Sheet Conveyor Heater Sensor Placement for Fixing Quality
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In image forming apparatuses, the ends of the fixing belt and sheet may not be sufficiently heated during startup, leading to fixing failures and positional deviations in sheet conveyance, which can result in image defects and waste.
Innovation Solution
A sheet conveyor with a heating device that includes a heater, a first temperature sensor, and a second temperature sensor, with specific heat-distribution regions and sensor placements to ensure even heating and detection of the sheet, thereby preventing fixing failures and positional deviations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the heater starts heating from a cooled state, then the heating operation can begin, but the ends of the heater and fixing belt radiate heat to other members making temperature rise difficult
Solution Approach 1:
The patent divides the heating system into multiple independent heating zones along the fixing belt, with separate heaters or heating sections at different locations. Each zone can be controlled independently to ensure uniform temperature distribution, preventing heat loss to surrounding members and ensuring reliable fixing at all positions.
Solution Approach 2:
The fixing belt is divided into multiple sections with discrete heating elements positioned at specific intervals. This segmentation allows targeted heating of critical areas while reducing unnecessary heat radiation to non-critical members, improving overall thermal efficiency and fixing reliability.
2Productivity
If the fixing operation is performed when the temperature of the end of the fixing belt is not sufficiently increased, then the operation can proceed, but the end of the sheet is not sufficiently heated causing fixing failure
Solution Approach 1:
The system performs preliminary heating of the fixing belt and sheet before the actual fixing operation. Temperature sensors detect when the required temperature is achieved, and only then does the fixing operation commence, ensuring sufficient heating while maintaining operational efficiency.
Solution Approach 2:
Temperature sensors positioned at the ends of the fixing belt provide real-time feedback to the control system. When the temperature falls below the required threshold, the system automatically adjusts heating power or delays the fixing operation until adequate temperature is achieved, ensuring consistent fixing quality.
3Device complexity
If typical sheet width sensors or temperature detecting elements are used, then the device structure is simple, but positional deviation occurs in the conveyance orthogonal direction
Solution Approach 1:
The patent transitions from detecting sheet width at fixed positions to detecting the actual position of the sheet along its leading edge. By positioning sensors to detect the sheet's leading edge position in the conveyance direction, the system achieves precise positioning without increasing overall device complexity, as the same sensor type can be used in a different spatial configuration.
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 proposed solution ensures that the sheet is consistently and evenly heated, preventing fixing failures and positional deviations, thus improving the quality and reliability of the image forming process.
Implementation Method 1
a heater (22) including a base (30) and a heat generation portion (31)
Implementation Method 2
an end of the heater (22) and an end of a fixing belt (20) are likely to radiate heat to other members
Implementation Method 3
a first temperature sensor (25A) disposed at a first position in the conveyance orthogonal direction and facing the heater (22), a second temperature sensor (25B) disposed at a second position in the conveyance orthogonal direction and facing the heater (22)
Data Source
AI summary
A sheet conveyor includes a heating device to heat a recording medium and a recording medium sensor to detect the recording medium. The heating device includes a heater, a first temperature sensor to detect a temperature of the heater, and a second temperature sensor to detect the temperature of the heater. The heater has a first heat-distribution amount region on one side and a second heat-distribution amount region on the other side, in a conveyance orthogonal direction with respect to a reference position. The first heat-distribution amount region is greater in heat distribution amount than the second heat-distribution amount region. The first temperature sensor is disposed farther from the reference position than the second temperature sensor in the conveyance orthogonal direction. The first temperature sensor is disposed in the second heat-distribution amount region. The recording medium sensor is disposed in the first heat-distribution amount region.