Printer Control Apparatus for Density Error Correction
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Solution Overview
Problem
Conventional ink jet printers often produce images with uneven density distribution and streaks due to nozzle characteristics, as existing methods for adjusting ink droplet volume are inadequate in preventing these issues.
Innovation Solution
A control apparatus and method that generate a control signal for printers using an arithmetic unit to create an error diffusion processing signal, a multiplier unit to adjust the signal with a correction gain, and a quantizer unit to produce a control signal, effectively managing print density errors and reducing streaks and unevenness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional error diffusion method is used to correct nozzle characteristics, then print density uniformity is improved, but streaks and unevenness still occur due to insufficient correction
Solution Approach 1:
The patent applies parameter changes by introducing a correction gain that modifies the error diffusion output signal. This gain adjusts the magnitude of correction applied to compensate for nozzle characteristics, transforming the correction process from a fixed algorithm to an adjustable parameter-based system that can effectively eliminate streaks and unevenness while maintaining density uniformity
2Manufacturing precision
If ink droplet volume is adjusted to prevent streaks, then print quality is improved, but device complexity increases
Solution Approach 1:
The patent replaces complex mechanical adjustments of ink droplet volume with a signal processing approach. By using arithmetic operations (multiplication by correction gain) on the error diffusion signal, the system achieves precise control of print quality without requiring complex mechanical or physical modifications to the ink ejection mechanism
3Measurement precision
If correction gain is applied to error diffusion output, then density error correction is improved, but risk of overcorrection increases
Solution Approach 1:
The patent implements feedback by using the error diffusion method which calculates correction signals based on the difference between desired and actual print density. The correction gain operates on this feedback signal, allowing the system to automatically adjust correction magnitude based on actual error conditions, preventing overcorrection while maintaining high correction accuracy
Data Source
AI summary
A control apparatus for generating a control signal for controlling a printer on the basis of an input signal includes: an arithmetic unit configured to generate an error diffusion processing signal by subtracting, from the input signal, an error diffusion output signal output from a diffusion matrix that determines a distribution of a print density error; a multiplier unit configured to generate an intermediate signal by multiplying the error diffusion processing signal by a correction gain for controlling a correction amount of the print density error; and a quantizer unit configured to generate the control signal by quantizing the intermediate signal.