JPH0560845U - Print head for inkjet printer - Google Patents

Abstract

(57) [Summary] [Purpose] To improve printing speed, prevent air bubbles from being sucked from the nozzles, and prevent malfunction. [Structure] Ink cavities 3 and 5 are provided so as to be in contact with both sides of an ink ejecting mechanism 1, and ink supply from the ink ejecting nozzle 2 to the ink cavity after ink ejection is forced by utilizing vibration of both sides of the ink ejecting mechanism. To do it. [Effect] By forcibly supplying the ink, it is possible to improve the printing speed, and by preventing backflow of the ink, a reliable printing operation becomes possible.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an inkjet printer and a printhead mechanism of a plotter that eject liquid ink from a nozzle to perform printing.

[0002]

[Prior Art]

 FIG. 2 shows a print head shape of a conventional inkjet printer or plotter. Conventionally, the ink ejecting mechanism 1 that is present in the ink flow path process is used for ink ejecting only one surface thereof, and the ink transporting method to the ink cavity 3 existing between the ink tank 4 and the ink ejecting nozzle 2 is , It relies on the capillary phenomenon of fluid ink and the balance of pressure.

[0003]

[Problems to be solved by the device]

 In the conventional method, ink is replenished to the ink cavity after being ejected by exciting the ink ejecting mechanism in contact with the ink cavity with a drive circuit (not shown) to eject the ink in the cavity, and The ink replenishment speed cannot keep up with the possible drive speed of the heat generating resistor or piezo transducer, which is the ink ejection mechanism, due to the phenomenon of pressure difference in the ink flow path that causes the ink to flow from the ink tank. Was falling to. In addition, the force acting on the cavity due to the excitation of the ink ejection mechanism also flows backward toward the ink tank, which is an obstacle to ink replenishment.

Further, in the conventional method, the replenishment of ink into the ink cavity after ink ejection depends on the phenomenon due to the pressure difference in the ink flow path between the ink tank and the ink cavity, so the pressure balance is delicate and complicated. If the ink flow path needs to be set properly and the balance is broken, air may be drawn in from the nozzle, and refilling of the cavity may be incomplete, causing defective printing operation.

In view of the above, the present invention forcibly replenishes the ink cavity with ink in order to solve the print speed reduction and print failure due to such influences of the related art, thereby improving the print speed and eliminating the print operation failure. The purpose is to provide a device.

[0006]

[Means for Solving the Problems]

 In order to solve the above problems, in the present invention, by devising the ink flow path for the ink ejection mechanism that was conventionally used only for ink ejection from the nozzle in the ink flow path process, ink cavities are formed on both sides of the ink ejection mechanism. By installing, both sides of the ink ejection mechanism can be used as ink transport means.

[0007]

[Action]

 When the ink jet print head configured as described above and driven by the driving method thereof are driven, ink is ejected from the lower surface of the ink ejection mechanism, and at the same time, the upper surface of the ink ejection mechanism acts to forcibly refill the ink cavity. Therefore, the ink replenishment speed to the ink cavity is increased, and the printing speed can be improved. In addition, the force acting on the ink in the ink flow path before and after the ink cavity is only in the direction of ejecting the ink from the nozzle, and the ink meniscus immediately after ejection does not recede, air is not sucked in, and ink backflow does not occur, resulting in defective printing operation. Decrease.

[0008]

【Example】

 An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows an example of this system in which a piezo transducer is used for the ink ejection mechanism 1 and the Kaiser system is adopted. Ink is supplied from the ink tank 4 and ejected from the ink ejection nozzle 2. In the ink flow path from the ink tank 4 to the ink ejection nozzle 2, in addition to the ink cavity 3 similar to the conventional one, a sub-cavity 5 is adjacent via a piezotransducer of the ink ejection mechanism 1, and a drive circuit (not shown) is provided. The piezo transducer is excited, and both inks in the cavity 3 and the sub-cavity 5 are working.

The ink ejection mechanism 1 is selectively energized based on the print data to fix the print pattern on the print medium, and at the same time, replenishes the ink. Further, when the piezo transducer returns to the normal state, the ink flow path diameter before and after the sub-cavity 5 is optimally set, or the backflow prevention effect of the microvalve 6 forces the ink from the sub-cavity 5 to the ink cavity 3 when ink is re-supplied. Since ink is transported, the ink supply time can be shortened.

Further, since both sides of the piezo transducer are in contact with the ink, the damper effect of the piezo transducer is larger than that of the conventional method, and the vibration damping of the piezo transducer itself is fast, so that a stable ejection effect can be obtained at high speed. FIG. 3 shows another embodiment of the present invention, which is an example of a bubble jet method using a heating resistor in an ink ejection mechanism. While the embodiment using the piezo transducer in FIG. 1 is a system that simultaneously performs different operations of ejecting and filling ink on both sides of the ink ejection mechanism 1, the method using this heating resistor is the ink tank 4 The cavity 3 is configured such that the heating resistor ink ejecting mechanism 7 is sandwiched between the heating element and the ink nozzle 2, and the film boiling phenomenon is simultaneously generated on both sides of the heating resistor. Of the heating resistor ink jetting mechanism 7 to the lower cavity, and simultaneously to the ink jetting from the nozzle, the jetting force of the upper surface of the heating resistor ink jetting mechanism 7 flows to the upper cavity located upstream of the ink flow path. Give rise to.

At this time, the ejection action acts on the side of the ink ejection nozzle 2 and at the same time, a pressure force in the direction opposite to that of the nozzle acts. However, when this and the pressure of the upper ejection mechanism in the nozzle direction cancel each other, the ink ejection is performed. The pressure is increased. Further, since both surfaces of the heat generating resistor 7 are in contact with the liquid ink, the cooling rate after heat generation is improved and the operating frequency of the entire ejection mechanism is improved. Further, since the bubble capacity generated is twice as large as the conventional one, the ink filling pressure at the time of bubble contraction also rises, and the ink refilling speed improves.

[0012]

[Effect of the device]

 As described above, the present invention has the effect of improving the printing speed and realizing a stable ink ejection operation by providing the ink channels so that both sides of the ink ejection mechanism in the ink channel process are used. ..

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of a piezoelectric transducer that uses both sides of an ink ejection mechanism.

FIG. 2 is a diagram showing a conventional print head shape.

FIG. 3 is a diagram showing a bubble type embodiment using both sides of an ink ejection mechanism.

[Explanation of symbols]

 1 Piezo Transducer Ink Ejection Mechanism 2 Ink Ejection Nozzle 3 Ink Cavity 4 Ink Tank 5 Sub Cavity 6 Microvalve 7 Heating Resistor Ink Ejection Mechanism

Claims (1)

[Scope of utility model registration request] 1. In a serial or line print head of an ink jet printer or plotter for ejecting liquid ink from a print head nozzle and fixing it to a print medium such as paper to obtain a print output, both sides of an ejection mechanism as an ink ejection device are in contact with each other. As described above, a print head for an inkjet printer, characterized in that an ink cavity is arranged.