Method and apparatus for electrophotographic laser video modulation and decode for spot fidelity
AssigneeLexmark International, Inc.
InventorGregory Lawrence Ream
Life of this patent
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Abstract
A method of driving a laser device in an electrophotographic machine includes providing a binary image data signal having a first switching rate. A plurality of binary encoded data signals are transmitted over a transmission medium. Each of the encoded data signals is dependent upon the image data signal and has a respective second switching rate lower than the first switching rate. The image data signal is recreated by using the encoded data signals. The laser device is driven with the recreated image data signal.
Claims14
A method of driving a laser device in an electrophotographic machine, said method comprising the steps of:
- providing a binary image data signal having a first switching rate;
- transmitting a plurality of binary encoded data signals over a transmission medium, each of the encoded data signals being dependent upon the image data signal and having a respective second switching rate lower than said first switching rate, each of the binary encoded data signals having a plurality of transitions;
- recreating the image data signal by using the encoded data signals, the recreated image data signal having a plurality of transitions each corresponding to a respective said transition of said binary encoded data signals;
- and
- driving the laser device with the recreated image data signal.
A method of driving a laser device in an electrophotographic machine, said method comprising the steps of:
- providing a binary image data signal having a first switching rate, a plurality of upward transitions and a plurality of downward transitions;
- transmitting a plurality of binary encoded data signals over a transmission medium, each of the encoded data signals being dependent upon the image data signal and having a respective second switching rate lower than said first switching rate, the plurality of binary encoded data signals comprising a first binary encoded data signal and a second binary encoded data signal, the first binary encoded data signal having a plurality of transitions each corresponding to a respective said upward transition of the binary image data signal, the second binary encoded data signal having a plurality of transitions each corresponding to a respective said downward transition of the binary image data signal;
- recreating the image data signal by using the encoded data signals;
- and
- driving the laser device with the recreated image data signal.
A method of driving a laser device in an electrophotographic machine, said method comprising the steps of:
- providing a binary image data signal having a first switching rate, a plurality of upward transitions and a plurality of downward transitions;
- transmitting a plurality of binary encoded data signals over a transmission medium, each of the encoded data signals being dependent upon the image data signal and having a respective second switching rate lower than said first switching rate, the plurality of binary encoded data signals comprising a first binary encoded data signal and a second binary encoded data signal, the first binary encoded data signal having a plurality of transitions each corresponding to a respective said upward transition of the binary image data signal, the second binary encoded data signal having a plurality of transitions each corresponding to a respective said downward transition of the binary image data signal, the second binary encoded data signal comprising a delayed replica of the first binary encoded data signal;
- recreating the image data signal by using the encoded data signals;
- and
- driving the laser device with the recreated image data signal.
An apparatus for driving a laser device in an electrophotographic machine, said apparatus comprising:
- a raster image processor including:
- an image data source configured to output a binary image data signal having a first switching rate;
- and
- a data encoder configured to receive the binary image data signal and transmit a plurality of binary encoded data signals over a transmission medium, each of the encoded data signals being dependent upon the image data signal and having a respective second switching rate lower than said first switching rate;
- and
- a laser scanning unit including:
- a data decoder configured to receive the binary encoded data signals over the transmission medium and recreate the image data signal by using the encoded data signals, said data decoder being configured to perform an extended exclusive-OR operation;
- and
- a laser driver configured to drive the laser device with the recreated image data signal.
An apparatus for driving a laser device in an electrophotographic machine, said apparatus comprising:
- a raster image processor including:
- an image data source configured to output a binary image data signal having a first switching rate;
- and
- a data encoder configured to receive the binary image data signal and transmit a plurality of binary encoded data signals over a transmission medium, each of the encoded data signals being dependent upon the image data signal and having a respective second switching rate lower than said first switching rate;
- and
- a laser scanning unit including:
- a data decoder configured to receive the binary encoded data signals over the transmission medium and recreate the image data signal by using the encoded data signals, said data decoder comprising an exclusive-OR logic gate;
- and
- a laser driver configured to drive the laser device with the recreated image data signal.
Dependencies are inferred from the claim text.