JPH055451U - Printing web cooling system - Google Patents

Abstract

(57) [Abstract] [Purpose] The present invention provides a cooling roll capable of effectively preventing "fire wrinkles" generated on a printed web. A cooling device for a printing web provided with a pressing roller that cooperates with a cooling roller to nip the printed web, and a means for supplying dampening water to the pressing roller.

Description

[Detailed description of the device]

[0001]

[Industrial application]

 The present invention relates to a cooling roller for cooling a web of a printing press and an accessory device thereof.

[0002]

[Prior Art]

 FIG. 6 shows the printing, dryer and cooling structure of the printing press. This is an example of a commercial offset press. The web 2 is printed by the printing unit 6, enters the dryer 5, and after drying enters the cooling roller 8. In the dryer 5, the ink solvent is vaporized by the hot air, and then the ink is cooled on the cooling roller 8 to solidify the ink. Then, the web 2 advances to a folding machine (not shown) in the next process.

[0003]

[Problems to be solved by the device]

 The above-mentioned conventional technique has the following problems. (1) "Fire wrinkle" is generated. "Fire wrinkle" is a deformation of unevenness having a pitch of 10 to 20 mm and an amplitude of 0.1 to 0.5 mm, which is generated in the printing portion. “Fire wrinkles” deteriorate the quality of printed matter, and efforts are being made to reduce “fire wrinkles” from both aspects of printing technology and printing machines. (2) The cause of "fire wrinkles" is considered as follows. The amount of moisture evaporating during heating in the dryer 5 is different between the printed portion where the ink is applied to the web 2 and the blank portion where the ink is not applied, and the amount of evaporated water is greater in the blank portion than in the printed portion. is there. This difference in water evaporation causes a difference in the amount of shrinkage between the printed part and the blank part in the web, and this difference causes wrinkles in the printed part. After that, the web 2 is cooled on the cooling roll 8 but is flat on the cooling roll 8 and there is no force to pull the paper in the width direction, so that the web 2 is generated in the dryer 5. The wrinkles of the printed portion remain as wrinkles on the cooling roll 8. At this time, if the ink is solidified by cooling in this state, wrinkles remain due to the binding force of the ink film, resulting in “fire wrinkles”. (3) Up until now, there have been rollers with a groove formed in the entire width of the cooling roller 8, but this has the problem of stains on the printing surface and ink adhesion to the roller due to slippage between the printing surface and the grooves. is there. (4) Further, as shown in FIG. 6, a water jet nozzle 9 is attached, and water from a water supply pump (not shown here) is blown onto the web 2 to reduce the difference in the total amount of water evaporation. However, since it takes only a few minutes for the nozzle 9 to reach the cooling roller 8 and does not sufficiently penetrate into the paper as it is, the amount of shrinkage that causes wrinkles is reduced. It could not be made sufficiently uniform. Also, with this method, large water droplets may locally adhere to the web 2, and in the worst case, paper breakage may occur, and a large amount of water could not be applied, so a sufficient effect can be achieved. could not.

An object of the present invention is to provide a cooling roll capable of effectively preventing “fire wrinkles” generated on a printed web.

[0005]

[Means for Solving the Problems]

 A pressing roller for pressing the web across the cooling roller is provided. A hydrophilic material is used on the surface of the pressing roller to constantly supply water.

[0006]

[Action]

 The printed web is pressed against the cooling roller by means of a moistened pressing roller. A larger amount of water is supplied to the printing web more uniformly than the conventional water jet nozzle, and it is pressed against the cooling roller, so that the wrinkles on the printing web are stretched and the printing web is cooled with the wrinkles stretched. To be done. Therefore, no "fire wrinkles" remain on the printed web.

[0007]

【Example】

 An embodiment of the present invention will be described with reference to FIGS. A pressing roller 3 is installed on the cooling roller 8 so as to sandwich the web 2. The contact point is preferably the point where the web 2 contacts the cooling roller 8. An intermediate roller 10 is in contact with the pressing roller 3, and a water jet nozzle 9 for supplying water is installed between the rollers 3 and 10. At this time, the surfaces of the pressing roller 3 and the intermediate roller 10 are preferably made of a hydrophilic material such as chrome plating. Further, the pressing roller 3 is in contact with the cooling roller 8 with the web 2 interposed between the rollers 3 and 8, but the axial distance is adjusted so that an excessive pressing force is not generated. For this purpose, for example, as shown in FIGS. 2 and 3, a cooling roller chassis 13 holding the shaft of the cooling roller 8 and a pressing roller bearing chassis 15 holding the shaft of the pressing roller 3 are screwed together. It can be realized by tying with and adjusting the relative distance with the adjusting bolt 16.

Next, the operation of this device will be described. As shown in FIG. 4, even if the wrinkle 1 on the printing surface comes under the pressing roller 3, it cannot be passed through because there is no gap between the pressing roller 3 and the cooling roller 8, and the web 2 becomes a roller. At the time of non-constraint before contact, it extends laterally and enters the cooling roller 8. Even if the extended wrinkle 4 is to return to the original shape of the wrinkle next time, the extended wrinkle 4 is pressed against the cooling roller 8 by its own surface pressure and is restrained while being extended due to the frictional force. Wrinkles can be suppressed when the ink solidifies.

In the past, pressing the web 2 over the entire width in this manner had many problems due to an obstacle such as stain on the printing surface. However, in the present invention, the pressing roller 3 having a hydrophilic surface is always used. By supplying water and retaining water, the transfer of oil-based ink to the roller is eliminated, and the problem of contamination can be prevented. Further, the intermediate roller 10 is effective for causing the pressing roller 3 to retain water evenly.

Further, since the water is directly transferred from the pressing roller 3 to the web 2, the water is uniformly transferred as compared with the conventional water absorption on the paper by the nozzle, and there is no fear of the paper being cut off due to local water wetting. The advantage is that a large amount of water can be applied, and the difference in shrinkage amount can be reduced depending on the presence or absence of ink, so it is possible to further suppress the occurrence of “fire wrinkles”. Become.

FIG. 5 shows a second embodiment of the present invention. The difference from the first embodiment is that, when water is supplied to the pressing roller 3, the jet nozzle 9 is abolished and a water tank 12 and a water source roller 11 are installed, and the printing machine has an especially open environment. The operational configuration is the same as that described in the first embodiment, except that it is effective when it is desired to avoid the jetting of water above.

[0012]

[Effect of the device]

 The printing web cooling device according to the present invention has the following effects due to the provision of the pressing roller that cooperates with the cooling roller to hold the printed web, and the means for supplying dampening water to the pressing roller. Have. 1. Since the wrinkles are extended to prevent the wrinkles from entering the cooling roller, and the ink is solidified in this restrained state, "fire wrinkles" can be reduced. 2. Since water is supplied to the pressing roller, the roller surface does not stain the printing surface. 3. The water supplied to the press roller directly moves to the paper surface, and a larger amount of water is retained on the paper more uniformly than with the conventional jet nozzle method. Wa "can be reduced.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a first embodiment of the present invention.

FIG. 2 is a front view showing a mounting portion of a pressing roller.

FIG. 3 is a side view of FIG.

FIG. 4 is a plan view showing wrinkles of a printed web.

FIG. 5 is a configuration diagram of a second embodiment of the present invention.

FIG. 6 is a configuration diagram of a conventional device.

[Explanation of symbols]

 2 Web 3 Pressing roller 5 Dryer 6 Printing unit 8 Cooling roller 9 Water jet nozzle

Claims (1)

Claims for utility model registration: 1. A pressing roller, which cooperates with a cooling roller to nip a printed web, and a means for supplying dampening water to the pressing roller. Printing web cooling system.