JPH0839805A - Ink jet head and ink jet recording apparatus - Google Patents

Abstract

PURPOSE:To stably emit ink without occurring the color mixture even when an ink emitting amt. is different by differentiating the shapes of the water repelling region and hydrophilic region of an emitting orifice surface corresponding to the difference of the shape of an emitting orifice or the difference of the kind of ink. CONSTITUTION:A heater board 100 is bonded and fixed to a support substrate 300 by an adhesive and a grooved top plate 1300 is temporarily bonded to the heater board 100 so that the heater part as the ink emitting piezoelectric element arranged on the heater board 100 coincides with the ink passage 8 of the grooved top plate 1300 and fixed by the mechanical energizing force of a press spring 500. The orifice plate 400 possessed by the grooved top plate 1300 is arranged to the front end surface of the support substrate 300 like an apron. Ink is supplied to the ink supply port provided to the upper part of the grooved top plate 1300 from an ink supply member 600 and the ink supply member 600 has a protruding rod and is fixed to the support substrate 300 by inserting the protruding rod in the through-hole of the support substrate 300 to thermally caulk the same.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink repellent and lyophilic treatment for an ink ejection port forming surface of an ink jet head in an ink jet recording apparatus for ejecting ink from a recording head onto a recording medium to perform recording on the recording medium. It is a thing.

[0002]

2. Description of the Related Art Among various currently known recording systems, it is a non-impact recording system that produces almost no noise during recording, is capable of high-speed recording, and requires special fixing on plain paper. It is recognized that the ink jet recording method that can perform recording without doing so is an extremely effective recording method.

In general, it is preferable that the ink droplet ejection direction in the ink jet recording system is stable, and various efforts are being made to perform various treatments on the ink ejection port forming surface so as to eject the ink stably.

As described in Japanese Patent Application No. 5-259981, a small amount of ink called mist that accompanies a main ink droplet adheres to the periphery of an ink ejection port, and the ink mist coalesces. As for the problem of growing around the ink ejection port and being drawn into the ink ejection port to cause ejection failure, an invention has been made in which a water repellent region and a hydrophilic region are provided on the ink ejection port forming surface.

[0005]

SUMMARY OF THE INVENTION In order to obtain an optimum image for each of a multicolor image formed by a plurality of color inks and a single color image formed by a single color ink, an optimum image can be obtained. In the case of an inkjet recording device that optimizes the ink ejection amount by changing the size etc., the state of the ink mist adhering to the vicinity of the ink ejection port is different depending on the size of the ink ejection port, the ink ejection amount, and the ink type. Therefore, if a hydrophilic region having the same shape is provided on the ink ejection port forming surface, stable ink ejection may not be possible regardless of the size of the ink ejection port, the ink ejection amount, and the type of ink.

Further, in the case of integrally forming a plurality of color ink ejection ports on the same substrate, it may not be possible to sufficiently prevent color mixing simply by providing a hydrophilic region having a conventional shape.

Therefore, according to the present invention, the size of the ink ejection port is
An object of the present invention is to provide an ink jet head and an ink jet recording apparatus that can achieve stable ink ejection without color mixture according to the difference in ink and / or ink ejection amount.

[0008]

SUMMARY OF THE INVENTION The present invention is an ink jet head for recording by using at least one of a plurality of ejection ports for ejecting different amounts of ink or a plurality of different types of ink. An inkjet characterized in that the shapes of the water-repellent area and the hydrophilic area of the ejection port surface on which a plurality of ejection ports for ejection are arranged differ depending on the difference in the ejection port shape and the type of ink. Provided is a head and an inkjet recording apparatus having one or more inkjet heads mounted therein.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the accompanying drawings.

(Embodiment 1) First, FIGS. 1 and 2 show a specific example of an essential part of an ink jet head IJH used in the present invention. As shown in FIG. 1, the inkjet head IJH is a substrate 10 provided with an ink ejection pressure generating element.
0 (hereinafter referred to as a heater board) and its substrate 10
It is composed of a substrate 1300 having an ink chamber 7 which is joined to 0 and accommodates a recording medium (hereinafter referred to as ink) and an uneven portion (groove) which constitutes an ink path 8. This board 13
00 (hereinafter, referred to as a grooved top plate) integrally has an orifice plate 4 having an ink ejection port 9 for ejecting ink communicating with the ink passage 8.

The heater board 100 is a support substrate 300.
The grooved top plate 1300 is bonded and fixed on the heater board 100 with an adhesive, and a heater portion as an ink discharge pressure generating element disposed on the heater board 100, and an ink path 8 of the grooved top plate 1300. The orifice plate 400 of the grooved top plate 1300, which is fixed by the mechanical biasing force of the temporarily-bonded back-pressing spring 500, is arranged on the front end surface of the support substrate 300 like a front drop. To be done.

Ink is supplied from the ink supply member 600 through the ink supply port 2a provided in the upper portion of the grooved top plate 1300. The ink supply member 600 has a protrusion bar (not shown) and is provided on the support substrate 300. It is fixed to the support substrate 300 by inserting a protruding rod into the provided through hole and caulking it with heat.

1 and 2, the ink supply member 600, the heater board 100, the gaps 10a and 10b in the grooved top plate 1300, and the orifice plate 400.
The sealant is poured as a bonding space in the bonding area where a slight gap is provided so that the sealant between the support substrate 300 and the front end surface of the support substrate 300 can be poured. The groove 3A may be any groove as long as it can sufficiently encapsulate the sealant.

It is important that the groove 3A provided in the support substrate 300 forms a space continuous with the gap between the orifice plate 400 and the ink supply member 600. It is not preferable that the groove 3A is completely covered with the orifice plate 400 or is independent of the gaps 10a and 10b. This is because the flow path of the injected sealant is cut off, and good sealing cannot be achieved. Groove 3A formed on the front end surface of the support substrate 3
Is formed by pressing in consideration of mass productivity.

The sealant is injected from a sealant injection port (not shown) in the upper part of the ink supply member 600 to seal a wire bonding portion (not shown) for transmitting an electric signal and at the same time as the orifice plate 400. Ink supply member 60
The gaps 10a and 10b with respect to 0 are sealed, and further, the gap region between the orifice plate 400 and the front end face of the support substrate 300 is completely sealed by passing through the groove 3A provided in the support substrate 300. Thus, in order for the sealant to seal the gap without blocking the orifice 9, a proper thixotropy and a proper viscosity are required. That is, if the viscosity of the sealant is too low, it will enter the nozzles and orifices 9 in the grooved top plate 1300 and cause clogging. On the other hand, if the viscosity is too high, the sealant will not completely flow around the orifice plate 400. The viscosity of the sealant used in the present invention is preferably 1000 to 15000 cps, more preferably 2000 to 10000 cps, and most preferably 4000 to 10000 cps.

As the sealant, the heater board 100 made of a silicon wafer and the supporting substrate 30 made of a metal are used.
0 and good adhesion to the grooved top plate 1300 made of synthetic resin, the orifice plate 400, the ink supply member 5 and the like are required. Further, in order to bond a plurality of different materials having different coefficients of thermal expansion, a soft material capable of absorbing the difference in thermal expansion due to the temperature environment, specifically, a sealing agent having a hardness of JIS standard A100 or less. Need to be used.

On the other hand, since this sealant also plays a role of covering and protecting the wire bonding portion, it must be a material that does not cause corrosion to the aluminum wire bonding portion and the aluminum electrode. In order to prevent corrosion on the electrodes and wire bonding, C in the sealant
The concentration of impurity ions such as l ⁻ and Na ⁺ is preferably 30 ppm or less. Such materials are required to have properties such as excellent ink resistance, particularly solvent resistance and alkali resistance, in order to locally contact the ink. Furthermore, it is also necessary that the permeability to oxygen, nitrogen and water vapor is low.

Ink Jet Head Unit FIG. 3 shows an exploded perspective view of this ink jet head unit IJU, and the structure thereof will be described.

In FIG. 3, on a substrate 100 made of Si, an electrothermal conversion element (discharge heater) as a thermal energy generating element arranged in a plurality of rows and an electric power such as Al for supplying electric power thereto. The wiring and the wiring are formed by a film forming technique. The heat generated by the electrothermal conversion element causes film boiling in the ink, and bubbles are generated thereby, so that the ink is ejected. The wiring board 200 has wirings (for example, connected by wire bonding) corresponding to the wirings of the heater board 100, and pads located at the ends of the wirings and receiving electric signals from the main body device.

The grooved top plate 1300 has a groove for forming a partition wall for partitioning a plurality of ink paths as described above, a supply liquid chamber for accommodating ink supplied to each ink path, and the like. An ink supply port 150 that has the ink supplied from the ink tank and is introduced into the common liquid chamber described above.
0 and an orifice plate 400 having a plurality of ejection openings corresponding to the respective ink paths are integrally provided.

The support 300 supports the back surface of the wiring board 200 on a plane and is made of a metal such as Al. The rear pushing spring 500 presses the portion corresponding to the common liquid chamber of the top plate with a light pressure at the center of the M shape in the M shape, and the front drooping portion 501 corresponds to the portion corresponding to the ink path, preferably in the vicinity of the ejection port. Concentrate the area with linear pressure. The heater board 100 and the top plate 1300 are engaged with each other in a state in which they are sandwiched by engaging the foot portion of the presser spring with the back surface side of the support body 300 through the holes 1901 and 1902 of the support body 300. The heater board 100 and the top plate 1300 are pressure-bonded to each other by the concentrated biasing force of the presser spring 500 and its front hanging portion 501. The wiring board is attached to the support 300 by adhesion with an adhesive or the like. The ink supply path member 600 forms an ink conduit 1600 that is continuous with the ink supply pipe 2200 as a cantilever with the supply pipe 2200 side fixed.
A sealing ball 602 is inserted to ensure a capillary action with respect to 00. A filter 7 is attached to the tank side end of the supply pipe.
00 is provided.

Since the ink supply passage member 600 is molded, the ink supply passage member 600 is relatively inexpensive and has high positional accuracy, which not only suppresses a decrease in manufacturing accuracy, but also cantilevered conduit 16
With 00, the pressure contact state of the conduit 1600 to the ink supply port 1500 can be stabilized even during mass production. In this example, a more complete communication state can be reliably obtained by simply pouring the sealing adhesive from the ink supply path member side under this pressure contact state. The ink supply path member 6
The fixing of No. 00 to the support 300 is performed by fixing the back side pins (not shown) of the ink supply path member 600 to the holes 301, 302 and 303 of the support 300 to the support 30 as described above.
This can be easily performed by projecting through through the 0 holes 301, 302, and 303 and heat-sealing the portion projecting to the back surface side of the support 300.

FIG. 4 is an exploded perspective view of an ink jet head equipped with a plurality of ink jet head units according to an embodiment of the present invention.

The ink jet head of this embodiment is equipped with four recording heads capable of ejecting inks of different colors, and the positional relationship between these recording heads can be accurately determined. The four recording heads may eject ink of the same color. In this case,
High-speed recording or gradation expression according to the number of ink droplets is possible, and gradation recording is also possible by ejecting inks of the same color but different densities.

In FIG. 4, reference numeral 4000 indicates a unit frame. The unit frame 4000 is a U-shaped outer wall plate 4001.
And a head holding unit 40 for housing each recording head unit
It comprises three inner wall plates 4002 which limit 03. Figure 1
The print head IJU described in No. 3 has its head holding section 400 with its ink ejection port directed downward in the drawing.
It is stored in 3. To position each recording head in the unit frame 4000, the reference surfaces provided in each recording head are abutted against the three-direction reference surfaces provided in each head holder, and then fixed with an adhesive or the like. In this case, in each recording head unit IJU, the positional relationship between the reference surface and the orifice needs to be set with high accuracy. Thus, according to this embodiment, four recording head units are provided. Since the recording heads are adhesively fixed to the unit frame and the recording heads are replaced for each unit, the positional relationship between the four recording heads does not shift due to the mounting operation at the time of replacement.

The upper housing 4506 and the side housing 4006 are fixed to the unit frame 4000, respectively. When the upper housing is fixed, a pair of pins 4504 (one of which is not shown) provided on the upper housing is fixed to the unit frame 40.
4011 provided on the upper end surface of the outer wall plate 4001
Upper housing 450 when fixed by being inserted into
6 and the protrusions (not shown) on the retaining plates 4505 formed at both ends of the upper housing are engaged with the recesses 4010 formed in the outer wall plate with the elastic biasing force of the retaining plates 4505. The side housing 4006, which is fixed by being stopped, is fixed to the unit frame by the housing 40.
The same as the upper housing 4506, using a pair of retaining plates 4008 and the recess 4007 of the unit frame 4000.

A plurality of pads 4502 as electric contacts on the recording head IJU side are provided in a portion corresponding to the outer surface of the upper housing 4506, and each of the pads 4502 extends from the rear surface side of the upper housing 4506.
It is connected to 501. When the housing 4506 is fixed to the unit frame, the respective terminals 4501 come into contact with the corresponding connection pads on the substrate of the recording head.

The side housing 4006 has a hole 4 for inserting the ink supply tube 2200 of the recording head IJU.
009 is formed.

FIG. 5 is a perspective view showing the connection between the recording head shown in FIG. 4 and each ink tank.

As shown in FIG. 5, the ink tank 6000 corresponding to each ink color is formed by individually inserting the ink supply pipes 2200 of the corresponding recording heads into the openings of the joint portion (not shown). Connect to the recording head. Also, when the ink tank 6000 is removed from the recording head, it is possible to individually remove each ink tank of each ink color.

FIG. 6 is an external perspective view of an ink jet recording apparatus IJRA capable of mounting the recording head shown in the above embodiment.

In FIG. 6, the forward and reverse rotations of the drive motor 5013 are transmitted to the lead screw 5004 via the drive force transmission gears 5011 and 5009, and the lead screw 5004 is rotated.
Further, the carriage HC has a pin (not shown) that engages with the spiral groove 5005 of the lead screw 5004. As a result, the carriage HC is reciprocated in the longitudinal direction of the device. Reference numeral 5002 denotes a cap that caps the front surface of each recording head in the recording head, and is used to perform suction suction recovery of the recording head through an opening in the cap by suction means (not shown). The cap 5002 can be moved by the driving force transmitted via the gear 5008 or the like to cover the ejection port surface of each recording head. A cleaning blade (not shown) is provided near the cap 5002, and the blade is supported so as to be movable in the vertical direction in the drawing.
Needless to say, the blade is not limited to this form, and a known cleaning blade can be applied to this example.

The capping, cleaning, and suction recovery are configured so that desired processing can be performed at their corresponding positions by the action of the lead screw 5004 when the carriage moves to the home position, but at known timing. Any one can be applied to this example as long as a desired operation is performed.

The connection pad 4502 of the recording head unit mounted on the carriage HC is connected to the connection pad 5031 of the carriage HC by rotating the connection plate 5030 provided on the carriage HC around a predetermined axis, and an electrical connection is made. Done. As will be described later, since no connector or the like is used for this connection, unnecessary force does not act on the recording head unit.

An example in which the present invention is applied to the recording head unit of the ink jet recording apparatus described above will be described below.

FIG. 7 is a view of the ink jet head shown in FIG. 4 as seen from the orifice plate 400 side.
In this embodiment, IJU20 is black and IJU3 is
Cyan, magenta, and yellow IJUs are attached to 0, 40, and 50, respectively.

Recording of a multicolor image (also referred to as "color image") by the ink jet recording method usually uses four color inks of yellow, magenta, cyan and black, and droplets of these inks are recorded on a recording medium. Discharge to
This is performed by mixing them on the recording medium. At this time, the weight of the ink droplet, that is, the ejection amount is
If the value is small, the recording density of the color image is low, and if the value is large, the bleeding or the difference in recording by color mixing (color mixture of yellow and magenta, color mixture of magenta and cyan, color mixture of cyan and yellow) is different. Bleeding becomes more intense at the color boundary, and the quality of the color image deteriorates. At the time of forming a color image, it is necessary to set an optimum ink ejection amount that does not cause decrease in recording density and bleeding or bleeding during mixed color recording.

However, when a monochromatic image (also referred to as a "monochrome image") is formed with a monochromatic ink, if the ink ejection amount is left as it is during the formation of the color image, the recording density of the monochromatic image is It becomes too low to obtain the optimum image.

Therefore, in the present embodiment, the size of the ink ejection port 9 of the black ink ink jet head unit IJU20 is set to the other ink jet unit IJU.
It is made larger than the ink discharge ports 9 of 30, 40, and 50, and the black ink discharge amount is set to about twice the discharge amount of other inks to suppress the decrease in the recording density of a monochrome image and obtain an optimum image. I am allowed to do so.

FIG. 8 shows the water repellent and hydrophilic shapes on the ink ejection port forming surface of the ink jet head portion of the present invention.

After the water-repellent treatment is applied to the surface of the grooved top plate 1300 where the ink ejection ports are formed, the water-repellent film 8 is formed by thermosetting.
1 is formed. After that, when the excimer laser is irradiated through the mask in which the portion corresponding to the hydrophilic portion shown in the figure is opened on the ejection port forming surface, the hydrophilic portions 84 and 85 are partially formed. After that, the nozzle 89 is formed by irradiating an excimer laser from the back side of the ejection port forming surface. The dotted line portion 82 on the ejection port forming surface is the inner side edge of the cap contact portion of the inkjet recording apparatus.

The effect of providing the hydrophilic portion inside the cap abutting portion has already been known in Japanese Patent Application No. 5-259981.

In many cases, the material of the grooved top plate 1300 must be selected from the limited materials due to restrictions such as moldability and ink wettability, but in this embodiment, polysulfone is used. ing. As the water repellent, CYTOP CTX-105 (manufactured by Asahi Glass) or CYTOP CTX-805 (manufactured by Asahi Glass) is used, and the thickness thereof is about 0.1 to 0.2 μm. The water repellent application range is
Here, a certain application range including the cap contact range is specified instead of the front surface of the ejection port forming surface, but this is to prevent backing during application of the water repellent and during drying. In this embodiment, since the cap contact area is A, B, and C at the position of 0.6 mm, the water repellent application area is A, B, and C.
Both B and C are coated with 0.5 mm. However, if there is no concern about the backside, it may be applied to the entire surface on which the ejection port is formed.

After forming the water-repellent film 81, on the discharge port forming surface side,
Excimer laser is irradiated from the ejection port forming surface side to form the hydrophilic portions 84 and 85. The irradiation method at this time may be either a contact mask method or a projection mask method.

Band-like hydrophilic regions 4 are formed in parallel to the ejection port array direction and on both sides of the ejection port array. Distances W ₁ and W ₂ from the discharge port to the hydrophilic area 84, width H of the hydrophilic area
_{Although 1} and H ₂ are selected according to the type of ink, the diameter of the ejection port, etc., it is desirable that the distance W is 1 to 2 times the diameter of the ejection port and the width H is 0.2 mm or more. Further, the length L is preferably equal to or longer than the length of the ejection port array.

The hydrophilic region 85 is formed in an island shape around the above-mentioned strip-shaped hydrophilic region 84. The island part is a hydrophilic part. The shape of the island does not matter as long as the water-repellent area is 30% or more, but the corner is preferable to the circle in order to suppress the movement of the ink.

In this embodiment, the black nozzle diameter is 35 μm.
m, W ₁ and W ₂ are 0.8 mm, H ₁ and H ₂ are 0.94
When the hexagonal area was 0.15 mm ² and the hydrophilic area area was 40%, good printing was obtained without ejection failure on 5 A4 solid sheets (no blade in the middle). .

The nozzle diameter of the color is 27 μm, and W ₁
Is 0.435 mm, W ₂ is 0.37 mm, H ₁ is 0.04
mm, H ₂ is 0.105, and island shape is 0.08 m
When m ² and the hydrophilic region area were about 40%, good printing was obtained as with black.

(Second Embodiment) FIG. 9 shows another example of the present invention. As shown in this figure, in the case of the present embodiment, the ink ejection pressure generating elements corresponding to the four color inks are integrally formed on one substrate.

Symbols in the figure will be described. Reference numeral 60 denotes the entire head, 69 denotes a head for a black image,
Reference numeral 70 is a head for printing a color image, and inks of three colors are formed on one substrate in a state where the liquid chambers are separated. Reference numeral 61 is an orifice for ejecting black ink, and 62, 63, 64 are orifices for ejecting cyan ink, magenta ink, and yellow ink, respectively. Further, reference numerals 65 to 68 are ink supply tubes for supplying ink to the respective heads, and supply the respective inks to the corresponding heads. 71
Is connected to a main body (not shown) by a flexible cable that sends a print signal to each head.

Similar to the first embodiment, the ejection port 6 for black ink is used.
Is formed larger than the other ink ejection ports 62 to 64,
It is designed to increase the ink ejection amount. The shape of the hydrophilic portion provided on the ink ejection port forming surface of each color is optimally formed according to the ejection amount of each ink, as in the first embodiment.

Furthermore, by providing the partition 72 between the colors, in the case of a head having a structure in which the ejection ports of a plurality of colors are integrally formed on one substrate, it is possible to more effectively prevent the color mixing between the colors. The color partitions 72 are formed simultaneously by an excimer laser, like other hydrophilic portions. The method of forming the inter-color partitions 72 is not limited to the processing by the excimer laser, and may be formed by providing convexes or concaves when forming the grooved top plate. That is, it is only necessary to have a function of limiting the movement of ink between colors.

The difference in the discharge amount between the above embodiments,
An example has been described in which the shapes of the water-repellent region and the hydrophilic region on the surface on which the ejection ports are arranged differ depending on the ejection port diameter and the type of ink.

Here, the difference in the shapes of the water repellent area and the hydrophilic area for each difference will be described.

When the ink ejection ports are different, it is desirable that the head portion with a large ink ejection amount has a larger total area of the hydrophilic portion.

When the ejection port diameters are different, it is desirable to increase the distance from the center of the ejection port to the hydrophilic portion in a head having a larger ejection port diameter.

When the types of ink are different, for example, the head portion using ink having high wettability (ink having a small contact angle with the water-repellent surface) has a longer distance from the circumference of the ejection port to the hydrophilic portion. Is good.

As a result, even if an ink droplet adheres to the surface on which the ejection port is arranged, the influence on the nozzle can be prevented.

The present invention brings excellent effects particularly in an ink jet type recording head and a recording apparatus which form flying droplets by utilizing thermal energy among the ink jet recording systems.

With regard to its typical structure and principle, for example, US Pat. Nos. 4,723,129 and 4740 are applicable.
What is done using the basic principles disclosed in 796 is preferred. This method can be applied to both the so-called on-demand type and continuous type, but especially in the case of the on-demand type, liquid (ink)
By applying at least one drive signal to the electrothermal converter arranged corresponding to the sheet or liquid path in which is stored, which corresponds to the recorded information and causes a rapid temperature rise exceeding nucleate boiling. , It is effective because it generates heat energy in the electrothermal converter and causes film boiling on the heat-acting surface of the recording head, resulting in the formation of bubbles in the liquid (ink) corresponding to this drive signal on a one-to-one basis. Is. The liquid (ink) is ejected through the ejection openings by the growth and contraction of the bubbles to form at least one droplet. It is more preferable to make this drive signal into a pulse shape because bubbles can be immediately and appropriately grown and contracted, so that liquid (ink) ejection with excellent responsiveness can be achieved.

As the pulse-shaped drive signal, those described in US Pat. Nos. 4,463,359 and 4,345,262 are suitable. If the conditions described in US Pat. No. 4,313,124 of the invention relating to the rate of temperature rise on the heat acting surface are adopted, more excellent recording can be performed.

As the constitution of the recording head, in addition to the combination constitution of the discharge port, the liquid passage, and the electrothermal converter (the linear liquid passage or the right-angled liquid passage) as disclosed in the above-mentioned respective specifications. The present invention also includes configurations using US Pat. No. 4,558,333 and US Pat. No. 4,459,600, which disclose a configuration in which a heat acting portion is arranged in a bending region.

In addition, by being mounted on the apparatus main body, it can be electrically connected to the apparatus main body and can be supplied with ink from the apparatus main body by a replaceable chip type recording head or the recording head itself. The present invention is also effective when a cartridge-type recording head provided with an ink tank is used.

Further, it is preferable to add recovery means for the recording head, preliminary auxiliary means, etc., which are provided as a constitution of the recording apparatus of the present invention, because the effects of the present invention can be further stabilized. If you list these specifically,
Capping means, cleaning means, pressurizing or sucking means for the recording head, preheating means using an electrothermal converter or another heating element or a combination thereof, and a preliminary ejection mode for performing ejection other than recording It is also effective to perform stable recording.

Further, as the recording mode of the recording apparatus, not only the mainstream color such as black is recorded but also the recording head may be integrally formed or a plurality of them may be combined. The present invention is also extremely effective for a device provided with at least one of full colors by color mixing.

In the embodiments of the present invention described above, the ink is described as a liquid, but it is an ink that solidifies at room temperature or lower and softens at room temperature, or is a liquid, or the above-mentioned. In the inkjet method, the temperature of the ink itself is generally adjusted within a range of 30 ° C. or higher and 70 ° C. or lower to control the temperature of the ink so that the viscosity of the ink is within a stable ejection range. It may be in a liquid form.

In addition, the temperature rise due to thermal energy is positively prevented by using it as the energy for changing the state of the ink from the solid state to the liquid state, or the ink is solidified in a standing state for the purpose of preventing evaporation of the ink. In some cases, such as ink that is liquefied by applying heat energy according to a recording signal and ejected as a liquid ink, or one that has already started to solidify when it reaches a recording medium. The use of an ink having a property of being liquefied only by heat energy is also applicable to the present invention. In such a case, the ink is disclosed in JP-A-54-5684.
No. 7 or JP-A-60-71260, a mode in which the porous sheet is opposed to the electrothermal converter in the state of being held as a liquid or solid in the recess or through hole of the porous sheet. May be In the present invention, the most effective one for each of the above-mentioned inks is to execute the above-mentioned film boiling method.

In addition, as a form of the recording apparatus according to the present invention, in addition to one provided integrally or separately as an image output terminal of information processing equipment such as a word processor or a computer, a copying apparatus combined with a reader or the like, May take the form of a facsimile machine having a transmission / reception function.

[0069]

As described above, according to the present invention, in an ink jet recording apparatus for recording by ejecting a plurality of inks having different ink ejection amounts, the optimum ink ejection port surface for each head is determined according to the ejection amount. By giving the shape of the hydrophilic portion, more stable ink ejection can be performed.

Further, when a plurality of heads are integrated into a head unit and a partition is provided between the ink ejection ports of the respective colors, color mixing can be prevented more reliably and high quality printing can be obtained.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of a main part of an embodiment of an inkjet head of the present invention.

FIG. 2 is a front view of a main part of the head shown in FIG.

FIG. 3 is an exploded perspective view of an inkjet head unit having the main part of FIG.

FIG. 4 is an exploded perspective view of an inkjet head equipped with a plurality of ink head units according to an embodiment of the present invention.

5 is a perspective view showing the connection between the recording head shown in FIG. 4 and each ink tank.

FIG. 6 is an external perspective view of an inkjet recording apparatus capable of mounting the recording head of FIG.

7 is a view of the inkjet head of FIG. 4 viewed from the orifice plate side.

FIG. 8 is a diagram showing an example of water-repellent and hydrophilic shapes on an ink ejection port forming surface of the inkjet head portion of the present invention.

FIG. 9 is a perspective view showing another embodiment of the inkjet head of the present invention.

[Explanation of symbols]

 2a Ink supply port 3A groove 4 Orifice plate 5 Ink supply member 7 Ink chamber 8 Ink passage 9 Ink ejection port (orifice) 10a, 10b Gap 60 Whole head 61 Black ink ejection orifice 62 Cyan ink ejection orifice 63 Magenta ink ejection Orifices 64 Yellow ink ejection orifices 65 to 68 Ink supply tubes 69 Black image heads 70 Color image printing heads 71 Flexible cables 72 Color partitions 81 Water repellent films 84, 85 Hydrophilic parts 89 Nozzles 100 Heater boards 200 Wiring boards 300 Support substrates 301, 302, 303 Holes 400 Orifice plate 500 Back-pressing spring 501 Front drooping part 600 Ink supply member 602 Sealing ball 700 Filter 1300 Groove top plate 1500 Ink supply port 1600 Ink conduit 1901, 1902 Hole 2200 Ink supply pipe 4000 Unit frame 4001 Outer wall plate 4002 Inner wall plate 4003 Head holding part 4006 Side housing 4007 Recess 4008 Stop plate 4009 hole 4010 Recess 4011 hole 4501 terminal 4502 450 pad 4504 pin 4504 Stop plate 4506 Upper housing 5002 Cap 5004 Lead screw 5005 Spiral groove 5008 Gears 5009 and 5011 Driving force transmission gear 5013 Drive motor 5030 Connection plate 5031 Connection pad 6000 Ink tank

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Claims (18)

[Claims] 1. An ink jet head for performing recording using at least one of a plurality of different types of ink, or at least one of a plurality of different types of ink, the plurality of ejection ports for ejecting ink. An ink jet head characterized in that the shapes of the water repellent area and the hydrophilic area of the ejection port surface on which are arranged are different depending on the shape of the ejection port and the type of ink. 2. The ink jet head according to claim 1, wherein the ejection openings for ejecting a plurality of different amounts of ink are ejection openings having different ejection opening diameters. 3. The ink jet head according to claim 1, wherein the ejection openings for ejecting a plurality of different amounts of ink have the same ejection opening diameter. 4. The ink jet head according to claim 1, wherein the one or more hydrophilic regions are arranged in a strip shape in parallel to the arrangement direction of the ink ejection ports. 5. The ink jet head according to claim 4, wherein one or more island-shaped hydrophilic regions are provided on the ink ejection port forming surface opposite to the ink ejection port when viewed from the band-shaped hydrophilic region. 6. The ink jet head according to claim 5, wherein the island-shaped hydrophilic region has an area ratio of 30% or more in the region where the region is formed. 7. The ink jet head according to claim 5, wherein the island-shaped hydrophilic region has a polygonal shape. 8. An inkjet head having ejection ports of different diameters, wherein the distance between the ejection port and the strip-shaped hydrophilic region is
The inkjet head according to claim 2, wherein the diameter is 1 to 2 times the diameter of the ejection port. 9. The inkjet head according to claim 4, wherein the width of the strip-shaped hydrophilic region is 0.2 mm or more. 10. The ink jet head according to claim 4, wherein the length of the strip-shaped hydrophilic region is equal to or longer than the length of the ink ejection port array. 11. The ejection of the ink is performed by an electrothermal converter for generating heat by applying electric energy and causing the ink to change state and ejecting the ink. Inkjet head according to item. 12. The ink ejection energy generating elements corresponding to the ejection ports ejecting the plurality of different amounts of ink or the ink ejection energy generating elements corresponding to the different types of ink are integrally formed on one substrate. The ink jet head according to any one of claims 1 to 11, wherein: 13. The ink jet head according to claim 1, further comprising a plurality of head portions that eject different amounts of ink or different types of ink, and the plurality of head portions are integrated. 14. The ink jet head according to claim 1, wherein a partition is provided between the ejection ports having different ejection amounts or between the ejection ports having different types of the ink. 15. The partition is a concave groove.
The described inkjet head. 16. The partition is a convex wall.
The described inkjet head. 17. The inkjet head according to claim 14, wherein the partition is a band-shaped hydrophilic region. 18. An ink jet recording apparatus comprising the ink jet head according to claim 1 and a means for conveying a recording medium.