JPH01186331A - Liquid jet recording head - Google Patents

Abstract

PURPOSE:To perform stable emission at high response frequency by providing at least one filter in a liquid chamber or on the upstream side of the liquid chamber and making the opening cross-sectional area of the flow passage at the part where the flow passage communicates with the liquid chamber equal to or larger than that of an orifice. CONSTITUTION:A head part I consists of a liquid chamber part A and a flow passage part B, and a hole 1 for mounting an ink cartridge part II in a freely detachable manner is provided to the liquid chamber part A and a heat generator 4 for generating air bubbles 3 in a recording medium 2 is provided to the flow passage part B. At least one filter 5 is provided in a liquid chamber or on the upstream side of the liquid chamber to prevent clogging and, by providing the filter so as to separate the same from the flow passage, it is prevented that no ink is sufficiently replenished to the flow passage by the fluid resistance of the filter. Further, by making the opening cross-sectional area Si at the part where the flow passage communicate with the liquid chamber equal to or larger than the opening cross-sectional area So of an orifice, it is prevented that no ink is replenished to the flow passage even if a recording speed (emission speed, response frequency) is increased and stable emission is always performed.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a liquid jet recording head, and more particularly to a bubble jet type ink jet head.

Conventional non-impact recording methods have recently attracted attention because the noise generated during recording is so small that it can be ignored. Among them, high-speed recording is possible,
In addition, the so-called inkjet recording method, which allows recording on plain paper without the need for special fixing treatment, is an extremely powerful recording method, and various methods have been proposed, improved, and commercialized. Some have been developed, and efforts are still being made to put them into practical use.

In this type of inkjet recording method, recording is performed by causing droplets of a recording liquid called ink to fly and adhere to a recording member. There are several types of methods depending on the control method used to control the flight direction of the generated recording liquid droplets.

First, the first method is, for example, TJ S P 3060429.
(Tele type method), in which droplets of recording liquid are generated by electrostatic absorption, and the generated recording liquid droplets are controlled by an electric field in accordance with a recording signal, and are placed on a recording member. Recording is performed by selectively depositing recording liquid droplets.

More specifically, an electric field is applied between the nozzle and the accelerating electrode to eject a negatively charged recording liquid droplet from the nozzle, and the ejected recording liquid droplet responds to the recording signal. The droplet is caused to fly between x and y deflection electrodes configured to be electrically controllable, and the droplet is selectively attached to the recording member by changing the intensity of the electric field to perform recording.

The second method is described, for example, in USP 3596275, U
The method disclosed in SP 3298030 etc. (Swe
et method), in which droplets of recording liquid with a controlled amount of charge are generated by a continuous vibration generation method, and a --like electric field is applied to the generated droplets with a controlled amount of charge. Recording is performed on a recording member by flying between deflection electrodes.

Specifically, the orifice (discharge port) of a nozzle, which is a part of the recording head to which the piezo vibrating element is attached.
A charged electrode configured to have a recording signal applied thereto is arranged at a predetermined distance in front of the piezo vibrating element, and an electric signal of a constant frequency is applied to the piezo vibrating element to mechanically vibrate the piezo vibrating element, A small droplet of recording liquid is ejected from the ejection port. At this time, charges are electrostatically induced in the recording liquid droplet discharged by the charging electrode, and the droplet is charged with an amount of charge corresponding to the recording signal. When a droplet of recording liquid with a controlled amount of charge flies between deflection electrodes to which a constant electric field is uniformly applied, it is deflected according to the amount of charge applied.
Only the droplets carrying the recording signal are allowed to deposit on the recording member.

The third method is, for example, the method disclosed in U.S.P. 3416153 (Hertz method 1), in which an electric field is applied between a nozzle and a ring-shaped charging electrode, and small droplets of recording liquid are generated by a continuous vibration generation method. This is a method that generates atomized light and records it. That is, in this method, the atomization state of the droplets is controlled by modulating the electric field intensity generated between the nozzle and the charged electrode according to the recording signal, and the gradation of the recorded image is produced.

The fourth method is, for example, the method disclosed in USP 3747120 (Stemme method), and this method is fundamentally different in principle from the above three methods.

That is, in all three methods, the droplets of recording liquid ejected from the nozzle are electrically controlled while they are in flight, and the droplets carrying the recording signal are selectively attached to the recording member. In contrast, this Stemme method
Recording is performed by ejecting small droplets of recording liquid from an ejection port in response to a recording signal.

In other words, the Stemme method applies an electrical recording signal to a piezo vibrating element attached to a recording head that has an ejection port for discharging recording liquid, and converts this electrical recording signal into mechanical vibration of the piezo vibrating element. In this method, recording is performed by ejecting small droplets of recording liquid from the ejection opening and adhering them to the recording member according to the mechanical vibration.

These four conventional methods each have their own advantages, but there are also points that can be solved in the other method.

That is, in the first to third methods, the direct energy for generating droplets of the recording liquid is electrical energy, and the deflection control of the droplets is also electric field control.

Therefore, although the first method is simple in structure,
It is not suitable for high-speed recording because it requires a high voltage to generate droplets and it is difficult to form a recording head with multiple nozzles.

The second method allows the recording head to have multiple nozzles and is suitable for high-speed recording, but it has a complicated structure, and the electrical control of recording liquid droplets is sophisticated and difficult, and satellite dots are placed on the recording member. There are problems such as easy occurrence of.

The third method has the advantage that an image with partial gradation can be recorded by atomizing recording liquid droplets, but on the other hand, it is difficult to control the atomization state, and the recorded image There are various problems such as fogging, difficulty in creating a multi-nozzle recording head, and unsuitability for high-speed recording.

The fourth method has relatively many advantages compared to the first to third methods. In other words, the structure is simple, and since recording is performed by ejecting recording liquid from the ejection opening of the nozzle on-demand, it is possible to reduce the number of small droplets that fly as in the first to third methods. Second, it is not necessary to collect droplets that are not needed to record an image, and unlike the first and second methods, there is no need to use a conductive recording liquid, and the material of the recording liquid is It has great advantages such as a high degree of freedom. On the other hand, on the other hand, it is difficult to make a recording head with multiple nozzles due to problems in processing the recording head, and it is extremely difficult to miniaturize a piezoelectric vibrating element having a desired resonance number. This method has disadvantages such as that it is not suitable for high-speed recording because the recording liquid droplets are ejected into flight using the mechanical energy of the mechanical vibration of the piezoelectric vibrating element.

Furthermore, Japanese Patent Application Laid-Open No. 48-9622 (the above-mentioned US P3
No. 747120) discloses, as a modification, the use of thermal energy instead of the mechanical vibration energy provided by means such as the piezo vibration element.

That is, the above-mentioned publication describes the use of a heating coil that directly heats a liquid as a pressure increasing means in place of the piezo vibrating element in order to generate steam that causes a pressure increase.

However, in the above publication, the liquid ink in the bag-shaped ink chamber (liquid chamber), which has only one opening through which liquid ink can go in and out, is directly heated and vaporized by energizing the heating coil as a pressure increasing means. However, when discharging liquid continuously and repeatedly, it is not clear how to heat it.
There is nothing to suggest. In addition, the heating coil is located at the deepest part of the bag-shaped liquid chamber far from the liquid ink supply path, which makes the head structure complicated and requires continuous high-speed printing. It is not suitable for repeated use.

Moreover, with the technical content described in the above-mentioned publication, it is not possible to quickly prepare for the next liquid discharge after discharging the liquid using the generated heat, which is important in practice.

As described above, conventional methods have advantages and disadvantages in terms of structure, high-speed recording, multi-nozzle recording heads, generation of satellite dots, and fogging of recorded images. There was a restriction that it could only be applied.

Furthermore, in Japanese Patent Application Laid-Open No. 55-109669, it is stated that the cross-sectional area of the opening of the communication port between the chamber that applies a discharge force to the liquid and the supply source that supplies the liquid to the cough chamber is defined as the opening of the orifice that discharges the liquid from the chamber. Equal to or smaller than the cross-sectional area,
A bubble jet type liquid jet recording head is disclosed that prevents orifice clogging.

FIG. 29 is an exploded perspective view for explaining the liquid jet recording head disclosed in the above-mentioned Japanese Patent Application Laid-open No. 55-109669. Here, a heating element 142 is provided on the back surface thereof as an operating part. A separate grooved plate 143 includes an action chamber 144 and an ink reservoir 145.
The groove is molded. Materials constituting the grooved plate 143 include glass, ceramics, heat-resistant plastic, and the like. Further, the opening of the contact portion 146 between the ink reservoir 145 and the action chamber 144 is narrower than the ink discharge orifice 147.

Further, the width of the groove serving as the action chamber 144 is designed to approximately correspond to the heating element 142, and after aligning the width, the grooved plate 143 and the heating element installation board 141 are bonded using adhesive or the like. . In this way, the heating element installation board 1
41 and the grooved plays 1 to 143 are integrated to complete the recording head. Ink is supplied to the ink reservoir 145 as shown by the arrow, but at this time the ink is pressurized so that the flow of the ink is approximately in the direction of the arrow.

Then, the ink further flows into the action chamber 14 from the contact opening 146.
4 and always fills the vacancy.

Now, when a signal is applied to the heating element 142 from the outside, the heating element 142 generates heat and imparts thermal energy to the ink around it. The ink that has received thermal energy undergoes a change in state such as volumetric expansion or generation of bubbles, resulting in a pressure change, and this pressure change is transmitted in the direction of the ejection orifice 147, and ink droplets are ejected from the orifice 147. At this time, the contact opening 146 is narrower than the orifice 147, and the working chamber 144 is structured to prevent large particles larger than the orifice diameter from entering.

Furthermore, since the ink is pressurized, it always flows in the direction of the arrow, and impurities in the ink do not accumulate near the contact opening 146. Even if an impurity smaller than the diameter of the opening 146 passes through it, the impurity will flow through the orifice 1 because the diameter of the orifice 147 is larger than the impurity particle size.
The ink is discharged to the outside together with the ink without clogging the ink.

As mentioned above, the invention described in JP-A No. 55-109669 was made for the purpose of preventing clogging of the orifice, and with the above structure, the orifice will not be clogged. However, the connection port becomes clogged and is completely meaningless. Furthermore, because the communication port is small, sufficient ink is not replenished into the orifice (and the flow path in front of it), so it is necessary to wait until ink is replenished for the amount of ink ejected, and the print head responds. The disadvantage is that the speed is extremely slow.

Purpose The present invention was made in view of the above-mentioned circumstances.
In particular, this method was developed with the aim of achieving stable ejection at a high response frequency in a bubble jet type liquid jet recording head.

Structure In order to achieve the above-mentioned object, the present invention provides a thermal energy application unit that accommodates the recording liquid introduced, generates bubbles in the recording liquid by heat, and generates an acting force as the volume of the bubbles increases. an orifice connected to the flow path for ejecting the recording liquid as droplets by the acting force; and an orifice connected to the flow path for introducing the recording liquid into the flow path. A liquid jet recording head comprising a liquid chamber and a means for introducing the recording liquid into the liquid chamber, the liquid jet recording head having at least one filter means in the liquid chamber or upstream of the liquid chamber, and having at least one filter means in the liquid chamber or on an upstream side of the liquid chamber; The opening cross-sectional area of the flow path at the portion communicating with the liquid chamber is equal to or larger than the opening cross-sectional area of the orifice. Hereinafter, the present invention will be explained based on examples.

FIG. 1 is a diagram for explaining an embodiment of a liquid jet recording head according to the present invention. FIG. 1(a) is a sectional view of the head, and FIG. 1(b) is a plan sectional view of the head. , Figure 1 (b
) shows a diagram when the head is viewed from above so that the difference in the opening cross-sectional area SO1 of the orifice portion a and the opening cross-sectional area Si of the portion where the flow path and the liquid chamber communicate can be seen. In the figure, ■ is a head section, and ■ is a means for introducing recording liquid into the liquid chamber of the head section I, such as an ink cartridge. Part A has a hole 1 for removably attaching the ink cartridge part ■.
A bubble 3 is provided in the recording liquid 2 in the flow path section B.
A heating element (heater) 4 is provided to generate heat. According to the present invention, at least one filter 5 is provided within the liquid chamber or upstream of the liquid chamber. Although FIG. 1(b) shows an example in which the filter 5 is disposed inside the liquid chamber, for example, the filter may also be disposed at the part where the ink cartridge is connected to the liquid chamber via the O-ring 6. good. This filter 5 is provided firstly for the purpose of preventing clogging, and secondly, by providing it away from the flow path (provided in the liquid chamber or upstream of the liquid chamber), the flow path is blocked by the fluid resistance of the filter. recording liquid (ink)
This was designed to improve the conventional drawback of not being sufficiently replenished.

Therefore, in the present invention, the above So and Si satisfy So≦
In this way, by making the opening cross-sectional area Si of the part where the flow path and the liquid chamber communicate with each other equal to or larger than the opening cross-sectional area So of the orifice, the recording speed (ejection speed, response frequency) can be increased. Even if the recording liquid is raised, the recording liquid will not be replenished into the flow path, and stable ejection is always performed.

FIG. 2 is a block diagram for explaining the functions of the head according to the present invention as described above. In the figure, 11 is a means for supplying recording liquid into the liquid chamber, for example, a cartridge; 12 is a liquid chamber;
13 is the part where the flow path and the liquid chamber communicate (part b in Fig. 1), 1
Reference numeral 4 denotes a heat acting part, 15 denotes an orifice part (part a in FIG. 1), the part to the left of the line X--X in the figure is the part where the filter is provided, and the part surrounded by the dotted line is the flow path part.

As is clear from the above description, with the above configuration: 1. Clogging can be prevented by providing a filter.

2. By providing the filter within the liquid chamber or upstream from the liquid chamber, insufficient ink replenishment due to fluid resistance of the filter can be prevented.

3. By making the opening cross-sectional area S1 of the portion where the flow path and the liquid chamber communicate with each other equal to or larger than the opening cross-sectional area So of the orifice, insufficient ink supply to the flow path can be prevented.

Therefore, the recording liquid can be ejected at high speed without clogging.

FIG. 3 is a diagram for explaining the operation of a bubble jet head as an example of an ink jet head to which the present invention is applied, FIG. 4 is a perspective view showing an example of a bubble jet head, and FIG. Figure 6 is a perspective view when the head shown in Figure 4 is disassembled into a lid substrate (Figure 5 (a)) and a heating element substrate (Figure 5 (b)), and Figure 6 is a perspective view of Figure 5 (a). 21 is a perspective view of the lid substrate shown in FIG.
22 is a heating element substrate, 23 is a recording liquid inlet, 24 is an orifice, 25 is a channel, 26 is a region for forming a liquid chamber, 27 is an individual (independent) electrode, 28 is a common electrode, and 29 is a heating element (heater), 30 is ink, 31 is a bubble, and 32 is a flying ink droplet, and the present invention is applied to such a bubble jet type liquid jet recording head. first, third
Ink ejection by a bubble jet will be described with reference to the figures. (a) is a steady state, in which the surface tension of the ink 30 and external pressure are in equilibrium on the orifice surface.

In (b), the heater 29 is heated until the surface temperature of the heater 29 rises rapidly and boiling development occurs in the adjacent ink layer, and microbubbles 31 are scattered.

(c) shows a state in which the adjacent ink layer that is rapidly heated on the entire surface of the heater 29 is instantaneously vaporized, forming a ``a-boiling film'' and the bubbles 31 grow. At this time, the pressure inside the nozzle increases by the amount of bubble growth, and the balance with the external pressure on the orifice surface is lost, causing an ink column to begin to grow from the orifice.

(d) shows a state in which the bubble has grown to its maximum, and ink 30 corresponding to the volume of the bubble is pushed out from the orifice surface. At this time, no current is flowing through the heater 29, and the surface temperature of the heater 29 is decreasing. The maximum value of the volume of the bubble 31 is slightly delayed from the timing of electric pulse application.

(e) shows a state in which the bubbles 31 are cooled by ink or the like and begin to contract. At the leading end of the ink column, the ink moves forward while maintaining the extruded speed, and at the rear end, the ink flows back from the orifice surface into the nozzle due to a decrease in nozzle internal pressure as the bubbles contract, creating a constriction in the ink column.

In (f), the air bubbles 31 are further contracted, and the E1Funk is in contact with the heater surface, causing the heater surface to be cooled even more rapidly. At the orifice surface, the external pressure is higher than the nozzle internal pressure, so the meniscus is largely moving into the nozzle. The tip of the ink column becomes a droplet and flies toward the recording paper at a speed of 5 to 10 m/see.

In (g), the air bubbles have completely disappeared in the process of refilling the orifice with ink by capillary action and returning to the state of (a).

FIG. 7 is a diagram showing a typical example for explaining the main part configuration of the liquid jet recording head as described above, and FIG.
FIG. 7(b), which is a detailed front partial view of the bubble jet recording head seen from the orifice side, is a partial cross-sectional view taken along the line indicated by the dashed line XX in FIG. 7(a). .

The recording head 41 shown in these figures has a predetermined number of grooves of a predetermined width and depth at a predetermined linear density on a substrate 43 on which an electrothermal transducer 42 is provided on the back surface. By bonding the grooved plate 44 so as to cover the substrate 43, a liquid discharge portion 46 including an orifice 45 for ejecting liquid is formed. Liquid discharge part 46
The heat acting part 47 is a place where the thermal energy generated by the orifice 45 and the electrothermal converter 42 acts on the liquid to generate bubbles and cause a sudden change in state due to expansion and contraction of the volume. have

The heat acting part 47 is located above the heat generating part 48 of the electrothermal converter 42, and has a heat acting surface 49, which is a surface of the heat generating part 48 that comes into contact with the liquid, as its lower surface. The heat generating section 48 is
It is composed of a lower layer 50 provided on the base 43, a heating resistance layer 51 provided on the lower layer 50, and an upper layer 52 provided on the heating resistance layer 51.

The heating resistor JW5.1 includes the N5 to generate heat.
Electrodes 53 and 54 for energizing 1 are provided on its surface, and a heat generating portion 48 is formed by a heat generating resistive layer between these electrodes.

The electrode 53 is an electrode common to the heat generating section of each liquid discharging section, and the electrode 54 is a selection electrode for selectively generating heat in the heat generating section of each liquid discharging section. It is provided along the flow path.

The protective layer 52 is a heat generating resistor layer 51 in the heat generating section 48.
In order to chemically and physically protect the liquid from the liquid used, the heating resistance layer 51 and the liquid filling the liquid flow path of the liquid discharge part 46 are separated, and the electrodes 53 and 54 are connected through the liquid.
It has the role of preventing short circuits between adjacent electrodes and further preventing electrical leakage between adjacent electrodes.

The liquid flow paths provided in each liquid discharge part are communicated with each other via a common liquid chamber (not shown) that constitutes a part of the liquid flow path upstream of each liquid discharge part. Due to design considerations, the electrodes 53 and 54 connected to the electrothermal converter 42 provided in each liquid discharge section are protected by the upper layer and are connected to the bottom of the common liquid chamber on the upstream side of the heat acting section. It is set up to pass through.

In such a liquid jet recording head, as shown in FIG. The heat generating section 48 consisting of the heat generating resistor layer connected between the pair of electrodes 53 and 54 (which is the common electrode 532 and the selection electrode 54) is arranged at a predetermined position on the substrate. It was formed by stacking them in such a way that Therefore, the common electrode 53 has a folded shape, and the common electrode 53 and the selection electrode 54 are arranged alternately, so that the plurality of heat generating parts are arranged with the common electrode sandwiched therebetween.

FIG. 8 is a detailed diagram for explaining the structure of a bubble generating means using a heating resistor, in which 61 is a heating resistor, 62
63 is an electrode, 63 is a protective layer, and 64 is a power supply device. Useful materials for forming the heating resistor 61 include, for example, a tantalum-8jO2 mixture, tantalum nitride,
Nichrome, silver-palladium alloy, silicon semiconductor, or hafnium, lanthanum, zirconium, titanium, tantalum, tungsten, molybdenum, niobium, chromium,
Examples include borides of metals such as vanadium.

Among the materials constituting these heating resistors 61, °.

Metal borides are particularly good.
Among them, hafnium boride has the best properties, followed by zirconium boride, lanthanum boride, tantalum boride, vanadium boride, and niobium boride.

The heating resistor 61 can be formed using the above-mentioned materials using techniques such as electron beam evaporation and sputtering. The film thickness of the heating resistor 61 is determined according to its area, material, shape and size of the heat-acting part, and actual power consumption, etc. so that the amount of heat generated per unit time is as desired. However, in the normal case, 0.001
~5 μm, preferably 0.01 to 1 μm.

As the material constituting the electrode 62, many commonly used electrode materials can be effectively used, and specifically,
For example, A Q , A g , Any P t
Examples include gCu, and these are used to provide a predetermined size, shape, and thickness at a predetermined position by a method such as vapor deposition.

The characteristics required of the protective layer 63 are to protect the heat generating resistor 61 from the recording liquid without preventing the heat generated by the heat generating resistor 61 from being effectively transferred to the recording liquid. Examples of useful materials for forming the protective layer 63 include silicon oxide, silicon nitride, magnesium oxide, aluminum oxide, tantalum oxide, and zirconium oxide. It can be formed by The thickness of the protective layer 63 is normally 0.01 to 10 μm, preferably 0.1 to 5 μm, and most preferably 0.1 to 3 μm.

The recording head created as described above is supplied with recording liquid at a pressure such that the recording liquid will not be ejected from the ejection port when the heating resistor does not generate heat, and at the same time supplying the recording liquid in pulses to the electric/thermal converter according to the image signal. When a voltage was applied and recording was performed, a clear image was obtained.

FIG. 9 is a block diagram showing an example of the heating element driving circuit at that time, and 71 is a known optical internal cuff sensor unit for reading consisting of a photodiode etc. The image signal is processed by a processing circuit 72 consisting of a circuit such as a comparator, and then input to a drive circuit 73. The drive circuit 73 drives the recording head 74 by controlling the pulse width, pulse amplitude, repetition frequency, etc. in accordance with a human input signal.

For example, in the simplest recording, the input image signal is discriminated between black and white in the processing circuit 72 and input to the drive circuit 73. In the drive circuit 73, the pulse width and pulse amplitude for obtaining an appropriate droplet diameter and the repetition frequency for obtaining a desired recording droplet density are converted into controlled signals to drive the recording head 74.

In addition, as another recording method that takes gradation into consideration, one is to perform recording by changing the droplet diameter, and the other is to perform recording by changing the number of recording droplets as follows. You can also do it.

First, in the recording method of changing the droplet diameter, the image signal inputted by the optical in-cabin sensor section 71 is converted into an agitating signal of pulse width and pulse amplitude of each level determined to obtain the desired droplet diameter. Drive circuit 7 having multiple output circuits
The processing circuit 72 determines which of the three signal levels should be used for outputting the signal and processes the signal. In addition, in the method of changing the number of recording droplets, the optical internal cuff sensor section 7
The input signal to 1 is A/D converted and outputted in the processing circuit 72, and according to the output signal, the drive circuit 73 controls the recording head so that recording is performed by changing the number of ejected droplets per one input signal. Outputs a signal to drive 74.

Alternatively, a similar device may be used to supply the recording liquid to the recording head 74 at a pressure higher than the pressure at which the recording liquid overflows from the ejection port without the heating resistor generating heat, while performing electrothermal conversion. When recording was performed by applying a voltage to the body in the form of continuous repeated pulses, it was confirmed that droplets of a number corresponding to the applied frequency were ejected stably and with a uniform diameter.

From this point of view, it has been found that the recording head 74 is extremely effectively applied to continuous ejection at high frequencies.

Further, since the recording head, which is the main part of the recording apparatus, is minute, a plurality of recording heads can be easily arranged, and a high-density multi-orifice recording head is possible.

FIG. 10 is a diagram for explaining another means for generating bubbles in the recording liquid, in which 81 is a laser oscillator, 82 is a light modulation drive circuit, 83 is a light modulator, 84 is a scanner, and 85
is a condenser lens, and a laser beam generated by a laser oscillator 81 is pulse-modulated in an optical modulator 82 according to an image information signal that is input to an optical modulation drive circuit 82, electrically processed, and output. The pulse-modulated laser light passes through a scanner 84 and is focused by a condensing lens 85 on the outer wall of the thermal energy acting section, heating the outer wall 86 of the recording head and causing the inner recording liquid 87 to be heated. to generate air bubbles. Alternatively, the wall 86 of the thermal energy application section is made of a material that is transparent to the laser beam, and the laser beam is focused by the condensing lens 85 on the recording liquid 87 inside to directly heat the recording liquid. Bubbles may be generated by

FIG. 11 is a diagram for explaining an example of a printer using laser light as described above. This example shows an example in which the entire area (width) is covered.

Laser light emitted from the laser oscillator 81 is guided to the entrance opening of the optical modulator 83. In the optical modulator 83, the laser beam undergoes intensity modulation according to the image information input signal to the optical modulator 83. The modulated laser beam is reflected by a reflecting mirror 8.
8 bends its optical path toward the beam expander 89 and enters the beam expander 89 . The beam expander 89 expands the beam diameter while remaining parallel light. Next, the laser beam with expanded beam diameter is
The light is incident on a rotating polygon mirror 9o that rotates at a constant high speed. The laser beam swept by the rotating polygon mirror 9o is focused by a condenser lens 85 onto the outer wall 86 of the thermal energy application section of the drop generator or onto the recording liquid inside. As a result, air bubbles are generated in each thermal energy applying portion, and recording droplets are ejected to perform recording on the recording paper 92.

FIG. 12 is a diagram showing still another bubble generating means. In this example, a pair of discharge electrodes 100 arranged on the inner wall side of the thermal energy application section receive a high voltage pulse from a discharge device 101. This device generates an electrical discharge in water, and the heat generated by the electrical discharge instantly forms bubbles.

13 to 20 are diagrams showing specific examples of the discharge electrode shown in FIG. 12, respectively. In the example shown in FIG. often(
It is designed to cause a discharge (with low energy).

In the example shown in FIG. 14, two flat plate electrodes are used so that air bubbles are stably generated between the electrodes. The position of generated bubbles is more stable than needle-shaped electrodes.

The example shown in FIG. 15 is one in which the electrode has a substantially coaxial hole. The holes in the two electrodes serve as guides, making the position of the bubbles even more stable.

The example shown in FIG. 16 has a ring-shaped electrode, and is basically the same as the example shown in FIG. 15, and is a modified example thereof.

In the example shown in FIG. 17, one is a ring-shaped electrode and the other is a needle-shaped electrode. The ring-shaped electrode aims to stabilize the generated bubbles, and the needle-shaped electrode aims to improve efficiency by concentrating the electric field.

In the example shown in FIG. 18, one ring-shaped electrode is formed on the wall surface of the thermal energy application section. In addition to the effects of the example shown in FIG. 17, this is aimed at the ease of manufacturing by forming electrodes in a two-dimensional manner on the substrate. A plurality of such planar electrodes can be easily manufactured with high density by vapor deposition (or sputtering) or photoetching techniques. Particularly effective for multi-arrays.

In the example shown in FIG. 19, the ring-shaped electrode forming portion of the example shown in FIG. 18 is shaped along the outer periphery of the electrode and is raised one step higher than the surroundings. Again, the aim is to stabilize the generated bubbles, and the stability is greater than that shown in FIG. 17 by adding a three-dimensional guide.

The example shown in Fig. 20, contrary to the example shown in Fig. 19, has a structure in which the ring-shaped electrode forming part is sunk downward from the periphery, so that the bubbles generated are stable. It is formed by

21 to 28 are diagrams for explaining the control mechanism when the recording head is incorporated into a recording device to actually perform recording. First, referring to FIGS. 21 to 24, Each electrical/thermal converter 1101.11 according to external signals
02. An example will be explained in which liquid is discharged simultaneously from each discharge port 1, 11□, 111□, ......111□ according to an external signal by controlling the ......1107 at the same time. do. First, FIG. 21 is an overall block diagram, in which input signals from computer keyboard operations are input from an interface circuit 121 to a data generator 122. Next, a desired character in the character generator 123 is selected, and the data signals are arranged in the data generator 122 in a form that is easy to print. The data arranged in the data generator 122 is once stored in the buffer circuit 124, and is sequentially stored in the driver circuits 1251-125. and sent to each converter 110□.

110□, . . . 1107 are driven to eject droplets. The control circuit 126 is a circuit that controls the input/output timing of each circuit and outputs a signal instructing the operation of each circuit.

FIG. 22 is a timing chart explaining the operation of the buffer circuit 124 shown in FIG.
A character clock 5101 generated by a character generator generates a data signal 5102 arranged in
At the other timing, output signals are sequentially given to drive circuits 125□ to 125□. In the example of FIG. 21, input/output is performed using one buffer circuit, but control using a plurality of buffer circuits, so-called double buffering, may also be performed. That is, when one buffer circuit is inputting, the other buffer circuit outputs, and at the next timing, each buffer circuit performs the opposite operation. When double buffering is used, droplets can be ejected continuously.

In this way, seven transformers 110. ．． 1102°...
110 are simultaneously controlled according to the droplet ejection timing chart as shown in FIG. 23, and as a result, the second
Printing as shown by circles in FIG. 4 can be performed by ejecting droplets from seven ejection ports. In addition, signals 5111~
Each of A117 has seven converters 110□, 110□,
. . . is a signal applied to each of 1107.

25 to 28 are diagrams for explaining an example of a control mechanism that sequentially controls each electric/thermal converter according to an external signal to sequentially eject droplets from each ejection port. A block diagram of the entire device is shown. In FIG. 25, external signals 5130 pass through interface circuit 131 and are arranged by data generator 132 in an order convenient for printing. In the example shown in FIG. 25, in which data is printed column by column, data is read out from the character generator 133 for each column and temporarily stored in the column buffer circuit 134. Then, at the timing when column data is read from the character generator 133 and input to the column buffer circuit 134□, another data is output from the column buffer circuit 1341, and the drive circuit 135 is operated.

FIG. 26 shows a timing chart explaining the operation of the buffer circuit 134. The column data signal output from the drive circuit 135 is transmitted to each converter 1101, 110□, . . . 110 controlled by the gate circuit 137.
7 are sequentially driven. A timing chart at that time is shown in FIG. In the figure, 5141 is a character clock, 5142 is an input signal to the column buffer circuit 134□, 5143 is an input signal to the column buffer circuit 134°, 5144 is a signal output from the column buffer child circuit 134□, and 5145 is a column Buffer circuit 134□
shows the signal output from. As a result, e.g.
According to the droplet ejection timing as shown in FIG. 7, droplets are sequentially ejected from the seven ejection ports, and characters as shown by circles in FIG. 28 are printed. In addition, signals 5151 to 51
Each of 57 has seven transformers 1101°1102, ・
1107 shows signals applied to each of 1107.

Although the control mechanism has been explained using an example of character printing, the same method is used when obtaining a copy image or the like.

Further, in this example, an example using a print head having seven ejection ports has been described, but it is also possible to perform printing in a similar manner when a full-line multi-orifice type print head is used.

The recording liquid used in the recording device according to the present invention is selected from the materials and the ratios of the composition components are adjusted so as to have the thermophysical properties and other physical properties described below, as well as those used in conventional recording methods. In addition to being chemically and physically stable with the same type of recording liquid, it also has excellent responsiveness, fidelity, and thread-forming ability, does not harden in the liquid path, especially at the discharge port, and can flow in the flow path according to the recording speed. The physical properties are adjusted to give properties such as being able to circulate at a high speed, being quickly fixed on the recording member after recording, having sufficient recording density, and having a good shelf life.

The recording liquid used in the recording device according to the present invention is composed of a liquid medium, a recording agent for forming a recorded image, and an additive added to obtain desired characteristics. Depending on the type and composition ratio of additives, it is possible to obtain either aqueous, non-aqueous, soluble, electrically conductive, or insulating properties.

Liquid media are broadly classified into aqueous media and non-aqueous media, but the liquid media used are those that are combined with other selected constituents so that the recorded recording liquid has the above-mentioned physical properties. The combination is selected from the following.

Such non-aqueous media include, for example, methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, 5ec-butyl alcohol, tert-butyl alcohol, isobutyl alcohol, pentyl alcohol, hexyl alcohol, heptyl alcohol. , C1-C10 alkyl alcohols such as octyl alcohol, nonyl alcohol, and decyl alcohol; For example, hydrocarbon solvents such as hexane, octane, cyclopentane, benzene, toluene, and quidylol; For example, carbon tetrachloride, trichloroethylene, and tetrachloride; Halogenated hydrocarbon solvents such as chloroethane and dichlorobenzene; Ether solvents such as ethyl ether, butyl ether, ethylene glycol diethyl ether, and ethylene glycol monoethyl ether; For example, acetone, methyl ethyl ketone, methyl propyl ketone, methyl amyl ketone, Ketone solvents such as cyclohexanone; ester solvents such as ethyl formate, methyl acetate, propyl acetate, phenyl acetate, and ethylene glycol monoethyl ether acetate; alcohol solvents such as diacetone alcohol;
Examples include petroleum-based hydrocarbon solvents.

These enumerated liquid media are appropriately selected and used so as to satisfy the compatibility with the recording agent and additives used and the various properties described below as a recording liquid. Two or more types may be mixed and used as appropriate within the range in which a recording liquid having the characteristics can be prepared. Moreover, these non-aqueous media and water may be mixed and used within the above conditions.

Among the above-mentioned liquid media, water or water/alcohol-based liquid media are preferred in consideration of pollution, ease of availability, ease of preparation, and the like.

As a recording agent, in addition to ensuring that the recording liquid to be prepared has the above-mentioned physical properties, it also prevents sedimentation and agglomeration in the liquid path and recording liquid supply tank due to long-term storage, as well as rings, pipes, etc. It is necessary to select materials in relation to the liquid medium and additives so as not to cause clogging of the liquid path. From this point of view, it is preferable to use a recording agent that is soluble in the liquid medium, but even if the recording agent is dispersible or poorly soluble in the liquid medium, the particles of the recording agent when dispersed in the liquid medium are・
It can be used if the diameter is made sufficiently small.

The recording material that can be used is appropriately selected depending on the recording member so as to fully suit the recording conditions. Recording agents include dyes and pigments.

The dye that can be effectively used is one that satisfies the properties described below for the prepared recording liquid, and examples of suitable dyes include direct dyes as water-soluble dyes, basic dyes, and acidic dyes. In addition to dyes, soluble vat dyes, acidic mordant dyes, mordant dyes, sulfur dyes as water-insoluble dyes, vat dyes, alcoholic dyes, oil-soluble dyes, disperse dyes, thren dyes, naphthol dyes 1, The dye is selected from reactive dyes, chromium dyes, 1:2 type chloride dyes, 1:1 type complex salt dyes, azoic dyes, cationic dyes, and the like.

Specifically, for example, Resolin Lil Blue PRL, Resolin Yellow PCG, Resolin Pink PRR, Resolin Green PB (manufactured by Bayer) Sumikalon Blue 5-
BG, Sumikaron Red E-EBL, Sumikalon Yellow E-40L, Sumikalon Brilliant Blue 5-BL
(Manufactured by Jumin Chemical), Diamond Mirror Yellow-HG-8
E, Diamond Thread BN-8E (manufactured by Mitsubishi Kasei), Kayalon Polyester Light Flavin 4GL, Kayalon Polyester Blue 3R-8F, Kayalon Polyester Yellow YL-3E, Kaya Set Turquis Blue 776, Kaya Set Yellow 902, Kayaset Red 026, Prodione Red H-2B, Prodione Blue H-3R (manufactured by Nippon Kayaku), Revafix Golden Yellow P-R, Revafix Pril Red P-B
, Revafix Pril Orange P-GR (manufactured by Buyer), Sumifix Yellow GR8, Sumifix B, Sumifix Pril Red BS, Sumifix Pril Blue PB, Direct Black 40 (manufactured by Jumin Chemical), Diamond Mirror Brown 3G, Diamirror Yellow 〇, Diamirror Blue 3R, Diamirror Prill Blue B, Diamirror Prill Red BB (manufactured by Mitsubishi Kasei), Remazol Red B, Remazol Blue 3
R, Remazol Yellow GNL, Remazol Prill Green 6B (manufactured by Hoechst), Cibaclon Prill Yellow, Cibaclon Prill Red 40E (manufactured by Ciba Geigy), Indigo, Direct Tape Black E-
Ex, Diamine Black BH, Congo Red, Serious Black BH, Orange■, Amido Black IOB
, Orange R○, Metaneal Yellow, Pictoria Scarlet, Nigrosine, Diamond Black PBB (
Diacit Blue 3G, Diacit Fast Green GW, Diacito Milling Navy Blue R, Indanthrene (made by Mitsubishi Kasei),
Zapon dye (manufactured by BASF), orazole dye (
(manufactured by CI B A), Lanasin dye (Mitsubishi Kasei N), Diacrylic Orange RL-E, Diacrylic Brilliant Blue 2B-E, Diacrylic Turkis Blue BG-
E (manufactured by Mitsubishi Kasei) and the like, those that provide the recording liquid with the above-mentioned physical properties can be preferably used.

These dyes are appropriately selected as desired and used after being dissolved or dispersed in the liquid medium used.

As pigments that can be effectively used, many of inorganic pigments and organic pigments are suitably used. Specific examples of such pigments include inorganic pigments such as cadmium sulfide, sulfur, selenium, zinc sulfide, cadmium sulfoselenide, yellow lead, zinc chromate, molybdenum red, Guinée green, titanium white, zinc white, and zinc white. Handle, chromium oxide green, red lead, cobalt acid, barium titanate, titanium yellow, iron black, navy blue, litharge, cadmium red, silver sulfide, lead sulfate, barium sulfate, ultramarine blue, calcium carbonate, magnesium carbonate, lead white, Examples include cobalt violet, cobalt blue, emerald green, and carbon black.

Most of the organic pigments are classified as dyes and often overlap with dyes, but specifically, the following types are preferably used.

(,) Insoluble azo type (naphthol type) Brilliant Carmine BS, Lake Carmine FB, Brilliant Fast Scarlet, Lake Red 4R, Rose Red, Permanent Red R, Fast Red FG
R, Lake Bordeaux 5B, Vermilion No. 1, Vermilion No. 2, Toluidine Maroon.

(b) Insoluble azo type (anilide type) Diazo Yellow, Fast Yellow G, Fast Yellow 10G, Diazo Orange, Palkan Orange, Balazolone Red.

(c) Soluble Azo Lake Orange, Brilliant Carmine 3B, Brilliant Carmine 6B, Brilliant Scarlet G, Lake Red C, Lake Red D, Lake Red R, Watching Red, Lake Bordeaux 10B, Bon Maroon L
, Bonmaroon M0 (d) Phthalocyanine-based Phthalocyanine Blue, Fast Sky Blue, Phthalocyanine Green.

(e) Dyeing Lake Yellow Lake, Eosin Lake, Rose Lake, Violet Lake, Blue Lake, Green Lake, Sepia Lake.

(f) Mordant system Alizarin Lake, Madakamine.

(g) Vat-dyed type Industhrene series, Fast Blue Lake (GGS).

(h) Basic dye lake system Rhodamine Lake, Malachite Green Lake.

(i) Acid dye lake type Fast Sky Blue, Quinoline Yellow Lake, Quinacridone type, Dioxazine type.

The quantitative relationship between the liquid medium and the recording agent is determined based on conditions such as clogging of the liquid path, drying of the recording liquid in the liquid path, bleeding when applied to the recording member, and drying speed in addition to the formulation. The recording agent is usually 1 to 50 parts by weight, preferably 3 parts by weight, based on 100 parts of the liquid medium.
~30 parts, optimally 5 to 10 parts.

When the recording liquid is a dispersion system (a system in which the recording agent is dispersed in a liquid medium), the particle size of the dispersed recording agent depends on the type of recording agent, recording conditions, inner diameter of the liquid path, ejection opening diameter, and recording member. It is determined as desired depending on the type of recording agent, but if the particle size is too large, sedimentation of the recording agent particles may occur during storage, resulting in uneven density or clogging of the liquid path. This is undesirable because it may cause density unevenness in the recorded image.

Taking this into consideration, the particle size of the recording agent used as a dispersion recording liquid is usually 0.01 to 30μ, preferably 0.01 to 20μ, and optimally 0.01 to 8μ. It is desirable to Furthermore, the particle size distribution of the dispersed recording agent is preferably as narrow as possible, and is usually D±3μ,
A preferable value is D±1.5μ (where D represents the average particle size).

Examples of the additives used include viscosity modifiers, surface tension modifiers, pH modifiers, resistivity modifiers, wetting agents, infrared absorbing exothermic agents, and the like.

In addition to obtaining the above-mentioned physical property values, the viscosity modifier and surface tension modifier must also be able to flow through the liquid path at a sufficient flow rate depending on the recording speed, and prevent the recording liquid from going around at the discharge port of the liquid path. It is added for the purpose of preventing bleeding (spreading of the spot diameter) when applied to a recording member.

The viscosity modifier and surface tension modifier are selected from commonly known agents as long as they are effective and do not adversely affect the liquid medium and recording material used, so as to satisfy the desired properties. used.

Specifically, viscosity modifiers include polyvinyl alcohol, hydroxypropyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, methyl cellulose, water-soluble acrylic resin, polyvinyl pyrrolidone,
Gum arabic starch and the like can be exemplified as suitable examples.

Surface tension modifiers that are suitably selected and used as desired include anionic, cationic, and nonionic surfactants. Specifically, as anionic surfactants, polyethylene glycol ether sulfate is used as an anionic surfactant. , ester salts, etc., cationic systems such as poly2-vinylpyridine derivatives, poly4-vinylpyridine derivatives, etc., nonionic systems such as polyoxyethylene alkyl ether, polyoxyethylene alkylphenyl ether, polyoxyethylene alkyl ester, polyoxyethylene sorbitan Examples include monoalkyl esters and polyoxyethylene alkylamines.

In addition to these surfactants, there are also amino acids such as jetanolamine, propatoolamine, and morpholinic acid, basic substances such as ammonium hydroxide and sodium hydroxide, and substituted pyrrolidones such as N-methyl-2-pyrrolidone. Used effectively.

These surface tension modifiers do not adversely affect each other or other constituents, and provide the above-mentioned physical properties to the recording liquid being formulated, so that a recording liquid having a desired value of surface tension is formulated. If necessary, two or more types may be mixed and used within the range specified above.

The amount of these surface tension modifiers to be added is determined as appropriate depending on the type, other constituent components of the recording liquid to be prepared, and desired recording characteristics. Usually 0.0001 to 0.1 parts by weight, preferably 0.0001 to 0.1 parts by weight.
The amount is desirably 0.001 to 0.01 parts by weight.

The pH adjuster is used to maintain a predetermined pH value in order to maintain the chemical stability of the prepared recording liquid, for example, to prevent changes in physical properties due to long-term storage and to prevent sedimentation and aggregation of the recording agent and other components. It is added at the right time and in an appropriate amount within a range that does not deviate from the physical property values.

As the pH adjuster suitably used in the present invention,
Almost any pH can be used as long as it can control the pH value to a desired level without adversely affecting the recording liquid being prepared.

Specific examples of such pH adjusters include lower alkanolamines, monovalent hydroxides such as alkali metal hydroxides, and ammonium hydroxide.

These pH adjusters are added in a necessary amount so that the recording liquid to be prepared has a desired pH value within a range that does not deviate from the above-mentioned physical property values.

The lubricant to be used is one that is more effective than those commonly known in the technical field related to the present invention, especially one that is thermally stable, as long as the recording liquid to be prepared does not deviate from the various physical properties listed below. are preferably used. Specific examples of such lubricants include polyalkylene glycols such as polyethylene glycol and polypropylene glycol; alkylene glycols in which the alkylene group has 2 to 6 carbon atoms such as butylene glycol and hexylene glycol; for example, ethylene glycol; Lower alkyl ethers of diethylene glycol such as methyl ether, diethylene glycol methyl ether, and diethylene glycol ethyl ether; Glycerin; Lower alcohol oxytriglycols such as methoxytriglycol and ethoxytriglycol; N-vinyl-2-
Examples include pyrrolidone oligomer; and the like.

These lubricants are added in the required amount as desired so that the recording liquid satisfies the desired characteristics.
The amount added is usually 0.1 to 1% based on the total weight of the recording liquid.
0 wt%, preferably 0.1 to 8 wt%, optimally 0.2
It is desirable that the content be 7 tit%.

In addition to being used alone, the above lubricants may be used in combination of two or more types provided that they do not adversely affect each other.

The recording liquid used in the recording device of the present invention may be added with the above-mentioned additives in required amounts as desired. For example, alkyd resin,
Resin polymers such as acrylic resin, acrylamide resin, polyvinyl alcohol, and polyvinylpyrrolidone may also be added.

The recording liquid used in the recording device of the present invention has specific heat, coefficient of thermal expansion, thermal conductivity, viscosity, surface tension, pH, and charged recording droplets so as to have the various recording properties described above. In the case of recording, it is desirable that the composition be prepared so that the characteristic values such as specific resistance are within the conditional range of the characteristic.

That is, these characteristics have important relationships with the stability of the stringing phenomenon, responsiveness and fidelity to thermal energy effects, image density, chemical stability, fluidity within the liquid path, etc. Therefore, in the present invention, it is necessary to pay sufficient attention to these matters when preparing the recording liquid.

It may be desirable that the above-mentioned properties of the recording liquid that can be effectively used in the recording device of the present invention be as shown in Table 1 below, but all of the listed physical properties are as shown in Table 1. It is not necessary to satisfy the numerical conditions shown in Table 1, but it is sufficient that some of these physical properties take values that satisfy the conditions shown in Table 1, depending on the required recording characteristics. It is desirable that the specific heat, thermal expansion coefficient, thermal conductivity, viscosity, and surface tension be defined by the values shown in Table 1. Of course, it goes without saying that the more of the above-mentioned properties of the prepared recording liquid that satisfy the values shown in Table 1, the better the recording will be.

-50= Table 1 As is clear from the above description, according to the present invention, 1. Clogging can be prevented by providing a filter.

2. By providing the filter within the liquid chamber or on the upstream side of the liquid chamber, insufficient ink supply due to the fluid resistance of the filter can be prevented.

3. By making the opening cross-sectional area Si of the portion where the flow path and the liquid chamber communicate with each other equal to or larger than the opening cross-sectional area So of the orifice, insufficient ink supply to the flow path can be prevented.

Therefore, the recording liquid can be ejected at high speed without clogging.

[Brief explanation of the drawing]

FIG. 1 is a main part configuration diagram for explaining an embodiment of the present invention, in which (a) is a cross-sectional view of the head, (b) is a planar cross-sectional view of the head, and FIG. 3 is a diagram for explaining the operation of a bubble jet head as an example of an inkjet head to which the present invention is applied. FIG. 4 is a perspective view showing an example of a bubble jet head. 5 is an exploded perspective view, FIG. 6 is a view of the lid substrate seen from the back side, FIG. 7 is a diagram for explaining details of the bubble jet recording head, and FIG. 8 is a heating resistor. 9 is a block diagram illustrating an example of a heating element driving circuit, and FIG. 10 is a diagram illustrating the structure of a bubble generating means using a laser beam. A diagram for explaining an example, FIG. 11 is a diagram for explaining an example of a printer, FIG. 12 is a diagram for explaining an example of a bubble generating means using electric discharge, and FIGS. The figures show specific examples of the discharge electrodes shown in Fig. 12, and Figs. 21 to 24 and 25 to 28 respectively show recording when the recording head is incorporated into a recording device. FIG. 29, which is a diagram for explaining an example of control when performing this, is a diagram for explaining the prior art. 1... Head part, ■... Channel part, 2... Recording liquid,
3... Air bubbles, 4... Heating element, 5... Filter. 1 (a) 3rd ヱ1 9th:- Figure 10 Figure 12, 1. + 25 ・ 110r 26th L4 Fig. 29

Claims (1)

[Claims] 1. A flow path that accommodates the recording liquid to be introduced and is provided with a thermal energy acting section that generates bubbles in the recording liquid by heat and generates an acting force as the volume of the bubbles increases; an orifice that communicates with the flow path to eject the recording liquid as a droplet by the acting force; a liquid chamber that communicates with the flow path and introduces the recording liquid into the flow path; A liquid jet recording head comprising a means for introducing liquid, the liquid jet recording head having at least one filter means in the liquid chamber or upstream of the liquid chamber, and in which the liquid flow in a portion where the flow path and the liquid chamber communicate with each other. A liquid jet recording head characterized in that the opening cross-sectional area of the channel is equal to or larger than the opening cross-sectional area of the orifice.