JP2007296642A - Inkjet recording head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inkjet recording head and a recorder whereby the reliability is enhanced by eliminating defects at the printing time by effectively removing bubbles in a liquid chamber, and also an amount of deformation at the time of a temperature rise can be suppressed. <P>SOLUTION: In the inkjet recording head, a recording element substrate where a plurality of nozzles for ejecting a liquid and a plurality of recording elements which generate an ejection energy are arranged is disposed on a recording element substrate supporting plate. A channel for supplying the ink to the recording element substrate is prepared in the recording element substrate supporting plate H1207. A filter member H1601 which prevents mixing of foreign matter into the recording element substrate is inserted in a gap of the recording element substrate supporting plate comprised of two or more layers. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an ink jet recording apparatus that performs a recording operation by discharging a liquid such as ink, and an ink jet recording head used in the recording apparatus. The present invention can be applied to a general printing apparatus, a copying machine, a facsimile having a communication system, an apparatus such as a word processor having a printing unit, or a multifunction recording apparatus combining these apparatuses. In particular, the present invention is suitably applied to a recording apparatus that performs high-speed and high-quality printing.

  Conventionally, an inkjet recording apparatus is low in running cost, can be downsized, and can easily support color image recording using a plurality of colors of ink. Widely used and commercialized.

  On the other hand, as an energy generating element that generates energy for ejecting ink from the ejection port of the recording head, an element that uses an electromechanical transducer such as a piezo element, or an electromagnetic wave such as a laser emits heat to generate heat. There are those that discharge ink droplets by the action of, and those that heat a liquid by an electrothermal conversion element having a heating resistor.

  Among them, an inkjet recording system head that uses thermal energy to eject ink droplets can arrange discharge ports at high density, and therefore can perform high-resolution recording. Recording heads that use electrothermal transducers as energy generating elements are also available in smaller sizes, and are sufficient for the advantages of IC technology and micromachining technology that have made significant progress in technology and improved reliability in the recent semiconductor field. This is advantageous because it can be used in high density, easy to mount with high density, and inexpensive to manufacture.

  Recently, in order to perform higher-definition printing, a method of creating a nozzle for ejecting ink with high accuracy using a photolithographic technique has been used.

  In recent years, in order to realize recording of high-detail images at a higher speed, the printing width has become longer, and realization of a longer recording head is also desired in the future. Specifically, a head having a length of 4 inches to 13 inches or the like has been required.

As another conventional example, Patent Document 1 can be cited.
Japanese Patent Laid-Open No. 02-000525

Challenge (1)
As the head becomes longer and faster in this way, bubbles tend to remain in the flow path for supplying ink, the common liquid chamber, and the like, which tends to cause defects during printing.

  For this reason, conventionally, a control sequence has been adopted in which printing is performed after removing bubbles in the ink supply flow path and the common liquid chamber as much as possible.

  However, as shown in FIG. 12, if there are protrusions such as the filter member H1600 in the common liquid chamber H2000, the flow of ink is hindered and bubbles cannot be efficiently removed. It was. These methods require high power pumps and increase the waste of ink due to refreshing. Further, as a method of removing bubbles, there is a method of using deaerated ink from which gas dissolved in the ink is removed, but in order to maintain a long-term deaeration degree, a deaeration device is incorporated in the recording apparatus, or It was necessary to use expensive parts such as a metal material having low gas permeability for all parts from the ink tank to the supply path.

  In other words, the burden on the user has increased because of an increase in the cost of the recording apparatus main body and an increase in running cost.

Challenge (2)
Although the deformation due to heat increases as the inkjet head becomes longer, the bonding of different members causes warpage due to the difference in linear expansion coefficient when the temperature rises, leading to deterioration in the accuracy of ink droplet landing. It was. In particular, the resin material H1602 serving as the base material of the filter member H1600 has a relatively large linear expansion coefficient and needs to be firmly fixed with the adhesive H1604, and thus has a great influence on deformation.

Challenge (3)
In the case of a configuration using a plurality of support substrates on which the recording elements are mounted, the adhesive protrudes into the ink flow path, but the component is eluted into the ink, and the ink discharge performance may be deteriorated after long-term use. . In order to prevent this, it is necessary to select an adhesive, which tends to be difficult to develop, and affects the cost.

  An object of the present invention is to provide a head and a recording apparatus that are inexpensive and have high printing reliability in view of the above-described problems of the prior art.

In order to achieve the above object, the inkjet recording head of the present invention comprises:
It is characterized in that a filter member, which is a protrusion for the ink flow in the common liquid chamber for supplying ink to each recording element substrate, is built in the recording element substrate support plate.

  As described above, in the present invention, the filter member that has been conventionally projected into the common liquid chamber is built in the recording element substrate support plate, thereby smoothing the ink flow in the common liquid chamber, reducing the flow resistance, It becomes possible to eliminate the catch.

  Further, since the filter member made of a resin material having a large linear expansion coefficient is not fixed with an adhesive, deformation at the time of temperature rise can be minimized.

  Therefore, a large-scale pump and deaeration device that have been conventionally required are not required. In addition, wasteful ink consumption due to frequent use of ink refreshing can be reduced. Further, since the amount of deformation of the head due to the temperature rise can be suppressed to the minimum, it is possible to prevent the deterioration of printing.

  That is, it is possible to provide a recording head and a recording apparatus with high reliability at a low cost.

  Next, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 to FIG. 11 are explanatory diagrams for explaining each of a suitable recording head, driving circuit, and ink jet recording apparatus to which the present invention is applied or applied, and their respective relationships. Hereinafter, the entire configuration will be described with reference to these drawings while describing the configuration of each part.

(1) Description of Recording Head As shown in FIG. 1, the recording head H1000 is an ink jet recording head that performs recording by flying ink. The energy generating element that generates energy for ejecting ink from the ejection port of the recording head is one that uses an electromechanical transducer such as a piezo element. And the like that discharge ink droplets, or those that heat a liquid by an electrothermal conversion element having a heating resistor.

  The proposal in this case is useful for any type of drive system, but here, representatively, it generates heat energy to generate film boiling for ink in response to an electrical signal. A description will be given using a bubble jet (registered trademark) side shooter type recording head which performs recording using an electrothermal transducer.

  As shown in the exploded perspective view of FIG. 2, the recording head H1000 includes a recording element unit H1001 and an ink supply member H1500 of an ink supply unit H1002. Further, as shown in the exploded perspective view of FIG. 3, the recording element unit H1001 includes a recording element substrate H1100, a first support substrate H1200, a second support substrate H1208, an electric wiring substrate H1300, a third plate H1400, a filter. It consists of member H1600.

(1-1) Recording Element Unit FIG. 4A is a diagram illustrating the configuration of the recording element substrate H1100, and FIG. 4B is a cross-sectional view taken along line AA shown in FIG. The recording element substrate H1100 has a thin film formed of, for example, a Si substrate H1108 having a thickness of 0.5 to 1 mm. Further, an ink supply port H1101 composed of a long groove-like through-hole is formed as an ink flow path, and electrothermal conversion elements H1102 are arranged in a staggered pattern on each side of the ink supply port H1101, respectively. The electric wiring such as the element H1102 and Al is formed by a film forming technique. An electrode H1103 is provided to supply power to the electrical wiring. The ink supply port H1101 performs anisotropic etching using the crystal orientation of the Si substrate H1108. When the wafer surface has a crystal orientation of <100> and a thickness direction of <111>, the etching proceeds at an angle of about 54.7 degrees by anisotropic etching (KOH, TMAH, humanradine, etc.) . Using this method, etching is performed to a desired depth. A nozzle plate H1110 is provided on the Si substrate H1108, and an ink flow path H1104, a nozzle H1105, and a foaming chamber H1107 corresponding to the electrothermal conversion element H1102 are formed by a photolithography technique. The nozzle H1105 is provided so as to face the electrothermal conversion element H1102, and causes the ink supplied from the ink supply port H1101 to generate bubbles by the electrothermal conversion element H1102 to discharge the ink. .

  The first support substrate H1200 and the second support substrate H1208 are made of, for example, an alumina (Al2O3) material having a thickness of 0.5 to 10 mm. The material of the first support substrate H1200 and the second support substrate H1208 is not limited to alumina, and has a linear expansion coefficient equivalent to the linear expansion coefficient of the material of the recording element substrate H1100, and the recording element. The substrate H1100 may be made of a material having a thermal conductivity equal to or higher than that of the material. The material of the first support substrate H1200 and the second support substrate H1208 is, for example, silicon (Si), aluminum nitride (AlN), zirconia, silicon nitride (Si3N4), silicon carbide (SiC), molybdenum (Mo), tungsten. Any of (W) may be used. An ink supply port H1201 for supplying ink to the recording element substrate H1100 is formed in the first support substrate H1200 and the second support substrate H1208, and the ink supply port H1101 of the recording element substrate H1100 is the first support substrate H1100. This corresponds to the ink supply port H1201 of the plate H1200.

  FIG. 5A is a diagram illustrating the configuration of the first support substrate H1200, the second support substrate H1208, and the filter member H1600, and FIG. 5B is a cross-sectional view taken along the line AA ′ of FIG. is there.

  The filter H1601 in the filter member H1600 is provided for removing foreign matter in order to prevent the ink discharge nozzles on the recording element substrate from being clogged with foreign matter. As the material, a braided material of SUS fiber is used. The filter H1601 is joined to a mold member H1602 formed of polysulfone resin or the like by welding with ultrasonic waves and heat. H1603 is a packing made of an elastic body such as rubber.

  The first support substrate H1200 and the second support substrate H1208 are attached to each other with an adhesive H1209 so as to sandwich the filter member H1600.

  The recording element substrate H1100 is bonded and fixed to the first support substrate H1200 with high positional accuracy. The adhesive is desirably, for example, a material having a low viscosity, a thin adhesive layer formed on the contact surface, a relatively high hardness after curing, and ink resistance. For example, it is a thermosetting adhesive mainly composed of an epoxy resin, or an ultraviolet curing combined thermosetting adhesive, and the thickness of the adhesive layer is desirably 50 μm or less. The first support substrate H1200 has an X-direction reference H1204, a Y-direction reference H1205, and a Z-direction reference H1206, which are positioning references.

  As shown in FIG. 1, the recording element substrates H1100 are arranged in a zigzag pattern on the first support substrate H1200 to enable wide recording with the same color. For example, 13 recording element substrates H1100a, H1100b, H1100c, and H1100d with a nozzle group length of 1 inch + α are arranged in a staggered manner to enable 13-inch width recording.

  In addition, the end of each ejection element group of each recording element substrate is provided with a region (L) overlapping with the end of the nozzle group of the recording element board adjacent to the staggered pattern in the recording direction. Prevents gaps from being generated by printing. For example, overlapping regions H1109a and H1109b are provided in the nozzle group H1106a and the nozzle group H1106b.

  The electrical wiring substrate H1300 applies an electrical signal for ejecting ink to the recording element substrate H1100, has an opening for incorporating the recording element substrate H1100, and has a third surface on the back surface. The plate H1400 is bonded and fixed. The electric wiring board H1300 has an electrode terminal H1302 corresponding to the electrode H1103 of the recording element board H1100, and an external signal input terminal H1301 for receiving an electric signal from the recording apparatus main body located at the end of the wiring. Yes. The electrical wiring substrate H1300 and the recording element substrate H1100 are electrically connected. For example, the electrode H1103 of the recording element substrate H1100 and the electrode terminal H1302 of the electrical wiring substrate H1300 are connected to a gold wire H1303 (not shown). It is electrically connected by the wire bonding technique used. As a material of the electrical wiring board H1300, for example, a flexible wiring board having a two-layer structure is used, and a surface layer is covered with a polyimide film.

  The third plate H1400 is formed of, for example, a SUS plate having a thickness of 0.5 to 1 mm. Note that the material of the third plate is not limited to SUS, and may be made of a material having ink resistance and good flatness. The third plate H1400 has a recording element substrate H1100 bonded and fixed to the first support substrate H1200 and an opening for taking in the recording element substrate, and is bonded and fixed to the first support substrate.

  A groove formed by the opening H1402 of the third plate and the side surface of the recording element substrate H1100 is filled with the first sealant H1304, and the electrical mounting portion of the electrical wiring substrate H1300 is sealed. Further, the electrode H1103 of the recording element substrate is sealed with a second sealant H1305 to protect the electrical connection portion from corrosion by ink and external impact.

(1-2) Ink Supply Unit The ink supply member H1500 is made of, for example, resin molding or a ceramic material such as alumina or carbon graphite, and includes a common liquid chamber H1501 and a Z-direction reference surface H1502. The Z reference plane H1502 positions and fixes the recording element unit and serves as the Z reference for the recording head H1000.

(1-3) Coupling of Recording Element Unit and Ink Supply Unit As shown in FIG. 2 described above, the recording head H1000 is completed by coupling the recording element unit H1001 to the ink supply member H1500.

  The coupling is performed as follows.

  The opening of the ink supply member H1500 and the recording element unit H1001 are sealed with a third sealant H1503, and the common liquid chamber H1501 is sealed. Then, the Z reference H1502 of the recording element unit H1001 is positioned and fixed to the Z reference H1502 of the ink supply member by, for example, an adhesive. The third sealant H1503 is desirably a sealant that has ink resistance, is cured at room temperature, and can withstand the linear expansion difference between different materials.

  Further, the external signal input terminal H1301 portion of the recording element unit H1001 is positioned and fixed on the side surface of the ink supply member H1501, for example.

(2) Explanation of bubble removal in head and ink refreshing FIG. 10 is a diagram for explaining an example of a sequence for supplying ink to the head and refreshing it periodically.

  (2-1) First, as initial ink filling, both the valve A and the valve B are opened, and ink is filled into the common liquid chamber in the recording head by liquid feeding by the pump P100. At the same time, bubbles in the common liquid chamber are removed as much as possible by circulating ink in the common liquid chamber.

  (2-2) Next, the valve B is closed and the individual liquid chamber is filled with ink by pressurization with P100.

  (2-3) Further, in long-term use, the dissolved gas of the ink in the common liquid chamber is deposited to form bubbles, which are periodically excluded. This method is the same as (2-1), and the ink in the common liquid chamber is circulated and bubbles are allowed to flow together with the ink to be removed from the head.

(3) Description of Drive Circuit As shown in FIG. 1, in the recording head H1000 of the present application, four recording element substrates H1100 are accurately arranged on a chip plate H1200, and further four recording element substrates H1100 are electric wiring substrates H1300. It is wired with. FIG. 8 is a circuit diagram showing signal wiring between the four recording element substrates. In the figure, H1100a to H1100d each correspond to four printing element substrates, and each printing element substrate is composed of driving circuits for odd and even two nozzle rows shown in FIGS. HEATO, E and IDATAO, E are taken out separately for each element evenly and oddly, and are indicated by signal names HEAT1-8 and IDATA1-8 for each recording element substrate. Other signals are wired in common between the recording element substrates. LTCLK, DCLK, HEAT 1 to 8, and IDATA 1 to 8 are connected to an external signal input terminal H1301, and VH, GNDH, VDD, and GND that are power supply systems are connected to a power supply terminal H1302.

  FIG. 4 is a diagram showing the configuration of the recording element substrate H1100. On the both sides of the ink supply port H1101, odd-numbered and even-numbered nozzle rows are shifted by half the nozzle pitch. These two drive circuits are formed on the recording element substrate by a semiconductor process, and signals HEATO, E and IDATAO, E are wired independently by each drive circuit, but other signals (DCLK, LTCLK) and The power supplies (VDD, GND, VH, HGND) are common wirings in the recording element substrate. In both the odd and even nozzle rows, 640 nozzles are arranged at a pitch of 600 dpi and are shifted by a half pitch as described above, so that a 1200 dpi, 1280 nozzle is configured as the recording element substrate. Since the drive circuit of each nozzle row is exactly the same, the outline of the drive circuit will be described with reference to FIG. Each of the nozzles 640 is provided with discharge heaters H1102-1 to 1279, and by driving each discharge heater, the ink in the nozzles is foamed and ink droplets are discharged. The 20 discharge heaters are divided into 32 drive blocks, each of which is driven in a time division manner. The drive block is selected by signals BE0-31, and the 20 discharge heaters belonging to the drive block determine whether or not to discharge by turning ON / OFF the transistors E1006-1 to E1006-1.

  The drive of the recording head H1000 will be described with reference to the drive timing chart of FIG. 9 and FIG. The PRINT signal is a pulse signal that gives the timing for starting ejection of one column, and the operation of the drive circuit starts at the rise timing of the pulse. When the drive circuit starts operation, LTCLK is generated first, and several hundreds ps after that, the transfer clock DCLK is output for the transfer data, that is, 25 clocks. Transfer data is output to each signal of IDATA1 to 8 in synchronization with DCLK and serially transferred to a 25-bit shift register E1001. The data stored in the shift register E1001 is stored in the 25-bit latch E1002 at the timing of LTCLK output at the beginning of the next drive block. Therefore, the actual driving is performed according to the first transfer data at the timing when the next block is transferred. The data content transferred here is a total of 25 bits, ie, the drive block number BENB0-4 is 5 bits and the drive data of the electrothermal transducer H1102 driven in that block is 20 bits. The drive blocks BENB0-4 are decoded into BE0-31 by the 5 → 3 decoder E1003 and connected to the base electrodes of the transistors E1005-1-312. Therefore, only one of the 32 transistors E1005-1 to 32 is always driven, and the drive power supply (VH) is supplied only to one end of the electrothermal conversion element belonging to the designated block. . On the other hand, the other ends of the electrothermal transducers H1102-1 to 1279 are connected in parallel by 32 for each segment, and are connected to the collector electrodes of 20 transistors E1006-1 to 20, respectively. The driving of these transistors is controlled by the outputs of AND gates E1004-1 to 20 connected to the base electrode. A 20-bit drive data signal is connected to one input of the AND gate, and pulse signals HEAT1 to 8 for giving timing for actually driving the electrothermal transducer are connected to the other input. Therefore, the transistors E1006-1 to 20 are controlled by AND of the two signals, and as a result, the segment specified by the 20-bit drive data is driven at the pulse timing of HEAT1 to 8. . As described above, when the PRINT signal is activated, the drive circuit starts to operate, the first block is driven first, sequentially becomes 1, 2,..., And finally the 31st block is completely driven. The ejection of all nozzles on the printing element substrate is controlled.

(4) Description of Inkjet Recording Apparatus As shown in FIG. 5, the inkjet recording apparatus M4000 of the present invention includes, for example, recording heads for six colors corresponding to photographic image quality recording. The recording head H1000Bk is a recording head for black ink, the recording head H1000C is for cyan ink, the recording head H1000M is for magenta ink, the recording head H1000Y is for yellow ink, the recording head H1000LC is for light cyan ink, and the recording head H1000LM is light. For magenta ink. These recording heads H1000 are fixedly supported by positioning means and electrical contacts M4002 of a carriage M4001 mounted on the recording apparatus main body M4000.

  These recording heads are controlled by the drive circuit described above to perform recording on a recording medium. 5 is a full-line type in which the recording head has nozzles corresponding to the width of the recording medium, the recording head is fixed, and recording is performed by scanning the recording medium in the direction of the arrow.

  On the other hand, the recording apparatus of FIG. 10 is a serial drive type recording apparatus in which the recording head performs recording while reciprocating in the main scanning direction (carriage movement direction).

FIG. 2 is an external perspective view of the recording head of the present invention. FIG. 3 is an exploded perspective view of the recording head of the present invention. FIG. 3 is an exploded perspective view of a recording element unit. FIG. 4A is a perspective view illustrating a recording element substrate, and FIG. The cross-sectional schematic diagram of this invention. FIG. 6 illustrates an ink jet recording apparatus (full line method). The figure explaining the drive circuit of an odd number nozzle row. The figure explaining the drive circuit of an even number nozzle row. FIG. 4 is a diagram for explaining signal wiring between four recording element substrates. The drive timing chart figure. The cross-sectional schematic diagram of this invention. The cross-sectional schematic diagram of this invention.

Explanation of symbols

H1000 recording head H1001 recording element unit H1002 ink supply unit H1100 recording element substrate H1101 ink supply port H1102 electrothermal conversion element H1103 electrode H1104 ink flow path H1105 nozzle H1106 nozzle group H1107 foaming chamber H1108 Si substrate H1110 nozzle plate H1200 support substrate H1201 ink supply Port H1204 X direction reference H1205 Y direction reference H1206 Z direction reference H1207 First support substrate H1208 Second support substrate H1300 Electrical wiring substrate H1301 External signal input terminal H1302 Electrode terminal H1303 Gold wire (not shown)
H1304 First sealant H1305 Second sealant H1400 Second plate H1500 Ink supply member H1501 Liquid chamber (not shown)
H1502 Z reference plane H1503 Third sealant (not shown)
H1504 Ink supply port (not shown)
H1600 Filter member H1601 Filter H1602 Mold member H1603 Packing H1604 Adhesive H1800 Ink tank H1802 Tube H1900 PCB
H1901 External signal input terminal M4000 Inkjet recording apparatus M4001 Carriage M4002 Electrical contact E1001 Shift register E1002 25-bit latch E1003 Decoder E1004 AND gate E1005 Transistor E1006 Transistor K1000 Recording medium

Claims (3)

A recording element substrate in which a plurality of nozzles for ejecting liquid and a plurality of recording elements for generating ejection energy are arranged is arranged on a support plate formed by bonding two or more layers of plates with an adhesive, and the recording element substrate Is provided with a supply port for supplying ink from the surface opposite to the recording element surface, and the support plate is provided with a flow path for supplying ink to the recording element substrate.
An ink jet recording head comprising a filter member for preventing foreign matter from entering a recording element substrate in a form of being sandwiched between support plates.   The inkjet recording head according to claim 1, wherein the filter member is not restrained by an adhesive as a method of fixing the filter member in the support plate.   3. The ink jet recording head according to claim 2, wherein a packing made of a rubber flexible material is inserted into a joint surface between the filter member and the support plate.

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