JP2009006560A - Inkjet recording head and recording apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the frequency of changing a head and to acquire a good picture by solving the problem that the head is required for changing even when non-discharging occurs in several nozzles because the occurrence of non-discharging is fatal in a one-pass print using a full multiple-type long recording head. <P>SOLUTION: In the full multiple-type long ink-jet head, a nozzle row for non-discharging complement is installed in each chip. The nozzle rows for complementing are arranged by half-pitch staggering against the dot rows of pixels, and further the nozzles are arranged by double-pitch of pixel pitch. <P>COPYRIGHT: (C)2009,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. In particular, the present invention relates to a printing method and a printing apparatus using a multi-nozzle inkjet recording head in which ink discharge ports are arranged in an integrated arrangement. 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.

  In addition, recently, in order to perform higher-definition printing, a method of creating a nozzle for ejecting ink with high accuracy using photolithography technology has been used, and the recording head has a higher density and a longer length. Things can be made. In order to realize high-definition image recording at a higher speed, technological development of a system that forms an image by performing a relative scan of a recording head and a recording medium is being advanced.

  In an inkjet, a non-ejection situation may occur accidentally during inspection or during a use period due to dust mixed during manufacture, nozzle deterioration due to long-term use, deterioration of an element for ejecting ink, or the like.

  Thus, non-ejection can be reduced in frequency by improving the manufacturing environment and the like, and it has not been a big problem in the past. However, as described above, when the number of nozzles arranged in the recording head is increased in order to increase the speed, there is a problem that cannot be ignored. In particular, in order to manufacture a recording head that does not include a nozzle in a non-ejection state, the manufacturing cost increases and the manufacturing cost increases.

Defects such as white streaks occur on the image due to non-ejection. In order to compensate for such white streaks, a technique has been proposed that uses a divided printing method in which recording is performed by scanning the recording head multiple times, and the white streaks are complemented and recorded by other normal nozzles. Has been.
U.S. Pat. No. 4,723,129 U.S. Pat. No. 4,740,796 US Pat. No. 4,463,359 U.S. Pat. No. 4,345,262 U.S. Pat. No. 4,313,124 U.S. Pat. No. 4,558,333 U.S. Pat. No. 4,459,600 JP 59-123670 A JP 59-138461 A

  However, in the case of the printing system using the above-described high-density and long recording head, it is preferable to perform one-pass printing that completes printing by one scan. However, in this one-pass printing, a portion that is not ejected and is not recorded is preferable. It is very difficult to supplement or make it inconspicuous.

  The present invention reduces non-uniformity of images such as white streaks that occur in a recorded image because dots are not recorded due to non-discharge, and even when non-discharge occurs, non-uniformity of white streaks and images is reduced. An object of the present invention is to provide an ink jet recording apparatus capable of increasing the speed.

In order to achieve the above object, the inkjet recording head of the present invention comprises:
In a printing element substrate where multiple nozzles for discharging liquid and multiple printing elements that generate discharge energy are arranged, they are arranged with a half-pitch of resolution and are complemented by nozzle arrays with the array nozzle density half the recording density. I made it for use.

  As described above, according to the present invention, the decrease in head yield due to undischarge, which is particularly noticeable in a full multi-head, can be eliminated, and it is extremely effective for the head cost. Further, by providing the apparatus with a detection means for non-discharge occurring during use, it is possible to perform complementation using a corresponding complementary nozzle while minimizing image deterioration, and to reduce the frequency of head replacement. it can.

  It is possible to provide a recording apparatus capable of more continuous high-quality printing.

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

(First embodiment)
FIG. 1 to FIG. 6 are explanatory diagrams for explaining each of the preferred 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 electrothermal transducer that generates thermal energy for generating thermal energy for causing film boiling to the ink in accordance with an electrical signal. The recording head is a bubble shooter (registered trademark) side shooter type that performs recording using the.

  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 plate H1200, an electric wiring substrate H1300, a second plate H1400, and a filter 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 consisting 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 plate H1200 is made of, for example, an alumina (Al2O3) material having a thickness of 0.5 to 10 mm. The material of the first plate is not limited to alumina, and has a linear expansion coefficient equivalent to that of the material of the recording element substrate H1100 and is equivalent to the thermal conductivity of the material of the recording element substrate H1100. Alternatively, it may be made of a material having an equivalent or higher thermal conductivity. The material of the first plate H1200 is, for example, any of silicon (Si), aluminum nitride (AlN), zirconia, silicon nitride (Si3N4), silicon carbide (SiC), molybdenum (Mo), and tungsten (W). May be. An ink supply port H1201 for supplying ink to the recording element substrate H1100 is formed in the first plate H1200, and the ink supply port H1101 of the recording element substrate H1100 is connected to the ink supply port H1201 of the first plate H1200. Correspondingly, the recording element substrate H1100 is bonded and fixed to the first plate 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 plate H1200 has an X-direction reference H1204, a Y-direction reference H1205, and a Z-direction reference H1206, which are positioning references.

  The recording element substrates H1100 are arranged in a staggered manner on the first plate H1200 as shown in FIG. 1, and wide recording with the same color is possible. For example, four recording element substrates H1100a, H1100b, H1100c, and H1100d each having a nozzle group length of 1 inch + α are arranged in a staggered manner to enable recording of a width of 4 inches.

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

  A groove formed by the opening H1402 of the second 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.

  Further, a filter member H1600 for removing foreign matters mixed in the ink is bonded and fixed to the back surface side ink supply port H1201 of the first plate H1100.

(1-2) Ink Supply Unit The ink supply member H1500 is formed by resin molding, for example, 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, a screw H1900. 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 back surface of the ink supply member H1501, for example.

(2) 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.

  Next, with reference to FIGS. 6 to 9, the arrangement of nozzles and the arrangement of recording heads, which are characteristic parts of the present invention, and actual printing will be described.

  FIG. 6 schematically shows the nozzle arrangement of the recording element substrate described above. There are four nozzle groups arranged perpendicular to the paper feed direction, and the two nozzle groups are arranged to form the pixel density. That is, one nozzle group is arranged at a double pitch of the pixel pitch, and the two nozzle groups are arranged by shifting one pixel from each other. Two sets of this combination are provided. This configuration is a nozzle arrangement that enables an effect equivalent to two passes within one chip. Further, nozzles for forming adjacent dots, for example, A1 and B1, are arranged at a distance of a desired length Ln in order to provide a landing time difference between adjacent dots. When printing between dots at 10 kHz, a time difference of about 10 ms occurs when Ln = 2 mm. Although depending on the ink and the recording medium, it is possible to take a time difference in which the other dot lands after the adjacent dot penetrates into the medium, and it is possible to avoid image deterioration due to the connection of dots. Further, when placed in the paper transport direction, printing is performed by alternately using A1 and D1. In the present invention, a non-discharge complementing nozzle group is arranged separately from the normally used nozzles. In the discharge failure complement nozzle group, the nozzles are arranged at a pitch twice that of the head resolution, and are shifted by a half pitch with respect to the normally used nozzles.

  FIG. 7A shows a schematic diagram of a recording state with an ejection failure nozzle when recording is performed in this embodiment, and FIG. 7B is a schematic schematic diagram of a dot recording state when complemented. Nozzles marked with x are undischargeable nozzles. Dots are formed by a storage nozzle shifted by half a dot with respect to this nozzle. Since it is shifted by half a dot, it cannot be completely superimposed on the original dot position with respect to the undischarged dot, but it can be almost made up.

  In particular, in the case of a nozzle configuration corresponding to two passes as in the present embodiment, one line is recorded using two nozzles in one line in the paper feed direction. Therefore, even if one of the nozzles fails to discharge, it is completely white. It does not become a streak, and it becomes possible to record without conspicuous enough with the complementary nozzle of the present invention.

  FIG. 8 shows an embodiment in which one nozzle group is provided and complementary nozzles are provided in the same arrangement relationship as described above.

  FIG. 9A shows a non-ejection situation occurring in this nozzle arrangement, and FIG. In this case, unlike the case corresponding to two passes as described above, the undischarged line is filled in a line that is completely shifted by half a dot.

  Although the complementary dot diameter is the same as the dot diameter of normal recording, setting it slightly larger is effective for white stripes.

  In addition, regarding discharge failure complementation, a method of performing complementary dot placement in combination with image correction can be used.

  In this way, in the present invention, since the dots are shifted by half a pitch with respect to the normal recording dot position, two pixels in the nozzle arrangement direction can be handled by one complementary nozzle, and the complementary nozzle is It can be significantly reduced.

  Examples of the ink jet recording method that can realize the nozzle group as described above relatively easily and at a low cost include, but are not limited to, the following.

  The present invention provides an excellent effect particularly in a recording apparatus using an ink jet recording head that performs recording by forming flying droplets using thermal energy among ink jet recording methods.

  As its typical configuration and principle, for example, those performed using the basic principle disclosed in US Pat. Nos. 4,723,129 and 4,740,796 are preferable. This method can be applied to both the so-called on-demand type and continuous type. In particular, in the case of the on-demand type, it is arranged corresponding to the sheet or liquid path holding the liquid (ink). By applying at least one drive signal corresponding to the recording information and giving a rapid temperature rise exceeding nucleate boiling to the electrothermal transducer, the thermal energy is generated in the electrothermal transducer, and the recording head This is effective because film boiling occurs on the heat acting surface, and as a result, bubbles in the liquid (ink) corresponding to the drive signal can be formed. By the growth and contraction of the bubbles, liquid (ink) is ejected through the ejection opening to form at least one droplet. It is more preferable that the drive signal has a pulse shape, since the bubble growth and contraction is performed immediately and appropriately, and thus it is possible to achieve discharge of a liquid (ink) having particularly excellent responsiveness. As this pulse-shaped drive signal, those described in US Pat. Nos. 4,463,359 and 4,345,262 are suitable. Further excellent recording can be performed by employing the conditions described in US Pat. No. 4,313,124 of the invention relating to the temperature rise rate of the heat acting surface.

  As the configuration of the recording head, in addition to the combination configuration (straight liquid channel or right-angle liquid channel) of the discharge port, the liquid channel, and the electrothermal transducer as disclosed in each of the above-mentioned specifications, the thermal action A configuration using US Pat. No. 4,558,333 and US Pat. No. 4,459,600, which disclose a configuration in which the portion is arranged in a bent region, is also included in the present invention.

  In addition, for a plurality of electrothermal transducers, Japanese Patent Application Laid-Open No. Sho 59-123670 that discloses a configuration in which a common slit is used as a discharge portion of the electrothermal transducer or an aperture that absorbs pressure waves of thermal energy is provided. The effect of the present invention is also effective as a configuration based on Japanese Patent Application Laid-Open No. 59-138461 which discloses a configuration corresponding to the discharge unit. That is, whatever the form of the recording head is, according to the present invention, recording can be performed reliably and efficiently.

  Furthermore, the present invention can be effectively applied to a full-line type recording head having a length corresponding to the maximum width of the printing material that can be recorded by the recording apparatus. As such a recording head, either a configuration satisfying the length by a combination of a plurality of recording heads or a configuration as a single recording head formed integrally may be used.

  In addition, even the serial type as shown in the above example can be connected to the main body of the recording head or attached to the main body of the device so that electrical connection with the main body of the device and ink supply from the main body are possible. The present invention is also effective when a replaceable chip type recording head or a cartridge type recording head in which an ink tank is integrally provided in the recording head itself is used.

  In addition, it is preferable to add a recording head ejection recovery means, a preliminary auxiliary means, and the like as the configuration of the recording apparatus of the present invention, since the effects of the present invention can be further stabilized. Specifically, heating is performed using a capping unit, a cleaning unit, a pressurizing or suction unit, an electrothermal transducer, a heating element different from this, or a combination thereof. Examples thereof include a preliminary heating unit for performing the discharge and a preliminary discharge unit for performing discharge different from the recording.

External perspective view of 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. FIG. 6 illustrates an ink jet recording apparatus (full line method). The example schematic diagram of the present invention. The schematic diagram which showed the dot complement in the present invention Example. The other example schematic diagram of this invention. The schematic diagram which showed the dot complementation in other Examples of this invention.

Explanation of symbols

4-1 Recording Head 4-2 Nozzle Group 4-3 Recording Matrix 8-1 to 8-3 Concatenated Dot Shape 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 First plate H1201 Ink supply port H1204 X direction reference H1205 Y direction reference H1206 Z direction reference H1300 Electrical wiring board 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)
H1800 Ink tank H1802 Tube H1900 Screw M4000 Inkjet recording device M4001 Carriage M4002 Electrical contact K1000 Recording medium

Claims (4)

In an inkjet recording head having a recording element substrate in which a plurality of nozzles for discharging a liquid and a plurality of recording elements for generating discharge energy are arranged,
An ink jet recording head, comprising: a complementary nozzle in which nozzles are arranged at a half pitch with respect to the recording density and nozzles are arranged at a pitch twice the recording density.   2. The ink jet recording head according to claim 1, wherein a plurality of the recording element substrates are arranged in a staggered manner.   3. The ink jet recording head according to claim 1, wherein a dot diameter formed by droplets from the complementary nozzle is larger than a dot diameter formed by droplets from the normal recording nozzle.   An ink jet recording apparatus using the ink jet recording head according to claim 1.

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