Duplex Sheet Reversal Control for Stable Toner Alignment
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Solution Overview
Problem
Existing image forming apparatuses with duplex printing functions face issues in maintaining consistent sheet intervals and reducing paper jams and misprinting due to variations in conveyance timing and individual differences in the reverse conveyance mechanism, leading to potential deviations in toner image positioning.
Innovation Solution
The image forming apparatus incorporates a reverse conveyance unit with a detection system to adjust conveyance speed and direction changes based on detected sheet positions, using a single drive source to manage conveyance speed and direction reversals, ensuring precise timing and reducing mechanical stress on sheets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If a reverse conveyance mechanism is used to enable duplex printing, then automatic sheet reversal and conveyance is achieved, but variations in conveyance timing and sheet interval consistency deteriorate
Solution Approach 1:
The patent employs detection units to monitor the position and conveyance timing of sheets during reverse conveyance. The control unit adjusts the conveyance speed of the reverse conveyance unit based on detected sheet positions, creating a closed-loop feedback system that maintains consistent sheet intervals despite variations in the reverse conveyance mechanism
Solution Approach 2:
The patent dynamically adjusts the conveyance speed of the reverse conveyance unit during operation. By changing the rotational speed of the reverse conveyance rollers based on real-time detection, the system adapts to variations in sheet conveyance timing while maintaining precision
2Productivity
If conveyance speed is increased to improve productivity, then output per unit time increases, but sheet positioning accuracy and toner image alignment deteriorate
Solution Approach 1:
The patent uses dynamic speed adjustment where the conveyance speed is optimized for each sheet based on detection results. The system can operate at higher speeds overall while maintaining precision by adjusting speed individually for each sheet's conveyance phase
Solution Approach 2:
The patent changes the conveyance speed parameter dynamically during the printing process. The control unit adjusts speed parameters based on detected sheet positions and timing, allowing the system to maintain high productivity while ensuring accurate toner image alignment through parameter optimization
3Adaptability or versatility
If multiple drive sources are used to independently control conveyance and fixing, then control flexibility increases, but device complexity and mechanical stress on sheets increase
Solution Approach 1:
The patent combines the drive sources for the reverse conveyance unit and fixing unit into a single integrated drive system. This merging reduces the total number of drive sources and simplifies the mechanical structure while maintaining control flexibility through coordinated control of the unified drive system
Solution Approach 2:
The single drive source serves multiple functions by controlling both the reverse conveyance mechanism and the fixing unit. This multi-functional drive system reduces complexity while maintaining the ability to perform different operations through coordinated control sequences
4Adaptability or versatility
If reverse conveyance is performed to enable duplex printing, then both sides of sheet can be printed, but paper jams and misprinting increase due to timing variations
Solution Approach 1:
The patent uses detection units to monitor sheet position and timing during reverse conveyance. The control unit adjusts conveyance timing based on feedback from these detectors, preventing timing variations that would cause paper jams and misprinting while enabling reliable duplex printing
Solution Approach 2:
The patent performs preliminary detection and adjustment of sheet position before the reverse conveyance operation. By detecting sheet timing in advance and pre-adjusting conveyance parameters, the system prevents paper jams and misprinting before they occur during the duplex printing process
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 approach enhances the accuracy of duplex printing by minimizing misprints and paper jams, maintaining consistent sheet intervals, and improving the fixability of toner images on both sides of the sheet.
Implementation Method 1
a fixing unit including a rotary member that heats the toner image transferred to the recording material and configured to fix the toner image to the recording material
Data Source
AI summary
An image forming apparatus includes an accommodating unit, a feeding unit, an image forming unit, a transferring unit, a fixing unit, a reverse conveyance unit, a re-conveyance unit, first path, a second path, one drive source, a detection unit, and a control unit. The drive source drives a rotary member in the fixing unit and the reverse conveyance unit. The detection unit detects a recording material passing through the second path. The control unit controls the drive source such that the reverse conveyance unit changes a conveyance speed for conveying a second recording material to be conveyed on the second path following a first recording material in a second direction between a first conveyance speed and a second conveyance speed faster than the first conveyance speed based on a detection result of the detection unit that has detected the first recording material passing through the second path.