Browse Prior Art Database

ELECTRONIC INTERFACE FOR LOW SPEED ELECTRONIC PRINTER USING LIQUID CRYSTAL VALVE ARRAY WITH SERIALIZED LINE VIDEO PROCESSING

IP.com Disclosure Number: IPCOM000025571D
Original Publication Date: 1986-Apr-30
Included in the Prior Art Database: 2004-Apr-04
Document File: 2 page(s) / 144K

Publishing Venue

Xerox Disclosure Journal

Abstract

An interface for use with a low cost, low speed non-impact line printer, perhaps a xerographic processing device utilizes the video output stream from a computer or word processor cathode ray tube (CRT) output. The video and sync are separated. The sync signals are used to drive necessary timing signals at start of frame, start of field, end of field, start of line, end of h e , line counting, end of frame, and end of print.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 57% of the total text.

Page 1 of 2

XEROX DISCLOSURE JOURNAL

ELECTRONIC INTERFACE FOR LOW SPEED ELECTRONIC PRINTER USING LIQUID CRYSTAL VALVE ARRAY WITH tnt. CI. G03G 15/00 SERIALIZED LINE VIDEO PROCESSING
Charles D. Wilson

Proposed Classification
U.S. C1. 355/14

An interface for use with a low cost, low speed non-impact line printer, perhaps a xerographic processing device utilizes the video output stream from a computer or word processor cathode ray tube (CRT) output. The video and sync are separated. The sync signals are used to drive necessary timing signals at start of frame, start of field, end of field, start of line, end of he, line counting, end of frame, and end of print.

The video signal is processed by a high speed comparator to drive black/white pixel levels. A pixel line is chopped into 1024/2048 pixels per video line and loaded at high speed into a high speed 1024/2048 serial shift register. The line information is then serially unloaded at low speed 2 megahertz (MHz) into the liquid crystal (LC) valve interface. The 2048 cells of the liquid crystal (LC) valve are turned "on" and the line information is printed on the photoreceptor.

Lines 1 through line 525 are serially processed. Line 2 is processed while line 1 is being printed. Line 2 is not processed until one full field following line I. Lines 3-525 are processed in the same manner. Thus, 525 lines take 525 fields to complete; since each field takes 1/60 of a second, 525 fields rake 8.75 seconds. R full page of print takes 8.75 seconds. Thus printer speed is about 6 pages per minute. (LC) valve array has 2048 cells per 8.5 inch width. crystal liquid The Thus, the "pseodo" resolution IS 240 spots per inch.

Actual resolution is limited by the computer character generator and will be affected by whether or not a 1024 or a 2048 serial shift register is used. A 2048 serial shift register (SSR) is probably limited by technology due to speed. A line of video information takes 56.5 microseconds; therefore, for a 2048 serial shift register (SSR) loaded in real time takes 27 nano seconds per pixel or requires a
36.25 megahertz (MHz) clock. This approaches state of the art. Half that speed, or 54 nano seconds per pixel or 18.125 megahertz (MHz) is achievable.

External fonts are not available, only what is displayed on the cathode ray tube (CRT) is available for printing, However, this means graphics can be displayed if the computer has graphics. If the computer or word processor has multiple internal fonts, these will be printed. Cathode ray tube (CRT) scan lines and matrix dots will not be observed, so actually the printed page quality should exceed the cathode ray tube (CRT) quality. Standard cathode ray tube (CRT) format is 4:3 width:height. Thus, there may be some formatting appearance problems for an 8.5 x 11" page output. Photoreceptor velocity can be increased

Volume I1 Number 2 March/April 1986 81

[This page contains 1 picture or other non-text object]

Pa...