Browse Prior Art Database

Laser Array Printer

IP.com Disclosure Number: IPCOM000036492D
Original Publication Date: 1989-Oct-01
Included in the Prior Art Database: 2005-Jan-29
Document File: 3 page(s) / 39K

Publishing Venue

IBM

Related People

Ghosh, A: AUTHOR [+2]

Abstract

High resolution (/480 dpi) laser printers operate with a single laser diode and a fast rotating polygonal mirror which deflects the laser beam onto the photoconductor drum which then transfers the image via a transcriber and an electrifier onto the paper. Limitations in such a laser printer design are the required high rotating speed of the polygonal mirror and the fairly complicated design of the imaging optics and the scan optics. The printing speeds are in the range of 2 inches per second. This printing speed can be increased by using laser arrays instead of a single laser. However, the optics limit the number of lasers to approximately 4 so that extremely high speeds are not possible.

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Laser Array Printer

High resolution (/480 dpi) laser printers operate with a single laser diode and a fast rotating polygonal mirror which deflects the laser beam onto the photoconductor drum which then transfers the image via a transcriber and an electrifier onto the paper. Limitations in such a laser printer design are the required high rotating speed of the polygonal mirror and the fairly complicated design of the imaging optics and the scan optics. The printing speeds are in the range of 2 inches per second. This printing speed can be increased by using laser arrays instead of a single laser. However, the optics limit the number of lasers to approximately 4 so that extremely high speeds are not possible.

Our new laser printer design makes use of the possibility to fabricate large laser arrays containing many (>50) closely spaced (50 mm center to center) lasers per laser-bar. A simple calculation shows that for a full line of printing across 20 cm only 40 laser-bars of 5 mm length, containing one hundred 50 mm spaced lasers, are needed. With today's laser technology this is possible to make. The laser bars have to be packaged into a laser printhead, where the connections to the individual lasers can be done with a flip-chip mount (C4) of the laser bars onto a special Si-carrier. This sub-assembly is shown in Fig. 1, where a specially shaped Si-carrier c is fabricated by Si- micro- mechanics, e.g., photolithography and selective etching, and contains a thin film wiring level d with a 50 mm spacing for direct electrical connection to the lasers b. In addition, the Si-sub-carrier contains alignment features e for the laser bars a. The new dry- etching (RIBAE) techniques allow laser mirror etching and integration of alignment features matching the Si-carrier. Integration of electrical devices, e.g., MESFETs or HBTs would allow t...