DE4205682A1 - DEVICE AND METHOD FOR PRINTING MATERIALS - Google Patents

Description

The invention relates to a method for printing on Material webs, one on a heated cliché cylinder arranged cliché one on top of this applied thermoplastic paint on the be printing material web transfers and the cliché at Circulation of the plate cylinder on one with the thermo plastic paint soaked foam roller rolls off. The corresponding device consists of a counter printing cylinder with an elastic support for guidance the material web and a cliché cylinder, the one with foam roller soaked in thermoplastic paint assigned.

For printing on material webs are preferred Flexographic printing used with flexible printing shapes and liquid, solvent-based paints The corresponding device consists in the main thing from an impression cylinder for guiding the mate rialbahn, a cliché cylinder and an associated Inking roller. The feeding of the paint to the paint application roller is usually done by immersion roller that dips into an ink pan. The color will  thereby about the combination of dip roller and ink applicator roller on the cliché cylinder che cliché.

Signing devices are also known in which the required color from a bottle is closed with a permeable membrane is.

In these known printing devices there is Ge drive in the color when there is a business interruption dries, or that the viscosity of the paint during of the company can change. The consequences are incorrect or unusable printed images. In addition, at no pigmented colors when using membranes are used, for example for printing with white color on dark background. Should z. B. Material webs are printed in the form of plastic films, so it is often necessary to use a corona pre-treat discharge.

Other disadvantages of these known printing devices be are that especially when double-sided printing long drying distances are required.

To avoid these disadvantages, printing devices have been developed gen developed in which a heated metal cliché a previously applied thermoplastic Transfers color to the material web to be printed. At a drink with this color is used for these devices tes foam rubber roller as a color memory, whereby the the aforementioned disadvantages are largely avoided can.

With these printing devices, however, the disadvantage is too  record that of the in the foam roller brought back only a much smaller proportion of color can be removed. There is also a reuse dung, d. H. a soaking of the used foam rubber roll uneconomical and therefore not useful. By the relatively low productivity of thermo of plastic paint soaked in foam rubber rolls Printing process for changing the foam rubber rolls often un be broken.

The invention is therefore based on the object Method and device for printing on mate rialbahnen to create an uninterrupted Printing process is made possible and optimal utilization the available thermoplastic color is enough.

In the process of printing on material web over carries a arranged on a heated cliché cylinder cliché a thermo previously applied to this plastic ink on the material web to be printed. The Cliché rolls up as the cliché cylinder rotates a foam soaked with the thermoplastic paint rubber roll off.

According to the foam roller during the Printing process thermoplastic ink supplied from the outside.

In an expedient development of the invention the supply of thermoplastic paint intermittently rend so that the amount of paint applied can be controlled can.

Preferably the thermoplastic paint becomes the foam rubber roll fed in the form of a solid fabric.  

It has proven to be particularly useful that feed thermoplastic paint in the form of a color bar On the other hand, there is also a color as a solid material powder in question.

The device for printing webs of material exists from an impression cylinder with an elastic on location for guiding the material web and a cliché cylinder, one with a thermoplastic color Soaked foam roller is assigned, the Kli schee cylinder and the foam rubber roller in one heater are arranged.

The device according to the invention is characterized by a feed unit via which the be in the heating chamber sensitive foam rubber roll of thermoplastic paint is fed outside.

Due to the temperature prevailing in the heating chamber the thermoplastic paint is in the liquid state of the Foam roll fed. This can be an endless Printing process can be realized without an exchange the foam roller would be required.

In a preferred development of the invention Device in which the thermoplastic paint in the form a color bar is fed, there is the feeder unit from a feed chute that opens through an opening the heating chamber in connection with the foam rubber roller stands.

It is also expedient to open the feed chute at the top execute so that the used during printing Color bars in a simple way with a new color bar  ren can be replaced.

To facilitate the feeding of the color bar inside of the feed chute through the opening, it is advantageous if the opening knocks towards the feeder shaft nisch expanded.

In a further development of the invention is the feed shaft with a conveyor to promote the color bar towards the foam roller. This can the intensity and timing of the ink application be controlled.

It is also useful in the lower area of the Zu guide shaft to arrange an empty indicator, for example may consist of an optical sensor. This Empty detector is used to display the consumption status of the Color bars, so that in time before the final Ver need the color bar a new color bar in the Zu guide shaft can be used.

The particular advantages of the invention can be seen therein hen that on the one hand an exchange of used foam rubber mirollen is no longer required and on the other hand one continuous printing with constant quality can be realized. This will turn them on falling costs to a minimum. It can also Device is constantly ready for printing, without subsequently having an otherwise possible quality reduction can occur when the pressure is continued. Of further the color used is used to the maximum. Another advantage of the invention is that it it is possible to feed the color bars intermittently, so that control of the melting process and thus the color application can be done on the foam rubber roller.  

The invention is based on an embodiment example explained in more detail.

The device for printing webs of material 2 with a thermoplastic ink consists, according to the drawing figure, of a rubberized impression cylinder 1 for supporting and guiding the web of material 2 to be printed, which can also consist of a plastic film. Parallel to this impression cylinder 1 a Kli schee cylinder 4 is mounted, on the outer surface of a plate 3 is attached. The distance of the counter-pressure cylinder 1 to the plate cylinder 4 is set so that the plate 3 rolls on the web of material 2 passed between the two cylinders and the color on the plate 3 can carry over the material web 2 . Subsequent to the plate cylinder 4 , a foam rubber roller 6 is mounted at intervals. From stood the foam rubber roller 6 to the plate cylinder 4 is slightly less than the thickness of the plate 3 , so that this rolls once on the foam roller 6 with each revolution of the plate cylinder 4 . The color located in the foam rubber roller 6 is transferred to this according to the surface structure of the cliché 3 .

Since the printing of the material web 2 is to take place with a thermoplastic color, the cliché cylinder 4 and the foam rubber roller 6 are accommodated in a heating chamber 5 .

Above the foam rubber roller 6 , an opening 7 is provided in the heating chamber 5 , through which an ink bar 8 can be inserted into the heating chamber 5 . For this purpose, a vertically arranged feed shaft 9 is fastened above the opening 7 , the cross section of which corresponds to the dimensions of the color bar 8 to be fed. The opening 7 widens conically in the direction of the feed channel 9 , whereby the insertion of the color bar 8 is facilitated. Disturbances by possibly jamming or tilting color bars 8 in the opening 7 are also avoided.

The opening 7 in the heating chamber 5 and the associated guide shaft 9 can also be arranged in another place of the Heizkam mer 5 . An oblique or horizontal arrangement would also be conceivable. The function described below is not affected.

If a color bar 8 is now inserted into the feed shaft 9 and placed on the foam rubber roller 6 , the paint melts, which is distributed by the rotation of the foam rubber 6 on it.

In order to achieve an optimal color distribution, a conveyor 10 is arranged within half of the feed shaft 9 , with the aid of which the conveyance of the ink bar 8 can be controlled in the direction of the foam rubber roller 6 . The color bar 8 is preferably fed intermittently. The ink supply is controlled by a preselection counter, not shown, depending on the number of prints. This allows the amount of color supplied to be regulated and interrupted if necessary. That is e.g. B. the case when the material web 2 must be exchanged for another material web 2 . Since in this case the printing device has to be stopped, but the heating in the heating chamber 5 continues to operate, further color would melt from the ink bar 8 if it remains on the foam rubber roller 6 . If the feed is stopped at this time, no color can melt.

When the printing device is restarted, only the intermittent feeding of the color bar 8 then has to be continued.

To avoid an otherwise possible interruption of the ink supply, an empty indicator 11 is arranged in the lower region of the feed chute 9 , which indicates when a new ink bar 8 is to be inserted. This empty detector 11 can consist, for example, of an optoelectronic sensor.

The device described above ensures the continuous printing of material webs 2 . Due to the constant and controllable ink supply through the feed shaft 9 , it is no longer necessary to replace the foam rubber 6 or it is possible to use it considerably longer. Replacing the foam rubber roller 6 is only necessary with their mechanical wear or with a change of color. Moreover, technologically act conditional Be not business interruptions more detrimental to the Qua formality from the printing result, as occurs simultaneously with the resumption of the printing operation, the supply of color by the color bars. 8

Reference list

1 impression cylinder
2 material web
3 cliché
4 cliché cylinders
5 heating chamber
6 foam rubber rolls
7 opening
8 color bars
9 feed chute
10 conveyor
11 empty alarms

Claims (11)

1. A method for printing on material webs, in which a cliché arranged on a heated cliché cylinder transfers a thermoplastic ink previously applied to it onto the material web to be printed and when the cliché rolls around the cliché cylinder on a foam rubber roller soaked with the thermoplastic ink, since characterized in that the thermoplastic ink is supplied to the foam rubber roller from the outside during the printing process. 2. The method according to claim 1, characterized ge indicates that the feeding of the thermoplastic color is intermittent. 3. The method according to claim 1 or 2, characterized characterized in that the thermoplastic color of the foam rubber roll in the form of a solid Substance is fed. 4. The method according to claim 3, characterized ge indicates that the thermoplastic Color of the foam rubber roll in the form of a color bar  is fed. 5. An apparatus for performing the method according to any one of claims 1 to 4, consisting of a Ge counter-pressure cylinder with an elastic pad for guiding the material web and a cliché cylinder, which is associated with a soaked with a thermoplastic paint foam rubber roller, the cliché cylinder and the foam rubber roller is associated with, are where arranged in the plate cylinder and the foam rubber roller in a heating body, characterized in that the foam rubber roller (6) located in the heating chamber (4) is fed via a feed unit thermoplastic color from the outside. 6. The device according to claim 5, wherein the thermoplastic ink is supplied in the form of a paint bar, characterized in that the feed unit consists of a feed shaft ( 9 ) which has an opening ( 7 ) in the heating chamber ( 5 ) with the foam rubber roller ( 6 ) communicates. 7. The device according to claim 6, characterized in that the feed shaft ( 9 ) is open at the top. 8. The device according to claim 6, characterized in that the opening ( 7 ) widens conically in the direction of the feed shaft. 9. Device according to one of claims 6 to 8, characterized in that the feed shaft ( 9 ) is provided with a conveyor ( 10 ) for conveying the color bar ( 8 ) in the direction of the foam rubber roller ( 6 ). 10. Device according to one of claims 6 to 9, characterized in that an empty detector ( 11 ) is arranged in the un lower region of the feed shaft ( 9 ). 11. The device according to claim 10, characterized in that the empty detector ( 11 ) is an optoelectronic sensor.