Color Misregistration Correction in Image Forming Apparatus
Solution Overview
Problem
Conventional color image forming apparatuses using optical sensors for color misregistration correction face usability issues due to the time and effort required for cleaning toner images, leading to reduced apparatus usability.
Innovation Solution
A color image forming apparatus with a pre-exposure unit, power supply unit, detection unit, color misregistration correction control unit, and light amount control unit, which forms and detects electrostatic latent images for color misregistration correction, allowing for reduced light emission and improved detection efficiency, thereby minimizing the need for extensive cleaning and enhancing usability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If toner images for detection are transferred from photosensitive drums onto an image bearing member for color misregistration correction, then color misregistration can be detected and corrected, but it takes time and effort for cleaning, resulting in reduced usability
Solution Approach 1:
The invention extracts the detection function from the toner image transfer process. Instead of transferring actual toner images onto the image bearing member for detection, the system detects color misregistration by monitoring the positional relationship between the photosensitive drums and laser scanners directly, eliminating the need for toner transfer and subsequent cleaning operations
Solution Approach 2:
The invention introduces an intermediary detection mechanism that uses optical sensors or markers on the photosensitive drums themselves to detect positional deviations, rather than relying on transferred toner images. This intermediary detection method allows for non-contact measurement and eliminates the harmful side effect of toner residue requiring cleaning
2Reliability
If toner images for detection are applied to photosensitive drums and image bearing member, then color misregistration correction can be performed, but cleaning time and effort increase
Solution Approach 1:
The system performs preliminary detection of color misregistration using optical markers or sensors positioned on the photosensitive drums before the toner transfer process. By detecting positional deviations in advance, the system can correct misregistration without requiring toner image transfer and subsequent cleaning, thus eliminating the time loss associated with cleaning operations
Solution Approach 2:
Instead of using actual toner images for detection, the invention creates a virtual copy or representation of the positional relationship through optical markers or sensor readings. This copying approach allows for detection without the physical presence of toner images, thereby eliminating the need for cleaning
3Productivity
If laser scanners and photosensitive drums are independently provided for each color image forming unit, then high speed printing is achieved, but positional relation between laser scanner and photosensitive drum differs for each color, producing color misregistration
Solution Approach 1:
The invention implements a feedback control system that continuously monitors the positional relationship between laser scanners and photosensitive drums using optical sensors or markers. The detected positional deviations are fed back to the control unit, which adjusts the scanning positions or drum rotation phases to maintain precise alignment across all color channels, thereby correcting color misregistration while preserving high-speed printing capability
Solution Approach 2:
The system dynamically adjusts the operational parameters of laser scanners and photosensitive drums based on real-time detection results. By making dynamic corrections to scanning speeds, positioning, or synchronization timing, the system compensates for variations in positional relationships between independently provided components, maintaining manufacturing precision despite independent operation
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
The solution effectively reduces color misregistration and improves the usability of the image forming apparatus by streamlining the detection and correction process, reducing the time and effort needed for cleaning and maintaining the apparatus.
Implementation Method 1
a light amount control unit configured to, when the electrostatic latent image for color misregistration correction passes through a position facing the pre-exposure unit and before the electrostatic latent image for color misregistration correction passes through the position facing the charging unit, at least decrease the light emission amount of the pre-exposure unit
Implementation Method 2
a charging unit configured to charge the photosensitive member
Implementation Method 3
a light irradiation unit configured to perform light irradiation to form an electrostatic latent image on the photosensitive member
Implementation Method 4
a development unit configured to apply toner to the electrostatic latent image to form a toner image on the photosensitive member
Data Source
AI summary
An image forming apparatus includes a process unit arranged in the vicinity of the circumference of each photosensitive member and the process unit is configured to act on the photosensitive member in forming a toner image thereon. The image forming apparatus detects a time period since a laser beam emission unit emits a laser beam to the photosensitive member to form an electrostatic latent image for detection until the formed electrostatic latent image for detection or a toner image based on the electrostatic latent image for detection reaches the process unit, and performs color misregistration correction control based on the result of detection. In this case, a control unit at least decreases the light amount of a pre-exposure LED when the electrostatic latent image for detection passes through a position facing the pre-exposure LED.