Replacing the ink roller is not a difficult task but can cause some unexpected problems.
Once the ink roller is removed from the press, the shaft has to be removed from the ink roller. Most press operators normally refer to that shaft as the “dead shaft”.
The dead shaft is removed by first removing the eccentric bearing collars on each end of the ink roller. Driving it counter-clockwise, as viewed from the end of the roller shaft, normally loosens the collar. (It is customary to lock the eccentric collars by driving them in a clock wise direction, looking at the collar from the end of the shaft; however, the collar can be locked in a counter-clockwise direction, which will make it impossible to remove by trying to loosen the collar in that direction. If that’s the case, try to remove it by turning it in the clockwise direction.)
Once the eccentric collars have been removed, the dead shaft can be removed by impacting the end of the shaft with a dead blow hammer. That blow will cause the shaft to slide out of the roller bearings, which are still in the ink roller.
A second method would be to place a lead, brass or copper block next to the dead shaft and then impact the softer metal block to remove the shaft. The third method of removing the dead shaft is to place a block of brass, lead or copper on the floor, then stand the ink roller on end, raise the roller up and let it drop so that the dead shaft impacts against the metal block that was placed on the floor. This will normally cause the shaft to slide out of the bearings that are still in the ends of the ink roller. Once the dead shaft is through the first bearing it can be normally removed by pulling it through the second bearing by hand. A puller can be attached to the shaft and the first roller bearing for dead shafts that are hard to remove. Any of these methods will work, but remember, the purpose is to remove the dead shaft without damaging it.
When installing a new ink roller, take the time to replace the bearings as well. Installing new bearings will prevent older bearings from seizing up and having to replace the bearings during a press run, an expensive proposition.
The new ink roller can now be prepared to accept the dead shaft
The dead shaft should be thoroughly cleaned and the surface checked for any areas that might restrict the installation of the shaft into the roller bearings. Any high spots, such as dimples made by steel hammers or other hard objects that would inhibit the installation of the shaft, must be filed or ground down.
New roller bearings can now be mounted into the new ink roller. First, place the roller bearing over the end of the ink roller with the eccentric lock facing to the outside. Now drive the bearing into the ink roller core. Be careful to contact only the outside ring of the bearing surface when driving the bearing into place to prevent damage to the new bearing as it’s driven into the ink roller’s core.
The dead shaft can now be installed.
Stand on end
Typically, the easiest way to install single-width ink rollers is to stand the ink roller on end on the floor and then insert the shaft.
Double-width rollers are generally installed by first installing as much of the shaft as possible on a horizontal surface then tilting the ink roller vertical so that the shaft can slide into the second roller bearing. The new ink roller can then be placed horizontally on a table so that the end of the shaft can be positioned equally, which will center the ink roller on the dead shaft.
Next, install to two bearing eccentric collars. Place the eccentric collar over the eccentric shoulder of the bearing. Using a punch and hammer rotate the eccentric collar in a clockwise rotation as viewed from the end of the roller shaft. This will lock the bearing to the shaft, which will prevent the ink roller from oscillating from side to side while the press is running.
Lastly, tighten the hex set screws on the eccentric collars.
Properly installing ink rollers will prevent shorter than normal ink roller life and will improve ink transfer. Properly installing the dead shafts will save time, aggravation and extend the life of the shaft.
Frank Bourlon has more than 30 years experience in the newspaper industry. He is the Associate Director for Newspaper Production & Research Center. He can be reached @ 405-524-7774.