Printer Roll Sheet Detection via Roller Rotation Feedback
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Solution Overview
Problem
Conventional printers face challenges in automatically determining whether a roll sheet or a cut sheet is loaded, leading to incorrect operation mode settings, especially when dealing with varying sheet sizes and formats, and require additional sensors and motors, increasing costs and reducing performance.
Innovation Solution
A recording apparatus with optical reflective sensors and conveyance rollers that detect sheet presence and position, using a control unit to determine the type of sheet based on sensor inputs and motor operations, allowing for automatic mode selection without the need for separate sensors and motor separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If a sensor on the downstream side of the conveying rollers and a motor for automatically separating the conveying rollers are added to automatically distinguish between roll sheet and cut sheet, then the automatic sheet type detection capability is improved, but the device complexity and cost increase
Solution Approach 1:
The system uses the existing conveyance rollers to perform self-detection by analyzing the difference between commanded rotation amount and actual rotation amount. The conveyance rollers themselves generate the detection signal through their rotation behavior when encountering different sheet types, eliminating the need for separate detection sensors and motors.
Solution Approach 2:
The patent replaces the mechanical detection system (separate sensors and motors) with a control-based detection method that uses the existing conveyance mechanism. The detection is achieved through electrical control and signal processing of the roller rotation data rather than additional mechanical components.
2Device complexity
If the conveyance rollers are kept together during roll sheet rewinding, then the device structure is simplified, but the nip pressure becomes excessive causing roller rotation and reducing sheet conveying performance
Solution Approach 1:
The patent makes the conveyance rollers dynamically adjustable by allowing them to be separated or brought together based on the detected sheet type. The separation amount is controlled according to the sheet thickness, enabling the system to adapt the roller configuration to different sheet types and maintain optimal conveying performance.
Solution Approach 2:
The system changes the physical parameter of the conveyance rollers (separation distance) based on the detected sheet type. When a roll sheet is detected, the rollers are separated by an amount corresponding to the sheet thickness, thereby changing the nip pressure to an appropriate level for that sheet type.
3Device complexity
If the sensor detects sheet presence based on simple presence/absence signals, then the detection system is simple, but the measurement precision is insufficient to accurately distinguish between roll sheet and cut sheet
Solution Approach 1:
The system implements feedback control by continuously monitoring the rotation amount of the conveyance rollers and comparing it with the commanded rotation amount. The difference between these values provides feedback information about the sheet type, enabling accurate distinction between roll sheets and cut sheets through iterative detection and adjustment.
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
Enables accurate and automatic determination of sheet type, reducing operational errors and costs by eliminating the need for additional sensors and motor separation, while supporting various sheet sizes and formats.
Implementation Method 1
optical reflective sensors and conveyance rollers that detect sheet presence and position
Data Source
Figure 1A~1B
Figure 2
Figure 3
AI summary
A recording apparatus includes a plurality of feeding units (12-15) each configured to feed a sheet, a conveyance unit (11) configured to convey the sheet to a recording unit (10), a first detection unit (18) provided on the upstream side of the recording unit (10) in the direction in which the sheet is conveyed and configured to detect the presence of the sheet, a driving control unit configured to control the driving of a motor for conveying the sheet in the form of a fed roll sheet, and a determination unit configured to determine which feeding unit (12-15) is feeding the sheet to the recording unit (10). If the first detection unit (18) detects the presence of the sheet, the driving control unit drives the motor in the direction for rewinding the roll sheet, and the determination unit executes the determination processing for the feeding unit based on an output value associated with the driving of the motor.