| 摘要 |
PURPOSE:To prevent the drive of a parasitic circuit by printing currents by a method wherein diods connected in series with a printing heating element and a parasitic circuit reaching a resistor, which does not generate heat originally, through a semiconductor substrate are separated. CONSTITUTION:A plurality of P type island regions 31-33 mutually separated are formed on one surface of an N type slicon substrate 30, N<+> type regions 34-36 are made up in islands, and the diode arrays D11-D33 are built up. The transistors Q1-Q3 of a picture signal switch are connected to the P type island regions 31- 33, and exothermic resistors R11-R33 are connected to the N<+> type reions 34-36. When the Q1 is turned ON and the R11 is heat-generated, since the junction of the diode D11 is conducted at the interface of the P region 31 and the N<+> region 34, the P region 31 of a parasitic circuit and the N type substrate 30, the P region 32 and the N<+> region 35 are completely separated, and the parasitic PNPN circuit is not driven. Thus, the drive of the parasitic circuit by printing currents can be prevented, and the dots of a head can be integrated. |
