Optical Detection for Print Media Boundary Positioning
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Solution Overview
Problem
Existing image forming apparatuses face challenges in accurately detecting print media, particularly when the transmittance of the base sheet region is low, making it difficult to distinguish the boundary between the base sheet and label regions, which affects the detection of print media with varying transmittances.
Innovation Solution
The implementation of a medium carrying device with a detection mechanism using light emitting and receiving parts to perform light amount measurements, allowing the control part to set specific light emission levels and threshold values for accurate detection of the print medium's regions, enabling precise positioning and boundary detection between the base sheet and label regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Difficulty of detecting and measuring
If a light emitting part and light receiving part are used to detect the print medium, then detection capability is improved, but measurement precision deteriorates when the base sheet has low transmittance
Solution Approach 1:
The control part performs preliminary light amount measurements to determine the emitted light amount and threshold light amount before actual detection. By pre-setting the emitted light amount based on measurements taken when the first region is facing the detection part, and pre-determining the threshold based on measurements when the second region is facing the detection part, the system prepares optimal detection parameters in advance, enabling accurate boundary detection even with low transmittance base sheets
Solution Approach 2:
The system dynamically adjusts the emitted light amount parameter and threshold light amount parameter based on measurements. The control part sets the emitted light amount to a value determined from preliminary measurements, and sets the threshold to a value determined from preliminary measurements with the first emitted light amount. This parameter adaptation allows the detection system to optimize its sensitivity for different media conditions, resolving the contradiction between detection capability and measurement precision
2Area of stationary object
If the light emitting part emits high light amount, then detection range is improved, but detection accuracy deteriorates due to saturation
Solution Approach 1:
The control part uses feedback from preliminary light amount measurements to determine the optimal emitted light amount. By measuring the light receiving amount when the first region is facing the detection part and using this feedback to set the emitted light amount, the system automatically adjusts to prevent saturation while maintaining adequate detection range. The threshold is also set based on feedback from preliminary measurements, ensuring accurate boundary detection
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 enables high-accuracy detection of print media, even with low transmittance base sheets, allowing for reliable image formation and improved detection of media with varying transmittances.
Implementation Method 1
a light emitting part and a light receiving part arranged sandwiching the carrying path, and that detects the print medium carried on the carrying path according to a light amount of a light that is received by the light receiving part, the light being emitted from the light emitting part and coming through the carrying path
Data Source
AI summary
A medium carrying device includes a carrying part that carries a continuous print medium, a detection part that includes a light emitting part and a light receiving part arranged sandwiching a carrying path, and that detects the print medium carried on the carrying path according to a light amount that is received by the light receiving part, and a control part that controls operations of the carrying part and the detection part, wherein the control part sets a first emitted light amount of the emitted light of the light emitting part used in image formation to the print medium by performing a light amount measurement using the light emitting part and the light receiving part in a state where the print medium is carried to a first position, and sets a threshold light amount that is used in detecting a boundary position between the first region and the second region by the detection part through performing another light amount measurement by obtaining a receiving light amount of the light receiving part with the first emitted light amount and by determining the threshold light amount based on the receiving light amount in a state where the print medium is carried from the first position to another second position.