Patent ID: 6958765
Filing Date: 2005-10-25
Classification: H03K,H03M,H04N

Abstract:
1. A laser printer that performs a printing operation by controlling a laser beam emitted by a printer engine on the basis of serial video data specifying width of the laser beam with respect to a scanning direction corresponding to tones of dots, said laser printer comprising: a first parallel-to-serial converting unit capable of being triggered for operation by the leading edge or the trailing edge of a predetermined clock signal to convert first parallel data into an initial serial data pulse of a resolution lower than a resolution needed by the serial video data and having pulse width that changes in a unit length corresponding to a period of the clock signal; a second parallel-to-serial converting unit capable of being triggered for operation by the trailing edge of the clock signal if the first parallel-to-serial converting unit is triggered by the leading edge of the clock signal or by the leading edge of the clock signal if the first parallel-to-serial converting unit is triggered by the trailing edge of the clock signal to convert second parallel data into a pulse width adjusting serial data pulse having pulse width that changes in a unit length corresponding to the period of the clock signal; a pulse width adjusting unit for adjusting width of the initial serial data pulse between at least one of the edges of the initial serial data pulse and an edge of the pulse width adjusting serial data pulse; a serial data output unit that provides one of the serial data pulse having a pulse width adjusted by the pulse width adjusting unit or the initial serial data pulse as a provided serial data pulse; an n-stage clock signal delaying unit (n is a natural number) including a plurality of signal delay devices placed in a predetermined clock signal line to obtain delayed pulses at a plurality of delayed times by delaying a leading and a trailing edge of the clock signal; an n-stage delayed pulse gate (n is a natural number) that passes a delayed pulse of time specified by a timing signal specifying the time of the delayed pulse; a delayed pulse input unit for applying the delayed pulse passed the nth delayed pulse gate to a clock signal line of an (n+1)th clock signal delaying unit; a delayed clock selecting unit for selecting a delayed pulse according to a delayed clock selection signal specifying one of the n-stages of delayed pulse gates to increase pulse width of the provided serial data pulse in a unit corresponding to 1/N (N=n+1) of half the period of the clock signal; and a high-resolution serial data pulse signal output unit for providing a high-resolution serial data pulse formed by adjusting the pulse width of the provided serial data pulse between at least one of the edges of the provided serial data pulse provided by the serial data output unit and the edge of the delayed pulse selected by the delay clock selecting unit.