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 changes in sheet transport speed during the secondary transfer process.
Innovation Solution
An image forming system and method that adjusts the drawing cycle of images formed by one or both image forming units based on detected misregistration amounts, using test pattern images and reference positions to align images at the same position on the sheet.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If two image forming units are used to extend color gamut, then image quality and color range are improved, but partial misregistration occurs between images due to sheet transport speed changes
Solution Approach 1:
The system performs preliminary measurement of the sheet transport speed at the secondary transfer position before image formation. This advance detection allows the control unit to calculate appropriate drawing cycles for each image forming unit, ensuring that images will be formed at correct positions even when transport speed varies, thereby preventing misregistration while maintaining extended color gamut
Solution Approach 2:
The system dynamically adjusts the drawing cycle parameter of each image forming unit based on the measured sheet transport speed. By changing the drawing cycle according to actual transport conditions, the system compensates for speed variations and maintains precise image registration across multiple image forming units, resolving the contradiction between color gamut extension and registration accuracy
2Manufacturing precision
If sheet transport speed is adjusted to maintain constant speed, then image registration accuracy is improved, but device complexity increases due to speed control mechanisms
Solution Approach 1:
Instead of using complex mechanical speed control mechanisms to maintain constant transport speed, the system substitutes a measurement and calculation approach. The sheet transport speed is measured at the secondary transfer position, and the control unit calculates appropriate drawing cycles based on this measurement, eliminating the need for complex mechanical regulation while achieving precise image registration
Solution Approach 2:
The system implements feedback by measuring the actual sheet transport speed at the secondary transfer position and using this information to adjust the drawing cycles of the image forming units. This feedback mechanism allows the system to adapt to speed variations without requiring complex preventive control systems, reducing device complexity while maintaining registration accuracy
Data Source
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AI summary
An image forming system (10) includes a first image forming unit (30) including plural first image forming portions (32) and a first intermediate transfer medium (40) to which a toner image formed by the plural first image forming portions is primarily transferred, a second image forming unit (50) 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 (52) and a second intermediate transfer medium (60) to which a toner image formed by the plural second image forming portions is primarily transferred, a sheet transport portion (11) 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 (80) 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.