RUBBER ROLLERS FOR PRINTING MACHINES
The rubber compounds on rollers are specialized for specific conditions such as the speed at which they will be running (higher speeds generate more heat) and the types of chemicals they will be exposed to.
Talking of a rubber roller, the most important thing is to know the printing machine in and out; how the roller works and it application fields.
Why Printing Rollers are critical to QUALITY ?
Printing quality depends on:
- the quality of paper
- the quality of ink
- the quality of rubber rollers
Points of contemplation in a printing machine:
- Year of manufacture: In some cases, there are differences in the same model of printing machine, depending on the year of production. This happens for instance in Heidelberg and Roland, where the same model may have different scheme of rollers from one year to another.
- Number of printing units:The printing machine may be composed of one or more printing units. Accordingly it may be a machine with one, two or more colors. The group of rollers of one printing unit is called a set of rollers. In a set of rollers there are two groups of rollers, the inking rollers and the dampening rollers,
- Inking rollers: The inking rollers are normally composed of the ink ductor roller (rubber rollers that first receive the ink), the ink form rollers (rollers that give the ink to the printing plate) and the distributor rollers. There are also oscillating rollers which are normally recovered with rilsan or ebonite.
- Dampening rollers:In the dampening unit there are also rollers that receive the water and rollers that give the water to the printing plate. Accordingly, there may be two different dampening systems:
- Conventional system
- Alcolor system
- Type of ink used (Conventional or UV): Another important consideration is the kind of ink machine is printing with. Rubber applied in recovering/ making of the rollers is different for UV and Conventional inks. Proper rubber compound must be applied in the rollers otherwise the rubber will be destroyed in a very short time.
- Upper unit & Lower unit: The machine models may have Upper and Lower printing units. This is important because their rubber rollers schemes are normally different. For instance, Roland machine has Upper & Lower units of rollers.
- Any other type of roller: The printing machine may have other type of rollers like Oscillating roller/ Numbering roller/ Bare back roller, etc. This must be taken care of.
This way, when we are asked for a set of rollers we must know:
- What is the year of manufacture/ model number of machine?
- Is it a complete set of rollers or only the inking rollers or dampening rollers?
- Which is the dampening system?
- Which is the type of ink used (Conventional or UV)?
- Which is the printing unit of the machine, (upper or lower printing unit)?
- Is there any other type of roller groups like the numbering rollers or the coating printing units?