9 according to the invention is in one embodiment the invention from one in two directions of rotation each at a constant speed rotating servomotor 10, which is fixed to the frame is hung. On the rotor shaft of the servomotor 10 is a Pinion 11 attached, which is designed as a spur gear is. This meshes with a second pinion 12, which the end of a screwed in a thread 14 fixed to the frame Threaded spindle is attached. The pinion 12 has one Width so that the threaded spindle in the intended stroke range 13 the pinion 11 always with its entire width Pinion 12 remains in mesh.

In Figures 2 and 3 it is shown how by the invention Lifting device 9, in particular through the one stroke exerting threaded spindle 13, the roller 7 of a pivot lever 5 can be lifted off the small radius of the control cam 8 or on again this is adjustable. The depending on the printing speed revolving control curve 8 comes based on the situation 1, after about half a turn with the transition from large to the small radius in the area of roll 7. First The roller 7 then runs on the sloping outer contour of the control curve 8, so that the lifter roller 3 is parked by the inking roller 4 becomes. Since the threaded spindle 13 to the maximum provided Stroke is extended, the role 7 does not come on now small radius of the rotating control cam 8 to lie, but the pivot lever 5 is locked in such a way that the lifting roller 3rd an intermediate position between ink fountain roller 2 and inking roller 4 occupies.

As shown in Figures 4 and 5, at the end of Swivel lever 5 parallel to each other two rollers 7, 15 rotatable arranged, roller 7 runs on the cam 8 and roller 15 is assigned to the end of the threaded spindle 13.

After the roller 7 of the large radius of the cam 8 has expired and the swivel lever 5 by fitting the roller 15 is locked on the extended end of the threaded spindle 13, the actuator 10 is now controlled so that the threaded spindle 13 a piece is screwed into the thread 14 fixed to the frame. This has the consequence that roller 7 on the small radius of the cam 8th comes into circulation and runs there. The jack roller 3 is now on the Ink fountain roller 2 started.

Since the invention provides for the actuator 10 to the scheduled time at a constant speed - independent of the printing press speed - is thus the Adjustment movement of the lifter roller 3 to the ink fountain roller 2 always carried out according to the same time function. The threaded spindle 13 in connection with the frame-fixed thread 14 and the corresponding trained actuator 10 thus provides a lifting device 9 represents, the work movement always after the same time function is performed.

After that on the outer contour with the small radius of the control curve 8 offset roller 7 almost the entire contour area with the small radius of the control curve 8 has now expired Actuator 10 in the reverse direction to extend the threaded spindle 13 driven from the thread 14 fixed to the frame. This causes the roller 7 before reaching the contour transition to large radius of the cam 8 lifted from the small radius becomes. Here, too, the constant drive speed of the actuator drives 10 in conjunction with the threaded spindle 13 that the Lifter roller 3 according to a machine speed independent Time function turned off by the ink fountain roller 2 and for a short moment takes a position in which she does not rest on the ink fountain roller 2 nor on the inking roller 4. Now that the threaded spindle 13, the swivel lever 5 over the roller 15 has pivoted into an intermediate position, runs with another Rotation of the cam 8, the roller 7 on the rising contour the control cam 8, so that now the lifting roller 3 to the inking roller 4 is employed. Starting and stopping the jack roller 3 to the inking roller 4 thus takes place in the cycle of the rotating Control curve 8, during the turning on and off of the lifting roller 3 the ink fountain roller 2 by the lifting device described above 9 is effected.

Figures 4 and 5 show again the positions of the rollers 7, 15 according to Figures 2 and 3 in section. FIG. 4 shows that by the threaded spindle 13 of the lifting device 9, which on the roller 15 acts, the roller 7 of the small radius of the Control curve 8 is lifted. The control is now carried out of the actuator 10 of the lifting device 9, so that on the role 15 the roller 7 in contact with the small radius of the cam 8 brought. As explained above, the lifter roller is now in place 3 on the ink fountain roller 2.

Now that the roller 7 is almost in the entire area of the small radius the control curve 8 has expired, control is now carried out again in the lifting device 9 so that the threaded spindle 13 over the Roll 15 the roll 7 from the small radius of the cam 8 takes off and spends in the intermediate position described. The Lifter roller 3 is now switched off from the ink fountain roller 2 and will hired to the inking roller 4 as soon as by further turning the Control curve 8 the role 7 from this intermediate position on the Contour of the large radius runs up.

The actuator 10 on the lifting device 9 described above is connected to a controller, not shown, which impulses for activation at the times indicated above the actuator 10 causes. As already mentioned above The control can be operatively connected to sensors stand, which markings on the control curve 8 scan or the Transition of the control curve 8 from the large to the small radius and vice versa. It can also be possible by means of the control be the triggering times for the lifting device 9 in dependence the printing speed. For example serve to perform dead time compensation or to Lift system angle on the ink fountain roller 2 at the printing speed to enlarge.

Reference list

1

Paint box

2nd

Ink fountain roller

3rd

Lifter roller

4th

Inking roller

5

Swivel lever

6

wave

7

role

8th

Control curve

9

Lifting device

10th

Actuator

11

pinion

12th

pinion

13

Threaded spindle

14

thread

15

role

Claims (3)

1. Ductor drive for the ductor roller in ductor inking units of a printing press, particularly an offset sheet printing press, in which a ductor roller (3) is mounted movably between an ink fountain roller (2) and a subsequently arranged inking unit roller (4) and by means of a ductor drive (8 - 14) is periodically alternately set against the ink fountain roller (2) and against the subsequently arranged inking unit roller (4), wherein the ductor drive (8 - 14) has a control cam (8) with a roller (7) running off on at least two different radii of the control cam (8), characterised in that the ductor drive (8 - 14) is constructed for the purpose of setting on and off the ductor roller (3) on at least one of the rollers (2, 4) carrying out a movement which takes place in accordance with a time function which is independent of the print speed, for which the control cam (8) is driven from the printing unit and that the control cam (8) has fitted to it a controllable lifting device (10 - 14) by means of which the roller (7) can be lifted from a smaller radius of the control cam (3) and can be brought into a position between two radii of the control cam (8).
2. Ductor drive according to Claim 1, characterised in that the lifting device (10 - 14) has a threaded spindle (13) threaded into a thread (14) fixed with respect to the frame and the threaded spindle (13) can be driven by a controllable adjustment drive (10).
3. Ductor drive for the ductor roller in the ductor inking unit of a printing press, particularly an offset sheet printing press, in which a ductor roller (3) is mounted movably between an ink fountain roller (2) and a subsequently arranged inking unit roller (4) and is set by a ductor drive (8 - 14) periodically alternating against the ink fountain roller (2) and against the subsequently arranged inking unit roller (4), wherein the ductor drive (8 - 14) has a control cam (8) with a roller (7) running off on at least two different radii of the control cam (8), characterised in that the ductor drive (8 - 14) is constructed in order to impart a movement to the ductor roller (3) setting on and off against at least one of the rollers (2, 4) which takes place in accordance with a time function which is independent of the print speed, for which the control cam (8) has a drive controllable in terms of its rotational speed via which the control cam (8) periodically is drivable both with a rotational speed dependent upon the printing press speed as well as with a fixed preset rotational speed independent of the printing press speed.

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