JP2007261171A - Ink jet recording head and ink jet recording device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable it to suppress consumption of ink by removing completely air bubbles in an ink channel even if the same cap performs suction for the ink and acquiring a high-dignity image in a head on which large dots and small dots are intermingled. <P>SOLUTION: In an ink jet recording head, (1) all output port areas are the same and a discharging amount can be changed by changing a heater size, and (2) all output port area is the same in a configuration which can discharge the large dots and the small dots on both sides of a common ink chamber, and the discharging amount can be changed by changing the volume in the ink channel. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an ink jet recording head and an ink jet recording apparatus for performing recording by causing droplets to fly onto a recording medium such as paper, a resin sheet, or a cloth using thermal energy.

  Inkjet printers are so-called non-impact printing systems, and can print on high-speed prints and various print media, and have the feature that noise during printing hardly occurs. It is widely adopted as a device that bears a printing mechanism such as a word processor, facsimile, or copying machine.

  As a representative example of this ink jet method, a method using an electrothermal conversion element that generates thermal energy as ink droplet ejection energy is known, which ejects minute ink droplets from minute ejection ports, Printing is performed on a print medium such as paper.

  In recent years, particularly in an ink jet printer, there is an increasing demand for color recording and high image quality recording, and in order to achieve high image quality, a configuration that allows gradation expression by changing the dot size is used.

  For example, as shown in FIG. 2, two rows of electrothermal conversion elements H1103a and H1103b parallel to each other across the common ink chamber H1201 are arranged in a so-called zigzag pattern with a half pitch shift, and a functional element circuit formed on the substrate In the configuration in which the drive signal is selectively supplied to each of the electrothermal transducers, the discharge ports H1100Ta and H1100Tb facing the electrothermal conversion elements H1103a and H1103b have different sizes, and as a result, the discharge amount can be changed. Things are known.

  Also, in order to prevent ejection failure due to air bubbles remaining in the ink flow path H1501 from the common ink chamber H1201 to the ejection ports H1100Ta and H1100Tb, for example, the ink is forcibly sucked by the pump from the ejection port side and stays with the ink. Measures have been taken such as eliminating bubbles or performing ink discharge not related to recording at a predetermined position (predetermined sequence) immediately before the start of recording, or performing so-called preliminary discharge.

For example, Patent Document 1 and Patent Document 2 can be cited as conventional examples.
JP-A-8-132624 JP 2003-31964 A

  However, when ink is sucked with the same suction cap from the discharge ports having different sizes as described above, the ink is sucked only from the large discharge port, and the ink is hardly sucked from the small discharge port. It is impossible to completely remove bubbles remaining in the water.

  Furthermore, only a large amount of ink is consumed.

  The present invention has been made in view of such a technical problem, and an object of the present invention is an ink flow path in a configuration in which large dots and small dots can be ejected across a common ink chamber so that the dot size can be changed. It is an object of the present invention to provide an ink jet recording head and an ink jet recording apparatus capable of performing high-quality recording without completely removing bubbles and causing no defective recording and without consuming a large amount of ink.

  An object of the present invention is characterized in that, in a configuration capable of ejecting large dots and small dots across a common ink chamber, all the ejection port areas are the same, but the ejection amounts are different.

  To change the discharge amount, change the size (surface area) of the electrothermal transducer or change the volume in the ink channel (change the discharge amount by changing the ink amount in the ink channel). It is characterized by.

  As described above, according to the present invention, in a head in which large dots and small dots coexist, even if ink suction is performed with the same cap, bubbles in the ink flow path are completely removed, and a high-quality image can be obtained. Ink consumption is also reduced.

Example 1
First, an embodiment according to a recording apparatus of the present invention will be described with reference to the drawings.

  FIG. 1 shows a schematic configuration of a printer using an ink jet recording system.

  As a recording operation mechanism in the present embodiment, an automatic feeding unit M3022 that automatically feeds the recording sheet P into the apparatus main body, and a desired recording sheet P that is sent one by one from the automatic feeding unit. A conveyance unit M3029 for guiding the recording sheet P from the recording position to the discharge unit M3030, a recording unit for performing desired recording on the recording sheet P conveyed to the conveyance unit M3029, and the recording unit The recovery unit M5000 performs recovery processing.

  The recording unit includes a carriage M4001 that is movably supported by a carriage shaft M4021, and a recording head cartridge H1000 that is detachably mounted on the carriage M4001.

  First, the recording head cartridge will be described with reference to FIGS.

  As shown in FIG. 3, the recording head cartridge H1000 in this embodiment has an ink tank H1900 that stores ink, and a recording head H1001 that discharges ink supplied from the ink tank H1900 from nozzles according to recording information. The recording head H1001 adopts a so-called cartridge system that is detachably mounted on a carriage M4001 described later.

  Each of the ink tanks H1900 is detachable from the recording head H1001.

  As shown in the exploded perspective view of FIG. 4, the recording head H1001 includes a recording element substrate H1100, a first plate H1200, an electrical wiring substrate H1300, a second plate H1400, a tank holder H1500, a flow path forming member H1600, It consists of filter H1700 and seal rubber H1800.

  In the recording element substrate H1100, a plurality of recording elements for ejecting ink to one side of the Si substrate and electric wiring such as Al for supplying electric power to each recording element are formed by a film forming technique. A plurality of corresponding ink flow paths and a plurality of discharge ports H1100T are formed by a photolithography technique.

  The recording element substrate H1100 is bonded and fixed to a first plate H1200, and a common ink chamber H1201 for supplying ink to the recording element substrate H1100 is formed therein.

  Further, a second plate H1400 having an opening is bonded and fixed to the first plate H1200, and this second plate H1400 is electrically connected to the electric wiring board H1300 and the recording element board H1100. The electric wiring board H1300 is held. This electrical wiring substrate H1300 applies an electrical signal for ejecting ink to the recording element substrate H1100, and the electrical wiring corresponding to the recording element substrate H1100 is located at the end of the electrical wiring and from the main body. An external signal input terminal H1301 for receiving an electric signal is positioned and fixed on the back side of the tank holder H1500.

  In addition, a cap M5001 used for capping for contact with the recording head H1001 for suction recovery processing and drying prevention of the recording head H1001, and a recovery pump M5100 communicating with the cap M5001 are arranged.

  FIG. 5 is a partially cutaway perspective view showing the recording element substrate H1100 provided in the ink jet recording head H1001 shown in FIGS. 3 and 4 in an enlarged manner.

  Ink is supplied from the ink tank H1900 to the recording element substrate H1100 of the recording head H1001.

  The recording element substrate H1100 is provided with a plurality of ejection ports H1100T arranged in a staggered manner on both sides of the ink supply port H1201, and generates thermal energy used to eject ink liquid from each of the ejection ports H1100T. The electrothermal conversion element H1103 is provided on a base H1101 made of silicon for each ink flow path H1501.

  In the ink jet recording head having the above-described configuration, the ink is held by forming a meniscus in the vicinity of the plurality of ejection ports H1100T. At this time, by selectively driving the electrothermal conversion element H1110 according to the recording information of the image, the ink on the heat acting surface is rapidly heated and boiled using the generated heat energy. Ink is ejected from the ejection port H1100T through the ink flow path H1501 from the common ink chamber H1201 by pressure.

  The ink liquid is attached to a recording medium such as a sheet sent to a position facing the recording head, and desired image recording is performed.

  Next, the present embodiment will be described in detail with reference to FIGS.

FIG. 6 shows an electrothermal conversion element and an ink flow path section. The electrothermal conversion element H1103a is 26 μm × 26 μm, and the electrothermal conversion element H1103 is The size of the electrothermal conversion element H1103a is 22 μm × 22 μm. However, the discharge ports H1100 are both the same size and 201 μm ² .

  That is, the row of electrothermal transducers H1103a ejects large dots and the row of electrothermal transducers H1103b ejects small dots.

  7 and 8 are cross-sectional views of the flow path, but the ink flow path H1501 is bent at the electrothermal conversion elements H1103a and H1103b, and the electrothermal conversion elements H1103a and H1103b and the ejection port H1100T face each other. Reference numeral 1104 denotes an orifice plate that forms an ink flow path H1501 and an ejection port H1100T.

  FIG. 7 is a cross-sectional view of a flow path for large dots, and FIG. 8 is a cross-sectional view of a flow path for small dots.

  The large dot has a small thickness t1 in the portion of the orifice plate 1104 forming the discharge port, and the small dot has a large thickness (t2). That is, the height of the ink flow path H1501 is different, the large dots are high in the ink flow path H1501, and the small dots are low.

  In this embodiment, the discharge amount for large dots is 5 pl, and the discharge amount for small dots is 2 pl.

  The thickness of t1 is 11 μm, and the thickness of t2 is 13 μm. However, the distance T from the ejection port to the bottom surface of the ink flow path is the same 25 μm.

  In yet another example, the volume in the ink flow path is changed by changing the distances t3 and t4 from the ejection port to the bottom surface of the ink flow path as shown in FIGS.

  However, here, the thickness R of the portion of the orifice plate 1104 forming the discharge port is not changed. That is, the height of the ink flow path is different, and the large dot is high in the ink flow path H1501, and the small dot is low.

Specifically, the distance t3 from the discharge port of the large dot to the bottom surface of the ink flow path is 25 μm, the distance t4 from the discharge port of the small dot to the bottom surface of the flow path is 23 μm, and the discharge port of the orifice plate 1104 is formed. The thickness R of each of the large dots and the small dots is 11 μm.

  In other words, the large dot has a height of the ink flow path H1501 of 14 μm, the small dot has a height of 12 μm, and the large dot is higher.

  With such a configuration, the volume in the ink flow path becomes larger for the large dot, and the combination of this volume difference and the size difference of the electrothermal conversion element described above makes the discharge amount different even if the discharge port is the same. It can be made.

  However, the heater size and the ink flow path configuration vary depending on the combination and discharge amount.

  Since the large nozzle and small dot ejection port diameters can be made the same in this way, even if ink is sucked with the same cap, both can suck the same amount of ink. Can be completely removed, and a high-quality image can be obtained. Furthermore, a large amount of ink is not consumed.

(Example 2)
As in Example 1, two rows of electrothermal conversion elements are arranged across the common ink chamber H1201, the electrothermal conversion element H1103a is 26 μm × 26 μm, the electrothermal conversion element H1103b is 22 μm × 22 μm, and the electrothermal conversion element H1103a Is large in size. However, the discharge port H1100T is both the same size and 201 μm ² . That is, the row of electrothermal transducers H1103a ejects large dots and the row of electrothermal transducers H1103b ejects small dots.

  FIG. 11 is a detailed view of the ink flow path and the electrothermal conversion element portion of this embodiment.

  In this embodiment, the length t5 of the ink flow path H1501 of the large dot row and the length t6 of the ink flow path H1501 of the small dot row are different, and the length of t5 is longer. Yes.

In this embodiment, the discharge amount for large dots is 5 pl, and the discharge amount for small dots is 2 pl.
The distance t6 from the center of the common ink chamber H1201 to the heater center of the large dot is 117 μm, and the distance t5 to the heater center of the small dot is 97 μm, and the distance of the large dot is longer.

  Other ink channel dimensions (for example, ink channel width and height, distance from the ejection port to the bottom surface of the ink channel, etc.) are the same.

  By doing so, the volume in the ink flow path is different between the large dot and the small dot, and by combining this with the size difference of the electrothermal conversion element, the discharge amount can be made different even if the discharge port diameter is the same.

  Furthermore, since the large nozzle and the small dot can have the same discharge port diameter in this way, even if ink suction is performed with the same cap, both can suck the same amount of ink. The bubbles can be completely removed, and a high-quality image can be obtained. Furthermore, a large amount of ink is not consumed.

It is a perspective view which shows the state which removed the exterior member of the inkjet printer in embodiment of this invention. FIG. 3 is a cross-sectional view illustrating an internal structure of a recording head used in an embodiment of the present invention. FIG. 3 is a perspective view showing a state in which the recording head cartridge used in the embodiment of the invention is assembled. FIG. 3 is an exploded perspective view of the recording head used in the embodiment of the present invention as viewed obliquely from below. FIG. 2 is an enlarged cross-sectional perspective view of a recording element substrate of a recording head used in an embodiment of the present invention. It is an expanded sectional view of the internal structure shown in FIG. 2 is a cross-sectional view of a large dot channel in Example 1. FIG. 3 is a cross-sectional view of a small dot channel in Example 1. FIG. 6 is a cross-sectional view of a flow path for a large dot in another example in Embodiment 1. FIG. 6 is a cross-sectional view of a small dot channel according to another example of Embodiment 1. FIG. 6 is an enlarged cross-sectional view of an internal structure in Example 2. FIG.

Explanation of symbols

E0001 Carriage motor
H1100T Discharge port
H1900 ink tank
E0002 LF motor
H1100Ta Large dot outlet
M2015 Paper gap adjustment lever
H1100Tb Small dot outlet
M3001 LF roller
H1101 Substrate made of silicon
M3019 chassis
H1103 electrothermal transducer
M3022 Automatic feeding unit
H1103a Electrothermal transducer for large dots
M3029 Transport unit
H1103b Electrothermal transducer for small dots
M3030 Discharge section
H1104 Orifice plate
M4001 carriage
H1200 1st plate
M4002 Carriage cover
H120 Common ink chamber
M4007 Headset lever
H130 Electric wiring board
M4021 Carriage shaft
H1301 External signal input terminal
M5000 recovery unit
H140 2nd plate
M5001 cap
H1500 tank holder
M5100 recovery pump
H1501 ink flow path
H1000 print head cartridge
H1600 Channel forming member
H1001 Recording head
H1700 filter
H1100 Recording element substrate
H1800 rubber seal

Claims (5)

An electrothermal conversion element that generates thermal energy used for discharging the liquid, a discharge port that discharges the liquid provided at a position facing the electrothermal conversion element, and the liquid that communicates with the discharge port Liquid to be discharged in a liquid discharge head including a liquid flow path that is supplied to the discharge port and has the electrothermal conversion element on a bottom surface, and a common liquid chamber that is connected to each of the liquid flow paths and is supplied with liquid. An ink jet recording head characterized in that, as means for adjusting the discharge amount, the area of the discharge port is the same and the size of the electrothermal conversion element is different.   2. The ink jet recording head according to claim 1, wherein, as means for adjusting the discharge amount of the liquid to be discharged, the area of the discharge port is the same and the volume in the liquid flow path is different.   The liquid channel is characterized in that the height from the electrothermal conversion element to the ceiling of the liquid channel is higher in the liquid channel for discharging large dots than in the liquid channel for discharging small dots. 2. An ink jet recording head according to 2.   3. The liquid flow path according to claim 2, wherein the distance from the common liquid chamber to the electrothermal conversion element is longer in the liquid flow path for discharging large dots than in the liquid flow path for discharging small dots. The inkjet recording head described.   An electrothermal conversion element that generates thermal energy used for discharging the liquid, a discharge port that discharges the liquid provided at a position facing the electrothermal conversion element, and the liquid that communicates with the discharge port Inkjet recording using a liquid discharge head that includes a liquid flow path that is supplied to the discharge port and has the electrothermal conversion element on the bottom surface, and a common liquid chamber that is connected to the liquid flow paths and is supplied with liquid. An ink jet recording apparatus using an ink jet recording head, characterized in that, as means for adjusting a discharge amount of a liquid to be discharged, the area of the discharge port is the same and the size of the electrothermal conversion element is different.

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