JPH0349759B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a screen for a mimeograph machine that is wound around the surface of a plate cylinder (drum) of a mimeograph machine to form an ink-impregnated layer.

(Prior Art) A mimeograph machine is designed so that an appropriate amount of ink is extruded onto printing paper through holes in a base paper, and the ink is transferred thereto.

FIG. 3 shows an enlarged partial cross-sectional view of this drum and is a diagram showing the printing operation.

Reference numeral 10 denotes a cylindrical drum in which an appropriate amount of ink 11 is placed.A large number of drum meshes 12 are perforated on the outer circumferential surface of the drum 10, and a screen having a mesh structure is provided on the outer circumferential surface of the drum 10. 13 is wound, and a base paper 14 is attached to the outer surface of this screen 13.

On the other hand, reference numeral 15 denotes a roller, which is provided so as to press the printing paper 16 through the base paper 14 and the screen 13 onto the surface of the drum 10.

In such a configuration, when the drum 10 is rotated in the direction of arrow A, the roller 15 is rotated in the direction of arrow B due to friction with the base paper 14. At this time, if the printing paper 16 is passed between the drum 10 and the roller 15, the paper 16 will be transferred to the drum 1 by the roller 15.
Pressure is applied to the surface 0, and ink is transferred (printed) onto the surface of the paper 16 only in the holes 14a of the base paper 14.

In this way, the mimeograph machine prints the base paper 14 on the drum 1.
It is used by being attached to the outer surface of a screen 13 having a mesh structure wrapped around the surface of the screen 13. The reason for this is that if the base paper is directly attached to the drum surface without using a screen, problems such as print density, print unevenness, and resolution will deteriorate, and it will be difficult to hold and fix the base paper.

In other words, the purpose of using a screen is to eliminate these problems.In other words, the screen is used to uniformly disperse ink (even the ink layer) and to form a uniform impregnated layer of ink (ink in continuous printing). This means that there is a need for a paper that has functions such as maintaining the holding force (maintaining holding power) and improving printing resolution.

Fig. 4 shows an example of this conventional screen.The screen 20 consists of eight sheets (only part of the upper and lower parts are The mesh 26,...
The roughness of the screen 20 is the same, and therefore the ink retention force on both sides 20a and 20b of the screen 20 is approximately the same.

(Problems to be Solved by the Invention) There are two main types of base paper used in this mimeograph printing machine: thermal base paper and vinyl base paper. Among these, thermal base paper generally has a higher ink transmittance than vinyl base paper due to differences in its manufacturing.

On the other hand, the ink used for mimeograph machines is limited by the printing machine, so when printing on two types of base paper, thermal base paper and vinyl base paper, on the same mimeograph machine, the same In order to transfer the amount of ink and make the print density approximately the same, the ink retention force on the surface of the screen where the base paper is attached must be low when using thermal base paper, and low when using vinyl base paper. On the contrary, it must be made higher.

For this reason, conventionally the screen 20 shown in FIG.
For thermal base paper, the roughness of the mesh is finer to lower the ink retention power, and for vinyl base paper, the roughness of the mesh is increased to increase the ink retention power. These had to be prepared and used by replacing them as appropriate depending on the type of base paper.

Therefore, the purpose of the present invention is that both thermal base paper and vinyl base paper can be used in one screen.
Further, it is an object of the present invention to provide a screen for a mimeograph printing machine, which can perform good printing by making the ink density approximately equal, and can thereby reduce costs.

(Means for Solving the Problems) In order to solve the above problems, the present invention has an impregnated layer for retaining ink, which is wound around the surface of a drum 10 of a mimeograph machine, and a base paper 14 is attached to the outer surface of the drum 10. In the screen 1, one surface 1a of the screen 1 has a large mesh, and the other surface 1b has a small mesh.

(Embodiments) Preferred embodiments of the present invention will be described below based on the accompanying drawings.

FIG. 1 shows a first embodiment of the present invention, in which a screen 1 consists of eight pieces of mesh 2a, which are made by regularly weaving yarn materials 2, . (not limited to 8) woven fabrics, of which the uppermost woven fabric 4 has large meshes 3a,..., the lowermost woven fabric 4 has small meshes 3b,..., and the 6 in between The meshes of the sheets of woven fabric 5, . . . are approximately the same and have a size intermediate between the meshes 3a and 3b. As a result, in the screen 1, the upper surface portion 1a in the figure has a higher ink retention force, while the lower surface portion 1a has a higher ink retention ability.
When using vinyl base paper, attach the vinyl base paper to the larger mesh on the top side, and conversely, when using thermal base paper, attach the thermal base paper to the smaller mesh on the bottom side. By using this method, the same screen can be used regardless of the type of base paper, which is economical.

FIG. 2 is a diagram showing a second embodiment of the present invention,
This screen 6 is made up of eight woven fabrics 8,... having the same mesh size 7,... (not limited to eight pieces), but the uppermost woven fabric 8a has a raised surface 9. The brushed surface 9 increases the ink retention power of the upper surface portion 6a of the screen 6 than the ink retention power of the lower surface portion 6b, and as in the case of the first embodiment, one sheet of The screen allows the use of two types of base paper. Furthermore, in the second embodiment, this raised material has the additional effect of reliably holding the vinyl base paper and preventing the vinyl base paper from being stretched or cut.

It should be noted that the present invention is not limited to the embodiments; for example, the ink retention force may be changed by changing the thickness of the thread material on one side and the other side of the screen. In this case, the size of the meshes of the uppermost and lowermost surfaces are all the same, but this may be configured to gradually change from the uppermost surface to the lowermost surface.Of course, the number of woven cloths making up the screen can also be changed. In the example, there are eight sheets, but the number is not limited to this. For example, in the case of the first example, there may be only two sheets, the uppermost surface and the lowermost surface, and furthermore, in the second example, only one side is brushed. It is also possible to use only one piece of woven fabric.

(Effects of the Invention) As is clear from the above description, according to the present invention, good printing can be achieved by making the ink density approximately equal on both thermal base paper and vinyl base paper using one screen. It is possible to provide an economical screen for a mimeograph machine.

Furthermore, according to the second embodiment of the present invention, since the raised surface is provided on one side of the screen, the vinyl base paper can be held securely and the vinyl base paper can be prevented from being stretched or cut. .

[Brief explanation of drawings]

Fig. 1 is a diagram showing a first embodiment of the present invention, Fig. 2 is a diagram showing a second embodiment, Fig. 3 is an enlarged partial cross-sectional view of the tram portion of a mimeograph printing machine, and Fig. 4 is a conventional example. FIG. And in the drawing, 1, 6, 20 are screens,
2 and 21 are thread materials, 3,..., 7,..., 26,... are meshes, and 5,..., 8,..., 25,... are woven fabrics.

Claims (1)

[Scope of Claims] 1. A screen having an impregnated layer for retaining ink, wound around the drum surface of a mimeograph printing machine, and having a base paper attached to the outer surface thereof, wherein one side of the screen has a large mesh; A screen for a mimeograph printing machine, characterized in that the other side has a small mesh. 2. The screen for a mimeograph printing machine according to claim 1, wherein one surface of the screen is brushed.