Printing – Antismut device – Anti-offset material application
Patent
1996-06-21
1997-12-30
Burr, Edgar S.
Printing
Antismut device
Anti-offset material application
101423, B41F 3500
Patent
active
057018200
DESCRIPTION:
BRIEF SUMMARY
The invention starts with a device for washing and drying plates with characteristics described in the preamble of claim 1 This kind of device is used in a process involving several work stations for removing paint, keeping capillaries open and preserving or rubberizing and drying the surface of offset printing plates which are removed from the printing press after printing. The aim is to obtain a perfectly clean and preserved offset printing plate which can be archived and, in case of repeat orders, be reused in the printing press since it will remain in excellent condition.
The known device is provided with, sequentially, a washing station for removing the paint from the surface of the printing plate, a rinsing station for rinsing off the washing liquid and a station for preserving or rubberizing the printing surface of the printing plates, as well as a drying device consisting of rolls for squeezing out the liquid from the printing plate and/or of blow nozzles directed against the printing plate.
The printing plates are guided horizontally through the work station by pairs of rolls. The openings between the rolls, or roll gaps, are located on equal elevation and the printing plates are guided and conveyed by the clamping action of the pairs of rolls, whereby at least one roll per pair of rolls is a driving member.
The known device functions quite well with plane printing plates. When clamping the printing plates in a printing press, the edge of the printing plate is likely to bend, and the more the edge is bent, the more difficult it is to convey the printing plate between the pairs of rolls. There is greater wear on the rolls and liquid is spread from one station to the next, since the pairs of rolls are unable to sufficiently squeeze out the liquid from the printing plate as a consequence of the bent edge.
The object of the present invention is to create a washing and drying device which is also well suited for printing plates with a bent edge.
This object is solved by a device with characteristics given in claim 1. Advantageous further embodiments of the invention are the subject of the dependent claims.
The invention ensures an unobstructed passageway for the bent edge of a printing plate through all work stations of the device, either above or below the roll gap. Longitudinal guides marking the boundary of the passageway, are aligned with each other in a common line of sight in all work stations of the device. When a printing plate with bent edge is fed into the device in such a way that the bent edge is aligned parallel to the conveying direction, and that it is positioned in the passageway adjacent to the roll gap and can pass freely through the device, then the pairs of rolls grip only the plane area of the printing plates and are not hindered by the bent edge in doing this. The longitudinal guides for the bent edge marking the lateral boundaries of the unobstructed passageway through the device ensure that the plane area of the printing plates cannot drift from the roll gaps in transverse direction with respect to the conveying direction.
The guides are preferably located below the roll gap, so that the printing plate can be conveyed through the device with its printing side pointing upward and washed from the top. Since the bent edge points downward, there is no dead space on the top side where washing or rinsing liquid could accumulate, but the liquid can run off over the bent edge which also forms a dripping edge.
The guides are preferably formed by providing a circumferential groove in the cylindrical surface of the lower or upper roll of each pair of rolls into which the bent edge of the printing plate can project. Then, the boundaries of the groove represent at the same time the longitudinal guides. Should the bent edge come in contact with the boundary of the longitudinal guide, then it is virtually impossible that the plate is delayed at this boundary by friction in the longitudinal guide, but, a near friction free straight course is ensured, since the longitudinal guide is turning toge
REFERENCES:
patent: 176171 (1876-04-01), Dow
patent: 4083303 (1978-04-01), McInerny
patent: 4934266 (1990-06-01), Fantoni
patent: 5033376 (1991-07-01), Wiczak
patent: 5507226 (1996-04-01), Burke et al.
Burr Edgar S.
Nguyen Anthony H.
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