Patent Application
20200338881
The present invention relates to a ductor roller for printing machines and, in particular, to protection members of electromagnetic valves installed in the ductor roller.
Offset printing machines and letterpress machines are provided with a ductor roller between an ink fountain roller and an ink distribution roller; the ductor roller is switched between a state in contact with the ink fountain roller and the other state in contact with the ink distribution roller. The ductor roller receives ink when in contact with the ink fountain roller and delivers the ink when in contact with the ink distribution roller. The contact period of the ductor roller with the ink fountain roller is controlled so that the ink supply amount to the plate cylinder is controlled.
When the ductor roller comprises plural individual ductor rollers and when the individual ductor rollers are controlled so as to independently move forward and backward, the ink supply amount is made finely adjustable in the axial direction of the ink fountain roller (Patent Document 1: JP 3008026B) . The individual ductor rollers are associated with a fixed shaft and advance toward the ink fountain roller by pistons that pneumatically advance from the shaft. Further, the individual ductor rollers are biased toward the ink distribution roller by springs and contact pieces and return toward the ink distribution roller when the air supply is shut down. In addition, electromagnetic valves are installed to the fixed shaft for controlling the individual ductor rollers.
When the electromagnetic valves are contaminated by cleaning liquid for printing machines, ink, or other materials, the correct operation of the electromagnetic valves may be impeded. Therefore, Patent Document 1 discloses to provide oil-resistant rubber products for covering clearance between the individual ductor rollers to prevent the cleaning liquid and so on from entering into the clearance. In other words, the rubber products cover the side ends of the individual ductor rollers so as to shut out the cleaning liquid and so on.
Patent Document 1: JP 3008026B
The inventors have found that the oil-resistant rubber products deteriorate by the cleaning liquid for a short period and have to be exchanged frequently.
The object of the invention is to improve the durability of protection members for electromagnetic valves in ductor rollers for printing machines.
A ductor roller for a printing machine according to the invention comprises: a shaft provided with an air supply pipe; a plurality of individual ductor rollers; and a plurality of electromagnetic valves. The individual ductor rollers and the electromagnetic valves are connected to the shaft, and the individual ductor rollers are advanced pneumatically by said electromagnetic valves.
In the ductor roller for a printing machine according to the invention,
the individual ductor rollers are provided with housings associated with the shaft and configured to move forward and backward; roller members configured to contact an ink fountain roller and an ink distribution roller, both of the printing machine; and bearing members connecting the roller members to the housings,
said electromagnetic valves are placed in said housings, and
protection members for the electromagnetic valves are placed in clearance between the individual ductor rollers, and are oil-resistant, are associated with and supported by the shaft, and are provided with circularly cylindrical or arc-like covers covering at least upper portions of side ends of said housings. Preferably, the protection members comprise: plate-like portions having association holes that are associated with said shaft; and said circularly cylindrical or arc-like covers.
According to the invention, the covers of protection members cover at least the upper side end portions of the housings and block the cleaning liquid and so on. The covers are circularly cylindrical or arc-like, guide downward the cleaning liquid received by the covers, and prevent the cleaning liquid from reaching the electromagnetic valves. The protection members have a constant shape, do not deform such as rubbers do, and have basically no need for exchange due to their oil-resistance.
Preferably, the covers are circularly cylindrical and have a trough on a circular face of the circularly cylindrical covers, and the trough is low at a central portion of the circularly cylindrical covers and high at side end portions of the circularly cylindrical covers, both in an axial direction of said shaft. The cleaning liquid adhering to the covers flows along the troughs and does not intrude to the electromagnetic valves. Further, the cleaning liquid is discharged to the outside through the clearance between the individual ductor rollers.
Further preferably, a guide for guiding the cleaning liquid for printing machines downward is present at a central portion of the trough in the axial direction. The guide may be a projection or a groove, and the cleaning liquid flows along the guide downward.
Most preferably, at least a projection dropping the cleaning liquid downward is present at a lower end of the trough. The cleaning liquid reached the lower end of the trough concentrates at and drops from the projection and is discharged through the clearance between the individual ductor rollers.
There is such a ductor roller for printing machines that has a shaft provided with an air supply pipe, plural electromagnetic valves, and plural individual ductor rollers, both connected to the shaft. The individual ductor rollers have housings, bearings, and roller members, and the roller members are connected to the housings via the bearings. The individual ductor rollers are advanced toward the ink fountain roller pneumatically by said electromagnetic valves, and the electromagnetic valves are placed in the housings. The protection members according to the invention are suitable for such ductor rollers for printing machines. The protection members are oil-resistant and have association holes for association with the shaft and circularly cylindrical covers that cover at least the upper portions of side ends of the housings of the individual ductor rollers. Further, the circular face of the circularly cylindrical covers is provided with a trough that is lower at the center portion and higher at both end portions in the axial direction of the circularly cylindrical covers. The covers cover at least a side end of the housing and receive cleaning liquid intruding through the clearance between the individual ductor rollers. The cleaning liquid flows downward along the trough and is discharged through the clearance between the individual ductor rollers.
The best embodiment for carrying out the invention will be described.
As shown in
The individual ductor rollers 12 advance pneumatically toward the ink fountain roller 4 and retract by the springs 23 and the contact pieces 22 toward the ink distribution roller 6. The directions in the specification are shown in
The structure of the protection member 14 is shown in
On the circular surface of the cylindrical portion 32, there is present a ring-like guide 25 at the central portion in the axial direction, and, at both sides of the ring, there is present a trough 24 that is higher toward the edge portions and lower toward the central portion in the axial direction. The trough 24 prevents mist of the cleaning liquid and so on from scattering when the mist and so on collide. The cleaning liquid adhering on the trough 24 is downward guided by the guide 25 along the trough 24. There is a projection 28 at the lower end of the guide 25, and the cleaning liquid drops from the projection 28 and is discharged into the clearance between the roller members 16, 16.
The functions of the embodiment will be described. The protection members 14 are oil-resistant and have no need for exchange. The inner diameter of the cylindrical portion 32 is a bit larger than the outer diameter of the housing 13 and allows the forward and backward movement of the individual ductor rollers 12. When cleaning the printing machine, the cleaning liquid (the main component is an organic solvent or a machine oil.) is sprayed onto the ductor roller 2, collides the trough 24 through the clearance between the roller members 16, 16, is prevented from scattering toward the housing 13, and is released along the trough 24. At the lower end of the guide 25, the cleaning liquid drops from the projection 28 and falls through the clearance between the roller members 16, 16. Thus, the intrusion of the cleaning liquid to the electromagnetic valves 10 is prevented. While ink mist and other contaminants adhere also on the trough 24, they are released with the cleaning liquid and so on to the outside.
According to the embodiment, the individual ductor rollers 12 are retracted by the spring 23 and the contact piece 22, but they may be retracted by the pistons 21 retracting pneumatically.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2017-239316 | Dec 2017 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2018/042649 | 11/19/2018 | WO | 00 |
