JPS6216835B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a sleeve cloth that fits over the surface of a water bar roller that supplies moisture to a plate cylinder of an offset printing press.

FIG. 2 shows an example of a water supply system for an offset printing press, in which 1a to 1e are water rod rollers, 2 is a plate cylinder, and 6 is a water tank. Water is supplied to the plate cylinder 2 by the water rod rollers 1a to 1e. A plate film is wound around the plate cylinder 2, and ink is supplied to this film. The film surface is divided into parts that repel water and parts that do not, and the ink gets on the parts that repel water, but does not get on the parts that get wet.This makes printing possible. It is done.

The water rod rollers 1a to 1e are covered with a tube cloth that easily absorbs water, but since the tube cloth is fibrous, fluff easily comes off, and if this fluff adheres to the plate cylinder, it will interfere with the ink transfer. There is a problem in that it causes unevenness and makes the printing untidy.

In order to prevent this problem, Japanese Patent Publication No. 50-33448 discloses a water rod roller which is characterized in that rayon filament is used as the pile yarn and braided into a cylinder shape, and the pile on the cylinder fabric surface is sheared and cut. A tube cloth is presented. Since the pile is shear cut, the surface of this product is smooth and soft like velvet, and it is excellent in that it has the effect of softening the surface of the water rod roller that comes into contact with the plate cylinder. Because of this, the pile threads are cut apart and short within the tissue, making it easy for the pile to fall out.
Since this causes fluff to fall off, the use of long fibers has no particular significance, and there is also the disadvantage that the durability of the sleeve fabric is poor due to the shedding of the pile.

The first object of the present invention is to eliminate these drawbacks of conventional sleeve cloths and provide a sleeve cloth for water rods that has a soft surface, does not shed fluff, is durable, and has good water absorption. .

In order to achieve this purpose, the method adopted in the present invention is to leave the pile of the knitted tube-knit tube fabric with piles on the surface as a loop pile without shearing and cutting, and to crimp the pile yarn. This means using untwisted or very lightly twisted rayon filament yarn that is almost untwisted.

FIG. 1 shows an example of a water rod roller 1 using a sleeve cloth according to the present invention, where 3 is a sleeve cloth, 4 is a loop pile,
5 is a rubber roller.

The pile yarn of the present invention is not an ordinary rayon filament yarn but a crimped rayon filament yarn, so each finely curled fiber is loosely intertwined with each other due to the curl. The yarn is untwisted or almost untwisted, so it is as soft as yarn spun dry and twisted from cotton, and the pile is fuzzy and soft, and because it forms loops, There is volume.

Since the surface of the tube cloth of the present invention is composed of such loop piles, the surface is very soft, and in order to eliminate the hardness of ordinary rayon filament yarn, the loop piles are sheared and cut. However, there is no longer any need for this, and the shearing process is therefore omitted, and most importantly, the pile is not cut by shearing, so the rayon filament is not cut into pieces, but remains as a long fiber and is formed into a loop pile. , so there is no shedding or shedding.
This makes it possible to achieve the object of the present invention, which is to prevent fluff from adhering to the plate cylinder. Furthermore, since the pile of the present invention forms soft loops and has volume, it retains water well and has great durability because the pile does not come off.

Next, the second object of the present invention is to suppress excessive shrinkage of the tube cloth and to have an appropriate shrinkage ability to prevent the diameter of the tube cloth from expanding due to the centrifugal force of rotation of the water rod roller. Our goal is to provide cylindrical cloth.

Conventionally, there has been a strong tendency to use highly shrinkable fibers in the tube cloth in order to prevent the diameter of the tube cloth from expanding and loosening due to the centrifugal force caused by the high speed rotation of the water rod roller. For example, Special Publication No. 47-29649, Special Publication No. 47-29649,
Publication No. 29651 describes non-acetalized PVA fiber, Jikoaki
No. 48-7846 discloses a heat-shrinkable yarn such as Teviron,
Utility Model Publication No. 50-6413 describes a method of using polyvinyl alcohol fibers that are insoluble in water at room temperature and soluble in hot water, but these are all methods for imparting strong shrinkability to tube cloth. It is something. However, when strong shrinkage fibers are used for sleeve fabrics, the following drawbacks have been considered problematic. One of the disadvantages is that the rubber roller used for the water rod roller is damaged due to the hardness caused by the strong contraction of the tube cloth, and the other is that the tube cloth can be damaged by moisture in the air. Since it shrinks, it is extremely inconvenient to handle, as it requires sealed packaging in a cloth tube until it is used in a water stick. Considering this point,
The present invention aims to develop a tube fabric that does not have strong shrinkage but has an appropriate degree of shrinkage that can prevent expansion of the tube fabric diameter due to rotational centrifugal force.

In order to achieve this objective, the present inventor conducted repeated experiments using various usage rates of various fibers regarding the composition of the ground yarn, which has the greatest influence on the shrinkage of the tube cloth. The composition is a combination of cotton yarn and vinylon yarn, and the amount of vinylon fiber used is 20% of the entire ground yarn.
It was concluded that it is appropriate to set the amount to ~60% (weight ratio in an absolutely dry state). Here, an absolutely dry state is a state that does not contain moisture.

The effect of using cotton yarn and vinylon yarn together as the tube fabric yarn is that cotton yarn alone has weak resistance to rotational centrifugal force, causing the tube fabric diameter to expand, but the presence of vinylon yarn strengthens that resistance and increases the tube fabric diameter. It can prevent expansion. By appropriately using vinylon fibers, excessive shrinkage of the tube cloth can be prevented, and damage to the water rod rubber roller caused by the conventional strongly shrinkable tube cloth and inconvenience in handling before use can be avoided. It is.

In the present invention, cotton yarn and vinylon yarn are used together as the base yarn, but if the cotton yarn and vinylon yarn have different counts,
It is not possible to express an appropriate ratio that produces the above-mentioned effects by using the ratio of the number of used parts. Therefore, as mentioned above, we decided to express the actual usage ratio of cotton yarn and vinylon yarn by the ratio of vinylon fiber to the total ground yarn. If the ratio of vinylon fibers to the entire ground yarn is below the lower limit of 20 to 60%, the deterrent force against expansion of the tube fabric diameter against rotational centrifugal force will be too weak, and if the ratio is higher than the upper limit of the above range. , the shrinkage of the tube cloth becomes too strong and the desired effect cannot be obtained. It is optimal to use vinylon fibers in an amount of about 35 to 40% (absolute dry weight ratio) of the entire ground yarn.

Next, one embodiment of the present invention will be described.

Two 20-count cotton threads and one same-count vinylon thread are used as the ground yarn in a drawn pattern, and crimped rayon filament yarn with a very loose twist count of 1 to 3 per meter of twist is used as pile yarn. It is used for knitting into loop pile stockinette tubular knitting using normal pile knitting structure. The proportion of vinylon fiber in the base yarn of this tube cloth is about 35% (bone dry weight ratio), and the shrinkage rate in water is about 5%. When this cylindrical cloth is used by being fitted over the printing water rod roller, it has good water absorption properties and has an excellent humidifying effect on the plate cylinder, and since no fluff falls off, the fluff does not adhere to the plate cylinder, and the surface Because it is soft, it does not damage the plate cylinder and easily fits on the water rod roller, and even when the roller rotates at high speed, there is no loosening due to expansion of the diameter of the tube cloth. Since the roller is covered, there is no damage to the rubber roller, and since it is a loop pile, the pile does not come off and is durable, and there is no need to seal the tube cloth in handling before using it for the water rod roller. It is extremely easy to handle.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway front view of a water rod roller covered with the sleeve cloth of the present invention, and FIG. 2 is a diagram illustrating the use of the water rod roller. 1...Water stick roller, 2...Print cylinder, 3...Top cloth,
4...Loop pile, 5...Rubber roller.

Claims (1)

[Scope of Claims] 1. In a knitted tubular knitted tube fabric having loop piles on the surface, the pile yarn is composed of crimped rayon filament that is untwisted or extremely lightly twisted yarn that is close to untwisted. Features printed water rod tube cloth. 2 In a knitted tubular knitted tube fabric with loop pile on the surface, the pile yarn is composed of crimped rayon filament that is untwisted or extremely lightly twisted yarn that is close to untwisted, and the ground yarn is composed of cotton yarn and vinylon yarn. A sleeve fabric for printing water rods, characterized in that the amount of vinylon fiber used is 20 to 60% (absolute dry weight ratio) of the entire ground yarn.