JPH0576920B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a printing water rod sleeve that fits over the surface of a water rod roller that supplies water to a plate cylinder of an offset printing machine.

(b) Conventional technology The requirements for printing water rod cylinder cloth are that it should be able to supply sufficient moisture to the plate cylinder, be easy to fit onto the water rod roller, and be able to shrink in water after being fitted. For example, the water rod should be in close contact with the roller surface. In order to meet these requirements, conventional sleeve fabrics for printed water rods are mainly knitted tube fabrics with piles on the surface, and the base threads are yarns that exhibit shrinkage in water. It was getting worse. These conventional examples are described in the following patent publications and utility model publications.
Jitko No. 34-2215, Jitko No. 34-16010, Special Kosho
No. 47-29649, Special Publication No. 47-29651, Actual Publication No. 48-
7846, Special Publication No. 50-5089, Actual Publication No. 50-6413,
Patent Publication No. 50-33448, Publication No. 41353-1983, and Publication No. 16835-1982.

(C) Problems to be Solved by the Invention In a knitted tube-knitted sleeve fabric for a printed water rod that has piles on its surface, if a thread that shrinks in water is used as the ground thread, the tube fabric will shrink in the circumferential direction. Not only does it contract in the water rod roller, but it also contracts in the length direction, shortening the tube cloth. As a result, unless a tube cloth that is considerably longer than the water rod roller is used, the tube cloth may become shorter and the roller surfaces at both ends of the water rod roller may be exposed. This will be a problem if it is not possible to use a long tube cloth with a . In addition, the sleeve cloth that tightly tightens the water rod roller in the circumferential direction gradually contracts in the longitudinal direction during high-speed rotation, causing wear on the rubber surfaces at both ends of the roller, causing the water rod roller to tighten. Shorten lifespan.

In view of the above problems, the present invention aims to prevent the tube cloth from shrinking in the length direction and becoming short.

(d) Means for Solving the Problems To describe the means adopted by the present invention using illustrative drawings, in the stockinette tube-knit tube fabric 1 having piles 2 on the surface, water-absorbing yarn such as rayon yarn is used. The knitting structure of the tubular fabric is formed by the pile yarn 3 made of a yarn with a very small shrinkage rate in water such as cotton yarn, and the ground yarn 4 made of a yarn with a very small shrinkage rate in water such as cotton yarn. A strongly shrinkable vinylon filament yarn is used, and the splint thread 5 is inserted into the knitting structure of the tube fabric 1 while it is being formed, as shown in FIG. Wrap it around the entire length in the length direction. Furthermore, a strongly shrinkable vinylon filament yarn with an extremely high shrinkage rate in water is used as a tying thread, and as shown in FIG. Then, both ends of the tube cloth 1 are sewn with an overlock sewing machine, and the sewing thread 7 is used to secure the tube cloth 1 to the binding thread 6.

In the above, the underwater shrinkage rate refers to the degree of shrinkage caused by immersion in water.

(e) Effect In a pile-knit tube fabric made of pile yarn and ground yarn, the pile yarn is slack due to the formation of the pile, so it does not participate in the shrinkage of the tube fabric. It is exclusively the ground yarn that takes part in the shrinkage of the tube cloth. By the way, since the ground yarn in the present invention is made of a yarn such as cotton yarn that has an extremely small shrinkage rate in water, the shrinkage of the tube cloth due to this yarn is extremely small both in the circumferential direction and in the length direction. It does not come in close contact with the roller. Therefore, the present invention uses strongly shrinkable vinylon filament yarn, which has a much higher underwater shrinkage rate than the ground yarn, as a plating yarn, and uses a circular pattern to prevent the plating yarn from separating into the knitting structure during the formation of the tube fabric. Since it was inserted in the circumferential direction and wound around the entire length in the longitudinal direction, the tube cloth contracted strongly in the circumferential direction due to the contraction of the splint threads, and it came into close contact with the water rod roller. The shrinkage in the longitudinal direction of the tube fabric is extremely small because it is caused only by the shrinkage of the base yarn, which has an extremely low shrinkage rate in water.

The above action prevents the water rod roller surface from being exposed due to shortening of the tube cloth, but in order to further ensure this effect, the present invention separately uses strongly shrinkable vinylon filament yarn with an extremely high shrinkage rate in water. A method was also adopted in which the tying thread was used as a tying thread, and the tying thread was endlessly wound around both ends of the cylindrical fabric after being created, and then fixed to the cylindrical fabric using an overlock sewing machine. The vinylon filament thread used earlier as the splint thread is
The tube cloth is loosened a little by knitting without removing it from the knitting machine, but the vinylon filament yarn used later as a tying thread shrinks the tube cloth diameter more than the plating yarn in water because there is no slack due to the knitting. This acts to bind the tube cloth at both edges. By tying the cylindrical cloth slightly beyond both ends of the water rod roller, shortening of the cylindrical cloth and exposure of the surface of the water rod roller due to the shortening of the cylindrical cloth is reliably prevented.

In addition, since both ends of the plating thread are free without being organized with the knitting threads of the tube cloth, the positional relationship with the tube cloth is unstable. However, by sewing both ends, the plint thread is fixed to the tube cloth. and can be stabilized.

(F) Example Using three strands of 250 denier rayon filament yarn crimped to pile yarn,
A cylindrical loop pile cloth is knitted using a tube knitting machine using three strands of 20th cotton yarn as the ground yarn. Separately, using a device attached to a knitting machine, one 650 denier strongly shrinkable vinylon filament yarn was used, and as shown in Figure 2, during the knitting process, one needle was alternately placed in the circumferential direction so as not to form a knitting structure. While inserting it into the knitting structure, wrap it around the entire length of the tube fabric. The vinylon filament yarn has an underwater shrinkage rate of about 60% in its free state. When the cylindrical cloth produced as described above is used for a printing water rod, the cylindrical cloth contracts strongly in the circumferential direction and comes into close contact with the water rod roller, but the shrinkage in the length direction is extremely small.

Eight strands of 650 denier strongly shrinkable vinylon filament yarn are wound around both ends of the tube fabric and fixed to the tube fabric using an overlock sewing machine.
Both ends of the wrapped vinylon filament thread are
Fix by an appropriate method such as sandwiching and pressing with small metal plates. When the cylindrical cloth made by this method is fitted onto the water rod roller and used with both edges of the cylindrical cloth slightly protruding from the water rod roller, both edges of the cylindrical cloth are covered with vinylon filament wrapped around the water rod roller. Since the yarn is bound by strong contraction, the roller surfaces at both ends of the water rod roller are reliably prevented from being exposed.

(G) Effects of the Invention The pile-knit printed hydrogen sleeve fabric of the present invention contracts strongly in the circumferential direction due to the above-mentioned action of the base thread and the splint thread, but the shrinkage in the length direction is extremely small. If the tube cloth is fitted longer than the water rod roller, the tube cloth will stick tightly to the water rod roller underwater, and even after use over time, the roller surfaces at both ends of the water rod roller will be exposed. There is no risk of abrasion of the rubber on the surface of the water bar roller, which is likely to occur due to shrinkage of the sleeve cloth in the longitudinal direction. In addition, since the pile yarn is made of water-based yarn, it meets the water content requirements for printing water rods.

Furthermore, by fixing the tying threads to both ends of the tube cloth in the manner described above, the effect of preventing the roller surface of the water rod roller from being exposed becomes even more reliable. and,
Since this tying thread automatically shrinks when soaked in water, the unsightliness and poor workability of the conventional method of tying both ends of the tube cloth with kite string or the like after fitting the tube cloth can be improved.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway front view of a printed water rod covered with the sleeve cloth of the present invention, FIG. 2 is a diagram showing the structure of the sleeve cloth of the present invention, and FIG. 3 is a diagram showing another example of the sleeve cloth of the present invention. FIG. 1... Tube cloth, 2... Pile, 3... Pile thread,
4... ground thread, 5... splicing thread, 6... binding thread, 7...
...Sewing thread, 8...Printing water rod roller.

Claims (1)

[Claims] 1. In knitted tubular knitted tubular fabrics with piles on the surface, the knitting structure of the tubular fabric is created using pile yarns made of water-absorbing yarns such as rayon yarns and ground yarns made of yarns with extremely low shrinkage in water such as cotton yarns. In addition, a strongly shrinkable vinylon filament yarn, which has a much higher shrinkage rate in water than the ground yarn, is used as a splint thread, and this splint thread is inserted into the knitting structure during the formation of the tube fabric so as not to separate. Both ends of the tube cloth were created by winding it around the circumference of the tube cloth over its entire length in the longitudinal direction, and then using strong shrink vinylon filament yarn with an extremely high shrinkage rate in water as a tying thread. Wrap this tying thread around the edge and secure both ends to make it endless.
1. A sleeve cloth for a printed water rod, characterized in that both ends of the sleeve cloth are machined with an overlock, and the sewing thread is used to secure the binding thread to the sleeve cloth.