JP2007076236A - Inkjet cartridge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inkjet cartridge which does not affect a head size, does not require an additional process in the formation of a bubble buffer chamber, keeps a stable discharging state by suppressing an ink vibration in a passage at the time of an ink discharge by the formation of the bubble buffer chamber having a filter deformation-preventing function as well, and by which images of a high grade are always obtained. <P>SOLUTION: An inkjet recording head comprises a recording element board, and an ink passage. In this case, the recording element board has a discharging port for discharging an ink, and a discharge energy generating element which generates an energy for discharging the ink. The ink passage can hold an ink housing section which stores the ink being fed to the recording element board, and communicates with the discharging port. In the inkjet recording head, the connection between the ink housing section and the ink passage has a protruding section which constitutes a filter holding section and a protruding section, and is brought into contact with the ink housing section. Then, a buffer chamber which makes a gas exist is provided in the protruding section. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an ink jet recording head that performs recording by ejecting ink onto a recording medium such as paper or cloth, an ink jet cartridge, and a printing apparatus using the recording head.

  Conventional printing apparatuses such as printers, copiers, and facsimile machines are configured to record an image formed of a dot pattern on a recording material based on image information. The printing device can be divided into an ink jet method, a wire dot method, a thermal method, a laser beam method, and the like according to the printing method. Among them, the ink jet method includes an ink jet recording head, in order to eject ink into the liquid path. Energy conversion means for generating ejection energy to be used, and the ink is led from the ink supply port to the liquid path through the liquid chamber, and the ink is ejected by the ejection energy given from the energy conversion means to the ink. The droplets are made to fly toward the recording material and are recorded by the landing. In particular, inkjet recording heads that eject ink using thermal energy can arrange the ink ejection ports for ejecting ink droplets for recording to form flying droplets at high density. In particular, it has been put into practical use because of its advantages such as easy compactness.

  In recent years, due to the demand for high-speed recording, the number of nozzles arranged in the ink jet recording head has been increased, and the flow rate of ink flowing through the ink flow path has been increased.

  In an ink jet recording head, it is generally used to provide a filter for trapping dust in the ink flow path in order to prevent clogging of dust at the ink discharge port. In order to prevent ejection failure due to insufficient ink supply, it is necessary to reduce the pressure loss due to the filter by increasing or decreasing the filter area. However, if the filter area is made large or thin, the filter is likely to be deformed, and there is a risk that ejection failure may occur due to the deformation. Furthermore, in order to handle fluid ink in the ink jet system, the ink flow rate per unit time increases especially in an ink jet recording head arranged in a multi-nozzle with a high density, and the ink of the tank system when the discharge is stopped The inertial force that tends to move to the nozzle is also large, and this inertial force causes a positive pressure on the nozzle, causing the meniscus to protrude. At this time, when the next print signal is input, small ink droplets are scattered, so-called splash-like printing is performed. Thus, when the meniscus vibration is greatly disturbed by the ink vibration, the image quality may be deteriorated.

  FIG. 5 is a diagram showing a pressure oscillation waveform in the ink flow path with respect to an ejection pulse when a predetermined ejection is performed by a conventional inkjet recording head. FIG. 6 is a section A (before ejection start) and B in FIG. FIG. 6 is a nozzle cross-sectional view illustrating a state of a meniscus in a section (during discharge operation) and a section C (after discharge is stopped). The amplitude of the pressure vibration in the flow channel after stopping the discharge becomes a large positive pressure, and this vibration disturbs the meniscus vibration during the next discharge. Specifically, in section A in FIG. 5, a stable meniscus M is formed as shown in FIG. 6 (A), and when the discharge operation is performed in this state as in section B, it is good as shown in FIG. 6 (B). New droplet 50 is produced. Then, when entering the C section immediately after stopping the discharge, the pressure in the flow path 52 becomes a large positive pressure due to the inertia of the liquid movement toward the discharge port 51, and rises to the discharge port forming surface as shown in FIG. 6 (C). In this state, a meniscus M is formed, or in the worst case, ink drips from the ejection port 51. Therefore, when the next ejection is started in the state of FIG. 6C, small ink droplets are scattered, and good printing cannot be performed as described above. As a method for solving such a phenomenon, the flow resistance is adjusted by changing the filter diameter and the ink flow path to stabilize the meniscus vibration. Further, there is a method of absorbing pressure vibration by providing a buffer chamber in a liquid chamber or a flow path to provide bubbles. This is perfect as a means for suppressing pressure vibration, and is used in many ink jet recording heads. Among them, as a means for suppressing pressure vibration, there is a method of forming a bubble buffer chamber in a liquid chamber (Japanese Patent Laid-Open No. 6-210872). In this case, since the buffer chamber is provided in the common liquid chamber, the buffer volume and shape are not flexible. In addition, since there are bubbles in the vicinity of the nozzle, there is a high risk of ink ejection failure due to bubble growth. Further, Japanese Patent Laid-Open No. 2002-144602 discloses a method of drawing a communication path from an ink flow path by coupling a flow path forming member to form a bubble buffer outside. However, in this case, since the process for joining the flow path member is required together with the number of parts, the cost increases. Although there is a means for forming a buffer chamber by providing a through passage communicating with the ink flow path, a member and a process for closing the through portion are required, and the cost is also increased as described above. There is also a method of drawing a communication path from the ink flow path and the liquid chamber to the outside, forming a buffer chamber, and sealing with a recording element substrate having an ejection port. However, the recording element substrate needs to be large and the inkjet recording head is large. At the same time, the cost increases as described above.

In the buffer chamber configuration, when the interface between the gas and the ink in the buffer chamber is close to the liquid chamber and the flow path formation space, the gas in the buffer chamber enters the ink flow path and the liquid chamber due to pressure fluctuations due to ink discharge and ink suction operations. There is a risk of mixing and causing printing defects.
Japanese Patent Laid-Open No. 6-210872 JP 2002-144602 A

  The present invention has been made to solve the above-described problems, and is a compact ink-jet cartridge that secures a cost advantage and does not cause printing defects due to filter deformation, and is accompanied by ink ejection. An object of the present invention is to provide an ink jet cartridge that suppresses ink ejection instability due to ink vibration and a recording apparatus equipped with the ink jet cartridge.

  A recording element substrate having an ejection port for ejecting ink and an ejection energy generating element for generating energy for ejecting ink, and an ink containing portion for storing ink to be supplied to the recording element substrate can be held. In the ink jet recording head having an ink flow path communicating with the ejection port, the connection between the ink containing portion and the ink flow path has a filter holding portion and a convex portion that forms an ink flow path and comes into contact with the ink containing portion, The present invention proposes an ink jet recording head characterized in that a buffer chamber for allowing gas to exist is provided on the convex portion.

  It is preferable that one of the buffer chambers has a protruding shape close to the filter, and one of the buffer chambers is opened toward the discharge port and gas is present inside.

  Furthermore, it is preferable that the buffer chamber is an open space that opens at both ends, one of which is open toward the discharge port, and the opposite opening is in contact with the filter.

  In addition, the cross-sectional area of the buffer chamber is configured to gradually increase from the discharge port side opening toward the center of the buffer chamber, and ink is held in the narrow space of the discharge port side opening of the buffer chamber. Is preferred.

  In addition, it is preferable that the discharge port provided in the filter and the recording element substrate is linearly connected via the ink flow path, and the filter and the discharge port are configured to face each other.

(Function)
With the above configuration, in the ink jet recording head and the recording apparatus equipped with the ink jet recording head, the cost advantage is ensured, the compactness is excellent, the printing defect due to the filter deformation is not caused, and the ink accompanying the ink ejection Instability of ink ejection due to vibration can be suppressed and a high-quality image can always be obtained.

  As described above, the ink jet cartridge of the present invention is configured to form a bubble buffer chamber in which gas exists in a chimney portion to which a filter of an ink container is attached, and the bubble buffer chamber is close to or abuts the filter. Therefore, it ensures cost superiority and is excellent in compactness, does not cause printing defects due to filter deformation, and further suppresses ink ejection instability due to ink vibration accompanying ink ejection, and always obtains high-quality images. Effective. In addition, an opening is formed in which one of the bubble buffer chambers faces the recording element substrate to communicate with the ink supply path, and the other is also in contact with the filter as a penetrating structure that opens. By configuring the narrow tube portion smaller than the space cross-sectional area, there is an effect that the gas can be more stably present in the bubble buffer chamber against the environmental change.

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

(First embodiment)
FIG. 3 is a schematic view showing the configuration of the ink jet cartridge according to the first embodiment of the present invention. FIG. 3 (a) is a schematic exploded perspective view, and FIG. 3 (b) is an assembled perspective view. The recording element substrate mounted on the ink jet cartridge H1001 is a bubble jet (registered trademark) type recording using an electrothermal transducer that generates thermal energy for causing film boiling of ink according to an electrical signal. It is a so-called side shooter type ink jet recording head, which is a head and is disposed so that the electrothermal transducer and the ink discharge port face each other. In this embodiment, the method using an electrothermal transducer is used, but it is also an effective means for an ink jet recording head that ejects ink using a piezo element that converts an electric signal into pressure vibration.

  As shown in the exploded perspective view of FIG. 3A, the ink jet cartridge H1001 includes a recording element substrate H1100 and an ink storage container H1003. The recording element substrate H1100 is attached and fixed to the ink storage container H1003 by adhesion. The The electric flexible cable H1300 is formed by forming wiring on a TAB (Tape Automated Bonding) tape, has flexibility, and is bent and fixed to an ink container.

  The ink absorber H1004 that holds ink and generates negative pressure is inserted into the ink container H1003 in a compressed state. Thereafter, ink is injected into the ink container H1003, and the lid H1005 is welded and fixed to the ink container H1003.

  FIG. 4 is a partially cutaway perspective view illustrating the configuration of the first recording element substrate H1100 for black ink that is frequently used. In the first recording element substrate H1100, for example, a common liquid chamber H1102 that is a long groove-like through-hole that is an ink flow path is formed in a Si substrate H1110 having a thickness of 0.5 to 1 mm. On both sides of the common liquid chamber H1102, the electrothermal conversion elements H1103 are arranged and arranged in a line, and electric wiring (not shown) made of Al or the like for supplying electric power to the electrothermal conversion elements H1103. Is formed. These electrothermal conversion elements H1103 and electric wiring are formed by a film forming technique. The electrothermal conversion elements H1103 are arranged in a staggered manner in each row, that is, the positions of the ejection ports in each row are slightly shifted so as not to line up in a direction orthogonal to the row direction. Furthermore, electrode portions H1104 for supplying electric power to the electric wiring are formed along the outer sides of the electrothermal transducer H1103, and bumps H1105 made of Au or the like are formed on the electrode portions H1104. Is formed.

  On the surface of the Si substrate H1110 on which these are formed, there is an ink flow path wall H1106 that forms an ink flow path corresponding to the electrothermal conversion element H1103 and a ceiling portion that covers the ink flow path wall H1106. A structure made of a resin material, in which a discharge port H1107 is opened, is formed by photolithography. The discharge port 1107 is provided to face the electrothermal conversion element H1103, and forms a discharge port group H1108. In the first recording element H1100, the ink supplied from the ink flow path H1102 is ejected from the ejection port 1107 facing each electrothermal conversion element H1103 by the pressure of the bubbles generated by the heat generated by each electrothermal conversion element H1103. The

  The common liquid chambers 1102 of the recording element substrate H1100 are connected so as to communicate with the ink supply path H1006 of the ink storage container H1003, respectively, and are bonded and fixed so as to be accurately positioned with respect to the ink storage container H1003.

  The electric flexible cable H1300 forms an electric signal path for applying an electric signal for ejecting ink to the recording element substrate H1100. An opening corresponding to the recording element substrate H1100 is formed in the electric flexible cable H1300. Near the edge of the opening, electrode terminals (not shown) connected to the electrode portions H1104 of the respective recording element substrates H1100 are formed, and on the opposite side of the joint-side end to the recording element substrate H1100, the main body and A contact pad H1301 to be electrically bonded is formed. The electric flexible cable H1300 is bonded and fixed to the ink container H1003 with an adhesive on the back surface, and further bent to one side of the ink container H1003 and bonded and fixed to the side surface of the ink container H1003. The electrical connection between the electric flexible cable H1300 and the recording element substrate H1100 is performed, for example, by electrically joining the recording element substrate H1100 and the electrode terminal of the electric flexible cable H1300 by a thermal ultrasonic pressure bonding method. The electrical connection portion between the first recording element substrate H1100 and the electric flexible cable H1300 is sealed with a sealant, thereby protecting the electrical connection portion from ink corrosion and external impact.

  FIG. 1 is a schematic cross-sectional view showing a cross section in the ejection port array direction in the recording element substrate H1100 of the ink jet cartridge shown in FIG. A filter H1007 is configured between the ink absorber H1005 that holds ink and the ink supply path H1006 in order to prevent foreign matters such as dust from entering. The filter H1007 is welded and fixed to the ink container H1003, the filter mounting portion has a chimney H1008 that is convex in the ink container, and the filter H1007 is pressed against the ink absorber H1005. A bubble buffer chamber H1009 is provided in the chimney H1008 together with the ink supply path H1006 to allow gas to exist inside. At this time, one of the bubble buffer chambers H1009 is in communication with the ink flow path H1006 with one side facing the recording element substrate H1100, and the other is closed to make the bubble buffer chamber H1009 a closed space. When the bubble buffer chamber H1009 is configured in this way, the bubble buffer chamber H1009 is formed substantially parallel to the ink flow direction in the ink flow path H1010 during ink ejection or ink suction operation by an ink jet recording apparatus (not shown). In addition, since the opening is formed in the same direction as the ink flow direction, it is possible to avoid ink intrusion into the bubble buffer chamber H1009 during ink discharge and ink suction. As a result, a closed space in which gas is present is formed in the ink flow path H1010, and pressure vibrations that occur during ink ejection can be suppressed. FIG. 7 shows the pressure vibration waveform in the flow path during ink discharge in the present embodiment, and it can be seen that pressure vibration after ink discharge is suppressed. Further, the bubble buffer chamber H1009 has a convex shape close to the filter H1007, prevents deformation of the filter H1007 due to pressure contact with the ink absorber H1005, etc., and enables stable ink supply. In this embodiment, an ink jet cartridge in which an ink storage container and a recording element substrate H1100 constituting an ink discharge portion are integrally formed is used. However, the present invention is not limited to this, and the ink storage portion can be separated. It is possible to apply to an inkjet cartridge.

  In this embodiment, the bubble buffer chamber is formed in the supply path of the single-color inkjet cartridge. However, the bubble buffer chamber can be similarly formed in the inkjet cartridge having a plurality of color ink supply paths. is there.

According to this configuration, in the ink jet recording head and the recording apparatus equipped with the ink jet recording head, the cost advantage is ensured, the compactness is excellent, the print defect due to the filter deformation is not caused, and the ink discharge is accompanied. Ink ejection instability due to ink vibration can be suppressed and a high-quality image can always be obtained (second embodiment).
FIG. 2 is a schematic cross-sectional view showing an ink jet cartridge according to the second embodiment of the present invention. The bubble buffer chamber H2009 has a different configuration from the ink jet recording head according to the first embodiment. The same components as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted. In FIG. 2, the bubble buffer chamber H2009 has a penetrating structure in which one side is formed with an opening facing the recording element substrate H1100 and communicates with the ink flow path H1006, and the other is opened toward the filter H1007. The bubble buffer chamber H2009 is in contact with the filter H1007 and is closed by the filter H1007 holding the ink meniscus. Further, the bubble buffer chamber H2009 is formed with a narrow tube portion H2010 in which the opening area on the recording element substrate H1100 side is smaller than the buffer chamber space sectional area. Then, after the pressure inside the bubble buffer chamber H2009 is reduced at the time of ink injection or by the initial suction operation, the suction buffer is stopped and the negative pressure in the bubble buffer chamber H2009 is canceled, and the ink is drawn into the narrow tube portion H2010, and the ink is held. The interface between the gas and the ink in the bubble buffer chamber H2009 usually exists in the narrow tube portion H2010, and the volume of the narrow tube portion H2010 and the initial ink retention amount are in the bubble buffer chamber H2010 due to pressure reduction and temperature change during normal use and physical distribution. The pressure is adjusted so as not to be discharged into the ink supply path H1006 by the decompression operation. Furthermore, the capillary volume and the amount of ink retained are adjusted so that ink does not enter the bubble buffer chamber even when the ink interface in the capillary tube H2010 moves toward the bubble buffer chamber H2009 due to vibration or environmental temperature change. By changing the opening cross-sectional area stepwise, ink can be prevented from entering the bubble buffer chamber H2010 due to the meniscus force of the opening cross-sectional area changing portion even in the case of irregular ink movement in the narrow tube H2010. Is possible.

  According to this configuration, in the ink jet recording head and the recording apparatus equipped with the ink jet recording head, the cost advantage is ensured, the compactness is excellent, the printing defect due to the filter deformation is not caused, and the ink accompanying the ink ejection is further increased. Instability of ink ejection due to vibration can be suppressed and a high-quality image can be always obtained, and gas can be stably present in the bubble buffer chamber.

It is a typical sectional view showing the ink jet cartridge in a first embodiment of the present invention. It is typical sectional drawing which shows the inkjet cartridge in the 2nd Embodiment of this invention. 3A and 3B are schematic views of the ink jet cartridge according to the embodiment of the present invention, in which FIG. 3A is an exploded perspective view, and FIG. 3B is an assembled perspective view. FIG. 4 is a schematic perspective view showing a recording element substrate in the ink jet cartridge of FIG. FIG. 10 is a diagram illustrating a pressure oscillation waveform in an ink flow path with respect to an ejection pulse when a predetermined ejection is performed by a conventional inkjet recording head. FIG. 6 is a nozzle cross-sectional view illustrating a meniscus state in an A section (before discharge start), a B section (during discharge operation), and a C section (immediately after discharge stop) in FIG. 5. It is a figure which shows the pressure oscillation waveform in the flow path of the inkjet recording head of this invention.

Explanation of symbols

350 Ink droplet 351 Discharge port 352 Liquid flow path 353 Heater 371 Liquid flow path H1001 Inkjet cartridge H1002, H2002 Liquid discharge head unit H1003 Ink container H1004 Ink absorber H1005 Cover H1006 Ink supply path H1007 Filter H1008 Chimney H1009, H2009 Bubble Buffer chamber H2010 Narrow tube portion H1100 Recording element substrate H1102 Common liquid chamber H1103 Electrothermal conversion element H1104 Electrode portion H1105 Bump H1106 Ink channel wall H1107 Discharge port H1108 Discharge port group H1110 Si substrate H1200 First plate H1201 Liquid supply channel H1202 Screw fixing part H1300 Electric / electric flexible cable H1301 Electrode pad

Claims (6)

  A recording element substrate having an ejection port for ejecting ink and an ejection energy generating element for generating energy for ejecting ink, and an ink containing portion for storing ink to be supplied to the recording element substrate can be held. In an ink jet cartridge having an ink flow path communicating with an ejection port, the connection between the ink storage portion and the ink flow path is made via a convex portion that forms a filter holding portion and an ink flow path and contacts the ink storage portion. An ink jet cartridge comprising a buffer chamber for allowing gas to exist in the convex portion.   2. The ink jet cartridge according to claim 1, wherein one of the buffer chambers has a protruding shape close to the filter, and one of the buffer chambers is opened toward the discharge port, and gas is present inside the buffer chamber.   3. The ink jet cartridge according to claim 2, wherein the buffer chamber is an open space that opens at both ends, and one of the buffer chambers opens toward the discharge port, and the opposite opening is in contact with the filter.   4. The ink jet cartridge according to claim 3, wherein the buffer chamber has a cross-sectional area that gradually increases from the opening on the discharge port side toward the center of the buffer chamber.   The ink jet cartridge according to claim 4, wherein ink is held in a narrow space of the discharge port side opening of the buffer chamber.   The discharge port provided in the said filter and the said printing element board | substrate is connected linearly via the said ink flow path, The said filter and discharge port are comprised facing, The Claim 1 characterized by the above-mentioned. Item 6. The inkjet cartridge according to any one of Items 5.

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