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Character Generator Select Ring

IP.com Disclosure Number: IPCOM000079190D
Original Publication Date: 1973-May-01
Included in the Prior Art Database: 2005-Feb-26
Document File: 2 page(s) / 44K

Publishing Venue

IBM

Related People

Rooney, JA: AUTHOR [+2]

Abstract

The control system for a dot matrix printer generally includes a character generator, which provides output signals corresponding to the dots which must be printed to develop the desired character. In the case of a seven-column dot matrix printer, it is common to provide a character generator which includes a memory having seven sets of information for each character, one set for each of the seven columns of the matrix. Once the character to be printed has been identified, it is necessary to address each of the seven sets in synchronism with the movement of the matrix print head.

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Character Generator Select Ring

The control system for a dot matrix printer generally includes a character generator, which provides output signals corresponding to the dots which must be printed to develop the desired character. In the case of a seven-column dot matrix printer, it is common to provide a character generator which includes a memory having seven sets of information for each character, one set for each of the seven columns of the matrix. Once the character to be printed has been identified, it is necessary to address each of the seven sets in synchronism with the movement of the matrix print head.

The circuit shown develops seven pulses which are accurately synchronized to the mechanical drive for the print head. The character generator column select ring has seven stages 1-7. The ring is advanced by 600 V sec pulses on line A generated by a pulse emitter, mechanically connected to the drive train for the matrix print head. Synchronism with the stepper motor used to drive the print head is established by a home pulse on line 9, which sets the latch of stage 7.

The output of the AND at each stage is fed to the decoder in so that the decoder output is present for a period, which has the same duration as the length of the emitter pulse on line 8. The latch circuit of each stage is utilized solely to identify which stage was last active. The output of decoder 10 addresses a character generator module, not shown, which has an output that is connected to ...