TRC
 
 

ROLLER CARE

 
 
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TRC Roller Re conditioning Procedure
In order to acquaint offset lithographers and other users of rubber or urethane printing rollers with our procedure, the details are given below.
 
  1. Rollers received for reconditioning are carefully inspected, as they are booked:
    (a.) The covering is checked for size, cuts, rule marks, cracking and other mechanical damage and adhesions to the core.
    (b.) The core is checked for damage or excessive wear on journals. Bearings, if furnished are checked for trueness and free running.
  2. If the cover inspection indicates that the roller cannot be reground to within required tolerances, the customer is immediately advised that the roller should be recovered.
  3. Metal defects are normally repaired and undersize journals metalized. This will not be done if repairs are expressively extensive as compared with the value of the roller and the core. In this case, the customer is advised so as to decide which is most economical.
  4. The roller is reground, removing the absolute minimum consistent with adequate cleanup. While still on the grinder, it is inspected for diameter, taper, run out and surface finish.
  5. It is then polished at high speed with fine sandpaper, until the surface is brought to the desired smoothness. Whilst still on the polisher, the shoulders are sanded to remove excess dried ink. The core and the journals are also cleaned.
  6. The surface of the roller is then carefully washed with solvent to remove polishing dust and inspected again for size and surface defects.
  7. Exposed metal parts are painted and the journals protected with rust inhibitor.
  8. The roller is wrapped in special protective paper for shipment to customer.

Glazing is due to an accumulation of a dried ink film and if not corrected, the roller surface loses its affinity for ink. A glazed roller loses its frictional potential and slows down due to poor traction. When it strikes the plate, the cylinder speed which is greater than that of slower glazed roller, a skid is produced. This, in turn causes a streak across the plate. This condition comes about gradually and eventually induces faint areas on the printed sheets.

If rollers are not factory re conditioned at regular intervals, the ink that remains on the surface will cause the rollers to crack. This would affect the quality of printing. Even under optimum operating conditions, using extreme care and the best materials in wash-ups, the roller ends frequently do not get washed. This leads to cracking at shoulders. If the shoulders crack, the crack will go further into the roller, leading to progressive and complete destruction.

When the roller surface is badly glazed, factory reconditioning is the only way to restore it to the proper durometer and remove the glazed surface. In the most practical terms, regular reconditioning of rollers is a form of 'printing insurance'. Care of rollers is the most effective means of maintaining the quality of the printing. Our highly qualified Sales Engineer could check your rollers for reconditioning every time he visits you. Many rollers can be reconditioned locally at the plants itself, thereby saving time and trouble.
 
 
 
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