JP2759447B2 - Ink jet recording device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a heating element structure of a droplet discharge section of an ink jet recording apparatus using the action of thermal energy. [Prior Art] A conventional heating element structure of a droplet discharge portion of an ink jet recording apparatus using the action of thermal energy is disclosed in Japanese Patent Laid-Open No. 55-154171.
As described above, the heating element is formed on a substrate provided with one lower layer. [Problems to be Solved by the Invention] However, in the above-described conventional technology, when the heat conduction of the lower layer is good, the heat generated in the heating element is transmitted to the lower layer, and the temperature of the heating element is hardly increased, and is given to the heating element. If the liquid is not heated compared to the energy, that is, the energy efficiency will be poor, and if the heat conduction of the lower layer is poor, the largest temperature gradient will occur at the part of the lower layer in contact with the heating element and the stress due to thermal expansion However, there is a problem that the heat is applied to the heating element and the life of the heating element is shortened. Therefore, the present invention is to solve such a problem, and an object of the present invention is to provide an ink jet recording apparatus using the action of thermal energy having a high energy efficiency and a long life. [Means for Solving the Problem] An ink jet recording apparatus according to the present invention is an ink jet recording apparatus that applies thermal energy to a recording liquid to eject droplets as droplets. A lower layer on the heat-generating resistor layer side is formed of a material having a higher thermal conductivity than the lower layer on the substrate side. And a lower layer on the side of the heating resistor layer is formed thinner than a lower layer on the substrate side. [Embodiment] FIG. 1 shows an embodiment of an ink jet recording apparatus to which the present invention is applied. In FIG. 1, reference numeral 1 denotes an axial direction of a platen 3 guided by guide members 2 and 2. The carriage has a print head 4 mounted thereon and is configured to move the print head 4 in the width direction of the printing paper P. Note that reference numeral 5 in the drawing denotes an ink tank. Therefore, the details of the present invention will be described below based on an embodiment of the droplet discharge unit of the print head of the recording apparatus of the present invention. FIG. 2 is a cross-sectional view of a droplet discharge section according to the embodiment of the present invention.
The recording liquid 13 is supplied to the gap formed by the heating element substrate and the top plate 21 on which the heating resistance layer 18 and the electrode layer 19 are laminated and patterned, the protection layer 20 is laminated and the heating section 12 is formed. When the heating section 12 is energized, the recording liquid 13 is heated and vapor bubbles 14 are generated, and the recording liquid is discharged from the discharge port 11 by the energy of this state change. FIG. 3 shows the substrate-side lower layer 16, the heating element-side lower layer 17, the heat-generating resistor layer 18, and the protective layer 20 in the heat-generating state of the heat-generating portion in FIG.
FIG. 3 is a schematic diagram for showing a temperature distribution in a thickness direction of a layer, in which a vertical axis indicates a layer thickness direction and a horizontal axis indicates a temperature. The droplet discharge unit of the present invention is provided with a heating element side lower layer 17 and a substrate side lower layer 16 under a heating resistance layer 18, and the heating element side lower layer 17 is formed of a material having a higher thermal conductivity than the substrate side lower layer 16. The heating element side lower layer 17
In the heat generating state, only a small temperature gradient can be generated as shown in FIG. Therefore, the stress generated due to the thermal expansion inside the heating element side lower layer 17 is small, so that the occurrence of cracks is extremely small and the heating resistance layer is not adversely affected. Further, the heat transmitted to the substrate side is controlled by the substrate-side lower layer 16 having a low thermal conductivity, so that the energy efficiency can be increased. The substrate 15 is desirably a material having high thermal conductivity,
As a result, the heat of the heat-generating portion after the power is turned off is easily transmitted to the outside world, so that the temperature of the heat-generating portion rapidly falls,
The response frequency can be increased. The material of the substrate 15 is preferably a metal, ceramics, photosensitive glass, or the like. The substrate-side lower layer 16 is desirably formed of a material having a low thermal conductivity and a low thermal expansion coefficient. The thermal conductivity of the lower layer 16 on the substrate side must be low in order to limit the heat transmitted to the substrate in the heat-generating state, and the substrate side has the largest temperature gradient in the lower layer 16, so that the stress due to thermal expansion is reduced. It is desirable that the coefficient of thermal expansion is small in order to reduce the coefficient. As the material of the substrate-side lower layer 16, silicon oxide and a material mainly containing silicon oxide are preferable. In addition, the thickness of the substrate-side lower layer 16 is preferably thick to limit the heat transferred to the substrate 15 in the heat generation state and increase the energy efficiency, but if too thick, the fall of the temperature is deteriorated, and the response frequency is limited. For,
For example, in the case of silicon oxide and a material containing silicon oxide as a main component, the thickness of the substrate-side lower layer 16 is preferably 2 to 100 micrometers, and most preferably 4 to 20 micrometers. The heating element side lower layer 17 needs to be formed of a material having a higher thermal conductivity than the substrate side lower layer 16, and is two times smaller than the substrate side lower layer 16 in order to reduce stress due to thermal expansion.
Desirably more than twice as good. As a material of the heating element side lower layer 17, a material such as aluminum oxide, magnesium oxide, zirconium oxide, and silicon carbide is preferable. Also, the thickness of the heating element side lower layer 17 is desirably smaller than the lower layer 16, since energy efficiency is deteriorated if its heat capacity is large, and is most preferably 0.05 to 1 micrometer. It is desirable that the heat generating resistance layer 18 and the protective layer 20 have values close to the thermal conductivity and thermal expansion coefficient of the heat generating element side lower layer 17 so as not to apply stress to the heat generating resistive layer 18. Optimally, layer 17 is formed of the same material. [Effects of the Invention] As described above, according to the present invention, a heat-generating resistor layer for generating thermal energy is formed by laminating two lower layers on a substrate so as not to contact the lower layer on the substrate side. The lower layer on the side of the heating resistor layer has a higher thermal conductivity and a smaller thickness than the lower layer on the side of the substrate, thereby reducing the temperature gradient of the lower layer on the side of the heating resistor layer and thermally expanding the lower layer. In addition to preventing the occurrence of cracks that adversely affect the heat-generating resistance layer by reducing the stress generated by the above, the heat transfer to the substrate is limited by reducing the heat conductivity of the lower layer on the substrate side and increasing its thickness, thereby improving energy efficiency. To raise.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view showing one embodiment of an ink jet recording apparatus of the present invention. FIG. 2 is a cross-sectional view of a droplet discharge section in the embodiment of the ink jet recording apparatus of the present invention. FIG.
FIG. 3 is a schematic diagram illustrating a temperature distribution in a thickness direction of a layer in a heat generation state of a heat generation unit in the drawing. DESCRIPTION OF SYMBOLS 1 ... Carriage 2 ... Guide member 3 ... Platen 4 ... Print head 5 ... Ink tank 11 ... Discharge port 12 ... Heat generation part 13 ... Recording liquid 14 ... Vapor bubbles 15 ... Substrate 16 ... Substrate side lower layer 17 Heating element side lower layer 18 Heat generating resistance layer 19 Electrode layer 20 Protective layer 21 Top plate

Claims (1)

(57) [Claims] What is claimed is: 1. An ink jet recording apparatus, comprising: applying a thermal energy to a recording liquid to discharge the recording liquid as droplets; a heating resistance layer for generating the thermal energy; A lower layer on the heating resistor layer side is formed of a material having a higher thermal conductivity than the lower layer on the substrate side, and a lower layer on the heating resistor layer side is formed on the substrate side. An ink jet recording apparatus characterized by being formed thinner than a lower layer. 2. 2. The ink-jet recording apparatus according to claim 1, wherein the thickness of the lower layer on the side of the heating resistor layer is 0.05 to 1 micrometer, and the thickness of the lower layer on the substrate side is 2 to 100 micrometers. .