Appeal No. 1999-1123
Application No. 08/576,915
controlling a current that drives a printer with a LED print
head that has a plurality of printing dots. The control
circuit includes a set of transistors that are connected
together to produce the drive current at an output summing
node. A correction data signal is applied to the transistors
to control the on and off states of the transistors, and a
gradation data signal is applied to the sources of the
transistors. The signals are combined to form the drive
current for the LED print head.
Claim 9 is illustrative of the claimed invention, and it
reads as follows:
9. 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
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