Sheet Conveyance Control for Sub-Scanning Obliqueness Correction

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Solution Overview

Problem

Image forming apparatuses face issues with sub-scanning obliqueness due to misalignment among registration rollers, secondary transfer nip, and fixing nip, leading to image defects and distortion, especially with long sheets, as existing registration displacement control methods often result in incomplete correction of sheet position.

Innovation Solution

An image forming apparatus and method that includes a sheet conveying member and a hardware processor for controlling the displacement of the sheet conveying member, where the processor detects the sheet edge after displacement has started and terminates the displacement based on the detected result to ensure the edge reaches a target position, allowing for accurate correction of sub-scanning obliqueness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If registration rollers are displaced based on detected sheet edge position, then sheet position correction is improved, but the sheet edge may still be shifted from the reference position when displacement is terminated

Engineering Contradiction:

Improvesheet edge position detection accuracyVSAvoidsheet position alignment accuracy

Core Design Contradiction:

Measurement precisionVSManufacturing precision

Solution Approach 1:

The system continuously detects the sheet edge position during displacement and uses this feedback to dynamically adjust the displacement amount, ensuring the sheet edge reaches the target position accurately

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system detects the sheet edge position before displacement begins and calculates the required displacement amount in advance, then performs the displacement while continuously monitoring to ensure accurate positioning

Inventive Principle:

Principle #10Preliminary action

2Reliability

If registration rollers are displaced to correct sheet position, then sub-scanning obliqueness is reduced, but image defects and distortion may still occur due to incomplete correction

Engineering Contradiction:

Improvesub-scanning obliqueness correction effectivenessVSAvoidimage defects and distortion

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The system uses continuous detection of sheet edge position during displacement to provide feedback, ensuring the correction is complete and accurate, thereby preventing image defects and distortion

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system replaces traditional mechanical alignment methods with a control system that uses detection and calculation to determine precise displacement amounts, achieving more accurate correction

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS11144002B2Image forming apparatus and conveyance control method

Publication Date: 2021.10.12 KONICA MINOLTA INC

AI summary

The image forming apparatus includes a transfer section that transfers an image to a sheet; a sheet conveying member that is provided on an upstream side of the transfer section in a conveying direction of the sheet and that conveys the sheet; and a hardware processor that controls displacement of the sheet conveying member such that the sheet is displaced in a width direction of the sheet. The hardware processor causes a detector that detects an edge of the sheet in the width direction to detect the edge of the sheet after displacement of the sheet conveying member has been started, and causes the displacement to be terminated on the basis of the detected result such that the edge of the sheet reaches a target position.