Browse Prior Art Database

Improving Resolution of a Laser Beam Printer

IP.com Disclosure Number: IPCOM000046858D
Original Publication Date: 1983-Aug-01
Included in the Prior Art Database: 2005-Feb-07
Document File: 2 page(s) / 33K

Publishing Venue

IBM

Related People

Froess, RJ: AUTHOR [+2]

Abstract

This article describes a concept of improving resolution of print elements (pels) formed on an electrophotographic medium in a laser beam printer, wherein the width of a pulse in the drive pulse train applied to the printer is adjusted in accordance with adjacent pel patterns in the drive pulse train to provide the desired pel size on the electrophotographic medium. A major cause for the loss of detail is that the phtoconductor's electrostatic field for each pel is modified by nearby pels. Refer to the figure. The normal serial pel data A to the laser exposure system is at a constant period per pel. The electrostatic field of each pel is affected by the nearby pel and results in the print B. Note that pels 5, 6, 10 and 11 are wider than 2 and that 8 is narrower.

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Improving Resolution of a Laser Beam Printer

This article describes a concept of improving resolution of print elements (pels) formed on an electrophotographic medium in a laser beam printer, wherein the width of a pulse in the drive pulse train applied to the printer is adjusted in accordance with adjacent pel patterns in the drive pulse train to provide the desired pel size on the electrophotographic medium. A major cause for the loss of detail is that the phtoconductor's electrostatic field for each pel is modified by nearby pels. Refer to the figure. The normal serial pel data A to the laser exposure system is at a constant period per pel. The electrostatic field of each pel is affected by the nearby pel and results in the print B. Note that pels 5, 6, 10 and 11 are wider than 2 and that 8 is narrower. By adjusting the pel period as in C it is possible to rebalance the size of the pel, as shown in D. The required circuitry (not shown) is quite simple as it should be sufficient to correct only for the effects of the 2 pel before and following each pel transition. The amount of timing shift for each of the 8 possible data patterns is empirically determined by examining print samples. This concept of compensating for spacial distortion between the pel data pattern and the print pattern can be expanded to other printing processes and displays as they also have similar problems. Correction can be made in both axis for distortions caused by spot size, rise/fall tim...