INK JET IMAGING APPARATUS

PROBLEM TO BE SOLVED: To suppress the quantity of ink being consumed for detecting ink by measuring the temperature in the vicinity of a heating element arranged in a specified nozzle within a nozzle group and detecting presence of ink in a liquid chamber based on a measured temperature. SOLUTION: A temperature detecting element 56 is formed, respectively, at parts close to a liquid channel 48 in a liquid chamber 50 on the upper surface 42a of a substrate 42 in the vicinity of nozzle groups 48' at the opposite ends within a nozzle group. When an image is formed on a recording sheet and some quantity of ink is consumed, all heating elements are fed with a specified power for a specified time. Temperature in the vicinity of the heating element does not increase significantly when the liquid channel 48 and the liquid chamber 50 are filled with ink but the temperature detected by a temperature detecting element 56 in the vicinity of the heating element increases abruptly when ink is not present. Temperature variations are stored in a memory and compared with those measured during use of a print head. According to the arrangement, the quantity of ink being consumed for detecting presence of ink in the liquid chamber can be reduced.