Thermal Printer Velocity Control for Bar Code Print Ratio
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Solution Overview
Problem
Conventional portable thermal printers face issues with printing misalignment and varying printing thickness due to changes in print ratio, leading to unclear or missing prints, especially when printing bar codes, as they struggle to maintain high print quality and velocity.
Innovation Solution
A thermal printing apparatus with a thermal head that analyzes print layouts for bar codes, calculates and adjusts printing velocity based on print ratios, and divides strobe signals across heating elements to maintain consistent printing quality and velocity, preventing misalignment and tracing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high current is supplied to simultaneously apply strobe signals to multiple heating elements for high print ratio, then printing velocity is improved, but battery power is depleted quickly and voltage drops causing unclear printing
Solution Approach 1:
The patent divides the heating elements into multiple groups (first group and second group) and applies strobe signals to them sequentially at different timings. This segmentation allows the system to maintain high print ratio without requiring simultaneous high current to all heating elements, thus reducing peak power consumption and preventing voltage drop while maintaining printing velocity.
2Loss of energy
If strobe signals are sequentially applied to divided blocks to reduce power consumption, then energy loss is reduced, but printing misalignment and varied printing thickness occur
Solution Approach 1:
The patent dynamically adjusts the paper carrying velocity based on the print ratio. When the print ratio is high (more heating elements active), the paper carrying velocity is reduced to allow sequential strobe signals to produce aligned printing. When print ratio is low, velocity can be increased. This dynamic velocity adjustment compensates for the sequential signal application and maintains printing precision while enabling power-saving sequential operation.
3Manufacturing precision
If paper carrying velocity is changed in one step to match print ratio, then printing precision is improved, but the platen roller cannot respond due to moment of inertia
Solution Approach 1:
The system implements dynamic velocity control that adapts to print ratio requirements. The platen roller's rotational speed is adjusted according to the calculated print ratio, allowing the mechanical system to respond appropriately to different printing demands while accounting for its moment of inertia.
Solution Approach 2:
The patent calculates the print ratio based on print data and uses this information to control the paper carrying velocity. This feedback mechanism ensures that the velocity is appropriately adjusted according to the actual printing requirements, maintaining precision while managing the mechanical response limitations.
4Manufacturing precision
If minimum velocity is maintained to prevent misalignment, then printing precision is improved, but processing time increases
Solution Approach 1:
Rather than maintaining minimum velocity constantly, the system dynamically adjusts velocity based on print ratio. When print ratio is high, velocity is reduced to ensure alignment. When print ratio is low, velocity can be increased to reduce processing time. This dynamic adjustment optimizes both precision and speed.
Solution Approach 2:
The patent changes the paper carrying velocity parameter according to the print ratio. By adjusting this parameter dynamically rather than keeping it constant, the system achieves good printing alignment when needed while minimizing processing time when high precision is less critical.
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
The solution ensures correct and clear printing of bar codes without reducing printing velocity, preventing reading errors and maintaining high print quality even with changes in print ratio or number of strobe blocks, thus addressing the challenges of misalignment and varying thickness.
Implementation Method 1
the thermal printer heats heating elements corresponding to printing parts among a plurality of heating elements to enable printing of various kinds of information line by line
Data Source
AI summary
A printing apparatus includes a thermal head in which a plurality of heating elements are provided in a width direction of paper, an analyzing unit which analyzes whether an input print layout contains any bar code, a calculating unit which calculates a print ratio of a bar code portion in the paper for each line of the print layout in the case where the analyzing unit analyzes that at least the print layout contains a bar code, a setting unit which sets a printing velocity corresponding to the print ratio for one line in the bar code portion calculated by the calculating unit in the case where the analyzing unit analyzes that the print layout contains the bar code and a changing unit which changes a velocity at which the thermal head performs printing on the paper for one line to the printing velocity set by the setting unit.