JPH05208500A - Ink jet recorder - Google Patents

Abstract

PURPOSE:To obtain an electrostatic attraction-type multi-nozzle ink jet recorder simplified in structure at a low cost. CONSTITUTION:A first thin plate 202 provided with a plurality of ink delivery ports 204 and grooves 206 on the both side thereof is joined to a second thin plate 203 provided with a slit opening 207 larger than the ink delivery port 204 so that the ink delivery ports 204 are positioned on the center of the slit opening 207. This is joined to the front surface of a body member 201. A plurality of signal sources 209 are connected between a plurality of control electrodes 205 independently provided around the respective ink delivery ports 204 and a common electrode 208 provided around the slit opening 207. The respective ink delivery ports 204 are connected to an ink chamber 210.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-nozzle type ink jet recording apparatus for ejecting ink from minute openings to record characters and figures on an object to be recorded.

[0002]

2. Description of the Related Art Recently, a printer using an ink jet recording system has been widely used as a terminal device for personal computers and CAD. In this ink jet recording system, as an ink jet recording apparatus in which ink is ejected from a minute opening by utilizing an air flow and an electrostatic force, for example, JP-A-57-120452 and JP-A-5-120452 are available.
A configuration as described in Japanese Patent Publication No. 9-146860 is known. Hereinafter, a conventional inkjet recording device will be described with reference to FIG.

FIG. 4 is a schematic diagram showing a partial cross section of an ink jet recording apparatus. In FIG. 4, an air nozzle plate 102 made of an insulating material is attached to the tip surface of the outer wall of the body member 101, and an ink nozzle plate 103 made of an insulating material is attached to the tip surface of the inner wall. An air chamber 104 is formed between the outer wall and the inner wall of the body member 101, and an air flow path 105 communicating with the air chamber 104 is formed between the air nozzle plate 102 and the ink nozzle plate 103. In addition, the ink chamber 106 is provided inside the ink nozzle plate 103.
Are formed. An ink ejection port 107 is formed in the center of the ink nozzle plate 103, and the air nozzle plate 10
2 includes an air ejection port 10 facing the ink ejection port 107.
8 is formed. On the surface of the air nozzle plate 102,
The first electrode 109 is formed around the air ejection port 108, and the ink ejection port 1 is formed on the back surface of the ink nozzle plate 103.
A second electrode 114 is formed around 07. The air chamber 104 is provided with an air supply source 112 through an air supply pipe 110.
The ink chamber 106 communicates with the ink supply source 113 by the ink supply pipe 111. First electrode 1
09 and the second electrode 114 are connected to the signal source 115.

Next, the operation of the above structure will be described. The air from the air supply source 112 is supplied to the air chamber 1
14 is sent to the air flow path 10 while making a sharp bend.
5 as an air layer at a constant flow rate, and this air flows out from the air ejection port 108 while making a sharp bend near the air ejection port 108 and the ink ejection port 107. On the other hand, ink is supplied from the ink supply source 113 to the ink chamber 106, and the ink supply source 113 and the ink chamber 1 are driven by the air pressure sent from the air supply source 112.
A constant pressure is applied to the ink in 06. As a result, at the time of non-recording of the inkjet recording apparatus, the air pressure in the vicinity of the ink ejection port 107 caused by the air flow and the ink pressure in the ink ejection port 107 become substantially equal, and the meniscus of the ink generated at the ink ejection port 107 becomes stationary. Will be kept. Then, when a potential difference is generated by the voltage applied from the signal source 115 to the first electrode 109 and the second electrode 114, the meniscus of the ink generated in the ink ejection port 107 due to the electrostatic force due to this potential difference is changed to the air ejection port. It is stretched in the direction of 108. Air flow path 10 from ink ejection port 107 to air ejection port 108
In FIG. 5, the ink meniscus of the ink ejection port 107 is
When it is stretched for a certain length or more, it is rapidly accelerated and flows out from the air discharge port 108 and fly in the air flow.

[0005]

The ink jet recording apparatus using such an air flow and electrostatic force is driven by a relatively low voltage (500 V or less) in spite of using electrostatic force, and has a high responsiveness. Is excellent (10 to 20 kHz), and it is possible to form fine dots (20 to 30 μmφ).

However, there are some problems other than the recording characteristics. First of all, the air supply source 11
2. An air supply system including the air supply pipe 110 is necessary. Due to the existence of such an air supply system, the cost is surely increased accordingly. Furthermore, the reliability problem of the air supply system arises. That is,
The problem of dust existing in the supply air or the problem of constant air pressure corresponds to this. In order to respond to these, a method of using a filter or controlling air pressure by detecting air pressure and applying electrical feedback has been adopted, but as a result, the device becomes complicated and the cost is further increased. become.

Secondly, there is a problem in construction method. In the assembly, when the ink ejection port 107 and the air ejection port 108 are arranged on the coaxial concentric circle, it is necessary to keep the interval of the air flow paths 105 constant with high accuracy. This spacing is less than 100 μm,
High precision parallelism is required, and the variation must be within a few μm. This is because this interval greatly affects the air pressure in the vicinity of the ink ejection port 107. That is, as the distance increases, the air pressure in the vicinity of the ink ejection port 107 rises, approaches the pressure in the ink chamber 106, and the ink meniscus formed in the ink ejection port 107 is pushed out toward the air ejection port 108 side. The ink will not be held, and the ink ejection amount and responsiveness will decrease. On the contrary, if this interval becomes narrower,
The responsiveness also increases, but the ejection becomes unstable. Therefore, it is necessary to maintain an optimal air flow path interval that can balance these. Further, in the case of using multiple nozzles, it is necessary to assemble the nozzles so that the intervals of the air flow paths do not vary among the nozzles, and the ink ejection openings and the air ejection openings are accurately aligned, which further increases the difficulty.

In still another electrostatic suction type ink jet recording system, for example, a structure as shown in Japanese Patent Laid-Open No. 58-208062, a cross sectional area between the ink ejection opening and the electrode opening is wider than each opening. Since it is constituted by the space region of, it is extremely disadvantageous when the nozzles are arranged at high density in the multi-nozzle system. In addition, if minute dust or ink invades this space area, the state of the electric field will change, and as a result, the ejection state will become unstable,
It tends to be a problem in terms of reliability. Also, from the viewpoint of the stability of the recording characteristics, there are also difficulties in assembling such as aligning the ink ejection openings and the electrode openings and ensuring parallelism.

The present invention solves the problem caused by the presence of the air supply system in the conventional ink jet recording apparatus, and provides a low cost ink jet recording apparatus having a simple structure and easy assembly. With the goal.

[0010]

In order to achieve the above object, the present invention provides a first thin plate in which a plurality of ink ejection ports are linearly arranged and grooves are formed on both sides thereof, and each ink ejection port. A second thin plate having a slit opening having a width larger than that of the outlet and extending along the arrangement direction, and the first and second thin plates are joined so that the ink ejection port is located at the center of the slit opening, A signal source is connected between a control electrode independently provided around each ink ejection port and a common electrode provided around the slit opening, and each ink ejection port is connected to the ink chamber. is there.

[0011]

According to the present invention, by applying a signal voltage between both electrodes, the ink meniscus formed at each ink ejection port is stretched and the ink is ejected to the outside through the slit openings. It is possible to record, and since the electric field strength can be increased by the two grooves formed on both sides of each ink ejection port, it is a low-cost multi-nozzle type with a simple structure, easy assembly, and stable characteristics. An inkjet recording device can be realized.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. 1 is a partial cross-sectional schematic perspective view of an ink jet recording apparatus according to an embodiment of the present invention, and FIG. 2 is a cross-sectional end view of FIG. In FIGS. 1 and 2, 20
Reference numeral 1 is a box-shaped body member, 202 is a first thin plate joined to an opening surface of the body member 201, and 203 is a first thin plate 20.
2 is a second thin plate joined to the front surface of the two, and these are made of an insulating material. A plurality of ink ejection ports 204 are linearly arranged on the first thin plate 202, and a plurality of independent control electrodes 205 are formed around each ink ejection port 204 on the back side thereof. Further, two grooves 206 are formed on both sides of each ink ejection port 204 on the front side of the first thin plate 202 along the arrangement direction.
On the other hand, in the second thin plate 203, a slit opening 2 having a width substantially equal to the outer dimension between the two grooves 206 of the first thin plate 202 and extending along the arrangement direction of each ink ejection port 204.
No. 07 is formed and is joined to the front side of the first thin plate 202 so that each ink ejection port 204 is located at the center of the slit opening 207. In addition, the second thin plate 20
A common electrode 208 is formed on the entire surface of the third plate 3, and a signal source 209 is connected between each control electrode 205 of the first thin plate 202 and the common electrode 208 of the second thin plate 203. .. A plurality of signal sources 209 are connected between the two electrodes 205 and 208 corresponding to each control electrode 205. The ink chamber 210 formed by the body member 201 and the first thin plate 202 is filled with ink, and a relatively short distance (2
The recording paper 211 is arranged in (mm or less).

The diameter of each ink ejection port 204 is several tens of μm, and the size of the slit opening 207 is such that the width thereof is the ink ejection port 2.
It is set to about 2 to 10 times the diameter of 04. Groove 206
Depth L is L / φ with respect to the diameter φ of the ink ejection port 204.
Is set to 0.2 or more. This is because when this ratio L / φ is 0.2 or more, as shown in FIG.
This is because the response frequency becomes constant, and by forming the groove 206, the front end of each ink ejection port 24 projects and the electric field strength concentrates. The stabilization of the characteristics due to the protrusion of the ink ejection ports 24 can be formed by surrounding each of the ink ejection ports 24 in an annular shape.
Is easier to process.

Next, the operation of the above embodiment will be described. When a signal voltage is applied between the electrodes 205 and 208 from the signal source 209, the electric field is concentrated on the surface of the ink meniscus formed at the front edge of the ink ejection port 204, and the ink in the ink chamber 210 is drawn out by the electrostatic force. , Becomes a string and flies outward from the center of the slit opening 207 and adheres to the recording paper 211. At this time, the two grooves 206 provided on both sides of each ink ejection port 204 can concentrate the electric field strength and stabilize the characteristics. In addition, the drive voltage is 50 to 10 by the two grooves 206.
It can be lowered by 0V. If the distance between the recording paper 211 and the slit opening 207 is too large, the flying ink returns and is attracted and attached to the common electrode 208. Therefore, this distance must be narrowed as described above.

In this embodiment, the factors that determine the recording characteristics are the shapes of the ink ejection ports 204 and the slit openings 207, the thickness of the thin plates 202 and 203, or the relative dielectric constant.
Examples include physical properties of the ink. Sheets 202 and 20
As for the relative permittivity of 3, the effective range is about 1 to 8, and the smaller the value, the better the response and the lower the driving voltage. With regard to the physical properties of the ink, the specific resistance is important, and a stable stringing state is obtained in the range of 10 ⁴ to 10 ⁸ Ωcm.

By performing an ink-repellent coating process on the inner wall and the periphery of the slit opening 207 and the surface periphery of the ink ejection port 204, in addition to holding the ink meniscus at the front end edge of the ink ejection port 204, this part is made redundant. It also has the effect of not being stained with ink,
This is an effective means for stable ejection. However, the thin plate 202,
It goes without saying that if the material of 203 already has ink repellency such as Teflon, the ink repellency coating process is unnecessary.

The actual recording characteristics in this embodiment are shown in FIG.
Although the responsiveness is slightly inferior to the conventional example shown in (1), the structure is simple and the multi-nozzle can be easily formed, the assembling method can be simplified, and the cost is extremely advantageous.

[0018]

As described above, the present invention has the first thin plate in which a plurality of ink ejection ports are linearly arranged and grooves are formed on both sides thereof, and has a width larger than each ink ejection port. And a second thin plate having a slit opening extending along the arrangement direction, and the first and second thin plates are joined so that the ink ejection port is located at the center of the slit opening, and the second thin plate is provided around each ink ejection port. A signal source is connected between a control electrode that is independently provided and a common electrode that is provided around the slit opening, and each ink ejection port is connected to the ink chamber. By applying a voltage, the ink meniscus formed on each ink ejection port can be extended, and ink can be ejected to the outside through the slit opening for recording, and the ink can be formed on both sides of each ink ejection port. Book groove The strength it is possible to increase the,
It is possible to realize a low-cost multi-nozzle type ink jet recording apparatus that has a simple structure, is easy to assemble, and has stable characteristics, and its effect is great.

[Brief description of drawings]

FIG. 1 is a schematic perspective view of a partial cross section of an inkjet recording apparatus according to an embodiment of the present invention.

FIG. 2 is a sectional end view of FIG.

FIG. 3 is a characteristic diagram of an embodiment of the present invention.

FIG. 4 is a partial cross-sectional schematic configuration diagram of a conventional inkjet recording apparatus.

[Explanation of symbols]

 201 Body Member 202 First Thin Plate 203 Second Thin Plate 204 Ink Ejection Port 205 Control Electrode 206 Groove 207 Slit Opening 208 Common Electrode 209 Signal Source 210 Ink Chamber 211 Recording Paper

Claims (1)

[Claims] 1. A plurality of ink ejection ports are arranged in a straight line, and each control device has a plurality of control electrodes independently formed around each ink ejection port on the back side thereof, and each front side ink ejection port. 2 formed on both sides of the outlet along the arrangement direction
A first thin plate having two grooves, and a slit opening having a width substantially equal to the outer dimension between the two grooves and extending along the arrangement direction of each ink ejection port, and A second thin plate joined to the front side of the first thin plate so that each ink ejection port is located in the center, a common electrode formed on the surface of the second thin plate, and each control of the first thin plate An ink jet recording apparatus comprising: a plurality of signal sources connected to electrodes and a common electrode of a second thin plate; and an ink chamber provided in communication with the back side of each ink ejection port of the first thin plate.