Liquid Ejecting Head Drive Unit With Reversible Water Cooling
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Solution Overview
Problem
In high-speed line head printing, the increased nozzle density in the sheet width direction leads to larger apparatus size, longer signal transmission distances, and higher inductance issues, affecting ejection stability and cooling efficiency.
Innovation Solution
A drive unit with a drive circuit, thermal conductive material, water cooling mechanism, and a pump that switches liquid flow direction, combined with a liquid ejecting head unit and a collective board, to enhance thermal management and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If heads are arranged densely in sheet width direction to increase nozzle density, then image definition is improved, but apparatus size increases and signal transmission distance increases
Solution Approach 1:
The drive circuit is repositioned from a conventional distant location to the back surface of the head in the thickness direction, changing the spatial arrangement from planar to three-dimensional. This reduces the signal transmission distance along the sheet width direction while maintaining dense head arrangement for high image definition.
2Reliability
If drive circuit is disposed just above head to reduce signal transmission distance, then ejection stability is improved, but cooling efficiency deteriorates
Solution Approach 1:
A heat dissipation member is introduced as an intermediary component between the drive circuit and the cooling mechanism. This heat dissipation member enhances thermal conduction from the drive circuit to the cooling mechanism, allowing effective cooling while maintaining the drive circuit's optimal position for stable ejection.
Solution Approach 2:
The cooling mechanism is enhanced by introducing a water cooling system with a pump, replacing or supplementing passive cooling methods. This active cooling system efficiently removes heat from the drive circuit, enabling stable operation without compromising ejection stability.
3Temperature
If water cooling mechanism is added to improve cooling efficiency, then thermal management is improved, but device complexity increases
Solution Approach 1:
The cooling mechanism is integrated with the drive circuit assembly by positioning the heat dissipation member and water cooling components directly adjacent to the drive circuit on the head back surface. This merging of functions reduces overall device complexity compared to separate cooling systems, while maintaining efficient thermal management.
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
Improves ejection stability and cooling efficiency, addressing the challenges of high-speed printing with dense nozzle arrangements.
Implementation Method 1
a thermal conductive material that is in contact with the drive circuit on an opposite side in relation to the drive board
Implementation Method 2
a pump that causes liquid in the water cooling mechanism to flow
Data Source
AI summary
A drive unit is configured to generate a drive signal for driving a liquid ejecting head unit. The drive unit includes a drive board on which a drive circuit configured to generate the drive signal is mounted; a thermal conductive material that is in contact with the drive circuit on an opposite side in relation to the drive board; a water cooling mechanism that is in contact with the thermal conductive material on an opposite side in relation to the drive circuit; a pump that causes liquid in the water cooling mechanism to flow; and a control circuit that controls operation of the pump. The control circuit switches a direction in which the pump causes the liquid to flow between a forward direction and a reverse direction that is an opposite of the forward direction.