Duplex Image Formation With Adaptive Roller Timing Control
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Solution Overview
Problem
Conveyance failures occur in image forming apparatuses when sheets are conveyed by rollers with different peripheral speeds, leading to reduced productivity due to the need to excessively increase conveyance intervals to prevent such failures.
Innovation Solution
The apparatus employs a control unit to manage the conveying speed of sheets through multiple rollers, adjusting the timing of sheet arrival at the image forming region and using a sub conveyance path to avoid simultaneous acceleration/deceleration control during sheet reversal, thereby preventing conveyance failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If acceleration/deceleration control is performed by the registration roller to adjust timing of sending the sheet to the image forming region, then timing precision is improved, but conveyance failure occurs when multiple rollers have different peripheral speeds
Solution Approach 1:
The patent divides the conveyance system into multiple independent roller units (first roller, second roller, third roller) each driven by separate drive sources. This segmentation allows each roller to be controlled independently, preventing conveyance failure while maintaining timing precision through coordinated control of individual rollers rather than relying on a single registration roller for all acceleration/deceleration control.
Solution Approach 2:
The patent implements dynamic control where the control unit adjusts the feeding timing of the second sheet based on the conveyance state of the first sheet. The system dynamically determines when to start acceleration/deceleration control and when to feed the next sheet, optimizing both timing precision and conveyance reliability through adaptive timing adjustments.
2Reliability
If the conveyance interval of the sheet is increased excessively to suppress conveyance failure, then conveyance reliability is improved, but productivity reduces
Solution Approach 1:
The patent uses dynamic timing adjustment where the control unit determines the feeding timing of the second sheet based on the actual conveyance state of the first sheet. This allows the system to maintain optimal conveyance intervals without excessive increases, improving reliability while preserving productivity through adaptive rather than fixed interval control.
Solution Approach 2:
The control unit monitors the conveyance state of sheets and uses this feedback to determine when to feed the next sheet. This feedback mechanism allows the system to adjust timing precisely based on actual conditions, preventing conveyance failures without needing to excessively increase intervals, thus maintaining both reliability and productivity.
3Adaptability or versatility
If a reversing roller is used to reverse the conveying direction of the sheet at the branch point, then double-sided image formation is enabled, but conveyance complexity increases
Solution Approach 1:
The patent segments the conveyance path into a main conveyance path and a sub conveyance path, with separate rollers (first roller, second roller, third roller) assigned to different segments. This segmentation simplifies the reversing mechanism by distributing conveyance control across multiple independent rollers rather than requiring a single complex reversing roller system.
Solution Approach 2:
The patent implements dynamic control of the reversing operation where the control unit determines when to reverse the conveying direction based on the conveyance state of the sheet. The second roller is controlled to rotate in a first direction until the rear end of the sheet passes beyond the branch point, then rotates in a second direction. This dynamic control simplifies the overall system by using straightforward directional control rather than complex mechanical reversing mechanisms.
Data Source
AI summary
An image forming apparatus includes a first drive source of a first roller and a third roller, a second drive source of a second roller, and a control unit, which is configured to perform a first control of changing a conveying speed of a sheet by the first roller from a reference speed in order to adjust timing at which the sheet reaches an image forming region until a front end of the sheet reaches a first position between the first roller and the image forming region. The control unit is configured to control a feeding timing of a second sheet to be fed to a main conveyance path after a first sheet so that the first control is not executed while the first sheet is being conveyed by both the second roller and the third roller.