Transfer Unit Gear Position Detection for Belt Contamination Control
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Solution Overview
Problem
Conventional tandem color image forming apparatuses face issues with inconsistent transfer roller positioning, leading to contamination of the transfer belt and increased driving torque, especially in monochrome mode where unnecessary contact with cyan, magenta, and yellow image carriers occurs.
Innovation Solution
A transfer unit with a pinion gear mechanism, light shielding plate, and gear position detection sensor that accurately controls the movement of transfer rollers between contact and separation positions, using a light shielding plate with slits to detect rotation and a photointerrupter sensor to set reference positions, allowing precise positioning and mode switching between color, monochrome, and standby modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If transfer rollers are kept in contact with the transfer belt in monochrome mode, then the structure is simple, but the transfer belt becomes contaminated and driving torque increases
Solution Approach 1:
The transfer rollers are designed to dynamically switch between contact and separation states from the transfer belt. In monochrome mode, the yellow, magenta, and cyan transfer rollers separate from the transfer belt while the black transfer roller maintains contact, allowing the system to adapt to different operating modes and prevent contamination.
Solution Approach 2:
The transfer rollers are controlled independently through separate drive mechanisms. Each transfer roller can be individually positioned in contact or separation states, allowing selective engagement with the transfer belt based on the imaging mode (monochrome or color).
2Device complexity
If transfer rollers are kept in contact with the transfer belt in monochrome mode, then the structure is simple, but driving torque is unnecessarily increased
Solution Approach 1:
The system dynamically adjusts the contact state of transfer rollers based on operational requirements. In monochrome mode, only the black transfer roller contacts the transfer belt, minimizing friction and driving torque requirements while maintaining full functionality.
3Device complexity
If the transfer roller stops at the contact position or separation position during mode switching, then the positioning is simplified, but the stop position varies affecting transfer performance
Solution Approach 1:
A sensor detects the position of the transfer roller and provides feedback to the control system. Based on this feedback, the control system adjusts the drive mechanism to ensure the transfer roller stops at the precise contact position, maintaining consistent transfer performance across mode switches.
4Measurement precision
If a sensor is used to detect the rotation position of the cam, then the transfer roller positioning is accurate, but the device complexity increases
Solution Approach 1:
A light-shielding plate attached to the drive gear serves as an intermediary element for position detection. The plate modulates light from a light source, creating detectable signals that indicate the rotational position of the drive gear and consequently the position of the transfer roller, enabling accurate measurement without complex direct sensing.
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
Ensures accurate and reliable positioning of transfer rollers, preventing belt contamination and reducing unnecessary torque, thereby enhancing transfer performance and extending belt life by allowing frequent mode switching and stable belt operation.
Implementation Method 1
the light shielding plate... includes a pulse portion in which a plurality of slits are formed at uniform intervals, and at least one of a light shielding portion and a light transmitting portion formed adjacent to the pulse portion. A rotation amount of the gear is detected based on the number of the slits of the pulse portion that has passed the detection portion, and a reference position of the gear is detected based on timing when an edge of the light shielding portion passes the detection portion so as to block the optical path of the detection portion
Data Source
AI summary
A transfer unit includes a transfer belt, transfer rollers, support members, moving members, a pinion gear, a sensor, and a light shielding plate that blocks or opens an optical path of the detection portion by rotation of a gear transmitting the drive force to the pinion gear. The light shielding plate includes a pulse portion in which a plurality of slits are formed, and at least one of a light shielding portion and a light transmitting portion formed adjacent to the pulse portion. A rotation amount of the gear is detected based on the number of the slits of the pulse portion that has passed the detection portion, and a reference position of the gear is detected based on timing when an edge of the light shielding portion blocks the detection portion or timing when an edge of the light transmitting portion opens the optical path of the detection portion.