| 摘要 |
PROBLEM TO BE SOLVED: To provide a printing apparatus which executes printing by correcting resistance value variations of heating elements, thereby maintaining a discharge function uniform at all times. SOLUTION: A printing apparatus 1 has a special circuit unit consisting of a switch 5, a switch 6, a capacitor 7 and a voltage-detecting circuit 8 in addition to a printing head 2, a control device 3 and a power source 4. At a printing process, a CPU 16 of the control device 3 closes the switch 5 and opens the switch 6 to receive a printing signal 22 from an external apparatus by an I/O controller 21, and outputs a control signal based on the printing data 22 to a driving circuit 13. Meanwhile, in measuring a resistance value of a heating element, the CPU closes the switch 5 and the switch 6 to turn off the driving circuit 13 and charges the capacitor 7 by the power source 4. Then, the CPU opens the switch 5 to sequentially drive to discharge the heating elements via the driving circuit 13 with a charged potential of the capacitor 7. A voltage after a predetermined time is detected by the voltage- detecting circuit 8 and, the resistance value is checked and stored in an E2ROM 19. Driving of each heating element is corrected on the basis of the stored resistance value when printing is conducted.
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