Apparatus and method for the reduction of printing offset in bidirectional printing devices

Claim 3

The method according to claim 1 including the step of producing a number of dummy print clock signals in accordance with the spacing between the last print clock signal coincident with printed information and the leading edge of the next following scan clock signal.

Claim 4

Apparatus for reducing printing offset in successive print lines in a dot-matrix printer having a bidirectional carriage and sensing means for generating the scan clock signals, and means for deriving print clock signals from said scan clock signals, a first counter connected to receive said scan clock signals and to count cycles thereof, and a second counter connected to receive said print clock signals and count cycles thereof, comprising in combination; a control unit connected to said first and second counters, a control clock generator connected to said first counter and to said control unit, and a print clock generator connected to said control clock generator and to said control unit, said control unit producing a first control signal connected to said first counter after the start of movement of the printer carriage, said first counter counting said scan clock signals for defining an acceleration phase of said printer carriage, said first counter providing a control signal to said control unit when a constant printing speed is reached, said control unit producing further control signals for controlling operation of said control clock generator, said print clock generator and said second counter, said second counter providing a control signal to said control unit at the end of each print line after the last printing position of a line has been reached, said control unit responding to said control signal from said second counter for disabling said control clock generator, said print clock generator, and said first counter after a predetermined interval.

Claim 5

Apparatus for reducing printing offset in successive print lines in a dot-matrix printer having a bidirectional carriage and sensing means for generating the scan clock signals, and means for deriving print clock signals from said scan clock signals, a first counter connected to receive said scan clock signals and to count cycles thereof, and a second counter connected to receive said print clock signals and count cycles thereof, comprising in combination; a control unit connected to said first and second counters, a control clock generator connected to said first counter and to said control unit, and a print clock generator connected to said control clock generator and to said control unit, said control unit producing a first control signal connected to said first counter after the start of movement of the printer carriage, said first counter counting said scan clock signals for defining an acceleration phase of said printer carriage, said first counter providing a control signal to said control unit when a constant printing speed is reached, said control unit producing further control signals for controlling operation of said control clock generator, said print clock generator and said second counter, said second counter providing a control signal to said control unit at the end of each print line after the last printing position of a line has been reached, said control unit responding to said control signal from said second counter for disabling said control clock generator, said print clock generator, and said first counter after a predetermined interval.

Claim 6

Apparatus according to claim 3 wherein said predetermined interval corresponds to the time required for said print clock generator to produce one further print clock signal.