JPH0516388A - Ink jet printing head device and its driving method - Google Patents

Abstract

PURPOSE:To restrain pressure in the reverse direction of nozzle to be generated in an ink jet head in ink jet operation. CONSTITUTION:A main ink passage 2 is branched so as to construct a looped passage 1. Jet frequency and dimensions are adjusted, so that pressures in other direction than the direction of nozzle to be generated at ink jet operation are canceled reciprocally so as to be reduced. Thus, flying distance of jetted ink is increased, printing speed of a device is improved because resupplying time of the ink is shortened, and error of a device mechanism can be absorbed as well.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet type print head mechanism which is widely used as a printing system for printing devices such as printers and plotters.

[0002]

2. Description of the Related Art FIG. 3 is a sectional view of a conventional printhead mechanism for an ink jet. In the conventional method, the ink flow path from the ink tank 5 to the ink ejection nozzle 4 is a one-way flow path without a tributary, and the ink ejection mechanism 3 installed in the vicinity of the ink ejection nozzle 4 (in this example, the bubble jet method uses a heating resistor). Ink is ejected from the nozzle.

[0003]

A drawback of the known ink jet print head is that when ink is ejected, a pressure that pushes the ink back toward the tank is generated in addition to a pressure that pushes the ink toward the nozzle. . The pressure acting in the direction of the tank lowers the ejection efficiency of the print head, and the flight distance of ejected ink also becomes shorter. Further, the pressure in the tank direction generated at this time is a negative pressure with respect to the ink supply pressure after the ink is ejected, which causes a decrease in the speed at which the ink is supplied, resulting in a decrease in the printing speed.

Therefore, an object of the present invention is to reduce the negative pressure in the ink tank direction at the time of ejecting ink in an ink jet type print head device, and to increase the printing speed while increasing the ink flying distance. It is to supply the head.

[0005]

In order to solve the above-mentioned problems, the present invention provides a loop-shaped ink flow passage near the ink ejection mechanism of an ink jet type print head so that ink flows into the ink flow passage toward the tank. , The ink flowing into the loop-shaped tributary returns to the tank direction, and the pressure generated in the ink tank direction at the time of ink ejection is constructed by constructing an ink flow path that merges at an acute angle in the same direction as the ink main flow direction. It was possible to reduce.

[0006]

When the ink jetting operation is carried out in the print head having the ink flow path constructed as described above, conventionally, a part of the pressure in the tank direction out of the pressures acting in either the nozzle direction or the tank direction is diverted. The pressure is propagated through the ink in the tributary and as a medium. This propagated pressure acts on the tank side of the flow path along the ink supply direction of the main ink flow to increase the ink supply pressure. That is, since the pressure on the tank side of the ink ejecting mechanism increases, the pressure generated in the ink ejecting mechanism works efficiently toward the nozzle, the flight distance of ejected ink is improved, and the ink supply speed is also increased.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view of an ink jet type print head according to the present invention, which shows a bubble jet type structure in this embodiment. The ink 6 is carried from the ink tank 5 to the ink ejection nozzle 4 by the main flow path 2 to the ink ejection nozzle 4, and the ink is ejected from the nozzle 4 by the heating resistor 3 of the ink ejection mechanism provided in the middle of the main flow path 2. It is equivalent to the conventional technology.

This flow path is constructed by stacking glass or metal plate etching members. The number of stacked layers is increased to form a loop-shaped sub flow path 1 and each flow path is separated from the ink tank 5 in a stationary state. Fill with ink 6.
The main flow path of the loop-shaped ink flow path 1 is provided in parallel with the main ink flow path 2 from the vicinity of the heating resistor 3 toward the ink tank 5. The main ink flow path 2 and the loop-shaped ink flow path 1 are connected from the vicinity of the heating resistor 3 by a flow path having an upper right slope. Also on the ink tank 5 side, the main ink flow passage 2 and the loop-shaped ink flow passage 1 are connected by a flow passage having the same gradient.

FIG. 2 shows a state in which an ink ejecting operation is performed by the heating resistor 3. In FIG. 2, by applying a pulse to the heating resistor 3, heat is generated in the valve 7, and pressure is applied to the ink due to the volume change. Since the pressure at this time spreads in all directions from the surface of the bubble 7, in the conventional method, the pressure from above the bubble pressed the upper wall of the ink flow path and escaped to either the nozzle 4 direction or the tank 5 direction. In the structure of this embodiment, the pressure is transmitted through the ink in the loop-shaped flow passage 1 and is transmitted to the rear of the flow passage. The pressure transmitted at this time is applied in the ink supply direction when entering the main ink flow path 2 from the loop-shaped ink flow path 1, so that the pressure on the tank side rises and prevents the pressure increase from the bubble 7 to the tank 5 direction.

At this time, by appropriately setting the heat generation cycle of the heat generating resistor, each flow passage cross-sectional area, loop flow passage length, ink clay, etc., all the pressures in all directions when the bubble 7 is generated other than the pressure in the nozzle 4 direction. It is possible to offset and increase the pressure in the nozzle 4 direction required for ink ejection. That is, the ejection energy applied to the flying ink is increased and the flight distance is improved. Further, since the ink supply pressure also rises, the speed of ink resupply at the time of bubble contraction is improved.

[0011]

Due to the change in the pressure balance before and after the ink ejecting mechanism due to the above ink ejecting operation, the pressure generated by the ink ejecting operation is efficiently used for the ink ejecting and the ink flying distance is increased. In the inkjet printing method, since the print head and print medium are not in contact with each other, it is necessary to absorb variations due to the mechanical accuracy of the device and variations in the thickness and shape of the print medium, but to improve the flight distance of the ink. Therefore, the variation can be absorbed.

Further, since the ink behind the ink ejection mechanism is also pushed out toward the nozzle side, the ink is forcibly supplied and the preparation time for the next ink ejection operation is shortened. In order to shorten the printing time of the inkjet method, it is necessary to improve the liquid ink supply property rather than the electrical controllability related to ink ejection, but in the present invention, the printing time of the printing apparatus can be shortened from the above effects.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of an inkjet head structure according to the present invention.

FIG. 2 is a cross-sectional view showing a state during operation of the embodiment.

FIG. 3 is a cross-sectional view showing an example of a conventional inkjet head structure.

[Explanation of symbols]

1 loop ink flow path 2 ink main flow path 3 Heating resistor of ink ejection mechanism 4 Ink ejection nozzle 5 ink tank 6 liquid ink 7 bubble

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[Procedure amendment]

[Submission date] August 9, 1991

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] 0002

[Correction method] Change

[Correction content]

[0002]

BACKGROUND OF THE INVENTION The print head mechanism sectional view for a conventional Inkuji E Tsu preparative shown in FIG. In the conventional method, the ink flow path from the ink tank 5 to the ink ejection nozzle 4 is a one-way flow path without a tributary, and the ink ejection mechanism 3 installed in the vicinity of the ink ejection nozzle 4 (in this example, the bubble jet method uses a heating resistor). Ink is ejected from the nozzle.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0006

[Correction method] Change

[Correction content]

[0006]

When the ink jetting operation is carried out in the print head having the ink flow path constructed as described above, conventionally, a part of the pressure in the tank direction out of the pressures acting in either the nozzle direction or the tank direction is diverted. When the ink in the tributary is used as a medium, the pressure is propagated. This propagated pressure acts on the tank side of the flow path along the ink supply direction of the main ink flow to increase the ink supply pressure. That is, since the pressure on the tank side of the ink ejecting mechanism increases, the pressure generated in the ink ejecting mechanism works efficiently toward the nozzle, the flight distance of ejected ink is improved, and the ink supply speed is also increased.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0010

[Correction method] Change

[Correction content]

[0010] By setting heating cycle and the flow path cross-sectional area of this time the heating resistor, the loop flow path length, ink viscosity or the like as appropriate, other than the nozzle 4 the direction of pressure of the omnidirectional pressure upon the bubble 7 generated It is possible to offset the above and increase the pressure in the nozzle 4 direction required for ink ejection. That is, the ejection energy applied to the flying ink is increased and the flight distance is improved. Further, since the ink supply pressure also rises, the speed of ink resupply at the time of bubble contraction is improved.

Claims (2)

[Claims] 1. A main flow path from an ink supply portion to a nozzle in a print head, which is an ink jetting mechanism in a printing apparatus in which liquid ink is jetted from a nozzle by a physical or electrical method and fixed by jetting it onto a print medium. An ink jet print head device characterized in that a sub-flow passage for sending ink in a direction opposite to a nozzle is provided near an ink ejecting mechanism portion inside. 2. A head driving method using the head device according to claim 1, wherein the reverse pressure at the time of ink ejection is reduced to increase the ink flight distance and increase the ink supply speed.