Ink Jet Recording Apparatus Negative Pressure Control
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Solution Overview
Problem
Conventional ink jet recording apparatuses experience defective ink ejection due to high viscosity ink and nozzle clogging, particularly when the recording head is heated and then cooled, leading to irregular ejections upon reactivation.
Innovation Solution
A control method for an ink jet recording apparatus that maintains negative pressure in the ink storage part after turning off the heating of the recording head, preventing the pressure from reaching a level that causes communication between the inside and outside, thereby preventing irregular ejections by adjusting the negative pressure control after the heating part is turned off and allowing the temperature to lower.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the recording head is heated to reduce ink viscosity for satisfactory ejection, then the ink ejection is improved, but when the heating is turned off and the temperature lowers, the negative pressure in the ink storage part becomes too large causing defective ejection
Solution Approach 1:
The control unit maintains the negative pressure adjusting part in the ON state for a predetermined period after turning off the heating part. This preliminary action prevents the negative pressure from becoming too large during the cooling phase, thereby avoiding defective ejection when the apparatus is reactivated. The negative pressure is maintained at an appropriate level during the transition period before being allowed to increase naturally.
2Object-generated harmful factors
If the negative pressure in the ink storage part is increased to prevent ink leakage from the recording head, then ink leakage is prevented, but air enters the system causing irregular ejection
Solution Approach 1:
The control unit dynamically adjusts the negative pressure level in the ink storage part based on the operational state. During and after heating, the negative pressure is maintained at a moderate level (not too large) to prevent air from entering through the opening part. The negative pressure adjusting part is kept ON for a predetermined period after heating to ensure the pressure remains within the safe range, preventing both ink leakage and air intrusion.
3Loss of energy
If the heating part is turned off immediately when the apparatus is turned off, then energy consumption is reduced, but defective ejection occurs due to large negative pressure from temperature lowering
Solution Approach 1:
The control unit implements a preliminary action by maintaining the negative pressure adjusting part in the ON state for a predetermined period after turning off the heating part. This ensures that the negative pressure remains at an appropriate level during the cooling phase, preventing defective ejection. Only after this period elapses does the control unit turn off the negative pressure adjusting part, thereby reducing energy consumption while maintaining reliability.
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 method effectively prevents defective ink ejection by maintaining a stable negative pressure in the ink storage part, preventing air from entering and causing irregular ejections, ensuring consistent ink delivery upon reactivation.
Implementation Method 1
a heating part for heating the recording head
Implementation Method 2
a negative pressure adjusting part which adjusts a pressure in the inside of the ink storage part to be a negative pressure
Implementation Method 3
the temperature of the ink in the inside of the ink storage part is lowered and then the volume of the air in the inside of the ink storage part is contracted and thus the negative pressure in the inside of the ink storage part becomes large
Data Source
AI summary
A control method is provided for an ink jet recording apparatus 30 including a recording head 32 for ejecting ink to a medium 31, a heating means 46 for heating the recording head 32, an ink storage part 12 which reserves ink supplied to the recording head 32, and a negative pressure adjusting part 40 which adjusts a pressure in an inside of the ink storage part 12 to be a negative pressure. In the control method, when the ink jet recording apparatus 30 is to be turned off, heating of the recording head 32 by the heating part 46 is turned off but the negative pressure adjusting part 40 is left to be in an “ON” state so that the negative pressure in the inside of the ink storage part 12 is maintained and, after that, the negative pressure adjusting part 40 is turned off.