Transfer Attitude Correction in Image Forming Apparatus
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Solution Overview
Problem
Existing image forming apparatuses face challenges in accurately correcting transfer sheet skew, leading to issues like 'out of color registration' and image degradation, as previous technologies either fail to correct the left or right end positions correctly or struggle with timing adjustments during skew correction.
Innovation Solution
An image forming apparatus with a transfer attitude correcting section comprising a rotatable base board, registration rollers, and a detecting system that measures the transfer sheet's position and skew, allowing for precise correction of both skew and deviation by rotating and shifting the rollers to align the transfer sheet with the toner image.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a transfer sheet is conveyed and printed under the condition that the transfer sheet is inclined to the conveyance direction (skew), then the blank space between edge portions becomes inclined, but this results in transfer sheet skew being emphasized and interpreted as image skew, degrading image quality
Solution Approach 1:
The patent applies preliminary action by detecting the skew state of the transfer sheet before the printing process and correcting it in advance. The skew detection means measures the skew angle of the transfer sheet as it enters the conveyance path, and the skew correction means (paired rollers) adjusts the sheet's orientation before it reaches the printing unit, ensuring the sheet is properly aligned for high-quality image formation.
Solution Approach 2:
The patent implements feedback through the skew detection means that continuously monitors the transfer sheet's orientation and provides signals to the control unit. The control unit uses this feedback information to adjust the paired rollers' rotation, creating a closed-loop system that dynamically corrects skew conditions to maintain consistent image quality.
2Manufacturing precision
If paired conveyance rollers are rotated to correct skew angle, then transfer sheet skew is corrected accurately, but the left end position or right end position on the leading edge is not always corrected to the regular position, requiring additional parallel movement
Solution Approach 1:
The patent merges the skew correction function and the position correction function into a single integrated mechanism. The paired rollers (skew correction means) are designed to simultaneously correct both the skew angle and the left/right end position deviation in one operation, eliminating the need for separate parallel movement mechanisms and reducing overall device complexity.
3Manufacturing precision
If skew correction is performed by causing transfer sheet to hit paired rollers, then correction accuracy is improved, but timing adjustment becomes troublesome and control complexity increases
Solution Approach 1:
The patent applies self-service by designing the paired rollers to automatically adjust their rotation based on the detected skew angle. The control unit receives skew detection signals and autonomously calculates the appropriate rotation angle for the paired rollers, eliminating the need for complex manual timing adjustments and simplifying the control system while maintaining high correction accuracy.
4Manufacturing precision
If transfer sheet conveyance speed is adjusted during skew correction, then leading edge alignment is improved, but productivity decreases due to speed changes and potential stopping
Solution Approach 1:
The patent applies preliminary action by performing skew correction before the transfer sheet reaches the printing section, during the conveyance phase. The paired rollers correct the sheet's orientation and position in advance, allowing the conveyance speed to be maintained at optimal levels throughout the process without requiring speed adjustments or interruptions that would reduce productivity.
Data Source
AI summary
An image forming apparatus has a transfer attitude correcting section for correcting a transfer attitude of the transfer sheet to receive the toner image and for conveying the corrected transfer sheet to the transfer section with a timing to match with the movement of the toner image. The transfer attitude correcting section includes a roller unit including a base board rotatable around a center of rotation and a registration roller mounted on the base board, a detecting section for detecting a position of the transfer sheet being conveyed by the registration roller; and a control section for control the roller unit based on detection data detected by the detecting section so as to correct a skew of the transfer sheet by rotating the base board and to correct a deviation of a transfer position of the transfer sheet by shifting the registration roller on the base board.