Toner Density Sensor Cleaning Brush With Retracted Contact Control
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Solution Overview
Problem
The challenge in electrophotographic image forming apparatuses is the variation in toner image density over time due to foreign matter adhering to the sensing surface of the sensor, necessitating effective cleaning to ensure accurate density correction.
Innovation Solution
Incorporation of a brush mechanism that moves in an intersecting direction with the sensor's light path for cleaning the sensing surface, controlled by a control portion to maintain brush contact during cleaning and retract when not in use, ensuring efficient and miniaturized sensor maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the brush is made long enough to contact the sensing surface for effective cleaning, then the cleaning effectiveness is improved, but the brush may contact the substrate or sensor package causing damage or interference
Solution Approach 1:
The brush is mounted on a movable support structure that allows it to move between a retracted position (where it does not contact the sensor package or substrate) and a cleaning position (where it contacts the sensing surface). This dynamic positioning enables the brush to perform effective cleaning when needed while avoiding contact with sensitive components during normal operation, thus resolving the contradiction between cleaning effectiveness and component protection
Solution Approach 2:
The support structure for the brush is divided into movable and fixed portions, allowing independent control of the brush's position relative to the sensor assembly. This segmentation enables precise control over when and where the brush contacts surfaces, permitting effective cleaning of the sensing surface while preventing contact with the substrate and sensor package
2Measurement precision
If the brush is positioned to contact the sensing surface for cleaning, then the density correction accuracy is improved, but the device complexity increases due to the need for precise positioning control
Solution Approach 1:
The movable support structure provides a simple yet effective mechanism for positioning the brush, using basic mechanical movement rather than complex control systems. The brush can be moved to the cleaning position only when density correction is being performed, and retracted otherwise, maintaining measurement precision while avoiding excessive device complexity
Solution Approach 2:
The brush is activated periodically or on-demand during specific operational phases (when density correction is performed) rather than continuously. This periodic action allows the brush to contact the sensing surface only when needed for cleaning during calibration, maintaining accuracy while simplifying the overall control mechanism by avoiding continuous engagement
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 effectively cleans the sensor surface, maintaining accurate toner density sensing while reducing apparatus size and noise, thereby enhancing the precision and efficiency of density correction.
Implementation Method 1
a sensor that applies light toward an outer circumferential surface of an image carrier and receives reflected light from the image carrier
Implementation Method 2
a brush that moves in an intersecting direction intersecting with the light applied by the sensor, and performs cleaning of a sensing surface of the sensor by use of the brush
Data Source
AI summary
An image forming apparatus includes a density sensing portion, a cleaning portion, and a control portion. The density sensing portion includes a substrate and a sensor package and outputs a sensing value related to a toner density of a toner image formed on an outer circumferential surface of an image carrier. The control portion performs control so that, when the cleaning portion performs cleaning of a sensing surface, a brush is moved to a cleaning position where the brush contacts the sensing surface. The control portion also performs control so that, when the cleaning portion does not perform the cleaning of the sensing surface, the brush is moved to a retracted position where the brush does not contact the sensor package and the substrate.