| 摘要 |
PURPOSE: To obtain a rapidly and accurately operated temp. monitor device by connecting the electromagnetic call of a printing element to a constant current source during a current stop period and forming a reference signal determining a temp. limit within a comparator by a voltage drop and inputting reference voltage to a data intermediate memory device as a binary logical signal to use this signal as a control signal for the temp. falling of a printing head. CONSTITUTION: When a printing element 1 becomes a non-operative state, a current is stopped and a switch 24 is closed by measuring pulses 23 and an electromagnetic coil 3 is connected to a constant current source 25 and, therefore, a voltage drop is generated in the electromagnetic coil 3 and a reference signal is generated in a comparator 27. The comparator 27 compares difference voltage with reference voltage 28 and logical value H potential and logical value L potential are generated in an output terminal 29 corresponding to that measured voltage is larger or smaller than the reference voltage. The reference voltage 28 corresponds to a temp. value necessary for operating an apparatus and the binary signal of logical value H potential/logical value L potential is stored in a data intermediate memory device 30 and, corresponding to a measured result, it is determined whether or not a printing head must be operated. |
