JPH0327385B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an inkjet recording device that utilizes air flow and electrostatic force.

FIG. 1 shows an inkjet recording device using air flow and electrostatic force according to the applicant's earlier application. An insulating air nozzle plate 2 is provided with air discharge ports 1, and a conductive ink nozzle plate 3 is disposed in parallel with the nozzle plate 2. An ink discharge port 4 is bored opposite to the ink discharge port 1 .

An air flow flows into the air supply path 8 from an air supply source 20, is made uniform in an annular air chamber 9, and is distributed around the air layer 7 by the air nozzle plate 2 and the ink nozzle plate 3. The air flows in from the air outlet 1 and flows out from the air outlet 1. Since this air flow changes rapidly near the air outlet 1, a rapid change in pressure gradient occurs in the space from the ink outlet 4 to the air outlet 1.

On the other hand, the ink chamber 10 adjacent to the ink discharge port 4
is in communication with the ink reservoir 11 via the ink supply path 6, and the ink in the ink reservoir 11 is applied with a constant pressure adjusted by a pressure adjustment mechanism 21 using air pressure from an air supply source 20. has been done. This is because when the inkjet recording device is not driven, the air pressure near the ink ejection port 4 and the ink pressure in the ink ejection port 4 or the ink chamber 10 are approximately equal, and the meniscus of ink in the ink ejection port 4 is kept stationary. This is to make adjustments so that the

The signal source 5 is connected to an electrode 12 provided around the air outlet 1 and the ink nozzle plate 3, and a potential difference is generated between the electrode 12 and the ink outlet 4. Due to the electrostatic force caused by this potential difference, the meniscus of ink generated at the ink ejection port 4 is stretched in the direction of the air ejection port 1. Furthermore, since a sudden change in pressure gradient occurs in the space from the ink discharge port 4 to the air discharge port 1, if the ink meniscus generated at the ink discharge port 4 is stretched beyond a certain length, the pressure gradient changes. It is accelerated by the air and flies from the air outlet 1.

FIG. 2 shows a conventional example of a multi-nozzle inkjet recording device using air flow and electrostatic force, which is related to an earlier application filed by the present applicant.

In FIGS. 2a and 2b, an insulating air nozzle plate 201 has air outlets 101 to 106 perforated at equal intervals.
An independent electrode 121 on one side surface including the periphery of 06
~126 are provided. An ink nozzle plate 301 is installed parallel to the air nozzle plate 2,
Ink discharge ports 401 to 406 are bored opposite to the air discharge ports 101 to 106. The ink nozzle plate 301 and the body member 13 form a common ink chamber 1000, and the ink discharge port 40
1 to 406 and an ink supply path 60.
It communicates with the ink reservoir via 1. Further, an air flow flows into the air chamber 901 constituted by the air nozzle plate 201 and the body member 131 via the air supply chamber 801, and this air flow flows through the air nozzle plate 2
01 and the ink nozzle plate 301, and flows out from the air discharge ports 101 to 106 with sharp bends. On the other hand, a constant pressure is applied to the ink in the ink chamber 1000, and the pressure is adjusted so that the meniscus of the ink is stably maintained at each of the ink ejection ports 401 to 406 when the inkjet recording apparatus is not driven.

The electrodes 121 to 126 are connected to signal sources 501 to 126, respectively.
506, and the signal sources 501 to 506
It can be generated independently between the ink nozzle plate 301 and the ink nozzle plate 301 commonly connected to the ink nozzle plate 301. electrode 12
When a potential difference is generated between the ink nozzle plates 301 of 1 to 126, as is clear from the explanation in FIG.
Ink liquid is discharged from 406 and air discharge port 101
~ Fly through 106. Although the number of ink ejection ports shown in FIG. 2 is six, it is possible to
Of course, this is also possible in the case of 3) ink ejection ports, and since the ejection of ink liquid from each ink ejection port can be controlled independently, it is possible to create recorded matter at n times the speed. .

However, in the inkjet recording apparatus as shown in FIGS. 2a and 2b, the air discharge port 101
106 and the ink ejection ports 401 to 406 must be aligned concentrically, the air ejection ports 1
01-106 or ink discharge ports 401-40
There are difficulties in that the perforation position accuracy of 6 is required and the assembly resistance accuracy is strictly required.
6, it is difficult to arrange the divided electrodes 121 to 126 with good insulation and high density, resulting in undesirable phenomena such as electric discharge.

The present invention has been made to eliminate these drawbacks, and employs a structure in which the ink discharge port is a slit-shaped opening that is continuous in the direction in which the air discharge ports are arranged, and an electrode is installed on the back side of this opening. This is what I did. A detailed explanation will be given below according to examples.

Figures 3a and 3b show an embodiment of the present invention. Third
In the figure, an electrode 1200 provided on the air nozzle plate 201' is connected to each air outlet 101' to 101'.
8', and that the ink ejection ports are slits 14 formed in the nozzle plate 301' and open continuously in the arrangement direction of the air ejection ports 101' to 108'. The slit 14 faces the air outlets 101' to 108', and electrodes 151 to 158 are installed on the surface of the slit 14 on the ink chamber 1000' side, corresponding to the air outlets 101' to 108', respectively. It differs from Fig. 2 in that it is Note that illustration of the signal source is omitted.

In FIG. 3, electrodes 151 to 158 and electrode 120
By providing a potential difference between
Stretched in the 8' direction, due to the action of the air flow,
It flies from the air discharge ports 101' to 108'. The meniscus of the ink generated within the slit 14 is formed in a continuous shape within the slit 14, but fluctuations in the meniscus occur at locations where electrostatic force is concentrated (electrode 15).
1 to 158), and the position of the change is adjacent to a space where the airflow is rapidly bending and the pressure gradient is rapidly changing. 101'~10
It is independently controlled from 8' and flies.

In a multi-nozzle inkjet recording device having such a structure, the ink ejection port is connected to the air ejection port 1.
Since the slits 14 are continuously expanded in the arrangement direction of 01' to 108', air discharge ports 101' to 108'
The drilling position of 108' does not require much precision,
Furthermore, positioning can be easily performed during the assembly process, and advanced technology or skill is not required.

FIG. 4 is an enlarged exploded perspective view of the main part of the configuration shown in FIG. 3. In the figure, the same parts as in FIG. 3 are given the same reference numerals. An electrode 12 is placed on the surface of the air nozzle plate 201'.
00 is provided and the signal sources 501', 502', 50
3'..., and independent electrodes 151, 15 are connected to the back surface of the ink nozzle plate 301'.
2,153... are provided, and each signal source 501',
502', 503'... are independently and separately connected. The principle of operation has already been explained in FIG. 3, so it is omitted here. Electrode 15 provided on the ink nozzle plate 301' side as shown in FIG.
In the method of dividing 1,152,153..., the electrode shapes are air discharge ports 101', 102', 103'...
It is possible to increase the density because it is not restricted by the shape of... In this case, if the electrode spacing is minute and the electrodes are exposed to the air, undesirable phenomena such as discharge may occur and the electrodes may be destroyed, but in the embodiment shown in FIG. By using an insulating ink such as an oil-based ink having a specific resistance of about 10 ⁶ Ωcm or more, the electrodes are protected by the insulating properties of the ink, and a highly durable inkjet recording device can be realized.

FIG. 5 shows another embodiment of the electrode portion in the configuration of FIG. 4. Components in the figure that are the same as those in FIG. 4 are designated by the same reference numerals, and their explanation will be omitted. What is different from FIG. 4 is the electrodes 151', 152', 15 formed on the ink chamber side of the ink nozzle plate 301'.
3' is a continuous portion without being cut at the slit 142, and the other portions are exactly the same as in FIG. 4. In this case, the ink is applied to the electrodes 151', 15
2', 153'... are supplied to the slit 142 from both sides. The operation is performed in exactly the same manner as shown in FIGS. 3 and 4.

FIG. 6 is an enlarged perspective view of the main parts of another embodiment of the inkjet recording apparatus according to the present invention.

FIG. 6 shows an embodiment that differs from FIG. 3 with respect to the arrangement of the electrodes. The air nozzle plate 201' made of an insulating material has air discharge ports 101', 102', 10.
3'... are perforated at equal intervals, and electrodes 121, 122, 123 are provided independently on the peripheral surfaces of the air discharge ports 101', 102', 103'.
. . are independently connected to signal sources 501', 502', 503', . Air nozzle plate 20
1', electrodes 121, 122, 123...
An ink nozzle plate 301' forming a slit 142 is installed on the opposite side. An electrode 150 is installed on the back surface of the ink nozzle plate 301' and is commonly connected to the signal sources 501', 502', 503', . In addition, the air nozzle plate 20
1' and the ink nozzle plate 301' form an air layer, and the air flow flowing into the air layer flows through the air discharge ports 101', 102', 10
3'... Each of them makes a sharp bend and flows out.

In FIG. 6, electrodes 121, 122, 12
Since a potential difference is generated independently between the air outlet ports 101', 102', and the electrode 150,
The ink menisci formed in the slits 142 closest to the air outlets 101', 102', 103' are varied independently.
...The ink liquid can be ejected and flying. Also in FIG. 6, air discharge ports 101', 1
02', 103', . . . are not required to have perforation positional accuracy, and no advanced technology or skill is required in the assembly process.

Note that the ink ejection ports may be any openings that extend continuously in the direction in which the air ejection ports are arranged, and are not limited to slits.

As described in detail above, the present invention provides an inkjet recording device that utilizes air flow and electrostatic force, in which the ink ejection ports are continuously expanded in the direction in which the air ejection ports are arranged. An electrode is provided on the back surface (on the ink chamber side), and a multi-nozzle inkjet recording device with a simple manufacturing process and high density can be provided.

[Brief explanation of the drawing]

FIG. 1 is a partially sectional side view showing the configuration of an inkjet recording device according to the applicant's earlier application, and FIG.
Figures a and b are a cross-sectional side view and a plan view showing another example of the inkjet recording device according to the applicant's earlier application, and Figures 3a and b are cross-sectional side views showing an embodiment of the inkjet recording device according to the present invention. 4 is an enlarged perspective view of the air discharge port and ink discharge port in the embodiment shown in FIG. 3, and FIG. 5 is an enlarged perspective view of the air discharge port and ink discharge port in the embodiment shown in FIG. FIG. 6 is an enlarged perspective view showing another embodiment of the air discharge port section and the ink discharge port section of the inkjet recording apparatus according to the present invention. 1,101-106,101'-108'...Air discharge port, 2,201,201'...Air nozzle plate, 3,301,302...Ink nozzle plate,
4,401-406...Ink discharge port, 5,50
1 to 506, 501' to 503'...signal source, 6,
601,601'...Ink supply path, 7...Air layer, 8,801,801'...Air supply path, 9,
901,901'...air chamber, 10,1000,
1000'...ink chamber, 11...ink reservoir,
12,121-126,1200...electrode, 1
3,131,131'...Body, 14,142
...Slit, 1500, 151-158... Electrode.

Claims (1)

[Scope of Claims] 1. A plate member having a plurality of air discharge ports arranged therein, and an ink discharge port continuously expanding in the direction in which the air discharge ports are arranged, and disposed adjacent to an ink chamber storing oil-based ink. The plate members are placed facing each other at a constant distance, and the air flow is sent out from the air outlet while creating a sharp bend in the part between the ink outlet and the air outlet. a first means for forming a space in which the pressure gradient changes such that the air pressure decreases in the direction leading to the outlet;
and second means for selectively creating a potential difference in response to a signal between the member in which the air discharge port is formed and the electrode installed on the surface of the plate member having the ink discharge port adjacent to the ink chamber. , the meniscus of the ink generated in the ink ejection port is stretched by the attractive force caused by the potential difference of the second means, and the accelerating force of the air flow generated in the space where the pressure gradient changes is applied by the first means, and the inside of the ink ejection port is An inkjet recording device characterized in that ink is ejected outward through an air ejection port. 2. The inkjet recording device according to claim 1, wherein electrodes are separately installed on a plate member having ink ejection ports, and each electrode generates a potential difference independently.