Image Forming Apparatus Conveyance Error Detection
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Solution Overview
Problem
Existing image forming apparatuses struggle to accurately adjust conveyance distance errors in image forming processes due to the presence of both periodic and aperiodic components, which are not accounted for in the assumption of a constant conveyance distance per rotation of the conveyance roller.
Innovation Solution
An image forming apparatus that includes a conveyor and an image former, with a controller forming test patterns in both the conveyance and sub-scanning directions to detect periodic and aperiodic components of conveyance distance errors by rotating the conveyor by specific amounts and analyzing the patterns formed on the recording medium.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the conveyance distance is adjusted based on the assumption of constant conveyance per rotation, then the adjustment process is simple, but the accuracy of conveyance distance adjustment deteriorates due to unaccounted aperiodic components
Solution Approach 1:
The patent segments the conveyance distance error into two distinct components: periodic errors (from roller eccentricity) and aperiodic errors (from conveyance path shape and sheet recovery forces). By dividing the error analysis into these separate segments, the system can apply different correction strategies for each type, improving overall adjustment accuracy while maintaining reasonable complexity
Solution Approach 2:
The patent implements a feedback mechanism where test patterns are formed on the recording medium, the actual conveyance distance is measured by detecting pattern positions, and the difference between expected and actual positions is used to calculate correction values. This closed-loop feedback enables accurate compensation for both periodic and aperiodic errors
2Measurement precision
If test patterns are formed to detect conveyance errors, then the accuracy of error detection improves, but the complexity of the device and process increases
Solution Approach 1:
The system uses the image forming apparatus itself to create and measure the test patterns, rather than requiring external testing equipment. The recording medium serves dual purposes: as the substrate for image formation and as the medium for error measurement. This self-service approach enables accurate error detection without adding external testing devices
Solution Approach 2:
The test pattern formation process serves multiple functions: it acts as both a calibration procedure and a diagnostic tool. The same image forming mechanism used for production also creates the test patterns, and the detected errors feed back into improving future image formation accuracy, making the system multi-functional
Data Source
AI summary
An image forming apparatus includes a controller configured to, each time an unpaired first pattern element formed on a recording medium is conveyed over a particular distance in a conveyance direction in response to a conveyor rotating by a first amount, control an image former to form a second pattern element to be paired with the unpaired first pattern element thereby forming a first test pattern, and each time an unpaired third pattern element formed on the recording medium is conveyed over a specific distance in the conveyance direction in response to the conveyor rotating by a second amount, control the image former to form a fourth pattern element to be paired with the unpaired third pattern element thereby forming a second test pattern. At least one of the first and second amounts is a non-integer multiple of a rotation amount of the conveyor that makes a single rotation.