JP2001301167A - Ink-jet recording head and ink-jet recording apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink-jet recording head and an ink-jet recording apparatus whose color reproducibility is improved by turning ink multicolored, recording head is made compact and manufacturing costs are reduced. SOLUTION: Reservoirs 13A and 13B for supplying ink to pressure generation chambers 12A and 12B are formed to both sides of an array of the pressure generation chambers arranged in parallel in a vertical scanning direction which is a direction intersecting a horizontal scanning direction as a move direction of the head. The pressure generation chambers 12A and 12B communicate with the reservoirs 13A and 13B at end parts alternate in the arrangement direction and different in a longitudinal direction. The pressure generation chambers have through hole parts 17A and 17B set to the vicinity of end parts of the side opposite to the communication side to the reservoirs 13A and 13B respectively. Nozzles 21A and 21B are set in an array in the vertical scanning direction to pass through the adjacent pressure generation chambers 12A and 12B paired by extension parts 18A and 18B from the through hole parts respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure generating chamber which communicates with a nozzle for ejecting ink droplets. The pressure generating chamber is formed of a vibrating plate, and a piezoelectric element is provided via the vibrating plate. The present invention relates to an ink jet recording head for discharging ink droplets and an ink jet recording apparatus.

[0002]

2. Description of the Related Art A part of a pressure generating chamber which communicates with a nozzle for discharging ink droplets is constituted by a vibrating plate. Ink jet recording heads that use a vertical-vibration mode piezoelectric actuator that expands and contracts in the axial direction of a piezoelectric element have been put to practical use.

In this method, the volume of the pressure generating chamber can be changed by bringing the end face of the piezoelectric element into contact with the diaphragm, so that a head suitable for high-density printing can be manufactured. There is a problem in that a complicated process of cutting into the comb teeth in accordance with the arrangement pitch of the nozzles and an operation of positioning and fixing the cut piezoelectric element in the pressure generating chamber are required, and the manufacturing process is complicated.

[0004] Such ink-jet recording heads have been widely used as color printers by using color inks, and accordingly, there is a demand for further improving print quality and recording density.

In order to improve the print quality, it is particularly important to improve the color reproducibility. In addition to the use of inks of each color, inks having different ink densities are used. Those that improve reproducibility are effective.

In general, in an ink jet recording head for performing color printing, nozzles are provided in a line in a sub-scanning direction, which is a direction intersecting a main scanning direction, which is a moving direction of the head, for each color. The arranged nozzle rows are arranged side by side in the main scanning direction. However, if the number of nozzle rows is increased with the increase in the number of colors, the size of the head becomes large and the price increases. Therefore, reservoirs are arranged on both sides of one row of voltage actuator rows and pressure generating chambers, the pressure generating chambers are alternately communicated with different reservoirs, and the nozzles are arranged in a staggered manner, thereby forming one row of actuator rows and pressure generating chambers. There is also a method of dividing into two colors.

[0007]

However, when the nozzles are arranged in a staggered arrangement, the nozzles are driven at different timings for each of the staggered arrangements of the nozzles in order to align the dot landing positions on the paper. It is necessary to perform processing such as applying the data by shifting between columns, which increases the cost of the driving circuit.

In view of such circumstances, the present invention provides an ink-jet recording head and an ink-jet recording apparatus which improve the color reproducibility by multicoloring the ink, reduce the size of the recording head, and reduce the manufacturing cost. The task is to provide.

[0009]

According to a first aspect of the present invention, there is provided a flow path forming substrate having a pressure generating chamber communicating with a nozzle, and a pressure change in the pressure generating chamber. In the ink jet recording head having a pressure generating element, each pressure generating chamber is provided on both sides of a row of the pressure generating chambers arranged in a sub scanning direction which is a direction intersecting a main scanning direction which is a moving direction of the head. A reservoir for supplying ink is formed, and each of the pressure generating chambers has a supply port that communicates with the reservoir at at least one or more alternately in the longitudinal direction and at different ends in the longitudinal direction. Ink jet recording wherein a chamber is formed by a shallow groove portion, a through-hole portion and an extended portion, and nozzles communicating with each of the extended portions are provided in a line in the sub-scanning direction. In the head.

In the first aspect, since the nozzle arrays can be driven at the same timing, it is possible to reduce the size and cost while maintaining color reproducibility. Further, the generated pressure can be smoothly transferred to the nozzles, the bubble discharging property can be improved, and the nozzles can be arranged at the same position in the main scanning direction.

According to a second aspect of the present invention, there is provided an ink jet recording head according to the first aspect, wherein the through hole is formed on a side opposite to the supply port.

According to the second aspect, it is possible to enhance the bubble discharging property and to stably eject the ink.

According to a third aspect of the present invention, there is provided an ink jet recording head according to any one of the first and second aspects, wherein the nozzle faces the center of the pressure generating element.

In the third aspect, the nozzle positions are arranged in one line in the sub-scanning direction, and the pressure generating chamber and the nozzles can be symmetrical.

According to a fourth aspect of the present invention, in any one of the first to third aspects, the flow path forming substrate is formed of a silicon single crystal substrate and the pressure generating chamber and the reservoir are formed by anisotropic etching. The ink jet recording head is characterized in that:

According to the fourth aspect, the pressure generating chamber and the nozzle can be easily formed at a high density.

According to a fifth aspect of the present invention, there is provided an ink jet recording head according to any one of the first to third aspects, wherein the flow path forming substrate is formed of a plurality of laminated plates. .

In the fifth aspect, the pressure generating chamber and the nozzle can be easily formed at a high density.

According to a sixth aspect of the present invention, in any one of the first to fifth aspects, the reservoirs on both sides provided in correspondence with the rows of the pressure generating chambers arranged side by side have the same color system respectively. An ink jet recording head is provided with ink.

In the sixth aspect, since the same color ink is disposed in each of the reservoirs on both sides, a color tone shift and color unevenness due to color mixture near the nozzle during cleaning or the like can be suppressed.

A seventh aspect of the present invention is the ink jet recording head according to any one of the first to sixth aspects, wherein the pressure generating element is a piezoelectric element.

In the seventh aspect, the use of the piezoelectric element enables accurate control of ink ejection.

According to an eighth aspect of the present invention, in the seventh aspect, an end of the piezoelectric element is provided in contact with a diaphragm constituting a part of the pressure generating chamber, and each of the pressure generating chambers is provided. An ink jet type recording head is characterized in that the ink jet recording heads are arranged in a line in a row.

In the eighth aspect, ink droplets are ejected by driving a piezoelectric element in a longitudinal vibration mode provided for each pressure generating chamber.

A ninth aspect of the present invention is an ink jet recording apparatus comprising the ink jet recording head according to any one of the first to eighth aspects.

According to the ninth aspect, it is possible to realize an ink jet recording head with improved color reproducibility of the head and higher density.

[0027]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail based on embodiments.

(Embodiment 1) FIG. 1 is an exploded perspective view of an ink jet recording head of the present invention, FIG. 2 is a top view of a flow path forming substrate, FIG. 3 is a sectional view taken along line AA 'of FIG. It is -B 'sectional drawing.

As shown in the figure, the flow path forming substrate 10 is made of a silicon single crystal substrate, and a pressure generating chamber defined by a plurality of partitions 11 by, for example, azimuthal etching is formed on a surface layer on one surface side. 12 (12A, 12B) are juxtaposed in the width direction. Also, on both sides of the row of each pressure generating chamber 12, a first reservoir 13A and a second reservoir 13B for supplying ink to each pressure generating chamber 12 flow by anisotropic etching similarly to the pressure generating chamber 12. It is formed penetrating the path forming substrate. The pressure generating chamber 12A communicates with the first reservoir 13 and the pressure generating chamber 12B communicates with the second reservoir 13B.

Here, the anisotropic etching may be either wet etching or dry etching. The silicon single crystal plate is etched halfway in the thickness direction (half etching) to form the pressure generating chamber 12. Are formed shallow without penetrating. Note that the half etching is performed by adjusting the etching time.

In the present embodiment, the pressure generating chamber 12 is
One of the longitudinal ends is formed by etching so as to communicate with the first reservoir 13A or the second reservoir 13B, and an island portion 14 is left substantially at the center of the one end in the width direction.

By providing the island portions 14, two ink supply ports 15 for supplying ink from the reservoir 13 to the respective pressure generating chambers 12 are defined. Specifically, the ink supply ports 15 are alternately formed at different ends of the pressure generation chambers 12 arranged side by side, and each pressure generation chamber 12 is connected to the first reservoir 13A through the ink supply ports 15. And one of the second reservoirs 13B. That is, for each row of one pressure generation chamber 12, half of the pressure generation chambers 12 are divided into the first and second reservoirs 13.
A and 13B communicate with each other.

The pair of pressure generating chambers 12A and 12B
However, the rows of the pressure generating chambers 12 are alternately arranged in the width direction to form a row of the pressure generating chambers 12. The nozzle plate 20 in which the nozzles 21A and 21B are drilled is bonded via an adhesive or a heat welding film.

Here, a pair of two pressure generating chambers 12A, 12A
Each of the nozzles 21A and 21B of B extends from the through-hole 17 so that the pressure generating chambers 12A and 12B have the same longitudinal position.
And a flow path formed toward the center through the pressure generation chambers 12A and 12B.
Nozzles 21A and 21B communicate with each other in the sub-scanning direction.
A row is provided.

As described above, the ink supply port 15, the pressure generating chamber
By forming a flow path from the through-hole portion 17, the extension portion 18, and the reservoir 13 to the nozzle 21, the ink can flow without stagnation, and the retention of bubbles in the pressure generating chamber can be prevented.

The pressure generating chambers arranged in parallel as described above
The pressure generating chambers 12 are provided in a plurality of rows so that the positions in the width direction of the pressure generating chambers 12 are the same, ink is supplied to the pressure generating chambers 12 arranged in parallel from ink cartridges of different colors, and ink of each color is ejected. It is supposed to be. On the other hand, the surface of the flow path forming substrate 10 on the pressure generating chamber 12 side is sealed with a vibration plate 30, and a head case having an ink supply path 41 on the vibration plate 30 further connected to a plurality of ink cartridges (not shown). 40 is fixed, and the ink supply path 41 and the
The first and second reservoirs 13A and 13B are communicated with each other via ink supply communication holes 31 provided in the diaphragm 30.

Further, in the area corresponding to the rows of the pressure generating chambers 12 on the vibration plate 30, the number of the piezoelectric elements 50 is arranged in rows for each of the pressure generating chambers 12. This piezoelectric element 50
Is an island portion 30a whose tip is provided on the diaphragm 30.
Is in contact with These piezoelectric elements 50 are made of a piezoelectric material 51.
And electrode forming materials 52 and 53 are vertically and alternately sandwiched in a sandwich shape, and an inactive region that does not contribute to vibration is fixed to the fixed substrate 60. The fixed substrate 60, the vibration plate 30, the flow path forming substrate 10, and the nozzle plate 20 are integrally fixed via the head case 40.

In the ink jet recording head thus configured, ink is supplied to the reservoirs 13A and 13B via an ink supply path 41 communicating with the ink cartridge, and each pressure generating chamber 12 is supplied via an ink supply □ 15. Distributed to In practice, the piezoelectric element 50 is contracted by applying a voltage to the piezoelectric element 50. As a result, the vibration plate 30 is pulled up together with the piezoelectric element 50, the volume of the pressure generating chamber 12 is expanded, and ink is drawn into the pressure generating chamber 12. Then, after filling the inside up to the nozzle 21 with ink, the voltage applied to the electrode forming materials 52 and 53 of the piezoelectric element 50 is released according to a recording signal from the drive circuit, and the piezoelectric element
50 is extended and returns to the original state. Thereby, the diaphragm 30
The pressure generating chamber 12 is also displaced and returns to the original state, so that the pressure generating chamber 12 contracts, the internal pressure increases, and ink droplets are ejected from the nozzle 21.

Such an ink jet type recording head is mounted on an ink jet type recording apparatus so that a nozzle row is along a main scanning direction which is a moving direction of the head. Figure 4
FIG. 1 is a schematic view showing an example of the ink jet recording apparatus.

As shown in FIG. 4, recording head units 1A and 1B having ink jet recording heads are provided with detachable cartridges 2A and 2B constituting ink supply means, and are equipped with these recording head units 1A and 1B. The carriage 3 is provided on a carriage shaft 5 attached to the apparatus main body 4 so as to be movable in the axial direction. The recording head units 1A and 1B discharge, for example, a black ink composition and a plurality of color ink compositions, respectively. In the present embodiment, three rows of the pressure generating chambers 12 of the ink jet recording head are provided, and a nozzle row of six colors is provided as a whole.

The nozzle rows arranged as described above are supplied with ink from ink cartridges 1A and 1B of different colors, respectively, and are provided with six color inks, in this embodiment, black (B), yellow (Y), Cyan (C), light cyan (L
Each color of C), magenta (M) and light magenta (LM) is ejected.

In the present embodiment, of these multiple color inks, dark and light inks of the same color are ejected from the nozzle rows adjacent to each other, and black and yellow are adjacent to each other. The nozzles are ejected from each of the nozzle rows.

The driving force of the driving motor 6 is transmitted to the carriage 3 via a plurality of gears and a timing belt 7 (not shown), so that the recording head units 1A and 1
The carriage 3 on which B is mounted is moved along the carriage shaft 5. On the other hand, the apparatus main body 4 is provided with a platen 8 along the carriage shaft 5, and a recording sheet S, which is a recording medium such as paper fed by a paper feed roller (not shown), is wound around the platen 8. It is designed to be transported.

In the present embodiment, a cap 9 is provided on the side of the platen 8 which is the end of the carriage 3 in the moving direction, and a suction pump (not shown) is connected to the cap 9 so-called A cleaning operation is performed. Note that the cap 9 also caps the head end surface of the ink jet recording head that is waiting for printing for a predetermined time or more to prevent the nozzles from drying.

In such an ink jet recording apparatus, a secondary color is created by superimposing colors on the recording sheet S in order to perform color printing.

In the present embodiment, since the nozzles 21A and 21B are provided in one line in the sub-scanning direction,
A and 21B can be driven with the same timing and the same column of print data.

The pressure generating chambers 12A and 12B, which are adjacent to the pressure generating chambers 12 arranged side by side, each have a through-hole
A, 17B are provided, and the extension parts 18A, 18B are provided, so that the nozzles 21A, 21B communicating with the respective pressure generating chambers 12A, 12B are provided.
Can be arranged in one row, the color reproducibility can be improved, the head can be downsized, and the manufacturing cost can be reduced.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of an ink jet recording head according to a first embodiment of the present invention.

FIG. 2 is a top view of a flow path forming substrate of the inkjet recording head according to Embodiment 1 of the present invention.

FIG. 3 is a cross-sectional view of the inkjet recording head according to the first embodiment of the present invention.

FIG. 4 is a schematic perspective view of the ink jet recording apparatus according to the first embodiment of the present invention.

[Explanation of symbols]

 10 Flow path forming substrate 12 Pressure generating chamber 13A 1st reservoir 13B 2nd reservoir 14 Island 15A, 15B Ink supply port 16A, 16B Ink supply path 17A, 17B Through hole 18A, 18B Extension part 20 Nozzle plate 21A, 21B Nozzle 30 Vibration plate 40 Head case 41 Ink supply path 50 Piezoelectric element 60 Fixed substrate

Continued on the front page F term (reference) 2C056 EA11 EA15 EA23 EA24 ED07 EE18 FA04 FA10 HA05 HA07 HA16 HA17 HA22 JA13 KC22 2C057 AF80 AF91 AF93 AG12 AG30 AG48 AG53 AG70 AN01 AP02 AP25 AP34 AQ02 BA04 BA14

Claims (9)

[Claims] 1. An ink jet type recording head comprising: a flow path forming substrate in which a pressure generating chamber communicating with a nozzle is formed; and a pressure generating element for generating a pressure change in the pressure generating chamber. A reservoir for supplying ink to each pressure generating chamber is formed on both sides of a row of the pressure generating chambers arranged in a sub-scanning direction which is a direction intersecting a certain main scanning direction, and each of the pressure generating chambers is A supply port communicating with the reservoir at at least one end alternately different in the longitudinal direction in the arrangement direction, wherein the pressure generating chamber is formed of a shallow groove portion, a through-hole portion, and an extending portion, and An ink jet recording head, wherein nozzles communicating with each of the extending portions are provided in one row in the sub-scanning direction. 2. The ink jet recording head according to claim 1, wherein a through hole is formed on a side opposite to the supply port. 3. An ink jet recording head according to claim 1, wherein the nozzle faces the center of the pressure generating element. 4. An ink jet printer according to claim 1, wherein said flow path forming substrate is made of a silicon single crystal substrate, and said pressure generating chamber and said reservoir are formed by anisotropic etching. Type recording head. 5. The ink jet recording head according to claim 1, wherein the flow path forming substrate is formed of a plurality of laminated plates. 6. The ink container according to claim 1, wherein inks of the same color are respectively arranged in the reservoirs on both sides provided corresponding to the rows of the pressure generating chambers arranged in parallel. Inkjet recording head. 7. The ink jet recording head according to claim 1, wherein the pressure generating element is a piezoelectric element. 8. The pressure generating chamber according to claim 7, wherein an end of the piezoelectric element is provided in contact with a vibration plate constituting a part of the pressure generating chamber, and the piezoelectric element is arranged in a row in a direction in which the piezoelectric element is arranged. An ink jet recording head, which is provided. 9. An ink jet recording apparatus comprising the ink jet recording head according to claim 1.