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Browse Prior Art Database

High Performance Matrix Print Head

IP.com Disclosure Number: IPCOM000050817D
Original Publication Date: 1982-Dec-01
Included in the Prior Art Database: 2005-Feb-10
Document File: 3 page(s) / 51K

Publishing Venue

IBM

Related People

Ebert, WS: AUTHOR [+2]

Abstract

Some electrochemical and electrolytic printers require a print head capable of printing 240 dots per inch over a full eleven-inch page width. Such a print head would have in excess of 2500 print elements, with dimensions in the range 0.004 to 0.008 inch, all of which would be positioned in an eleven-inch strip less than 0.10 inch wide. A connection must be made from each print element to a decoder/driver integrated line spacing requirements, 0.0083 inch center to center, with lines approaching from two sides of the active strip.

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High Performance Matrix Print Head

Some electrochemical and electrolytic printers require a print head capable of printing 240 dots per inch over a full eleven-inch page width. Such a print head would have in excess of 2500 print elements, with dimensions in the range
0.004 to 0.008 inch, all of which would be positioned in an eleven-inch strip less than 0.10 inch wide. A connection must be made from each print element to a decoder/driver integrated line spacing requirements, 0.0083 inch center to center, with lines approaching from two sides of the active strip.

Multilayer ceramic (MLC) techniques can meet the conductor density requirements, but MLC suffers from excessive tolerance build-up over long distances. This tolerance build-up must be compensated for with complicated and expensive additional processing. Photolithographic techniques can easily meet the conductor density requirements, but are normally limited to planar geometries Which cause major problems with bringing the paper into contact with the print elements.

Fig. 1 shows a more suitable, non-planar geometry which can be constructed by employing standard planar photoprocessing, sequentially on the various surfaces. Fig. 2 shows the three main pieces making up the print head of Fig. 1. The three pieces in Fig. 2 are made by casting and firing a slurry of a recrystallizable glass frit, which has a recrystallization and sintering temperature in the range 700 to 1000 degrees C. After the first firing, this material is dimensionally stable during subsequent firings. Also, after the first firing, these pieces are ground and lapped to pr.ovide accurate dimensions, good planarity, and good surface finish. The larger of the three pieces is then metallized and photolithographically etched on both sides to provide the conductor lines necessary to connect the IC chips with the I/O pads and print head elements. This process is similar to normal metallized ceramic (MC) processing with the exception that either the top or bottom chrome (Cr) layer may be eliminated or substituted with another metal to improve metal adhesion, limit Cu diffusion during later firings, or simplify later processing. Note that the substrate is larger than required for the finished head in one direction. This is necessary because the conductor lines from the IC chips to the active print element area must extend all the way to the final edge line and the photolith processes break down near the edge of the substrate. The excess can be trimmed off either immediately before or after assembly with the two smaller pieces, as required by processing convenience. Trimming can be a...