Image Forming Apparatus Misregistration Control via Feedback

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Solution Overview

Problem

Existing image forming apparatuses experience misregistration issues between images on the front and rear sides of a recording medium due to positional displacement, which is not effectively addressed by current technologies.

Innovation Solution

An image forming apparatus that includes a second-image adjustment value calculator to detect the position of a first image on a recording medium and calculate an adjustment value for the second image, and a corrective-value calculator to adjust the position of the second image based on the detected position, with the ability to modify the adjustment value based on the actual position of the second image, thereby controlling misregistration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a second-image adjustment value calculator detects the position of a first image and calculates an adjustment value for the second image, then the positional alignment between first and second images is improved, but misregistration on the front and rear sides still occurs due to positional displacement

Engineering Contradiction:
Improvepositional alignment between imagesVSAvoidmisregistration control
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The patent implements a feedback mechanism by detecting the actual position of the first image, calculating an adjustment value, applying it to the second image formation, and then detecting the second image position to calculate a corrective value that modifies the adjustment value for subsequent images. This closed-loop feedback system continuously refines the alignment between front and rear images, eliminating misregistration caused by positional displacement.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system performs preliminary detection of the first image position and calculates the adjustment value before forming the second image. This preliminary action allows the second image to be positioned accurately on the rear side by pre-compensating for any positional displacement that occurs during sheet processing.

Inventive Principle:
Principle #10Preliminary action

2Manufacturing precision

If the adjustment value is calculated based on the detected position of the first image, then the position of the second image is adjusted, but errors in sheet cutting or changes in recording medium dimensions due to temperature variations cause misregistration

Engineering Contradiction:
Improveimage position adjustmentVSAvoidtolerance to sheet cutting errors and temperature variations
Core Design Contradiction:
Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

The feedback mechanism detects the actual position of the first image formed on the sheet, which inherently includes any positional displacement due to sheet cutting errors or thermal expansion. The system calculates an adjustment value based on this actual position, automatically compensating for variations in sheet dimensions and cutting accuracy without requiring separate calibration for different sheet types or temperature conditions.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP4105723B1Image forming apparatus
Publication Date: 2024.07.31 RICOH CO LTD
  • EP4105723B1 patent drawingFigure 1
  • EP4105723B1 patent drawingFigure 2~3
  • EP4105723B1 patent drawingFigure 4

AI summary

An image forming apparatus (100) includes a second-image adjustment value calculator (90) to detect a position at which a first image (G1) is formed on a first face of a recording medium (P) between an instant when the first image (G1) is formed on the first face of the recording medium (P) and an instant when a second image (G2) is formed on a second face of the recording medium (P), and calculate a first adjustment value used to adjust a position at which the second image (G2) is formed on the second face of the recording medium (P), based on the detected position at which the first image (G1) is formed on the first face of the recording medium (P), and a corrective-value calculator (90) to adjust the position at which the second image (G2) is formed on the second face of the recording medium, based on the first adjustment value, and detect the adjusted position at which the second image (G2) is formed on the second face of the recording medium (P). The corrective-value calculator (90) calculates a corrective value used to modify the first adjustment value, based on the detected position at which the second image (G2) is formed on the second face of the recording medium (P).