JP2905374B2 - Inkjet head - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording head of a so-called ink jet recording apparatus for recording by ejecting ink, and more particularly to a color ink jet head.

[0002]

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

In such an ink jet recording method, recording is performed by causing droplets of a recording liquid, called so-called ink, to fly and adhere to a recording member. It was previously proposed in Japanese Patent Publication No. 56-9429. Here, in summary, the ink is heated by heating the ink in the liquid chamber to generate air bubbles, causing a pressure rise in the ink, and ejecting the ink from a fine capillary nozzle for recording. Since then, many inventions have been made using this principle.

[0004]

SUMMARY OF THE INVENTION As one of them,
For example, a multicolor liquid ejecting apparatus disclosed in Japanese Patent Publication No. 63-3750 is known. In this example, the apparatus ejects three colors of inks A, B, and C. The ink ejection ports and the flow paths are arranged in a line in the order of A, B, C, A, B, C,. It is arranged in. Therefore, since the ink flowing in each of the adjacent flow paths is all different, the same number of holes as the ink discharge ports are formed in the block serving as the liquid supply unit for supplying the ink. A corresponding hole is also formed in the road, and ink is supplied from the hole. Although the size of this hole is not described in the publication, it is necessary to make the size of the hole approximately the same as that of the ink flow path, and the formation thereof is considerably troublesome. In addition, the technique of assembling the head by aligning all of the holes has considerable accuracy and causes an increase in cost.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a simple ink jet head capable of performing color printing. Another object of the present invention is to realize high quality image quality by such a simple ink jet head. Still another object of the present invention is to make such a simple inkjet head compact and further reduce the running cost. Others of the present invention
The purpose of the inkjet is to integrate the color ink container
Higher orifice as well as a more compact head
The purpose is to obtain position accuracy. Still another object of the present invention
Is a running color printer to which the present invention is applied.
The aim is to reduce costs. Yet another Eye of the Invention
Specifically, a color ink container integrated type ink to which the present invention is applied.
In addition to reducing the cost of ink jet heads,
It is to obtain the orifice position accuracy.

[0006]

According to the present invention, in order to solve the above-mentioned problems, (1) an ink container for supplying a recording liquid is formed integrally with a recording head portion, and an ink container in the liquid chamber of the recording head portion is formed. It has a thermal energy generating means for applying thermal energy to the recording liquid. The thermal energy causes bubbles to be generated in the thermal energy acting portion in the recording liquid, and the bubbles are ejected by the acting force accompanying the volume increase of the bubbles. In an ink container-integrated ink jet head that performs recording by causing the recording liquid to fly as droplets from an orifice and attaching the recording liquid to a recording surface, the ink jet head uses a plurality of colors of recording liquid.
A plurality of colors are applied to the recording head together with the recording head to be ejected.
Together with the ink container that supplies the recording liquid
Ink for inkjet devices mounted on, scanned and recorded on
A jet head, wherein the thermal energy action section comprises:
A plurality of heating elements are formed in groups for each color on one common substrate, and a flow path substrate corresponding to the heating elements and a flow path and a liquid chamber are formed. The orifices corresponding to each color are arranged in a straight line on the same plane. (2) In (1), the ink container is detachable from the recording head unit. (3) In the above (1) or (2), the ink container is detachable from the recording head unit for each color, and (4) the above (1) or (2) or ( In 3), the flow path substrate has flow paths for a plurality of colors;
The liquid chamber is a flow path substrate formed by integral molding of plastic. (5) In the above (1) to (4), the discharge orifices have a common orifice row corresponding to each color . The plate-shaped plastic region is perforated in a straight line with an excimer laser.

[0007]

A plurality of energy action portions for each color of the plurality of inks and fine ejection ports corresponding to the action portions are provided, and ejection port rows for each color form a row for each color independently of each other. In addition, the discharge ports are arranged so that the center line of those rows becomes one common center line, and thus has a simple configuration, and
Realize high-quality image quality.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, the operation of an ink jet head as an example of an ink jet head to which the present invention is applied will be described with reference to FIGS. 1 (a) to 1 (g). FIG. 1 (a)
1 (g), 1 is ink, 2 is meniscus,
3 is a heating element, 4 is a micro bubble, 5 is a bubble, 6 is an ink column,
Numeral 8 denotes a flying ink droplet, and the present invention is applied to such a valve jet type liquid jet recording head.

FIG. 1A shows a steady state in which the surface tension of the ink 1 and the external pressure are in an equilibrium state at the orifice surface, and the meniscus 2 is substantially coincident with the orifice surface. 6B shows a state in which the heater 3 is heated, the surface temperature of the heater 3 rises sharply, and the adjacent ink layer is heated until boiling development occurs, and minute bubbles 4 are scattered. (C) is a state in which the adjacent ink layer, which is rapidly heated on the entire surface of the heater 3, is instantaneously vaporized to form a boiling film, and the bubbles 5 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 6 starts growing from the orifice. (D) is a state in which the bubble 5 has grown to the maximum, and ink corresponding to the volume of the bubble is pushed out from the orifice surface. At this time, the heater 3 is in a state where no current is flowing, and the surface temperature of the heater 3 is decreasing. The maximum value of the volume of the bubble 5 is slightly shifted from the timing of applying the electric pulse. (E) shows a state where the bubble 5 is cooled by ink or the like and starts to contract.
At the leading end of the ink column 6, the ink flows backward from the orifice surface into the nozzle due to a decrease in the internal pressure of the nozzle due to the contraction of the bubble, and a neck 7 occurs in the ink column 6. (F) is a state in which the bubbles 5 are further contracted, the ink is in contact with the heater surface, and the heater surface is more rapidly cooled. At the orifice surface, the external pressure becomes higher than the internal pressure of the nozzle, so that the meniscus 2 largely enters the nozzle. The leading end of the ink column becomes an ink droplet 8 in the direction of the recording paper by 5 to 10
Fly at a speed of m / sec. In (g), bubbles are completely eliminated in the process in which the ink is supplied again (refilled) by the orifice by capillary action and returns to the state of (a).

FIG. 2 is a view showing a typical example for explaining a main part configuration of the liquid jet recording head as described above.
2A is a detailed front view of the bubble jet recording head viewed from the orifice side, and FIG.
FIG. 4 is a partial cross-sectional view taken along a line B. The recording head 10 shown in FIG. 2 has an electrothermal transducer 11 on its surface.
By joining a grooved plate 13 provided with a predetermined number of grooves having a predetermined linear density and a predetermined width and depth on the substrate 12 provided with the substrate 12 so as to cover the substrate 12, the liquid flies. has an orifice 14 (14 _1, 14 _2, 14 ₃₎ of the liquid discharge portion 15 including the formed structure for. The liquid discharge unit 15 includes a thermal action unit 16 in which thermal energy generated from the orifice 14 and the electrothermal converter 11 acts on the liquid to generate bubbles, and causes a rapid state change due to expansion and contraction of the volume. And

The heat acting portion 16 is located above the heat generating portion 17 of the electrothermal converter 11, and has a low heat acting surface 18 as a surface of the heat generating portion 17 which is in contact with the liquid. The heat generating section 17 includes a lower layer 19 provided on the substrate 12, a heating resistor layer 20 provided on the lower layer 19, and an upper layer 21 provided on the heating resistor layer 20. The heating resistor layer 20 (20 _1, 20 _2, 20 _3), the electrodes 22 and 23 for energizing the said layer 20 to generate heat is provided on the surface thereof, heat generated between the electrodes The heat generating portion 17 is formed by the resistance layer 20. Electrode 22
Is an electrode common to the heat generating section of each liquid discharge section, and the electrode 2
Reference numeral 3 denotes a selection electrode for selecting a heat generating part of each liquid discharge part to generate heat, and is provided along a liquid flow path of the liquid discharge part.

The upper layer 21 in the heat generating portion 17
In order to chemically and physically protect the heating resistance layer 20 from the liquid used, the heating resistance layer 20 is isolated from the liquid filling the liquid flow path of the liquid discharge unit 15 and the electrodes 22 and 23 are passed through the liquid. It has a function of preventing a short circuit between the electrodes and a function of preventing an electric leak between adjacent electrodes. The upper layer 21 has the function as described above. However, when the heating resistance layer 20 is liquid-resistant and there is no need to electrically short-circuit the electrodes 22 and 23 through the liquid, It is not always necessary to provide the heating resistance layer 2
It may be designed as an electrothermal converter having a structure in which the liquid immediately contacts the surface of the zero.

The lower layer 19 has a heat capacity control function.
In other words, the lower layer 19 is configured such that the heat generated in the heat generating resistance layer 20 is discharged to the substrate 12 when discharging the droplet,
The rate of conduction to the heat acting part 18 side is as large as possible,
After the droplet is discharged, that is, after the passage to the heating resistance layer 20 is turned off, the heat in the heat acting portion 18 and the heat generating portion 17 is quickly released to the substrate 12 side, and the liquid in the heat acting portion 16 is discharged. And for the generated bubbles to be rapidly cooled.

Examples of useful materials for forming the heating resistance layer 20 include a tantalum-SiO ₂ mixture,
Examples include tantalum nitride, nichrome, silver-palladium alloy, silicon semiconductor, and boride of metal such as hafnium, lanthanum, zirconium, titanium, tantalum, tungsten, molybdenum, niobium, chromium, and vanadium. Among these materials constituting the heat generating resistance layer 20, metal borides can be mentioned as being particularly excellent. Among them, hafnium boride has the most excellent properties, and then zirconium boride, Lanthanum boride, tantalum boride, vanadium boride, niobium boride are in that order.

The heating resistance layer 20 is made of the above-mentioned material,
It can be formed using a technique such as electron beam evaporation or sputtering. The film thickness of the heat generating resistance layer 20 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 heat generation per unit time is as specified. In general, the thickness is 0.001 to 5 μm, preferably 0.01 to 1 μm.

Materials for forming the electrodes 22 and 23 include:
Many commonly used electrode materials are effectively used, and specifically, for example, Al, Ag, Au, P
t, Cu, etc. are used, and these are provided at predetermined positions in a predetermined size, shape, and thickness by a technique such as vapor deposition.

The properties required for the protective layer (upper layer) 21 are such that the heat generated in the heat generating resistive layer 20 is not effectively transmitted to the recording liquid and the heat resistive layer 2
0 is protected. Useful materials for the protective layer 21 include, for example, silicon oxide,
Silicon nitride, hardened magnesium, aluminum oxide,
Examples include tantalum oxide and zirconium oxide. These can be formed using a technique such as electron beam evaporation or sputtering. The thickness of the protective layer 21 is usually 0.01 to 10 μm, preferably 0.1 to 5 μm, and most preferably 0.1 to 3 μm.

FIGS. 3 to 10 are schematic views for explaining the procedure for manufacturing the ink jet head applied to the present invention. In the step shown in FIG. 3, the substrate (heating element substrate) provided with the electrothermal transducer described in FIG. 2 is shown in a simplified manner, and the first substrate 30 made of a material such as silicon, glass, or ceramics is used. A predetermined number of ink discharge pressure generating elements 31 (heating elements in this case), which are energy action sections, are arranged, and if necessary, SiO ₂ , Ta ₂ O _{5 for} the purpose of imparting ink resistance and electrical insulation. , Glass and other thin film layers 3
2 is coated. Note that a signal input electrode (not shown) is connected to the ink ejection pressure generating element 31.

In the step shown in FIG. 4, after the surface of the thin film layer 32 is cleaned and dried,
A dry film type photoresist layer 33 which is a photosensitive resin layer (film thickness: about 10 μm to 100 μm)
Is heated to about 80 to 105 ° C., and
Lamination is performed under a pressure of 4 kg / cm ² at a speed of 4 f / min. At this time, the photoresist layer 33 is fused to the thin film layer 32. Subsequently, a photomask 34 having a predetermined pattern is overlaid on the photoresist layer 33, and exposure is performed from above the photomask 34. At this time, the position of the ink discharge pressure generating element 31 and the pattern of the photomask 34 are aligned by a known method.

FIG. 5 shows the exposed photoresist layer 33.
FIG. 4 is an explanatory view showing a step of dissolving and removing an unexposed portion with a predetermined developer. By this step, only the exposed portion of the photoresist layer 33 remains, and the unexposed portion is dissolved and removed. A common liquid chamber region (not shown) communicating with the ink flow channel is formed. Next, in order to improve the ink resistance of the remaining portion of the photoresist layer 33, a thermosetting treatment (for example, 1
Heating is performed at 50 to 250 ° C. for 30 minutes to 6 hours) or ultraviolet irradiation (for example, ultraviolet intensity of 50 to 200 mW / cm ² or more) to sufficiently promote the polymerization and curing reaction.
In addition, it is also effective to perform both the above-mentioned heat curing treatment and the curing treatment by ultraviolet rays.

In the above, an example is shown in which the ink flow channel 35 and the common liquid chamber region are formed in the dry film type photoresist layer 33. For example, the ink flow channel 35 has a height of more than 16 lines / mm. When fabricating a high-density, high-definition ink jet recording head arranged at a high density, it is desirable to form the ink flow channel by photolithography technology for a liquid photoresist. When a liquid photoresist is used, the coating method may be spin coating, roll coating, dip coating, screen spraying, printing, or the like. In addition, the viscosity is 500 to 2000 cp depending on the coating thickness.

FIG. 6 shows a plate-like member 4 which is a second substrate constituting a cover for the ink flow channel and the common liquid chamber region.
0 shows a process of laminating a dry film photoresist layer 41, which is a dry film type photosensitive resin layer, on one surface of the substrate. Note that the flat member 40
Is formed of glass, ceramic, or the like.

FIG. 7 shows a process in which the first substrate 30 and the flat member 40 are laminated, and the opposing photoresist layer 33 and dry film photoresist layer 41 are joined. The bonding is performed by heating the laminated first substrate 30 and the flat plate member 40 to 100 to 120 ° C. on a hot plate and applying a pressure of 0.03 kg / cm ² for 2 seconds. After the joining is completed, the dry film photoresist layer 41 laminated on the flat member 40 is irradiated with ultraviolet rays (for example, ultraviolet intensity of 50 to 200 mW / cm ² or more) in a non-oxygen atmosphere to dry the photoresist. It is also effective to sufficiently cure the film photoresist layer 41 or to perform a thermal curing treatment (for example, at 130 to 250 ° C. for 30 minutes to 6 hours).

FIG. 8 shows the appearance of the ink jet recording head after the step shown in FIG. 7 is completed.
The ink flow path 36 is formed by covering the ink flow path groove with the flat member 40, and the common liquid chamber 37 is formed by covering the common liquid chamber area with the flat member 40.

After the lamination of the first substrate 30 and the plate-like member 40 and the joining of the photoresist layer 33 and the dry-form photoresist layer 41 are completed as shown above, FIGS. In this way, the cutting is performed along the line aa orthogonal to the ink flow path 36, and the ink discharge port 36 a is formed on the cut surface and at the tip of the ink flow path 36 as shown in FIG. The reason for performing such cutting is to optimize the interval between the ink discharge pressure generating element 31 and the ink discharge port 36a in the ink flow path 36, and the region to be cut is appropriately determined. This cutting is performed by a dicing method usually employed in the semiconductor industry, and the dicing method is performed under the following conditions. As the dicing saw, DAD-2H / 5 (trade name, manufactured by Disco Corporation) was used, and as the blade, NBC-Z600 (trade name, 52 mm × thickness 0.27 mm × inner diameter 40 mm) manufactured by Disco Corporation was used.
Rotate at 000 rpm, send at a speed of 0.5 mm / s, and use pure water filtered through a 0.2 μm filter as cooling water.

FIG. 9 is a cross-sectional view taken along the line AA in FIG. 8. Next, the cut surface along the line aa is polished and smoothed, and the ink formed on the plate-shaped member 40 is formed. By attaching the ink supply pipe 43 to the inflow port 42,
The ink jet recording head shown in FIG. 10 is completed.

FIGS. 11 to 17 show examples of ink passages to discharge ports of another configuration for forming an ink jet head applied to the present invention. FIG. 11 is a perspective view of a recording head.
FIG. 12 shows a flow path substrate (FIG.
FIG. 12A is an exploded perspective view of a heating element substrate (FIG. 12B).
FIG. 13 is a perspective view of the flow path substrate (FIG. 12 (a)) as viewed from the back surface, in which 51 is a flow path substrate, 52 is a heating element substrate, 53
Is an ink inlet, 54 is a discharge port, 55 is a flow channel, 56 is a recess for forming a common liquid chamber, 57 is an individual lead electrode, 58 is a common lead electrode, 59 is a heating element, and a heating element substrate 52 The heating element 59 has lead electrodes 57 and 5
8 is formed. Since the method of manufacturing the heating element substrate 52 has already been performed in the above-described example, the description is omitted here. The flow path substrate 51 is manufactured, for example, by integral molding of a resin.

Examples of the resin material used include polysulfone, polyethersulfone, and the like having excellent ink resistance.
Polyphenylene oxide, polypropylene and the like are used. Among them, melt f which has good fluidity for molding
It is preferable to use a material having a low rate of 10 g / 10 minutes or more. As the molding machine, a commercially available injection molding machine is used.
A molding machine having a capacity of kg / cm ² or more is desirable. The cylinder temperature is 400 ° C to increase the fluidity of the resin.
Heat above. The mold is provided with the flow path substrate 51 shown in FIG.
Use a mold having a shape that is paired with the above. Further, a heater heat medium or the like is provided in the mold so that the material can be heated to a temperature equal to or higher than the thermal deformation temperature of the material of the mold in order to improve transferability. It is also effective to reduce the pressure of the resin-filled portion of the mold by using a vacuum pump or the like to enhance the transferability.

FIG. 14 is an exploded perspective view of a recording head applied to the present invention. As shown, the heating element substrate 52 and the flow path substrate 51 are laminated on a head holding substrate 61 in the order shown. Further, these laminates are pressed and assembled by a pressing spring 65 having an M-shaped cross section as a pressing member. In FIG. 14, reference numeral 63 denotes an adhesive for fixing the heating element substrate 52 to the head holding substrate 61, and an epoxy-based adhesive is preferably used. These substrates stacked in the order described above are heated from the upper side of the flow path substrate 51 by a pressing spring 65 having an M-shaped cross section.
A force in a direction substantially perpendicular to the plane 2 is applied. The presser spring 65 can be formed using, for example, phosphorus copper or a stainless steel plate for a spring. And
The claw 66 provided at the lower part of both ends is fitted into the hole 62 provided in the head holding substrate 61, and by engaging the two, mechanical pressure is applied from above the flow path substrate 51 to the plane of the heating element substrate 52. It is applied in a direction substantially perpendicular to the direction. As a result, a sufficient close contact between the heating element substrate 52 and the flow path substrate 51 is obtained. In addition, in this presser spring 65,
67 is a hole, and the ink introduction port 53 of the flow path substrate 51,
It receives insertion of a supply pipe that connects to an ink supply port on the supply tank (not shown).

In the present invention, the heating element substrate 52 and the flow path substrate 5
1 can obtain a sufficiently close contact state, but if necessary, an adhesive may be interposed between the two in order to enhance the sealing property of the ink. As the adhesive used at that time,
Very little elution to ink, for example, XB
An epoxy adhesive 3052 (made by Ciba-Geigy) can be used. Suitable curing conditions for the adhesive are obtained by leaving it in an atmosphere at 80 ° C. for 8 hours.

In the above description, the flow path substrate 51 has a structure in which the end of the flow path groove 55 forms the discharge port 54 as it is after the recording head is completed. However, in order to further stabilize the ink ejection, A configuration in which a discharge port is additionally provided at the end of the flow channel 55 may be employed. FIGS. 15 and 16 show examples of the configuration of such a flow path substrate.

15 and 16, the flow path substrate 70
Are the common liquid chamber forming recesses 71, the ink flow path forming grooves 72a, 72b,... Communicating therewith, and the ink discharge ports (orifices) 74a, 74b, Are provided in a desired number (two in the figure for simplicity), and the orifice plate 73 is provided.
Are provided integrally. In the configuration example of FIG. 15, the flow path substrate 70 is made of a resin such as polysulfone, polyethersulfone, polyphenylene oxide, or polypropylene having excellent ink resistance, and is integrally formed in the mold together with the orifice plate 73. It has been molded. On the other hand, in the configuration example of FIG. 16, the orifice plate portion 73 is made of the same resin material as the main body member of the flow path substrate 70, or made of another kind of resin material, and furthermore, is made of a metal material film This is manufactured separately from the main body of the flow path substrate 70, and inserted into a mold to perform insert molding.

Next, a method of forming the ink flow grooves 72a and 72b and the orifices 74a and 74b will be described. With respect to the ink flow channel groove, a resin is molded by a mold in which a fine groove having a pattern opposite to that of the ink flow channel is formed by a method such as cutting. Regarding the orifices 74a and 74b, a piece having the shape of the orifices 74a and 74b, for example, a cylindrical slide piece is arranged in the orifice molding portion in all the molds, and is filled with resin. Thereby, it can be formed in a mold.

As another method, the mold is formed without the orifices 74a and 74b in the mold, and is taken out of the mold from the end face side of the orifice plate portion 73 at the position where the orifice is to be formed. For example, the orifices 74a and 74b can be formed by irradiating ultraviolet rays with a laser device to remove and evaporate the resin. The ink channel grooves 72a and 72b and the concave portion for forming the common liquid chamber can also be formed by irradiating ultraviolet rays from a laser device. At this time, if an excimer laser is used appropriately, precise processing along the mask pattern can be easily performed.

In the embodiment, the ink channel groove width is 30 to 50 μm and the non-groove width is 20 to
Flow path substrate 7 having 40 μm orifice hole diameter of 20 to 40 μm
0 was obtained. Then, as shown in FIG. 17, a heating element substrate 7 having a heating element 75 and the like is provided for such a flow path substrate 70.
6 is brought into contact with the orifice plate portion 73 and joined to obtain a recording head main body.

As another example of forming the flow path substrate, for example, a highly accurate flow path or liquid chamber is formed by etching a photosensitive glass sold under the trademark of Photo Serum by Corning. A flow path substrate as shown in FIG. 13 can be obtained. As another example, only the flow path portion of the flow path substrate can be obtained by forming a large number of parallel grooves on a glass, ceramic, or the like using a dicing saw. Regardless of the method used to manufacture the head, when the head is formed by pressing the flow path substrate as described with reference to FIGS. 15 to 17 against the heating element substrate, as shown in FIG. Construct the head. Alternatively, after the pressing, both the components such as the adhesive are joined.

FIG. 18 is a view showing an example of an ink jet head according to the present invention. In the present invention, as shown in FIG.
A plurality of ink ejection elements 81Y, 81M and 81C of a plurality of colors are formed on a common heating element substrate section 80.
In this example, yellow (Y),
An example of three colors of magenta (M) and cyan (C) is shown. In this example and the following examples, the ink ejection elements and ejection ports for each color will be described as four for each color for simplification of the drawing, but in practice, 64 to 512 for each color are preferably used. Is done.

FIG. 19 is a view in which an ink tank section 82 for supplying Y, M, and C inks is provided in the recording head section of FIG. This drawing is a diagram showing the concept of the ink jet recording head of the present invention composed of a recording head portion and an ink tank portion, and is different from an actual one (to be described later).

FIG. 20 is a view showing the configuration of a so-called serial printer which carries out recording by mounting the ink jet head according to the present invention on a carriage. In FIG. 20, reference numeral 90 denotes an ink jet head according to the present invention; Represents a carriage, 93 represents a guide rod of the carriage, 94 represents a screw rod for moving the carriage, 95 represents a recording paper transport roller, and 96 represents a recording paper holding roller. ), A recording head 90 (in the illustrated example, the head shown in FIG. 19 is mounted) arranged in one line with Y, M, and C while reciprocating in the X direction in front of the recording paper 93. Make a record. In the present invention, each time the carriage is scanned once, the recording paper is moved in the arrow Y direction in the figure. Therefore, the area recorded by one scan is only the length of the ejection element of the head, that is, the length of the row of ejection ports. Further, since Y, M, and C are arranged in a line in the vertical direction, Y, M, and C are obtained by performing two or more scans.
The full color recording can be performed only when the printing areas of the C ink overlap.

FIG. 21 is a diagram for explaining the operation when the ink jet head according to the present invention is used.
FIG. 1 (a) shows only the ejection section of the ejection port of the ink jet head shown in FIG. 19 when viewed from the front.
FIGS. 18 and 19 show an ink jet head according to the present invention.
Since the heating elements for ejecting the inks of a plurality of colors are manufactured on a single common substrate as shown in (1), the center lines of the ejection port arrays of the respective colors coincide with each other. That is, ejection port arrays y ₁ , m ₁ , and c ₁ for ejecting inks of respective colors of Y, M, and C.
Are arranged in a row regardless of the color. As another example of such an ink jet that ejects inks of a plurality of colors, for example, a head as shown in FIG. 11 is manufactured independently for each color of Y, M, and C, and these are laminated. There is an ink jet, but an ink jet element for jetting each color of Y, M, and C is formed on one common substrate as in the present invention as compared with the ink jet (FIG. 18).
Is very advantageous without the complexity of the prior art in that independent heads of three colors must be stacked with high precision.

FIG. 18 shows an example in which the ink channels for each color are independently manufactured. If the channels for these three colors are integrally manufactured by molding plastic, the assembly cost is reduced. It can be significantly reduced. Alternatively, the same effect can be obtained by using photolithography as shown in FIGS. In other words, since the heating element substrate is a single common substrate, the flow path pattern formed thereon is the same in both cases of a single color and a plurality of colors. Because
It is much more advantageous to manufacture the ink channels of three colors on one common substrate than to separately manufacture the heads of three colors and perform a layered assembly.

FIG. 21B shows pixels (dots) on the paper when printing is performed on the entire surface while scanning with a carriage as shown in FIG. 20 using the above-described ink jet head.
In the figure, a circle with a horizontal line indicates a dot of Y, a circle with a diagonal line on the upper right indicates a dot of M, and a circle with a diagonal line on the lower right indicates a dot of C. (If Stated differently, the recording linear transport direction) discharge port arrangement direction of the dot-dot-center distance P ₁ of, consistent with the nozzle array density, dot center distance P ₂ of the carriage scanning direction, the above ejection ejecting the ink at a timing such that the same dot center distance P ₁ in the outlet arrangement direction. That is, the density of the recorded dots is the same as the ejection port array density in both the horizontal and vertical directions. In general, when given by specific numbers,
For example, printing is performed at 400 dpi, in which case P
₂ is 63.5 μm.

Here, the distance between the Y, M, and C discharge port arrays, in other words, the distance between the centers of the adjacent Y and M discharge ports, or the distance between the centers of the M and C discharge ports. Is P ₁ ×
When a natural number is taken (FIG. 21 (a) is a natural number of 3
), Continue with the above imprinting,
When the dots of Y, M, and C overlap each other,
All three colors M and C form dots at the same location to create a mixed color. In this case, since three colors are overlapped in one place for realization, there is a problem that image quality is deteriorated due to color bleeding, or drying time after recording is slow. Therefore, in the present invention, in order to improve this point, the following is performed.

FIG. 21C is a view for explaining an example in which the arrangement of the discharge ports shown in FIG. 21A is improved.
This shows an ink ejection port array as in FIG. 21 (a). In the example shown in FIG. 21C, of the Y, M, and C ejection port arrays, only the M ejection port row is slightly shifted in the Y ejection port row direction. This shift amount s
Is, for example, P / 2 × a natural number.
It is not limited to this amount. For example, the term of P / 2 may be P / 3. This amount is appropriately determined in consideration of the physical properties of the ink used, the amount of spread of dots on the paper surface, and the like. By shifting the ejection port array in this way, when printing as described above is performed, for example,
The Y color dots and the M color dots are not completely overlapped with each other, but are shifted with a shift amount of the ejection port array to form a mixed color. Therefore, it is possible to prevent a decrease in image quality due to ink bleeding.

Next, still another feature of the present invention will be described. In the above example, among the ejection port arrays of Y, M, and C, the ejection port array is shifted only by M, but Y and C are completely overlapped when the above-described printing is performed. Will be copied. Therefore, here, since the center distance of the discharge ports adjacent to each other (the end of Y and the end of C), which is not shifted, is P × natural number, they are completely overlapped and printed. In order to avoid printing, printing is performed by shifting the timing at which ink is ejected during carriage scanning. The amount of shifting the timing is set to P / 2 or less.

The effect obtained by the embodiment of the present invention will be described with reference to FIG. 22 showing three color dots to be formed. FIG. 22A shows dots Y (a circle with a horizontal line), M (a circle with a diagonal line on the upper right), and C (a circle with a diagonal line on the right) printed in the same place. This is a rare case where color mixing occurs. On the other hand, in FIG. 22B, the color mixture is obtained by shifting the ejection port array as described above or changing the timing of ink ejection so that Y, M, and C do not completely overlap the same location. Is the case. In the figure, y is the shift of the center-to-center distance between the Y dot and the M dot obtained by shifting the M ejection port array, and x is the Y and C dot that has not been subjected to the ejection port array shift. This is a shift obtained by changing the ejection timing in the carriage scanning direction.

In the above description, an example of three colors of Y, M, and C has been described. However, the present invention is also applicable to an ink jet having an array of four orifices in which black (B) is added. Is done. An example is shown in FIG. 23. In this case, as shown, the ink ejection element 81B for black is further added to the example of FIG. FIG. 24 (a)
This shows one of the ejection port arrays of the head of the present invention to which B is added, and the ejection port arrays of M and B are slightly shifted in the direction of the ejection port arrays of Y and C, that is, by y. It is an example. By shifting the timing of the ejection port array and the timing of the ink ejection in the carriage scanning direction as described above, the dots of each color are slightly shifted as in the case of the three colors of Y, M, and C, that is, x minutes. The four colors can be mixed by shifting them so that they do not completely match. In this case, a group of Y and M ejection port arrays and C
In the groups of ejection port arrays B and B, the timing at which ink is ejected during carriage scanning is changed. FIG. 24B shows an example of four-color dots obtained by changing the timing of the ejection port array shift and ejection. Black (B) is indicated by white squares.

In the above description, the discharge port of the present invention has a square shape.
It may be a triangle. In addition, although the ejection port array of each color is separated between the colors, as described with reference to FIG.
× A natural number of 1 may be adopted as a natural number so that there is no gap between the colors (FIG.
FIG.

According to the present invention, as described above, the ink discharge elements of each color are arranged on one common heating element substrate in one row (= the center line of the discharge port row of each color coincides). Next, an example will be described in which the head having such a configuration is compact, easy to handle, and has a low running cost. FIG.
9 shows the concept of such a head configuration.
This is more specifically shown in FIG.

FIG. 25 shows a plurality of colors (in this example, Y, M,
(A) is an overall perspective view, (b) is an exploded perspective view, and 100 is a head unit. , 101 is a head chip, 102 is a print circuit, 103 is an upper cover, 104 is an ink container, 105
(105Y, 105M, 105C) is a teleless mesh filter, 106 (106Y, 106M, 106C)
Is a foam material containing ink, and 107 is a bottom cover. In this example, a head portion and an ink container portion connected to the head portion are internally divided into three parts, and Y, M, and C inks are separately filled. . As described above, since the head unit in which a plurality of colors are integrated can be formed very compact, when mounted on the carriage, it is lightweight and small, so that only a small carriage is required, and the motor for driving the carriage is also small. Energy saving can be realized.

FIGS. 26A and 26B are views for explaining an example in which only the ink container portion is configured to be separable in the multi-color ink container integrated type head unit shown in FIG. 25. FIG. An overall perspective view of the unit 110,
(B) shows a case where the head unit 110 is connected to the recording head unit 111.
FIG. 3 is a perspective view showing a state where the ink container unit 112 and the ink container unit 112 are separated.
As a result, even if a large amount of ink is consumed for color image printing, only the ink container unit 112 needs to be replaced, so that cost reduction is realized. Moreover, the advantages of the integrated color head described with reference to FIG. 25 are maintained.

FIGS. 27A and 27B are views for explaining an example in which the ink container portion can be separated for each color of ink in the integrated head unit as described above. FIG. 27A is an overall perspective view. (B) shows the recording head unit 111 of the head unit 110 and the ink container units 112 (112Y, 112) of each color.
(M, 112C) is shown in a perspective view. The advantage of doing this is that in color image printing,
Since the Y, M, and C inks are not necessarily consumed at the same speed, in the example of FIGS. 25 and 26, even if other ink remains when one of the inks runs out, the head unit Alternatively, the entire integrated ink container must be replaced, which is disadvantageous in terms of running costs. However, the separate ink containers for each color as in the present invention eliminates only the ink container. The replacement realizes a further reduction in running cost.

Specific Example 400 dpi on a 28 mm × 7 mm silicon chip.
With an array density of 128, 128 ejection elements (heating elements, ejection ports, etc.) for Y, 128 for M, and 128 for C were formed in one row. The center distance between the two ejection elements where the Y ejection element and the M ejection element are located is 95.25 μm, and the center distance between the two ejection elements where the M ejection element and the C ejection element are located is 158. It was 75 μm. In other dimensions, the heating elements are all 120μ
m × 28 μm (108Ω), discharge port size is 28 μm ×
28 μm. Using such a head chip,
When color printing was performed, the timing of ink ejection in the carriage scanning direction was shifted by about 32 μm on the recording paper between the group of Y and M ejection port arrays and the ejection port array of C. When performing color mixing with M and C inks, the dots of Y, M, and C do not completely overlap with each other in the x direction and the y direction, however, to the human eye, they overlap. Looks like
A good full-color recorded image can be obtained.

Comparative Example A 400 dpi image was formed on a 10 mm × 7 mm silicon chip.
At an array density of 3, three chips with 128 ejection elements formed are prepared and precisely positioned under a microscope.
Each of the ejection elements (nozzles) of the three head chips is stacked so as to form a grid, and three inks (Y, M,
A color head unit capable of ejecting C) was manufactured. Using this head unit, when combining colors with mixed colors, make sure that the inks of each color overlap at the same position,
When a full-color recorded image similar to the above example was created, compared to the above example, there was no more vividness,
It was a slightly dull image.

[0055]

[0056]

[0057]

[0058]

[0059]

[0060]

[0061]

As is apparent from the above description, the present invention
According to the above, the following effects are obtained. According to the first aspect of the present invention, a plurality of heating elements are grouped for each color on a common substrate on a thermal energy action section for ejecting a plurality of color inks for color recording. Since they are formed for each color, compactness and low cost are realized (common one).
Effect of one substrate). In addition, by adopting this configuration, the orifices corresponding to the respective colors can be arranged in a straight line on the same plane, and the discharge orifice area is very small, so that the discharge orifice area is protected by a cap or the like. The reliability maintenance mechanism also
Can be very compact. Furthermore, according to the present invention, with this configuration, orifices corresponding to each color are arranged in a straight line, and the positional accuracy is determined by the accuracy of the heating element substrate manufacturing, but is composed of a separate heating element substrate for each color,
In the case of a color head unit in which separate heads are arranged for each color, the positional accuracy of the orifice depends on the assembly accuracy for assembling separate heads for each color. It is very difficult to assemble with high accuracy, and in such a color head unit, it is difficult to obtain a good orifice position accuracy. The positional accuracy of the orifice can be obtained with the precision of the body substrate fabrication, and the precision can be made very high because the heating body substrate fabrication is the same as the semiconductor fabrication process.

The second aspect of the present invention is a color head unit for ejecting a plurality of color inks, and has a structure of an ink jet head integrated with an ink container. In the thermal energy action section, a plurality of heating elements are formed in groups for each color on one common substrate, and all the functions are concentrated on one heating element substrate. The heating element substrate, in other words, the recording head is very expensive. Generally, in a monochrome ink container-integrated ink jet head, when the ink runs out, the head is generally discarded together with the ink container.
And since it is a monochrome ink container integrated type ink jet head, such a thing (disposing of the head together with the ink container) is possible without any problem in terms of profitability, but as in the present invention, In an expensive color head unit, the color head unit is very expensive. Therefore, from the viewpoint of running cost, it is better that the color head unit can be used many times even if the ink runs out. By paying attention to this point, the present invention can realize a low running cost by allowing only the ink container portion, which is a consumable, to be detachable from the recording head portion without making the expensive color head unit disposable once.

Effects corresponding to claim 3 : In a color head unit for ejecting inks of a plurality of colors, the consumption speed of the ink is not always the same for all the colors, but usually differs for each color. Therefore,
According to the present invention, not only the ink container can be detachably attached to the recording head at the same time, but also the ink container can be detached for each color, and only the ink container of the missing color can be replaced, thereby further lowering running. The cost was realized.

[0064] 4. the corresponding effect: In the present invention, in the color head unit for ejecting a plurality of color inks, thermal energy acting portion of the common 1
A plurality of heating elements are formed in groups for each color on a single substrate, and not only are all the functions integrated on one heating element substrate, but also a plurality of Since the flow path and the liquid chamber are made of a flow path substrate formed by integral molding of plastic, heads of each color are assembled, with separate heat generation substrates for each color and separate flow path substrates for each color. In addition to significantly lowering the assembly cost as compared to the color head unit that is made, the flow path substrates for each color are formed by integral molding of plastic. It was possible to obtain a color head unit having very high orifice position accuracy without any deviation.

[0065] 5. the corresponding effect: In the present invention, in the color head unit for ejecting a plurality of color inks, thermal energy acting portion, a plurality of heat generating for each color a common single substrate The body is formed in a group, and not only all the functions are integrated in one heating element substrate, but also the channels and liquid chambers for multiple colors provided corresponding to it are integrally molded with plastic. The orifice rows corresponding to each enclosure were perforated in a straight line with an excimer laser in a common plate-shaped plastic area. The cost of forming the orifice array can be significantly reduced as compared with a color head unit in which the heads of the respective colors provided with the flow path substrates are assembled. further,
Since a common plate-shaped plastic area is perforated in a straight line with an excimer laser, the orifice position accuracy is not disturbed during assembly as compared to the conventional color head unit that forms an orifice row for each color. A color head unit having very high orifice position accuracy was obtained.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining the operation of an inkjet head as an example of an inkjet head to which the present invention is applied.

FIG. 2 is a diagram illustrating a configuration example of a main part of the inkjet head illustrated in FIG. 1;

FIG. 3 is a diagram for explaining one process of a manufacturing process of the ink jet head applied to the present invention.

FIG. 4 is a view for explaining another process of manufacturing the ink jet head applied to the present invention.

FIG. 5 is a view for explaining still another one of the manufacturing steps of the ink jet head applied to the present invention.

FIG. 6 is a view for explaining still another one of the manufacturing steps of the ink jet head applied to the present invention.

FIG. 7 is a view for explaining still another one of the manufacturing steps of the ink jet head applied to the present invention.

FIG. 8 is a view for explaining still another one of the manufacturing steps of the inkjet head applied to the present invention.

FIG. 9 is a view for explaining still another one of the manufacturing steps of the ink jet head applied to the present invention.

FIG. 10 is a view for explaining still another one of the manufacturing steps of the ink jet head applied to the present invention.

FIG. 11 is an overall perspective view showing another example of the ink jet head applied to the present invention.

12 is an exploded perspective view of the inkjet head shown in FIG.

13 is a perspective view of the flow path substrate shown in FIG. 12 as viewed from the back.

FIG. 14 is an exploded perspective view for explaining another example of the inkjet recording head applied to the present invention.

FIG. 15 is a main part configuration diagram for explaining another example of an ink jet recording head applied to the present invention.

FIG. 16 is a main part configuration diagram for explaining still another example of an ink jet recording head applied to the present invention.

FIG. 17 is a main part configuration diagram for explaining still another example of an ink jet recording head applied to the present invention.

FIG. 18 is a perspective view of an essential part showing an example of an ink jet head according to the present invention.

FIG. 19 is a diagram illustrating an example in which an ink tank is provided in the inkjet head illustrated in FIG. 18;

FIG. 20 is a diagram illustrating an example of a case where recording is performed using the inkjet head according to the present invention.

FIG. 21 is a diagram for explaining the operation principle of the ink jet according to the present invention.

FIG. 22 is a diagram for explaining formation of recording dots by the inkjet head according to the present invention.

FIG. 23 is a perspective view showing another example of the inkjet head according to the present invention.

FIG. 24 is a view for explaining the operation principle when the ink jet head shown in FIG. 23 is used.

FIG. 25 is a view for explaining another example of the ink jet head applied to the present invention.

FIG. 26 is a view for explaining another example of the ink jet head applied to the present invention.

FIG. 27 is a view for explaining another example of the ink jet head applied to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Ink 2, Meniscus, 3 ... Heating element, 4 ... Microbubble, 5 ... Bubble, 6 ... Ink column, 7 ... Constricted part, 8 ... Flying ink droplet, 10 ... Recording head, 11 ... Electrothermal converter, 1
Reference numeral 2 denotes a substrate, 13 denotes a grooved plate, 14 denotes an orifice, 15 denotes a liquid discharge port, 16 denotes a heat acting portion, 17 denotes a heat generating portion, 18 denotes a heat acting surface, 19 denotes a lower layer, and 20 denotes a heating resistor layer. ... upper layer, 22, 23 ... electrode, 30 ... substrate, 31 ... ink discharge pressure generating element, 32 ... thin film layer, 33 ... resist layer, 34 ...
Photomask, 35: ink channel groove, 36: ink channel, 37: common liquid chamber, 40: flat member, 41: dry film resist layer, 42: ink inlet, 51: channel substrate, 52: heat generation Body substrate, 53 ... Ink inlet, 54 ...
Discharge port, 55: channel groove, 56: common liquid chamber, 57: individual lead electrode, 58: common lead electrode, 59: heating element, 61
... Head holding board, 62 ... Hole, 63 ... Adhesive, 65 ... Holding spring, 66 ... Claw, 67 ... Hole, 70 ... Flow path board, 71 ...
Common liquid chamber forming recess, 72a, 72b: ink flow path forming groove, 73: orifice plate, 74a, 74b: ink discharge port, 75: heating element, 76: heating substrate, 80: heating element substrate, 81Y, 81M 81C, 81B: ink ejection element, 82: ink tank, 90: recording head, 91: recording paper, 92: carriage, 93: guide rod, 94: screw rod, 95: recording paper feed roller, 96 ...
Recording paper holding roller, 100 ... head unit, 101 ...
Head chip, 102: FPC, 103: Top cover, 104
... Ink container part, 105 ... Filter, 106 ... Foam material for ink impregnation, 107 ... Bottom cover, 110 ... Head unit, 111 ... Head part, 112 ... Ink container part.

Claims (5)

(57) [Claims] An ink container for supplying a recording liquid is formed integrally with a recording head, and a thermal energy generating means for applying thermal energy to the recording liquid in a liquid chamber of the recording head. The action of the thermal energy causes bubbles to be generated in the thermal energy action section in the recording liquid, and the recording liquid flies as droplets from the ejection orifice with the acting force accompanying the increase in the volume of the bubbles, and adheres to the recording surface. in the ink container-integrated ink-jet head for recording, the ink jet head, ejecting a plurality of colors recording liquid
The recording head section to be printed has a plurality of colors.
Install the ink container that supplies the recording liquid on the carriage together.
Ink jet device
A plurality of heating elements for each color formed in groups on a common substrate, and a flow path and a liquid chamber are formed corresponding to the heating elements. An orifice corresponding to each color of the discharge orifice is arranged in a straight line on the same plane. Wherein said ink container is an ink container integral ink jet head according to claim 1, characterized in that the detachable and the recording head portion. Wherein the ink container, according to claim 1, wherein said recording head portion is detachable for each color
Or the ink jet head integrated with an ink container according to any one of 2 . Wherein said flow path substrate, the flow path of the plurality of color separation, the liquid chamber, according to claim 1 or 2 or 3, characterized in that a channel substrate formed by integral molding of plastic Ink jet head with integrated ink container. Wherein said discharge orifice, orifice array corresponding to each color, an excimer laser on a common plate-shaped plastic region, to any one of claims 1 to 4, characterized in that it is perforated in line The inkjet head integrated with the ink container described in the above.