Ink Ribbon Spool Diameter Calculation for Skew Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional printing apparatuses face issues with detecting ink ribbon spool diameter accurately, leading to degraded detection accuracy due to backlash and skew, especially when the ink ribbon length is minimized, causing color deviations and requiring separate winding operations to detect empty marks.
Innovation Solution
A printing apparatus with a thermal head, ink ribbon transport mechanism, sensor for detecting empty marks, and rotation amount detection means to calculate spool diameter during printing, allowing for controlled winding and rewinding to prevent skew and optimize ink ribbon usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the ink ribbon length is minimized to reduce the transport amount during printing operation, then the productivity is improved, but the detection accuracy of empty mark deteriorates because the empty mark cannot be detected during printing operation
Solution Approach 1:
The system performs preliminary winding of the ink ribbon to the wind-up spool before printing operation starts. This preliminary action ensures that the empty mark is positioned in a detectable location prior to printing, allowing accurate detection without interrupting or extending the printing operation itself.
2Measurement precision
If the spool diameter is calculated using rotation amount detected during printing operation, then the measurement precision is improved, but the reliability deteriorates due to backlash and unsteady rotation
Solution Approach 1:
The system calculates the spool diameter using rotation amount detected during the preliminary winding operation before printing starts. This preliminary measurement is taken when the spool rotation is steady and controlled, avoiding the backlash and instability that occur during printing operation, thereby ensuring both accurate and reliable diameter detection.
3Measurement precision
If separate winding operation is performed to detect empty mark, then the measurement precision is improved, but the device complexity increases and printing quality deteriorates due to skew
Solution Approach 1:
The system merges the empty mark detection function with the existing ink ribbon transport and winding mechanism. By utilizing the preliminary winding operation that is already part of the printing process, the system detects the empty mark without requiring a separate, independent winding operation, thereby avoiding additional complexity and preventing ink ribbon skew.
4Measurement precision
If the ink ribbon is wound excessively to detect empty mark, then the measurement precision is improved, but the loss of substance increases due to unnecessary transport
Solution Approach 1:
The system performs a controlled preliminary winding operation that winds the ink ribbon only to the extent necessary to position the empty mark in a detectable location. This preliminary action is carefully controlled to avoid excessive winding, thereby minimizing unnecessary ink ribbon consumption while still enabling accurate empty mark 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 enhances printing quality by reducing unnecessary ink ribbon transport, preventing skew, and accurately detecting empty marks, thereby maintaining high printing quality and minimizing color deviations.
Implementation Method 1
performing printing processing on a recording medium with a thermal head via an ink ribbon
Data Source
AI summary
To provide a printing apparatus with high printing quality that reduces a transport amount of an ink ribbon except printing operation and that suppresses skew of the ink ribbon, diameters of spools 43, 44 are calculated from rotation amounts of the supply spool 43 and wind-up spool 44 corresponding to a printing length in a sub-scanning direction of the printing data during driving of a thermal head 40, a value of the calculated diameter is compared with a value of a beforehand set diameter, it is thereby determined whether or not an ink ribbon 41 is near empty, and when the ink ribbon is not near empty, the ribbon 41 is wound around the spool 44 up to a printing end position in which a rear end of a used portion of the ribbon 41 passes through a peeling member 28, while when the ink ribbon is near empty, the ribbon 41 is wound around the spool 44 until an empty mark EMP_M arrives at a position detectable by a sensor Se2, and then is rewound around the spool 43 until a front end of an unused portion of the ribbon 41 arrives at a feeding position.