JPH06286127A - Ink jet recording head and ink jet recorder equipped therewith - Google Patents

Abstract

PURPOSE:To obtain an excellent image recording by a method wherein a distance between a discharge opening-formed face and a medium to be recorded can be set short. CONSTITUTION:A part of an ink tank 6 at which a driving element 3 is provided, is tapered in a shape. Thereby, the driving element 3 is provided on an opposed side in a discharge direction of a liquid drop (an ink drop) 9 to a discharge opening-formed face 13. Then, a distance between the discharge opening-formed face 13 and recording paper 7 can be shortened. Consequently, the driving element 3 and silicone resin 12 sealing the driving element 3 do not rub the recording paper 7 and an excellent image can be formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording head for ejecting ink from an ejection port to form ink droplets, and more particularly, an ink jet recording head provided with a drive element for ejecting ink on an external wiring portion. And an inkjet recording apparatus including the inkjet recording head.

[0002]

2. Description of the Related Art With regard to an ink jet recording head of this type, for example, an ink jet recording method described in Japanese Patent Laid-Open No. 54-51837 discloses that a thermal energy is applied to a liquid (ink) so that a driving force for ejecting droplets can be obtained. In terms of obtaining, it has a feature different from other ink jet recording methods.

That is, in the recording method disclosed in the above publication, the liquid which has been subjected to the action of thermal energy is overheated to generate bubbles, and the action force based on the generation of the bubbles causes the ejection port at the tip of the recording head portion. It is characterized in that droplets are formed from the droplets, and the droplets adhere to a recording medium such as recording paper to record an image.

In the ink jet recording head applied to this recording method, generally, an ejection port provided for ejecting a liquid and thermal energy for communicating with the ejection port and ejecting a droplet are applied to the liquid. A liquid discharge part having a liquid flow path having a heat acting part, which is a part acting, as a part of the constitution, and a heat converter (heat generating part) being means for generating heat energy.
, A heating resistance layer, an upper protection layer for protecting it from ink, and a lower layer for storing heat.

Such an ink jet recording head is
Since the heating resistance layer and the upper protective layer are formed by the thin film process, the cost for the thin film portion is high. In view of this, as disclosed in Japanese Patent Laid-Open No. 60-262657, it has been proposed to separate the discharge part and the external wiring part (lead electrode part).

As one embodiment of the above, Japanese Patent Laid-Open No. 63-5
In Japanese Patent No. 01415, an ejection element and an external wiring portion (external electrode portion) such as TAB are electrically connected by a beam lead, and the external wiring portion is connected to a flexible circuit on a carriage. An inkjet recording head having a structure connected to an external drive circuit has been proposed.

By the way, in recent years, there has been a demand for higher density of the ejection ports, and it is necessary to drive at a high frequency or print with the same print width in order to prevent the printing speed from decreasing. In order to print with the same print width at high density, the number of ejection openings naturally increases.

In the embodiment described in the above-mentioned Japanese Patent Laid-Open No. 63-501415, the external wiring portion is electrically connected by pressure welding to a flexible circuit which is electrically connected to the main body circuit on the carriage. Due to the increase in the number of times, the pressure installation was not successful and a connection failure often occurred.

As a means for eliminating this contact failure, FIG.
4 and FIG. 15, the driving element 3X is arranged on the external wiring board 2X as an external wiring section, the ejection element and the driving element 3X on the external wiring board 2X are electrically connected by the beam lead, and There is one in which the wiring board 2X is electrically connected by pressure contact to a flexible circuit X5 that is electrically connected to the main body circuit. The drive element 3X is composed of a shift register and a driver element, and is an element for generating drive signals to the plurality of heat generating portions by inputting a print signal. In this way, the number of electric wirings up to the drive element 3X is the same as the conventional one, but the number of connections between the external wiring board 2X and the flexible wiring board 5X electrically connected to the main circuit, that is, the number of pressure contact portions is reduced. That is, when the drive element is mounted on the head, the number of wirings between the head and the drive element is the same as that of the heat generating part, but the print signal sent to the drive element may be several print signal lines. Since the number of print signal lines between the two may be small, the number of press contact portions may be small.

Therefore, the external wiring board 2X and the flexible wiring board 5X were pressed well and there was no defective connection. In this inkjet recording head, a heater board 1X, which is a part of the head portion, and an ink tank 6X are integrated, and droplets are ejected from an ejection port 10X toward a recording paper 7X held by a platen 8X. An image is formed on the recording paper 7X by ejecting 9X. The external wiring board 2X is connected to the flexible wiring board 5X via the pressure contact portion 4X.
Electrically connected to. Reference numeral 13X indicates a discharge port forming surface formed on the orifice plate 11X.

[0011]

However, as shown in FIG.
As shown in, the distance H between the ejection port forming surface 13X and the recording paper 7X must be lengthened depending on the place where the drive element 3X is arranged, which causes printing failure. More specifically, if the ejected droplets (ink droplets) 9X reach the recording paper 7X early, printing defects due to deviation of the landing point due to variations in the ejection direction or the like are small. Therefore, the shorter the distance between the ejection port forming surface 13X and the recording paper 7X, the better. However, in the ink jet recording head of the type in which the discharge direction is perpendicular to the heater board (substrate) 1X provided with the heat generating portion, if the drive element 3X is arranged on the same plane as the discharge port element, Since the drive element 3X and the silicone resin 12X that seals the drive element 3X hit the recording paper 7X and are inconvenient,
It was difficult to obtain good image recording because the discharge port forming surface 13X had to be separated from the recording paper 7X.

The present invention has been made in view of the above problems of the prior art. Ink jet recording in which the distance between the ejection port forming surface and the recording medium can be set short, and as a result, good recording can be obtained. An object of the present invention is to provide a head and an inkjet recording apparatus including the inkjet recording head.

[0013]

SUMMARY OF THE INVENTION To achieve the above object, the present invention comprises an ejection port forming surface on which ejection ports for ejecting ink are formed and a substrate, and the ink is perpendicular to the substrate. A discharge element for discharging in a direction, and an external wiring part for applying an electric signal to the discharge element, and a drive element of the discharge element is arranged on the external wiring part. In an ink jet recording head in which a portion and the drive element are sequentially electrically connected, the drive element is provided on the side opposite to the ejection direction with respect to the ejection port forming surface of the ejection element. And

The ejection element is for ejecting ink by utilizing thermal energy, and is provided with an electrothermal converter for generating the thermal energy.

Further, the ink jet recording apparatus of the present invention comprises a conveying means for the recording medium, and an ink jet recording head of the present invention for ejecting ink toward the recording medium for recording. The recording medium is moved relative to the inkjet recording head, and ink is ejected from the inkjet recording head to record an image on the recording medium.

[0016]

In the present invention configured as described above, since the drive element is located on the side opposite to the ejection direction with respect to the ejection port forming surface, the drive element does not interfere with the recording medium and the ejection port forming surface is formed. The distance between the recording medium and the recording medium can be shortened, and good image recording can be obtained.

[0017]

Embodiments of the present invention will now be described with reference to the drawings.

First, the overall structure of the ink jet recording apparatus will be described with reference to FIG.

In the ink jet recording apparatus of this embodiment, a carriage 20 on which an ink jet recording head 14 to be described later is mounted is connected to a part of a drive belt 27 which transmits a driving force of a drive motor 28 and is arranged in parallel with each other. It is slidably attached to the two guide shafts 29, 30 provided. Due to the driving force of the drive motor 28, the inkjet recording head 14 is placed on the platen 8 arranged so as to face the ejection port forming surface (not shown) of the inkjet recording head 14, and a medium feeding device (not shown) ( The recording medium (not shown) as a recording medium fed from the conveying means reciprocates over the entire width to record an image on the recording medium.

Further, in the ink jet recording apparatus of this embodiment, the ink jet recording head 14 is moved to the position (guide shaft 29 in the figure) during the head recovering operation outside the range of the reciprocating movement of the ink jet recording head 14 in the recording operation. Of the inkjet recording head 14 is driven by the driving force of the cleaning motor 25 via the transmission mechanism 22 so as to face the ejection port forming surface of the inkjet recording head 14. A head recovery device 24 having a cap 21 for capping the ejection port forming surface is provided.

In the head recovery device 24, during the head recovery operation, in connection with the capping of the ejection port forming surface of the inkjet recording head 14 by the cap 21, ink is sucked by a recovery system pump (not shown) or the inkjet recording head is used. Ink is pressure-fed by an appropriate pressurizing means provided in the ink supply path to the ink supply head 14, and ink is forcibly discharged from the ejection port to perform head recovery operation such as removing thickened ink in the ejection port. By this head recovery process, the waste ink discharged from each ejection port of the inkjet recording head 14 is discharged and stored in the waste ink tank 31 as a storage member.

Further, on the side surface of the head recovery device 24,
A blade 23 formed of silicon rubber as a wiping member is held in a cantilever form by a blade holding member 26, and is operated by a cleaning motor 25 and a transmission mechanism like the head recovery device 24 to form an ejection port of the inkjet recording head 14. Engagement with the surface is possible. As a result, after the head recovery operation using the head recovery device 24, the blade 23 is projected into the moving path of the inkjet recording head 14, and the ejection opening forming surface of the inkjet recording head 14 is accompanied by the moving operation of the inkjet recording head 14. Wipe off condensation, wetness, dust, etc.

The ink jet recording head will be described below.

As shown in FIG. 2, in the ink jet recording head 14, an electric voltage is supplied to generate thermal energy for ejecting the recording liquid from a plurality of ejection ports 10 arranged in a row. The heat conversion body 15 is provided for each liquid path. Then, by applying a drive signal, thermal energy is generated in the electrothermal converter 15 to cause film boiling and form bubbles in the ink liquid path. Then, ink droplets are ejected from the ejection port 10 by the growth of the bubbles. The electrothermal converter 15 is provided on the heater board 1, and the discharge port 10 is formed on the orifice plate 11. Reference numeral 13 is the orifice plate 11.
The discharge port forming surface formed in FIG.

(First Embodiment) FIG. 3 is a side view of the first embodiment of the ink jet recording head of the present invention, and FIG.
FIG. 3 is a view seen from the side of the ejection port forming surface of the inkjet recording head of FIG.

Reference numeral 1 denotes a heater board having a heating resistor (electrothermal converter) formed on a silicon substrate (not shown). The heater board 1 has a plurality of ejection ports 10 for ejecting ink. Orifice plate 1 with open
1 is provided. The heater board 1 and the orifice plate 11 constitute a discharge element. Reference numeral 2 is an external wiring board as an external wiring section. The external wiring board 2 is composed of a shift register and a driver element, and generates a drive signal to a plurality of heating resistors (not shown) by inputting a print signal. Drive element 3 for The external wiring board 2 is electrically connected to the flexible wiring board 5 via the press contact portion 4, and the flexible wiring board 5 is connected to the main circuit (carriage 20, see FIG. 1). Reference numeral 6 indicates an ink tank attached to the heater board 1, reference numeral 7 is a recording paper as a recording medium, which is conveyed in the arrow Z direction, and reference numeral 8 is a platen which holds the recording paper 7.

The portion of the ink tank 6 where the drive element 3 is provided has a tapered shape, whereby the drive element 3 is located on the opposite side of the ejection port forming surface 13 from the ejection direction of the droplet 9. To position.

A specific method of manufacturing the ink jet recording head will be described below.

FIG. 5 is an enlarged view of portion A of FIG. 4, FIG. 6 is a sectional view taken along line XX of FIG. 5, FIG. 7 is an enlarged view of portion B of FIG. 4, and FIG. 8 is line YY of FIG. A sectional view and FIG. 9 are enlarged views of a portion C in FIG.

As shown in FIGS. 5 and 6, first, the heating resistance layer 37 and the electrode layer 38 are formed on the silicon substrate 45,
The heat generating portion (electrothermal converter) 35 is created by the photolithography technique. Next, a protective layer 36 is formed on the heat generating portion 35,
A hole 34 is formed in the portion to be electrically connected by the photolithography technique. In this embodiment, a metal such as gold is formed to electrically connect to the external wiring portion by the lead beam method. That is, the electrode pad (metal pad) 16 is formed at the portion electrically connected to the beam lead 17 by the photolithography technique.
In this way, the heater board 1 is completed. And
The orifice plate 11 formed by electroforming is attached to the heater board 1 to complete the discharge element.

As shown in FIGS. 7 and 8, the external wiring substrate 2 has a copper wiring 19 formed on a polyimide film, and the beam lead 17 is connected to the copper wiring 19 (hereinafter referred to as TAB). On this TAB, drive circuit,
The drive element 3 in which the shift register circuit is formed is die-bonded, and the drive element electrode pad 39 on the output side of the drive element 3 is connected to the copper wiring 19 on the TAB by the wire 18 by the wire bonding method. Reference numeral 40 is a copper wiring protective film 40 that protects the copper wiring 19. Further, in order to protect the drive element 3 from ink and humidity, the drive element 3 is sealed with a silicone resin 12 (see FIGS. 3 and 4) or the like.

Next, the external wiring board 2 thus created
Is bonded between the beam lead 17 and the electrode pad (metal pad) 16 of the heater board 1 by a thermocompression bonding method. The drive element electrode pad 39 on the input side of the drive element 3 is electrically connected to the copper wiring 41, and a press contact pad portion 42 is formed on the copper wiring 41. Finally, the ink tank 6 (see FIGS. 3 and 4)
Paste it on. Here, in the ink tank 6, as shown in FIG. 3, the portion of the external wiring substrate 2 where the drive element 3 is provided is tapered, and the drive element 3 is arranged on the opposite side of the ejection port forming surface 13 in the ejection direction. It is structured to In this way, an inkjet head with an ink tank (ink cartridge) is completed.

As shown in FIGS. 8 and 9, when the ink cartridge is mounted on the carriage 20 (see FIG. 1) on the main body, the external wiring board 2 has the pressure contact pad portion 42 and the flexible wiring board pressure contact pad portion 43. By pressure contacting with, the flexible circuit 5 for electrical connection with the main body is electrically connected. The pressure contact pad portion 42 and the flexible wiring board pressure contact pad portion 43 form the pressure contact portion 4.

As shown in FIGS. 3 and 4, the driving element 3 and the silicone resin 12 for sealing the driving element 3 are not on the same surface as the ejection port forming surface 13, but the ejection direction of the droplet (ink droplet) 9. The silicon resin 12 for sealing the drive element 3 and the drive element 13 is retracted to the side opposite to the recording paper 7
In addition, the distance between the ejection port forming surface 13 and the recording paper 7 can be shortened, and good image recording can be performed.

(Second Embodiment) FIG. 10 is a side view of a second embodiment of the ink jet recording head of the present invention, and FIG. 11 is a view seen from the ejection port forming surface side of the ink jet recording head of FIG. .

As shown in FIGS. 10 and 11, in this embodiment, the lower portion of the ink tank 6a in which the driving element 3a is provided is a stepped portion, and the driving element 3a and the driving element 3a are sealed. The silicone resin 12a is provided in the concave portion of the step portion, and is similar to the first embodiment in the discharge port forming surface 13a.
Is not on the same surface, and is retracted to the side opposite to the ejection direction of the droplet (ink droplet) 9a. As a result, the distance between the ejection port forming surface 13a and the recording paper 7a can be shortened,
Good image recording is possible. The other structure is the same as that of the first embodiment.

(Third Embodiment) FIG. 12 is a side view of a third embodiment of the ink jet recording head of the present invention, and FIG. 13 is a view seen from the ejection port forming surface side of the ink jet recording head of FIG. .

As shown in FIGS. 12 and 13, in this embodiment, the drive element 3b is provided below the ink tank 6b, and the drive element 3b and the drive element 3b are sealed as in the first embodiment. The silicone resin 12b to be applied is the discharge port forming surface 1
Since it is not on the same surface as 3b and is arranged below the ink tank 6b, the discharge port forming surface 13b and the recording paper 7b are not formed.
The distance between and can be shortened, and good image recording is possible. The other structure is the same as that of the first embodiment.

Although TAB is used in each of the above embodiments, other mounting methods may be adopted. Although the lead beam is used for the electrical connection between the ejection element and the external wiring portion, wire bonding may be used. Furthermore, although wire bonding is used for electrical connection between the drive element and the external wiring portion, a lead beam method may be used. In this case, the driving element does not interfere with shortening the distance between the recording paper and the ink cartridge, but the resin sealing of the driving element interferes with the driving element, and unless the shape of this embodiment is adopted, it is preferable. Image recording cannot be obtained.

The present invention brings excellent effects particularly in a recording head and a recording device of the type which ejects ink by utilizing thermal energy, which is proposed by Canon Inc. among ink jet recording systems.

With regard to its typical structure and principle, it is preferable to use the basic principle disclosed in, for example, US Pat. Nos. 4,723,129 and 4,740,796. This method is applicable to both so-called on-demand type and continuous type, but in particular,
In the case of the on-demand type, the electrothermal converter arranged corresponding to the sheet or liquid path where the liquid (ink) is held corresponds to the recorded information and the temperature rises rapidly beyond the nucleate boiling. By applying at least one drive signal that gives a heat energy to the electrothermal converter, the film is boiled on the heat-acting surface of the recording head, and as a result, the liquid (ink It is effective because bubbles can be formed inside. 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 the driving signal into a pulse shape because bubbles can be grown and contracted immediately and appropriately, and thus a liquid (ink) with excellent responsiveness can be ejected. As the pulse-shaped drive signal, those described in US Pat. Nos. 4,463,359 and 4,345,262 are suitable. In addition,
US Pat. No. 4, of the invention relating to the rate of temperature rise of the heat acting surface,
If the conditions described in the specification of 313,124 are adopted,
Further excellent recording can be performed.

As the constitution of the recording head, in addition to the combination constitution of the ejection port, the liquid passage, and the electrothermal converter (the straight liquid passage or the right-angled liquid passage) as disclosed in the above-mentioned respective specifications. U.S. Pat.No. 4,558,333, U.S. Pat.
The structure using the specification of No. 9,600 is also included in the present invention. In addition, for a plurality of electrothermal converters, JP-A-123670 discloses a configuration in which a common slit serves as a discharge portion of the electrothermal converters and an opening for absorbing a pressure wave of thermal energy. Japanese Patent Application Laid-Open No. Sho-Ai discloses a structure corresponding to a discharge unit
The present invention is also effective as a configuration based on the '138461 publication.

Further, as a full line type recording head having a length corresponding to the width of the maximum recording medium which can be recorded by the recording device, a combination of a plurality of recording heads as disclosed in the above-mentioned specification is used. The present invention can exert the above-mentioned effects more effectively, although it may have a configuration satisfying the length or a configuration as one recording head integrally formed.

In addition, by being attached to 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 that is specially provided is used.

Further, it is preferable to add recovery means for the recording head, preliminary auxiliary means, etc., 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. . Specific examples thereof include capping means, cleaning means, pressurization or suction means, an electrothermal converter or a heating element other than this, a preheating means for the recording head, and a recording head for the recording head. It is also effective to perform a preliminary ejection mode in which another ejection is performed for stable recording.

Further, the recording mode of the recording apparatus is not limited to the recording mode of only the mainstream color such as black, but the recording head may be integrally formed or a plurality of combinations may be used. The present invention is also extremely effective for an apparatus provided with at least one of full color 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 below, and is softened or liquid at room temperature, or the ink itself is 30 in the above ink jet. It is common to adjust the temperature within a range of ℃ to 70 ℃ to control the temperature of the ink so that the viscosity of the ink is within the stable ejection range. Good. In addition, it is possible to prevent the temperature rise due to thermal energy from being positively used as energy for changing the state of the ink from a solid state to a liquid state, or
Whether or not ink that solidifies in a standing state is used for the purpose of preventing evaporation of the ink, and in any case, the ink liquefies by being applied according to the recording signal of thermal energy and is ejected as an ink liquid or reaches a recording medium. The use of inks that have the property of only liquefying by thermal energy, such as those that have already begun to solidify at this point, is also applicable to the present invention. In such a case, the ink, as described in JP-A-54-56847 or JP-A-60-71260, in a state of being held as a liquid or a solid in the recesses or through holes of the porous sheet, It may be configured to face the electrothermal converter. In the present invention, the most effective one for each of the above-mentioned inks is to execute the above-mentioned film boiling method.

[0048]

Since the present invention is configured as described above, the driving element does not interfere with the recording medium, and the distance between the ejection port forming surface and the recording medium can be shortened. There is an effect that good image recording can be obtained and the manufacturing yield is improved.

In particular, in an ink jet recording apparatus in which this high-density, multi-nozzle type ink jet recording head is mounted on a scanned carriage, the ink cartridge and the carriage can be reliably connected to obtain a better image recording. To be

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of an inkjet recording apparatus.

FIG. 2 is a schematic perspective view of an inkjet recording head.

FIG. 3 is a side view of the first embodiment of the inkjet recording head of the present invention.

FIG. 4 is a diagram viewed from the ejection port forming surface side of the inkjet recording head of FIG.

5 is an enlarged view of part A in FIG. 4. FIG.

6 is a cross-sectional view taken along line XX of FIG.

FIG. 7 is an enlarged view of part B in FIG.

8 is a cross-sectional view taken along line YY of FIG.

9 is an enlarged view of a C portion of FIG.

FIG. 10 is a side view of a second embodiment of the inkjet recording head of the present invention.

FIG. 11 is a diagram viewed from the ejection port surface formation side of the inkjet recording head of FIG.

FIG. 12 is a side view of a third embodiment of the inkjet recording head of the present invention.

13 is a diagram viewed from the ejection port forming surface side of the inkjet recording head of FIG.

FIG. 14 is a side view of a conventional inkjet recording head.

15 is a diagram viewed from the ejection port forming surface side of the inkjet recording head of FIG.

[Explanation of symbols]

 1, 1a, 1b Heater board 2, 2a, 2b External wiring board (external wiring part) 3, 3a, 3b Driving element 4, 4a, 4b Pressure contact part 5, 5a, 5b Flexible wiring board 6, 6a, 6b Ink tank 7 , 7a, 7b Recording paper (recording medium) 8, 8a, 8b Platen 9, 9a, 9b Droplet 10, 10a, 10b Discharge port 11, 11a, 11b Orifice plate 12, 12a, 12b Silicon resin 13, 13a, 13b Discharge port forming surface 14 Ink jet recording head 15 Electrothermal converter 16, 16a, 16b Electrode pad 17, 17a, 17b Beam lead 18, 18a, 18b Wire 19, 19a, 19b Copper wiring 20 Carriage 21 Cap 22 Transmission mechanism 23 Blade 24 Head Recovery Device 25 Cleaning Motor 26 Breaker Holding member 27 Drive belt 28 Drive motor 29, 30 Guide shaft 31 Waste ink tank 32 Common electrode 33 Individual electrode 34 Hole 35 Heat generating part 36 Protective layer 37 Heat generating resistance layer 38 Electrode layer 39 Drive element electrode pad 40 Copper wiring protective film 41 Copper Wiring 42 Pressure contact pad 43 Flexible wiring board Pressure contact pad 44 Copper wiring protection film 45 Silicon substrate

Claims (3)

[Claims] 1. An ejection element comprising an ejection port forming surface on which ejection ports for ejecting ink are formed and a substrate, wherein ink is ejected in a direction perpendicular to the substrate, and an electric signal is applied to the ejection element. An inkjet having an external wiring part for applying a voltage, the drive element of the ejection element is disposed on the external wiring part, and the ejection element, the external wiring part, and the drive element are sequentially electrically connected. In the recording head, the inkjet recording head is characterized in that the drive element is provided on the side opposite to the ejection direction with respect to the ejection port forming surface of the ejection element. 2. The ink jet recording head according to claim 1, wherein the ejection element ejects ink by utilizing thermal energy, and includes an electrothermal converter for generating the thermal energy. . 3. The inkjet recording head according to claim 1, wherein the recording medium is transported by the inkjet recording head, and the inkjet recording head is configured to perform recording by ejecting ink toward the recording medium. An inkjet recording apparatus for recording an image on the recording medium by ejecting ink from the inkjet recording head while moving the recording medium relative to the inkjet recording head.