Browse Prior Art Database

Original Publication Date: 1983-Jun-30
Included in the Prior Art Database: 2004-Apr-04

Publishing Venue

Xerox Disclosure Journal


In automatic reproducing machines it is common to use a drum-type photoreceptor attached to a main frame by means of a center shaft and end hubs which provides a straight forward drive system but requires high precision components to achieve reasonable drum to subsystem tolerances. In this architecture both drum runout and alignment at the inboard/outboard areas may create a problem. These difficulties may be overcome if the photoreceptor drum itself is supported around its periphery at each end by three small rollers spaced so as to completely capture the drum as illustrated in the figure. In the simplest case each pair of rollers (one inboard and one outboard roller) are attached to a common shaft. One set of rollers 14 is used to drive the photoreceptor drum while a second set 10 is a fixed idler set of rollers. A third set of rollers 12 is spring loaded to provide a constant photoreceptor roller force to enable the friction coupling between the drive rolls 14 and the drum 16 to drive the drum. With this arrangement, two of the three sets of rollers remain fixed with reference to the machine frame and the photoreceptor axis is free to move. By locating machine subsystem hardware relative to the fixed rollers the photoreceptor drum rather than the subsystem hardware is guided. The figure illustrates an embodiment where the charging corotron 24, optics 18 and development system 20 are fixed relative to fixed idler roll 10 and the transfer zone 22 is fixed relative to drive roll 14. Spring loaded idler roll 12 is free to provide pressure and take up and drum runout.