Printhead Spacing Compensation via Encoder Timing
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Solution Overview
Problem
Inkjet printing systems face image quality degradation due to variations in printhead-to-printhead spacing caused by temperature-induced expansion or contraction of the printhead support, leading to misalignment of nozzles and inaccurate ink drop placement.
Innovation Solution
A measurement system using encoders to determine changes in printhead spacing and a compensation module within the printer controller to adjust nozzle firing timing or redundancy, ensuring precise ink drop placement by applying timing offsets or generating signals to compensate for spacing variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple printheads are used to increase printing width and productivity, then printing efficiency is improved, but maintaining precise printhead-to-printhead alignment becomes more difficult due to thermal expansion and contraction
Solution Approach 1:
The system dynamically adjusts timing parameters (firing offsets) based on measured temperature changes and thermal expansion characteristics. The controller modifies the timing of ink drop ejection for each printhead according to its position and the measured thermal state, compensating for spacing variations without physical adjustment of the printheads.
Solution Approach 2:
Temperature sensors provide continuous feedback on the thermal state of the printhead support. The controller uses this feedback to calculate and apply appropriate timing offsets to each printhead, creating a closed-loop system that maintains alignment precision despite thermal fluctuations during operation.
2Manufacturing precision
If the printhead support structure is made more rigid to maintain spacing precision, then alignment stability is improved, but the system becomes more sensitive to thermal expansion and contraction
Solution Approach 1:
The system replaces mechanical adjustment mechanisms with an electronic timing compensation system. Instead of physically adjusting printhead positions to account for thermal expansion, the system uses electronic signals to modify the firing timing of each printhead based on measured thermal conditions, eliminating the need for complex mechanical compensation structures.
3Manufacturing precision
If temperature control of the printhead support is implemented to prevent expansion and contraction, then spacing stability is improved, but energy consumption increases
Solution Approach 1:
The system changes the operational parameters (timing offsets) of the printheads based on measured temperature conditions rather than attempting to maintain constant temperature. This approach accepts thermal variations but compensates for their effects through parameter adjustment, avoiding the continuous energy consumption required for active temperature control.
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 effectively reduces or eliminates image quality artifacts by maintaining precise printhead alignment, even with temperature-induced changes, thereby ensuring high-resolution printing quality.
Implementation Method 1
a) determining a distance d between two locations on the printhead support using a measurement system including an encoder
Implementation Method 2
Changes in temperature of the printhead support 102 may result in expansion or contraction of the printhead support 102
Data Source
Figure 1a~1b
Figure 2~4
Figure 5~6
AI summary
According toone example, there is provided asystem for compensating for changes in printhead-to-printhead spacing in a printing system having multiple printheads mountable on a printhead support. The system comprises a measurement system to determine a change in printhead-to-printhead spacing between different ones of mounted printheads, andaprocessor to determine compensation to be applied to the printing system to compensate for the determined change in printhead-to-printhead spacing. [FIGURE 2]