US Patent 7802858 Element board for printhead, printhead and printhead control method

In a printhead having a plurality of printing elements, a shift register which serially receives printing data corresponding to the number of printing elements, a latch which latches the printing data input to the shift register, and a driving circuit which selectively drives the printing elements in accordance with the printing data latched by the latch and a signal representing a driving period, the latch state of the latch is controlled by the signal representing the driving period. The signal representing the driving period and a signal for controlling the latch state of the latch are commonly used to decrease the number of input terminals of the printhead.