Abstract: Circuit board 10 is of substantially rectangular shape, provided in the upper half of the juxtaposed face 13 with a substantially circular test terminal 20. In the lower half are provided a plurality of substantially rectangular terminals 21-27, arrayed in two rows, i.e., an upper and lower row, the upper row containing an I/O terminal 21 for data input/output, a power supply terminal 22 for supplying power, and a chip select terminal 23 for input of a chip select signal CS. The lower row of juxtaposed face 13 contains a ground terminal 24, a read/write terminal 25 for inputting read/write control signals W/R, a clock terminal 26 for inputting a clock signal CLK, and a ground terminal 27.

Abstract: A print head includes rows of plural nozzles, from which ink drops are ejected. A plurality of driving elements are respectively associated with each nozzle. A plurality of switching circuits are respectively associated with each row of nozzles. Each switching circuit is provided with a plurality of switching elements, respectively associated with each driving elements. Each switching element supplies a signal to drive an associated driving element. Each of a plurality of detectors detects a condition of associated nozzles and outputting a detecting signal in accordance with the detected condition. A controller drives the print head based on the detecting signals. At least one signal line transmits the detecting signals to the controller in a time sequence manner. The number of the signal line is less than the number of the detectors.

Abstract: A print head activation circuit for a wire dot printer includes a first switch and a second switch. A CPU produces a printing timing control signal. A first driving signal-generating circuit produces a first driving signal pulse having a pulse width T.sub.1 in response to the printing timing control signal. A delay circuit delays the first driving signal. A second driving signal-generating means produces a second driving signal pulse having a pulse width T.sub.2 in response to the leading edge of the delayed first driving signal. The first switching means is connected with a DC power supply. The first switching means is also connected with one terminal of each actuator coil of the print head. The second switching means is connected between a second terminal of the actuator coil and ground. The second driving signal-generating means is operated in response to the delayed first driving signal. The delay time .DELTA.