| 摘要 |
PURPOSE:To detect an abnormality in every image forming element or an abnormality in a part other than the image forming elements by a simple circuit by a method wherein a plurality of image forming element arrays are arranged on a substrate, and a voltage detection means is connected to a data line through a diode. CONSTITUTION:A control circuit 2 receives a data signal, a clock signal, and a test signal for starting an abnormality detection test from a CPU in a printer body and returns an abnormality signal to the printer body in the presence of an abnormality. When whether a voltage applied to a resistance R is within a specified range is to be detected by a window comparator 10, an abnormality in an image forming device can be detected using a single voltage detection resistance R, the window comparator 10, a test signal detection circuit 12, and the like. An abnormality can be detected for every LED, and an abnormality in a part other than the LEDs can be also detected. If an abnormality exists in only one LED, an abnormality signal can be generated. Alternatively, an abnormality in one LED is passed over, but an abnormality signal can be generated in the presence of abnormality in two or more LEDs. |
