JP2980128B2 - Liquid recording head - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a liquid jet recording head, and more particularly, to a recording head of an ink 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 method is disclosed in, for example, US Pat. No. 3,060,429 (Tele type method),
Recording liquid droplets are generated by electrostatic attraction, and the generated recording liquid droplets are subjected to electric field control according to a recording signal, and recording is performed by selectively adhering the recording liquid droplets onto a recording member. It is.

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 described, for example, in US Pat. No. 3,596,275,
The method disclosed in US Pat. No. 3,298,030 and the like (S
Weet method) in which droplets of the recording liquid with a controlled charge amount are generated by a continuous vibration generation method, and the generated droplets with a controlled charge amount are subjected to a uniform electric field. The recording is performed on the recording member by flying between the deflection electrodes.

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, and a continuous vibration generation method is used. This is a method in which small droplets are generated and atomized for 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 system is, for example, a system (Stemme system) disclosed in US Pat. No. 3,747,120, and this system is fundamentally different from the above three systems 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 liquid 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 problems such as the fact that it is difficult to use a multi-nozzle recording head, and 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 a piezoelectric vibrating element having a desired resonance number. However, since the recording liquid 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.

Further, Japanese Patent Application Laid-Open No. 48-9622 (the aforementioned U.S. Pat.
No. 120) describes, as a modification, the use of thermal energy instead of the mechanical vibration energy by means such as the piezo-vibration element.

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.

Moreover, according to the technical contents described in the above-mentioned publication, it is not possible to quickly form a preparation state for the next liquid discharge after performing the liquid discharge with 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.

The present applicant has proposed a so-called bubble jet inkjet system utilizing thermal energy as Japanese Patent Application Laid-Open No. 54-51837. This is an excellent method in which the energy acting portion on the ink can be reduced and high-density arrangement is possible.

Japanese Unexamined Patent Publication No. Sho 56-123869 has been proposed to embody this technique. This is a proposal for a method of forming an ink flow path using a photosensitive resin. Although there is a description of a method of manufacturing the ink flow path, there is no detailed description of actual ink discharge performance. Therefore, it is a matter of course that "to provide an ink jet recording head having a configuration in which the ink flow path is finely processed with high accuracy and high precision", but the idea of improving the disadvantages described later is Absent. That is, when photolithography is performed using a photosensitive resin (that is, exposure and development are performed) and a flow channel is formed, the degree of progress of development during development is determined when a plurality of patterns are arranged. Since the central portion and the end portion are different, the size of the central portion of the channel groove and the size of the end portion of the channel groove are not the same, and when this is used as a head, The ejection speed or mass of the ink droplets coming out of the central outlet and the ink outlets coming out of the edge outlets are different, in other words, the particleization characteristics of the central and end outlets are constant And there was no idea to improve the disadvantage of poor printing quality when printing.

On the other hand, in Japanese Patent Application Laid-Open No. 63-4955, the size of the electrothermal transducer of the bubble jet ink jet head varies due to etching. It is disclosed that both ends of the conversion element are treated as dummy heaters and are not actually used. However, JP 63
Japanese Patent No. 4955 merely shows the concept of providing dummy heaters on both sides of a heater actually used, and does not consider how much dummy heaters should be provided. Japanese Patent Application Laid-Open No. 63-4955 is an invention in which a dummy heater is provided, and there is no detailed description of a discharge port and a flow path of the present invention described later, and there is no idea how to deal with them.

On the other hand, JP-B-54-39134 is known. This is because, in a charge control type (continuous flow type) multi-inkjet head, in a plurality of continuously flying jets, local aerodynamic drag appears more prominently in an end jet. The invention, which was deemed to be of low image quality due to the time delay before the ink droplets reached the paper surface, provided that the non-marking fluid was used so that the jets at the edges would not receive local aerodynamic drag. Nozzles (dummy nozzles) for injecting nozzles. However, Japanese Patent Publication No. 54-39134 discloses a dummy nozzle for compensating for a delay in the speed of an ink flying droplet due to air resistance, but has a different purpose and a different configuration. Further, Japanese Patent Publication No. 54-39134 merely shows the concept of providing dummy nozzles, and does not specifically describe how many dummy nozzles should be provided.

Object The present invention has been made in view of the above-described circumstances, and specifically shows a range in which variation in ejection performance is allowable, and is to provide a specific proposal for manufacturing a high-yield head. Another object of the present invention is to provide a liquid jet recording head in which the sizes of the ejection ports and the flow paths are within a range in which the variation of the ejection performance is allowed to obtain high-quality printing. It is.

Configuration In order to achieve the above object, the present invention provides a discharge port for discharging a recording liquid to form flying droplets, a flow path for guiding the recording liquid to the discharge port, In a liquid jet recording head having an energy action section for applying energy, the discharge port and the flow path are:
A flow channel formed of a photosensitive resin is formed on a substrate provided with the energy acting portion, and thereafter a cover member is provided to form and arrange a plurality of channels, and among the plurality, a plurality of channels are actually recorded. What is used is a liquid ejecting recording head which is a discharge port and a flow path near the center except for several to several tens of the both ends, and in the arrangement direction of the discharge port and flow path area near the center. When the length is Lu, and the length in the arrangement direction of only one side of the area of the discharge port and the flow path that is not used for recording is Ld, Ld ≧ 0.0126Lu + 0.458 is satisfied, or the recording liquid is discharged. An ejection port for forming a flying droplet,
In a liquid jet recording head having a flow path for guiding the recording liquid to the discharge port, and an energy operation section for applying energy to the recording liquid, the discharge port and the flow path may include the energy operation section. A flow channel formed of a photosensitive resin is formed on the attached substrate, a plurality of the grooves are formed and arranged by providing a lid member, and the length of the arranged region in the arrangement direction is Lu, A pattern region formed of a photosensitive resin different from the ejection port and the flow path is provided on both sides of the arrangement area of the ejection port and the flow path, and the arrangement direction of the ejection port and the flow path on only one side of the pattern area. When the length is Ld, Ld ≧ 0.0126Lu + 0.458 is satisfied.

First, the principle of ink ejection by bubble jet will be described with reference to FIG. In the figure, 21 is a lid substrate, 22
Is a heating element substrate, 27 is a selection (independent) electrode, 28 is a common electrode,
29 is a heating element, 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 an equilibrium state on the orifice surface.

3B shows a state in which the heater 29 is heated until the surface temperature of the heater 29 sharply rises and boiling development occurs in the adjacent ink layer, and minute bubbles 31 are scattered.

(C) shows a state in which the adjacent ink layer, which is rapidly heated on the entire surface of the heater 29, is instantaneously vaporized to form a boiling film, and the bubbles 31 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 bubble has grown to the maximum, and the 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 applying the electric pulse.

(E) shows a state where the bubble 31 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 31 further contracts, the ink comes into contact with the heater surface, and the heater surface is cooled more rapidly. 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.

Next, a method of manufacturing a bubble jet head using the above principle will be described with reference to the manufacturing steps shown in FIGS. The embodiment shown here relates to a discharge port, a flow path, and a common liquid chamber made of a cured film of a photosensitive resin. In the figure, 1
Is a substrate, 2 is an ink ejection pressure generating element, 3 is a thin film, 4 is an adhesive layer, 5 is a dry film photoresist, 6 is a photomask, 7 is an adhesive, 8 is a flat plate, and 9 is a groove.

In the process shown in FIG. 4, a desired number of ink ejection pressure generating elements 2 such as heating elements and piezo elements are arranged on a substrate 1 made of glass, ceramic, plastic, or metal. Si for the purpose of imparting properties and electrical insulation
The thin film 3 of O ₂ , Ta ₂ O ₅ , glass, etc. is covered. Although not shown, a signal input electrode is connected to the ink ejection pressure generating element 2.

In the step shown in FIG.
The adhesive layer 4 is formed on the surface of the substrate 1 having a thickness of about 1 μm to 5 μm.

At this time, the desired liquid adhesive is prepared by a known method, for example,
After coating on the substrate surface by a spinner coating method, a dip coating method, or a roller coating method, it is semi-cured.

Specifically, in the case of the spinner coating method, the viscosity 2
Apply ~ 15 CP of adhesive at 1000-5000 rpm. In the case of the dip coating method, the substrate 1 is immersed in an adhesive having a viscosity of 20 to 30 CP and then pulled up at a constant speed of 20 to 50 cm / min.

Furthermore, in the case of the roller coating method, the viscosity is 100 to 300 CP.
Is applied at a roller speed of 60 to 200 cm / min.

The type of the adhesive used here is not particularly limited as long as a predetermined adhesive force is exhibited, but in the present invention, a photocurable resin adhesive is particularly recommended for convenience in production.

As described above, the photocurable resin adhesive suitable in the present invention includes, for example, an unsaturated polyester resin and a monomer, dimer or oligomer compound having at least one unsaturated double bond in a molecule (methylmethacrylate). Acrylate, styrene, diallyl phthalate, etc.) or one or more resins such as silicone, urethane, epoxy, etc. modified to have one or more unsaturated polyester and at least one unsaturated double bond in the terminal chain or main chain. It is composed of a combination of the above-mentioned monomers, dimers, oligomers and the like.
In the present invention, when these adhesives are formed of a compound based on a bonding agent Si, a silane coupling agent may be mixed with the adhesive or the substrate 1 may be used in advance.
It is also effective to treat the surface with a silane coupling agent.

In the subsequent step shown in FIG. 6, after cleaning and drying the surface of the adhesive layer 4 of the substrate 1 obtained through the step shown in FIG. Dry film photoresist 5 (thickness,
(About 25 μ to 100 μ) are laminated at a rate of 0.3 to 0.4 f / min under a pressure of 1 to ³ kg / cm ³ . At this time, the dry film photoresist 5 is fused to the adhesive layer 4. Thereafter, according to the properties of the used adhesive, the adhesive layer 4 is irradiated with ultraviolet rays to be fully cured. Thereafter, even when a considerable external pressure is applied to the dry film photoresist 5, the substrate 1
It does not peel off from Subsequently, as shown in FIG. 6, a photo master 6 having a predetermined pattern is superimposed on a dry film photoresist 5 provided on the substrate surface, and exposure is performed from above the photo master 6. At this time, it is necessary to align the installation position of the ink ejection pressure generating element 2 with the position of the pattern by a known means.

FIG. 7 is an explanatory view showing a process in which an unexposed portion of the exposed dry film photoresist 5 is dissolved and removed with a developing solution composed of a predetermined organic solvent.

Next, in order to improve the ink resistance of the exposed portion 5P of the dry film photoresist 5 left on the substrate 1, a heat curing treatment (for example, heating at 150 to 250 ° C. for 30 minutes to 6 hours) or ultraviolet irradiation is performed. (E.g., at an ultraviolet intensity of 50-200 mw / tm < ² > or higher) to sufficiently enhance the polymerization curing reaction.

It is also effective to use both the above-mentioned heat curing and curing by ultraviolet rays.

If the used adhesive layer 4 remains in the groove 9, it is eluted in the ink to change the quality of the ink, clog the ink passage, or impair the function of the ink discharge pressure generating element 2. Therefore, in the present invention, the adhesive layer 4 is simultaneously photo-cured during the pattern exposure of the dry film photoresist 5 (FIG. 6), and the uncured adhesive is developed in the subsequent development step using an organic solvent. The agent layer 4 is dissolved and removed together with the photoresist 5 (FIG. 7).

FIG. 8 shows a groove 9 serving as an ink passage formed by the dry film photoresist 5P cured after the above-described sufficient polymerization.
FIG. 4 is a view showing a state where a flat plate 8 is adhered or simply crimped to form a ceiling on the substrate 1 on which is formed.

In the step shown in FIG. 6, the concrete method for forming the ceiling is as follows: 1) A flat plate 8 made of glass, ceramics, metal, plastic or the like is spinner-coated with an epoxy-based adhesive to a thickness of 3 to 4 μm. Thereafter, the adhesive 7 is pre-heated to form a so-called B-stage, which is then bonded onto the cured photoresist film 5P to fully cure the adhesive. Or 2) On a photoresist film 5P obtained by curing a flat plate 8 of a thermoplastic resin such as an acrylic resin, an ABS resin, or polyethylene,
There is a method of directly performing heat fusion.

In the above process, when the adhesive layer 4 is an acrylic resin-based photocurable adhesive applied to a thickness of 1 μm, or when the adhesive layer 4 is an acrylic resin-based photocurable adhesive applied to a thickness of 2 μm. For each of the agents, the peel strength of the photoresist cured film 5P from the substrate 1 (test A) and the photoresist cured film 5P (1 mm × 1 mm) formed on the substrate 1 were immersed in water at 80 ° C. for one week. When the residual ratio (test B) on one surface of the substrate was measured, the results were as shown in Table 1.

Here, FIG. 9 is a schematic perspective view showing the appearance of the recording head after the process of FIG. 8 is completed. In the drawing, 9-1 is an ink supply chamber, 9-2 is an ink liquid flow path, and 10 is an ink supply chamber 9-1.
2 shows a through hole for connecting an ink supply pipe (not shown).

In the above-described embodiments, a dry film type, that is, a solid film is used as the photosensitive composition (photoresist) for forming a groove. However, the present invention is not limited to this. Photosensitive compositions can, of course, also be used.

Then, as a method for forming this photosensitive composition coating film on the substrate, in the case of a liquid, a method using a squeegee used when producing a relief image, that is, a wall having the same height as a desired photosensitive composition film thickness is formed. This is a method in which the excess composition is removed around a substrate by a squeegee. In this case, the viscosity of the photosensitive composition is suitably from 100 CP to 300 CP. Also, the height of the wall around the substrate needs to be determined in consideration of the reduction in evaporation of the solvent component of the photosensitive composition.

On the other hand, in the case of a solid, the photosensitive composition sheet is stuck on a substrate by heating and pressing.

It should be noted that it is more advantageous to use a fixed film type in terms of handling and in that the thickness can be easily and precisely controlled. Examples of such solid materials include those manufactured by DuPont, permanent photopolymer coating RISTON, solder masks 730S, 740S, and 750F.
R, 740FR, and SM1 are commercially available photosensitive resins. In addition, the photosensitive composition to be used includes many photosensitive compositions used in the field of ordinary photolithography, such as a photosensitive resin and a photoresist. Examples of these photosensitive compositions include, for example, diazoresin, P-diazoquinone, and further, for example, a photopolymerization type photopolymer using a vinyl monomer and a polymerization initiator, and a duplex type photopolymer using a sensitizer with polyvinyl cinnamate and the like. A mixture of orthonaphthoquinonediazide and a novolak-type phenolic resin, a mixture of polyvinyl alcohol and a diazo resin, a polyether-type photopolymer obtained by copolymerizing 4-glycidylethylene oxide with benzophenone or glycidylchalcone, N, N-dimethylmethacrylamide and For example, a copolymer with acrylamide benzophenone, an unsaturated polyester-based photosensitive resin (eg, APR (Asahi Kasei), Devista (Teijin), Sonne (Kansai Paint), etc.), an unsaturated urethane oligomer-based photosensitive resin, a bifunctional acrylic monomer A photosensitive composition in which a photopolymerization initiator and a polymer are mixed together, a dichromic acid-based photoresist, a non-chromium-based water-soluble photoresist, a polyvinyl silicate photoresist, a cyclized rubber-azide photoresist, and the like. No.

FIG. 10 shows an example for further improving the reliability and durability. This is obtained by adding one more step after the step of FIG. That is, the protective film 11 is formed in a portion where the photosensitive resin comes into contact with the ink. As such a protective film, any protective film may be used as long as it has excellent ink resistance. For example, the present inventors have formed a thin film such as SiO ₂ or Si ₃ N ₄ by a technique such as CVD or sputtering, and have obtained good results. Other suitable materials include SiC, Al ₂ O _{3 and the} like. Some organic materials are also suitable. For example, ethylene tetrafluoride is preferable because of its excellent ink resistance. The tenth
In the figure, a diagram is shown in which a protective film is also formed at the bottom of the flow channel, but this is basically not necessary (because there is no photosensitive resin). Further, it is desirable not to consider the heat conduction of the heat generating portion. This can be removed by photolithographic techniques.

In the head manufactured by the above-described method, when the photosensitive resin forming the flow path pattern is developed, the speed of development is increased when there are many patterns (for example, a plurality of patterns in the present invention). A central region where the discharge ports and flow paths are arranged) and a position where the pattern is only on one side (for example, in the present invention, both end portions where a plurality of discharge ports and flow paths are arranged) ) Are generally known to be different. This is because it is difficult to replenish the developing solution where there are many patterns in the central region, and it is easy to replenish the developing solution when the patterns at both ends are only on one side. Development speed is fast. Therefore, since the size of the flow path and the discharge port is different at the center portion and both end portions, the discharge speed or mass of the ink droplets discharged from them are different, in other words, the particleization characteristics are not constant, and the This is known as a phenomenon that printing quality is poor.

In view of the above, the present inventors apply an energy to the recording liquid, a discharge port for discharging the recording liquid to form flying droplets, a flow path for guiding the recording liquid to the discharge port. In a liquid jet recording head having an energy action part for the ejection ports and flow paths, a flow path groove formed of a photosensitive resin is formed on a substrate provided with the energy action part,
After that, a cover member is formed, and a plurality of ejection ports and flow paths are arranged. Of the plurality, the one actually used for recording is the center excluding several to several tens at both ends. The present invention proposes a liquid jet recording head that is a discharge port and a flow path in the vicinity. In such a head, in the relationship between the ejection ports and flow paths used for recording and the ejection ports and flow paths not used for recording, a certain number of ejection ports and flow paths that are not used or If the area is larger than a certain area, the above-described drawback of poor print quality can be solved. However, unnecessarily increasing the number of unused discharge ports and flow paths or the area where they are formed not only increases the size of the printer head, but also generally increases the size of the head formed using an expensive Si wafer or the like. Therefore, the cost is high and it is very uneconomical. Therefore, a discharge port and a flow path that do not use them must be provided to the minimum necessary. We have:
Experiments and trial production were repeated in an enormous amount, and the optimum conditions were quantitatively clarified to make it possible to produce a head for mass production that has good printing quality and is the most cost-effective. Hereinafter, the results of the study by the present inventors will be described. Hereinafter, a description will be given based on examples of the present invention.

FIG. 1 is a configuration diagram for explaining an embodiment of a liquid jet recording head according to the present invention. FIG. 1 is a conceptual plan view showing discharge ports, flow paths, and a common liquid chamber formed on a heating element substrate. FIG. Since this diagram is a conceptual diagram, the actual heating element, electrodes,
And the flat plate forming the ceiling is omitted. In the figure, an area A is a discharge port and a flow path used for printing, and the length in the arrangement direction is Lu. Area B is a discharge port and a flow path that are not used for printing, and the length in the arrangement direction is Ld. The B region is generally provided on both sides of the A region, and the lengths Ld in the arrangement direction are equal to each other. However, the lengths Ld are not necessarily equal and may not be equal in terms of the layout of the head. In that case, the shorter value is applied to the present invention as Ld. Since the definitions of Lu and Ld are measured from the center line of the flow path and the discharge port,
It is a channel unit for one ejection. Therefore, an error of several μm to several tens μm is included due to a difference in arrangement density or the like.

In the above Table 1 and FIG. 1, the pattern of the discharge ports and flow paths not used for printing and the pattern of the discharge ports and flow paths used for printing have the same shape. Considering the origin of the present invention to improve the above-mentioned disadvantages caused by non-uniform circulation, so-called dummy patterns of discharge ports and flow paths not used for printing are not necessarily used for printing. It is not necessary to use the same pattern as the pattern of the discharge port and the flow path. In short, it is used for the above-described recording so that the developing solution is supplied and circulated so that the developing speed of the area used for the recording becomes uniform. If an appropriate pattern is developed simultaneously as a dummy during pattern development in the area, the supply and circulation of the developing solution to the area used for recording are performed uniformly, and no problem is obtained. Rukoto will arrive it is easy to imagine. Second
The table shows the results of trial production and evaluation of the dummy area pattern in a grid pattern as shown in FIG. The definitions of Lu and Ld are
This is the same as in the case of Table 1 and FIG.

From the results of the above-mentioned trial production, evaluation and examination, the present inventors formed a flow channel groove by exposing and developing with a photosensitive resin on a substrate provided with an energy acting portion, and thereafter forming a channel member by providing a lid member. In the inkjet head, it has been found that in order to keep the variation in the ejection performance within an allowable range, it is sufficient to provide ejection ports and flow paths not used for recording, so-called dummy nozzles, or dummy patterns corresponding thereto. . However, a dummy nozzle or a dummy pattern corresponding thereto has no effect if its area is too small, and the cost is increased only if it is provided indefinitely. Based on the above results, the present inventors assume that the length in the arrangement direction of the ejection ports and flow paths used for recording is Lu, and that the ejection ports and flow paths not used for recording are arranged on only one side of the so-called dummy nozzle area. If the ejection ports and the flow paths or the dummy nozzles and the corresponding dummy patterns are laid out so as to fill the length of the direction or the flow path of the corresponding dummy pattern, the completed ink jet head will be able to eject ink droplets. It has been found that variations in speed are small, and therefore, printing with high image quality can be obtained.

That is, by designing the head so as to satisfy Ld ≧ 0.0126Lu + 0.458, it is possible to obtain a head suitable for mass production of high quality with little variation. In addition, it is added that this empirical formula is suitably applied when the area of the ejection port and the flow path used for recording is an area of 3.3 to 43.3 mm and the arrangement density thereof is 200 to 800 dpi. Although the description has been made with a bubble jet using a heating element, the present invention is also applicable to a method using laser or discharge energy.

FIG. 11 is a view for explaining another means for generating bubbles in the recording liquid, in which 81 is a laser oscillator, 82 is a light modulation drive circuit, 83 is a light modulator, 84 is a scanner, 85 Is a condenser lens, and the laser light generated by the laser oscillator 81 is pulse-modulated by the optical modulator 82 in accordance with an image information signal which is input to the optical modulator driving circuit 82, electrically processed and output. . The pulse-modulated laser light passes through a scanner 84 and is condensed by a condenser lens 85 so as to be focused on the outer wall of the thermal energy action section. To generate air bubbles. Alternatively, the wall 86 of the thermal energy action section is made of a material that is permeable to laser light, and the condensing lens 85 is used to store the recording liquid inside.
The light may be focused so as to be focused on 87, and bubbles may be generated by directly heating the recording liquid.

FIG. 12 is a diagram for explaining an example of a printer using a laser beam as described above. The nozzle portion 91 is provided with a high density (for example, 12 nozzles / mm or more) and a paper width of the paper 91 (for example, A4 An example is shown in which the components are integrated so as to cover the entire width.

The laser light emitted from the laser oscillator 81 is applied to an optical modulator.
Guided to 83 entrance openings. In the optical modulator 83, the laser light is subjected to strong and weak modulation in accordance with an image information input signal to the optical modulator 83. The optical path of the modulated laser light is bent by the reflecting mirror 88 in the direction of the beam expander 89, and enters the beam expander 89. The beam diameter is expanded by the beam expander 89 while keeping the parallel light.
Next, the laser beam having the expanded beam diameter is incident on a rotating polygon mirror 90 that rotates at a high speed and a constant speed. The laser light swept by the rotating polygon mirror 90 is imaged by the condenser lens 85 on the outer wall 86 of the thermal energy action section of the drop generator or on the recording liquid inside. As a result, air bubbles are generated in each of the thermal energy action sections, and a suitable amount of the recording liquid is discharged to perform recording on the recording paper 92.

FIG. 13 is a view showing still another bubble generating means. In this example, a pair of discharge electrodes 100 arranged on the inner wall side of the thermal energy action section receives a high voltage pulse from the discharge device 101, A discharge is generated in the recording liquid, and bubbles are instantaneously formed by heat generated by the discharge.

FIGS. 14 to 21 are diagrams showing specific examples of the discharge electrode shown in FIG. 13, respectively.The example shown in FIG. Discharge (at low energy).

In the example shown in FIG. 15, 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. 16, 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. 17 is a ring-shaped electrode, and is basically the same as the example shown in FIG. 16, and is a modified embodiment thereof.

In the example shown in FIG. 18, 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. 19, one ring-shaped electrode is formed on the wall surface of the thermal energy action section. This aims at facilitating manufacturing in which electrodes are formed two-dimensionally on the substrate, in addition to the effects 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. 20, the ring-shaped electrode forming portion of the example shown in FIG. 19 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. 18 by adding a three-dimensional guide.

The example shown in FIG. 21 is different from the example shown in FIG. 20 in that the ring-shaped electrode forming portion has a structure in which the ring-shaped electrode formation portion is dropped from the periphery, and again, the generated bubbles are formed stably. Is done.

Effects As is apparent from the above description, according to the present invention, by providing ejection ports and flow paths that are not used for recording, so-called dummy nozzles, and further optimizing the conditions for providing the same, the most efficient production can be achieved. High-performance heads with little variation can be mass-produced. Also, by using the head, printing of very high image quality can be performed (corresponding to claim 1).

The pattern of the dummy area does not necessarily have to have the same shape as the discharge port and the flow path, and therefore, the photomask can be simplified and the cost can be reduced. Production efficiency effect by providing a dummy area under certain conditions (experimental formula of the present invention), or the fact that high-performance heads can be mass-produced and high-quality printing can be performed using them. Is the same as the operation and effect corresponding to claim 1 (corresponding to claim 2).

[Brief description of the drawings]

FIG. 1 is a configuration diagram for explaining one embodiment of a liquid jet recording head according to the present invention, and shows a discharge port, a flow path, and a common liquid chamber formed on a heating element substrate. FIG. 3 is a view showing another embodiment in which the dummy region of the flow path is formed in a lattice shape, and FIG.
FIG. 4 to FIG. 8 are diagrams for explaining a process of manufacturing a recording head using the principle shown in FIG. 3, and FIG. The figure is a perspective view of the recording head after the production is completed.
FIG. 11 is a diagram illustrating a protective film provided after the process of FIG. 7, FIG. 11 is a diagram illustrating an example of a bubble generating unit using laser light, and FIG. 12 is a diagram illustrating an example of a printer. Figure,
FIG. 13 is a view for explaining an example of a bubble generating means using discharge, and FIGS. 14 to 21 are views each showing a specific example of the discharge electrode shown in FIG. 1 ... substrate, 2 ... ink ejection pressure generating element, 3 ... thin film, 4 ...
… Adhesive layer, 5… dry film photoresist, 6 ……
Photomask, 7 ... adhesive, 8 ... flat plate, 9 ... groove, 9-1
... Ink supply chamber, 9-2 ... Ink liquid flow path.

 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tomoaki Nakano 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd. (56) References JP-A-62-191156 (JP, A) JP-A Sho 63-4954 (JP, A) JP-A-62-90254 (JP, A)

Claims (2)

(57) [Claims] An ejection port for ejecting a recording liquid to form flying droplets, a flow path for guiding the recording liquid to the ejection port, and an energy action for applying energy to the recording liquid. In the liquid jet recording head having a portion, the discharge port and the flow path are formed by forming a flow path groove formed of a photosensitive resin on a substrate provided with the energy action section, and thereafter providing a lid member. A plurality of formed and arranged, and among the plurality, the one actually used for recording is a liquid ejection recording head which is a discharge port and a flow path near the center excluding several to several tens at both ends. Lu, the length in the arrangement direction of the region of the discharge port and the flow path near the center is Lu,
A liquid jet recording head characterized by satisfying Ld ≧ 0.0126Lu + 0.458, where Ld is the length in the arrangement direction of only one side of the area of the discharge port and the flow path not used for recording. 2. An ejection port for ejecting a recording liquid to form flying droplets, a flow path for guiding the recording liquid to the ejection port, and an energy action for applying energy to the recording liquid. In the liquid jet recording head having a portion, the discharge port and the flow path are formed by forming a flow path groove formed of a photosensitive resin on a substrate provided with the energy action section, and thereafter providing a lid member. Are formed and arranged in a plurality, and the length of the arranged area in the arrangement direction is
Lu, a pattern area formed of a photosensitive resin different from the discharge port and the flow path is provided on both sides of the arrangement area of the discharge port and the flow path, and the discharge port and the flow path on only one side of the pattern area. Ld ≧ 0.01, where Ld is the length in the array direction of
A liquid jet recording head satisfying 26Lu + 0.458.