Browse Prior Art Database

Original Publication Date: 1990-Jun-30
Included in the Prior Art Database: 2004-Apr-05

Publishing Venue

Xerox Disclosure Journal


The coating of drums with photoconductive layers can be accomplished by different means, vacuum coating, roll coating, spraying, dipping, and the like. For dip coating embodiments in which a drum is dipped into a coating mixture, an undesirable coating is deposited on the inside of the drum. This undesirable coating can be prevented by the use of a unique drum holder which does not allow the coating mixture from penetrating the interior of the drums. As illustrated in the figure, this drum holder comprises O-ring 14 which is compressed near the upper interior of drum 10 between upper plug 16 having compression lip 18 and lower plug 12. Lower plug 12 fits loosely and extends, for example, about two-thirds the length of drum 10. Lower plug 12 may be solid to provide weight which assists in forcing drum 10 to submerge in the coating mixture. This drum holder design positions O-ring 14 at the upper interior of a drum 10 to facilitate rapid insertion and extraction of the drum holder. Compression lip 18 of upper plug 16 in cooperation with lower plug 12 compresses O-ring 14 to form an air tight seal between drum 10, compression lip 18 and lower plug 12. Air trapped within the interior of the drum 10 below O-ring 14 forms a protective blanket which prevents the coating mixture from entering the inside of drum 10. Compression of O-ring 14 between lower plug 12 and compression lip 18 can be accomplished by rotation of locking ring 22 around threaded rod 20 having one end screwed into a threaded hole in lower plug 12. Other suitable means, such as hydraulic, solenoid, gear motor, or air cylinder devices, may be used to compress O-ring 14 between lower plug 12 and compression lip 18. By using an automated means for compressing O-ring 14 many drums can be mounted on a rack and simultaneously dip coated.