Conveyance Roller Eccentricity Correction for Image Density
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Solution Overview
Problem
Image forming apparatuses face density unevenness due to eccentricity in sheet conveyance rollers, leading to fluctuations in conveyance amounts during intermittent processing, which existing correction methods fail to adequately address.
Innovation Solution
An image forming apparatus that includes a sheet conveyance device with a sheet conveyance roller and pressure roller, a memory storing profile data for each position along the roller's axial direction to account for eccentricity, and a controller that calculates and applies correction values to ensure consistent conveyance, adjusting the roller's rotation to maintain a predetermined conveyance amount.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single correction value corresponding to sheet width is used, then device complexity is reduced, but manufacturing precision deteriorates due to inadequate correction of conveyance amount fluctuations
Solution Approach 1:
The correction system is segmented into multiple correction values corresponding to different positions in the axial direction of the sheet conveyance roller. Each correction value addresses the eccentricity characteristics at its specific position, enabling precise correction of conveyance amount fluctuations without requiring complex mechanical modifications
Solution Approach 2:
Correction values for each axial position are pre-calculated and stored in memory based on the roller's eccentricity profile. During operation, the controller automatically selects and applies the appropriate correction value based on the current axial position, eliminating the need for real-time complex calculations or mechanical adjustments
2Manufacturing precision
If multiple correction values for different axial positions are implemented, then manufacturing precision improves, but device complexity increases
Solution Approach 1:
The controller monitors the axial position of the sheet conveyance roller and dynamically selects the appropriate correction value from memory based on this feedback. This automated feedback mechanism enables precise correction across multiple positions without requiring complex mechanical switching or manual intervention
Solution Approach 2:
The mechanical complexity of implementing multiple correction mechanisms is replaced by an electronic control system. The controller uses software-based correction value selection and application, substituting what would otherwise require multiple physical correction mechanisms with a single electronically controlled system
Data Source
AI summary
An image forming apparatus includes a sheet conveyance device; an image forming device including a sheet conveyance roller and a pressure roller; a memory; and a controller. The memory stores profile data indicating variation in conveyance amount in a circumferential direction due to eccentricity of the conveyance roller. The controller calculates, in intermittent conveyance processing, a correction value based on corresponding profile data for each of positions included in a width of an image to be formed in next image forming processing, the correction value being a difference between a predetermined conveyance amount and an actual conveyance amount; corrects a reference amount of rotation by a representative value of calculated correction values to calculate a corrected amount of rotation, the reference amount being an ideal amount of rotation of the conveyance roller that conveys a sheet by the predetermined conveyance amount; and rotates the conveyance roller by the corrected amount.