Electronic printing system for imaging thermally sensitive paper
AssigneeSchlumberger Technology Corporation
InventorJ. W. Elliott
Life of this patent
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Abstract
An electronic printing system for imaging lines of pixels on thermally sensitive paper is disclosed. The pixels are imaged in accordance with digital data representing whether a particular pixel is to be imaged or not. The system may also operate in a gray scale mode where the optical density of the imaged pixels varies in accordance with digital data. Other features enable the system to image the lines at a high rate of speed and with a lessened power requirement, thus enabling the use of relatively insensitive thermal paper.
Claims18
A system for imaging lines of pixels on thermally sensitive paper in accordance with stored digital data, comprising:
- a printhead comprising printhead segments each having a plurality of resistor elements corresponding to each pixel in a line and further comprising a segmented printhead shift register and corresponding segmented data latches;
- a line buffer for accepting digital data in parallel form and transmitting the data in serial form;
- a memory for accepting the transmitted serial data;
- a memory controller for storing the transmitted data in the memory and sequentially outputing the data serially to each of the shift register segments in a graphics mode or simultaneously to each shift register segment in a gray scale mode;
- a printhead controller for producing latch pulses for latching the outputs of the shift register segments into the corresponding data latch segments and further for producing separate strobe pulses for driving each printhead segment;
- and
- means for printing pixels in either the graphics mode wherein each bit of the digital data signifies whether a pixel is to be printed or not or in the gray scale mode wherein separate words of the digital data for each pixel represent the desired optical density for that printed pixel.
A system for imaging lines of pixels on thermally sensitive paper in accordance with stored digital data, comprising:
- a printhead comprising a plurality of resistor elements corresponding to each pixel in a line which are heated by strobe pulses in accordance with the state of printhead data latches and further comprising a printhead shift register, the contents of which may be latched into the data latches;
- a line buffer for accepting digital data in parallel form and transmitting the data in serial form;
- a memory for accepting the transmitted serial data;
- a memory controller for storing the transmitted serial data in the memory and sequentially outputting the contents of the memory to the shift register of the printhead;
- a printhead controller for producing latch pulses for latching the outputs of the shift register into the data latches and further for producing strobe pulses causing current to be driven through the resistor elements in accordance with the state of the data latches;
- and,
- means for skewing the data on the thermal paper in order to equalize element usage.
An apparatus for printing lines of pixels representing stored digital data on thermally sensitive paper such that each printed pixel varies in optical density according to a plurality of shades dictated by stored digital data, comprising:
- means for storing element words of digital data with each element word dictating the optical density for a particular printed pixel in a line;
- a printhead having a plurality of resistor elements corresponding to each pixel in a line;
- means for generating a current pulse through the resistor element corresponding to each element word for a number of cycles dictated by the value of the element word, wherein the resistor elements are driven in accordance with the contents of a shift register, the shift register being divided into a plurality of segments which can be loaded simultaneously with bits corresponding to the stored element words;
- and,
- means for sequentially outputting the current pulses to the resistor elements corresponding to each segment of the shift register such that only one segment of the resistor elements is activated at any one time.
An apparatus for printing lines of pixels representing stored digital data on thermally sensitive paper in accordance with bits of stored digital data, comprising:
- a shift register for storing the bits of digital data with each bit corresponding to a particular printed pixel in a line, the shift register being divided into a plurality of segments which can be loaded simultaneously with bits corresponding to the stored digital data;
- a printhead having a plurality of resistor elements corresponding to each pixel in a line;
- means for activating each resistor element according to the value of the corresponding bit of stored digital data by generating a current pulse through the resistor element;
- means for sequentially outputting the current pulses to the resistor elements corresponding to each segment of the shift register such that only one segment of the resistor elements is activated at any one time;
- and,
- means for activating selected pairs of resistor element segments simultaneously when the total number of resistor elements to be activated in the selected pair is less than the total number of resistor elements in a segment.
Dependencies are inferred from the claim text.