Print head and image forming apparatus

A print head comprising:

• a plurality of current-driven non-single crystal light emitting elements arranged in a line;
• a plurality of thin film transistors that is provided in one-to-one correspondence with the plurality of light emitting elements and each supplies a driving current to a corresponding one of the plurality of light emitting elements;
• a detector that detects, when one of the plurality of light emitting elements corresponding to one of the plurality of thin film transistors emits light, an output voltage of the one of the plurality of thin film transistors;
• and a hardware processor that determines a control voltage to be applied to each of the plurality of thin film transistors when next light is emitted according to the output voltage of the one of the plurality of thin film transistors detected by the detector and a driving current to be supplied by each of the plurality of thin film transistors to cause each of the plurality of light emitting elements to emit light with a target light amount, wherein
• the hardware processor determines, for each of the plurality of thin film transistors based on a Vsd-Id characteristic of a corresponding one of the plurality of thin film transistors, a control voltage corresponding to a combination of the output voltage Vsd detected by the detector and a driving current amount Id for causing one of the plurality of light emitting elements corresponding to the one of the plurality of thin film transistors to emit light with the target light amount as the control voltage.