JP2614265B2 - Liquid jet recording head - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a liquid jet recording head, and more particularly, to a structure of a head portion of a multi-array high-speed bubble jet printer.

2. Description of the Related Art Non-impact recording methods have recently attracted attention in that the generation of noise during recording is extremely small to a negligible level. Among them, the so-called ink jet recording method, which can perform high-speed recording and can perform recording on so-called plain paper without requiring a special fixing process, is an extremely powerful recording method. Some have been proposed and commercialized with improvements, while others are still being put to practical use.

In such an ink jet recording method, recording is performed by flying droplets of a recording liquid called so-called ink and attaching the droplets to a recording member. The control method for controlling the flying direction of the generated recording liquid droplet is roughly classified into several types.

First, the first system is, for example, a system disclosed in US Pat. No. 3,060,429 (Tele type system), in which droplets for recording are generated by electrostatic attraction, and the generated recording liquid droplets are subjected to an electric field according to a recording signal. The recording is performed by controlling the recording liquid droplets to selectively adhere to the recording member.

More specifically, in more detail, an electric field is applied between the nozzle and the accelerating electrode to discharge a uniformly charged droplet of the recording liquid from the nozzle, and the discharged droplet of the recording liquid is converted into a recording signal. In accordance with this, recording is performed by causing the droplets to fly between the xy deflection electrodes configured so as to be electrically controllable and selectively adhering small droplets onto the recording member by a change in the intensity of the electric field.

The second method is a method (Sweet method) disclosed in, for example, US Pat. No. 3,596,275, US Pat. No. 3,298,030, in which a droplet of a recording liquid whose charge amount is controlled by a continuous vibration generation method is generated, and the generated charging is performed. The recording is performed on the recording member by causing the controlled amount of the droplet to fly between the deflection electrodes to which a uniform electric field is applied.

More specifically, a charging electrode configured so that a recording signal is applied in front of an orifice (ejection port) of a nozzle, which is a part of a recording head provided with a piezoelectric vibrating element, is separated by a predetermined distance. The piezoelectric vibrating element is mechanically vibrated by applying an electric signal of a constant frequency to the piezoelectric vibrating element, and a droplet of the recording liquid is discharged from the discharge port. At this time, a charge is electrostatically induced in the recording liquid droplet discharged by the charging electrode, and the droplet is charged with a charge amount according to the recording signal. When the droplet of the recording liquid whose charge amount is controlled flies between the deflection electrodes to which a constant electric field is uniformly applied, the droplet is deflected according to the added charge amount and carries a recording signal. Only the recording material can be deposited on the recording member.

The third method is a method (Hertz method) disclosed in, for example, US Pat. No. 3,416,153, in which an electric field is applied between a nozzle and a ring-shaped charging electrode to generate and atomize small droplets of a recording liquid by a continuous vibration generation method. This is the method of recording. That is, in this method, the atomization state of the small droplet is controlled by modulating the electric field intensity applied between the nozzle and the charging electrode in accordance with the recording signal, and the image is recorded with the gradation of the recorded image.

The fourth method is, for example, a method (Stemme method) disclosed in US Pat. No. 3,747,120. This method is fundamentally different from the above three methods in principle.

That is, in each of the three methods, the droplet of the recording liquid discharged from the nozzle is electrically controlled during the flight, and the droplet carrying the recording signal is selectively attached to the recording member. On the other hand, according to the Stemme method, recording is performed by ejecting a small droplet of recording liquid from an ejection port in accordance with a recording signal.

That is, in the Stemme method, the piezoelectric vibrating element attached to the recording head having the ejection port for ejecting the recording medium includes:
Applying an electrical recording signal, converting the electrical recording signal into mechanical vibration of a piezo-vibrating element, and ejecting a droplet of the recording liquid from the ejection port in accordance with the mechanical vibration to cause the droplet to fly and adhere to the recording member. Is to record.

Each of these four conventional methods has its own features, but on the other hand, there are points that can be solved.

That is, in the first to third methods, the direct energy of the generation of the droplet of the recording liquid is electric energy,
Droplet deflection control is also electric field control. Therefore, the first method is simple in structure, but requires a high voltage to generate small droplets, and is not suitable for high-speed printing because it is difficult to use a multi-nozzle recording head.

The second method enables multi-nozzle recording heads and is suitable for high-speed recording. However, the method is complicated in structure, and the electrical control of small droplets of recording liquid is difficult and difficult. Are liable to occur.

The third method has a feature that an image having excellent gradation can be recorded by atomizing a recording liquid droplet, but on the other hand, it is difficult to control the atomization state, and fogging occurs in the recorded image. In addition, there are various problems such as the fact that it is difficult to form a multi-nozzle recording head and that it is not suitable for high-speed recording.

The fourth scheme has relatively many advantages over the first to third schemes. That is, in order to perform recording by discharging the recording liquid from the discharge port of the nozzle on demand (on-demand), it is simple in terms of the configuration. It is not necessary to collect small droplets that are not required for recording an image, and there is no need to use a conductive recording liquid as in the first and second methods, and the recording liquid material Has a great advantage such as a large degree of freedom. However, on the other hand, it is difficult to form a multi-nozzle recording head because there are problems in processing the recording head and it is extremely difficult to reduce the size of the piezoelectric vibrating element having a desired resonance number. However, since the recording medium droplets are ejected and fly by the mechanical energy of mechanical vibration of the piezo-vibration element, it is not suitable for high-speed recording.

Furthermore, Japanese Patent Application Laid-Open No. 48-9622 (corresponding to the above-mentioned US Pat. No. 3,747,120) describes, as a modification, the use of thermal energy instead of the mechanical vibration energy by means such as the piezo-vibration element. Have been.

That is, the above-mentioned publication describes a so-called bubble jet liquid jet recording apparatus which uses a heating coil for directly heating a liquid as a pressure increasing means instead of a piezo vibrating element in order to generate vapor which causes a pressure increase. I have.

However, the above publication discloses that a heating coil serving as a pressure increasing means is energized to directly evaporate the liquid ink in a bag-shaped ink chamber (liquid chamber) having only one opening through which the liquid ink can enter and exit. However, there is no suggestion as to how to heat the liquid when the liquid is continuously and repeatedly discharged. In addition, since the position where the heating coil is provided is provided at the deepest part of the bag-shaped liquid chamber far from the supply path of the liquid ink, in addition to being complicated in terms of the head structure, continuous It is not suitable for repeated use.

In addition, according to the technical contents described in the above-mentioned publication, it is not possible to quickly form a preparation state for the next droplet discharge after the liquid is discharged by the generated heat which is practically important.

As described above, the conventional method has advantages and disadvantages in terms of configuration, high-speed recording, multi-nozzle recording head, generation of satellite dots and occurrence of fogging of a recorded image, etc. There was a restriction that only the application was possible.

In view of the above points, the applicant of the present application has proposed that a clear recording that is structurally thimble, facilitates multi-nozzle formation, enables high-speed recording, does not generate satellite dots, and has no fog. A liquid jet recording method capable of obtaining an image was proposed (Japanese Patent Publication No. 56-9429).
This is the basis of a so-called bubble jet type ink jet recording apparatus in which bubbles are generated in ink and ink droplets are ejected from an orifice by the action force of the bubbles.

FIG. 2 is a view 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. 3 is a perspective view showing an example of a bubble jet head, and FIG. A lid substrate (FIG. 4 (a)) and a heating element substrate (FIG. 4 (b)) which constitute the head shown in FIG.
FIG. 5 is a perspective view of the lid substrate shown in FIG. 4 (a) viewed from the back side, where 1 is a lid substrate;
2 is a heating element substrate, 3 is a recording liquid inlet, 4 is an orifice, 5 is a flow path, 6 is a region for forming a liquid chamber, 7 is an individual (independent) electrode, 8 is a common electrode, and 9 is a heating element. (Heater), 10 is ink, 11 is bubbles, and 12 is flying ink droplets. The present invention is applied to such a bubble jet type liquid jet recording head.

First, the ink ejection by the bubble jet will be described with reference to FIG. 2. (a) is a steady state, and the surface tension of the ink 10 and the external pressure are in an equilibrium state at the orifice surface.

6B shows a state in which the heater 9 is heated until the surface temperature of the heater 9 rises rapidly and boiling development occurs in the adjacent ink layer, and minute bubbles 11 are scattered.

FIG. 3C shows a state in which the adjacent ink layer rapidly heated on the entire surface of the heater 9 is instantaneously vaporized to form a boiling film, and the bubbles 11 grow. At this time, the pressure in the nozzle rises by an amount corresponding to the growth of the bubble, the balance with the external pressure on the orifice surface is lost, and the ink column starts to grow from the orifice.

(D) is a state in which the bubbles have grown to the maximum, and the ink 10 corresponding to the volume of the bubbles is pushed out from the orifice surface. At this time, no current is flowing through the heater 9, and the surface temperature of the heater 9 is decreasing. Air bubbles 11
The maximum value of the volume is slightly delayed in the timing of applying the electric pulse.

(E) shows a state in which the bubble 11 is cooled by ink or the like and starts to contract. At the front end of the ink column, the ink moves forward while maintaining the pushed speed, and at the rear end, the ink flows backward from the orifice surface into the nozzle due to a decrease in the nozzle internal pressure due to the contraction of the bubble, and the ink column is constricted. .

(F) is a state in which the bubble 11 is further contracted, the ink comes into contact with the heater surface, and the heater surface is more rapidly cooled. At the orifice surface, the external pressure is higher than the internal pressure of the nozzle, so that the meniscus largely enters the nozzle. The tip of the ink column becomes a droplet and moves in the direction of the recording paper.
Flying at a speed of 10m / sec.

(G) is a process in which the ink is supplied (refilled) to the orifice again by capillary action and returns to the state of (a).
The bubbles have completely disappeared.

FIG. 6 is a view showing a typical example for explaining a main part configuration of the liquid jet recording head as described above. FIG. 6 (a) is a detailed front partial view of the bubble jet recording head viewed from the orifice side. , FIG. 6 (b)
FIG. 3A is a partial cross-sectional view when cut along a portion indicated by a chain line XX in FIG.

The recording head 21 shown in these figures is provided with a predetermined number of grooves having a predetermined linear density and a predetermined width and depth on a substrate 23 provided with an electrothermal transducer 22 on its back surface. Grooved plate
By joining the substrate 24 so as to cover the substrate 23, a liquid ejection portion 26 including an orifice 25 for flying a liquid is formed. The liquid discharge section 26 has an orifice
The thermal energy generated by the thermal energy generated by the electrothermal converter 25 and the electrothermal converter 22 generates bubbles by causing a rapid change in state due to expansion and contraction of the volume of the liquid.
And

The heat acting portion 27 is located above the heat generating portion 28 of the electrothermal converter 22 and has a heat acting surface 29 serving as a surface of the heat generating portion 28 in contact with the liquid as a bottom surface. The heat generating section 28 includes a lower layer 30 provided on the base 23, a heating resistor layer 31 provided on the lower layer 30, and an upper layer 32 provided on the heating resistor layer 31.

On the surface of the heating resistance layer 31, electrodes 33 and 34 for supplying electricity to the layer 31 to generate heat are provided on the surface thereof.
A heat generating portion 28 is formed by the heat generating resistance layer between these electrodes.

The electrode 33 is an electrode common to the heat generating unit of each liquid discharging unit, and the electrode 34 is a selection electrode for selecting the heat generating unit of each liquid discharging unit to generate heat, and It is provided along the flow path.

The protective layer 32 forms the heat generating resistance layer 31 in the heat generating portion 28,
In order to protect the used liquid chemically and physically, the heating resistance layer 31 is isolated from the liquid filling the liquid flow path of the liquid discharge section 26, and a short circuit between the electrodes 33 and 34 through the liquid is prevented. It has a function of preventing the occurrence of electric leakage between adjacent electrodes.

The liquid flow paths provided in each of the liquid discharge sections are communicated upstream of each of the liquid discharge sections via a common liquid chamber (not shown) constituting a part of the liquid flow path. Electrodes 33 and 34 connected to the electrothermal converter 22 provided in each liquid discharge section are protected by the upper layer and pass under the common liquid chamber on the upstream side of the heat acting section due to the design convenience. It is provided to pass through.

In such a liquid jet recording head, conventionally, as shown in FIG. 6, an electrothermal transducer is provided on a heating resistor layer laminated in a predetermined shape on one surface of a substrate 23, with a predetermined shape. The electrode layer having a shape includes a pair of electrodes 33, 34 (common electrodes 33, 34).
The heat generating portion 28 made of the heating resistor layer connected between the selection electrodes 34) is laminated and formed so as to be arranged at a predetermined position on the substrate. Therefore, the common electrode 33 has a folded shape, and the common electrodes 33 and the selection electrodes 34 are alternately arranged. Therefore, the plurality of heat generating portions are arranged so as to sandwich the common electrode.

FIG. 7 is a detailed view for explaining the structure of a bubble generating means using a heating resistor. In the drawing, 41 denotes a heating resistor, 42 denotes an electrode, 43 denotes a protective layer, and 44 denotes a power supply device. Resistor 41
As the material constituting the, the useful, for example, a mixture of tantalum -SiO _2, tantalum nitride, nichrome, silver -
Examples include palladium alloys, silicon semiconductors, and borides of metals such as hafnium, lanthanum, zirconium, titanium, tantalum, tungsten, molybdenum, niobium, chromium, and vanadium.

Among these materials constituting the heating resistor 41, metal borides can be mentioned as being particularly excellent, and among them, hafnium boride has the most excellent characteristics.
Next are zirconium boride, lanthanum boride, tantalum boride, vanadium boride, and niobium boride.

The heat generating resistor 41 can be formed using the above-mentioned materials by a technique such as electron beam evaporation or sputtering. The film thickness of the heating resistor 41 is determined according to its area, material, shape and size of the heat acting portion, and furthermore, power consumption in an actual plane, so that the amount of heat generated per unit time is as desired. , But usually 0.001-5μ
m, preferably 0.01 to 1 μm.

As the material constituting the electrode 42, many commonly used electrode materials are effectively used, and specifically,
For example, Al, Ag, Au, Pt, Cu and the like can be mentioned, and these are used to be provided at a predetermined position in a predetermined size, shape and thickness by a method such as vapor deposition.

The characteristics required for the protective layer 43 do not prevent the heat generated by the heating resistor 41 from being effectively transmitted to the recording liquid,
This means that the heating resistor 41 is protected from the recording liquid. Useful materials for forming the protective layer 43 include, for example, silicon oxide, silicon nitride, magnesium oxide, aluminum oxide, tantalum oxide, zirconium oxide, and the like. Can be formed. Protective layer
The film thickness of 43 is usually 0.01 to 10 μm, preferably 0.1 to 5 μm.
m, optimally 0.1 to 3 μm.

The recording head prepared as described above is pulsed to the electric / thermal converter in accordance with an image signal while supplying the recording liquid at such a pressure that the recording liquid does not discharge from the discharge port when the heating resistor does not generate heat. When recording was performed by applying a voltage, a clear image was obtained.

FIG. 8 is a block diagram showing an example of a heating element driving circuit at that time. Reference numeral 51 denotes a well-known reading optical input photosensor unit including a photodiode or the like. The input image signal is processed by a processing circuit 52 including a circuit such as a comparator and the like.
Entered in 53. The drive circuit 53 drives the recording head 54 by controlling the pulse width, pulse amplitude, repetition frequency and the like according to the input signal.

For example, in the simplest recording, the processing circuit 52 discriminates the input image signal between black and white and inputs the signal to the drive circuit 53.
In the drive circuit 53, a pulse width for obtaining an appropriate droplet diameter,
The repetition frequency for obtaining the desired recording droplet density is converted into a controlled signal, and the recording head 54 is driven.

Further, as another recording method in consideration of gradation, one method is to perform recording in which the droplet diameter is changed, and another method is to perform recording in which the number of recording droplets is changed as follows. You can also.

First, in the recording method for changing the droplet diameter, an image signal input by the optical input photosensor unit 51 is a drive signal having a pulse width and a pulse amplitude of each level determined to obtain a desired droplet diameter. Drive circuit 53 having a plurality of circuits for outputting
The processing circuit 52 determines which level of the signal is to be output by the processing circuit 52 and processes the signal. In the method of changing the number of recording droplets, an input signal to the optical input photosensor unit 51 is A / D converted and output by the processing circuit 52, and the drive circuit 53 outputs one input signal according to the output signal. A signal for driving the recording head 54 is output so that recording is performed while changing the number of ejected droplets per hit.

In another embodiment, a similar device is used to supply the recording liquid to the recording head 54 at a pressure higher than the pressure at which the recording liquid overflows from the ejection port without generating heat from the heating resistor. When recording was performed by applying a voltage to the body with a continuous repetitive pulse, it was confirmed that droplets of a number corresponding to the applied frequency were stably ejected with a uniform diameter.

From this point, it has been found that the recording head 54 is very effectively applied to continuous ejection at a high frequency.

Further, since the recording head, which is a 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 can be realized.

FIG. 9 is a view for explaining means for generating bubbles in the recording liquid by using a pulse laser. In the figure, 61 is a laser oscillator, 62 is an optical modulation drive circuit, 63 is an optical modulator, and 64 is a scan. And 65 is a condensing lens, and the laser light generated by the laser oscillator 61 is transmitted to the optical modulator 63 by the optical modulator driving circuit.
Pulse modulation is performed in accordance with an image information signal that is input to 62, is electrically processed, and is output. The pulse-modulated laser light passes through a scanner 64 and is condensed by a condenser lens 65 so as to be focused on the outer wall of the thermal energy action section, heats the outer wall 66 of the recording head, and moves the recording liquid 67 inside. To generate air bubbles. Alternatively, the wall 66 of the thermal energy action section is made of a material that is permeable to laser light, and is focused by the condenser lens 65 so that the recording liquid 67 inside is focused, and the recording liquid is directly heated. May generate bubbles.

FIG. 10 is a view for explaining an example of a printer using the laser beam as described above. The nozzle portion 71 has a high density (for example, 8 nozzles / mm) and a paper width (for example, A
4 width) shows an example in which the components are integrated so as to cover the entirety.

The laser light emitted from the laser oscillator 61 is applied to an optical modulator.
Guided to 63 entrance openings. In the optical modulator 63, the laser light is subjected to intensity modulation in accordance with an image information input signal to the optical modulator 63. The optical path of the modulated laser light is bent by the reflecting mirror 68 in the direction of the beam expander 69, and enters the beam expander 69. The beam diameter is expanded by the beam expander 69 while keeping the parallel light.
Next, the laser beam having the expanded beam diameter is incident on a rotating polygon mirror 70 that rotates at a high speed and a constant speed. The laser light swept by the rotating polygon mirror 70 forms an image on the outer wall 66 of the thermal energy action section of the drop generator or on the recording liquid inside by the condenser lens 65. As a result, air bubbles are generated in each of the thermal energy application sections, and the recording liquid droplets are ejected to perform recording on the recording paper 72.

FIG. 11 is a view showing still another bubble generating means. In this example, a pair of discharge electrodes 80 arranged on the inner wall side of the thermal energy action section receives a high voltage pulse from a discharge device 81,
A discharge is generated in the recording liquid, and bubbles are instantaneously formed by heat generated by the discharge.

12 to 19 are diagrams showing specific examples of the discharge electrode shown in FIG. 11, respectively.The example shown in FIG. Discharge (at low energy).

In the example shown in FIG. 13, two flat electrodes are used so that air bubbles are stably generated between the electrodes. The position of the generated bubble is more stable than the needle-shaped electrode.

In the example shown in FIG. 14, a substantially coaxial hole is formed in the electrode. Both holes of the two electrodes serve as guides, and the position of the generated bubbles is further stabilized.

The example shown in FIG. 15 is a ring-shaped electrode, and is basically the same as the example shown in FIG. 14, and is a modified embodiment thereof.

In the example shown in FIG. 16, one is a ring-shaped electrode and the other is a needle-shaped electrode. The ring-shaped electrode aims at stability of generated bubbles, and the needle-shaped electrode aims at efficiency by concentrating an electric field.

In the example shown in FIG. 17, one ring-shaped electrode is formed on the wall surface of the thermal energy action section. This aims at facilitating the production of forming the electrodes in a plane on the substrate in addition to the effect of the example shown in FIG. A plurality of such planar electrodes having high density can be easily manufactured by vapor deposition (or sputtering) or photo-etching technology. Especially effective for multi-array.

In the example shown in FIG. 18, the ring-shaped electrode forming portion of the example shown in FIG. 17 is formed along the outer periphery of the electrode and is raised one step from the periphery. Again, the stability of the generated bubbles is aimed at, and it is more stable than that shown in FIG. 16 by adding a three-dimensional guide.

In the example shown in FIG. 19, in contrast to the example shown in FIG. 18, the ring-shaped electrode forming portion has a structure that is dropped down from the periphery, and again, the generated bubbles are formed stably. Is done.

FIGS. 20 to 27 are views for explaining a control mechanism when the recording head is incorporated in a recording apparatus and recording is actually performed. First, referring to FIGS. 20 to 23, FIG. each electric-heat converter in accordance with an external signal 110 _1, 110 _2, ... 110 ₇ simultaneously controlling the respective discharge ports 111 _1, 111 _2, in the case of performing a liquid discharge in response to an external signal simultaneously ... 111 ₇ An example will be described. First, FIG. 20 is an overall block diagram, in which an input signal 120 by a keyboard operation of a computer is 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 signal is arranged by the data generator 122 in a form easy to print. The data arranged in the data generator 122 is stored in the buffer circuit 1
Is once stored in 24, sequentially, the drive circuit 125 ₁ -125 ₇ sent by each conversion pair 110 _1, 110 _2, drives ...... 110 _7, discharges droplets. The control circuit 126 is a circuit that controls the input / output timing of each circuit and outputs a signal that commands the operation of each circuit.

FIG. 21 is a timing chart for explaining the operation of the buffer circuit 124 shown in FIG.
As shown in FIG. 1, a data signal S102 arranged by a data generator 122 is input in timing with a character clock S101 generated by a character generator, and at the other timing, the drive circuits 125 ₁ to
Giving an output signal to 125 _7. In the example of FIG. 20, input and output are performed by one buffer circuit, but control by a plurality of buffer circuits, so-called double buffering, may be performed. In other words, a method may be adopted in which when one buffer circuit is inputting, the other buffer circuit outputs the signal, and at the next timing, the opposite operation is performed in each buffer circuit. In the case of using a double buffer, droplets can be continuously discharged.

In this way, the seven converters 110 ₁ , 110 ₂ ,... 110 ₇ are simultaneously controlled in accordance with, for example, a droplet discharge timing chart as shown in FIG. 22, and as a result, are indicated by a circle in FIG. Note can be carried out with a liquid droplet ejecting such printing of seven ejection openings, each signal S111~S117 are seven converter 110 _1, 110 _2, signals applied to each of the ...... 110 ₇ It is.

24 to 27 are diagrams for explaining an example of a control mechanism for sequentially controlling each electric-to-heat converter according to an external signal and sequentially discharging droplets from each discharge port. A block diagram of the entire apparatus is shown. In FIG. 24, the external signals S130 pass through the interface circuit 131 and are arranged in an order that allows easy printing by the data generator 132. In the example shown in FIG. 24 where printing is performed for each column, the character generator 133 is used for each column.
, And temporarily store the data in the column buffer circuit 134. Then at a timing that is input to the column buffer circuit 134 ₂ Read column data from the character generator 133, another data is output from the column buffer circuits 134 _1, drive circuit 135 is operated.

FIG. 25 is a timing chart illustrating the operation of the buffer circuit 134. Column data signal outputted from the drive circuit 135 each converter 110 _1, 110 ₂ which is controlled by a gate circuit 137, ... 110 ₇ are successively driven. FIG. 25 shows a timing chart at that time. In FIG, S141 is character clock, the input signal to Koramubafa circuit 134 ₁ S142, S143 the column buffer circuits 134 ₂
Input signals to, S144 is a signal output from the column buffer circuits 134 _1, S145 denotes a signal output from the column buffer circuit 134 _2. As a result, for example, the droplets are sequentially discharged from the seven discharge ports in accordance with the droplet discharge timing as shown in FIG. 26, and the characters indicated by the circles in FIG. 27 are printed. Note that each signal S151~S157 are seven converter 110 _1, 110 _2, shows the signals applied to each of the ...... 110 _7.

Although the control mechanism has been described with the example of printing characters, the same method is used to obtain a copy image or the like. In this embodiment, an example in which a print head having seven discharge ports is used has been described. However, printing can be performed in the same manner when a full-line multi-orifice type print head is used.

The recording medium used in the recording apparatus according to the present invention is used in a conventional recording method in addition to the selection of materials and the ratio of compositional components so as to have a thermophysical property value and other physical property values described below. In addition to being chemically and physically stable like the recording liquid, it has excellent responsiveness, fidelity, and spinning ability, does not harden at the liquid path, especially at the discharge port, and responds to the recording speed in the flow path. The physical properties are adjusted so as to give characteristics such as being able to circulate at a high speed, fast fixing to a recording member after recording, sufficient recording density, and good storage life.

The recording liquid used in the recording apparatus according to the present invention is composed of a liquid medium, a recording agent that forms a recording image, and an additive that is added to obtain desired characteristics. Any of aqueous, non-aqueous, soluble, conductive, and insulating can be obtained by selecting the type of the additive and the composition ratio of the additive.

The liquid medium is roughly classified into an aqueous medium and a non-aqueous medium, and the liquid medium used is a combination of other selected components such that the recording medium whose physical properties are adjusted has the above-mentioned physical properties. Is selected in consideration of the following.

Such non-aqueous media include, for example, methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, tert-butyl alcohol, isobutyl alcohol, pentyl alcohol, hexyl alcohol, heptyl alcohol , Octyl alcohol, nonyl alcohol, alkyl alcohols having 1 to 10 carbon atoms such as decyl alcohol; for example, hydrocarbon solvents such as hexane, octane, cyclopentane, benzene, toluene and xylol; for example, carbon tetrachloride, trichloroethylene,
Halogenated hydrocarbon solvents such as tetrachloroethane 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 , Cyclohexanone and the like; ketone solvents such as ethyl formate, methyl acetate, propyl acetate, phenyl acetate and ethylene glycol monoethyl ether acetate; alcohol solvents such as diacetone alcohol; petroleum hydrocarbon solvents and the like. Can be

These enumerated liquid media are appropriately selected and used so as to satisfy the affinity for a recording agent or an additive to be used and various properties described below as a recording medium. If necessary, two or more kinds may be mixed and used as long as a recording medium having characteristics can be prepared. Further, these non-aqueous media and water may be mixed and used under the above conditions.

Among the above liquid media, water or a water-alcohol-based liquid medium is preferable in consideration of pollution, availability, ease of preparation, and the like.

As the recording agent, the recording liquid to be prepared has the above-mentioned various physical property values, sedimentation and coagulation in a liquid path or a recording liquid supply tank after being left for a long time, and further, a transport pipe or a liquid path. It is necessary to select and use materials in relation to the liquid and additives so as not to cause clogging. From such a point, it is preferable to use a recording agent that is soluble in the liquid medium, but even if the recording agent is dispersible or hardly soluble in the liquid medium, the particles of the recording agent when dispersed in the liquid medium are used. It can be used if the diameter is made sufficiently small.

The recording agent that can be used is appropriately selected depending on the recording member so as to sufficiently meet the recording conditions. Dyes and pigments can be mentioned as recording agents. Dyes to be effectively used are those which can satisfy the following properties of the prepared recording medium, and are preferably used, for example, direct dyes as basic dyes, basic dyes and acid dyes as water-soluble dyes. In addition to dyes, soluble vat dyes, acid mordant dyes, mordant dyes, sulfur dyes as water-insoluble dyes, vat dyes, alcohol-soluble dyes, oil-soluble dyes, disperse dyes, etc., slen dyes, naphthol dyes, reactions Dye, chrome dye, 1: 2 type complex salt dye, 1: 1 type complex salt dye,
It is selected from azoic dyes, cationic dyes and the like.

Specifically, for example, Resoringril Blue PRL, Resorin Yellow PCG, Resorin Pink PRR, Resorin Green PB (manufactured by Buyer), Sumicaron Blue S-BG, Sumicaron Red E-EBL, Sumicaron Yellow E-4GL ,
Sumicaron Brilliant Blue S-BL (Sumitomo Chemical), Dyanix Yellow-HG-SE, Dyanic Thread BN-SE (Mitsubishi Chemical), Kayaron Polyester Light Flavin 4GL, Kayaron Polyester Blue 3
R-SF, Kayaron Polyester Yellow YL-SE, Kayaset Turkey 776, Kayaset Yellow 902, Kayaset Red 026, Prosion Red H-2B, Prosion Blue H-3R (all manufactured by Nippon Kayaku), Levafix Golden Yellow PR, Levafix Brill Red PB, Levafix Brill Orange P-GR (all made by buyers), Sumifix Yellow GRS, Sumifix B, Sumifix Brill Red BS, Sumifix Brill Blue PB, Direct Black 40 (Sumitomo Chemical), Diamond Mirror Brown 3G, Diamond Mirror Yellow G, Diamond Mirror Blue 3R, Diamond Mirror Brill Blue B, Diamond Mirror Brill Red BB (Mitsubishi Chemical), Remazol Red B, Remazol Blue 3R , Remazol Yellow GNL, Remazol Brillg 6B (from Hoechst), Cibacron Brill Yellow, Cibacron Brill Red 4GE (from Ciba Geigy), Indico, Direct Tape Black E / Ex, Diamine Black BH, Congo Red, Serious Black BH, Orange II , Amido Black 10B, Orange RO, Methanyl Yellow, Victoria Scarlet, Nigrosine, Diamond Black PBB (all manufactured by EAG), Diacid Blue 3G, Diacid Fast Green GW, Diacid Milling Navy Blue R. Indanthrene ( Above-mentioned Mitsubishi Kasei), Pomelo-dye (manufactured by BASF), Orazole dye (manufactured by CIBA), Ranacin-dye (manufactured by Mitsubishi Kasei), diacryl orange RL-E, diacryl brilliant blue 2BE, diacryl turquoise blue Before inside BG-E (Mitsubishi Chemical) Those given to the recording liquid in which the various physical property values are prepared can be preferably used.

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

As pigments to 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, graphite, zinc chromate, molybdenum red, Guinea green, titanium white, zinc white, and valve. Pattern, chrome oxide green, lead red, cobalt acid, barium titanate, titanium yellow, iron black, dark blue, litharge, cadmium red, silver sulfide, lead sulfate, barium sulfate, ultramarine, calcium carbonate, magnesium carbonate, lead white, Examples thereof include cobalt violet, cobalt blue, emerald green, and carbon black.

As organic pigments, most of them are classified as dyes and often overlap with dyes. Specifically, the following are preferably used.

(A) Insoluble azo diameter (naphthol type) Brilliant Carmine BS, Lake Carmine FB, Brilliant Fast Scar Red, Lake Red 4R, Para Red, Permanent Red R, Fast Red FGR, Lake Bordeaux 5B, Vermillion NO.1, Vermillion NO .
2, Toluidine maroon.

(B) Insoluble azo (anilide) diazo yellow, fast yellow G, fast yellow 10G, diazo orange, vulcan orange, and parazolone 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 10R, Bonmaroon L, Bonmaroon M.

(D) Phthalocyanine-based phthalocyanine blue, fast sky blue, phthalocyanine green.

(E) Dye lake system Yellow lake, Eosin lake, Rose lake, Biored lake, Blue lake, Green lake, Sepia lake.

(F) Mordant Alizarin lake, Madakamin.

(G) Vat dye-based Induslen based 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 by conditions such as clogging of the liquid path, drying of the recording medium in the liquid path, and bleeding and drying speed when applied to the recording member, in addition to being prepared. The recording agent is usually 1 to 50 parts, preferably 3 to 3 parts by weight per 100 parts of the liquid medium.
It is desirable to use 0 parts, optimally 5 to 10 parts.

When the recording medium 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 the recording agent, the recording conditions, the inner diameter of the liquid path, the ejection port diameter, and the recording member. If the particle size is too large, sedimentation of the recording agent particles will occur during storage, resulting in uneven concentration and clogging of the liquid path. It is not preferable because density spots occur on the recorded image or the recorded image.

In consideration of this, the particle size of the recording agent when the dispersion recording liquid is used is usually 0.01 to 30μ, preferably 0.
It is desirable that the thickness be from 01 to 20 μ, and most preferably from 0.01 to 8 μ.
Further, the particle size distribution of the dispersed recording agent is preferably as narrow as possible, usually D ± 3μ, preferably D ± 1.
Desirably, it is set to 5 μ (where D represents an average grain system).

Examples of the additives used include a viscosity adjuster, a surface tension adjuster, a pH adjuster, a resistivity adjuster, a wetting agent, and an infrared absorbing exothermic agent.

The viscosity adjuster and the surface tension adjuster, in addition to obtaining the above physical property values, can flow through the liquid path at a sufficient flow rate according to the recording speed, and wrap around the recording medium at the discharge port of the liquid path. It is added for the purpose of preventing the occurrence of bleeding (expansion of the spot diameter) when applied to the recording member.

As the viscosity modifier and the surface tension modifier, those which are effective without adversely affecting the liquid medium and the recording agent to be used are selected from among conventionally known ones so as to appropriately satisfy desired properties. Used.

Specifically, examples of suitable viscosity modifiers include polyvinyl alcohol, hydroxypropyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, methyl cellulose, a water-soluble acrylic resin, polyvinyl pyrrolidone, and gum arabic.

Surface tension adjusters suitably selected and suitably used as desired include anionic, cationic and nonionic surfactants, specifically, polyethylene glycol ether sulfate as anionic, Ester salts, etc. Cationic polyoxy-2-vinylpyridine derivatives, poly-4-vinylpyridine derivatives, etc. Nonionic polyoxyethylene alkyl ethers, polyoxyethylene alkylphenyl ethers, polyoxyethylene alkyl esters, polyoxyethylene sorbitan monoalkyl Esters and polyoxyethylene alkylamines.

In addition to these surfactants, amine acids such as diethanolamine, propanolamine and morphophosphoric acid, basic substances such as ammonium hydroxide and sodium hydroxide, and substituted pyrrolidones such as N-methyl-2-pyrrolidone are also effectively used. Is done.

These surface tension modifiers do not adversely affect each other or other components, and impart to the recording medium in which the above physical property values are formulated, such that a recording liquid having a desired value of surface tension is formulated. If necessary, two or more kinds may be used as a mixture within the specified range.

The amount of the surface tension adjuster to be added is appropriately determined according to 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 0.001 to 0.01
It is desirable to use parts by weight.

The pH adjuster is used to adjust the chemical stability of the prepared recording liquid, for example, to a predetermined pH value in order to prevent changes in physical properties due to long-term storage, and to prevent sedimentation and aggregation of the recording agent and other components. Are added at appropriate times within a range not to deviate from the various characteristic values.

As the pH adjuster preferably used in the present invention,
As long as the desired pH value can be controlled without adversely affecting the recording liquid to be prepared, most of them can be mentioned.

Specific examples of such a pH adjuster include lower alkanolamines, for example, monovalent hydroxides such as alkali metal hydroxides, and ammonium hydroxide.

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

As the lubricant to be used, those which are more effective than those generally known in the technical field of the present invention, in particular, are thermally stable as long as the recording liquid to be prepared does not deviate from the physical properties described below. Are suitably used. Specific examples of such a lubricant include polyalkylene glycols such as polyethylene glycol and polypropylene glycol, alkylene glycols having an alkylene group containing 2 to 6 carbon atoms such as butylene glycol and hexylene 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-
Pyrrolidone oligomer; and the like.

These lubricants are added in necessary amounts as required so as to satisfy the desired properties of the recording medium, and the amount of the lubricant is usually 0.1 to 1 with respect to the total weight of the recording liquid.
It is desirably 0 wt%, preferably 0.1 to 8 wt%, and most preferably 0.2 to 7 wt%.

The above lubricants may be used alone or in combination of two or more under conditions that do not adversely affect each other.

The recording liquid used in the recording apparatus of the present invention is added with a necessary amount of the above-described additives as required. Further, when the recording liquid adheres to a recording member, the formability of the recording liquid film and the film strength are reduced. In order to obtain an excellent product, a resin polymer such as an alkyd resin, an acrylic resin, an acrylamide resin, polyvinyl alcohol, and polyvinylpyrrolidone may be added.

The recording medium used in the recording apparatus of the present invention uses specific heat, thermal expansion coefficient, thermal conductivity, viscosity, surface tension, pH, and charged recording droplets so as to have the above-described various recording characteristics. In the case of recording, it is desirable that the compounding is performed so that the characteristic value such as the specific resistance is within the condition range of the characteristic.

In other words, these properties have important relevance to the stability of spinning development, responsiveness and fidelity to the action of thermal energy, image density, chemical stability, fluidity in the fluid path, etc. Therefore, in the present invention, it is necessary to pay sufficient attention to these when preparing the recording liquid.

It is desirable that the above-mentioned various properties of the recording liquid that can be effectively used in the recording apparatus of the present invention have the values shown in Table 1 below. It is not necessary to satisfy the numerical conditions as shown in (1), and some of these physical properties may be different depending on the required recording characteristics.
It suffices to take values that satisfy the conditions in the table. However, specific heat, coefficient of thermal expansion, thermal conductivity, viscosity, and surface tension are desirably specified in Table 1. Of course, it goes without saying that the more the properties of the prepared recording liquid satisfying the values shown in Table 1, the better the recording is performed.

Thus, the invention described in JP-B-56-9429,
A liquid ink is supplied from an ink supply source and an ink liquid chamber having an ejection hole for ejecting the liquid ink is opened, and the liquid ink in the ink liquid chamber is heated to generate air bubbles in the ink liquid chamber, and the liquid ink is discharged. An ink jet recording apparatus including a heating element that causes a pressure rise, and a cooling device that cools the liquid ink in the ink liquid chamber and the heating element, wherein a Peltier effect element is used as the cooling device. In the conventionally known bubble jet technology including the technology described above, the inventor of the present invention has performed a large number of head manufacturing experiments while generating or applying external heat (such as a pulse laser or the like) to the thermal energy action section. It has been found that there is a relationship between the accumulation of heat and the ejection performance when an ink droplet is ejected from the orifice. That is, as the heat is accumulated in the head, the ink properties which greatly affect the generation of bubbles such as ink viscosity and surface tension and the ejection of ink droplets change every moment, and it has been found that the ejection performance is not constant. .

Object The present invention has been made in view of the above-mentioned circumstances, and in particular, in a large multi-array bubble jet recording head, aims at improving the ejection performance by effectively cooling the thermal energy acting portion. It was done.

Configuration In order to achieve the above-described object, the present invention provides a thermal energy operation unit that accommodates a recording medium to be introduced, generates bubbles in the recording liquid by heat, and generates an action force associated with an increase in the volume of the bubbles. A orifice for communicating with the flow path and discharging the recording liquid by droplets by the action force, and introducing the recording liquid into the flow path by connecting to the flow path. A liquid chamber for introducing the recording liquid into the liquid chamber, and in the case where the number of the thermal energy action section, the flow paths and the orifices is 64 to 256, A heat radiation plate is provided in direct contact with the heating element substrate or the lid substrate of the flow path. Hereinafter, a description will be given based on examples of the present invention.

In FIGS. 3 to 5, the principle of the bubble jet has been described using a head having four orifices.
If the number of orifices is relatively small as in this example,
Although it is effective to provide a cooling device as described in Japanese Patent Publication No. 56-9429 made by the present applicant, a certain discharge performance can be obtained even if it is not provided. This is because the number of orifices is small, that is, the number of heat energy generating portions (heating elements) is small, and the amount of generated heat is small, so that heat is released by natural heat radiation. However, as the number of orifices is increased in order to increase the printing speed, the balance between the amount of heat that escapes due to natural heat radiation and the total amount of heat generated and generated by the heating element is lost, and the head gradually accumulates heat. And the ejection performance changes accordingly. In view of this point, the inventor of the present invention has conducted a trial production experiment of a head having a different number of orifices, and as far as the number of orifices (in other words, the heat energy acting portion), even if there is no device for heat dissipation and cooling,
It was found experimentally whether the ejection performance could be maintained. Table 2 shows an example of the result.

In Table 2, the mark 吐出 indicates excellent discharge performance, the mark 良好 indicates good, and the mark △
The mark indicates good when the environmental temperature is low (20 ° C. or less), and the mark X indicates bad (unusable).

1 (a) and 1 (b) are configuration diagrams for explaining an embodiment of a recording head according to the present invention.
1 is a cover substrate, 2 is a heat generating substrate, 13 is a heat radiation cooling means (for example, a heat sink), 4 is an orifice, (a) shows an example in which the heat sink 13 is attached to the heat generating substrate 2 side, and (b) shows An example is shown in which a heat sink 13 is attached to the lid substrate 1 side. From Table 2 above, it can be seen that excellent discharge performance can be obtained in all cases if sufficient radiation cooling means is provided, but if the number of orifices is small, for example, 25
In the case of six or less, it can be seen that sufficiently good results can be obtained with only the heat sink without providing the fan.
Also, in the case of 32 or less, it can be seen that sufficiently good results can be obtained without any heat radiation cooling means. Table 2 is an example, but according to the experiment of the present inventor, it is a goodbye to determine whether or not a good discharge performance can be obtained by providing the heat radiation cooling means around the number of orifices of about 100. I understand. Therefore, according to the present invention, when the number of orifices is 100 or more, the cover substrate forming the flow path in the vicinity of the thermal energy action portion of the head (for example, in the method using a heating element, the heating element substrate). And the like are provided with a heat radiation cooling means such as heating. In FIG.
Although an example of a fin-shaped heat sink is shown, it is not necessary to stick to this shape, and when the number of orifices is as small as 100 to 200 or the like, a simple plate-shaped heat sink may be used. As is clear from Table 2, when the heat sink and the fan are combined, a remarkable effect is exhibited particularly when the number of orifices is large, and in the case of a multi-array system in which the orifice covers the entire paper width (the number of orifices is One head unit has a size of 2000 to 3000. This includes, for example, a case where a plurality of small head units having about 100 orifices are arranged to form a large multi-array head unit of 2000 to 3000. ), Especially effective.

Also, as in the invention described in Japanese Patent Publication No. 56-9429 made by the present applicant, a Peltier element or the like is used, and the Peltier element is used for cooling, and the heat is radiated by a heat sink or cooled by a heat sink plus a fan. You may.

Effects As is clear from the above description, according to the present invention, in the multi-array bubble jet, heat is not stored in the head, so that the physical properties of the ink are constant and the ejection performance is stable. )
Has a remarkable effect.

[Brief description of the drawings]

1 (a) and 1 (b) are configuration diagrams for explaining an embodiment of the present invention, respectively, and FIG. 2 is an operation explanation of a bubble jet head as an example of an ink jet head to which the present invention is applied. FIG. 3 is a perspective view showing an example of a bubble jet head, FIG. 4 is an exploded perspective view,
FIG. 5 is a view of the lid substrate viewed from the back side, FIG. 6 is a view for explaining the details of the bubble jet recording head, and FIG. 7 is a view for explaining the structure of the bubble generating means using the heating resistor. FIG. 8 is a block diagram for explaining an example of a heating element drive circuit, FIG. 9 is a diagram for explaining an example of bubble generating means using laser light, and FIG. FIG. 11 is a diagram for explaining an example of a printer, FIG. 11 is a diagram for explaining an example of a bubble generating means using discharge, and FIGS. 12 to 19 are discharge electrodes shown in FIG. 11, respectively. FIGS. 20 to 23 and FIGS. 24 to 27 are diagrams for explaining a control example in a case where recording is performed by incorporating a recording head into a recording apparatus. 1 ... lid substrate, 2 ... heating substrate, 4 ... orifice, 13
……heatsink.

Claims (1)

(57) [Claims] 1. A storage device for accommodating a recording liquid to be introduced,
A flow path provided with a thermal energy action section for generating air bubbles in the recording liquid by heat and generating an action force accompanying an increase in the volume of the bubbles; and An orifice for discharging droplets, a liquid chamber for communicating with the flow path and introducing the recording medium into the flow path, and a means for introducing the recording medium into the liquid chamber. In the case where the number of orifices, the flow path and the orifice of the thermal energy action section are 64 to 256
A liquid jet recording head comprising a heat radiating plate directly in contact with a heating element substrate of the liquid jet recording head or a lid substrate of the flow path.