Intermediate Transfer Layout for Color Registration in Tandem Printers
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Solution Overview
Problem
In image forming apparatuses using multiple image forming units, fluctuations in paper transport speed can cause misalignment of toner images at secondary transfer positions, leading to color misalignment in the final printed output.
Innovation Solution
The apparatus includes a configuration where the distance between the paper position adjusting roll and the secondary transfer positions is set longer than the maximum paper length for the largest paper size to prevent simultaneous speed fluctuations from being transmitted to both secondary transfer positions, and the distance between the fixing position and the first secondary transfer position is set longer than the maximum paper length to prevent speed fluctuations from affecting image fixation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the paper position adjusting roll is positioned close to the secondary transfer positions for efficient paper transport, then paper transport efficiency is improved, but speed fluctuations are simultaneously transmitted to both secondary transfer positions causing color misalignment
Solution Approach 1:
The patent segments the paper transport path by positioning the paper position adjusting roll only at the first secondary transfer position, while leaving the second secondary transfer position without a corresponding roll. This segmentation allows independent control of paper speed at each transfer position, preventing simultaneous speed fluctuations from affecting both positions and causing color misalignment.
Solution Approach 2:
The patent introduces an intermediary approach by using the distance between the paper position adjusting roll and the second secondary transfer position as a buffer zone. This distance, set longer than the maximum paper length, acts as a mediator that prevents speed fluctuations from the roll from being transmitted to the second secondary transfer position, thereby maintaining color alignment precision.
2Manufacturing precision
If the distance between the paper position adjusting roll and the second secondary transfer position is set longer than the maximum paper length to prevent speed fluctuation transmission, then color alignment precision is improved, but the apparatus complexity increases
Solution Approach 1:
The patent merges the functions of paper position adjustment and color alignment precision into a single structural configuration. By positioning the paper position adjusting roll only at the first secondary transfer position and using the distance to the second position as a design parameter, the system achieves both paper transport efficiency and color alignment precision without requiring separate complex control mechanisms at each position.
Solution Approach 2:
The patent applies parameter changes by setting the distance between the paper position adjusting roll and the second secondary transfer position to be longer than the maximum paper length. This parameter change fundamentally alters the transmission characteristics of speed fluctuations, preventing them from affecting the second secondary transfer position while maintaining a relatively simple apparatus structure.
3Manufacturing precision
If multiple image forming units are used to expand color gamut, then image quality is improved, but the complexity of coordinating paper transport and transfer operations increases
Solution Approach 1:
The patent segments the paper transport control by providing paper position adjusting rolls only at the first secondary transfer position, not at both positions. This segmentation simplifies the coordination complexity by reducing the number of synchronized control points, while still enabling high-quality image formation through multiple image forming units by maintaining proper paper positioning at the critical first transfer point.
Data Source
AI summary
An image forming apparatus includes: a first image forming unit that includes plural first image forming sections and a first intermediate transfer member on which a toner image formed by the plural first image forming sections is primarily transferred; a second image forming unit that is provided on a downstream side of the first image forming unit in a paper transport direction and includes plural second image forming sections and a second intermediate transfer member on which a toner image formed by the plural second image forming sections is primarily transferred; a first secondary transfer section that is provided corresponding to the first image forming unit and secondarily transfers the toner image formed on the first intermediate transfer member onto paper transported on a paper transport path; a second secondary transfer section that is provided corresponding to the second image forming unit and secondarily transfers the toner image formed on the second intermediate transfer member onto paper transported on a paper transport path; and a paper position adjusting roll that transports fed paper, at a predetermined timing, to a first secondary transfer position at which the first secondary transfer section performs secondary transfer, in which a distance between the paper position adjusting roll and a second secondary transfer position at which the second secondary transfer section performs the secondary transfer is longer than a maximum paper length that is a transport-direction length of paper having a largest paper size among sheets of paper having a probability of being used.