JPH0457500B2 - - Google Patents

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 to a liquid jet recording device that uses thermal energy. There are various types of liquid jet recording devices, but
Among them, for example, the German Open Gazette (OLS)
The liquid jet recording device disclosed in Publication No. 2944005 is
High-speed color recording is easy, and the recording head, which is the main part of the output section, has ejection ports (orifices) arranged in high density for ejecting recording liquid and forming flying droplets. In order to be able to
At the same time, it is possible to obtain high resolution, and at the same time, it is possible to make the recording head more compact and suitable for mass production.Furthermore, in the semiconductor field, technological advances and reliability improvements are remarkable, such as IC technology and microprocessing technology. Recently, it has been attracting a lot of attention because it is easy to make it long and planar (two-dimensional) by making full use of its advantages. 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 create a corresponding orifice. An electrothermal converter is provided as a means for ejecting liquid to form flying liquid, and each liquid flow path is supplied with liquid from a common liquid chamber communicating with each liquid flow path. Therefore, if the orifices are arranged in a high-density structure, each liquid flow path will inevitably become narrower and the wall resistance of the liquid flow path will increase.During high-speed recording, the liquid supply (refill) A problem arose in that the droplet formation became unstable, making it impossible to record high-quality images at high speed. One way to solve this problem of liquid supply when performing high-speed recording is to remove the liquid flow path walls between each liquid flow path so that the liquid supply can be performed quickly and smoothly. As a room,
Studies are underway to design a liquid supply path so that a sufficient amount of liquid can be quickly and smoothly supplied to the liquid chamber. However, in this case, since there is no separation wall between adjacent electrothermal converters, interaction occurs in liquid discharge between adjacent orifices, and liquid cannot be discharged independently from each orifice. It becomes difficult. In other words, for example, if electrothermal transducers corresponding to adjacent orifices are driven independently, liquid will be discharged from the orifice corresponding to the electrothermal transducer that is turned on, and at the same time, the electrothermal transducer that is in the OFF state will discharge liquid. Even if the liquid is ejected more than the corresponding orifice, or even if the liquid is not completely ejected, the meniscus moves or vibrates, causing an interference effect that adversely affects the stable liquid ejection of the adjacent orifice. Therefore, if there is such an interference effect, the discharge state of the liquid discharged from each orifice will become unstable.
In many cases, the flying speed, flying direction, droplet diameter, etc. of the formed droplets are not stable, making it impossible to record a high quality image. This becomes an extremely serious problem as the amount of thermal energy generated by the electrothermal converter increases when high-quality images are recorded at high speed by arranging orifices at high density. . The present invention has been made in view of the above points, and a main object of the present invention is to provide a liquid jet recording device that can easily perform high-density and high-speed recording. Another object of the present invention is to provide a liquid jet recording device suitable for recording high quality images. The liquid jet recording device of the present invention has 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 liquid chamber to which a liquid for forming droplets is supplied, a supply port for supplying the liquid to the liquid chamber, and means for generating the thermal energy, which are provided corresponding to each of the discharges. a plurality of electrothermal converters, each of which has a heat acting surface on which generated thermal energy acts on the liquid, the bottom surface of the liquid chamber, and a bottom surface of the liquid chamber; In each of the liquid jet recording devices provided opposite to each other on the bottom surface, a separation wall provided in the liquid chamber that isolates the adjacent heat acting surfaces and the ejection ports, respectively, When Lmin is the minimum distance between the heat acting surfaces measured without penetrating the wall, and Doh is the distance between the heat acting surfaces and the center of the corresponding discharge port, 1≦Lmin/Doh≦ It is characterized by being installed to satisfy a relational expression of 500. The liquid jet recording apparatus of the present invention having the above configuration has excellent fidelity and reliability of response to recording signals, and can record high-resolution, high-quality images at high speed. Hereinafter, the present invention will be explained in more detail with reference to the drawings. 1 to 3 are diagrams showing an outline of the liquid jet recording device according to the present invention, in which FIG. 1 is a schematic perspective view, and FIG. 2 is a diagram taken along the dashed-dotted line AB in FIG. 1. FIG. 3 is a schematic exploded view for explaining the internal structure. The liquid jet recording apparatus 100 shown in FIGS. 1 to 3 includes a substrate 101, and n electrical transducers 102 (in the figure, a first, a second, and an n-th electrical converter) provided on the substrate 101. (the second electrical transducer is shown) and a liquid chamber 110 for forming the liquid chamber 110.
Front wall board 103, rear wall board 105, and these wall boards 1
The two side wall plates 104-1 and 104-2 (one of the side wall plates is not visible in Fig. 1, but a part of it is visible in Fig. 3) held at both ends by the 03 and 105, and each electric An orifice plate 107 provided with a through hole 109 constituting an orifice 108 provided corresponding to the heat converter and a liquid chamber 110 attached to the rear side of the side wall plate 104-1 are provided for supplying liquid. It is mainly composed of a supply pipe 106. The electrothermal converter 102 includes a heating resistance layer 111, a selection electrode 112, and a common electrode 114, which are 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 on the substrate 101. , and a protective layer 113 provided at least in a portion that directly contacts the liquid in the liquid chamber 110. 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 116 between these electrodes. The heat acting surface 115 is a place where the generated heat acts on the liquid, and is closely related to the heat generating part 116. A valve is generated in the liquid due to the heat action on the heat action surface 115, and the pressure energy causes the liquid to be ejected from the orifice 108 as a flying droplet, thereby performing recording. Driving each of the electrical transducers 102 in accordance with a recording signal to eject a droplet from a predetermined orifice 108 is performed by supplying a signal voltage through a selected selection electrode 112 and a common electrode 114. be done. In addition to the configuration of the conventional liquid jet recording device described above, in the liquid jet recording device of the present invention, a separation wall 117 having a specified configuration that isolates the adjacent heat acting surfaces 115 and the orifice 108, respectively. is provided. This separation wall 117 has the problems of the individual liquid flow path method in which liquid flow paths are provided corresponding to each orifice as described above.
In other words, the tracking characteristics at high frequencies are poor due to the slow liquid supply, and the problems with the large liquid chamber individual system.
That is, the separation wall is provided to simultaneously solve both of the problems of liquid discharge interference occurring between adjacent orifices, and for this purpose, the separation wall must be configured to satisfy the relational expression described in detail below. That is, Lmin is the minimum distance between the heat-active surfaces measured without penetrating the separating wall, and the distance between the heat-active surface and the center of the corresponding orifice is Lmin.
When Doh is set, it must be installed so that the relational expression 1≦Lmin/Doh≦500 is satisfied. In order to clarify the meaning of the above relational expression of the present invention, FIGS. These will be explained in more detail using FIG. 5, which is a cutaway view taken along the dashed line XY. The heat action surface 115 refers to the part of the heat generating section 116 projected vertically upward onto the bottom surface of the liquid chamber, and the distance between the heat action surfaces is indicated by L ₀ , but the heat action surface 115 is the part where the heat action is measured without penetrating the separation wall 117. The distance between surfaces is a distance measured by bypassing the separation wall 117, such as _L1 and _L2 , and the shortest value among these many measured distances is taken as Lmin. On the other hand, the distance Doh between the heat acting surface and the center of the corresponding thermal energy generally takes a constant value for each heat acting surface and orifice, as shown in Figure 5, but if this value is not constant. In this case, Doh is the shortest value among the measured distances. Separation wall 1 is such that the minimum distance Lmin between the heat action surfaces measured without penetrating the separation wall does not reach the above range for the distance Doh between the heat action surface and the center of the orifice.
If the length of the separating wall 117 is short, interference effect of liquid discharge occurs between adjacent orifices, and conversely, if the length of the separating wall 117 is so long that it exceeds the above range, the conventional individual liquid flow path method As in the case, the tracking characteristics at high frequencies deteriorate. In order to make the effects of the present invention more effective, it is preferable that 1≦Lmin/Doh≦100, more preferably 2≦Lmin/Doh≦40, and optimally 4≦Lmin/Doh≦20. It is a good idea to install an isolation wall. The isolation wall 117 separates the orifice plate 107 and the liquid chamber 1.
Although it is provided in contact with the protective layer 113 constituting the bottom surface of 10, it may be in contact with the front wall plate 103 as in the case of FIG. 3, or it may not be in contact with the front wall plate 103 as in the case of FIG. Tomoyoshi. 6 and 7 are schematic diagrams showing a modification of the installation style of the separation walls 117 in the liquid jet recording device of the present invention, and FIG. 6 shows the installation of the separation walls 117 having various lengths. In this case,
Lmin is the minimum value among _L1 to _L4 . In addition, the seventh example is an example in which the liquid chamber is divided into two by a separating wall 117, and adjacent heat-acting surfaces alternately belong to one liquid chamber. In this case, the separating wall 117
The distance between heat-active surfaces measured without penetrating 7 is not measured as the distance between adjacent heat-active surfaces, but as the distance between adjacent heat-active surfaces, and is the smaller of L ₁ and L ₂ . This value is taken as Lmin. Hereinafter, the present invention will be explained in more detail according to Examples. Example 1 Si whose surface was thermally oxidized to form _two SiO layers with a thickness of 3 μm
By etching the substrate as a common liquid chamber part
100 μm was removed. Next, a Ta layer with a thickness of 2000 Å as a heating resistance layer and an Al layer with a thickness of 1 μm as an electrode were laminated, and then a photolithography process was performed to form a shape of 40 μm x 100 μm.
A heat generating part (heater) array was formed with a pitch of 100 μm. In addition, as a film to prevent oxidation of the Ta layer, to prevent penetration of ink liquid, and to resist mechanical shock caused by bubbles generated when the liquid receives thermal energy, we sequentially added _two 0.5 μm thick SiO layers and 1 μm thick SiC layer. A protective layer was formed by laminating by sputtering. Next, on this substrate, as shown in Figures 1 to 3, an isolation wall with a width of 50 μm and a height of 80 μm, a front wall plate, a rear wall plate, two side wall plates, an orifice plate, and a supply pipe are installed. An injection recording device was created. The width of the liquid flow path partitioned by the separation wall is 50μm, and the common liquid chamber (here, the liquid flow path section partitioned by the separation wall is not included).
The distance between and the heat acting surface is 500μm, and Lmin is approximately
It was 1050μm. The orifice plate is made of a nichrome plate with a thickness of 40 μm, and an orifice with a diameter of 35 μm is formed by etching so as to be located directly above each heat-active surface. Therefore, the distance Doh between the heat acting surface and the center of the orifice was 120 μm in each case. This liquid jet recording device was driven by applying a rectangular voltage of 6 μsec. In this case, the highest frequency response fmax of droplet ejection was 7KHz, and no interference effect of liquid ejection occurred between adjacent orifices. Examples 2 to 7 and Comparative Example 1 A liquid jet recording device similar to that of Example 1 was manufactured except that the length of the separating wall to be installed was variously changed. These liquid jet recording devices were driven under the same conditions as in Example 1, and the highest frequency response fmax and the presence or absence of interference in liquid ejection between adjacent orifices were evaluated. The results are shown in Table 1. From this result, it was found that when Lmin/Doh is 1 or more, the interference effect of liquid discharge between adjacent orifices is considerably suppressed, and when Lmin/Doh is 2 or more, the interference effect is almost suppressed. Also,
It was found that when Lmin/Doh exceeds 500, the maximum frequency response fmax decreases considerably. Example 8 In Example 1, the height of the isolation wall to be installed was
50μm, distance between common liquid chamber and heat acting surface 320μm,
A liquid jet recording device similar to that of Example 1 was manufactured except that an orifice plate having a thickness of 30 μm was used. In other words, with this device, Lmin is approximately 690μm
, Doh is 80 μm, and Lmin/Doh is 8.6
The value was almost the same as in Example 1.
When this device was driven under the same conditions as in Example 1, the highest frequency response fmax was
At 7 KHz, the value was almost the same as in Example 1, and of course no interference effect of liquid discharge occurred between adjacent orifices. Examples 9 to 15 and Comparative Examples 2 and 3 In Example 1, a shape of 80 μm×
Except for forming a 100μm heater array with a 100μm pitch, using a 20μm thick orifice plate, and installing various lengths of isolation walls with a width of 20μm and a height of 20μm. A liquid jet recording device similar to that of Example 1 was manufactured. That is, in this device, Doh is 40 μm. These liquid jet recording devices were driven under the same conditions as in Example 1, and the highest frequency response was obtained.
The presence or absence of interference between fmax and liquid discharge between adjacent orifices was evaluated. The results are shown in Table 2.

【table】

【table】

【table】 [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 perspective view, and FIG. 2 is a diagram taken along the dashed-dotted line AB in FIG. 1. FIG. 3 is a schematic exploded view for explaining the internal structure. FIG. 4 is a partially enlarged plan view of an embodiment of the present invention;
FIG. 5 is a cutaway view taken along the dashed line XY in FIG. 6 and 7 are schematic diagrams showing a modification of the installation state of the separation wall 117 in the liquid jet recording apparatus of the present invention. 100: Liquid jet recording device, 101: Substrate, 1
02: Electric converter, 103: Front wall plate, 104: Side wall plate, 105: Rear wall plate, 106: Supply pipe, 10
7: Orifice plate, 108: Orifice, 10
9: Penetration, 110: Liquid chamber, 111: Heat generating resistance layer,
112: Selective electrode, 113: Protective layer, 114: Common electrode, 115: Heat action surface, 116: Heat generating part,
117: Isolation wall, Lmin: Minimum distance between heat-active surfaces measured without penetrating the isolation wall,
Doh: Distance between the heat acting surface and the corresponding center of the orifice.

Claims (1)

[Scope of Claims] 1. 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 the flying droplets. The means for generating the thermal energy is provided corresponding to a liquid chamber to which a liquid is supplied to form a liquid, a supply port for supplying the liquid to the liquid chamber, and a discharge port. a plurality of electrothermal converters, each of the electrothermal converters comprising:
A liquid jet recording device having a heat acting surface on the bottom surface of the liquid chamber as a surface on which generated thermal energy acts on the liquid, and each of the ejection ports being provided opposite to the bottom surface. In this case, a separation wall provided in the liquid chamber that isolates adjacent heat-action surfaces and discharge ports, respectively, has a minimum value of the distance between the heat-action surfaces measured without penetrating the separation wall. A liquid jet recording device characterized in that it is installed so as to satisfy the relational expression 1≦Lmin/Doh≦500, where Lmin is the distance between the heat acting surface and the center of the corresponding ejection port.