Printing – Printing members – Rolling contact
Patent
1987-08-19
1989-03-14
Tufariello, T. M.
Printing
Printing members
Rolling contact
204 25, B41F 1310, C25D 704
Patent
active
048122190
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to a method of producing a surface sleeve for a plate cylinder, said method comprising arranging around a supporting mandrel a basic sleeve which is made of an electrically conductive material such as metal, preferably nickel, and has an inner surface which is complementary to the outer surface of the mandrel, electrolytically depositing an inner metal layer on the outer surface of the basic sleeve, and providing on the said inner layer an outer copper layer with a smooth circularly cylindrical surface.
The term "cyanide copper" as used in the present specification and claims means copper which has been deposited in a cyanide-containing bath, the term "high-gloss copper" means copper which has been deposited in a bath containing gloss promoting or gloss generating additives, and the term "chloride nickel" means nickel which has been deposited in an acidic nickel chloride bath.
Published European patent application No. 92285 describes a method of the above type in which a nickel layer is deposited on a mandrel having a slightly conical outer surface. The basic sleeve thus formed is loosened and removed from the said first mandrel and slipped over another conical mandrel which is provided with an axial bore for compressed air with air outlets on the peripheral surface of the mandrel. During the process of slipping the formed basic sleeve of nickel over the said second mandrel, the thin-walled sleeve is exposed to a certain tangential stretching produced by means of the compressed air. While the basic sleeve is arranged on the mandrel in a stretched condition, its outer surface is immersed in a cyanide containing bath, and a thin layer of cyanide copper is deposited electrolytically on the outer conical surface of the basic sleeve. The mandrel with the sleeve arranged thereon is then transferred to another bath in which high-gloss copper in a layer, which is substantially thicker than the cyanide copper layer, is deposited on top of the cyanide copper layer. As the outer peripheral surface of the basic sleeve with the two coats of copper layers is substantially conical, and as the thickness of the electrolytically deposited copper layers is inevitable slightly larger at the ends of the sleeve than along the intermediate part, the mandrel with the sleeve is now arranged in a lathe, and the last deposited copper layer is turned so that a completely circularly cylindrical surface is achieved. Finally, yet a copper layer of so-called hard copper is deposited electrolytically and polished, whereupon the desired gravure pattern is produced photographically or by engraving in a manner known per se on the said polished outer surface of the outermost copper layer.
In this known method the intermediate one of the deposited copper layers has to be sufficiently thick to compensate for the conical shape of the surface at the said turning. As the thickness of the copper layer thus has to exceed the difference between the largest and the smallest diameter of the conical shape, sleeves of a certain length may involve a relatively large thickness of the said intermediate copper layer. The result is that the depositing of the said intermediate metal layer, which is high-gloss copper in the known method, takes diproportionately long, and also the necessary turning operation contributes to increasing the time of production and thus the cost of production for the surface sleeve.
The present invention provides a method of the above type, in which it is possible to produce surface sleeves for plate cylinders in a manner which takes substantially less time and is thus cheaper than the above known method.
The method according to the invention is characterized in using a mandrel and a basic sleeve having outer peripheral surfaces which have a circularly cylindrical shape, and cutting off the end parts of the sleeve after the electrolytic depositing of the outer copper layer thereon. It has been found that by starting from a basic sleeve, the peripheral outer surface of which has a circularly cylindrical s
REFERENCES:
patent: 4276148 (1981-06-01), Otthofer, Jr.
patent: 4503769 (1985-03-01), Andersen
Brondsted Ole
Sattrup Jens E.
Sattrup Jens Erik
Tufariello T. M.
LandOfFree
Method of producing a surface sleeve for a plate cylinder for pr does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method of producing a surface sleeve for a plate cylinder for pr, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method of producing a surface sleeve for a plate cylinder for pr will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-892151