JPH0261915B2 - - 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 and that holds a base paper attached to the outer surface of the screen.

(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.

FIGS. 3 and 4 show an example of this. FIG. 3 is a cross-sectional view of the drum, and FIG. 4 is an enlarged partial cross-sectional view of the drum, as well as 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.

Note that the reference numeral 17 in FIG. 3 is an inking roller, which remains stationary at the position indicated by the dotted line during normal printing and does not have any effect on the ink 11 in the drum 10; It is used in the state shown by the solid line as a means for forcibly replenishing ink when performing solid printing or when the amount of ink in the drum 10 decreases and uneven printing occurs.

The outline of the mimeograph printing machine has been explained above, and the mimeograph printing machine is used by attaching the base paper 14 to the outer surface of the screen 13 having a mesh structure wound around the surface of the drum 10. The reason for this is that if the base paper is directly attached to the drum surface without using a screen, it will be difficult to hold and fix the base paper, resulting in problems such as poor print density, print unevenness, and poor resolution.

In other words, the purpose of using the screen is to eliminate these problems. In other words, the screen is used to hold and fix the base paper on the drum surface, uniformly disperse the ink (average the ink layer), and ensure that the ink is evenly distributed. This means that it is desired to have functions such as forming an impregnated layer (maintaining ink retention in continuous printing) and improving printing resolution.

By the way, screens made of long fibers of chemical fibers have been widely used in the past.

5 and 6 are views showing a woven fabric made of long fiber yarn material constituting this screen, with FIG. 5 being a plan view and FIG. 6 being a sectional view. Reference numerals 20 are yarn materials obtained by spinning long fibers, which are regularly woven vertically and horizontally to form a woven fabric. A space 21 is created between the threads, and this constitutes a mesh. The screen is made by stacking multiple layers of this woven fabric as required.

In addition, in the past, cotton fibers, which are natural fibers, were sometimes used instead of chemical fibers.

However, a screen composed of such long fibers has a problem in that it lacks the ability to retain the base paper on the drum surface as described above.

In other words, the leading edge of the base paper is mechanically supported by a part of the drum, and the other part is wrapped around the screen facing the screen surface.
Mechanical loads act in many directions. At this time, the screen made of long fibers has a weak holding power for the base paper, so the base paper moves in that direction on the screen surface, causing deformation and, in some cases, being cut.

For example, using this long fiber screen,
When printing with the configuration shown in Figures 3 and 4,
After printing 600 sheets, the base paper stretches by about 2 mm, and from 800 sheets
There is data that shows that the original paper is cut after printing 1000 sheets.

In order to increase the holding power of this screen to the base paper, it is sufficient to increase the frictional force on the surface of the screen.

In this respect, the cotton screen is composed of short fibers, and since the yarn material has naps, the frictional force on the surface of the screen is large, and the holding power to the base paper is superior to that of long fibers.

However, since cotton is a natural fiber, it has inferior water and oil resistance compared to chemical fibers, and the tension of the warp and weft threads that make up the woven fabric is not uniform, resulting in uneven mesh sizes due to long-term use. There was a problem that the durability was inferior.

In order to solve this problem, the present applicant has already constructed a screen using a woven fabric made of raised thread material by processing and spinning chemical fibers into short fibers, and has created a screen with great holding power and excellent durability. provided.

(Problems to be Solved by the Invention) However, the yarn material obtained by spinning these short fibers has raised hairs around it, and therefore, the woven fabric made of this yarn material has raised hairs throughout. This raising reduces the space that makes up the mesh of the screen (woven fabric), which affects the proper ink passing power and dispersion effect during printing, causing problems in that it interferes with the original function of the screen. .

(Object of the Invention) Therefore, the object of the present invention is to provide a screen that has a large holding power to the base paper, is excellent in durability, and in which the nap does not affect the ink passing power or the dispersion effect. It is in.

(Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention provides a screen 13 that is wound around the surface of a drum 10 of a mimeograph machine and that holds a base paper 14 on the outer surface thereof. The screen 13 is formed by applying a raising process to one surface of a woven fabric 1 made of a yarn material 2 spun from long fibers.

(Operation) A means for solving the above-mentioned problems operates as follows.

Since the naps 3... are provided by the napping process only on one surface of the woven fabric 1 constituting the screen, the naps 3... do not reduce the spatial area constituting the mesh 4... and, moreover, have a strong holding power against the base paper. becomes sufficiently large due to this raised hair 3.

(Example) Examples of the present invention will be described below based on the accompanying drawings.

1 and 2 show a woven fabric constituting a screen according to the present invention, FIG. 1 being a partial plan view thereof, and FIG. 2 being a sectional view thereof.

Reference numeral 1 is a woven fabric (Fig. 5, 6
This is a woven fabric obtained by applying a raised finish using stainless steel wire or the like to one surface of the fabric shown in the figure.

The naps 3... provided by this napping process have no directionality and are provided only on the surface on which the original 14 is mounted, so they have a large retention force for the original, and also constitute the mesh 4 of the screen (woven fabric). There is no need to reduce the space area.

In addition to using this woven fabric 1 as a screen, a plurality of other woven fabrics that form an ink-impregnated layer on the back side of the woven fabric 1 may be stacked together and used as a screen.

(Effects of the Invention) As is clear from the above explanation, according to the present invention, the raised naps 3 do not reduce the space area constituting the mesh 4, and therefore good printing is possible and the document can be held. It is possible to provide a screen for a mimeograph printing machine that has the same excellent strength and durability as conventional ones.

In this embodiment, a single-cylinder type mimeograph has been described, but the present invention can be similarly applied to a multi-cylinder type.

[Brief explanation of the drawing]

1 and 2 are diagrams showing the woven fabric constituting the screen according to the present invention, FIG. 1 is a partial plan view thereof, FIG. 2 is a sectional view thereof, and FIG. 3 is a drum of a mimeographing machine. 4 is an enlarged partial cross-sectional view of the drum in FIG. 3, and is a diagram showing the printing operation of a mimeograph printing machine. FIGS. 5 and 6 are long-fiber yarn materials constituting a conventional screen. FIG. 5 is a partial plan view thereof, and FIG. 6 is a sectional view thereof. In the drawings, 1 is a woven fabric (screen), 2... is a thread material, 3... is a nap, 10 is a drum, 13 is a screen, and 14 is a base paper.

Claims (1)

[Claims] 1. A screen that is wrapped around the drum surface of a mimeograph machine and holds base paper attached to the outer surface of the screen, and the screen is constructed by applying a raised finish to at least one side of a woven fabric made of a yarn material spun from long fibers. A screen for a mimeograph printing machine.