JPH0455594B2 - - Google Patents

Abstract

In order to provide minute dosing of a liquid-film on a rotating roller (5) of a printing press so as to achieve the necessary thickness for subsequent processing, a wiping band (14) is so positioned that it wraps round the roller (5) to an adjustable angle ( alpha ). By this means, the liquid-film (13) produced by a liquid-dispensing unit (7) is partially removed. The rotating roller (5) transfers the minutely dosed liquid-film (24) directly onto the form cylinder (4) of a printing press.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Application The present invention relates to an apparatus for precisely metering a liquid film onto a rotating printing press roller. More specifically,
The present invention is a device for precisely metering and uniformly distributing a liquid film onto a rotating roller of a printing press, which is designed to be wrapped around the rotating roller, wipe away excess ink, and return it to a container. The liquid is delivered through an applicator using a liquid-permeable belt,
The applicator relates to a liquid film metering and dispensing device in which the liquid film is completely renewed on each rotation of the rotating cylinder.

[Prior art]

This type of device is shown in DE-OS2146065,
In this device, a gauze is stretched so as to be pressed against the ink dispenser roller in order to dispense a predetermined amount of ink onto the ink dispenser roller of a roller-type ink soaking device of an office offset printing machine. The ink ductor roller has a considerably lower circumferential speed than the plate cylinder on which the plate is mounted. For this reason,
It is necessary to place an ink transfer roller after the ink ductor roller. This ink transfer roller receives ink at the same circumferential speed as the ink ductor rotates and transfers this ink to a first inking roller that has the same circumferential speed as the plate cylinder. The ink is received by the ink fountain roller and the first
This back and forth movement of the ink transfer roller during transfer to the first inking roller, of course, does not result in a uniform ink film on the first inking roller. The formation of a uniform film is essential for inking plates. For this reason, it is essential to arrange a number of additional inking rollers between the first inking roller and the form cylinder. These additional rollers ensure that the irregularly supplied ink is evenly distributed so that a uniform film is transferred to the plate.

Devices are also known in which liquid is metered onto rollers so that a satisfactory liquid film is formed without the need for a series of distribution rollers. DS-OS2812998 shows a roller that applies ink directly to the printing plate on the plate cylinder.
This roller essentially has a soft elastic surface. The ink transferred from the ink channel to the roller is wiped off by an inking knife to obtain the required thickness for subsequent processing. However, since the thickness of the ink film is approximately several thousandths of a millimeter, a very strong force is required to press the ink film to overcome the hydrodynamic pressure. Therefore, the surface of the roller undergoes significant elastic deformation. This inevitably leads to heavy heating and high wear, and these are of high degree depending on the speed.

In DE-OS3217569, DE-OS2812998
An ink applicator roller with an elastic surface conforming to the ink applicator drum is mounted in front of the ink applicator drum with a rigid surface, and the ink film is deposited on this ink applicator drum via a metering element in order to avoid significant elastic deformations of the soft surface of the roller. It is formed.

This additional cost of the ink applicator roller is
In order to prevent the occurrence of so-called ghosts, it must have exactly the same diameter as the plate cylinder. However, an additional inking roller must be arranged between the plate cylinder and the inking drum in order to prevent direct contact between the two hard-surfaced rollers.

The ink film formed on the ink applicator roller is not completely equalized and is not updated. The remaining ink film not picked up by the plate cylinder and remaining on the ink applicator roller is covered with fresh ink during the next contact step that takes place during each new rotation. This can produce smudged, muddy prints. This contamination can cause metering caps to clog, which can lead to uneven ink delivery and increased wear.
These contaminant particles can cause significant wear on the support body/inking drum contact line. At the same time, the risk of ink buildup due to residual films remaining on the inking drum is very high. This accumulation must be disposed of in some way.

The accuracy requirements of the metering element and the inking drum are very high, which also increases the cost of the inking device.

[Purpose of the invention]

The basic object of the invention is to provide a device for producing a precisely metered liquid film on a rotating cylinder with the smallest possible number of rollers.
With each rotation of the rotating cylinder, this membrane is completely updated and equalized, avoiding the disadvantages mentioned above.

[Summary of the invention]

According to the invention, a rotating roller is brought into contact with a plate cylinder whose axes are parallel, and by means of at least one wiping belt wound around the rotating roller, the amount required for the subsequent processing of the printing plate is removed. The problem is solved by an apparatus in which a liquid film is transferred and the rotating roller has a circumferential speed that actually corresponds to the circumferential speed of the plate cylinder.

In devices of this type, the surface finish and surface hardness of the rotating rollers can be adapted accordingly to the printing process, the liquid to be processed or the processing speed. In order to accurately meter the liquid film onto the rotating roller, metering screws and extensive control systems for them are no longer required. The properties of the belt can be varied almost at will and adapted to process requirements. This is because, at printing speeds, due to the hydrodynamic pressure that develops in the wiper belt and rotating roller rotation, complete lubrication is provided and wear is extremely low.

[Explanation of Examples]

Embodiments of the present invention will be described below with reference to the drawings.

[Explanation of Examples]

FIG. 1 is a schematic illustration of a printing unit of a printing press in which a paper web 1 is being printed in a conventional manner and is fed between a blanket cylinder 2 and an opposing impression cylinder 3. Thus, both the blanket cylinder and the impression cylinder are rotatably mounted on a machine frame (not shown). The blanket cylinder 2 is paired with a plate cylinder 4, and the printed content is transferred from the plate cylinder to the blanket cylinder. The plate cylinder 4 is
Receives ink and/or dampening material from rotating roller 5. Like the blanket cylinder 2 and the plate cylinder 4, the rotating rollers are driven at the same circumferential speed by conventional means (not shown).

Rotating roller 5 receives liquid 6 from liquid applicator 7. This liquid applicator is usually
It is composed of a rear wall 8, a side wall 9, a measuring knife 10, and a rotating roller 5. The width of the cap 11 between the rotating rollers 5 of the metering knife 10 is set by the adjusting screw 12 before operation and determines the film thickness 13 of the liquid drawn off by the rotating rollers 5. Wiping tape 14, which can typically be made from plastic and/or metal fabric, has its ends wrapped around a spool.

One end of the wipe tape is wound onto a fixed, rotatable and controllable unwinding shaft 15, and the other end is wound onto a drivable take-up shaft 16. The winding shaft 16 is
In order to adjust the encircling angle α, the circular arc path 17 (arrow 1
8) in a conventional manner.

The tension of the wiping belt 14 can be varied by means of a brakeable feed-out shaft 15.

A brakeable unwinding shaft 15 and a drivable winding shaft 16 are arranged such that by winding the shaft in the direction indicated by arrows 19 and 20,
A simple embodiment makes it possible to replace worn areas of the wiping belt 14 with new areas.
This can be done even when the printing press is in operation.

The wiping band 14 wipes the liquid on the rotating roller 5, and the liquid falls into the container 22 through the intermediate space. From there, the liquid 23 is routed via a pipe system (not shown) to a conventional reconditioning device. The remaining liquid film 24 is then sent to the plate cylinder 4. The remainder 25 that still remains is completely renewed in the liquid reservoir.

Depending on the printing mode, the blanket cylinder 2 can be replaced by an impression cylinder, the plate cylinder can be replaced by a plate cylinder suitable for the printing mode, and the printing web can be passed between the two rollers.

FIG. 2 shows one possible form of a device for precisely metering a liquid film onto a rotating roller 5. FIG. In this case, the wiping band 14 is configured as an endless belt 24. This endless belt 24
is passed over three pulleys. Drive pulley 25
is rigidly fixed to a rotatable fixed shaft 26 driven by a continuously variable motor 27. The swivel pulley 28 is mounted on the shaft 29, but its position can be changed to adjust the wrap angle α. A tension roller 30 is rotatably mounted on a shaft 31. The shaft 31 has a lever 3 which can be rotated about a permanently arranged pivot pin 33.
It is rigidly attached to one end of 2. Lever 3
The other end of 2 is connected by a link to a pressure cylinder 34 which is rotatably held by a fixing pin 35. The tension in the endless belt 24 is obtained by adjusting the pressure of the medium acting therein using a pressure cylinder 24. The rotating roller 5 is
A cavity 36 is provided to make it possible to cool the roller if necessary.

By using the endless belt 24, a constant relative speed can always be obtained between the endless belt 24 driven by the motor 27 and the rotating roller 5. This constant relative speed is independent of machine speed and
It is thus possible to obtain a completely uniform film on the rotating roller 5 at any printing speed.

The device shown in FIG. 3 also includes an endless belt 24 of the same configuration as shown in FIG. The endless belt 24 includes a drivable pulley 37 and a rotating pulley 3.
A drive pulley 37 running on 8 and a tension pulley 39 is driven by a continuously variable motor 27. Another pulley 41 mounted on a permanently fixed shaft 42 is located near a cleaning material container 43 filled with cleaning material 44 . When not in use, the cleaning material container 43 is in the low position 45.
It can descend to (the chain line position). The belt is passed through a device 46 or 47 which removes excess cleaning material from the endless belt 24, for example by a wiping action. Device 46 or 47 depending on the direction of endless belt 24
mesh together. This arrangement also allows cleaning of the rotating roller 5.

FIG. 4 shows another type of wiping belt. The base material may be formed from a film 48, which can typically be made of metal or plastic. The side of the belt facing the rotating roller 5 has a smooth surface, and the belt itself has a large number of rows of holes 49.
Pre-drilled by. By way of example, oval holes 50 allow liquid wiped away by material 51 between the rows of holes to drain and flow into container 22 .

FIG. 5 shows an alternative design for the wiping belt used in the device described above. A bar 55 is disposed on the non-stretchable flexible belt strips 52, 53, 54. The space 56 thus created allows the liquid wiped by the bar 55 to drain and flow into the container 22 (FIG. 1).

For the belt design shown, optimal matching to the working conditions of the printing process is determined by the appropriate selection of the fabric of the belt in woven form, the tape and the dimensions of the holes 50 (fourth
It can be obtained by selecting the bar width and spacing a as shown in FIG. Due to the adjustability of the belt tension and the wrap angle α, almost any thickness of liquid film can be formed on the rotating roller 5.

Of course, all adjustment means of the invention can be automated by storing various adjustment parameters in the controller and running various programs.

The entire wiping belt holding means and/or liquid container can be accommodated in a plurality of box units that have lateral divisions and can therefore be easily scaled up and down. The width of the total enclosure can be selected such that a number of box units can be placed across the width of the roller.

[Brief explanation of the drawing]

FIG. 1 is a simplified side view of a printing device with a wiping belt type device wrapped around a roller to form a finely metered liquid film; FIG. 2 is a side view of the roller and endless belt. , FIG. 3 is a surface view of the rollers and the endless belt running through the cleaning device, FIG. 4 is a perspective view of one possible form of the wiping belt, and FIG. 5 is a perspective view of another possible form of the wiping belt. It is a diagram. 1: paper web, 2: rubber cylinder, 3: impression cylinder,
4: Plate cylinder, 5: Rotating roller, 6: Liquid, 7: Liquid applicator, 10: Measuring knife, 12: Adjusting screw, 13, 24: Liquid film, 14: Wiping tape, 1
5: Feeding shaft, 16: Winding shaft, 2
2: Container, 23: Liquid.

Claims (1)

[Claims] 1. A device for accurately measuring and uniformly distributing a liquid film on a rotating roller of a printing machine, wherein the liquid is wound around the rotating roller 5 and wipes away excess ink. from an applicator using a liquid-permeable distribution belt designed to return the liquid to the container, the applicator completely renewing the liquid film with each revolution of the rotating roller, said rotating cylinder 5 At least one belt 14, which is parallel and in contact with the printing form cylinder 4 carrying the printing form, and wound around the rotating cylinder 5, carries a liquid film in such an amount as is required for the subsequent processing of the printing form. 24
device for metering and uniform distribution of a liquid film onto a rotating roller, characterized in that the rotating cylinder 5 has a circumferential speed that approximately corresponds to the circumferential speed of the plate cylinder 4. 2. The wiping belt 14 is unwound from the brake shaft 15 and wound onto a winding shaft 16, which winding shaft can be moved along an arcuate path to adjust the winding angle (α). A device for measuring and uniformly distributing a liquid film onto a rotating roller according to item 1. 3. The wiping belt 14 is formed as an endless belt 15 and is wrapped around at least one drive pulley 25, swiveling pulley 28 and tension pulley 30. Metering and uniform dispensing equipment. 4. The apparatus for measuring and uniformly distributing a liquid film onto a rotating roller according to claim 3, wherein the rotation direction of the pulley that drives the endless belt 24 can be freely selected. 5 Pulley 25 and endless belt 2 together with it
5. The device for measuring and uniformly distributing a liquid film onto a rotating roller according to claim 4, wherein the speed of the drive means 27 for driving the roller is continuously variable regardless of the drive means of the machine. 6. Device for metering and uniform distribution of liquid films onto rotating rollers according to claim 5, in which the endless belt 24 is guided via cleaning devices 43, 44. 7. Device for metering and uniform distribution of liquid films onto rotating rollers according to claim 6, in which the cleaning devices 43, 44 can be moved from the area occupied by the endless belt 24. 8. Apparatus for metering and uniformly distributing a liquid film onto rotating rollers according to claim 6 or 7, wherein means 46, 47 are provided for removing the cleaning liquid carried by the endless belt 24. . 9. Apparatus for metering and uniformly distributing a liquid film onto rotating rollers according to any one of claims 1 to 8, wherein the wiping belt 14 or 24 is made of plastic and/or metal fabric. 10. Claims 1 to 24, wherein the wiping belt 14 or 24 is made of a membrane with a smooth surface, and perforations 50 of arbitrary shapes are distributed over the entire wiping range.
Apparatus for metering and uniformly distributing a liquid film onto a rotating roller according to any of clause 8. 11 The wiping belt 14 or 24 consists of a plurality of belt strips 52, 53, 54, which strips are interconnected by spaced bars 55 arranged on the side of said wiping belt which wipes liquid away from the surface of the roller 5. A device for metering and uniformly distributing a liquid film onto a rotating roller according to any one of claims 1 to 8, which is connected to a rotary roller.