Sensor Unit Positioning for Image Forming Apparatus
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Solution Overview
Problem
In image forming apparatuses, the positioning of potential sensors relative to electric boards is often compromised due to space constraints, leading to reduced measurement accuracy and potential image defects, especially when the sensor and board are separated and supported by a cantilever, affecting the precision of charge potential measurement on photosensitive members.
Innovation Solution
A sensor unit is detachably attached to a support frame, with a potential sensor positioned between the charging and developing units, and an electric board connected to the sensor unit, using a linking portion to maintain proximity to the photosensitive member, enhancing measurement accuracy by reducing the distance between the sensor and the photosensitive drum.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the electric board is disposed opposite to the potential sensor with respect to the photosensitive member to accommodate the larger area of the electric board, then the electric board can be properly positioned, but the distance between the potential sensor and the photosensitive member becomes long, deteriorating measurement accuracy
Solution Approach 1:
The patent repositions the electric board from being disposed opposite to the potential sensor (across the photosensitive member) to being disposed adjacent to the potential sensor in the same longitudinal direction. This spatial reconfiguration in a different dimensional arrangement allows both components to be positioned close to the photosensitive member without requiring the electric board to be placed across the drum, thereby maintaining short distances for both the sensor and the board while accommodating the board's larger area.
2Ease of repair
If the potential sensor and electric board are integrated into a replaceable unit, then replacement becomes easier, but the unit must be fixed to the side plate causing long distance and cantilever support, deteriorating positional accuracy
Solution Approach 1:
The patent changes the mounting location of the integrated sensor unit from the side plate to the longitudinal direction near the photosensitive member. By positioning the unit in this alternative spatial location, both the potential sensor and electric board can be mounted close to the photosensitive member without requiring long cantilever extensions from the side plate, thereby maintaining high positional accuracy while preserving the ease of replacement benefit.
Solution Approach 2:
The patent creates a modular sensor unit that combines the potential sensor and electric board as a replaceable assembly. This modular design allows the entire unit to be replaced as one component, simplifying maintenance while the redesigned mounting position ensures the unit can be fixed close to the photosensitive member without long support structures.
3Ease of operation
If the potential sensor is supported by a long cantilever from the side plate, then the sensor can be positioned in the apparatus, but the positional accuracy deteriorates causing image defects
Solution Approach 1:
The patent repositions the potential sensor from being supported by a long cantilever from the side plate to being positioned in the longitudinal direction close to the photosensitive member. This spatial reconfiguration places the sensor in a different location within the apparatus that allows direct mounting near the photosensitive member, eliminating the need for long cantilever support structures and thereby maintaining high positional accuracy for accurate charge potential measurement.
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 configuration improves the positional accuracy of the potential sensor, reducing image defects by ensuring precise measurement of the charge potential on the photosensitive member, facilitating easier assembly and maintenance, and enhancing the overall image forming process.
Implementation Method 1
a potential sensor configured to measure a potential of the photosensitive member
Data Source
AI summary
An image forming apparatus includes a rotatable photosensitive member, a charging unit, a developing unit, a support frame, and a sensor unit. The sensor unit is detachably attached to the support frame in a direction that intersects a rotation-axis direction of the photosensitive member and includes a potential sensor, a support portion, a fixing portion, an electric board, and a linking portion. The support portion supports the potential sensor at an area from the charging unit to the developing unit in a rotational direction of the photosensitive member. The fixing portion is fixed to the support frame at a position that faces an area from the developing unit to the charging unit in the rotational direction of the photosensitive member. The support portion is positioned with respect to the support frame at a position downstream of the support portion in an attachment direction of the sensor unit.