Label Printer Roller Torque Control for Peeling Stability
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Solution Overview
Problem
Existing label printers face challenges in stabilizing the tension of the base sheet, leading to peeling failures or poor paper feed accuracy due to reliance on frictional forces, which are difficult to control and stabilize.
Innovation Solution
A printing apparatus with a control unit that adjusts the voltage to the first driving unit based on label sheet transport velocity and acceleration to maintain a predetermined load torque, and performs feedback control on the second driving unit to maintain a predetermined velocity of the base sheet, using rollers with specific friction coefficients and surfaces to manage tension effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If frictional force is used to control base sheet tension, then the peeling mechanism can operate with simple structure, but the tension becomes unstable due to dependence on friction coefficient, wrap angle, and clamp force
Solution Approach 1:
The patent replaces the friction-based mechanical tension control system with an active control system that uses voltage adjustment to the first driving unit. The control unit calculates required voltage based on transport velocity and acceleration to maintain constant load torque, thereby stabilizing base sheet tension without relying on friction coefficients or clamp forces.
Solution Approach 2:
The patent changes the control parameter from passive frictional force to active voltage control. By adjusting the voltage applied to the first driving unit based on real-time transport velocity and acceleration measurements, the system dynamically maintains the load torque at a predetermined value, ensuring stable tension control.
2Ease of operation
If friction-based tension control is used, then the system is simpler to operate, but peeling failures occur due to reduction in tension
Solution Approach 1:
The patent implements a feedback control mechanism where the control unit continuously monitors transport velocity and acceleration, calculates the required voltage to maintain constant load torque, and adjusts the voltage to the first driving unit accordingly. This closed-loop feedback ensures reliable tension control and prevents peeling failures.
Solution Approach 2:
The patent replaces the unreliable friction-based tension control with an electrically-controlled system that actively maintains constant load torque through voltage adjustment, significantly improving peeling reliability while maintaining ease of operation through automated control.
3Device complexity
If friction-based tension control is used, then the system requires fewer control parameters, but poor paper feed accuracy occurs due to increase in tension
Solution Approach 1:
The patent changes the control approach from passive friction-based tension control to active voltage control with feedback. By adjusting voltage based on transport velocity and acceleration measurements, the system maintains constant load torque, ensuring accurate paper feed while managing control parameters efficiently through automated calculations.
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 approach stabilizes the tension between the rollers, preventing peeling failures and ensuring accurate paper feed by controlling the load torque and transport velocity, thereby improving the reliability of the label peeling process.
Implementation Method 1
The control unit controls an electric current value supplied to a peeling motor that causes the peeling roller to rotate, in a manner such that transportation force with which the peeling roller transports the base sheet is equal to or more than the minimum force necessary to peel the label and is also more than the maximum frictional force between the peeling roller and the base sheet
Implementation Method 2
the maximum frictional force described above and the maximum frictional force between the transport roller and the label sheet are set such that the maximum frictional force between the peeling roller and the base sheet is equal to or less than transport force of the peeling roller
Implementation Method 3
the control unit adjusts a voltage applied to the first driving unit on a basis of information about a transport velocity and a transport acceleration of the label sheet
Implementation Method 4
the control unit performs feedback control of a voltage applied to the second driving unit on a basis of information about a transport velocity of the base sheet
Data Source
AI summary
Included are a first roller disposed upstream of a peeling unit, a second roller disposed downstream of the peeling unit, a first motor configured to drive the first roller, a second motor configured to drive the second roller, and a control unit. The control unit includes a first-motor control unit configured to adjust a first voltage applied to the first motor on the basis of information about a transport velocity and a transport acceleration of the label sheet, such that a load torque of the first motor is a target torque, and also includes a second-motor control unit configured to perform feedback control of a second voltage applied to the second motor on the basis of information about a transport velocity of a base sheet, such that the transport velocity of the base sheet is a target transport velocity.