JP2725688B2 - Micro kick ink jet head - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet printer employing a micro kick system, and more particularly to a micro kick ink jet head used therein.

[0002]

2. Description of the Related Art In general, an ink jet printer has a feature that it can perform printing on a recording medium such as recording paper in a non-contact manner. In other words, a print head of an ink jet printer is provided with a plurality of ink ejection nozzles for ejecting ink droplets. By selectively ejecting ink droplets from these ink ejection nozzles based on print data, printing is performed on a recording medium. Done. For this reason, the ink jet printer has advantages in that there are few restrictions on the recording medium, color printing is easy, and high-speed printing can be performed relatively easily and with low noise. In order to eject ink droplets from the ink ejection nozzle, the ink ejection nozzle is communicated with an ink pressure chamber, and the wall of the ink pressure chamber is vibrated by electromechanical conversion means such as a piezoelectric element fixed thereto. It is made to let. That is, by applying a drive pulse voltage to such a piezoelectric element, a pressure wave is generated in the ink pressure chamber, whereby ink droplets are ejected from the ink ejection nozzle.

[0003] Ink jet heads have a problem of stopping ink jetting due to clogging of ink jet nozzles. Of course, if clogging occurs even in one of the ink jet nozzles of the ink jet head, proper printing becomes impossible. In order to cope with such a problem of clogging of the ink jet nozzles, conventionally, measures have been taken such as providing a clogging recovery mechanism in the ink jet printer, or disposing the ink jet head freely and disposing it. The micro kick system has been proposed to further improve the latter measure. More specifically, in the micro kick system, the ink ejecting unit and the vibration driving unit are configured to be separated. The ink ejecting section is composed of an ink container that forms an ink pressure chamber. An ink ejecting nozzle is formed in this container, and a part of the wall portion is a diaphragm. On the other hand, the vibration drive unit includes a drive pin that is brought into contact with the vibration plate of the ink container, and the drive pin is driven in a manner similar to the wire drive system of a conventional wire dot printer. In the micro-kick type ink jet printer having such a configuration, when the ink ejecting nozzle is clogged, only the ink container is disposable, so that there is an effect that the running cost is relatively small. In the wire driving method of the conventional wire dot printer, the driving stroke of the wire is 0.8 mm
However, in the micro kick system, since the driving stroke of the driving pin is about 1 μm, the noise at the time of printing operation is significantly reduced as compared with a conventional wire dot printer.

[0004]

Problems to be Solved by the Invention Referring to FIG.
A schematic configuration of a conventional micro kick type ink jet head is shown, in which reference numeral 10 indicates an ink container forming an ink pressure chamber, and reference numeral 12 indicates a pressure wave generated in ink in the pressure chamber. Shows drive pins. The ink container 10 includes a cylindrical container body 14 and a diaphragm 16 that closes the cylindrical container body 14.
An ink jet nozzle 18 is formed at the center of the front end face of the cylindrical container body 14. The drive pin 12 is connected to the ink container 10.
The driving method is the same as the wire driving method of the conventional wire dot printer as described above. When the vibration plate 16 is vibrated by the drive pins 12, a pressure wave is generated in the ink in the ink container 10, whereby the ink droplets D are ejected from the ink ejection nozzles 18, and printing is performed. become. In this case, in order to generate a sufficient pressure wave in the ink in the ink container 10 to guarantee the ink ejection from the ink ejection nozzle, the diaphragm 16 must be sufficiently bent by the drive pin 12. For this reason, in the conventional micro kick type ink jet head, as shown in FIG. 5, the diameter of the diaphragm 16 is larger than the diameter of the drive pin 12.

Thus, in the conventional micro kick type ink jet head, when a large number of ink jet nozzles are arranged, the arrangement pitch is relatively large, and it is difficult to increase the print recording density. Becomes Of course, for example, by arranging a large number of ink jet nozzles and shifting the arrangement pitch of each row little by little, it is possible to perform print recording at high density, but in this case, the ink jet head itself becomes large. Another problem arises. Accordingly, it is an object of the present invention to provide a micro-kick ink jet head which can guarantee the ink ejection from the ink ejection nozzles and can arrange the ink ejection nozzles at a high density.

[0006]

According to the present invention, an ink container having an ink jet nozzle, a vibrating plate formed on a part of the ink container, and a drive pin for applying vibration to the vibrating plate are provided. The micro-kick type ink jet head includes an elastic body interposed between the ink container and the vibration plate.

[0007]

As is apparent from the above structure, in the micro kick type ink jet head according to the present invention, since the elastic body is interposed between the ink container and the diaphragm, the diaphragm is driven by the driving pins. When
The vibrating plate does not vibrate due to its own bending but vibrates due to elastic deformation of the elastic body.

[0008]

Next, an embodiment of the ink jet head according to the present invention will be described with reference to the accompanying drawings. FIG.
Referring to FIG. 1, there is schematically illustrated a principle configuration of a micro kick type ink jet head according to the present invention. In the figure, reference numeral 20 indicates an ink container forming an ink pressure chamber, and reference numeral 22 indicates the inside of the pressure chamber. 4 shows a drive pin that creates a pressure wave in the ink. The ink container 20 includes a cylindrical container main body 24 formed of a suitable material such as stainless steel, glass, ceramic, or hard synthetic resin;
A vibration plate 26 for closing the cylindrical container body 14 and a ring-shaped elastic body 28 interposed between the cylindrical container body 24 and the vibration plate 26 are provided. An ink jet nozzle 30 is formed. The diaphragm 26 can also be formed of a suitable material such as stainless steel, glass, ceramic, or hard synthetic resin, similarly to the cylindrical container body 14. The drive pin 22 is brought into contact with the vibration plate 26 of the ink container 20, and the drive method may be the same as the wire drive method of the conventional wire dot printer as described above, or may be a piezoelectric element. Or the like using electromechanical conversion means. When the vibration plate 26 is vibrated by the drive pin 12, the vibration plate 26 does not vibrate due to its own bending, but vibrates due to elastic deformation of the elastic body. At this time, a pressure wave is generated in the ink in the ink container 20. Thus, the ink droplets D are ejected from the ink ejection nozzles 30, and print recording is performed. Therefore, the diameter of the diaphragm 26 can be set independently of the diameter of the drive pin 22, and may be substantially the same as the diameter of the drive pin 22 as shown in FIG. Is also possible.

Referring to FIG. 2, there is schematically shown a multi-nozzle type micro-kick ink jet head to which the principle configuration of the present invention shown in FIG. 1 is applied. In FIG. 2, reference numeral 32 denotes a plurality (eight). The ink container having the ink pressure chambers 34 is shown, and the reference numeral 36 indicates the driving pins arranged corresponding to each of the ink pressure chambers 34. In the present embodiment, each ink pressure chamber 34 has a rectangular shape, and two ink pressure chambers 34 adjacent to each other are separated from each other by a common partition wall 38. Each ink pressure chamber 34
Are closed by a rectangular pressure plate 40, and an elastic body 42 is interposed therebetween. The ink container 32 has a plurality of ink ejection nozzles 44 arranged corresponding to the ink pressure chambers 34, and each ink ejection nozzle 44 is positioned at the center of the corresponding ink pressure chamber 34. The arrangement pitch of the drive pins 36 is also the same as the arrangement pitch of the ink ejection nozzles 44, and these drive pins 36 are driven in a manner similar to the wire drive system of a conventional wire dot printer. Although FIG. 2 shows only a single row of eight ink jet nozzles 44, the other ink jet nozzle row is actually provided, and the arrangement pitch of the ink jet nozzle rows is Same as the nozzle row, but shifted by half the array pitch.

Referring to FIG. 3, a micro-kick type ink jet head to which the ink container 33 shown in FIG. The ink-jet head 46 includes a driving unit 48 for driving the driving pins 36, and the driving unit 48 has the same configuration as the wire driving unit of a conventional wire dot printer. As is apparent from FIG. 3, the ink jet head 46 is illustrated in a state where it is incorporated in a printer. That is, the ink jet head 46 is mounted on a carriage 50, which is slidably supported on a guide bar 52, and is reciprocated on the guide bar 52 along a platen 54 during a printing operation. During the printing operation, the drive unit 48 is controlled in such a manner that the ink droplets ejected from each of the two rows of ink ejection nozzles coincide on the same straight line perpendicular to the moving direction of the inkjet head 46. Therefore, by selectively operating the 16 drive pins 36 based on the print data, characters, symbols, and the like are recorded on the recording paper P in a 16 × 16 dot matrix. As described above, since the two rows of ink ejection nozzles are arranged so as to be shifted from each other by a half pitch, the pitch of the recording ink dots is half the arrangement pitch of the ink ejection nozzles.

In the embodiment described above, an ethylene / vinyl acetate copolymer is used as the elastic body 42, which is melted by heat and applied along the opening edge of the ink container 42, and then the vibration plate 40 is adhered thereto. After this, the ethylene / vinyl acetate copolymer was cooled to room temperature, whereby the diaphragm 40 was fixed to the ink container 42. At this time, the thickness of the elastic body 42 was about 20 μm. The driving plate 40 was made of stainless steel (SUS 304). The diameter of the drive pin 36 is about 200 μm,
0 has a circular shape substantially corresponding to the diameter of the drive pin 36. In this case, the arrangement pitch of the ink ejection nozzles 44 is approximately
300 μm, which is about 約 of the conventional case shown in FIG. That is, according to the present embodiment, the arrangement density of the ink ejection nozzles 44 can be increased four times as compared with the conventional case. Other materials of the elastic body 42 include styrene-butadiene rubber, isoprene rubber,
Synthetic rubber such as chloroprene rubber, urethane rubber, silicone rubber, ethylene / acryl rubber, nitrile rubber, and natural rubber are exemplified. The thickness of the elastic body 42 is 0.5 μm
If less than the above, sufficient elastic effect cannot be obtained, and 20
It was found that when the thickness was set to 0 μm or more, high-density mounting was hindered. Therefore, the thickness of the elastic body should be appropriately selected from the range of 0.5 to 200 μm in consideration of the characteristics of the rubber material used. In the embodiment shown in FIG. 2, a wire driving method of a conventional wire dot printer is used to drive the driving pins 36. However, each driving pin 36 is provided with an electromechanical conversion means such as a piezoelectric element. It is also possible to apply and drive.

FIG. 4 shows a modification of the principle configuration of the present invention shown in FIG. 1. This modification is different from the first embodiment in that the elastic member 26 is not formed in a ring shape but is made of a plate material similar to the vibration plate 26. Except for this, it is the same as that shown in FIG. It should be apparent that the embodiment shown in FIG. 2 can be achieved based on the modification shown in FIG.

[0013]

As is apparent from the above description, in the micro-kick ink jet head according to the present invention, the vibration plate is not vibrated by its own bending, but by the elastic deformation of the elastic body. It is possible to reduce the arrangement pitch of the ejection nozzles, so that it is possible to reduce the size of the micro kick type inkjet head.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a principle configuration of a micro kick type ink jet head according to the present invention.

FIG. 2 is a schematic diagram showing one embodiment of a micro-kick ink jet head configured based on the principle configuration of FIG. 1;

FIG. 3 is a perspective view schematically showing a state in which the micro kick type ink jet head of FIG. 2 is incorporated in a printer.

FIG. 4 is a cross-sectional view showing a modification of the principle configuration shown in FIG.

FIG. 5 is a cross-sectional view illustrating a schematic configuration of a conventional micro-kick ink jet head.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Ink container 12 ... Driving pin 14 ... Cylindrical container main body 16 ... Vibrating plate 18 ... Ink ejection nozzle 20 ... Ink container 22 ... Driving pin 24 ... Cylindrical container main body 26 ... Vibrating plate 28 ... Ring-shaped elastic body 30 ... Ink ejection nozzle 32 ... Ink container 34 ... Ink pressure chamber 36 ... Drive pin 38 ... Partition wall 40 ... Vibration plate 42 ... Elastic body 44 ... Ink ejection nozzle 46 ... Micro kick type inkjet head 48 ... Drive unit 50 ... Carriage 52 ... Information bar 54 ... Platen

 ────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-3-133656 (JP, A) JP-A-57-140172 (JP, A) JP-A-3-211059 (JP, A)

Claims (5)

(57) [Claims] An ink container (20; 32) having an ink ejection nozzle (30; 44), a vibrating plate (26; 40) formed on a part of the ink container, and a vibrating plate And a drive pin (22; 36) for providing an elastic body (28; 36) between the ink container and the diaphragm.
42) A micro-kick ink jet head, wherein the ink jet head is interposed. 2. The micro-kick ink jet head according to claim 1, wherein said driving pins (22; 3)
A micro-kick ink jet head, wherein the cross-sectional dimension of 6) is substantially the same as or smaller than the dimension of the diaphragm (26; 40). 3. The micro kick type ink jet head according to claim 1, wherein the elastic body (2)
8; 42) is a rubber material selected from the group consisting of styrene / butadiene rubber, isoprene rubber, chloroprene rubber, urethane rubber, silicone rubber, ethylene / vinyl acetate copolymer, ethylene / acrylic rubber, nitrile rubber, and natural rubber A micro-kick ink jet head characterized by being formed. 4. The micro-kick ink jet head according to claim 1, wherein:
The thickness of the elastic body (28; 42) is 0.5 to 200 μm
A micro-kick ink jet head, characterized in that: 5. The micro-kick ink jet head according to claim 1, wherein:
The vibrating plate (26; 40) is the elastic body (28; 42).
A micro-kick ink jet head, which is fixed to the ink container (20; 32) by heating and melting.