Monitoring system for print head temperatures in thermal ink-jet printer - has temperature sensors located in channel substrate and coupled to comparator circuit for temperature limit control

摘要

The ink jet head has a silicon chip with a line of nozzles that is mounted on a base with a built in reservoir. Heating electrodes in the vicinity of the nozzles are used to generate ink jet bubbles. Temperature sensors (1) located in each nozzle inlet channel provide input to a circuit (8) determining peak (25) and average peak (26) value. The peak value is compared (6) with a local peak value to trigger an alarm (20). A discriminator (7) allows comparison with maximum allowable and minimum allowable chip temperatures (22,23). ADVANTAGE - Provides protection against localised overheating of substrate.