JPS62152865A - Ink jet recording head - Google Patents

Abstract

PURPOSE:To enable sufficient chromatic gradation recording to be performed by providing plural thermal energy generators independently of each other on the internal surface of a wall constituting a liquid flow channel in such a way that the generators may surround the liquid flow channel in a drivable manner. CONSTITUTION:Thermal energy generators are provided on the internal surfaces of four walls constituting a flow channel 1, and the thermal energy generators 2a to 2d are constituted in an independently drivable manner. Consequently liquid droplets having a minimum diameter are discharged when only the thermal energy generator 2C driven. When only the thermal energy generators 2a, 2c are driven, liquid droplets having such a diameter as to form the second dot diameter are discharged, and when the thermal energy generators 2b to 2d are driven, liquid droplets having such a diameter as to form the third dot diameter are discharged. Liquid droplets having such a diameter as to form a maximum dot diameter can be obtained by driving all the thermal energy generators 2a to 2d. Thus it is possible to make four recordings each having a different density in a simple way and facilitate chromatic gradation recording.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an inkjet recording head, and more particularly to an inkjet recording head capable of performing gradation recording.

Prior Art The inkjet recording method produces extremely low noise during recording and is easy to print in color.

It has many advantages, such as the ability to record on so-called plain paper, and has been attracting increasing attention in recent years. Among them, thermal energy is applied to a body to generate bubbles in the liquid, and the rapid volume change of the bubbles is used to cause the liquid to sway and be discharged from an orifice for recording. The recording method is attracting a lot of attention because it is easy to miniaturize the device and allows for high-density arrangement of orifices.

However, the specific heat energy mentioned above? Since the inkjet recording method utilizes changes in the volume of bubbles during the process of their generation and disappearance, it is easy to accurately eject all of the liquid in accordance with the recording signal, but it is difficult to It was difficult to accurately control the amount of liquid in multiple stages. Therefore, gradation recording is performed by providing a plurality of thermal energy generating bodies for one orifice and driving the plurality of thermal energy generating bodies individually or simultaneously.

However, even with this method of providing multiple thermal energy generators, the positions from the orifice are different, which can cause problems in terms of liquid ejection efficiency, especially if the recording head is not used for a while. If the viscosity of the liquid near the orifice increases due to being left unattended, problems may occur such as the liquid may not be ejected reliably.

The present invention has been made in view of the above-mentioned problems, and a first object thereof is to provide an inkjet recording head that can perform sufficient gradation recording.

A further object of the present invention is to provide an inkjet recording head with high liquid ejection efficiency.

<Structure of the Invention> To achieve the above object, an inkjet recording head of the present invention includes an orifice for ejecting liquid and a thermal energy generating body that communicates with the orifice and generates thermal energy for ejecting the liquid. In the inkjet recording head having a plurality of g channels corresponding to one of the orifices, the plurality of thermal energy generating bodies surround the liquid channel on an inner surface of a wall constituting the liquid channel. They are provided so that they can be driven independently.

The present invention will be explained below with reference to the drawings.

The first factor is a companion explanatory diagram for explaining the present invention. 1st
In the figure, 1 is a liquid flow path, 2a, 2b.

2c and 2d are thermal energy generating parts. As shown in FIG. 1, in the present invention, thermal energy generating portions are provided on the inner surfaces of four walls forming the liquid flow path 1, respectively. These thermal energy generating parts 2a.

2b, 2c, and 2a are each configured to be able to be driven separately. Therefore, by controlling the number of thermal energy generating parts that move #A, it is possible to perform gradation recording. Note that the liquid is discharged in the direction of the arrow due to heat generation in these energy generating portions.

To explain further, when only the thermal energy generating section 2C is driven (of course, the other thermal energy generating sections 2a, 2b
, 2a), a droplet having the minimum diameter to form the minimum dot diameter is ejected, and when only the thermal energy generating parts 2a, 2C are driven (another (It is also possible to drive two thermal energy generators in combination), is the minimum dot diameter also the diameter to form a larger second dot diameter? The droplets having the same diameter are ejected, the thermal energy generators 2b and 2C92dt- are driven (the three thermal energy generators may be driven in another combination), and the second dot diameter area is also larger than the third dot. Droplets having diameters similar to those forming the dot diameter are ejected, and droplets having a diameter to form the maximum dot diameter are obtained by driving all four thermal energy generators 2a, 2b, 2c, and 2dl. be able to.

As described above, by driving all of the thermal energy generators of the inkjet recording head of the present invention, it is possible to easily perform original recording with four different densities, so that gradation recording can also be easily performed.

In the above description, an example is described in which the drive timings of the thermal energy generators are set at the same time.Next, by slightly shifting the drive timings of the respective thermal energy generators, even more gradation recording becomes possible.

Also, if it is necessary to record more gradations, it is possible to achieve smoother gradations by changing the driving voltage and/or driving pulse width and driving pulse waveform of the thermal energy generator. Recording can be done.

<Example> The second factor is a schematic perspective view for explaining the implementation of the present invention, and shows intermediate parts of an inkjet recording head. In the second factor, 3 is the channel wall, 4 is the substrate, 5μ common electrode, and 6b, 6c, and 6d are individual electrodes.

As shown in FIG. 2, in this example, first, a heat generating resistor layer is formed in a desired shape on a support, a pair of electrodes are provided, and a metal substrate having an electrothermal transducer is fabricated. Next, a photosensitive resin is provided on the fabricated substrate 4, and after exposure to a desired pattern, the channel walls 3 are formed. Next, the substrate 40
The entire surface is protected with a resist, etc., and the heating resistor layer 1 is connected to the channel wall 3.
The heat generating resistor layer is formed uniformly by, for example, a vapor deposition method (at this time, it is of course possible to add a step of removing unnecessary heat generating resistor layers). After that, select the desired area (the area that will become the heat generating part)? After protection with a resist or the like, a conductive layer is formed using a vapor deposition method, for example. Further, after removing the protective material such as the resist, the uncomfortable portions of the heating resistive layer and the conductive layer are removed by etching or the like to form a friendly electrical/thermal converter provided on the side surface of the channel wall 3.

This embodiment is shown in FIG. The inkjet recording head 7 is completely bottomed by bonding the entire top plate formed by the channel wall 3 and the substrate 4 and covering the top plate. A schematic plan view of this top plate is shown in FIG. In FIG. 3, 7 is a region where the channel wall 3 joins.

The inkjet recording head of the present invention is completed by positioning and bonding the intermediate part shown in FIG. 2 on the top plate shown in the third factor.

In reality, a next protective layer is further provided to protect the conductive layer serving as the electrode and the heating resistor layer from cavitation destruction caused by the disappearance of the ink supplied and the generated bubbles. FIGS. 4 and 5 are schematic cross-sectional views of an inkjet recording head provided with this protective layer.

FIG. 4 shows the completed head cut at a position corresponding to the dashed line 1-I' shown in FIG. 3.

Figure 5 shows the completed head shown in Figure 3 by the dot-dash line■
-B' is a schematic cross-sectional view of 7'C.

@ In Figures 4 and 5, 41 is a support, 42 is a heating resistor layer 43 is an individual t&, 44 is a protective layer, 45 and 49
is common 1! pole, 46 is the top plate support, 47 is the orifice,
48 is Himeji wall.

As shown in FIG. 4, the common electrode 49 provided on the channel wall 48 and the common electrode 45 provided on the top plate are electrically connected by joining the top plate.

Also, as shown in FIG. 5, in the liquid flow path.

Electrothermal converters are provided above and below the liquid flow path and on the flow path wall 48 (of course, the upper and lower sides of the liquid flow path can also be regarded as flow path walls). When liquids were actually ejected using the print head, liquids of different sizes could be ejected in accordance with the print signal.

That is, by changing the number of electrothermal transducers to be driven, liquids having four different diameters can be formed and one gradation recording can be performed.

In addition, by changing the drive voltage, it is possible to record a single image with even smoother gradations. We can provide an inkjet recording head that can be used for various purposes and has high ejection efficiency.

Further, according to the present invention, it was possible to provide an inkjet recording head in which non-ejection of the inkjet ink is less likely to occur.

It goes without saying that there are many possible variations that are not mentioned above within the scope of non-invention exemption.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram for explaining the present invention, Fig. 2 is a schematic perspective view for explaining a preferred embodiment of the present invention, and Fig. 3 is a schematic perspective view for explaining a preferred embodiment of the present invention.
□□ is a schematic plan view for explaining a preferred embodiment of the present invention, and FIGS. 4 and 5 are schematic cross-sectional views for explaining a preferred embodiment of the present invention. . 1...Liquid flow path, 2a, 2b, 2c, 2d
...Thermal energy generation section, 3 ... Channel wall, 4 ... Substrate, 5 ... Common electrode, 6
a, 6b, 6c, 6d...Individual electrodes.

Claims (1)

[Claims] Inkjet recording having an orifice for ejecting a liquid and a liquid flow path having a plurality of thermal energy generators corresponding to one of the orifices and communicating with the orifice and generating thermal energy for ejecting the liquid. An inkjet recording head characterized in that a plurality of the thermal energy generators are provided on an inner surface of a wall constituting the liquid flow path so as to surround the liquid flow path so as to be able to drive each one independently.