JPH11170476A - Dampening cylinder for offset printer dampening roller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dampening cylinder for an offset printer dampening roller having excellent uniformity and stability of water supply in the case of using for a long period with small fault due to generation of fiber chips. SOLUTION: In the dampening cylinder 1 made of a cylindrical pile knitted ground mounted to cover dampening roller 3 of an offset printer, strands made of water shrinkable fiber as ground yarns are used, as yarns for constituting a pipe part, strands made of cellulose long fiber are used. And, the pipe part is constituted by two or more cellulose long fiber strands, and at least one of the long fiber strands is twisted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water rod for an offset printing press used by being mounted on an outer layer portion of a water rod roller which comes into face-to-face contact with a plate cylinder of an offset printing press and supplies water without interruption to the plate cylinder. The present invention relates to a humidifying cylinder for a roller.

[0002]

2. Description of the Related Art Conventionally, as a humidifying cylinder for a water rod roller of an offset printing press, a vinylon yarn that contracts by immersion in water is used as an inner ground structure yarn, and a yarn forming an outer humidifying pile portion. It is known that a filament or spun yarn of a cellulosic fiber such as rayon, cupra, and cotton is tubular-knitted as it is.

As a characteristic of the pile structure, it is necessary that a constant amount of water can be uniformly and stably supplied to the roller surface without falling off of the material, and therefore, the state of contact with the roller and the rotation thereof is always stable. The current products have been used in the market without great improvement for several years for such required quality.

[0004]

As described above, in the prior art, filaments or spun yarns of cellulosic fibers such as rayon, cupra and cotton have been used in the pile portion, which maintain water supply and water retention. Used to However, if the pile part is formed of a spun yarn such as cotton or rayon, when the humidifying cylinder is attached to the water bar roller of the offset printing machine, the fiber waste inside the humidifying cylinder moves to the roller, It becomes mixed with the printing ink, impairs printing performance, requires maintenance and adjustment after installation, reduces efficiency, and consequently increases costs. In other words, the natural fiber cotton has a variable fiber length and is liable to generate fiber debris. Therefore, the fiber is used after sintering after spinning. However, the amount of fiber falling off the humidifying cylinder cannot be eliminated. In addition, scouring and bleaching is required to remove the oils and fats to ensure hydrophilicity, resulting in an increase in cost. In the case of non-twisted long fibers, when used as loop knitting, there is little volume, so there is a problem in the shape of the surface of Molton mesh, and there is a problem that water does not move evenly. As a result, the pile at the contact portion of the roller is rubbed in a certain direction, and is easily worn. For this reason, there are products that are used by shearing the loops and using them. Furthermore, after braiding with a loop pile using cellulosic fiber filaments, shearing, suppressing pile cracking, and a humidifying cylinder designed to maintain water supply, the contact pressure is proportional to the use time. It is necessary to correct the condition and readjust the condition again, and there is a problem that the ink tends to settle down and adhere to the base of the fabric, thereby deteriorating the water supply balance and impairing the printing performance.

[0005] The present invention has been made in view of such circumstances, and offset printing which has less printing defects due to generation of fiber debris and has excellent uniformity and stability of water supply even for long-term use. It is an object of the present invention to provide a humidifying cylinder for a water rod roller.

[0006]

Means for Solving the Problems The present inventors have found that by increasing the tip area of the pile portion on the surface of the humidifying cylinder, it has been found that stable water retention and water supply performance can be imparted. The present inventors have found that the object can be achieved by using two or more strips and using the twisting torque, and have reached the present invention.

That is, the present invention relates to a tubular pile knitted fabric using a yarn made of a water-shrinkable fiber as a ground yarn and a yarn made of a cellulose-based long fiber as a yarn constituting a pile portion. The pile portion is composed of two or more cellulosic long fiber yarns, and at least one of the cellulosic long fiber yarns is twisted. Further, the present invention has a feature that at least one of the yarns composed of cellulosic long fibers constituting the pile portion is twisted in the same direction having a twist number difference of 10% or more. The gist of the present invention is that at least one of the yarns composed of cellulosic long fibers constituting the pile portion is twisted in the opposite direction to the other yarns.

The cellulosic long fibers used in the pile portion of the humidifying cylinder for a water bar roller of the offset printing press of the present invention are cellulosic regenerated fibers such as rayon and cupra, and solvent-spun cellulosic fibers such as lyocell.
The total fineness of the yarn constituting the pile is 400 to 15
00 denier is preferred. If the total fineness of the yarn constituting the pile portion is less than 400 denier, when used as a humidifying cylinder for a water rod roller of an offset printing machine, the density of the pile portion on the surface becomes coarse, the volume feeling is small, and the water retention is poor. Become. Further, when the total fineness of the yarn constituting the pile portion exceeds 1500 denier, when knitting by tubular knitting, fluff is likely to occur, causing poor knitting and possibly causing yarn breakage. . The total fineness of the yarn constituting the pile portion is more preferably 500 to 1000 denier.

The pile portion of the humidifying cylinder of the present invention is composed of two or more cellulosic long fiber yarns, and it is required that at least one of the cellulosic long fiber yarns is twisted. The number of twists is 50 turns / m to 150 turns / m
Is good. When the number of twists is less than 50 turns / m, the torque is reduced, the pile is less deformed, and it is difficult to contribute to the improvement of the tip area of the pile. On the other hand, when the number of twists exceeds 150 turns / m, the torque of the yarn is too strong, which may cause yarn breakage during knitting. The number of twists is 80 turns / m to 100 turns / m
Is more preferred.

[0010] Further, as a combination of twisting directions,
First, there is a combination in the same direction. In this case, it is required that at least one of the yarns has a twist number difference of 10% or more. When the difference in the number of twists is less than 10%, deformation and kinking of the pile tip are small, and may not contribute to the improvement of the pile tip area. This difference in twist number is preferably 20% or more.

Further, the pile portion of the humidifying cylinder of the present invention is required that at least one of the yarns composed of cellulosic long fibers is twisted in the opposite direction to the other yarns. In the case of such a combination of twists in different directions, twisting in the S direction and the Z direction is performed within the range of the appropriate number of twists of 50 turns / m to 150 turns / m. In this case, since the generated torque is in the opposite direction, the deformation of the pile becomes remarkable, which is effective in increasing the area of the tip of the pile.
The number of twists may be appropriately set and combined.

As described above, the humidifying cylinder for a water rod roller of an offset printing machine according to the present invention uses a yarn made of water-shrinkable fiber as a ground yarn and a yarn made of cellulosic long fiber as a yarn constituting a pile portion. The pile portion is composed of two or more cellulosic long fiber yarns, and at least one of the cellulosic long fiber yarns is twisted. At least one of the cellulosic long fibers constituting the pile portion is twisted in the same direction with a twist number difference of 10% or more, and further comprises the cellulosic long fibers constituting the pile portion. Wherein at least one of the yarns is twisted in the opposite direction to the other yarns, and a yarn made of cellulosic long fiber is used for the pile portion, and a water-shrinkable fiber such as a water-shrinkable vinylon is used as a ground yarn. Used as As a result of manufacturing a circular knitted product with a double structure, the deformation of the pile tip becomes remarkable, the tip area of the pile can be increased, the volume can be increased, uniform water absorption and water retention can be ensured, and the pressure balance is good. It is possible to provide a humidifying cylinder for a water rod roller which is an excellent offset printing press that satisfies the quality characteristics required for the humidifying cylinder.
The same result is obtained whether the water-shrinkable fibers are short fibers or long fibers.

FIG. 1 shows a humidifying cylinder for a water rod roller of an offset printing press according to the present invention, and FIG. 2 shows a state where the humidifying cylinder is mounted on a water rod roller. In the figure, reference numeral 1 denotes a humidifying cylinder provided with a pile portion 2 on its surface, and 3 denotes a water rod roller on which the humidifying cylinder 1 is mounted.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be specifically described below. Example 1 Using a 14 gauge sinker pile circular knitting machine, two water-shrinkable vinylon # 20 single yarns were aligned and used as ground yarn, and three 120-denier cupra long fiber yarns were twisted as yarn constituting a pile portion. (100 times / m in the S direction) and two 120-denier untwisted cupra long fiber yarns were simultaneously supplied to knit a tubular pile knitted fabric. This tubular pile knitted fabric was cut into a predetermined length and used as a humidifying cylinder for a water rod roller of an offset printing press.

Example 2 In Example 1, the yarn constituting the pile portion was 120
Instead of using three deniers with three twists (S direction 100 times / m) and two 120 deniers untwisted,
Twisted 120 denier (100 turns / m in S direction) and two 120 deniers (80 turns / m in S direction)
It is the same as Example 1 except that the above-mentioned one is used.

Example 3 In Example 1, the yarn constituting the pile portion was 120
Instead of using three deniers with three twists (S direction 100 times / m) and two 120 deniers untwisted,
Twisted 120 denier (100 times / m in S direction) and three 120 deniers (100 times / direction in Z direction)
m) is the same as in Example 1 except that the above-mentioned one is used.

Example 4 A 14 gauge sinker pile circular knitting machine was used in which two water-shrinkable vinylon # 20 single yarns were aligned and used as ground yarn, and 100 denier cupra filament yarn was used as the yarn constituting the pile portion. This ply twist (100 times / m in S direction) and two 100-denier cupra filament fibers were plied (80 times in S direction /
m) and two cupra filament 100-denier non-twisted yarns were simultaneously supplied to knit a tubular pile knitted fabric. This tubular pile knitted fabric was cut into a predetermined length and used as a humidifying cylinder for a water rod roller of an offset printing press.

Example 5 In Example 4, 100 yarns were used as the yarn constituting the pile portion.
Instead of using two deniers with two twists (S direction 100 times / m), two deniers with 100 deniers (S direction 80 times / m), and 100 denier untwisted ones, Twist 100 denier (100 times in S direction /
m) and two deniers of 100 denier (Z direction 80
Times / m) and 100 deniers are twisted together (Z
Example 4 is the same as Example 4 except that the number of times (direction 70 times / m) is used.

Example 6 In Example 4, 100 yarns were used as the yarn constituting the pile portion.
Instead of using two deniers with two twists (S direction 100 times / m), two deniers with 100 deniers (S direction 80 times / m), and 100 denier untwisted ones, Twist 100 denier (100 times in S direction /
m) and two deniers of 100 denier (Z direction 10
0 times / m) and 100 denier untwisted 2
It is the same as Example 4 except that a book is used.

Example 7 A 14 gauge sinker pile circular knitting machine uses two water-shrinkable vinylon # 20 single yarns as ground yarns in parallel and uses a solvent-spun cellulose-based filament yarn 1 as a yarn constituting a pile portion.
Twisted 20 deniers (100 turns / m in S direction) and two 120 deniers (100 turns / m in the Z direction)
The knitted fabrics were aligned and supplied at the same time to knit a tubular pile knitted fabric. This tubular pile knitted fabric was cut into a predetermined length and used as a humidifying cylinder for a water rod roller of an offset printing press.

Comparative Example 1 Using a 14 gauge sinker pile circular knitting machine, two water-shrinkable vinylon # 20 single yarns were aligned and used as ground yarns, and five cupra filaments 120 denier were drawn as yarns constituting a pile portion. They were supplied together at the same time to knit a tubular pile knitted fabric. This tubular pile knitted fabric was cut into a predetermined length and used as a humidifying cylinder for a water rod roller of an offset printing press.

Table 1 shows the evaluation results of Examples 1 to 6 and Comparative Example 1.

[0023]

[Table 1]

From Table 1, it can be seen that the humidifying cylinders for the water bar rollers of the offset printing machines according to Examples 1 to 5 and 7 have good knitting properties, and also have excellent water retention, durability and printability. . Further, the humidifying cylinder for the water bar roller of the offset printing press according to Example 6 is slightly inferior in knitting property, but also excellent in water retention and printability. The humidifying cylinder for the water bar roller of the offset printing press according to Comparative Example 1 has fluff, and further has poor durability and printability.

[0025]

As described above, the humidifying cylinder according to the present invention has a large pile tip area, can uniformly absorb water, and has a voluminous feel. Therefore, water retention can be ensured, and the pressure resistance balance is improved. As a result of performing offset printing using the cylinder, stable and uniform printing can be efficiently performed, and the replacement time can be extended. This is because, compared to conventional products, there is a sense of volume, the wet condition is stable, there is little settling, constant water can be supplied, and the pressure balance between the contacting rollers is uniform, This is because a certain clearance can be maintained for a long period against stresses such as compression, shear, and torsion.

[Brief description of the drawings]

FIG. 1 is a perspective view of a humidifying cylinder for a water bar roller of an offset printing press according to the present invention.

FIG. 2 is a partially cutaway perspective view of a water stick roller equipped with the humidifying cylinder.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Humidifying cylinder 2 Pile part 3 Water rod roller

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yoshimasa Ito 4-3-1 Kutarocho, Chuo-ku, Osaka-shi, Osaka Unitika Technos Osaka Office

Claims (3)

[Claims] 1. A tubular pile knitted fabric using a yarn made of a water-shrinkable fiber as a ground yarn and using a yarn made of a cellulosic long fiber as a yarn constituting a pile portion, wherein the pile portion is A humidifying cylinder for a water rod roller of an offset printing press, comprising at least two cellulosic long fiber yarns, wherein at least one of the cellulosic long fiber yarns is twisted. 2. The method according to claim 1, wherein at least one of the yarns comprising the cellulose-based filament constituting the pile portion is twisted in the same direction having a twist number difference of 10% or more. Humidifying cylinder for offset printing press water bar roller. 3. The offset printing press water rod according to claim 1, wherein at least one of the yarns composed of cellulosic long fibers constituting the pile portion is twisted in the opposite direction to the other yarns. Humidifier for roller.