Thermal Head Drive Circuit Timing Offset for Uniform Temperature Gradient
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Solution Overview
Problem
Existing thermal head drive circuits result in discontinuous temperature gradients across thermal head substrates, leading to color irregularities in printed results due to sequential heat transfer from one thermal head to the next.
Innovation Solution
A thermal head drive circuit that applies varying time delays to print data bits supplied to thermal heads, with greater delays for higher-order odd-numbered heads and lesser delays for higher-order even-numbered heads, ensuring a flat temperature gradient across the substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If thermal head drive circuits output print data bits in sequential order from left to right, then the circuit operation is simple and straightforward, but discontinuous temperature gradients occur across thermal head substrates causing color irregularities
Solution Approach 1:
The patent applies preliminary action by pre-calculating and applying different time delays to different thermal heads before the printing process begins. The delay amounts are determined in advance based on the thermal head position (odd or even number) and are built into the drive circuit timing, allowing the system to proactively compensate for heat transfer effects before they cause temperature discontinuities.
Solution Approach 2:
The patent implements local quality by applying different time delay characteristics to different groups of thermal heads based on their specific positions. Odd-numbered thermal heads receive one delay pattern while even-numbered thermal heads receive a different delay pattern, allowing each local region to be optimized for its specific thermal characteristics rather than applying a uniform timing approach.
2Device complexity
If uniform time delays are applied to all thermal heads, then the drive circuit timing is simple and uniform, but color irregularities occur due to heat transfer from sequentially activated thermal heads
Solution Approach 1:
The patent applies parameter changes by modifying the time delay parameter differently for different thermal heads. Instead of using a uniform time delay for all thermal heads, the system varies the delay amount based on the thermal head number (odd or even), thereby changing the timing parameter to compensate for the harmful heat transfer effect and eliminate color irregularities.
Solution Approach 2:
The patent implements local quality by applying different time delay characteristics to different groups of thermal heads based on their specific positions. Odd-numbered thermal heads receive one delay pattern while even-numbered thermal heads receive a different delay pattern, allowing each local region to be optimized for its specific thermal characteristics rather than applying a uniform timing approach.
3Productivity
If thermal heads are activated in sequential order, then the printing process follows a simple linear progression, but temperature distribution becomes discontinuous at substrate boundaries
Solution Approach 1:
The patent applies preliminary action by pre-calculating and applying different time delays to different thermal heads before the printing process begins. The delay amounts are determined in advance based on the thermal head position (odd or even number) and are built into the drive circuit timing, allowing the system to proactively compensate for heat transfer effects before they cause temperature discontinuities.
Solution Approach 2:
The patent applies parameter changes by modifying the time delay parameter differently for different thermal heads. Instead of using a uniform time delay for all thermal heads, the system varies the delay amount based on the thermal head number (odd or even), thereby changing the timing parameter to compensate for the harmful heat transfer effect and eliminate color irregularities.
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 produces a continuous temperature gradient across the thermal head substrate, significantly reducing color irregularities in printed results by offsetting temperature gradients from odd and even-numbered thermal heads.
Implementation Method 1
linearly-arranged thermal heads are used that generate heat upon application of electric current from corresponding drive circuits
Implementation Method 2
heat is transferred across the corresponding thermal head substrate 14 from the thermal head 121 that first generates heat toward the thermal head 122N that last generates heat
Data Source
AI summary
A thermal head drive circuit drives M number of thermal heads for printing one line and includes a delay unit that applies different time delays to M bits of print data to be supplied to the corresponding M thermal heads. The higher order the odd number thermal heads of the M thermal heads are, the greater are the time delays applied to the corresponding bits of the print data, while the higher order the even number thermal heads of the M thermal heads are, the less are the time delays applied to the corresponding bits of the print data.