Method and apparatus for controlling the thermal head drive
US5690437A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 1, 1995 |
| Grant date | Nov 25, 1997 |
| Priority date | — |
| Expiry date | Dec 1, 2015 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB41J3/46
- WIPO fieldTextile and paper machines
- WIPO sectorMechanical engineering
Abstract
The present invention provides a method and an apparatus for driving and controlling a thermal head used in a printing device, such as a tape printer, in response to the temperature variations of the printing device environment and the thermal head. According to the present invention, in the printing operation of the tape printer, measurements are made of the initial temperature T1 immediately after the power is switched on, the temperature prior to printing T2, and the ambient temperature of the thermal head each time the thermal head prints T3 (i). If the temperature difference between the initial temperature T1 and the temperature prior to printing T2 is small, the duration of the current signals provided to the thermal head is controlled in accordance with the temperature prior to printing T2, which is the most recently measured thermal head ambient temperature best reflecting the printing device environmental temperature. If the difference is large, the duration is controlled in accordance with the initial temperature T1 which then best reflects the environmental temperature. If the rate of the increase in temperature during printing T3(i) is large, the duration is controlled …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.