| 摘要 |
PURPOSE:To offer a printer head driver capable of continuing the normal action of two or more dot print heads even when a part thereof is in trouble. CONSTITUTION:When a controller 20 sets control signals S11-S1n at high level, transistors Q11-Q1n enter on-state, and electric currents flow through coils L11-L1n due to the voltage Vdd of a power source, causing dot print heads corresponding to the coils L11-L1n to be driven. At this time, when electric currents due to a voltage V1 flow through diodes D11-D1n and the transistors Q11-Q1n via resistors R11-R1n, the transistors Q11-Q1n enter off-state, causing the collector voltages of transistors Qs1-Qsn, i.e., action detecting signals DOTS1- DOTSn become high level. The controller 20 monitors those action detecting signals DOTS1-DOTSn, and in the case the action detecting signals DOTS1- DOTSn stay at high level even when the transistors Q11-Q1n are set in off-state, it is decided that an abnormal load on a dot print head occurs, and only the action of the abnormally-loaded dot print head is halted. |
