Image Position Correction Using Corner Patterns

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Solution Overview

Problem

Existing image forming technologies fail to correct the absolute positional deviation of images on a recording medium with high accuracy under various image forming conditions, which is crucial for achieving higher image quality.

Innovation Solution

An image forming apparatus and method that utilize a correction pattern formed at the corners of the recording medium, detected by sensors, to generate correction data for precise positional adjustment, taking into account image forming conditions such as resolution and sheet size, to accurately correct the absolute positional deviation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a correction pattern is formed at four corners of a recording medium to correct positional deviation, then the image position can be corrected based on detection signals, but the absolute positional deviation of the image with respect to the recording medium is not corrected with high accuracy under various image forming conditions

Engineering Contradiction:
Improveimage position correction accuracyVSAvoidabsolute position accuracy
Core Design Contradiction:
Measurement precisionVSManufacturing precision

Solution Approach 1:

The correction pattern is divided into multiple separate patterns positioned at the four corners of the recording medium. Each corner pattern independently provides positional information, allowing the system to calculate both relative and absolute position deviations through comparative analysis of all four patterns, thereby improving overall positioning accuracy

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A reference position is introduced as an intermediary element that serves as a stable benchmark for comparison. The detection signals from the correction patterns are compared against this reference position to calculate deviation amounts, enabling accurate correction of absolute positional deviations while accounting for various image forming conditions

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If correction patterns are formed and detected to calculate correction values, then image position can be adjusted, but higher image quality requiring accurate absolute position correction is not achieved

Engineering Contradiction:
Improveimage formation efficiencyVSAvoidabsolute position accuracy
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The correction patterns are formed in advance at the four corners of the recording medium before the main image formation process. This preliminary action allows the system to pre-calculate correction values based on the detected positions of these patterns, enabling real-time correction without slowing down the overall image formation productivity

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system implements a feedback mechanism where detection signals from the correction patterns are continuously monitored, correction values are calculated based on the deviation from reference positions, and these correction values are applied to adjust the image position. This closed-loop feedback ensures high absolute position accuracy while maintaining efficient image formation

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP4096205B1Image forming apparatus and image forming method
Publication Date: 2024.05.01 RICOH CO LTD
  • EP4096205B1 patent drawingFigure 1
  • EP4096205B1 patent drawingFigure 2
  • EP4096205B1 patent drawingFigure 3~4

AI summary

An image forming apparatus (100) includes an image forming device (110), an image position determination unit (103), and a reference position determination unit (102). The image forming device (110) forms an image on a recording medium, based on an image forming condition. The image position determination unit (103) determines a position of the image formed on the recording medium by the image forming device (110), based on a detection signal of a pattern formed on the recording medium by the image forming device (110) and reference position information of the pattern on the recording medium. The reference position determination unit (102) determines a reference position of the pattern differently depending on the image forming condition.