Ink jet printing density controller with programmable angle of travel look-up tables for a plotter
AssigneeCalComp Inc.
InventorsBrian L. Spinar, Sandor I. Lengyel
Life of this patent
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Abstract
This invention maintains a selected printed ink drop density in an image recording device such as an X-Y plotter having a cartridge of the type which emits discrete ink droplets onto a recording medium and wherein the cartridge is transported along two axes with respect to the medium. There is sensing apparatus for sensing the two-dimensional velocity vector of the cartridge and control apparatus for regulating the rate at which the cartridge emits the droplets in accordance with the two-dimensional velocity vector. Thus, a given printed dot density on the medium is maintained for different angles of travel of the cartridge.
Claims20
In an image recording device such as an X-Y plotter having a cartridge which emits discrete ink droplets onto a recording medium, said cartridge being transportable along two perpendicular axes of a two-dimensional X-Y coordinate system with respect to said medium, the improvement comprising:
- means for sensing a velocity vector of said cartridge in said two-dimensional X-Y coordinate system;
- and
- means for regulating a rate at which said cartridge emits said droplets in accordance with an acute angle of said velocity vector with one of said two perpendicular axes, whereby to maintain a given printed dot density on said medium for different angles of travel of said cartridge.
In an image recording device such as an X-Y plotter employing an on-demand ink jet cartridge for recording an image onto an ink recording medium in response to received cartridge position command data, said recording device having X and Y shaft encoder means for detecting motion of said cartridge along X and Y axes of a two-dimensional X-Y coordinate system with respect to said recording medium and on-demand ink jet valve control means responsive to a control pulse signal for emitting a single ink droplet for each pulse in said signal, a system for controlling linear density of ink droplets on said medium comprising:
- decoder means for producing a pulse signal from a selected one of aid X and Y shaft encoder means;
- programmable scaling means for changing a pulse repetition rate of said pulse signal by a scale factor to produce said control pulse signal;
- read-only memory means for storing a look-up table relating each angle of travel of said cartridge in a range of angles to a corresponding scaling factor with which said ink jet cartridge produces a given linear printing density on said medium;
- and
- microprocessor means for selecting one of said X and Y axes as a major axis of motion of said cartridge and an angle of travel of said cartridge with respect to said major axis of motion from said cartridge position command data, for selecting a corresponding one of said X and Y shaft encoder means as said decoder means, and for fetching a scale factor for said programmable scaling means appropriate to said angle of travel from said read-only memory.
In an image recording device such as an X-Y plotter having a cartridge which emits discrete ink droplets onto a recording medium, said cartridge being transportable along two axes of a two-dimensional X-Y coordinate system with respect to said medium, a system for regulating linear ink drop density recorded on said medium, comprising:
- means for sensing a parameter of a velocity vector of said cartridge in said two-dimensional X-Y coordinate system;
- look-up table means for providing for a given linear ink drop density factor on said medium a predetermined individual scale factor for each one of a set of plural values of said parameter;
- and
- means for scaling a rate at which said cartridge emits said droplets from a rate of a timing signal in accordance with an appropriate scaling factor provided by said look-up table means, whereby to maintain a given printed ink drop density on said medium for various velocity vectors of said cartridge.
Dependencies are inferred from the claim text.