JPS59138463A - Liquid jet recording apparatus - Google Patents

Abstract

PURPOSE:To perform high quality image recording by reducing irregularity in the flight of liquid droplets between emitting orifices, by specifying the cross- sectional area of each of liquid supply ports provided in a ratio of at least one or more per 100 emitting orifices. CONSTITUTION:When the numbers of the supply port 108 which are provided to a substrate 101 by drilling and connect a first liquid chamber 110 and a second liquid chamber 119 is provided in a ratio of less than one per 100 emitting ports 108, if the size of each supply port 118 is sufficiently large, large difference is generated in the frequency limit between the orifices by the difference of a place where the orifice is positioned. In order to reduce this emitting irregularity between the orifices, the supply port is pref. provided in a ratio of one or more per 32 orifices. In addition, the cross-sectional area Sh of the supply port 118 is set to the size satisfying the formula. The length Ln of a liquid flowline 21 means the distance from the boundary of the common liquid chamber part of the first liquid chamber and the liquid flowline to the center of the orifice 108.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a liquid jet recording device that performs recording using flying droplets formed by discharging liquid from a discharge port, and particularly relates to a liquid jet recording device that uses thermal energy. .

There are various types of liquid jet recording devices, and one of them, for example, is the liquid jet recording device disclosed in Japanese Laid-Open Publication No. 2844-05 (ILS), which can easily perform high-speed color recording and has a large output section. The recording head, which is the main part, has a high density array of ejection ports (orifices) for ejecting recording liquid and forming rigid droplets, so it has high resolution and high power. At the same time you can get
As a recording head, it can be made compact overall and suitable for mass production, and furthermore, it takes full advantage of the advantages of IC technology and micro-processing technology, which are rapidly improving in technology and reliability in the semiconductor field. Recently, it has been attracting a lot of attention because it is easy to make it long and planar (two-dimensional).

However, in the case of a conventional recording head of the multi-orifice type, a liquid flow path is provided corresponding to each orifice, and thermal energy is applied to the liquid filling the liquid flow path for each liquid flow path to open the corresponding orifice. Discharge more liquid,
An electrothermal converter is provided as a means for forming flying liquid, and each liquid flow path is configured to be supplied with liquid from a common liquid chamber communicating with each liquid flow path. The common liquid chamber is
Because it is necessary to arrange the recording paper above it, and because it is necessary to arrange the electrothermal converter below it, it is not possible to install it in a sufficiently large space. In such a case, if a structure in which several hundred or more orifices are densely arranged is used, the amount of liquid used will increase significantly compared to the size of the common liquid chamber, and furthermore, each of the above-mentioned problems will occur. Due to reasons such as the liquid flow path becoming narrower and the liquid flow path wall resistance increasing, the liquid supply (refi) is required during high-speed recording.
ll) could no longer be followed, and droplet formation became unstable, resulting in a problem that high-quality images could not be recorded at high speed.

One way to solve this liquid supply problem when performing high-speed recording is to install a second liquid that stores liquid for replenishing the common liquid chamber below the electrothermal converter at the bottom of the common liquid chamber. It has been considered to arrange chambers and provide a supply port connecting these liquid chambers in the installation gap of the electrothermal converter. However, the actual situation is that depending on how the supply ports are installed, the liquid supply to the orifices may still not be able to keep up, or that there may be large differences in the frequency limits between the orifices due to differences in the locations of the orifices.

The present invention has been made in view of the above points, and its main object is to provide a liquid jet recording device that can faithfully perform high-density and high-speed recording.

Another object of the present invention is to provide a liquid jet recording device that has little variation in droplet flight between ejection ports and is suitable for high-quality image recording.

The liquid jet recording device of the present invention includes a plurality of ejection ports provided for ejecting liquid to form flying droplets by using thermal energy, and a plurality of ejection ports communicating with these ejection ports to form flying droplets. a first liquid chamber to which a liquid is supplied for forming the
a second liquid chamber provided at a lower part of the first liquid chamber for storing a liquid for replenishing the liquid to the first liquid chamber through a supply port; and a second liquid chamber provided corresponding to each of the discharge port. The invention further includes a plurality of electrothermal converters serving as means for generating the thermal energy, each of which has a heat action surface as a surface on which the generated thermal energy acts on the liquid. The discharge ports are provided on the bottom surface of the first liquid chamber, and each of the discharge ports is provided facing each other on the bottom surface. In the liquid jet recording device, the supply port is provided at a ratio of at least one per 100 ejection ports, and the supply port is provided at a ratio of at least one per 100 ejection ports, and the supply port is provided at a ratio of at least one per 100 ejection ports, and The cross-sectional area sh (however, S
n is the cross-sectional area of one liquid flow path, Nn is the total number of discharge ports, L
(n is the length of the liquid flow path, Nh is the total number of supply ports, and Lh is the length of the supply ports).

The liquid jet recording device of the present invention having the above configuration exhibits excellent performance with excellent response fidelity, reliability, and performance to high-frequency recording signals, and little variation in droplet flight between orifices. .

Hereinafter, the present invention will be explained in more detail with reference to the drawings.

1 to 3 are diagrams showing an outline of a liquid jet recording device according to the present invention, with FIG. 1 being a schematic exploded view for explaining the internal structure, and FIG. 2 being a schematic plan view thereof. 3 are cross-sectional views taken along the dashed line AB in FIG. 2.

The liquid jet recording apparatus 100 shown in FIGS. 1 to 3 includes a substrate 101, an electric converter 102 provided on the substrate 101, a front wall plate 103 for forming a first liquid chamber +10, Rear wall plate 105 and these wall plates 103,1
05, and an orifice plate 107 provided with a through hole 109 constituting an orifice 108 provided corresponding to each electrical converter, and an orifice plate 107 that isolates adjacent orifices 108 from each other. A separation wall 11 provided in the first liquid chamber 110 that forms a liquid flow path 121 for each orifice. a second liquid chamber 119 provided at the bottom of the substrate 101 that stores liquid for replenishing the first liquid chamber through a supply port 118 drilled in the substrate 101; 119 and a supply pipe 120 for supplying liquid.

The electric converter 102 includes a heating resistance layer 111 on a substrate 101-L, and a selection electrode 1 provided in parallel on the heating resistance layer 111 except for a part of the heating resistance layer 111, in order from the substrate side.
12. A protective layer 113 provided at least on the common electrode 114 and the portion that directly contacts the liquid in the liquid chamber 110.
It consists of

When the heat generating resistive layer 111 is energized through the selection electrode 112 and the common electrode 114, it mainly generates thermal energy in the heat generating portion 11B between these electrodes. The heat acting surface 115 is where the generated heat acts on the liquid, and has a close relationship with the heat generating portion 11B. This heat action surface 1
Bubbles are generated in the liquid due to the thermal action at 15, and the pressure energy of the bubbles causes the liquid to be ejected from the orifice 168 in the form of flying droplets, thereby performing recording.

In order to drive each of the electric transducers 102 in accordance with a recording signal to eject a droplet from a predetermined orifice 108, a signal voltage is supplied through the selected selection electrode 112 and the common electrode 114 as described in the embodiments above. In the structure of the liquid jet recording device, in the present invention, at least one supply port 118 is provided for every 100 orifices, and the cross-sectional area s of the supply port 118 is
h is provided as having a specified size.

That is, when the number of supply ports 118 connecting the first liquid chamber 110 and the second liquid chamber 118 drilled in the substrate +01 is provided at a ratio of less than one per 100 discharge ports,
Even if the supply port 118 is of sufficient size, the difference in the location of the orifice will cause a large difference in the frequency limit between the orifices. In order to further reduce the variation in discharge between the orifices, it is more preferable that one or more orifices are provided for every 32 orifices.

It is necessary that the cross-sectional area sh of the supply port 11B has a size that satisfies equation (1). Note that the length Ln of the liquid flow path 121 here does not refer to the entire length of the liquid flow path formed by the separation wall 117, but rather refers to the common liquid chamber portion of the first liquid chamber as shown in FIG. is the distance from the boundary of the liquid flow path to the center of the orifice 108. If the cross-sectional area sh of the supply port 118 is smaller than the value determined by the above formula (1), no matter how many supply ports are provided, if high frequency recording is attempted, the liquid ejection from the orifice will be affected. However, this is not appropriate because the liquid supply may not be able to follow it.

FIG. 4 is a schematic diagram showing a preferred modification of the installation style of the first liquid chamber 110 and the supply pipe 120 in the liquid jet recording device of the present invention. The number of installed supply ports 118 and the cross-sectional area sh must satisfy the above-mentioned requirements.

Hereinafter, the present invention will be explained in more detail according to Examples.

Example 1 On a Si substrate whose surface was thermally oxidized to form a 5iOz layer three times thick, a Ta layer with a thickness of 200OA as a heating resistance layer and 41 layers as electrodes with a thickness of 1μ was laminated, and then the shape was 30μX 150JLll by a photolithography process. 128 heat generating part (heater) arrays were formed at a pitch of 8 wood/l. In addition, the oxidation prevention of the Ta layer and the penetration prevention of ink liquid +h,
5102 layer 0.5μ thick, as a membrane for mechanical impact resistance caused by bubbles generated when liquid receives thermal energy.
A protective layer was formed by sequentially stacking SiC layers IJLII+ thick by sputtering. On this substrate, a cross-sectional area of 7.
I X 10' m+i2 (pore diameter is aoop) length 0
．． Three ink supply holes of 50+m were provided. The holes were arranged at 4 mm intervals from the side surface of the first liquid chamber at positions 1IIllAl apart from the portion where the liquid flow path was provided.

Next, a separation wall, a front wall plate, a rear wall plate, two side wall plates, an orifice plate, a second liquid chamber, and a supply pipe are installed on this substrate-L as shown in Figures 1 to 3, and liquid injection is recorded. The device was created. Cross-sectional area of liquid flow path partitioned by separating wall, S X 1
0' +*m2. The length was lllll11, and a total of 128 orifices were installed. In addition, the value of (bn:nh)” @ Sn in this example is 7.4
It is X 10103a.

When the liquid jet recording device created in this way was operated under the following conditions, the results were as follows: when a droplet was ejected from only one orifice, and when the same droplet was ejected from all 128 orifices. With.

Its discharge frequency limit was the same, 8 KHz. Further, no difference was observed in the ejection characteristics of droplets from the orifices near both ends of the head and the one orifice in the center, and there was no difference in the ejection state due to the difference in the position of the orifice.

[Liquid jet recording device driving conditions]

Applied voltage: 27 volts Pulse width = lO sea Frequency: 0.5 to 10 KHz rib, Modified Examples 2 to 4 and Comparative Examples 1 to 3 In the liquid jet recording device of Example 1, the cross-sectional area of the supply r1 was A liquid jet recording device that was completely the same except for the changes was made, and a discharge characteristic test was conducted under the same conditions as in Example 1, and the results shown in Table 1 were obtained.

Examples 5 to 16 In the liquid jet recording device of Example 1 or the liquid jet recording device having the cross-sectional structure shown in FIG. 4, the size of each part determining the structure was changed as shown in Table 2. . However, H
n represents the height of the liquid flow path, and He represents the height of the first liquid chamber. When these liquid jet recording devices were used to test the ejection characteristics of Example 2 in the same manner as in Example 1, good results were obtained in all cases, just like in Example 1.

[Brief explanation of the drawing]

1 to 3 are diagrams showing an outline of a liquid jet recording device according to the present invention, in which FIG. 1 is a schematic exploded view, FIG. 2 is a schematic plan view thereof, and FIG. FIG. 2 is a sectional view taken along the dashed line AB in FIG. 2; FIG. 4 is a schematic sectional view showing a preferred modification of the liquid jet recording apparatus of the present invention. 100: Liquid jet recording device 101: Substrate 102: Electric converter 103: Front wall plate 104: Side wall plate 105: Rear wall plate
106: Supply pipe 107: Orifice plate 108 Niorifice 108: Through hole 110: First liquid chamber 111
: Heat generating resistance layer 112 : Selection electrode 113 : Protective layer
114: Common electrode 115: Heat action surface 1
16: Heat generating part 117: Space ax 118:
Supply Q B 118: Second liquid chamber 120: Supply pipe 1
21: Liquid flow path 0-

Claims (1)

[Claims] 1. A plurality of ejection ports provided for ejecting liquid to form flying droplets by using thermal energy, and a liquid communicating with these ejection ports to form the flying droplets. a first liquid chamber to be supplied; a second liquid chamber provided at a lower part of the first liquid chamber for storing a liquid for replenishing the liquid to the first liquid chamber through a supply port; and a second liquid chamber provided at a lower part of the first liquid chamber, and the discharge port. and a plurality of electrothermal converters serving as means for generating the thermal energy, each of which is provided corresponding to each of the plurality of electrothermal converters, and each of the electrothermal converters is configured such that the generated thermal energy acts on the liquid. The first liquid chamber has a heat acting surface as a surface on the bottom surface of the first liquid chamber, and each of the discharge ports is provided facing each other on the bottom surface and isolates adjacent heat acting surfaces and discharge ports. In a liquid jet recording device in which a separation wall is provided in the first liquid chamber and has a liquid flow path for each ejection port, the supply port is provided at a ratio of at least one per 100 ejection ports. and the cross section of the supply port (where Sn is the cross-sectional area of one liquid flow path, Nn is the total number of discharge ports, Ln is the length of the liquid flow path, Nh is the total number of supply ports, A liquid jet recording device characterized by having a size that satisfies equation (1) (indicating the length of an Lh supply port).