Photoconductor Speed Control for Color Misregistration
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Solution Overview
Problem
Color misregistration in tandem-type color image forming apparatuses is challenging due to differences in photoconductor diameters, leading to noticeable pitch fluctuations and increased costs in correcting eccentricity-related issues.
Innovation Solution
A color image forming apparatus with a plurality of drum-type photoconductors of varying diameters, driven at speeds corresponding to their diameters, and a correction signal system that outputs speed correction signals to adjust the driving speed of each photoconductor to match the rotational cycle, thereby correcting periodic pitch fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If photoconductors with different diameters are used to extend service life and increase print speed, then productivity is improved, but manufacturing precision deteriorates due to color misregistration
Solution Approach 1:
The patent applies parameter changes by adjusting the rotational speeds of photoconductors with different diameters. Specifically, the black photoconductor rotates at a different speed than color photoconductors to compensate for the mismatch caused by diameter differences. This speed adjustment ensures that the peripheral speeds are properly coordinated, eliminating color misregistration while allowing the use of different photoconductor diameters for improved productivity
Solution Approach 2:
The patent implements dynamics by making the rotational speeds of photoconductors adjustable and variable. The control unit dynamically adjusts the rotation speeds based on the specific diameter of each photoconductor, allowing the system to adapt to different configurations and maintain precise color registration despite using photoconductors with varying sizes for extended service life
2Duration of action of stationary object
If photoconductors with different diameters are used, then service life is extended, but device complexity increases due to speed coordination requirements
Solution Approach 1:
The patent applies universality by using a single control unit that manages the rotation speeds of all photoconductors with different diameters. This control unit serves multiple functions: it coordinates the speeds of color photoconductors, adjusts the speed of the black photoconductor, and ensures proper synchronization across the entire system, thereby managing complexity through a unified control mechanism
Solution Approach 2:
The patent implements feedback by using a sensor to detect the rotational phase of each photoconductor and providing this information to the control unit. The control unit uses this feedback to continuously adjust and coordinate the rotation speeds, ensuring that photoconductors with different diameters remain properly synchronized throughout operation, thus managing system complexity through active monitoring and adjustment
3Duration of action of stationary object
If black photoconductor diameter is increased to prolong service life, then duration of action is improved, but color misregistration increases due to different rotational cycles
Solution Approach 1:
The patent applies parameter changes by adjusting the rotational speed of the black photoconductor to compensate for its larger diameter. The control unit calculates the appropriate speed adjustment based on the diameter difference and ensures that the black photoconductor rotates at a speed that maintains proper synchronization with color photoconductors, thereby preventing color misregistration despite the diameter mismatch
Solution Approach 2:
The patent uses a sensor to detect the rotational phase of the black photoconductor and creates a feedback signal that is processed by the control unit. This copying of phase information allows the system to understand the rotational state of the black photoconductor and make necessary speed adjustments to maintain proper coordination with color photoconductors
Data Source
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AI summary
A color image forming apparatus including: a plurality of drum-type photoconductors for forming an image in a different color on each peripheral surface and the photoconductors having at least two different diameters; a plurality of driving sections for driving each photoconductor at a driving speed in accordance with the diameter so that each photoconductor rotates at a predetermined peripheral speed; a correction signal output section for outputting a speed correction signal to correct a periodic pitch fluctuation included in each formed image; and a drive control section for controlling the driving section to correct the driving speed of each photoconductor by the speed correction signal, wherein the speed correction signal is a signal having the same cycle as a rotational cycle of each photoconductor.