Practical Tips | The Secrets of Rubber Roller Storage and Maintenance on Printing Presses (Part 1)

How should rubber rollers be properly stored and maintained? What should be noted when they are first put into use? How can daily storage and maintenance deliver both good print quality and a longer service life for rubber rollers?

Printing Jun's senior experts have summarized and organized their extensive experience in the storage and maintenance of printing press rubber rollers, and are now sharing it with you. As the content is substantial, it is divided into two parts; Part 1 is presented here.

1. Points to Note During Storage

For rubber rollers that have never been used, or used rubber rollers that have been taken out of service, store them in optimal condition according to the following conditions.

▌ Storage Location

① Keep the room temperature at 15-25℃ (59-77℉) and the humidity below 60%.

② Store in a dark place not exposed to direct sunlight. (Ultraviolet rays in sunlight will age the surface of rubber rollers.)

③ Do not store in a room containing UV equipment (which emits ozone), corona discharge treatment equipment, static eliminators or high-voltage power supply equipment. (These devices will cause rubber rollers to crack and become unusable.)

④ Place in a location indoors with little air circulation.

▌ Storage Method

⑤ During storage, the roller shaft of the rubber roller must be placed on a cradle, and the rubber surface must not come into contact with other objects. When standing the rubber roller upright, be careful not to let it touch hard objects. In particular, never place rubber rollers directly on the floor for storage; otherwise, the rubber surface will develop depressions and will no longer be able to take up ink.

⑥ Do not remove the wrapping paper during storage. If the wrapping paper is damaged, repair it and take care to avoid air leakage. (The rubber roller inside will age due to air erosion and become difficult to pick up ink.)

⑦ Do not place heating appliances or heat-generating objects near the rubber roller storage area. (Rubber will undergo chemical changes under the influence of high heat.)

1. Points to Note When Starting Use

① When carrying a rubber roller, be sure to hold the bearing sections at both ends, and take care not to damage the two ends of the rubber roller or the parts where it rests on the support.

② Before mounting it on the machine, place it on a cradle; even for a moment, never place the rubber roller directly on the floor.

③ New rubber rollers have an anti-aging agent applied to their surface; before use, gently wipe the surface clean with a cleaning agent.

④ After a new rubber roller is mounted on the machine, it must be fully supplied with ink. Run it only after the surface of the rubber roller is fully coated with ink, ensuring that the ink acts as a lubricant. (Running without inking the surface of the rubber roller will wear the surface, and in a short time the surface will become fuzzy and unusable.)

⑤ Water rollers require the same treatment. Use a watering can or similar utensil to apply sufficient water to the water roller before running. At this time, separate the two rollers, wet one of them with water, and then run.

⑥ At the beginning, do not apply excessive pressure to the rubber roller; set an appropriate nip width. The nip width between ink rollers affects the fluidity of the ink, so controlling the nip width is very important.

⑦ Depending on the image and text requirements, the ink fountain sometimes needs to be completely closed. If the ink fountain completely stops supplying ink, some parts of the rubber roller will idle in an ink-starved state; if the rubber roller idles without ink, it is as if there were no lubricant, and the rubber roller will become rough due to heat expansion, so a minimum amount of ink must be supplied.

⑧ UV-dedicated rubber rollers will swell under the influence of machine oil, grease, oil-based inks and cleaning agents. Therefore, in addition to paying attention during daily use, attention should also begin from the machine assembly and rubber roller adjustment stages. If it is a UV-compatible rubber roller, it can be handled in the same way as ordinary ink rollers.

⑨ When using a new UV-compatible rubber roller, poor ink drying will occur at the beginning. At the completion of assembly, the rubber roller first needs to be acclimated to UV ink; pour UV ink thinner onto the rubber roller and then let it idle.

⑩ When the machine is stopped, pour new UV ink or UV ink thinner onto the rubber. When starting formal operation, use oil-based ink for 2-3 days first, and then use UV ink.