Image Forming Position Correction Across Variable Transfer Contact States
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Solution Overview
Problem
Existing image forming apparatuses face challenges in maintaining accurate image forming positions on both the front and back surfaces of printed sheets, particularly in tandem systems where contact states between photosensitive drums and a transfer belt vary between color and monochrome modes, leading to errors in correction values.
Innovation Solution
The apparatus includes a mechanical mechanism to control the contact state between photosensitive members and an intermediate transfer member, with separate contact states for color and black toner images, and a controller that adjusts image forming positions based on reading results from test images using CIS units, generating different data sets for each state to ensure accurate positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If three photosensitive drums other than black are separated from the transfer belt in monochrome mode, then abrasion is reduced and productivity is improved, but the tension of the transfer belt decreases and image forming position accuracy deteriorates
Solution Approach 1:
The patent applies dynamics by making the contact state between photosensitive drums and transfer belt variable rather than fixed. The mechanical mechanism dynamically adjusts the contact state based on printing mode: separated in monochrome mode for productivity, and in-touch in color mode for precision. This allows the system to optimize for different operational requirements.
Solution Approach 2:
The patent changes the physical parameter of contact state between photosensitive drums and transfer belt. By controlling the contact state to be either separated or in-touch based on printing mode, the system modifies the tension parameter of the transfer belt to achieve either reduced abrasion (separated) or maintained precision (in-touch).
2Manufacturing precision
If four photosensitive drums come in touch with the transfer belt in color mode, then image forming position accuracy is maintained, but abrasion increases and productivity deteriorates
Solution Approach 1:
The system dynamically adjusts the contact state based on the printing mode. In color mode, all four photosensitive drums are in-touch with the transfer belt to maintain image forming position accuracy. In monochrome mode, three drums are separated to reduce abrasion and improve productivity. This dynamic adjustment resolves the contradiction between precision and productivity.
Solution Approach 2:
The patent segments the photosensitive drums into different contact states based on printing mode. In monochrome mode, three color drums are separated from the transfer belt while the black drum remains in contact. This segmentation allows the system to maintain necessary contact for precision when needed while reducing unnecessary contact to improve productivity.
3Measurement precision
If correction values are generated using a chart printed in monochrome mode, then measurement precision is improved, but image forming position accuracy deteriorates in color mode due to different contact states
Solution Approach 1:
The patent applies local quality by generating separate correction values for different printing modes (color and monochrome). Instead of using a single set of correction values, the system creates mode-specific correction data that accounts for the different contact states. This ensures that correction values are optimized for the specific local condition (printing mode) in which they will be applied.
Solution Approach 2:
The system dynamically selects which correction values to apply based on the printing mode. The controller determines whether to use color mode correction values or monochrome mode correction values depending on the current printing operation. This dynamic selection ensures that the appropriate correction values are applied to maintain image forming position accuracy under different contact state conditions.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach ensures consistent and accurate image forming positions on both surfaces by adjusting image forming positions based on distinct data sets for different contact states, enhancing the precision of image placement.
Implementation Method 1
a reading unit that reads a test image on a sheet formed by the image forming unit
Data Source
AI summary
An image forming apparatus is configured to, based on a reading result of a test image, generate data that is used to adjust image forming positions of toner images to be formed by an image forming unit, control an image forming position of a first toner image to be formed by the image forming unit in a first contact state based on first data, the first toner image being transferred to a first sheet, and control an image forming position of a second toner image to be formed by the image forming unit in a second contact state based on second data that is different from the first data, the second toner image being transferred to a second sheet, wherein a type of the second sheet is the same type as the type of the first sheet.