JPH03101962A - Ink jet recording head - Google Patents

Abstract

PURPOSE:To obtain a high-quality printing without a satellite printing by a method wherein at least one part of an orifice plate is brought into contact with a heating element mounting surface, and a flow path is extended from a heat application part along a delivery port center line and narrowed at a deliverly port orifice. CONSTITUTION:A direction that a liquid 3 flows from a supply flow path 6 into a heat application part 5 differs from a direction that the liquid 3 flows from the heat application part 5 toward a delivery orifice 2. A surface on which a heating element 4 is mounted coincides with the inner surface of the delivery port 2. The flow path is symmetrically extended from the heat application part 5 along a delivery port center line and narrowed at the delivery port orifice. An axis YO is obtained by rotating a center line XO of the supply flow path 6 in the vicinity of the heat application part 5 leftward through an angle thetaabout a point 0. The heat application part 5, the supply flow path 6, and the delivery orifice 2 are disposed so as to form an angle theta between the XO and the YO, which is in parallel to the direction that the liquid 3 flows from the heat application part 5 toward the delivery orifice 2. The condition of 90 deg.<=theta<=180 deg. is preferable, and 135 deg.<=theta<=177 deg. is preferable.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an apparatus that performs recording by discharging liquid from a discharge port by the action of thermal energy.

[Conventional technology]

Conventionally, inkjet recording devices eject micro droplets by generating a pressure change in the liquid flow path by deforming a piezoelectric element, or are equipped with a pair of electrodes that deflect the droplets and eject them. It is known what causes

In addition, various proposals have been made in which bubbles are generated by rapidly generating heat from a heating element disposed in the liquid path, and droplets are ejected from the ejection port by the generation of the bubbles.

Among these, inkjet recording heads that eject recording liquid using thermal energy are capable of discharging recording droplets and arranging orifices in high density to form flying droplets. Secondly, it is possible to perform high-resolution recording, it is easy to make the overall recording head compact, and IC technology and micro-processing technology, which has recently made significant advances in technology and improved reliability in the semiconductor field, Since it is easy to make long and planar (two-dimensional) products, it is easy to make multi-nozzles and high-density packaging, and the productivity in mass production is high. It is attracting particular attention as it can be manufactured at low cost.

In the above-mentioned inkjet recording head, ejection efficiency,
For the purpose of providing a device with excellent ejection responsiveness or ejection stability, long-term continuous recording performance, and high-speed recording performance, Japanese Patent Application Laid-Open Nos. 55-59975, 55-59976, and 59977-1988 have been published. A specific example is disclosed in the Sho Publication.

〔the purpose〕

The present invention has been made with the aim of further improving the ejection efficiency of these proposals. Another object of the present invention is to provide a high-density multi-orifice type device that is easy to manufacture and has extremely high productivity during mass production. Another object of the present invention is to provide an apparatus that can provide high quality printing without satellite printing (misalignment between the landing points of the main droplet and the satellite droplet of flying ink droplets).

[Summary of the Invention] The inkjet recording head of the present invention includes an ejection port for ejecting liquid in a predetermined direction, a heating element, and a heat effecting part that is a part where thermal energy generated from the heating element acts on the liquid. , a recording head having a supply flow path for supplying liquid to the heat acting section; drive signal generating means for generating a drive signal for driving the heating element to eject the liquid in a predetermined direction; The direction in which the liquid flows into the heat acting section from the supply channel is different from the direction in which the liquid flows out from the heat acting section toward the discharge port, and at least one of the heating element installation surface and the orifice plate parts are in contact with each other, and a flow path extends symmetrically from the heat acting part along the center line of the discharge port, and is narrowed by the discharge port orifice.

In the device of the present invention configured in this manner, thermal energy is effectively used to discharge the liquid, and the discharge efficiency is significantly improved.

Furthermore, the device of the present invention is extremely simple in structure,
Because micromachining can be easily performed, the recording head itself can be made much smaller than before, and its simple structure and ease of processing make it extremely easy to create high-density multi-orifices, which is essential for high-speed recording. It can be achieved.

Further, in the apparatus of the present invention, since the liquid flow path extends symmetrically in the ejection direction along the center line of the ejection port, it is possible to perform high-quality recording without satellite printing.

[Example] Figs. 2 to 6 show a preferred inkjet unit IJU and inkjet head IJH to which the present invention is implemented or applied. Ink tank IT, inkjet cartridge IJC, inkjet recording device body IJRA
, carriage HC and their relationships. The configuration of each part will be explained below using these drawings.

As can be seen from the perspective view in Fig. 3, the inkjet cartridge IJC in this example has a large ink storage ratio, and the tip of the inkjet unit IJU protrudes slightly from the front surface of the ink tank IT. It has a shape. This inkjet cartridge IJC is fixedly supported by a positioning means and electrical contacts (described later) of a carriage HC (FIG. 5) placed on the inkjet recording apparatus main body IJRA, and is detachable from the carriage HC. It is a disposable type. The configurations shown in FIGS. 2 to 6 of this example are those to which a number of novel techniques developed at the stage of the establishment of the present invention are applied, so while briefly explaining these configurations,
I will explain the whole thing.

(i) Inkjet unit IJU structure description The inkjet unit IJU is a bubble jet unit that performs recording using an electrothermal transducer that generates thermal energy to cause film boiling in ink in response to an electrical signal. It is.

In Fig. 2, reference numeral 100 is composed of electrothermal converters (discharge heaters) arranged in a plurality of rows on a Si substrate, and electrical wiring such as A1 for supplying electric power to the converters, which are formed by film-forming technology. It's a heater board.

200 is a wiring board for the heater board 100;
Wiring corresponding to the wiring of the heater board 100 (for example, connected by wire bonding) and a pad 201 located at the end of this wiring and receiving electrical signals from the main device.
It has

1300 is a grooved top plate provided with partition walls for dividing a plurality of ink channels and a common liquid chamber for storing ink to supply ink to each ink channel, and is supplied from an ink tank IT. An ink receiving port 1500 that receives ink and introduces it into the above-mentioned common liquid chamber, and an orifice plate 400 having a plurality of ejection ports corresponding to each ink flow path are integrally molded. Although polysulfone is preferable as the integrally molded material, other resin materials for molding may also be used.

Reference numeral 300 denotes a support made of metal, for example, which supports the back surface of the wiring board 200 on a flat surface, and serves as a bottom plate of the inkjet unit. Reference numeral 500 denotes a pressing spring, which has an M-shape and presses the common liquid chamber with light pressure at the center of the M-shape, and uses a front sag 501 to concentrate linear pressure on a part of the liquid path, preferably in the area near the discharge port. Press. The feet of the springs that press the heater board 100 and the top plate 1300 pass through the holes 3121 of the support body 300 and engage with the back side of the support body 300, thereby engaging them in a state where they are sandwiched between them. The heater board 100 and the top plate 1300 are crimped and fixed by the concentrated biasing force of the pressing spring 500 and its front sagging portion 501. Also, support body 3
00 is two positioning protrusions 101 of the ink tank IT
2 and protrusions for positioning and heat sealing retention 1800.180
Positioning hole 312, 1900.2000 that engages with 1
In addition, it has protrusions 2500 and 2600 on the back side for positioning the apparatus main body IJRA with respect to the carriage HC. In addition, the support 300 also has a hole 320 that allows an ink supply pipe 2200 (described later) to pass therethrough, which allows ink to be supplied from an ink tank. Support body 300
The wiring board 200 is attached to the board by adhering it with an adhesive or the like.

Note that the recesses 2400 and 2400 of the support body 300 are provided near the positioning protrusions 2500 and 2600, respectively, so that the assembled inkjet cartridge IJ
C (Fig. 3), the three sides around it are parallel grooves 300.
At the extension point of the head tip region formed by a plurality of projections 2500.2, dust and ink are
It is located so that it does not reach 600. This parallel groove 3000 is formed. As can be seen in FIG. 5, the lid member 800 forms the outer wall of the inkjet cartridge IJC, and together with the ink tank forms a space in which the inkjet unit IJU is accommodated. In addition, in the ink supply member 600 in which the parallel groove 3001 is formed, the ink conduit 1600 that is continuous with the ink supply pipe 2200 described above is formed as a cantilever beam with the supply pipe 2200 side fixed, and the fixed side of the ink conduit and the ink Supply pipe 2
A sealing bottle 602 is inserted to ensure capillary action with 200. Note that 601 is a packing that seals the connection between the ink tank IT and the supply pipe 2200, and 700 is a filter provided at the tank side end of the supply pipe.

Since this ink supply member 600 is molded, it is inexpensive and has high positional accuracy.It not only eliminates the loss of precision in forming and manufacturing, but also has a cantilevered conduit 1600 that allows the conduit 1 to be used in mass production. The state in which the ink socket 600 is pressed against the ink receptacle 1500 can be stabilized. In this example, a more complete communication state can be reliably obtained by simply pouring the sealing adhesive from the ink supply member side under this pressure-contact state. Note that the ink supply member 600 is fixed to the support body 300 through the hole 1901 of the support body 300.
．． This can be easily done by projecting the backside bottle (not shown) of the ink supply member 600 to 1902 through the holes 1901 and 1902 of the support 300, and heat-sealing the protruding portion to the backside of the support 300. be exposed. Note that this slightly protruding area of the heat-sealed back surface is the ink tank I.
Since it is housed in a recess (not shown) in the side wall surface of the inkjet unit IJU mounting surface of the T, the positioning surface of the unit IJU can be accurately obtained.

(ii) Ink tank IT configuration description The ink tank is constructed by inserting the cartridge main body 1000, the ink absorber 900, and the ink absorber 900 from the side of the cartridge main body 1000 opposite to the unit IJU mounting surface. and a lid member 1100 for sealing.

Reference numeral 900 denotes an absorber for impregnating ink, and is disposed within the cartridge body 1000.

1 200 is a supply port for supplying ink to the unit IJU consisting of the above-mentioned parts 100 to 600, and is also used to supply ink from the supply port 1 200 in the process before placing the unit in the section 1010 of the cartridge body 1000. It is also an injection port for impregnating the absorber 900 with ink by injecting ink.

In this example, the parts that can supply ink are the atmosphere communication port and the supply port, but the rib 2300 in the main body 1000 is used to ensure good ink supply from the ink absorber.
and the partial ribs 2500 and 2400 of the lid member 1100.
Since the ink supply port 1 200 is formed continuously from the 4o1 side over the farthest corner area, relatively good and uniform ink supply to the absorber can be achieved from the supply port 1200 side. It is important that this is done. This method is extremely effective in practice. This rib l 0
00 has four ribs parallel to the carriage movement direction on the rear surface of the ink tank main body 1000 to prevent the absorber from coming into close contact with the rear surface. Further, the partial ribs 2400 and 2500 are similarly provided on the inner surface of the lid member 1100 on corresponding extensions to the rib 1000, but unlike the rib 1000, they are in a divided state and prevent air from entering. The existence space is increased compared to the former. Note that the partial ribs 2500 and 2400 are distributed over a surface that is less than half of the total area of the lid member 1000. These ribs allow the tank supply port 1200 of the ink absorber to
It was possible to more stably and reliably guide the ink in the region of the corner farthest from the supply port 1200 to the supply port 1200 side by capillary force. Reference numeral 1401 denotes an atmosphere ventilation port provided in the lid member to communicate the inside of the cartridge with the atmosphere. Reference numeral 1400 denotes a liquid-repellent material disposed inside the atmospheric transport port 140l, which prevents ink from leaking from the atmospheric transport port 1400.

The ink storage space of the ink tank IT mentioned above has a rectangular shape, and the long sides are on the sides, so the arrangement of the ribs described above is particularly effective. In the case of a case or a cube, cover member 1
By providing ribs throughout the ink absorber 900, the ink supply from the ink absorber 900 can be stabilized. A rectangular parallelepiped shape is suitable for storing as much ink as possible within a limited space, but in order to use the stored ink for recording without wasting it, as mentioned above, it is necessary to It is important to provide ribs that can perform the above-mentioned action on two adjacent surface areas. Furthermore, the inner surface ribs of the ink tank IT in this embodiment are arranged in a substantially uniform distribution in the thickness direction of the rectangular parallelepiped-shaped ink absorber. This configuration is important because it can equalize the atmospheric pressure distribution and almost eliminate the remaining amount of ink with respect to the ink consumption of the entire absorber. Furthermore, to explain the technical idea behind the arrangement of the ribs in detail, when an arc is drawn with the long side as the radius and centered on the projected position of the ink supply port l200 of the ink tank on the top surface of the quadrangle of the rectangular parallelepiped, It is important to arrange the ribs on the surface outside the arc so that the atmospheric pressure can be quickly applied to the absorbent body located outside the arc. In this case, the atmosphere communication port of the tank is not limited to this example, as long as it is at a position where the atmosphere can be introduced into the region where the ribs are provided.

In addition, in this embodiment, the inkjet cartridge I
The rear surface of the JC head is flattened to minimize the space required when incorporated into the device, and the structure maximizes the ink storage capacity, resulting in a more compact device. Not only that, but it also has an excellent structure that reduces the frequency of cartridge replacement. Then, by utilizing the rear part of the space for integrating the inkjet unit IJtJ, a protruding part for the air transport port 1401 is formed there, and the inside of this protruding part is hollowed out, and the above-mentioned absorption An atmospheric pressure supply space 1402 is formed over the entire thickness of the body 900. By configuring it in this way, we were able to provide an excellent cartridge that has not been seen before.
is a much larger space than the conventional one, and the atmospheric air passage port 1401 is located above, so even if the ink leaves the absorber due to some abnormality, this atmospheric pressure supply space 1402 will not displace the ink. can be temporarily retained and reliably collected by the absorber, making it possible to provide an excellent cartridge with no waste.

Further, the structure of the mounting surface of the unit IJU of the ink tank IT is shown in FIG. Assuming that a straight line L passes through approximately the center of the protruding opening of the orifice plate 400 and is parallel to the mounting reference plane of the bottom surface of the tank IT or the surface of the carriage, the line 2 that engages with the hole 312 of the support body 300
The two positioning protrusions 1012 are on this straight line L1. The height of this protrusion 1012 is slightly lower than the thickness of the support 300, and positions the support 300. In this drawing, the claw 2100 that engages with the 90" square engagement surface 4002 of the carriage positioning hook 4001 is located on the extension of the straight line 88 L +, and the positioning force on the carriage is applied to the straight line Ll. As will be explained later in FIG. Since they are equivalent, this is a valid configuration.

Further, a hole 19 for fixing the support body 300 to the side surface of the ink tank is provided.
Ink tank protrusions 18 corresponding to 00.2000 respectively
00.1801 is longer than the above-mentioned protrusion I012, and the part that protrudes through the support 300 is thermally fused to form the support 3.
This is for fixing 00' to its side. The above line L. A straight line perpendicular to and passing through this protrusion 1800 is Ls,
When the straight line passing through the protrusion 1801 is L, the approximate center of the supply port 1 200 is located above the straight line L, so
This is a preferable configuration because it works to stabilize the connection state between the mouth 1200 of the supply section and the supply pipe 2200, and reduces the load on the connection state even if a drop or impact occurs. Also, straight line L. ,L. do not match, and the presence of protrusions 1800 and 1801 around the protrusion 1012 on the discharge port side of the head IJH further produces a reinforcing effect in positioning the head IJH with respect to the tank. Note that the curve indicated by L4 is the outer wall position when the ink supply member 600 is attached. The protrusions 1800.1801 are the songs II L. , it provides sufficient strength and positional accuracy even for the weight of the distal end side configuration of the head TJH. In addition, 2700
is the tip flange of the ink tank IT, and is attached to the front plate 4 of the carriage.
This is provided in case of an abnormal situation where the ink tank is inserted into the 000 hole and the displacement of the ink tank becomes extremely poor.

2l01 is a retainer for the carriage, which is provided to a bar (not shown) of the carriage HC, and is a retainer for the cartridge I.
This is a protective member for maintaining the mounted state even if a force is applied in the upward direction that causes the JC to enter the lower part of the bar at the pivoted mounted position and unnecessarily disengage from the positioned position as will be described later.

The ink tank IT has a shape that surrounds the unit IJU except for the lower opening by covering it with the lid 800 after the unit IJU is installed, but the inkjet cartridge IJC has a lower opening for placing it on the carriage HC. Since it is close to the carriage HC, it forms a substantial four-sided surrounding space. Therefore, although the heat generated from the head IJH in this enclosed space is effective as a heat-retaining space, the temperature rises only slightly during long-term continuous use. For this reason, in this example, a slit 1700 with a width smaller than this space is provided on the upper surface of the cartridge IJC in order to aid the natural heat dissipation of the support, thereby preventing a rise in temperature and ensuring a uniform temperature distribution throughout the unit IJU. We were able to make the process unaffected by the environment.

When assembled as an inkjet cartridge IJC, ink is supplied from inside the cartridge into the supply tank 600 through the supply port 1200, the hole 320 provided in the support 300, and the introduction port provided on the inner back side of the supply tank 600. After passing through the interior, the ink flows into the common liquid chamber from the outlet through an appropriate supply pipe and the ink inlet 1500 of the top plate 400. A packing made of, for example, silicone rubber or butyl rubber is disposed at the above-mentioned connection portion for ink communication, and this seals the ink supply path to ensure an ink supply path.

In this embodiment, the top plate 1300 is made of a resin such as polysulfone, polyethersulfon, polyphenylene oxide, or polypropylene, which has excellent ink resistance, and is molded together with the orifice plate part 400 in a mold. It has been done.

As mentioned above, the integrally molded parts include the ink supply member 600,
Top plate and orifice plate integrated, ink tank body 10
00, it not only achieves a high level of assembly accuracy, but is also extremely effective in improving quality in mass production. Furthermore, since the number of parts can be reduced compared to the prior art, excellent desired characteristics can be reliably exhibited.

In addition, in the embodiment of the present invention, in the above-mentioned shape after assembly,
As shown in FIGS. 2 to 4, the ink supply member 6
00, the upper surface part 603 forms a slit S as shown in FIG.
A slit (not shown) similar to the slit S is formed between the lower lid 800 of the ink tank IT and the head side end 4011 of the thin plate member to which the lower lid 800 of the ink tank IT is bonded. These slits between the ink tank IT and the ink supply member 600 substantially act to further promote heat dissipation through the slit 1700, and even if there is unnecessary pressure applied to the tank IT, it is directly transferred to the supply member. In particular, this prevents the effects on the IJT of inkjet units.

In any case, the above-mentioned structure of this embodiment is a structure that has not been seen in the past, and each of them individually has an effective effect, and also in combination, each component has an organic structure. is bringing.

(iii) Description of attaching the inkjet cartridge IJC to the carriage C In FIG. 5, 5000 is a platen roller that guides the recording medium P from the bottom to the top of the page.

The carriage HC moves along the platen roller 3000, and has a front plate 40 located on the front side of the inkjet cartridge IJC on the front platen side of the carriage.
00 (thickness: 2 mm) and pads 2011 corresponding to the pads 201 of the wiring board 200 of the cartridge IJC} 4005, and a flexible sheet 4005 for generating an elastic force to press it against each pad 2011 from the back side. An electrical connection support plate 4003 holding a rubber pad sheet 4007 and an inkjet cartridge IJ
Positioning hook 400 for fixing C to the recording position
1 is provided. The front plate 4000 has two positioning projecting surfaces 4010 corresponding to the aforementioned positioning projections 2500 and 2600 of the cartridge support 300, respectively, and receives a vertical force toward these projecting surfaces 4010 after the cartridge is mounted. For this reason, the front plate should have a plurality of reinforcing ribs (not shown) on the platen roller side facing in the direction of the perpendicular force.

This rib is located at the front position L when the cartridge IJC is installed.
A head protection protrusion that protrudes slightly (approximately 0.1 mm) toward the platen roller is also formed.

The electrical connection support plate 4003 has a plurality of reinforcing ribs 4004 not in the direction of the ribs but in the vertical direction, and the proportion of lateral protrusion decreases from the platen side toward the hook 4001 side. This also serves the function of tilting the position when the cartridge is installed as shown in the figure.

In addition, in order to stabilize the electrical contact state, the support plate 4003 is used to position the hook side to apply force to the cartridge in the opposite direction to the direction in which the two positioning protruding surfaces 4010 act on the cartridge. It has two surfaces 4006 corresponding to the protruding surfaces 4010, which defines a pad contact area between them and uniquely defines the amount of deformation of the bottom of the rubber seat 4007 with a button corresponding to the button 2011. When the cartridge IJC is fixed at a recordable position, these positioning surfaces come into contact with the surface of the wiring board 300. In this example, the wiring board 300
Since the pads 201 are distributed symmetrically with respect to the aforementioned line L, the amount of deformation of each hole of the rubber seat 4007 is made uniform, and the contact pressure of the pads 2011 and 201 is made more stable. The distribution of pads 201 in this example is upward. There are two rows below and two rows vertically.

The hook 4001 has an elongated hole that engages with the fixed shaft 4009, and uses the movement space of the elongated hole to rotate counterclockwise from the position shown in the figure, and then moves to the left along the platen roller 5000. By moving, the inkjet cartridge IJC is positioned with respect to the carriage HC. Although this hook 4001 may be moved by any means, it is preferable to use a lever or the like. In any case, when the hook 4001 is rotated, the cartridge IJC moves toward the platen roller and the positioning protrusion 2500.2600
moves to a position where it can come into contact with the positioning surface 4010 of the front plate, and as the hook 4001 moves to the left, the 90" hook surface 4002 touches the 90" of the claw 2100 of the cartridge IJC.
Position the cartridge IJC while keeping it in close contact with the surface 25
Pads 00.4010 rotate in a horizontal plane around the contact area between pads 201 and 2011, and finally contact between pads 201 and 2011 begins.

When the hook 4001 is held in a predetermined position, that is, a fixed position, the pads 201 and 2011 are in complete contact with each other, the positioning surfaces 2500 and 4010 are in complete surface contact, and the 90-degree surface 4002 and the 90-degree surface of the claw are brought into contact with each other. The two-surface contact between the two surfaces and the surface contact between the wiring board 300 and the positioning surface 4006 are simultaneously formed, and the holding of the cartridge IJC in the carriage is completed.

(iv) General description of the main body of the apparatus FIG. 6 shows an inkjet recording apparatus I to which the present invention is applied.
In the general view of JRA, the carriage HC that engages with the spiral groove 5004 of the lead screw 5005, which rotates via the drive force transmission gears 5011 and 5009 in conjunction with the forward and reverse rotation of the drive motor 5013, is a pin (not shown). ) and is moved back and forth in the directions of arrows a and b. Reference numeral 5002 is a paper holding plate that holds the paper on the platen 5 in the carriage movement direction.
@5007 and 5008 that press against 000 are home position detection means for confirming the presence of the lever 5006 of the carriage in this area with a photo camera and switching the rotational direction of the motor 5013. 50l6 is a member that supports a cap member 5022 that caps the front surface of the recording head, and 5015 is a suction means that sucks the inside of this cap, and performs suction recovery of the recording head through an opening 5023 in the cap. 5017 is a cleaning blade, 5
Reference numeral 019 denotes a member that allows this blade to move in the front and back direction, and these are supported by a main body support plate 5018. Needless to say, the blade is not of this type, but a well-known cleaning blade can be applied to this example. Also, 5
012 is a lever for starting suction for arch recovery;
It moves with the movement of the cam 5020 that engages with the carriage, and the movement of the driving force from the drive motor is controlled by known transmission means such as clutch switching.

Catching, cleaning, and suction recovery are configured so that the desired processing can be performed at the corresponding positions by the action of the lead screw 5005 when the carriage comes to the home position side area. Any of these can be applied to this example as long as they are activated. Each of the configurations described above is an excellent invention whether viewed singly or in combination, and represents a preferable configuration example for the present invention.

In order to explain in detail the present invention technically related to the above-mentioned FIGS. 2 to 6, the following description will be made using FIGS. 1 and 7 and subsequent figures.

FIG. 1 is a schematic explanatory diagram showing the principle of liquid discharge in the apparatus of the present invention (this figure shows a cross section of one discharge orifice). A liquid 3 is supplied into the recording head l through means such as a supply tank (not shown), a supply pipe (not shown), or a filter (not shown).

Note that pressure P may be applied to the liquid by an appropriate pressurizing means such as a pump to such an extent that it cannot be discharged from the discharge orifice 2 by itself.

As shown in this figure, a heating element 4, which is a means for generating thermal energy, is installed in a heat acting part 5, which is a part where the generated thermal energy acts on the liquid 3. The heat acting portion 5 is a portion where thermal energy generated by the heating element 4 is applied to the liquid 3, and the liquid in the heat acting portion 5 undergoes a state change (liquid volume expansion, generation of bubbles, etc.).

As is clearer from FIG. 1, the essential feature of the present invention is that the liquid 3 flows in the direction in which the liquid 3 flows from the supply channel 6 into the heat effecting part 5, and flows out from the heat effect part 5 in the direction of the discharge orifice 2. The heating element installation surface and the inner surface of the discharge port coincide with each other, and the flow path extends symmetrically from the heat acting part 5 along the center line of the discharge port, and is throttled by the discharge port orifice. Due to these features, the intended object of the present invention is effectively achieved.

To explain this point in more detail, the heat acting portion 5 of the supply channel 6
It is an axis obtained by rotating the line segment XO to the left by an angle θ around the center line XO of the nearby part (parallel to the time when it flows from the supply channel 6 to the heat effecting part 5) point 0, and is discharged from the heat effecting part 5. The heat acting part 5, the supply flow path 6, and the discharge orifice 2 are arranged so that the heat acting part 5, the supply channel 6, and the discharge orifice 2 have an angle θ between them and the YO parallel to the direction of outflow from the orifice 2.

The above-mentioned angle θ can take various values other than the angle shown in the figure in designing the recording head.

However, when θ is between 0 and 90'', it is difficult to form supply channels, discharge orifices, etc., so normally 90'≦O≦1
The angle is preferably 80°, preferably 135°≦θ≦1
It is 77°.

On the other hand, regarding the discharge flow path 7, the discharge flow path 7 is composed of an orifice plate 9, a top plate lO having an ink passage groove, and a heater board 8.

The inner surface of the orifice coincides with the heating element installation surface and forms part of the discharge flow path. Furthermore, the orifice plate 9 and the top plate 1 are arranged so that they are axially symmetrical with respect to the center line OY of the discharge port.
A discharge flow path is formed by 0, and the width of the flow path is widened in the direction of the discharge port, so the outflow resistance is reduced.
Discharge efficiency is improved.

Further, the fact that the tip of the discharge port is constricted by the orifice plate 9 has the function of adjusting the discharge speed and discharge amount.

The axially symmetrical structure along the center line of the ejection port forms a meniscus with a negative direction vector relative to the ink ejection direction after the ink droplet is ejected, that is, in the process of defoaming the bubbles generated in the heat acting part. . The formation or vector of this meniscus is a factor that determines the ejection direction of the satellite droplet, and since the vector has a vector on the center line of the ejection port, it is possible to make the ejection direction of the main droplet and the satellite droplet the same, which makes it possible to make satellite printing easier. It is not possible to provide high-quality images.

The present invention provides excellent effects particularly in bubble jet recording heads and recording apparatuses among ink jet recording systems.

As for typical configurations and principles thereof, it is preferable to use the basic principles disclosed in, for example, US Pat. No. 4,723,129 and US Pat. No. 4,740,796. 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, it is necessary to arrange the liquid (ink) in accordance with the sheet and liquid path that hold it. As an electrothermal converter,
By applying at least one drive signal corresponding to recorded information and providing a rapid temperature rise above nucleate boiling, the electrothermal transducer generates thermal energy to cause film boiling on the thermally active surface of the recording head. As a result, bubbles in the liquid (ink) can be formed in one-to-one correspondence with this drive signal, which is effective. The growth and contraction of the bubble causes liquid (ink) to be ejected through the ejection opening to form at least one drop. It is more preferable to use this drive signal in a pulse form, since the growth and contraction of bubbles can be carried out immediately and appropriately, so that ejection of liquid (ink) with particularly excellent responsiveness can be achieved. As this pulse-shaped drive signal, those described in US Pat. No. 4,463,359 and US Pat. No. 4,345,262 are suitable. Incidentally, U.S. Patent No. 431 for the invention regarding the temperature increase rate of the heat acting surface
If the conditions described in specification No. 3124 are adopted,
Even better recording can be performed.

The configuration of the recording head includes, in addition to the combined configuration of ejection ports, liquid paths, and electrothermal converters (straight liquid flow path or right-angled liquid flow path) as disclosed in the above-mentioned specifications, a heat acting section. US Pat. No. 4,558,333 and US Pat. No. 4,459,600 disclose a configuration in which the
The present invention also includes a configuration using the specification of the above specification.

In addition, Japanese Patent Application Laid-Open No. 123670 of 1982 discloses a configuration in which a common slit is used as a discharge part for a plurality of electrothermal converters, and an open source patent publication for absorbing pressure waves of thermal energy is disclosed. The present invention is also effective as a configuration based on Japanese Patent Application Laid-Open No. 138461 of 1981, which discloses a configuration in which holes correspond to discharge portions.

Furthermore, as a full-line type recording head having a length corresponding to the width of the maximum recording medium that can be recorded by the recording apparatus, the length can be increased by combining multiple recording heads as disclosed in the above-mentioned specification. Either a configuration that satisfies the above requirements or a configuration as a single recording head formed integrally may be used, but the present invention can more effectively exhibit the above-mentioned effects.

In addition, a replaceable chip-type recording head that is attached to the device body enables electrical connection to the device body and ink supply from the device body, or a chip-type recording head that is installed integrally with the recording head itself. The present invention is also effective when a cartridge type recording head is used.

Further, it is preferable to add recovery means, preliminary auxiliary means, etc. for the recording head, which are provided as a configuration of the recording apparatus of the present invention, because the effects of the present invention can be further stabilized. Specifically, these include preheating means for the recording head using a caving means, a cleaning means, a pressurizing or suction means, an electrothermal transducer or another heating element, or a combination thereof. It is also effective to perform a preliminary ejection mode in which ejection is performed separately from printing in order to perform stable printing.

Furthermore, the recording mode of the recording device is not limited to a recording mode in which only the mainstream color such as black is used; the recording head may be configured integrally or in combination with a plurality of recording heads; The present invention is also extremely effective for devices equipped with at least one full color image.

〔Effect of the invention〕

As explained above, in the present invention, the direction in which the liquid flows from the supply channel into the heat effecting section is different from the direction in which the liquid flows out from the heat effecting section toward the discharge port, and at least one part of the heating element installation surface and the orifice plate The flow path spreads symmetrically from the heat-acting part along the center line of the discharge port and is narrowed by the discharge port orifice, resulting in high discharge efficiency.
It is possible to provide an inkjet recording head that can obtain high-quality recording without satellite printing.

Further, since the number of parts is small and the structure is extremely simple, it is possible to provide a high-density multi-orifice type device that is easy to manufacture and has excellent productivity during mass production.

[Brief explanation of drawings]

Figure 1 is an explanatory diagram for explaining the principle of the apparatus of the present invention, Figure 2 is an exploded perspective view of the cartridge of the present invention, Figure 3 is an assembled perspective view of Figure 2, and Figure 4 is an inkjet unit. FIG. 5 is a perspective view of the attachment part of the IJU, FIG. 5 is an explanatory diagram of attachment of the cartridge IJC to the device, and FIG. 6 is an external view of the device of the present invention. 1... Recording head 2... Discharge port (4l) 3... Liquid 4... Heating element (101) 5... Heat acting section 6... Supply channel 1 7... Discharge flow Route 8... Heater board (100) 9... Orifice plate (40)

Claims (1)

[Claims] (1) A discharge port for discharging liquid in a predetermined direction, a heating element, a heat acting part where the thermal energy generated from the heating element acts on the liquid, and supplying the liquid to the heat acting part. a recording head having a supply flow path for ejecting the liquid in a predetermined direction; a drive signal supply means for generating a drive signal for driving the heating element to eject the liquid in a predetermined direction; The direction in which the material flows into the heat acting section from the channel is different from the direction in which it flows out from the heat acting section toward the discharge port,
At least a portion of the orifice plate is in contact with the heating element installation surface, and a flow path extends symmetrically from the heat acting portion along the center line of the discharge port, and is narrowed by the discharge port orifice. Inkjet recording head.