Browse Prior Art Database

Remote Readout Drum Gage

IP.com Disclosure Number: IPCOM000043016D
Original Publication Date: 1984-Jun-01
Included in the Prior Art Database: 2005-Feb-04
Document File: 3 page(s) / 65K

Publishing Venue

IBM

Related People

Berner, DM: AUTHOR [+4]

Abstract

Clearances between elements arrayed around the periphery of a drum in a xerographic copier, printer or the like, are determined by a fixture configured to replace the drum in the unit. The fixture has a carriage movable parallel to the drum axis and which retains a radially-oriented micrometer probe coupled for remote readout. A calibration block is removably attachable to the fixture. Typical clearances measured in a xerographic device relative to the drum surface include spacing to the developer magnetic roll, coronas and cleaning station. Accurate measurement of these clearances is important so that characterization of the electrophotographic process is established at known physical parameters around the drum. Electrophotographic process performance can vary depending upon such clearances.

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Remote Readout Drum Gage

Clearances between elements arrayed around the periphery of a drum in a xerographic copier, printer or the like, are determined by a fixture configured to replace the drum in the unit. The fixture has a carriage movable parallel to the drum axis and which retains a radially-oriented micrometer probe coupled for remote readout. A calibration block is removably attachable to the fixture. Typical clearances measured in a xerographic device relative to the drum surface include spacing to the developer magnetic roll, coronas and cleaning station. Accurate measurement of these clearances is important so that characterization of the electrophotographic process is established at known physical parameters around the drum. Electrophotographic process performance can vary depending upon such clearances. In some cases, it is possible to measure these clearances with a micrometer mounted on a shaft attached in place of the drum, but on the drum centerline. The micrometer is zeroed at the drum radius dimension by a gage block so that any incremental micrometer displacement required to contact a surface arrayed around the normal drum periphery establishes the drum-to-surface clearance. The drum gage assembly shown allows the user to install the drum gage into the xerographic device, where direct micrometer dial reading is difficult or undesirable, and read out clearances remotely. A gage assembly is formed of end plates 10 and 11, coupled by shafts 14, 15 and 16, the latter having an offset position to accommodate calibration block 20. Carriage 22 is movable on shafts 14-15 parallel to the drum axis. Although shown as a slidable arrangement, carriage 22 can accept a screw drive for power or automatic axial positioning. Carriage 22 is shown in greater detail in Fig. 2, and mounts a conventional probe, such as an electromechanical linear displacement measurement gage head. The probe is connected at output 26 through cable 28 into remote readout unit 30 (Fig. 1). In a typical example, probe 24 has a travel range of Å1.50 mm from nominal. Carriage fixture 22 locates probe 24, and is slidable on shafts 14 and 15 along the drum centerline axis by means of slide bearings 31 and 32. Frequently, there a...