Color Misregistration Correction Using Multi-Sensor Temperature Detection
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Solution Overview
Problem
In electrophotographic color image forming apparatuses, the deformation and positional changes of optical components due to heat from a deflector cause laser beam misregistration, leading to color misregistration issues, as temperature sensors placed outside the unit housing struggle to accurately detect the temperature of the optical system, resulting in poor prediction accuracy of color misregistration.
Innovation Solution
An image forming apparatus with multiple temperature detection units, including a first detection unit on the exposure device circuit board, a second detection unit for environmental temperature, and a third detection unit positioned farther away, along with a detection unit for patch images, allows for accurate detection and correction of color misregistration by adjusting the image write start timing based on temperature differences and detected color misregistration amounts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the temperature sensor is provided outside the unit housing to suppress air flow influence, then the temperature measurement is less affected by air flow, but the distance between the optical system and the temperature sensor becomes long so that the detected temperature does not sufficiently follow the temperature rise of the optical system
Solution Approach 1:
The temperature detection function is divided into multiple sensors positioned at different locations (inside and outside the housing) to capture different temperature characteristics. The first temperature sensor inside the housing captures local heat effects while the second temperature sensor outside captures environmental temperature, and these measurements are combined to achieve both accuracy and air flow independence.
2Stability of the object's composition
If the temperature sensor is arranged in a center part of the unit housing to suppress air flow influence, then the variation amount in temperature is small, but the sensitivity to the temperature in controlling the position misregistration amount becomes high causing control error
Solution Approach 1:
Different temperature sensors are placed at different locations to detect different temperature characteristics. The first temperature sensor is positioned to detect local temperature changes near the heat source, while the second temperature sensor detects environmental temperature. This localized measurement approach allows the system to capture actual heat effects without being overly sensitive to ambient variations.
3Object-affected harmful factors
If the temperature sensor is provided outside the unit housing, then the influence of the air flow is no longer received, but the detected temperature does not sufficiently follow the temperature rise of the optical system
Solution Approach 1:
The patent combines measurements from two temperature sensors (one inside the housing near the optical system and one outside) to create a comprehensive temperature detection system. This merged approach allows the system to track the optical system's temperature rise while filtering out air flow influences through the external sensor's environmental temperature reading.
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 solution improves the prediction accuracy of color misregistration by accurately accounting for temperature variations and positional changes, enabling precise correction and reducing image misregistration errors.
Implementation Method 1
a first temperature detection unit provided on a circuit board of the exposure device, and configured to detect a first temperature of the exposure device
Implementation Method 2
a second temperature detection unit configured to detect a second temperature; a third temperature detection unit configured to detect a third temperature
Implementation Method 3
the deformation and changes in position and posture of optical components such as a lens and a mirror due to heat generated from a deflector
Data Source
AI summary
Prediction accuracy of a color misregistration amount in an image formation executed in an image forming apparatus is improved. The image forming apparatus comprises an optical box storing an optical system for irradiating a laser beam from a laser source to a photosensitive drum, a scanner temperature sensor provided near the optical box, and an environmental temperature sensor for detecting a surrounding temperature of the image forming apparatus, and a control section. When image formation is executed, the control section obtains a temperature Tscn detected by the scanner temperature sensor and a temperature Tenv detected by the environmental temperature sensor and calculates a prediction value of a position misregistration amount to the photoreceptor of the laser beam using the difference between Tscn and Tenv.