JP3035332B2 - Printing method for pattern support of display device and printing roller for the method - Google Patents

Abstract

In a printing roll (10) for transferring hot adhesive printing material from a printing pad to the front panel of a display support, the roll coating (13) consists of cast silicone caoutchouc which is free from silicone fluid. Due to the fact that silicone caoutchouc is used which is free from silicone fluid, it is guaranteed that, even in the case of subsequent prints, the subsequent printing materials adhere well to the front panel since their adhesive property is not reduced by silicone fluid which would have been transferred from the roll onto the panel. Although there is no silicone fluid as a separating medium in the roll coating, the printing material can still readily be detached from the coating since the latter has a very smooth surface due to the cast. <IMAGE>

Description

Description: FIELD OF THE INVENTION The present invention relates to a printing method, in particular for printing a strip of phosphor and black matrix on a flat or cylindrical printing pattern support, in particular a front panel of a display device. It is about the method. When the phosphor or black matrix particles have to be printed on the pattern support, they are mixed with a binder to produce adhesive properties by heating (hereinafter this mixture is called "hot glue"). This mixture is distributed on a printing block and transferred by a printing roller onto a pattern support. The invention also relates to a printing roller in such a method.

2. Description of the Related Art A method for transferring a hot-glue printing material from a printing block to a front panel of a display device is disclosed in, for example, German Patent Publication DE.
-OS37 09 206 A1. A flat printing block with a cavity pattern corresponding to the pattern of the structure to be printed is used. This cavity is filled with a mixture of printing ink, for example a thermosetting binder (adhesive) and the particular particles to be printed. The transfer from a flat printing block to a flat front panel is performed using tampon printing with a printing roller with a cylindrical tampon, ie with a relatively soft cover part made of silicone rubber. In such tampon printing, a silicone rubber tampon typically has a hardness of about 40.
~ 80 Shore A hardness. The printed pattern on the block is related to the pattern actually desired on the front panel such that the distortion caused by the temperature difference between the block being transferred and the front panel and also the distortion caused by the distortion of the print rollers is compensated The distorted and desired pattern is effectively reproduced on the front panel.

When printing a front panel for a color display, strips or dot structures are sequentially printed with three different phosphors, each of which emits a different color when excited by an electron beam. . In addition to this, often a black matrix strip or area is printed, which usually separates two adjacent phosphor strips with a black matrix strip. When such a pattern is generated, for example, the front panel is moved over a belt through four printing blocks, all of which are arranged at substantially the same height as the panel. The pattern is transferred when the panel is stopped in each block, using the back and forth printing rollers provided one for each printing block.

Printing patterns formed of printing ink or black matrix or other materials (eg, adhesive patterns, photoresist patterns) are generated not only on the front panel of the display device by electron beam excitation, but also on the liquid crystal display device. The electroluminescent display is formed on the front and rear substrates. The printed pattern support may be flat or curved, and may be a plate or foil.

[Problems to be Solved by the Invention] The transferred printing ink does not adhere well to the pattern support as the number of previous prints increases. Therefore, in the first print, the ink adheres better than in the last print. Therefore, it is a problem to find a printing method and an apparatus therefor that can transfer all the printing ink to the printing pattern support of the display device with high reliability.

[Means for Solving the Invention] A transfer device using a printing roller according to the present invention includes a printing block having a hot-glue printing material heated and liquefied, and attaching the hot-glue printing material of the printing block to a surface. And a print roller for transferring the same to a pattern support of a display device.The print roller includes a cover portion made of silicone rubber containing no silicone fluid, and further adjusts the surface of the print roller to a controlled temperature. And a heating device for heating the printing roller so as to maintain the printing roller at a set temperature several tens of degrees lower than the printing block.

[Operation] Basically, a tampon composed of silicone rubber containing a silicone fluid has been used in the tampon printing process. The silicone fluid acts as a separation or release agent, allowing the ink collected by the tampon to be easily transferred to the media to be printed. Despite the separating agent, the tampon receives a sufficiently large amount of ink when utilized by the printing block. It has been discovered that during printing of the support, a small amount of silicone fluid migrates to unprinted areas. Printing inks are very poorly adhered to areas wetted by such adhered silicone fluid.

The cover of the printing roller according to the invention is made of silicone rubber which does not contain silicone fluid, so that the above-mentioned effects do not occur during printing. Thus, a support surface with the same adhesion properties is obtained in all successive printings.

[Effects of the Invention] The removal of the silicone fluid from the silicone rubber cover portion of the roller not only leads to indirectly improving the adhesion of the ink supplied to the support in continuous printing, but also the roller cover. It was noted that the ink adhesion on the part was directly improved. Given the improperly selected thermosetting binder (adhesive) and improperly selected processing conditions, this effect can be achieved in situations where the printing ink is improperly transferred from the rollers to the support in a known manner. become. In this case, however, the adhesion of the support is poor, but the adhesion to the support is not so bad because of the improved adhesion to the rollers. It is therefore possible to use adhesives which exhibit particularly good adhesion to the support material. It is also useful to keep the printing block at a temperature significantly higher than the rollers and to keep the rollers at a higher temperature than the front panel. The former temperature difference is preferably about several tens of degrees, while the latter may be maintained at several degrees.

However, a very special effect is obtained when silicone-free silicone rubber cover printing rollers are cast. Such a printing roller has a very smooth surface that collects sufficient printing ink from the block and can be easily transferred to a print pattern support.

Silicone rubber can be produced in different broad hardness ranges even without silicone fluid. It was recognized that accurate printing of the structure could be performed if the roller cover was made softer as the structure to be printed became finer. When printing very fine printing matrix strips, the best results have been obtained with a rubber hardness of about 40 to 50 Shore A. To provide a rough structure, the hardness of the roller cover can be increased to about 80 Shore A.

The accuracy of the construction is also increased when the printing roller rotates very easily, ie when it is supported on a bearing that can rotate even when it is not driven. Best results were obtained with a non-driven printing roller made from silicone fluid-free silicone rubber and having a casting cover of about 40 to 45 Shore A hardness.

Examples The present invention will be described below with reference to the accompanying drawings.

The printing roller 10 shown in FIG. 1 is composed of a hollow metal cylinder 11 having a rotating shaft 12 and a roller cover 13. The rotating shaft 12 is supported by bearings 14.1 and 14.2 for easy rotation. A device (not shown) for moving the printing roller 10 back and forth acts on the bearing. The surface of the roller can be heated to a temperature adjusted by the electric heating device 15.

The hollow metal cylinder 11 has a rough surface so that the roller cover 13 has good adhesiveness. Roller cover 13
Is cast from silicone rubber without silicone fluid. Rollers with such a cover are, according to the instructions of the inventor, a German company (Messrs. Tampo Print GmbH)
H, Alertshausen) and is available there.

The printing roller described with reference to FIG. 1 is used in the method of the invention described below with reference to FIG.

According to the process shown in FIG. 2, the printing block with hot glue is first heated to a predetermined temperature and then maintained at that temperature. Blythe in the Netherlands
The material manufactured by the company under the product code 64/2511 was used as hot glue. Conventional black matrix and phosphor particles were added to the hot glue in an amount of about 80% by weight of the total. The hot glue printing material thus formed is fluid at a printing block temperature of about 60 ° C.

The printing roller 10 is heated to about 30 ° C., a temperature below the temperature of the printing block. This roller temperature is maintained at a constant temperature within a range of a few degrees like the block temperature. In use, the front panel is supplied to the printing device at ambient temperature, ie, about 20 ° C., and is therefore a few degrees below the printing rollers.

To maintain said temperature conditions, the printing rollers first pass over a particular printing block and then over a front panel located at the same height. The rotation angle of the printing roller is set to a predetermined value before being placed on either the printing block or the front panel, thereby allowing printing of the exact position.

Using a roller cover section of the type described above with a hardness of 40 Shore A, it has been found that a matrix strip having a width of 40 mm can be printed with an accuracy of a few mm.

Although the present invention has been described with reference to specific embodiments thereof, many modifications and changes can be made without departing from the scope of the invention.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a printing roller made of silicone rubber containing no silicone fluid. FIG. 2 is a flowchart of a method for transferring hot glue from a printing block to a front panel of a display device. 10 ... printing roller, 11 ... hollow metal cylinder, 12 ... rotating shaft, 13 ... roller cover.

Continuation of the front page (56) References JP-A-59-81833 (JP, A) JP-A-53-81065 (JP, A) JP-A-S60-242084 (JP, A) JP-A-63-128996 (JP) (A) JP-A-64-48346 (JP, A) JP-A-60-225799 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B41N 10/00 B41N 7/00 B41F 17/00 H01J 9/20

Claims (2)

(57) [Claims] 1. A printing block having a hot-glue printing material heated and made liquid, a printing roller for applying the hot-glue printing material of the printing block to a surface and transferring the same to a pattern support of a display device. The printing roller includes a cover portion made of silicone rubber that does not contain a silicone fluid, and further includes a heating device that heats the surface of the printing roller to a regulated temperature. A transfer device for heating a printing roller so as to maintain the roller at a set temperature several tens of degrees lower than a printing block. 2. A method for transferring a hot-glue printing material from a printing block to a pattern support of a display device using a printing roller, wherein the printing roller includes a cover portion made of silicone rubber containing no silicone fluid. Equipped with a heating device that further heats the surface of the print roller to the adjusted temperature, heats the printing block having the hot glue printing material to a predetermined temperature, turns the hot glue printing material into a liquid state, and holds the temperature, The printing roller is heated by the heating device to maintain the printing roller at a set temperature of several tens of degrees lower than the printing block, and the pattern support of the display device is at an ambient temperature lower than the set temperature of the printing roller. Holding the printing block hot glue printing material on the surface of the printing roller Transfer method of the hot glue printing material, characterized in that for transferring the hot glue printing material in a pattern support the display device from the printing roller.