Patent ID: 6351278
Filing Date: 2002-02-26
Classification: B41J,G06K

Abstract:
A current control circuit for controlling a current for driving a print head having a plurality of printing dots, said current control circuit comprising:at least one set of n output transistors, each outputting a driving current, outputs of said n output transistors being connected together at a summing node, and wherein said driving current from said n output transistors is summed at said summing node to produce a driving current for one printing dot of said plurality of printing dots; at least one n-bit register, storing n bits of correction data for the one printing dot and having n outputs connected to said n output transistors to control ON or OFF states of said n output transistors; at least one m-bit register storing m bits of gradation data; and at least one digital/analog converter receiving said m bits of gradation data, having an output connected to sources of said n output transistors, and producing a voltage which is applied to the sources of said n output transistors in accordance with the m bits of stored gradation data, wherein the driving current for the one printing dot is controlled based on a combination of correction data and gradation data.