Image Forming Apparatus Color Registration Control

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Solution Overview

Problem

Conventional image forming apparatuses experience misregistration and color drift during color printing when the printing magnification factor is modified, particularly in duplex printing mode, leading to deterioration in image quality.

Innovation Solution

An image-forming apparatus that adjusts the output-start timing in both main-scanning and sub-scanning directions by modifying scanning velocities in response to changes in the printing magnification factor, using a controlling section to detect and calculate misregistration amounts and adjust the timing accordingly, ensuring precise alignment and registration of colors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the printing magnification factor is modified to accommodate paper size changes in duplex printing, then the printing can be completed on both sides of the paper, but color drift and misregistration occur due to scanning velocity changes

Engineering Contradiction:

Improveduplex printing capabilityVSAvoidcolor registration accuracy

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The system pre-calculates and stores the relationship between magnification factors and scanning velocities in a lookup table before actual printing. This preliminary preparation allows the control section to quickly retrieve the correct scanning velocity for any given magnification factor, ensuring accurate color registration without real-time calculation delays or errors

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The control section uses the stored correspondence data to automatically adjust scanning velocity based on the selected magnification factor. This feedback mechanism ensures that when magnification changes are applied to accommodate duplex printing, the scanning velocity is simultaneously adjusted to maintain proper color alignment and prevent drift

Inventive Principle:

Principle #23Feedback

2Adaptability or versatility

If the scanning velocity is changed to adjust printing magnification, then the printing magnification factor can be modified, but misregistration in printed positions of various colors occurs

Engineering Contradiction:

Improveprinting magnification adjustmentVSAvoidprinted position accuracy

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The system pre-establishes the correspondence between magnification factors and scanning velocities through calculations performed before actual printing operations. This preliminary determination of the optimal scanning velocity for each magnification level ensures that when magnification is adjusted, the associated scanning velocity change is already optimized to maintain position accuracy

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The control section implements a feedback mechanism where the selected magnification factor automatically triggers the retrieval of the corresponding optimal scanning velocity from the stored data. This ensures that scanning velocity is continuously adjusted in response to magnification changes, maintaining accurate printed positions across all color layers

Inventive Principle:

Principle #23Feedback

3Adaptability or versatility

If the scanning velocity is adjusted for magnification change, then the printing magnification factor can be modified, but color printing image quality deteriorates due to unexpected color drift

Engineering Contradiction:

Improvemagnification factor modificationVSAvoidcolor printing image quality

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The system performs preliminary calculations to determine the optimal scanning velocity for each magnification factor and stores these correspondences in advance. This pre-computation ensures that when magnification is modified for duplex printing or other requirements, the associated scanning velocity adjustment is already optimized to prevent color drift and maintain image quality

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The control section uses the pre-stored correspondence data to automatically adjust scanning velocity in response to magnification factor changes. This feedback control ensures that scanning velocity is continuously optimized based on the current magnification setting, preventing color drift and maintaining reliable color printing image quality across all printing conditions

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS7499193B2Image forming apparatus

Publication Date: 2009.03.03 KONICA MINOLTA BUSINESS TECH INC

AI summary

There is described an apparatus, which includes an image-forming section to form a multicolor image on a recording medium by recording the unicolor images in such a manner that the unicolor images overlap each other, based on printing image data sets of them, and a controlling section that determines at least a sub-scanning velocity in a sub-scanning direction relative to the recording medium, corresponding to a printing magnification factor, so as to adjust an output-start timing in the sub-scanning direction for every printing image data set, in response to the sub-scanning velocity determined in advance. Further, the controlling section also determines a main-scanning velocity in a main-scanning direction, corresponding to the printing magnification factor, so as to adjust output-start timings in both the main-scanning direction and the sub-scanning direction for every printing image data set, in response to the main-scanning velocity and the sub-scanning velocity, both determined in advance.