JPH02206558A - Liquid jet recording device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a liquid jet recording device, and more particularly to a recording device for an inkjet printer.

[11] 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,
However, 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 disclosed in, for example, US Pat. No. 3,060,429 (Teletype method).
The generation of small droplets of recording liquid is carried out by electrostatic attraction,
The generated recording liquid droplet is controlled by an electric field according to the recording signal,
Recording is performed by selectively depositing recording liquid droplets onto a recording member.

To explain this in more detail, 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 is converted into a recording signal. Accordingly, the droplet is caused to fly between x and y deflection electrodes configured to be electrically controllable, and the droplet is selectively deposited on the recording member by changing the intensity of the electric field to perform recording.

The second method is the method (Sweet method) disclosed in, for example, U.S. Pat. No. 3,596,275, U.S. Pat. Recording is performed on a recording member by generating droplets with a controlled amount of charge and flying the generated droplets between deflection electrodes to which a negative electric field is applied.

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. Pat. No. 3,416,153 (Hertz method),
In this method, an electric field is applied between a nozzle and a ring-shaped charged electrode, and small droplets of recording liquid are generated and atomized using a continuous vibration generation method to perform recording. That is, in this method, the atomization state of droplets is controlled by modulating the electric field intensity applied between the nozzle and the charging electrode in accordance with the recording signal, and the gradation of the recorded image is produced.

The fourth method is, for example, the method disclosed in US Pat. No. 3,747,120 (Stsmme 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, recording is performed by

This Stama+s method performs recording by ejecting small droplets of recording liquid from an ejection port in response to a recording signal.

In other words, the Steam method applies an electrical recording signal to a piezo vibrating element attached to a recording head that has an ejection port for ejecting 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 according to the mechanical vibrations and adhering them to the recording member.

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 requires a high voltage to generate droplets, and it is difficult to use a multi-nozzle recording head, making it unsuitable for high-speed recording.

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 of being able to record images with excellent gradation by atomizing recording liquid droplets, but on the other hand, it is difficult to control the atomization state and fog occurs in the recorded image. In addition, it is difficult to create a multi-nozzle recording head.
There are various problems such as being unsuitable for high-speed recording.

The fourth method has relatively many advantages compared to the first to third methods. In other words, the configuration is simple, and in order to perform recording by ejecting recording liquid from the ejection opening of the nozzle on-demand (on-do and), a small ejecting liquid is used as in the first to third methods. Inside the drops.

There is no need to collect droplets that are not needed for image recording, and there is no need to use a conductive recording liquid as in the first and second methods, so there is material freedom for the recording liquid. It has great advantages such as high strength. On the other hand, it is difficult to make the recording head multi-nozzle because there are problems in processing the recording head, and it is extremely difficult to miniaturize the piezoelectric vibrating element having the desired resonance number. Since the recording liquid droplets are ejected into flight using the mechanical energy of the mechanical vibration of the piezo vibrating element, it has the disadvantage that 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) discloses, as a modification,
It is described that thermal energy is used instead of using mechanical vibration energy by means such as the piezo vibration element described above.

That is, the above-mentioned publication describes a so-called bubble jet liquid jet recording device that uses a heating coil that directly heats liquid as a pressure increasing means instead of a piezo vibrating element to generate steam that causes a pressure increase. There is.

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 no suggestion whatsoever.In addition, the heating coil is located at the deepest part of the bag-shaped liquid chamber, far from the liquid ink supply path, so the head structure is complicated. In addition, for continuous repeated use at high speeds,
It is not suitable.

Moreover, based on the technical content described in the above-mentioned publication, it is not possible to immediately prepare for the next liquid ejection after ejecting the liquid using the generated heat, which is important for practical use.

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.

In particular, bubble jets are so-called drop ondem
It is extremely effectively applied to the AND recording method, and not only can ejection orifices be provided at a high density, but also heat generating parts can be provided at the same density as the ejection orifices, making it easy to realize high-density multi-orifice formation. However, there are still problems to be solved in actual production. In the case of multi-orifice, JP-A-58-1852
As shown in Publication No. 68, there is a serial number on the head side.
A method is known in which a parallel conversion element is provided to reduce the number of signal lines input to the head section. This method is a well-known technique that is also used in thermal recording heads.
Bubble jet heads require extremely precise processing such as formation of heat generating parts, electrode parts, and flow path formation, and furthermore, the provision of control elements such as serial/parallel conversion elements causes a decrease in yield. In addition, when driving with serial/parallel exchange, time is required to send the drive information to the serial/parallel conversion element, and in ultra-highly integrated heads such as full-line types, this time will change the ejection frequency. For example, 4 KHz
When discharging at a higher level, an extremely high processing speed is required, and the processing elements become expensive. This problem was solved in Japanese Patent Application Laid-Open No. 58-63457, and as described in this publication, the liquid discharge part and the immediate action control part are divided and both are electrically connected by wire bonding. This connection solves the above drawbacks.

However, when creating a higher density and multiple orifices, a new problem arises. Namely, as shown in the above publication, when forming 132 orifices at a density of 8 orifices/ymta, , the length of the orifice row is 1
For example, if the interval between adjacent bonding butts is 200 μm, the length of the bonding butt row will be 17.6851 mm, so it is not much different from the orifice row length and the electrodes can be arranged approximately parallel. Therefore, variations in the voltage applied to each heating resistor due to differences in electrode resistance do not significantly affect the speed, shape, size, etc. of the ejected droplets. 5
0pm is 50μ, which is a sufficient margin compared to the electrode spacing of 125μm to 200μm, so if the above-mentioned minute difference in electrode resistance is not allowed, as shown in Japanese Patent Laid-Open No. 60-204370, adjacent electrode It is also possible to eliminate the difference in electrode resistance by making a detour within the range of . However, when trying to create a full-line type orifice with an ultra-high density of 16 or more, for example, A4
The number of orifices is 3,360 in a full-line type, and when bonding pads are provided at a pitch of 200 μm for an orifice row length of 210 mm, the length is 671.8 m, which is more than three times the length of the discharge orifice. , and the heating resistor substrate itself becomes expensive. Furthermore, the mating board to be connected must of course be longer than the same length, and the mating board (control element board or wiring board) also becomes expensive.

Furthermore, in the case of an ultra-high-density multi-orifice head, each layer of the heating resistor, electrode, protective layer, etc. on the heating resistor substrate is
Optimally, it is formed by photolithography, and as the heating resistor substrate becomes larger, a larger photomask must be used, which also has the drawback of increasing costs.

Furthermore, because the difference between the orifice row length and the bonding butt row length is large, the difference between the shortest electrode and the longest electrode becomes significant.For example, if the orifice row is placed in the center of the substrate as shown in Figure 4, When the width of the substrate is 10a++m, the difference in length between the electrode 201 located at the center and the electrode 202 at the end is approximately 452m+a, and the difference in electrode resistance due to this difference cannot be ignored. It is. When orifices are formed at an ultra-high density, such problems cannot be ignored when the number of orifices exceeds 256, and especially when the number of orifices exceeds 512, the dispersion of the ejection speed becomes large and the print quality deteriorates significantly. This problem becomes more and more noticeable as the electrode becomes thinner as the density increases.

Furthermore, as mentioned above, the length of the heating resistor board and the length of the mating board are more than three times the length of the discharge orifice, that is, the printing area, so the machine body is larger than the printing area. This also caused the problem that the cover for the main body of the machine became expensive. The higher the density of these defects, the more
Although the problem becomes more serious as the integration becomes higher, there is no mention of it in the above-mentioned publications. The present inventors have manufactured a large number of heads,
Experiments have shown that the above-mentioned drawback, which was hardly a problem with a head with a density of 8/Oboro and 132, is an extremely serious problem with an ultra-high density multi-orifice head. It was discovered that this is largely related to the arrangement spacing of the electrode terminals, leading to the present invention.

m-sheet The present invention was made in view of the above-mentioned circumstances, and
The main objective is to provide an ultra-high density multi-orifice head with stable ejection speed and high print quality. Also,
Another objective is to provide an inexpensive ultra-high density multi-orifice inkjet printer. Another object is to provide an ultra-high density multi-orifice head capable of ejecting at high frequencies. The present invention is particularly effective for heads with high-density orifices of 16 orifices/m+a or more, and is particularly effective for heads with high density orifices of 256 or more orifices/m+a.
The purpose of this invention is to provide a liquid jet recording device configured to be most effective in high frequency ejection above Hz.

In order to achieve the above object, the present invention includes a plurality of heat generating resistors provided on a substrate and electrically connected to at least one pair of electrodes, and a plurality of heat generating resistors corresponding to each of the heat generating resistors. a liquid passage communicating with the discharge orifice and having at least a part thereof provided with a thermal energy application section that applies thermal energy to the recording liquid discharged from the discharge orifice; In a liquid jet recording device having electrode terminals that are connected to each other, and in which the heating resistors are provided at an extremely high density, an arrangement interval r of the heating resistors and an arrangement interval R of the electrode terminals are set.

It is characterized by satisfying the relationship r≦R≦2.5r. Hereinafter, the present invention will be explained based on examples.

First, the principle of ink ejection using a bubble jet will be explained based on FIG. In the figure, 21 is a lid substrate, 2
2 is a heating resistor substrate, 27 is a selective (independent) electrode, 28 is a common electrode, 29 is a heating resistor, 30 is ink, 31 is a bubble, and 32 is a flying ink droplet.

(a) is a steady state, in which the surface tension of the ink 30 and the 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.

(,) shows a state in which the adjacent ink layer that is rapidly heated on the entire surface of the heater 29 instantaneously vaporizes to form 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.

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

In (f), the air bubbles 31 are further contracted, the ink comes into contact with the heater surface, and the heater surface is 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 drops 5 to 1 droplets toward the recording paper.
It is flying at a speed of 0 m/sec.

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).

Figure 5 is a top view of 1 heat generating part, 301.30
2 and 303 are heating resistors, 304, 305, and 306 are selection electrodes of each heating resistor, and 307 is a common electrode. 6th
The figure is a structural diagram of the heat generating part. Heat storage layer 4 on substrate 401
02, heating resistor M403, selective electrode layer 404, common electrode layer 405, heating part/antibody protection layer 406, electrode protection layer 4
07 using semiconductor process technology such as photolithography. The substrate material is silicon,
Ceramics, glass, etc. are used. A film of Sin is formed as a heat storage layer on the substrate. The heat storage layer is a heating resistor O
When N, heat escapes to the board and the heating resistor is turned off.
Sometimes contradictory properties are required to conduct heat appropriately to the substrate. For this reason, since the thickness of the heat storage layer greatly influences the generation and disappearance of bubbles, an appropriate thickness must be selected.1 Usually, a thickness of 0.1 to 10 μm is preferable.

In addition, as a method of forming the heat storage 71, sputtering, sputtering, C
Existing thin film forming methods such as VD method and plasma CVD method can be suitably used.

Next, a heating resistor layer is provided on the heat storage layer. Examples of materials constituting the heating resistor layer include tantalum nitride, nichrome, silver-palladium alloy, silicon semiconductor, metallic glass, tin oxide, and further hafnium, lanthanum, zirconium, and titanium.

Examples include metals such as tantalum, tungsten, molybdenum, niobium, chromium, and vanadium, alloys thereof, and borides thereof. Among other things.

Metal borides are excellent as heating resistors. The best among them are hafnium boride, followed by zirconium boride, lanthanum boride, tantalum boride, and vanadium boride. Since the waveform is a so-called unrounded waveform, that is, it must immediately follow the input drive signal, it is not possible to make the resistance high, and it is also disadvantageous to make it too small rather than reducing power consumption. Therefore, usually 1
The thickness of the zero-heating resistor layer having a resistance of 0 to 500 ohms is generally 200 to 3 μm, preferably 1000 to 1 μm, taking into consideration the above resistance value and durability.

The heating resistor is formed by a photolithography technique and a thin film forming method such as a sputtering method, a CVD method, or a vacuum evaporation method. Therefore, the heat generating resistor can be formed extremely finely and precisely, and a heat generating resistor array with extremely high density and high integration can be formed.

FIG. 1 is a configuration diagram for explaining an embodiment of a liquid jet recording apparatus according to the present invention, and shows a heat generating resistor made by the method described above.

In FIG. 1, 501 is a heating resistor provided on a heat storage layer 502, and 503 is an end face on the orifice side.

504 is an end surface on the electrode terminal side. In FIG. 1, the length Q2 from the end face of the orifice to the end face on the electrode terminal side is shortened for explanation purposes, but in the case of ultra-high density such as 16 resistors/11 resistors, the interval Q1 between the heating resistors is 0. 0625a+Otori, and the inside of the heating resistor is smaller than 0.0625mm. Therefore, Ω2 is different from the length shown in FIG. 11, but actually becomes approximately 5+s+m or more due to the provision of a flow path, a common liquid chamber, etc., which will be described later.

However, if the distance between the orifice end face and the electrode terminal side end face is too long, the board cost will naturally increase, so it is usually
It is desirable to use it in a range above the cline and below 100 m11.

Electrodes and electrode terminal portions are patterned on this substrate using a photolithography technique and a thin film forming method such as a sputtering method, a CVD method, or a plasma CVD method. FIG. 2 shows a photomask for forming electrodes and electrode terminals. This photomask is patterned with a common electrode section 601, selection electrode sections 602 to 605, and electrode terminal sections 606 to 609. Moreover, the electrode terminal interval Q3 is Q1
It is patterned so that ≦Q3≦2.5 Ql.

As the constituent material of the electrode layer, many commonly used electrode materials can be used, for example.

AQ, Ag, Au, Pt, Cu, etc., and alloys of these metals are used. In addition, the thickness of the electrode layer is usually 500 ~
In an ultra-high density (16 lines/mm) bubble jet, preferably 2 μm, the pitch of the heating resistors is 62.5 μm, and the selection electrodes 304, 305,
The electrode width of 306 is determined by insulation with adjacent electrodes, electromagnetic losstalk that occurs between adjacent electrodes which is a particular problem due to high frequency driving, and because it is normally driven with a current of 10 mA to 500 mA, this driving current 15 μm to 50 μm, preferably 10 μm to 3
It is preferable to set it to 0 μm.

Examples of methods for arranging the electrode terminal portions include those shown in FIG. 8, and the present invention is suitably applied to all of them. FIG. 8(a) shows an example in which the electrode terminal portions 806 of the electrodes 804 are arranged in a row, FIG.
) is an example of arranging in three stages. Among these examples, when the width Qw of the electrode terminal portion is made the same, the number of arrays per unit length is the smallest in FIG. 8(a) and the largest in FIG. 8(c), and furthermore, The number of stages may be increased, but in that case, contact between bonding wires is likely to occur, so
It is preferable to keep it within the tier. The present invention has an effect on all arrangement methods including those described above, that is, regardless of the arrangement method, it has the effect as long as the relationship between adjacent electrode terminals satisfies the relational expression of the present invention.

After forming the electrodes, a protective layer is provided to cover at least the heating resistor. The characteristics required of the protective layer are to effectively transfer the heat generated by the heating resistor to the recording liquid, to protect the heating resistor from the recording liquid, and to protect the heating resistor from damage when bubbles disappear. It is to protect. Examples of materials constituting the protective layer include silicon oxide, silicon nitride, magnesium oxide, aluminum oxide, tantalum oxide, zirconium oxide, hafnium oxide, lanthanum oxide, yttrium oxide, manganese oxide, calcium oxide, aluminum nitride, boron nitride, Oxides such as tantalum nitride, nitrides, and composites thereof, as well as semiconductor thin films such as amorphous silicon and amorphous selenium can be used. Using these materials, vapor deposition method, sputtering method,
CVD method.

The protective layer is formed by a film forming method such as a plasma CVD method, a gas phase reaction method, or a liquid coating method. After that, an electrode protection layer 407 is formed. The properties required of the electrode protective layer include excellent liquid resistance and heat resistance, and good electrical insulation. Therefore, it is required to have good film-forming properties, have few pinholes, and not swell or dissolve in the ink used. As the material constituting the electrode protective layer, many materials that meet the above conditions can be used. For example, silicone resin,
Resins include fluororesins, aromatic polyamides, addition polymerized polyimides, metal chelate polymers, titanate esters, epoxy resins, phthalic acid resins, thermosetting phenolic resins, P-vinylphenol resins, Zylock resins, and triazine resins. .

Furthermore, various organic compound monomers such as thiourea,
Thioacetamide, vinylferrocene, 1.3.5-trichlorobenzene, chlorobenzene, styrene, ferrocene, pyrroline, naphthalene, pentamethylbenzene,
Nitrotoluene, acrylonitrile, diphenylselenide, P-toluidine, P-xylene, N,N-dimethyl-P-toluidine, toluene, aniline, diphenylmercury, hexamethylbenzene, malononitrile, tetracyanoethylene, thiophene, benzeneselenol, The film can also be formed by plasma polymerization using tetrafluoroethylene, ethylene, N-nitrosodiphenylamine, acetylene, 1.2.4-trichlorobenzene, propane, or the like.

However, if a high-density multi-orifice type recording head is to be manufactured, it is desirable to use, in addition to the above-mentioned organic materials, an organic material that can be extremely easily processed by fine photolithography as the material for forming the electrode protective layer.

Using a coating means such as a spinner or a roll coater, a photosensitive resin containing a resin having cavitation erosion resistance according to the present invention, such as photosensitive polyamide varnish or photosensitive polyimide varnish, is laminated. The thickness of the photosensitive resin layer is not particularly limited, but in consideration of practicality as an inkjet recording head, it is preferable to have a relatively thick layer of at least about 2 to 100 μm. Therefore, it is preferable that the photosensitive resin be one that can be laminated to such a thickness. Commercially available photosensitive resins include the aforementioned photosensitive polyamide varnishes, such as Printite EF95, Toρ1on, and Nylon. Print (Nylon
print), or photosensitive polyimide varnishes such as Photonice VR-3140 and Selectilux VTR-2 are preferably used.

The substrate on which the photosensitive resin is laminated in this manner is subjected to treatments such as exposure or development as described below to form ink channels made of the photosensitive resin.

In addition, the photosensitive resin is Photonease VR-31 as shown below.
40 will be described as an example, but it goes without saying that the method of forming the ink flow path wall may be any method depending on the type of photosensitive resin used, etc.

In other words, photosensitive resin Photoneese VR-3140
The conditions for the prebeta are not particularly limited, but in this example, the conditions were 80° C. for 80 minutes.

After the preliminary beta is completed, a photomask having a desired pattern is placed on the Photoneese VR-3140, and then exposure is performed through this photomask.

After the exposure, the unexposed part of Photonice VR-3140 is treated with developer DV-505 for Photonice VR-3140.
Grooves that are to be used as ink flow channels are formed by developing the film using a etchant and dissolving and removing the unexposed portions.

After dissolving and removing the unexposed areas in this manner, a post bake is performed to harden the exposed areas of Photoneese VR-3140 remaining on the substrate, and Photoneese VR-3140 is also applied to the ink channel walls having the desired pattern on the substrate. Forms a cured film. Post-bake conditions are not particularly limited, but in this example, 100°C, 30 minutes → 300°C, 30 minutes
The test was carried out in three steps: 0 minute → 400°C for 30 minutes.

A flat plate serving as a cover for the ink flow path is laminated on the substrate on which the ink flow path wall made of the cured film of photosensitive resin is formed in this manner.

The head portion of the bubble jet formed as described above is shown in FIG. 7, with a head 701 and a wiring board 705.
are adhered or fitted onto the AQ support plate 702, and the two are electrically connected by wire bonding with an aluminum wire or the like 703. The diameter of the aluminum wire requires ultra-high density wiring, and the size of the electrode terminal is limited (width approximately 120μ).
It is preferable to use a material with a diameter of 15 μm to 100 μm, and in this example, 1% S with a diameter of 25 μm is used.
i, AQ line was used. Furthermore, after wire bonding, the wires are sealed with a sealant to protect them from contact with the wires and damage to the wires.

The present inventors fabricated a head of 512 heating resistors at a density of 16 pieces/l1lI on a silicon substrate using the structure and manufacturing method described above. At this time, the intervals between the electrode terminals were set to 65 μm, 80 μm, 135 μm, and 160 μm, and the stability of the ejection speed was compared. Also, 24 bottles/l
A head of 512 heating resistors was made with a density of l11,
45μm, 60μm, 80μm, 100μm, 135μm
A comparative experiment was conducted with a terminal spacing of m. The results are shown in Table 1.

The degree of variation in Table 1 is 2% or less for O, 2 to 5% for 0, and 5% or more for x.

At this time, the length Ll of the heating resistor row and the length L2 of the terminal row
By taking the ratio (L□/L) and the required substrate length L, the results are as shown in Table 2 below.

From Table 2 and above, the length Ll of the heating resistor row and the length of the terminal row,
It was found that when the ratio (L/L2) was 0.4 or more, a head with good ejection stability, that is, high print quality, could be obtained. In other words, when the relationship between the pitch R between terminals of adjacent electrodes and the pitch r between adjacent heating resistors is R≦2.5r, high printing quality can be obtained. Here, making the pitch R between the electrode terminals smaller than the pitch r between the heating resistors will reduce the bonding accuracy, and the minimum board length of 2 heating resistor rows is required, and the terminal row length should be less than that. However, since this is only a technical difficulty, sufficient effects can be obtained by satisfying the relationship r≦R≦2.5r.

In the present invention, the inkjet head and the wiring board are electrically connected by wire bonding, but the connection method is not limited to this.
Semiconductor element mounting techniques such as (mated bonding) can also be suitably used. In addition, the objects to be electrically connected to the inkjet head include boards such as glass and engineered poxy boards, FPCs, patterned ceramic boards, etc.
Alternatively, it may be a metal terminal provided on a support plate, or a so-called relay board or relay cable in which a control element or the like is mounted.

As is clear from the above description, according to the present invention, the arrangement pitch r of the heating resistors and the pitch R of the electrode terminals are set such that r≦R≦
By setting 2.5r, it is possible to realize an ultra-high density multi-orifice head with high printing quality.Furthermore, by satisfying the above relationship, the size of the substrate is not required more than necessary, and the substrate cost and photomask cost can be reduced. We were able to realize an inexpensive ultra-high density multi-orifice head. Furthermore,
It is now possible to provide heating resistors in one-to-one correspondence with drive wires, without serial/parallel conversion.
We were able to realize an ultra-high-density multi-orifice hectome that enables high-speed discharge.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram for explaining one embodiment of a liquid jet recording device according to the present invention, showing a heating resistor, and FIG. 2 is a diagram showing a photo mask for forming electrodes and electrode terminals. FIG. 3 is a principle diagram for explaining ink ejection and bubble generation/disappearance from the head. FIG. 4 is a diagram showing orifice rows and bonding pad rows. top view. FIG. 6 is a configuration diagram of a heat generating section, FIG. 7 is a perspective view of a bubble jet head, and FIGS. 8(a) to (c) are arrangement configuration diagrams of electrode terminals. 501... Heat generating resistor, 502... Heat storage layer, 503
... Orifice side end surface, 504 ... Electrode terminal side end surface. 601... Common electrode section, 602-605... Selection electrode section, 606-609... Electrode terminal section. Patent applicant Ricoh Co., Ltd. Figure 1 Figure 2 Figure 4 Figure 5 Figure 6 (a) Figure 8 (b) (C)

Claims (1)

[Claims] 1. A plurality of heat generating resistors provided on the substrate and electrically connected to at least one pair of electrodes, a discharge orifice provided corresponding to each of the heat generating resistors, and communicating with the discharge orifice; The heating resistor has a liquid path in which at least a part thereof is provided with a thermal energy acting portion that applies thermal energy to the recording liquid discharged from the discharge orifice, and an electrode terminal electrically connected to the electrode. In a liquid jet recording device in which bodies are arranged in an ultra-high density, the arrangement interval r of the heating resistors and the arrangement interval R of the electrode terminals are r.
A liquid jet recording device characterized in that the relationship satisfies the relationship: ≦R≦2.5r.