JPH11207949A - Water mill type ink jet head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to realize an ink discharge at a high velocity using a low drive voltage without selecting the kind of ink. SOLUTION: This water mill type ink jet head 21 has a cylindrical casing 1 with an ink supply aperture 3 and an ink discharge aperture 5 formed in the circumferential direction and has such a function that the ink 17 supplied into the casing 1 through the ink supply aperture 3 is discharged onto a recording paper, in ink droplets, from the ink discharge aperture 5 to record an image. In addition, the internal space of the casing 1 is divided into plural liquid chambers 13 by partitioning the space with plural pieces of blade 11 installed radially centered around a rotary shaft 7 mounted in a freely rotating manner inside the casing 1. At the same time, a water mill type propeller 9 is provided which moves the liquid chambers 13 sequentially by rotation to the ink supply aperture 3 and the ink discharge aperture 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water wheel type ink jet head for recording an image or the like by discharging ink droplets onto a recording sheet, and more particularly, to a water wheel type propeller having a plurality of blades in a radial shape. The present invention relates to a water wheel type ink jet head having a structure provided rotatably in a casing and discharging ink liquid supplied between adjacent blades from a discharge port of the casing while rotating a propeller.

[0002]

2. Description of the Related Art There is a piezoelectric element type in which a piezo element or the like is used as a driving source for ejecting ink, as an ink jet head which discharges ink by pressurization and collides with recording paper to perform printing. This piezoelectric element type ink jet head allows the inner volume of the liquid chamber to be variable by the piezo element,
By applying a drive pulse to the piezo element, the internal volume of the liquid chamber is changed, and the suction and discharge of ink are performed by the pressure difference in the liquid chamber caused by the change, and the ink droplets are discharged to recording paper to print an image or the like. Record.

[0003] Some ink jet heads are of a bubble type in which bubbles are generated by a heating element to discharge ink. This bubble-type ink jet head has a heating element provided in a nozzle, generates air bubbles in the nozzle by heating the heating element, discharges ink in the nozzles as droplets by the expansion force of the bubbles, and generates a driving voltage. The bubbles are eliminated by cutting off the ink, and the ink is caused to flow into the nozzles by capillary action. By repeating this, an image or the like is recorded on the recording paper.

[0004]

However, the above-described piezoelectric element type ink jet head requires a high drive voltage to obtain a mechanical amount such as pressure and vibration, and has a problem of low energy efficiency. In addition, the bubble-type ink-jet head requires a time from application of a driving pulse to the heating element to generation of bubbles due to heat generation efficiency of the heating element and heat between the heating element (solid) and ink (fluid). Since the delay is caused by various factors such as the transmission rate and the temperature rise characteristics of the ink itself, it is difficult to increase the response speed, and the ink is required to have heat resistance, and there is a disadvantage that the ink type is limited. .

[0005] Further, in the case of performing continuous (continuous) ink discharge, ink charging is required, which also has the disadvantage that the type of ink is limited.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a water wheel type ink jet head which can discharge at a high speed with a low driving voltage, regardless of the type of ink.

[0007]

According to a first aspect of the present invention, there is provided a water wheel type ink jet head having a cylindrical casing having an ink supply port and a discharge port formed in a circumferential direction, and through the ink supply port. A water wheel type ink jet head for recording an image or the like by discharging ink supplied into the casing from the discharge port as ink droplets onto a recording sheet, and provided rotatably in the casing with a rotation axis as a center. A water wheel type propeller is provided which partitions the space in the casing into a plurality of liquid chambers with a plurality of radially provided blades, and sequentially moves the liquid chambers with respect to the ink supply port and the discharge port by rotation. It was done.

In this water-jet type ink jet head, the plurality of liquid chambers are sequentially moved to the ink supply port and the discharge port by the rotation of the propeller, thereby enabling high-speed ink supply and discharge. In addition, since heat resistance and charging properties of the ink are not required, restrictions on physical properties of the ink are reduced.

In this water-jet type ink jet head, the driving force of the propeller is a supply pressure of the ink liquid into the casing. In this water-jet type inkjet head, when ink is supplied to the liquid chamber at a predetermined supply pressure,
When the ink strikes the blades, a moment is generated in the propeller,
The propeller rotates without using a special drive.

According to a third aspect of the present invention, there is provided a water wheel type ink jet head having an elastically deformable body which is deformed by an ink supply pressure into a casing to substantially increase the inner volume of the liquid chamber. In this water-jet type inkjet head, when ink is supplied to the liquid chamber, the elastically deformable body is deformed, the ink supply pressure is maintained in a state converted to the deformation force of the elastically deformable body, and when the liquid chamber is opened. Then, the ink droplets can be taken out as ejection force.

According to a fourth aspect of the present invention, there is provided a water wheel type ink jet head in which ink droplets are ejected from the ejection ports at regular time intervals by rotating the propeller. In this water-jet type ink jet head, the liquid chamber communicates with the discharge port at regular time intervals by rotating the propeller at a constant speed, so that ink droplets can be continuously discharged.

According to a fifth aspect of the present invention, there is provided a water wheel type ink jet head wherein a plurality of pairs of the ink supply ports and the discharge ports are provided in a circumferential direction of the casing. In this water-jet type inkjet head, the liquid chamber passes through a plurality of pairs of ink supply ports and discharge ports in one rotation of the propeller,
The number of ink supply and ejection increases. In addition, the interval between the supply and discharge times of the ink is shortened. Further, there are a plurality of ink droplet ejection directions.

According to a sixth aspect of the present invention, there is provided a water wheel type ink jet head in which the arrival of the ink droplets on the recording paper is controlled by a shutter mechanism which opens and closes based on recording data. In this water-jet type inkjet head, the shutter mechanism opens and closes based on the recording data,
The arrival of the ink droplets on the recording paper can be controlled on demand.

According to a seventh aspect of the present invention, there is provided a water wheel type ink jet head wherein the driving force of the propeller is an electrostatic force. In this water-jet type ink jet head, by driving the propeller by electrostatic force, the drive voltage of the propeller can be reduced, and moreover, reliable and stable rotation can be achieved.

According to another aspect of the present invention, the propeller is intermittently rotated to discharge ink droplets only at a discharge timing based on print data. In this water-jet type ink jet head, the rotation of the propeller according to the ejection timing becomes possible, and the on-demand recording by controlling the rotation of the propeller becomes possible.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a water wheel type ink jet head according to the present invention will be described below with reference to the drawings. FIG. 1 is a conceptual diagram showing a water turbine type ink jet head according to a first embodiment of the present invention.

An ink supply port 3 is provided at the both ends of a closed flat cylindrical casing 1 at circumferential intervals.
A discharge port 5 is provided. Inside the casing 1, a water wheel type propeller 9 which is rotatable by aligning the rotation axis 7 with the center axis of the casing 1 is incorporated. Propeller 9
Has a plurality of blades 11 radially provided at equal intervals on the outer periphery of the rotating shaft 7. No gap is formed between the tip of the blade 11 and the inner peripheral surface 1a of the casing 1.

Accordingly, the space in the casing 1 is partitioned by the blades 11 of the propeller 9 into a plurality of liquid chambers 13 in the circumferential direction. The liquid chamber 13 is rotated in the circumferential direction by rotation of the propeller 9, and communicates with the ink supply port 3 and the discharge port 5 sequentially. A supply path 15 is connected to the ink supply port 3, and ink 17 pressurized from a pressure chamber (not shown) is supplied to the ink supply port 3 via the supply path 15. Supply path 1
The ink supply direction 5 is shifted from the rotation center of the propeller 9 to the outside of the rotation radius. In this example, by shifting the ink supply direction to the right from the rotation center of the propeller 9,
The ink 17 supplied from the ink supply port 3 is
Is rotated counterclockwise.

An elastically deformable body (for example, a metal flake) 19 constituting a part of the inner wall of the liquid chamber 13 is provided at the base end of the adjacent blades 11 forming the liquid chamber 13. The metal flake 19 is deformed by the supply pressure of the ink 17 flowing into the liquid chamber 13 from the ink supply port 3, and substantially increases the internal volume of the liquid chamber 13. Therefore, the liquid chamber 13 storing the ink 17 by deforming the metal flake 19
Is separated from the ink supply port 3 by the rotation of the propeller 9, and is sealed at a high pressure from outside the liquid chamber 13.

The operation of the water-jet type ink jet head 21 thus configured will be described with reference to FIG. FIG. 2 is an explanatory diagram showing a process of an ink discharging operation of the water wheel type inkjet head of the first embodiment. As shown in FIG. 2A, the ink 17 pressure-fed from a pressure chamber (not shown) is supplied to the ink supply port 3 via a supply path 15 and flows into the liquid chamber 13 in the casing 1. When the ink 17 flows into the liquid chamber 13, the metal sheet 19 is supplied by the supply pressure of the ink 17.
Is elastically deformed, the inner volume of the liquid chamber 13 is increased, and a counterclockwise moment is generated in the propeller 9 to rotate the propeller 9.

The propeller 9 rotates continuously or intermittently, but at a substantially constant speed. The flow of the ink 17 into the liquid chamber 13 and the discharge of the ink 17 from the liquid chamber 13 are synchronized with the arrival cycle of the ink 17 into the liquid chamber 13. The ink 17 may be continuously supplied to all the liquid chambers 13. Further, it may be supplied only at the ejection timing based on the print data. In this case, the propeller 9 rotates intermittently. Note that FIG. 2 shows that the ink 1
7 is supplied as an example.

The liquid chamber 13 rotates and moves in a direction approaching the discharge port 5 as shown in FIG. 2B with the ink 17 filled with the rotation of the propeller 9. And
As shown in FIG. 2C, when the liquid chamber 13 reaches the discharge port 5, the liquid chamber 13 which has been in a sealed state is opened by the discharge port 5, and the metal flake 19 is restored to its original shape by elastic force. I do. As a result, the internal volume of the liquid chamber 13 is reduced to the original volume, and a part of the ink 17 filling the liquid chamber 13 is discharged from the discharge port 5 as ink droplets 17a toward a recording sheet (not shown). Will be done.

According to the water wheel type ink jet head 21 configured as described above, the plurality of liquid chambers 13 formed between the blades 11 of the propeller 9 can be sequentially moved and rotated by the rotation of the propeller 9 to discharge at high speed. Thus, it is possible to discharge an appropriate ink droplet. In addition, since heat resistance and chargeability of the ink 17 are not required, the limitation of the physical properties of the ink 17 is reduced, and a wider variety of inks can be used as compared with the related art. For example, as the ink, a substance that becomes liquid, sol, or gel under some conditions, such as water, a solvent, a wax that is solid at room temperature, which is melted by heat, and the like can be applied in addition to a liquid in which a coloring agent is dissolved in a liquid.

Next, a second embodiment of a water wheel type ink jet head according to the present invention will be described with reference to FIG. FIG. 3 is an enlarged view of a main part showing a water wheel type ink jet head of a second embodiment. In the water wheel type ink jet head 31 according to this example, a spring 33 as an elastic member is disposed between the rotating shaft 7 and the thin metal piece 19, and the elastic return force of the thin metal piece 19 is urged by the spring 33. I have. The compression force of the spring 33 is smaller than the ink supply pressure acting on the metal flake 19.

According to the water wheel type ink jet head 31 structured as described above, the elastic restoring force of the thin metal piece 19 can be increased, and the ejection force at the time of ink ejection can be increased, thereby increasing the ejection speed.

Next, a third embodiment of a water wheel type ink jet head according to the present invention will be described with reference to FIG. FIG. 4 is a conceptual diagram showing a water wheel type inkjet head according to the third embodiment. Water-jet type inkjet head 4 according to this example
1 is provided with a plurality of pairs (two pairs in this example) of ink supply ports 3 and discharge ports 5 in the circumferential direction of the casing 1.

According to the water wheel type ink jet head 41 configured as described above, by providing a plurality of pairs of ink supply ports 3 and discharge ports 5 in one casing 1, ink droplets per one rotation of the propeller 9 are provided. The number of ejections can be increased, and the recording speed can be increased. Also,
At the same time, recording on a plurality of recording sheets can be enabled.

Although not shown, the water wheel type ink jet head according to the present invention may control the arrival of the ink droplets on the recording paper by a shutter mechanism that opens and closes based on the recording data. According to the water-jet type inkjet head configured as described above, it is possible to perform on-demand recording by rotating the propeller at substantially the same speed and controlling the inflow of ink into the liquid chamber by the shutter mechanism, for example. it can. In this case, the liquid chambers may be in an ink-filled state or an empty state depending on the recording data, but the ink residence time in each liquid chamber 13 is constant.

Furthermore, the water wheel type ink jet head according to the present invention forcibly rotates the propeller using a known driving means such as an electrostatic force, an electromagnetic force (motor), or vibration (ultrasonic motor). It may be. According to the waterwheel type inkjet head configured as described above, it is possible to perform an on-demand type recording in which the propeller is rotated only at the timing of discharging the ink droplets according to the recording data. In this case, all the liquid chambers are filled with ink, and the residence time of the ink in each liquid chamber 13 is different.

[0030]

Next, the results of actually manufacturing a water wheel type ink jet head according to the present invention and discharging ink under the following conditions will be described.

<Conditions> The discharge port formed in the casing had a diameter of 10 μm. -The recording paper was vertically arranged at a distance of 1 mm from the discharge port, and was conveyed at a speed of 40 mm / s. The propeller was rotated at a rotation speed of 100 rps by a pulse motor, and ink droplets were ejected at a cycle of 800 Hz.

As a result, it was confirmed that ink droplets adhered to the recording paper at a pitch of 50 μm.

[0033]

As described above, according to the water-jet type ink jet head of the first aspect of the present invention, the plurality of liquid chambers formed between the blades of the propeller are sequentially moved by the rotation of the propeller and discharged. It is possible to discharge ink droplets at a high speed,
Since heat resistance and chargeability of the ink are not required, restrictions on the physical properties of the ink are reduced and a wide variety of inks can be used.

According to the second aspect of the present invention, the propeller is driven by the ink supply pressure to the liquid chamber, so that the propeller can be rotated without using a dedicated driving device.

According to the third aspect of the present invention, since the elastically deformable body for expanding the inner volume of the liquid chamber by the ink supply pressure is provided, the ink supply pressure is temporarily converted into the deformation force of the elastically deformable body. Thereafter, the ink can be taken out as the ejection force of the ink droplet, and the ink supply pressure can be effectively used.

According to the water-jet type ink jet head of the fourth aspect, since the ink droplets are ejected from the ejection ports at regular time intervals by the rotation of the propeller, the structure is relatively simple and continuous. Ink can be ejected.

According to the water wheel type ink jet head of the fifth aspect, since a plurality of pairs of ink supply ports and discharge ports are provided in the circumferential direction of the casing, the number of ink droplet discharge per rotation of the propeller can be increased. In addition, the recording speed can be increased, and at the same time, recording on a plurality of recording sheets becomes possible.

According to the water wheel type ink jet head of the present invention, the arrival of the ink droplets on the recording paper is controlled by the shutter mechanism which opens and closes based on the recording data. Can be made possible.

According to the water jet type ink jet head of the present invention, the propeller is driven by the electrostatic force, so that the propeller can be rotated at a low voltage, reliably and stably.

According to the water jet type ink jet head of the eighth aspect, the ink droplets are ejected by intermittently rotating the propeller only at the ejection timing, so that the on-demand recording can be performed only by controlling the rotation of the propeller. be able to.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram showing a water turbine type inkjet head according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram illustrating a process of an ink discharging operation of the water wheel type inkjet head according to the first embodiment.

FIG. 3 is an enlarged view of a main part showing a water turbine type ink jet head according to a second embodiment.

FIG. 4 is a conceptual diagram illustrating a water wheel type inkjet head according to a third embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Casing 3 Ink supply port 5 Discharge port 7 Rotating shaft 9 Propeller 11 Blade 13 Liquid chamber 17 Ink 19 Metal flake (elastic deformation body) 21, 31, 41 Water-jet type inkjet head

Claims (8)

[Claims] A cylindrical casing (1) having an ink supply port (3) and a discharge port (5) formed in a circumferential direction;
A water wheel type ink jet head for recording an image or the like by discharging ink (17) supplied into the casing (1) through the ink supply port (3) as ink droplets from the discharge port (5) to recording paper. (21) A plurality of blades (11) rotatably provided in the casing (1) and provided radially around a rotation shaft (7) to divide a space in the casing (1) into a plurality of blades. A water wheel type propeller (9) for partitioning the liquid chamber (13) and sequentially moving the liquid chamber (13) with respect to the ink supply port (3) and the discharge port (5) by rotation; A water wheel type ink jet head (21), characterized in that: 2. A water wheel type inkjet head (21) according to claim 1, wherein the driving force of said propeller (9) is a supply pressure of an ink liquid into said casing (1). 3. An elastically deformable body which is deformed by an ink supply pressure into said casing (1) and substantially expands the inner volume of said liquid chamber (13) is provided in said liquid chamber (13). The waterwheel type inkjet head (21) according to claim 1, characterized in that: 4. A water wheel type ink jet head (21) according to claim 1, wherein said propeller (9) is rotated to discharge ink droplets from said discharge port (5) at regular time intervals. 5. A water wheel type inkjet head according to claim 1, wherein a plurality of pairs of said ink supply port (3) and said discharge port (5) are provided in a circumferential direction of said casing (1). 21). 6. A water wheel type ink jet head according to claim 1, wherein the arrival of said ink droplets on said recording paper is controlled by a shutter mechanism which opens and closes based on recording data. 7. The water-jet type inkjet head according to claim 1, wherein the driving force of the propeller is an electrostatic force. 8. A water wheel type ink jet head (21) according to claim 7, wherein said propeller (9) is intermittently rotated to discharge ink droplets only at a discharge timing based on print data.