| 摘要 |
PURPOSE:To prevent generation of ground smearing or the like by checking a control voltage to a corresponding control electrode when no black signal is contained in the image signal with the preset number of dots. CONSTITUTION:A black screen signal detection circuit 20 detects a black image signal among image signals for each block having the present number of image dots and inputs it into a timing control circuit 7. Then, the timing control circuit 7 applies a voltage to control electrodes C1 and C2, for example, for the A1 area containing a black signal as did before and combines it with the application of a voltage to the main electode A12 to perform a printing according to an image signal. In the B1 area containing none of the black signal, the control voltage won't be applied to the control electrodes C2 and C3 by a command from a black image signal detection circuit 20 and instead, the voltage is applied to the main electrode B13 alone. Because there is no discharge in the B1 area between the main electrode 13 and a recording body, elimination of ground smearing is enabled. |
