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Print Head Adjustment

IP.com Disclosure Number: IPCOM000046458D
Original Publication Date: 1983-Jul-01
Included in the Prior Art Database: 2005-Feb-07
Document File: 2 page(s) / 28K

Publishing Venue

IBM

Related People

Castle, WH: AUTHOR

Abstract

A print head containing vertically aligned electrodes is vertically adjusted with respect to a rounded platen by observing the voltage variations in the individual constant-current electrode drive circuits.

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Print Head Adjustment

A print head containing vertically aligned electrodes is vertically adjusted with respect to a rounded platen by observing the voltage variations in the individual constant-current electrode drive circuits.

Print head 11 contains plural, vertically aligned electrodes 13 which are embedded in a plastic block 15. The end 17 of the electrodes are shaped to conform with the cylindrically shaped document platen 19. Printing is effected by contacting the ends 17 of the electrodes 13 with a ribbon (not shown) which contacts a document (not shown) located on the platen 19 and by applying current pulses to the electrodes. The current pulses cause ink located on the ribbon to tackify and transfer to the document.

Poor print quality, ribbon burn through and possible head damage is caused when the print head 11 is not correctly oriented with the platen 19. If the print head 11 is located high with respect to the platen 19 as depicted, the voltage required to print increases for those electrodes 17 located at the top of head 11. Likewise, if head 11 is adjusted too low, additional voltage is required by the lower electrodes. Since the electrode driver varies the voltage on each of the electrodes to provide a constant current printing pulse, the voltage on the top and bottom electrodes may be monitored to facilitate the vertical alignment of the head 11 with respect to the platen 19. Thus, head 11 is moved and the print voltages are monitored to insure pr...