JPH01148897A - Paper surface polishing method - Google Patents

Abstract

PURPOSE: To provide a polishing method of paper surface capable of speeding up coating rate by feeding a polishing coating material composed of a resin containing an aqueous or middle-high boiling point organic solvent as a base to a screen coater. CONSTITUTION: A paper feeder 1 for automatically feeding a sheet paper to be polished, a screen coater device 13, a drier 15 and polishing device 24 are installed in series. A polishing coating material for screen composed of a resin containing an aqueous or middle or high boiling point organic solvent as a base is fed to the screen coater device 13. Polyvinyl chloride, polyacetic acid vinyl ester, acrylic acid, urethane resin, etc., is exemplified as the resin. The resin is added to a middle-high boiling point organic solvent or the resin in a form dissolved in water is added to an aqueous base or the resin is emulsified into an aqueous base by using a surfactant to prepare a polishing coating material for screen.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a method of partially polishing a paper surface using a screen coater device.

(Prior Art) When making cans by pasting together the edges of paper, high-speed can making with glue is possible by applying glue to the paper surface by removing only the processed areas and performing a polishing treatment. In addition, if necessary, in order to facilitate the printing of numbering such as the date of manufacture, the surface may be treated to remove such portions, or a partially glossy design may be applied to the surface. Furthermore, the need for partial ejection processing of paper surfaces, such as applying a coating agent only to necessary areas to save on coating agents, is increasing in proportion to the times in many fields.

Conventionally, as a partial polishing treatment device, a combination of a gravure coater device and a polishing device such as an endless press device is used.

(Problems to be Solved by the Invention) However, the gravure coater device has drawbacks such as requiring a long time from preparation work such as attaching and removing the plate to startup, and that the mechanical equipment and plate making costs are expensive. Because
When a gravure coater device and an endless press device capable of high-speed processing were combined, the excellent processing ability of the endless press device could not be fully utilized.

Furthermore, when a screen coater device is used instead of a gravure coater device, a large amount of coating is required with conventional screen coating agents, and it is difficult to apply a small amount. In addition, when coating a small amount, the coating agent is diluted with a solvent such as water, but this has the disadvantage of causing the coating agent to leak from the screen openings.In addition, conventional screen coater equipment has a slow coating speed, while the processing speed is fast. It is not possible to achieve consistency with the endless press equipment.

For example, in order to match the processing speed of an endless press device, a coating speed of about 70 to 100 revolutions per minute is required, but a conventional screen coater equipment has a coating speed of only about 60 revolutions per minute. Even when the screen coating method described above is combined with an endless press device, the advantage of the endless press device, which has a high processing speed, cannot be fully utilized.

(Means for Solving the Problems) In order to solve the above problems, the inventor of the present invention has conducted extensive research and has developed a paper feeder and a screen coater that automatically feed sheets of paper to be polished. The screen coater device is equipped with a series of devices, drying device, and polishing device, and the screen coater device is supplied with a screen polishing paint made of resin based on water-based or medium-to-high boiling point organic solvents, and the sheets fed from the paper feeder are This paper proposes a paper polishing method in which the paper is coated, dried, and then supplied to a polishing device.

Here, examples of the resin used in the glossy coating for screens include polyvinyl chloride (PVC), polyvinyl acetate, acrylic resin, urethane resin, and the like.

These resins can be added to medium-to-high boiling point organic solvents, made water-soluble and added to aqueous bases, or emulsified into aqueous bases using various surfactants to improve release from polishing equipment. The gloss paint for screens is adjusted by adding a thickener to the gloss paint for screens to adjust the viscosity.

Of these, gloss paints for screens that use medium-to-high boiling point organic solvents have problems such as odor, toxicity when used for food packaging, and high cost of materials, but water-based paints do not have these problems. There is no problem.

(Function) As described above, by composing the gloss paint for the screen with a water-based resin or a resin based on a medium-high boiling point organic solvent, it is possible to maintain a viscosity with appropriate thixotropy, which prevents clogging of the screen. The coating speed of the screen coater device can be increased. For example, the coating speed can be increased to 80 rpm.

Therefore, in the present invention, it is possible to achieve compatibility with an endless press machine that has a high processing speed, and it is possible to perform partial polishing of the paper surface quickly and smoothly in a series of steps.

In addition, this invention uses a screen coater device that allows easy installation and removal of the screen plate, thereby shortening the time required to prepare for polishing treatment and making it easy to rework the coated area, making it possible to produce a wide variety of products in small quantities. It becomes possible.

Furthermore, there are other effects such as lower mechanical equipment and plate making costs compared to gravure coater equipment.

(Example) The present invention will be described below based on illustrated embodiments.

Reference numeral 1 denotes a paper feeding device that automatically supplies sheets 3 placed on a paper tray 2 whose surfaces are to be polished, and the sheets 3 fed from the paper feeding device 1 are transferred to a powder removing device 4. will be sent to The powder removing device 4 has a pair of pressing rolls 5, 5, and when the sheet 3 is passed between the pressing rolls 5, 5, powder adhering to the front and back surfaces of the sheet 3 is removed. The powder removing device 4 evacuates the inside of the machine and has its exhaust port connected to a dust collector (not shown), and the removed powder is collected in this dust collector.

The sheet 3 sent out by the powder removal device 4 is sent to a corona discharge treatment device 7 through a belt conveyor 6,
The corona discharge treatment apparatus 7 is provided with an endless belt 10 suspended by suspension rolls 8.8, tension rolls 9, etc., and an electrode roll 11 is provided at the center of the back surface of the endless belt 10. A corona discharge electrode 12 is provided on the surface of the endless belt 10 so as to face the corona discharge electrode 12 .

The sheets 3 supplied to the corona discharge treatment device 7 through the belt conveyor 6 are placed on the endless belt 1o and passed between the electrode roll 11 and the corona discharge electrode 12, and in this process, the sheets 3 are discharge treated by the corona discharge electrode 12. be done.

This activates the inactive state of the surface of the dryer or wax in the printing ink, increasing the temperature and adhesion of the surface and making it easier to perform ejection processing.

The sheet 3 that has undergone the corona discharge treatment is fed to a screen coater device 13 .

The screen coater device I3 is composed of an impression roll 13a and a screen plate 13b provided on the impression roll 13a, and a screen gloss coating made of emulsified resin is supplied onto the screen plate 13b. ,
When the sheet 3 is fed onto the impression roll 13a, the screen plate 13b moves in the application direction while scraping out the glossy paint with the squeegee 13c, and the glossy paint is applied onto the sheet 3.

In addition, after the application of the support paint is completed, the screen plate 13b and the squeegee 13c return to their original positions and apply the next sheet 3.
Prepare for application of gloss paint.

After the gloss coating has been applied in this manner, the sheets 3 are fed through a conveyor belt 14 into a hot-air infrared drying device 15 . The hot air drying device 15 has suspended rolls 16.1.
6 and tension rolls 17 . . . , an endless belt 18 is provided.
Far infrared heaters 19... and Erohin heaters are arranged above, and furthermore, pressure devices 20 and 20 are provided at the top of the machine frame.

The sheet 3 placed on the conveyor belt 14 is transferred to the endless belt 18 and passed under the infrared heaters 19-..., where it is passed under the far-infrared heater 19 and the pressure 20.
．． Warm air is blown onto the surface of the branch paper 3 by the air supplied from 20, and the branch paper 3 coated with the glossy paint is stably dried.

After passing under the far infrared heater 19..., the sheet 3
The water travels on an endless belt 18, and is then supplied to a pressurized humidifier 22 equipped with a water tank 21 below, if necessary. The pressurized humidifier 22 includes a water absorption roll 22b made of sponge or cloth, etc., which is in contact with the pressure bonding roll 22a, and a fanching roll 22c, which is in contact with the water absorption roll 22b and a part of which is immersed in the water tank 21. , the sheet 3 placed on the endless belt 18 is placed on the pressure roll 22
a and the water supply roll 22b.

In the pressurized humidification device 22, appropriate moisture is absorbed from the fanching roll 22c immersed in the water tank 21 to the water absorption roll 22.
b, water supply roll 22b and pressure roll 22
Since the sheet 3 passes between the spaces a, the sheet 3 receives appropriate humidification and pressure, giving the paper flexibility. Next, the sheet 3 is passed through a belt conveyor 23 connected to rolls 22a and 22b to an endless press device 2, which is a polishing device.
4.

The endless press device 24 is provided with an endless steel belt 27 made of stainless steel, which is suspended between a heating roll 25 and a roll 26. , for example, to 120 to 140° C., and the heat is transferred to the endless steel belt 27.

Further, a pressure roll 28 whose axis is pressed in the axial direction of the heating roll 25 by a hydraulic mechanism is provided, so that the sheet 3 fed to the endless press device 24 is pressed between the endless steel belt 27 and the pressure roll 28. While passing through, the paper is heated and pressurized, and the mirror surface of the endless steel belt 27 polishes the surface of the branch paper coated with the gloss paint. Note that the endless press device 24 is provided with cold water nozzles 29 . state.

Therefore, below the endless steel belt 27, there is provided a conveyor belt 30 which receives the sheets 3 peeled off by hand and guides them to the outside of the endless press device 24. The collected sheets 3 are sent to an automatic paper pick-up device 31.

(Effects of the Invention) As described above, the present invention allows sheet paper to pass through a screen coater device, a dryer, and a polishing device in order, thereby
The present invention uses a screen coater device to apply a polishing treatment to appropriate locations on a sheet of paper, making it easier to attach and remove the plate and shorten the time required to prepare for the polishing treatment. In addition, it is easy to modify the coating section, surface treatment of a wide variety of products and small quantities is possible, and at the same time, mechanical equipment and plate making costs are lower than that of a gravure coater.

Furthermore, in this invention, the coating speed of the screen coater device can be increased by using a screen polishing paint composed of a water-based or medium-high boiling point organic solvent-based resin, so an endless press device is used as the polishing device. When used with endless press equipment, without reducing production,
Therefore, partial polishing of the paper surface can be performed in a series of steps at high speed and smoothly.

In addition, in the above-mentioned embodiments, the surface inert state of the dryer or wax in the printing ink that is observed during high-speed printing is activated, and the surface is made to be in a state that is easy to polish by increasing the moisture and adhesion of the surface. For this purpose, a powder removal device 4 and a corona discharge treatment device 7 are provided, but in the case of sheets that are already in a state where they can be easily polished, it is not necessary to provide these devices.

Further, in the above-described embodiment, since a pressurized humidifying device and an endless press device are provided, it is possible to prevent poor press bonding of sheets, which causes matting or cracking over time.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention; FIG. 1 is a plan view, FIG. 2 is a side view, and FIG. 3 is an enlarged side view of the main parts. In the figure, 1 is a paper feeding device, 13 is a screen coater device,
15 is a hot air infrared dryer, and 24 is an endless press device.

Claims (1)

[Claims] A series of paper feeding devices, screen coater devices, drying devices, and polishing devices are installed to automatically supply sheets of paper to be polished. 1. A method for polishing a paper surface, comprising: supplying a glossing paint for a screen, applying it onto a sheet of paper sent from a paper feeding device, drying it, and then supplying it to a polishing device.