JPS5920670A - Cylindrical cover for water duct roll of printer - Google Patents

Abstract

PURPOSE:To obtain a cylindrical cover free of twisting, convolution, and reversal of yarns between the surface and back of knitted loops using a knitted loop woven in such a way that any one of two kinds of yarns appears either on the surface side or the back side. CONSTITUTION:A knitted loop 1 consisting of at least two kinds of a water- shrink yarn A and a hydrophilic yarn B constituting the surface and back sides is produced by weaving the two yarns A and B concurrently in such a way that the two yarns A and B are each supplid to knitting needles 6 from two yarn supply ports 4 and 5 provided to the feeder 3 of a circular knitting machine. The two kinds of the yarns A and B, therefore, can be knitted by being completely divided into the surface and back layers.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cylindrical cover for a water duct roll that draws and supplies water to a chrome roll in a dampening device for a printing press.

Conventionally, water duct rolls have been made with cylindrical pile knits, that is, Molton, knitted with a circular knitting machine.As a method for ensuring the attachment of the Molton to the roll, the inventor of the present application has proposed 47-29651. The technique disclosed in the % Distribution 50-33448, ie, the method of knitting water-shrinkable fibers into Molton, has been adopted.

However, the Molton that has been conventionally used for water duct rolls has raised piles to which ink easily adheres, and in fact, ink is transferred and adhered from the plate surface to the water duct roll via the Suishin roll and the chrome roll. Ink easily adheres to the pile of the water duct roll, causing uneven water supply from the water duct roll to the chrome roll, which in turn causes printing defects.

The present invention solves this problem, and the water duct roll does not directly touch the plate surface, so the pile of the water duct roll that avoids the wear of the plate surface, as in the case of Molton, which generally comes into direct contact with the plate surface, is designed to solve this problem. It was completed based on the knowledge that water duct rolls are not necessarily necessary for water duct rolls, and on the contrary, water duct rolls without piles do not cause water transfer spots due to ink adhesion. and hydrophilic yarn B are aligned to form a cylindrical shape K using a circular machine so as to form a fine loop 1 without forming pile naps.
It is a cover 2 made with IM, one of the two types of threads appears on the surface and the other appears on the tatami surface, and the two types of threads on the front and back are twisted or twisted between the front and back of the fine loop. Or, it is characterized by being easily reversed.

As the water-shrinkable yarn, strong rayon yarn or non-acetalized polyvinyl alcohol yarn is used, and as the hydrophilic yarn, ordinary rayon, cotton, cupra, etc. are used. However,
Hydrophilic yarns that absorb moisture easily, such as rayon and cotton, generally exhibit water-shrinking properties, and water-shrinkable yarns exhibit hydrophilic properties that absorb moisture and become wet with water, and the above-mentioned yarns are water-shrinkable yarns. It can also be used as a hydrophilic yarn.

It is desirable to use threads that appear on the back side after knitting, which have a higher water shrinkage rate than the threads that appear on the front side. For the side threads, it is better to use strong rayon or non-acetalized polyvinyl alcohol thread, which shrinks even more in water. Furthermore, the material of the thread used in this manner does not necessarily have to be a single material, and may be a combination of two materials, such as cotton and rayon.

In the cylindrical cover according to the present invention, the bipolar threads that are aligned to form a stitch loop are completely separated into front and back layers, and their appearance is schematically shown in FIGS. 2 and 3. The gloss and hue of the front and back sides will be different. 2 and 3 illustrate the case where the cylindrical cover is made of Tenkasa knitted structure, but the knitted structure itself is an essential element in the present invention, and rubber knitted structure or A cylindrical cover can be knitted using a pearl knit structure and a nine-ply knit structure.

Stitch loop 1 of two kinds of yarns arranged on the front and back sides like this
As shown in Fig. 4, two yarn feeders 4 and 5 are provided above and below in the feeder 3 of the circular knitting machine, and the two types of yarns A and B are aligned from the respective yarn feeders to the knitting needles 6. By feeding the yarn at the same time, it is possible to knit from K.

As is clear from Figure 4, if the feeder is provided with three yarn feeders and three types of yarn are fed from each yarn feeder, another type of yarn will be sandwiched between the two types of yarn on the front and back sides, and the front and back will be completed. Therefore, in the practice of the present invention, it is possible to knit by appropriately adding other yarns necessary for reinforcement to the yarns on the front and back sides. It is also possible to set the thickness of the yarns of the front and back stitch loops by feeding a plurality of yarns A and/or B from each or one of the yarns 5 and 5.

Therefore, as is clear, according to the present invention, the surface of the cylindrical hook (-) is smooth and uniform, with little twisting of the thread between the front and back of the stitch loops, and there is no risk of slipping out like the conventionally used Molton. Because there is no pile, there is no adhesion of ink from the chrome roll, and therefore there is no uneven water supply to the chrome roll, and it has excellent strength and dimensional stability, especially for the threads appearing on the back side and the threads appearing on the front side. It is possible to obtain a cylindrical cover which is coated and is not subjected to contact wear by the chrome roll, and therefore has excellent durability.

Next, the present invention will be specifically explained by comparing the physical properties of the cover between an embodiment of the present invention, a comparative example, and a conventional example.

Example C) Cylinder diameter: 88. The feeder of a circular knitting machine with 180 needles is equipped with two yarn feeders, and 65 needles are fed from each yarn feeder.
() A denier water-shrinkable vinylon filament yarn is used as the front side yarn, and a 900 denier rayon filament yarn is fed as the back side yarn at the same time, so that only the vinylon filament yarn appears on the front side and only the rayon filament yarn appears on the back side.A circular knit cylindrical cover. I made it.

C Comparative Example) In the circular knitting machine used in the example, the two types of yarns used in the example were fed from the same yarn feeder to create a circular knit cylindrical cover.

(Conventional example) Cylinder diameter 88.9%, sinker and number of needles 120
In this circular knitting machine, a cylindrical molton with pile napped is made using 9()0 denier rayon filament yarn as the pile yarn and F150 denier water-shrinkable vinylon filament yarn as the pongee (shaft) yarn.

The covers according to the above Examples, Comparative Examples, and Conventional Examples were attached to a water duct roll (roll diameter e, o %□) of an offset printing machine manufactured by Komori Printing Machinery KK (model 22 Corcony) for trial use. The results shown in the table were obtained.

table

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a cylindrical cover according to an embodiment of the present invention, and FIG.
The figure is a partial front view of the cylindrical cover shown in FIG. 1, FIG. 3 is a partial back view of the cylindrical cover shown in FIG. 1, and FIG. FIG. 3 is a front view schematically showing the section. l... Stitch loop 3... Feeder 4.5... Yarn feeder 6... Knitting needles A, B... Yarn patent applicant Techno Roll Co., Ltd. Kakihana - Authorized agent Patent attorney (8189) Chiba Shigeo

Claims (1)

[Claims] A cylindrical cover knitted on a circular knitting machine in which at least two types of yarn, a water-shrinkable yarn and a hydrophilic yarn, are aligned to form a stitch loop, one of the two types of yarn appearing on the front side. A cylindrical cover for a water duct roll of a printing press, characterized in that the other appears on the back side and there is no twisting, twisting, or reversal of the two types of yarns between the two types of yarns connected to the front and back sides of the stitch loop.