Ribbon fault detection system
US4685818A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 16, 1985 |
| Grant date | Aug 11, 1987 |
| Priority date | — |
| Expiry date | Sep 16, 2005 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB41J35/36
- WIPO fieldTextile and paper machines
- WIPO sectorMechanical engineering
Abstract
A ribbon fault detection system within an impact printer has a pair of resilient electrical contacts disposed in spaced-apart relation across the width of an ink ribbon within each of a pair of ribbon guides located between the opposite ends of a print station and a pair of spools for receiving the opposite ends of the ink ribbon and driving the ink ribbon. Each of the electrical contacts which is silicone coated to minimize ink migration and which is normally held out of engagement with a mating contact due to engagement by the ribbon is coupled in parallel with the other resilient electrical contacts so that closure of any one of the resilient electrical contacts onto its mating contact will generate an indication of a ribbon fault condition. A ribbon fault condition which may be caused by a folded ribbon or other undesired condition and which closes one or more of the contacts turns on a transistor via an operational amplifier having a capacitor coupled thereacross to provide a desired delay in turning on the transistor and which is coupled through a Zener diode to further control the conduction and nonconduction of the fault indicating transistor.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.