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Automatic Printhead Cleaner

IP.com Disclosure Number: IPCOM000046865D
Original Publication Date: 1983-Aug-01
Included in the Prior Art Database: 2005-Feb-07
Document File: 2 page(s) / 43K

Publishing Venue

IBM

Related People

Bowlds, PA: AUTHOR [+4]

Abstract

A print ribbon malfunction detection system is modified to incorporate an automatic printhead cleaning system. Printing is effected when printing currents are supplied to a print ribbon 13 through a set of electrodes on head 15. The print ribbon 13 is layered so as to include a resistive layer adjacent the head 15, a conductive layer and a thermoplastic pigmented layer which is brought into contact with a writing sheet (not shown) located opposite head 15. Electrode drivers 17 selectively apply print current to various ones of the print electrodes which inject the current into the resistive layer of ribbon 13. The current injection produces localized heating, causing discrete portions of the ribbon's thermoplastic layer to melt and thus bond to the writing sheet to form a print mark on the sheet.

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Automatic Printhead Cleaner

A print ribbon malfunction detection system is modified to incorporate an automatic printhead cleaning system. Printing is effected when printing currents are supplied to a print ribbon 13 through a set of electrodes on head 15. The print ribbon 13 is layered so as to include a resistive layer adjacent the head 15, a conductive layer and a thermoplastic pigmented layer which is brought into contact with a writing sheet (not shown) located opposite head 15. Electrode drivers 17 selectively apply print current to various ones of the print electrodes which inject the current into the resistive layer of ribbon 13. The current injection produces localized heating, causing discrete portions of the ribbon's thermoplastic layer to melt and thus bond to the writing sheet to form a print mark on the sheet. All of the current is collected at a grounded electrode 18. In order to print patterns of print marks and thus form characters or the like, the head 15 and ribbon 13 are moved relative to the sheet and the electrode drivers 17 are gated by a clocked printer control device 19 which is in turn responsive to a character font generator 21. A print ribbon malfunction detection system includes a voltage sensing electrode 25 and threshold detector logic 27 which detect abnormal levels of voltage on the ribbon 13 indicating a ribbon flaw or break. When such over-or under-voltage conditions exist, the switch 29 is actuated disconnecting the voltage source from the electrode drivers 17, thereby preventing damage to the head 15. Logic 31 causes the ribbon to be ther...