Tension Applying Unit for Sheet Transport Detection
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Solution Overview
Problem
Ink jet printers face challenges in accurately detecting the transport amount of sheets due to deformation caused by strain when using a motion sensor with a varying distance from the sheet, leading to potential inaccuracies in transport amount detection.
Innovation Solution
A target transporting device is designed with a tension applying unit that maintains a constant distance between the transport amount detecting unit and the sheet by applying a tension force via the sheet's own weight, ensuring accurate detection even under strain conditions, and featuring a curved surface to enhance rigidity and prevent deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a motion sensor is provided in the vicinity of a roller pair that pinches and transports a sheet, then the transport amount can be detected, but the sheet may deform due to strain causing distance variation between the sensor and sheet, leading to detection inaccuracy
Solution Approach 1:
A tension applying unit is introduced as an intermediary component between the roller pair and the motion sensor. This unit applies tension to the sheet in the upstream direction, counteracting the strain caused by the pinching rollers and preventing sheet deformation, thereby maintaining a stable detection distance for accurate transport amount measurement
Solution Approach 2:
The tension force parameter is introduced to change the mechanical state of the sheet. By applying an appropriate tension force in the upstream direction, the sheet's physical state is adjusted to resist deformation caused by the pinching rollers, ensuring stable geometric parameters for accurate optical detection
2Force
If the tension applying unit supports the target while causing the upstream portion to hang down by gravity, then a tension force can be applied using the target's own weight, but the target may deform in the width direction
Solution Approach 1:
The tension applying unit features a curved surface that contacts the target. This curved geometry distributes the support force across a broader area and provides lateral stability, preventing the target from deforming in the width direction while still allowing it to hang down and generate the necessary tension force through gravity
3Ease of operation
If the transport amount detecting unit is disposed upstream of the transporting unit, then it can detect transport amount without contact, but the distance to the target varies when strain is generated, compromising detection accuracy
Solution Approach 1:
The tension applying unit serves as a mediator that stabilizes the target's position and shape in the detection zone. By applying upstream tension, it compensates for strain-induced variations in the distance between the non-contact motion sensor and the target, ensuring accurate transport amount detection while maintaining ease of non-contact operation
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 allows for precise detection of the transport amount by maintaining a consistent distance and suppressing deformation, ensuring accurate measurement regardless of sheet thickness or strain.
Implementation Method 1
it is preferable for the tension applying unit to support the target while causing a portion of the target on the upstream side of the tension applying unit to hang down by gravity
Data Source
AI summary
A target transporting device includes a pair of transport rollers that applies a transport force to a continuous-form sheet toward a downstream side from an upstream side while pinching the continuous-form sheet; a guide member that applies a tension force to the continuous-form sheet being pinched by the pair of transport rollers toward the upstream side in a transport direction of the continuous-form sheet; and an image capturing unit that is disposed at a location upstream of the pair of transport rollers on a transport path of the continuous-form sheet so as to detect a transport amount of the continuous-form sheet to which the tension force is being applied by the guide member without contact.