Browse Prior Art Database

Laser Erase

IP.com Disclosure Number: IPCOM000086385D
Original Publication Date: 1976-Sep-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 2 page(s) / 53K

Publishing Venue

IBM

Related People

Branham, CE: AUTHOR [+2]

Abstract

In the copier/printer of Fig. 1, xerographic drum 10 is selectively imaged by light reflected off original document 11, or by laser beam 12 as this beam is controlled by text-defining-binary-data, for example as described in U. S. Patent 3,898,627. The resulting electrostatic latent image is then developed or toned by developer 13.

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Laser Erase

In the copier/printer of Fig. 1, xerographic drum 10 is selectively imaged by light reflected off original document 11, or by laser beam 12 as this beam is controlled by text-defining-binary-data, for example as described in U. S. Patent 3,898,627. The resulting electrostatic latent image is then developed or toned by developer 13.

Fig. 2 shows drum 10 "unrolled", to show two working areas 14 and 15, corresponding to the area of contact to a sheet of paper at Fig. 1's transfer station 16. When in the copy mode, laser beam 12 is also used to erase the entire crosshatched border area 17.

It is conventional in a xerographic device to erase slightly inside of areas 14 and 15, for example for a short distance of approximately 0.064 inch.

Thus, for a space of 0.064 inch surrounding the area reflected from original document 11 the photoconductor is subjected to two discharging influences. The first is the laser energy, and the second is the energy reflection from the original document. In most circumstances, this latter effect is reflectance from a white background on original document 11.

Fig. 3 shows a voltage/distance plot of the photoconductor's voltage just before it enters developer 13. To the right of line 18 the photoconductor's voltage is a value such as -190 volts. Between lines 18 and 19 the photoconductor is subject to the two above-mentioned discharging influences. However, the laser's energy is reduced in the 0.064 inch area between lines 18 and 19, such that the total of these...