Rubber roller application new perspective
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In the selection of rubber rollers and their cleaning agents, we should pay attention to comprehensive benefits, reduce integration and cost, improve printing quality, and enhance corporate competitiveness.
Installation
Install the new rubber roller bearing correctly. Firstly, clean the impurities at both ends of the new rubber roller, and then select the bearings whose specifications and models meet the design requirements, apply the lubricating oil on each mating surface, and beat the special bearing sleeve correctly and evenly until the bearing is installed in place. Do not directly apply force to the bearing, and feel free to knock to prevent the bearing from being damaged before it is used.
Ensure the lubrication of each bearing and shaft seat of the rubber roller. Before the rubber roller is installed, the outer surface of the rubber roller and the rubber roller bearing sleeve and bracket on the machine should be coated with lubricating grease to minimize the rotation, impact and friction formed by the back and forth of the ink roller. Reduce wear on both sides of the rubber sleeve and the shaft seat.
In recent years, U V printing has been widely used, and U V and ordinary dual-purpose ink rollers have appeared. The installation of U V and ordinary dual-purpose ink rollers is as follows.
1. New ink roller adaptation program
Before installing a new set of new rubber rollers and preparing to print with UV ink, the ink roller must be run for 2 to 3 hours with UV transparent ink or UV ink, so that the ink roller is completely adapted to the UV ink, and then washed with UV washing machine water. The UV printing process is available. If you do not follow the above procedure, some UV inks may become hard and accumulate on the surface of the ink roller, resulting in uneven ink, heat and difficult to clean, and the ink roller is also prone to wear. If ordinary ink is used for printing with ordinary ink, it can be printed after loading.
2.UV ink printing and ordinary ink printing conversion program
When converting U V ink to ordinary ink, the ink roller should be cleaned with special U V washing machine water, and then printed with ordinary ink. Before printing, check whether all the ink rollers are completely inked. When converting from ordinary ink to U V ink, U V printing can be performed after cleaning the ink roller. However, if it is found that the ink is not good, the ink roller can be operated with U V transparent ink or U V ink for about 12 hours before UV printing.
Debugging
To accurately determine the proper position of the rubber roller on the printing press, regulate the water roller and ink roller pressure. Whether the position of the rubber roller is appropriate or not is directly related to the uniformity of ink transfer and ink brushing, directly affecting the quality of the printed matter, and directly affects other aspects, such as the life of the rubber roller. The contact pressure between the ink rollers should be kept uniform and moderate. If the pressure is too large, the rubber roller will be deformed under pressure. The colloid will expand due to the heat of distribution. The ink will be easily thinned even if it is heated, and even “degumming” will affect the quality of the printing ink. On the other hand, it is easy to damage the rubber roller shaft (bearing) or the shaft hole. It is also important to adjust the height of the inking roller. If it is too high, the ink will be unevenly distributed. If it is too low, it will easily scratch the gel and increase the wear of the printing plate. The contact between the inking roller and the printing plate can generally be placed on the printing plate with a tough paper strip of about 40g / m2. When the inking roller is rolled up, the paper strip can be pulled with a sense of pressure resistance.
The height of the rubber roller adjustment is also related to the structure of the print. If the printed matter with the background color is printed, the rubber roller can be adjusted to a lower degree with an error of ±0.5 mm, so that the ink delivered to the printing rubber roller by the ink roller is relatively uniform, and the printed product is pleasing to the eye, otherwise, the ink is easy to appear. Bars, ink roads, etc. When printing text, the height of the rubber roller is basically flat or slightly lower than the text version, so that the printing rubber roller can gently rub the printing plate, so that the text is printed clearly and cleanly, and the rubber roller wear surface is small. Not easy to damage, can extend the life of the plate. When adjusting, you should use the rubberizing roller. First remove the printing plate and let the adjusting roller horizontally extend and pull out several times. The size of the ink dot on the rubberizing roller will be displayed immediately. The operator can determine the printing adhesive according to the different needs of printing. The height of the roller is then locked to the top wire so that the height of the rubber roller does not change during high-speed printing.
Be patient when debugging the rubber roller, so as to avoid the following situation: the surface of the rubber roller is damaged, the slag is removed, the graphic is ambiguous, the text is missing, the paste is broken, and even the paste is glued; the graphics are different, even the printed surface is only The graphic prints have no ink color; the adjustment is too tight and the printing rubber roller is broken, causing equipment accidents.
Use
1. Requirements for the environment of the rubber roller
Printing production in a humid, humid, dusty environment, coupled with high-speed operation of the machine, will increase the surface temperature of the rubber roller, expand the colloid, increase the friction of the rubber roller, affect the quality of the product, and shorten the service life of the rubber roller.
Conditional printing companies, the offset printing workshop should install air conditioning, and keep the workshop clean and clean.
2. Problems that should be paid attention to in printing production
(1) boot
It must be turned on with ink. If it is not used, it is necessary to add lubricant. The water roller should also be operated with water, and it must not be “dry-grinded”. Otherwise, the rubber roller will be quickly scrapped.
(2) Long downtime
The ink roller is pressed at a certain fixed position, so that there is a possibility of partial depression. At this time, it is best to remove the ink roller and clean it to the ink tray for use. Do not place it directly on the table to prevent partial deformation of the rubber roller.
(3) Rubber roller aging
The rubber roller is used for a long time and aging, coupled with the erosion of chemicals, causing the rubber to lose the "slag". Such a rubber roller is preferably updated in time to avoid seriously affecting the quality of the printed product.
(4) The production environment temperature is too low
At this time, the ink is not easy to be evenly mixed, and an auxiliary material may be appropriately added to the ink, and it is strictly prohibited to use an infrared heater to bake the ink roller.
(5) Sundries
During the printing operation, the offset printing machine should be kept clean and tidy. The tools such as the ink shovel and the printing supplies cannot be randomly placed, and the lumps of the impurities and ink cannot be caught in the ink roller to scratch and crush the ink roller.
3. Rubber roller failure and treatment
(1) Surface crystallization and calcification of rubber roller
The surface of the high-quality rubber roller should be fine and smooth, and the hand feels slightly viscous, which has good ink transfer performance. In production, the rubber roller is affected by factors such as dampening solution, ink and paper for a long time. In addition, it is impossible to thoroughly clean each time. The residual impurities are deposited on the surface of the rubber roller layer by layer. Over time, the surface of the rubber roller will be closed. The capillary pores form a smooth crystalline layer similar to calcium, which seriously affects the ink transfer and water transfer performance, and cannot stably control the ink color of the print. In this case, after washing with the car wash water, it can be washed again with some citric acid water to chemically react some calcium impurities on the surface of the rubber roller to form a soluble substance for cleaning.
(2) The surface of the rubber roller is easy to have scratches and numb eyes
Because the rubber roller is relatively soft, a slight hard object will be scratched during high-speed operation. In particular, the alcohol dampening solution relies on the plate water roller, and once scratches occur, it can no longer be used. In order to avoid such failures, the first is to check whether the plate is tightened or the clamp is clamped, causing the cracks and cracks in the printing plate to be scratched by the plate water roller and the ink roller; the second is to see if the ink roller maintenance is not timely. There are many impurities such as ink, ink residue and so on, which accelerates the friction, heat and aging of the rubber roller, and makes the surface of the rubber roller full of numbness. In this case, the rubber roller is generally more serious.
(3) Premature cracking and aging of rubber roller
There are many reasons, such as excessive dry oil in the ink, so that the ink is dry on the rubber roller; the cleaning agent used for cleaning the rubber roller is improperly selected, the cleaning time is too rushed, and the impurities on the rubber roller cannot be thoroughly cleaned; the ambient temperature of the workshop Higher, the dampening cooling system works poorly, the large amount of heat generated during the operation of the rubber roller can not be dissipated in time, the internal temperature of the rubber roller is high; the performance of the rubber roller bearing is not good, and it is rotated by the ink roller, resulting in jumping friction, extrusion, etc. .
(4) Deinking
In the offset printing operation, the ink is emulsified due to "large water and large ink", and a hydrophilic foundation is formed on the smooth rubber roller, and deinking occurs. The solution is to shovel the emulsified ink, wash the deinking roller with gasoline, mix the surface with a 5% aqueous solution of sodium hydroxide and talc, remove the hydrophilic layer, and restore the oleophilic properties of the ink roller. At the same time, the metal roller (or hard roller) is also treated accordingly. The hard roller can also be sanded with fine water sand in the state of water drenching, and it should not be fixed at the same part, otherwise the rubber roller will be damaged. The fundamental method is to control the p H value of the water hopper, do a good job of water and ink balance, and reduce the emulsification of the ink.
Maintenance
Whether the maintenance of the ink roller is reasonable and in place has a direct impact on the service life of the ink roller and the printing quality.
Regular maintenance
After each printing, the ink, paper powder and paper wool remaining on the rubber roller should be cleaned. Pay special attention to clean and wipe the residue at both ends of the rubber roller to avoid long-term accumulation of residue, so that the rubber roller is aging and cracked at both ends. . Among them, the cleaning agent must use the specified chemical reagents, and must not use corrosive solvents; the cloth is preferably knitted with a cloth to prevent cotton wool from remaining.
Check whether the bearings at both ends of the rubber roller are freely movable and in good condition. If loose or worn, tighten or replace them in time. When the bearing of the rubber roller is damaged to a certain extent, it will produce jumping friction and extrusion, shorten the service life of the rubber roller, and cause the printed product to have an "ink/water bar". The rubber roller should be taken down every week to butter the bearing and replace the bearing with severe wear and poor rotation to ensure the normal use of the rubber roller.
Check if the rubber on the surface of the rubber roller is good, especially the plate rubber roller must choose the best. For rubber sheets with cracks and more eyes on the surface, it should be re-polished and replaced in time.
2. Rotation maintenance of multi-color group
In the weekly maintenance, it is difficult to carry out thorough and thorough maintenance of the multi-color platform offset press or the rotary machine. Under the premise of normal day maintenance, according to the structural characteristics of the multiple color unit of the equipment, the monthly maintenance and the half-year maintenance are carried out. The project is broken down to weekly, with one print unit being focused on each week. This method is also adopted for the rubber roller maintenance of each color group. Every week, all the ink rollers of one color unit are inspected and maintained, and the rubber roller is mainly checked for calcification, whether the bearing is lack of oil, and whether the pressure between the rubber rollers is to be adjusted.
In this month, all the rubber rollers of the whole machine can be rotated at least once. The machine is running normally for about half a year, and then check the maintenance manual for any maintenance contents.
When the color group is rotated and maintained, the personnel should have a reasonable division of labor, cooperate with each other to be tacit, the movement should be standardized, and various tools and detergents should be selected appropriately. No sharp tools can be used to shovel the rollers, rubber rollers, or reducers or bananas. Water cleaning rubber rollers, etc.; also need to make detailed records, including the main parts of maintenance, maintenance methods, hidden dangers found, maintenance plans, etc. Under special circumstances, work that cannot be completed this week should be scheduled in the next week's maintenance schedule to ensure that the maintenance parts are implemented one by one.