HEATER POWER COMPENSATION FOR TEMPERATURE IN THERMAL PRINTING SYSTEMS

摘要

A method of and apparatus for compensating printing heads which operate, e.g. , in the coincident forces drop on demand printing mode for the effects of ambient print head temperature is disclosed. This helps to maintain consistent drop size over a wide operating temperature range. The apparatus includes a temperature sensor (300) which is affixed to the print head (50) in order to sense the average temperature of the head. The output of the sensor is connected to a device (310) which calculates the power supply voltage required at the said temperature. This result is used to control a programmable power supply (320) which is connected to the heater power supply of the head (50).