Printer Control Apparatus for Uniform Print Density
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Solution Overview
Problem
Conventional ink jet printers face issues with uneven print density distribution and streaks due to nozzle characteristics, requiring adjustment of ink droplet volume, which increases memory requirements when trying to enhance image sharpness through error diffusion.
Innovation Solution
A control apparatus and method that utilize a quantizer, multipliers, and calculators to generate control signals by adjusting correction gains and error diffusion inputs, allowing for control of print density and sharpness with reduced memory usage by multiplying signals before and after quantization with adjustment gains.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If correction data is generated and stored for each pixel to adjust ink droplet volume and prevent streaks and unevenness, then print density uniformity is improved, but memory requirements increase significantly
Solution Approach 1:
The patent segments the correction process into two parts: a small correction gain table stored in memory and large correction values applied through multiple multiplication operations. This divides the correction data into manageable segments that require minimal memory storage while achieving comprehensive correction across all pixels.
Solution Approach 2:
The patent changes the parameter representation from storing full correction values for each pixel to storing correction gains that can be applied dynamically. By using correction gains multiplied by error diffusion outputs, the system achieves adaptive correction with minimal stored data, transforming the correction approach from static lookup to dynamic calculation.
2Measurement precision
If error diffusion with multiple correction values is applied to enhance image sharpness, then image sharpness is improved, but memory requirements increase
Solution Approach 1:
The patent segments the sharpness enhancement process by applying correction gains at multiple stages (before and after quantization) rather than requiring multiple full correction tables. This allows error diffusion to be applied with enhanced sharpness control while using only a single small correction gain table in memory.
Solution Approach 2:
The patent performs preliminary correction by multiplying the input signal by the correction gain before quantization, and then performs additional correction by multiplying the control signal by the correction gain again. This preliminary action structure enables sharpness enhancement without requiring memory storage for multiple correction datasets.
Data Source
AI summary
A control apparatus for generating a control signal for controlling a printer on the basis of an input signal includes: a quantizer configured to generate the control signal by quantizing an intermediate signal generated by multiplication, performed by a first multiplier, of the input signal by a correction gain for controlling a correction amount for a print density error, together with subtraction, performed by a first calculator, from the input signal, of an error diffusion output signal output from a diffusion matrix that determines a distribution of the print density error; a second multiplier configured to multiply the control signal by an adjustment gain determined on the basis of the correction gain; and a second calculator configured to generate an error diffusion input signal to be input to the diffusion matrix on the basis of a signal output from the second multiplier.