Sheet Width Detection Control for Duplex Image Alignment
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Solution Overview
Problem
Existing image forming apparatuses suffer from misalignment of images on sheets due to inaccuracies in detecting the side edge positions, particularly at the trailing edge, leading to positional discrepancies between the leading and trailing edges of the sheet, especially during double-sided printing.
Innovation Solution
The apparatus employs CIS sensors to detect side edge positions at the center of the sheet in the conveyance direction, adjusting image positions based on these central detections to minimize misalignment, thereby improving positional accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the side edge position at the leading edge of the sheet is detected by the CIS sensor, then the writing position can be controlled based on the detection result, but the image becomes more greatly misaligned with respect to the sheet at the trailing edge portion of the sheet than at the leading edge portion of the sheet
Solution Approach 1:
The patent detects the side edge position at the leading edge of the sheet in advance, and then uses this detection result to control the writing position. This preliminary detection allows the system to proactively adjust the image writing position before the trailing edge misalignment occurs, rather than attempting to correct it after the fact.
Solution Approach 2:
The patent implements a feedback control mechanism where the CIS sensor detects the actual side edge position of the sheet, and this detection result is fed back to control the writing position of the image. The system continuously monitors and adjusts the writing position based on the detected sheet position, creating a closed-loop control system that compensates for sheet positioning variations.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method reduces image misalignment in the sheet width direction by using center-based detection to correct image positions, enhancing the accuracy of images formed on both sides of the sheet.
Implementation Method 1
a width position detection unit configured to detect a width position of the sheet in a sheet width direction
Implementation Method 2
the position of the side edge of the sheet is read by the CIS sensor
Data Source
AI summary
An image forming apparatus includes an image bearing member, an image forming unit, a transfer unit, a conveyance unit, a width position detection unit, and a control unit. The width position detection unit detects a width position of a sheet in a sheet width direction. The control unit acquires a first width position of a first sheet based on a detection result of the width position detection unit, and adjust a width position of an image to be transferred to a second sheet subsequent to the first sheet on the image bearing member based on the first width position, where the first width position is a width position of the first sheet at a first conveyance direction position that is a position of the first sheet located in a central region among three regions into which the first sheet is equally divided in a sheet conveyance direction.