JPH057182B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is a method for removing adhering foreign matter such as fragments of dried ink, paper dust from printing paper, hair scraps from water stick rolls, and dust floating in a factory from the plate surface of a printing press, that is, dust. It is related to.

Hitsuki adhering to the plate surface is a cause of the hitskies problem, which causes minute white spots where ink is not transferred to the printing surface of printed matter.The machine must periodically stop during continuous printing to clean the plate surface to remove the hitskis. is necessary.

However, cleaning the plate while stopping the plate not only leads to a decrease in the operating rate, but also causes the cleaning marks left on the plate to completely transfer to the printed matter and disappear from the plate when printing is restarted after cleaning. However, since defective printed matter with the cleaning traces transferred thereto is printed, there is the disadvantage that the printing yield is also lowered.

The Picking Roll is used to remove the pickles that are transferred to printed matter by transferring them to the surface of the roll, and is used in contact with the plate surface at all times or whenever a pickle is discovered, thereby removing the pickles by cleaning the plate surface. This is an attempt to eliminate the inconvenience. Therefore, the picking roll used has a rough surface to which the pickles are more easily transferred than printing paper, such as rolls wrapped with Molton, rubber rolls with chopped short fibers kneaded into the surface, etc.
A method has been proposed in which a roll with fiber fluff on the surface is substituted for part of the inking roll.

However, the use of conventional picking rolls has the following problems.

(1) Kneading the rubber or resin elastomer composition and short fiber pieces hardens the rubber roll, so it is impossible to mix in a large amount of short fiber pieces, and the cutting and polishing of the surface makes it difficult to protrude from the surface. The fiber naps that appear are on the order of microns, less than 1 m/m, and both the rubber roll kneaded with short fiber pieces and the Molton-wrapped roll have a small proportion of the protruding upright fluff on the roll surface, and they tend to adhere during use. Since the lint sticks together with the ink and smoothes the roll surface, a sufficient lint removal effect cannot be expected.

(2) In particular, in the case of rolls wrapped with Molton, which does not stand upright but lies diagonally and has a lot of fluff on the surface that gets entangled with the base fibers, the stickiness that adheres to it during use is thrown onto the fluffy fibers that lie down, along with the ink. It is hard to remove even by washing because it sticks and is hard to remove.
In addition, ink from the previous use remaining after cleaning oozes out during reuse, resulting in defective printed matter being printed at the start of printing due to cleaning and reuse of the picking roll.

(3) Because it is difficult to clean for reuse, it is necessary to stock up on replacement picking rolls, and therefore a special storage space must be provided within the factory.

(4) For rubber rolls kneaded with short fiber pieces,
The rubber or resin elastic body constituting the roll base gradually becomes brittle and its surface becomes cut and polished, making it impossible to reuse it.

(5) The use of a picking roll in place of a part of the inking roll will rub off the ink that remains on the ink-attached handle part of the printing plate even after it has been transferred to the blanket cylinder or printing paper, and eat it out of its outline. Because of this, it is not possible to obtain clear printed matter that follows the outline of the ink-attached handle.

The present invention solves this inconvenience, and provides a surface layer with a pile structure composed of a base structure made of hydrophilic fibers and a surface pile made of hydrophilic and/or oil-repellent fibers with cut ends. The gist of this method is to bring a roll coated with upright pile naps into contact with the plate surface while applying moisture on the front side of the inking roll.

To explain the invention in conjunction with the embodiments shown below, FIG. 1 is a schematic side view of a printing press, in which ink
Ink drawing roll 7, ink kneading roll 8,
8', 8''...and inking rolls 9, 10, 1
1 and 12 to the plate cylinder 13, and is further transferred to the printing paper 15 via the blanket cylinder 14. A water rod roll 19 to which water 18 has been applied via a water wetting roll 16 and a chrome roll 17 is in contact with the plate cylinder 13 to apply moisture to the plate surface. In addition, 20 in the figure is an impression cylinder. The picking roll and the plate cylinder may be such that the tip of the pile lightly touches the plate surface.

According to the conventional example, the picking roll is installed in place of the inking roll 12 that first contacts the printing plate, but in the embodiment of the present invention, the picking roll is installed at a position relative to the rotational direction N of the printing plate rather than the water rod roll 19. Furthermore, it is attached to the front side in contact with the chrome roll 17 and the plate cylinder.

Therefore, the surface of the picking roll 1 is wet with water.

The picking roll 1 in the embodiment consists of a roll base 3 and a cylindrical cover 2 made by a circular knitting machine, as shown in an enlarged view in FIG. The pile 5 is entangled with the base 4 and stands upright on the base 4.

The ground texture is cotton, linen, rayon, acetate,
Hydrophilic fibers such as Kyupura and polyvinyl alcohol (vinylon) are used. In this case, hydrophobic fibers may be mixed in to reinforce the yarn required for weaving and knitting, within a range that does not impede the effects of the present invention. As is clear from the examples of these fibers, in the present invention, "hydrophilic fibers" refer to "hydrophilic fibers" that are easily wetted by water, and aggregates of these fibers, such as threads, fabrics, and webs, become wet and retain absorbed water between the fibers. It does not include nylon, polyester, polyvinyl chloride, polypinylidene chloride, acrylic fibers, etc., which are usually called "hydrophobic fibers".

Among the hydrophilic fibers exemplified above, strong rayon with a high degree of stretching and unacetalized or low-acetalized polyvinyl alcohol fibers particularly absorb moisture and shrink, so the texture of the cylindrical cover 2 as shown in FIG. If the cover 4 is made of these fibers and is fitted into the roll body 3 and then moisturized, the cover 2 will adhere to the roll body 3 due to water absorption and contraction of the ground tissue, which is convenient for manufacturing the picking roll 1. Therefore, for this purpose, it is particularly recommended to use un- or low-acetalized polyvinyl alcohol fibers that exhibit water absorption of 10% or more.

In addition to hydrophilic fibers, fluorine-based synthetic fibers such as oil-repellent fibers such as tetrafluoroethylene (Teflon) fibers can also be used for the pile.

Pile structures made of such a ground weave and pile can be applied to pile fabrics having a total pile yarn denier of 600 to 700 deniers, such as those produced by not only the above-mentioned circular knitting machines but also tricot knitting machines, ratchet knitting machines, moquette looms, towel looms, etc. can be made using a weaving device,
A loop pile fabric in which a pile is formed in a ring shape may be sheared, and the tip of the loop pile may be cut open to be used as a cut pile. It would make it even more effective.

Particular attention should be paid to the thickness of the pile fiber (single yarn denier) and the protruding length of the pile (pile length).
Use 100 denier fibers, more preferably 5 to 10 denier fibers, and set the pile length to 1 to 5 m/
m, preferably around 2 m/m. Because,
Set the single yarn denier to 2 denier or less and reduce the pile length.
When a picking roll of less than 1 m/m is installed in contact with the chrome roll 17 together with the water rod roll 19 as shown in Fig. 1, it is a mere dampening roll with two water rod rolls wrapped with Molton. This is because, like the device, the hitki removal effect cannot be expected, and if the single yarn denier is set to 50 to 100 deniers, the plate surface will easily wear out and the service life will be shortened. This is because the entanglement with the ground tissue is poor and hair removal is likely to occur during handling before attachment to the roll body 3. However, the single yarn denier of the pile fibers must be thicker than the fibers customary for Molton. Further, the thickness and length of the pile are determined relatively and are not essential to the present invention.

Next, the present invention will be explained from the viewpoint of operation and effect.Since many pile fibers on the surface of the picking roll stand upright and are close to each other, the hitki picks as if to pierce between the pile fibers. It transfers to the roll, and in this way, it comes into contact with the hitkey attached to the plate surface and grips it between the pipe fibers that are in close contact with each other, as if to pick it up, and when it overlaps and grips the hitkey, the hitkey that was gripped first is gradually removed from the ground structure. That is, since the hitkey removed from the printing plate is absorbed into the inside of the pile structure by moving to the base side of the pipe, the hitkey removal effect does not deteriorate during the continuous printing process. This absorption effect is achieved by the fact that the pile is made of hydrophilic or oil-repellent fibers, which retain water between the fibers when water is added to them, allowing the pile fibers to stay in a floating state between the pile fibers without adhering to them. This is thought to be due to the fact that in the present invention, not only the pile but also the base structure are hydrophilic fibers, and when wet and hygroscopic, they become oil repellent and repel ink. Therefore, it is easy to clean and remove the hitches that have been transferred and absorbed after printing is completed, and in particular, since the picking roll is in a water-wet state where ink does not adhere, it is difficult to remove the picking roll when changing the ink color. Does not necessarily require replacement or cleaning,
Work such as plate changes and color changes is streamlined.

At the same time, since the pile structure is attached to the roll body in a replaceable manner, there is no need to stock the roll body for replacement, and when it wears out, only the pile structure can be discarded and replaced and the roll body can be reused. The pile structure required for its replacement can be folded and stored, and is less expensive than the roll body, so the implementation of the present invention is extremely economical.

The picking roll 1, which is attached to the front side of the ink roll in a water-wet state, has the function of coating water onto the plate surface in the same way as the water rod roll 17. According to the mounting of the picking roll 1 on the front side of the picking roll 19, the ink 23 which has been transferred to the blanket cylinder 14 and still remains slightly on the ink adhering handle part 22 is removed by contact with the pile tip of the upright picking roll. Even if the ink 2 oozes out from the handle contour to the plate surface area 21, the ink 2 that oozes out due to the water subsequently applied from the water rod roll 19 to the plate surface area 21.
3 is pushed back into the handle contour by surface tension, resulting in a clearer print than before.

Furthermore, since the pile structure 2 wound around the roll body 3 is made of hydrophilic fibers that exhibit water absorption properties, it is formed as a cylindrical cover as shown in FIG. 2, and is simply wrapped around the roll body. Even if the roll body 3 is fitted into the roll body 3 to make a close contact, it will not slip off from the roll body 3 during use, and on the contrary, it will be further tightened by the applied moisture and will tightly adhere to the roll body.

Such water absorption and contraction of the ground structure increases the pile density after weaving and knitting, and also causes the pile fibers to become closer together and stand up to each other, making the fibers stand upright. As a result, the hitkey grasping and absorbing ability is further increased, making hitkey removal even more effective.

The embodiment of the present invention shows a case in which moisture is applied to the picking roll 1 using a dampening device, but this picking roll 1 is made independent from the dampening device and moisture is applied to the picking roll 1 by a spray device or the like. It can also be attached to the front side of the ink roll regardless of whether it is in front or behind the water rod roll, or the contact between the picking roll 1 and the plate cylinder 13 is intermittent. Good too,
Therefore, you can contact them every time you find a hitsky.
The present invention includes these embodiments, and the technical scope of the present invention is not reduced or limited thereby.

[Brief explanation of the drawing]

FIG. 1 is a side view of a printing press according to an embodiment of the invention, FIG. 2 is a partial cross-sectional view of a picking roll according to the invention, and FIG. 3 is a partial perspective view of a printing plate. 1... Picking roll, 2... Pile structure, 3... Roll body, 4... Ground texture, 5... Pile, 9, 10, 11, 12... Inking roll, 13... Plate cylinder, 18...Wed.

Claims (1)

[Scope of Claims] 1. A printing machine equipped with a water rod roll 19 with a fluffy surface that applies moisture 18 to the printing plate on the front side of the inking roll 12 that applies ink 6 to the printing plate, comprising: (a) hydrophilic fibers; (b) The thickness of the hydrophilic or oil-repellent fibers of the surface pile 5 is 5 to 100 denier water stick roll 1
(c) The roll 1 whose surface is covered with a pile structure 2 having a pile length of 1 to 5 mm is thicker than the fibers of the surface fluff of (d) the inking roll 12. Further, on the near side of the water stick roll 19, which is on the near side, while adding moisture to the surface pile 5, (e) bringing it into contact with the plate surface, a method for removing dust on a printing press in a printing press.