Image Forming Apparatus Sheet Registration Timing Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing image forming apparatuses face challenges in maintaining accurate image positioning on sheets of varying thickness due to variations in registration roller dimensions caused by wear or heat expansion, leading to potential image deviation.
Innovation Solution
An image forming apparatus that includes a current detection system to monitor the transfer current and adjust the feed start timing of the registration roller pair based on the arrival timing of the sheet at the transfer nip, ensuring precise alignment and image transfer positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the registration roller pair dimensions are changed to accommodate sheets of varying thickness, then image positioning accuracy deteriorates due to roller wear and heat expansion
Solution Approach 1:
The patent employs feedback control by detecting the arrival timing of sheet leading edges using current detection from the transfer roller, then adjusting the feed start timing of the registration roller pair accordingly. This closed-loop system continuously compensates for timing deviations caused by roller wear or thermal expansion, maintaining image positioning accuracy despite dimensional changes in the registration roller pair.
Solution Approach 2:
The system dynamically changes the feed start timing parameter based on detected sheet arrival timing. By adjusting this temporal parameter in response to actual sheet conveyance conditions, the system compensates for dimensional variations in the registration roller pair without requiring physical reconfiguration of the roller dimensions themselves.
2Manufacturing precision
If additional sensors are added to detect sheet position accurately, then image positioning accuracy improves, but device complexity increases
Solution Approach 1:
The transfer roller serves a dual function: it both transfers the toner image to the sheet and acts as the detection means for sheet arrival timing. By utilizing the existing current flow through the transfer roller for detection purposes, the system eliminates the need for separate detection sensors, reducing device complexity while maintaining accurate timing detection capability.
Solution Approach 2:
The transfer roller is designed to perform multiple functions simultaneously: image transfer and sheet position detection. This multi-functional approach allows the system to achieve accurate image positioning without adding dedicated detection sensors, thereby avoiding increased device complexity while maintaining precision.
3Productivity
If the registration roller pair conveys sheets at higher speed to increase productivity, then productivity improves, but image positioning accuracy deteriorates due to timing deviation
Solution Approach 1:
The system uses feedback from current detection to monitor actual sheet arrival timing at the transfer portion. Regardless of conveyance speed variations, the feed start timing is continuously adjusted based on this feedback, ensuring that image positioning accuracy is maintained even when productivity is increased through faster sheet handling.
Solution Approach 2:
The feed start timing is made dynamic rather than fixed, allowing real-time adjustment based on actual sheet conveyance conditions. This dynamic timing adjustment enables the system to adapt to varying conveyance speeds while maintaining precise image positioning, decoupling productivity improvements from positioning accuracy degradation.
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 solution effectively maintains image alignment across sheets of different thicknesses by adjusting the registration roller pair's timing, reducing image deviation and eliminating the need for precise roller dimensioning and additional sensors, thus enhancing print quality and reducing costs.
Implementation Method 1
a current detection portion configured to detect a current flowing through the transfer portion
Data Source
AI summary
An image forming apparatus includes an image bearing member, a transfer portion configured to transfer an image borne on the image bearing member to a sheet, a current detection portion configured to detect a current flowing through the transfer portion, a conveyance portion configured to convey the sheet to the transfer portion, a driving portion configured to drive the conveyance portion, and a controller configured to acquire an arrival timing at which a leading edge of a preceding sheet has arrived at the transfer portion based on a detection result of the current detection portion, and control the driving portion in response to the arrival timing in a state where a succeeding sheet that follows the preceding sheet is conveyed by the conveyance portion.