Dual Image Forming Unit Registration via Drawing Cycle Adjustment
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Solution Overview
Problem
Partial misregistration occurs between images formed by two image forming units on a sheet due to varying sheet transport speeds during the secondary transfer process, leading to imperfect image alignment.
Innovation Solution
An image forming system that includes a first and second image forming unit with intermediate transfer media, a sheet transport portion, and a processor that adjusts the drawing cycle of images based on detected misregistration to align images at the same position on the sheet, using either absolute or relative position correction methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If two image forming units are used to form toner images on a sheet via secondary transfer at two positions, then the color gamut is extended and image quality is improved, but partial misregistration occurs between the images due to sheet transport speed changes
Solution Approach 1:
The system performs preliminary measurement of the sheet transport speed during the sheet feeding process before the actual image formation. This advance measurement allows the control unit to calculate and apply appropriate drawing cycle adjustments in advance, preventing misregistration before it occurs during the secondary transfer process.
Solution Approach 2:
The system dynamically adjusts the drawing cycle parameter of the image forming units based on the measured sheet transport speed. By changing the drawing cycle in accordance with the actual sheet transport speed, the system compensates for speed variations and maintains precise image alignment between the two image forming units during secondary transfer.
2Manufacturing precision
If the sheet transport speed is maintained constant, then image alignment is improved, but the system cannot accommodate variations in sheet feeding conditions
Solution Approach 1:
The system incorporates a feedback mechanism where the sheet transport speed is measured during sheet feeding, and this measured information is fed back to the control unit. The control unit then uses this feedback to adjust the drawing cycle of the image forming units, creating a closed-loop system that adapts to actual sheet feeding conditions while maintaining image alignment precision.
Data Source
AI summary
An image forming system includes a first image forming unit including plural first image forming portions and a first intermediate transfer medium to which a toner image formed by the plural first image forming portions is primarily transferred, a second image forming unit that is provided on a downstream side of a sheet transport direction with respect to the first image forming unit and that includes plural second image forming portions and a second intermediate transfer medium to which a toner image formed by the plural second image forming portions is primarily transferred, a sheet transport portion that transports a sheet to a secondary transfer position at which each of the toner image formed on the first intermediate transfer medium of the first image forming unit and the toner image formed on the second intermediate transfer medium of the second image forming unit is secondarily transferred, and a processor configured to, in performing registration between a position of an image printed on the sheet by the first image forming unit and a position of an image printed on the sheet by the second image forming unit, cause each of one first image forming portion selected from the plural first image forming portions of the first image forming unit and one second image forming portion selected from the plural second image forming portions of the second image forming unit to form the image at the same position on the sheet, and reduce a misregistration amount by partially changing a drawing cycle of the image in any one of the first image forming unit or the second image forming unit in accordance with a relative misregistration amount between the two formed images.