Dual-Sensor Heater Control for Image Quality
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Solution Overview
Problem
In image forming apparatuses, inappropriate temperature control of recording media leads to issues like cockling, ink blocking, and air blisters, due to uneven temperature distribution and erroneous heating detection, which deteriorate image quality and disrupt the conveyance process.
Innovation Solution
An image forming apparatus equipped with a heater, a first temperature sensor to measure the heater's temperature, a second temperature sensor to measure the region heated, and processing circuitry that controls the heater based on threshold comparisons to maintain optimal temperature settings, ensuring the heater operates only when necessary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the heater continues heating when a sheet is erroneously detected as being conveyed, then the sheet is excessively heated, but image quality deteriorates and conveyance abnormalities occur
Solution Approach 1:
The patent implements a feedback control mechanism where the detection result of the sheet conveyance state is fed back to the heater control unit. When the detection unit erroneously detects a sheet as being conveyed, the feedback mechanism allows the heater to stop heating, preventing excessive heating damage while maintaining reliable temperature control. This resolves the contradiction by using the detection feedback to adjust heating based on actual conditions rather than continuing heating based on erroneous detection.
2Use of energy by moving object
If the heater temperature is not properly controlled, then energy consumption is reduced, but cockling and image quality deterioration occur
Solution Approach 1:
The patent applies dynamic temperature control where the heater operation is adjusted based on real-time detection of sheet conveyance state. The heater is dynamically turned on or off according to whether a sheet is actually present and being conveyed, rather than maintaining a fixed heating state. This dynamic adjustment ensures optimal temperature control for image quality while avoiding unnecessary energy consumption when no sheet is present.
3Device complexity
If the heater is controlled based on single temperature threshold, then control simplicity is maintained, but temperature distribution uniformity deteriorates
Solution Approach 1:
The patent implements different temperature thresholds for different heating stages or regions. The heater control unit uses a first temperature threshold for initiating heating and a second temperature threshold for stopping heating, creating different temperature control zones or stages. This local quality approach ensures uniform temperature distribution across the sheet while maintaining relatively simple control logic through threshold-based decision making.
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 prevents overheating and underheating, maintaining appropriate temperature control, thereby improving image quality and preventing conveyance abnormalities, ensuring consistent and reliable operation of the image forming apparatus.
Implementation Method 1
a heater (17) that heats a medium (50) on which an image is formed
Implementation Method 2
a first temperature sensor (32, 34, 36) that measures a temperature of the heater (17), and a second temperature sensor (38) that measures a temperature of a region heated by the heater (17)
Data Source
AI summary
An image forming apparatus includes a heater, a first temperature sensor, a second temperature sensor, and processing circuitry. The heater is configured to heat a medium on which an image is formed. The first temperature sensor is configured to measure a temperature of the heater. The second temperature sensor is configured to measure a temperature of a region heated by the heater. The processing circuitry is configured to control the temperature of the heater. The processing circuitry is configured to control the heater based on a comparison between a measured temperature of the first temperature sensor and a first threshold value, and a comparison between a measured temperature of the second temperature sensor and a second threshold value.