JP2009166257A - Inkjet recording head, head cartridge and recording device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To eject inks in various droplet amounts by using the same power source inexpensively in an inkjet recording head having a nozzle for ejecting an ink in relatively large droplet size, and a nozzle for ejecting an ink in relatively small droplet size. <P>SOLUTION: The inkjet recording head is equipped with a voltage applying means which makes voltage applied from one power source different in voltage value between a heater provided in the nozzle for ejecting the ink in large droplet size and a heater provided in the nozzle for ejecting the ink in small droplet size, and applies the voltage to each of them. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an ink jet recording head, a head cartridge, and a recording apparatus that perform recording by causing an arbitrary current to flow through a heater in accordance with a recording signal, foaming ink, and ejecting ink from an ejection port.

  The ink jet recording head is configured to record an image on a recording medium by ejecting ink from a plurality of fine ejection openings according to a recording signal, and can perform non-contact recording on a recording medium such as recording paper. There are advantages such as being easy to make and quiet.

  Here, an ink jet recording head that performs recording using thermal energy will be described as an example.

  Ink jet recording heads are provided with ejection openings and corresponding heaters, and when current is applied to the heaters, the ink is heated and foamed. Then, the ink is ejected from the ejection port by the energy generated by the foaming to form an image. Such an ink jet recording head can arrange heaters at high density. Further, it is possible to eject small droplets of ink. For this reason, it is possible to form a high-quality image.

  Currently, a recording apparatus using an ink jet recording head is required to form a high-quality image, and is also required to perform recording at high speed. As one method for achieving both high-quality image formation and high-speed recording, there is a method in which the size of ejected ink droplets is determined according to the recording mode. In the high-speed mode, recording is performed with a large ink droplet at a low resolution, and in the high-quality mode, recording is performed with a small ink droplet at a high resolution. Thus, by providing a plurality of recording modes, it is possible to achieve both high-quality image formation and high-speed recording. Also, by recording using both large ink droplets and small ink droplets, an image having high gradation can be formed at high speed. As described above, it is possible to obtain a great effect that the user can record with desired image quality by selecting an optimum recording mode.

As an ink jet recording head for simultaneously forming such a high quality image and recording at a high speed, there is an ink jet recording head disclosed in Patent Document 1. This is a configuration in which first and second heaters having relatively different ink discharge amounts are alternately arranged in a nozzle row including a plurality of nozzles each provided with a heater corresponding to each discharge port. Inkjet recording head. Then, one of the first and second heaters is driven in accordance with the select signal to form an image with high gradation characteristics at high speed. In addition, since the first and second heaters having relatively different ink discharge amounts (different sizes) are driven by the same power source, the power supply wiring can be shared, so that the circuit configuration is simplified and reduced. Cost and size can be reduced.
JP 2004-122757 A

  In recent years, ink jet recording heads equipped with one heater corresponding to each ejection port have made smaller droplets of ink to be ejected, enabling image formation with higher image quality and higher gradation than before. It has become to. As described above, recording with large ink droplets and small ink droplets enables high-quality images with high gradation to be recorded at high speed. However, due to the recent reduction in droplets of ink to be ejected, the difference in the amount of droplets between large ink and small ink is increasing. In order to express a higher gradation, it is required to eject ink with various droplet amounts in order to fill the difference between the droplet amounts of the large ink and the small ink. In order to eject various amounts of ink, various foaming energies are required depending on the amount of ink ejected, which may increase the power supply, complicate the circuit configuration, and increase costs. is there.

  In order to eject ink with various droplet amounts at low cost, the heater material used and the film pressure are the same in the heater that ejects ink with different droplet amounts, and the circuit configuration is not significantly changed from the conventional one. It is desirable not to increase the number of power supplies. Moreover, it is difficult to assign a plurality of power supplies to one nozzle row from the viewpoint of the layout efficiency of the power supply wiring. For this reason, it is desirable to record a high-quality image by ejecting a plurality of different appropriate amounts of ink from one nozzle row using one power source.

  However, as described above, various foaming energies are required to eject ink with various droplet amounts. As a method for driving heaters that discharge different amounts of ink with the same power source, conventionally, the heaters are made rectangular, the resistance value is adjusted, the pulse width of the current flowing through the heater is adjusted, and so on. It was. In general, the largest energy required for ejection is a nozzle that ejects large droplets of ink. For this reason, the power supply voltage is set based on the voltage for ejecting large droplets of ink, and for the nozzles that eject medium and small droplets of ink, the energy for foaming the ink is adjusted using the above two methods. To do.

  In the first method of changing the shape of the heater, it is possible to change the resistance value by making the heater rectangular, adjust the current value flowing through the heater, calculate the threshold value at which the ink foams, and adjust the energy. .

  FIG. 7 shows an example of the vicinity of a heater of an ink jet recording head provided with a rectangular heater.

  Conventionally, the resistance of the heater can be set higher than that of the square heater by making the shape of the heater, which is generally square, rectangular as shown by 701 in FIG. Thus, the energy applied to the ink can be adjusted by changing the shape of the heater. By adjusting the energy applied to the ink in this way, it is possible to eject large droplet ink and small droplet ink using the same power source.

  However, such a rectangular heater 701 is subject to size restrictions, and is also subject to driving restrictions and restrictions due to the resistance value of the heater film. In addition, there is a problem that the influence of a change in the discharge direction due to the positional deviation from the discharge port 702 is larger than that of the square heater.

  On the other hand, as in the second method, the same power source is controlled by adjusting the pulse widths of the currents flowing to the heater for ejecting small droplet ink and the heater for ejecting large droplet ink. There is a method of discharging large droplet ink and small droplet ink. For example, a square heater smaller than a square heater for ejecting large droplets of ink is used as a heater for ejecting small droplets of ink. Then, the pulse width of the current flowing through the heater for discharging the small droplet ink is made shorter than the pulse width of the current flowing through the heater for discharging the large droplet ink.

  However, if the pulse width is gradually shortened, the ink foams before the heat of the heater is transmitted to the entire ink in the liquid chamber from a certain pulse width. If the ink is foamed in a state where heat is not sufficiently transferred to the ink in the liquid chamber, the bubbles are very small and it becomes difficult to eject the ink. In this way, the width of the current pulse that flows through the heater also has a balance with the size of the bubbles due to the foaming of the ink, and the adjustable range is limited.

  As described above, there are many problems in ejecting ink with various droplet amounts using the same power source. In particular, the recent trend toward smaller droplets of ejected ink has led to an increase in the difference between the size of large droplet ink and the size of small droplet ink, which is necessary for ejecting ink. The energy gap is also increasing. For this reason, it has become difficult to eject ink with various droplet amounts using the same power source by the above method.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an ink jet recording head, a head cartridge, and a recording apparatus that can eject ink of various droplet amounts using the same power source at low cost.

The present invention for solving the above problems has a nozzle for ejecting a relatively large size ink and a nozzle for ejecting a relatively small size ink, and heat energy is provided by a heater provided in each nozzle. An ink jet recording head that discharges ink by applying to the ink,
The voltage applied from one power supply is varied between the heaters provided in the nozzles that eject the large size ink and the heaters provided in the nozzles that eject the small size ink. It is characterized by comprising an applying means for applying to.

  Another aspect of the present invention for solving the above problems is a head cartridge and a recording apparatus having the ink jet recording head.

  According to the present invention, it is possible to eject ink with various droplet amounts using the same power source at low cost without greatly changing the circuit configuration from the conventional one.

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

  In this specification, “recording” (hereinafter also referred to as “printing”) is not only for forming significant information such as characters and figures, but also for images on a wide range of recording media, regardless of significance. A case where a pattern, a pattern, or the like is formed or a medium is processed is also expressed. It does not matter whether it has been made obvious so that humans can perceive it visually.

  “Recording medium” refers not only to paper used in general recording apparatuses but also widely to cloth, plastic film, metal plate, glass, ceramics, wood, leather, and the like that can accept ink. Shall.

  The term “ink” should be broadly interpreted in the same way as the definition of “recording”. When applied to a recording medium, the “ink” forms an image, a pattern, a pattern, or the like, or processes the recording medium. It represents a liquid that can be subjected to the treatment. Examples of the ink treatment include solidification or insolubilization of the colorant in the ink applied to the recording medium.

  Furthermore, unless otherwise specified, the “nozzle” collectively refers to an ejection port, a liquid path communicating with the ejection port, and an element that generates energy used for ink ejection.

Example 1
FIG. 8 is an external perspective view showing an outline of the configuration of an ink jet recording apparatus which is a typical embodiment of the present invention.

  As shown in FIG. 8, an ink jet recording apparatus (hereinafter referred to as a recording apparatus) includes a recording head 3 that performs recording by discharging ink in accordance with an ink jet system. The driving force generated by the carriage motor M1 is transmitted from the transmission mechanism 4 to the carriage 2 on which the recording head 3 is mounted, and the carriage 2 is reciprocated (reciprocated scanning) in the direction of arrow A which is the main scanning direction. Along with this reciprocal scanning, for example, a recording medium P such as recording paper is fed through a paper feeding mechanism 5 and conveyed to a recording position, and from the ink jet recording head (hereinafter also simply referred to as a recording head) 3 at the recording position. Recording is performed by ejecting ink onto the recording medium P.

  In addition to mounting the recording head 3 on the carriage 2 of the recording apparatus, an ink tank 6 for storing ink to be supplied to the recording head 3 is mounted. The ink tank 6 can be attached to and detached from the carriage 2.

  The recording apparatus shown in FIG. 8 is capable of color recording. For this reason, the carriage 2 has four ink tanks containing magenta (M), cyan (C), yellow (Y), and black (K) inks, respectively. It is installed. These four ink tanks can be attached and detached independently.

  The carriage 2 and the recording head 3 can achieve and maintain a required electrical connection by properly contacting the joint surfaces of both members. The recording head 3 applies energy according to a recording signal to selectively eject ink from a plurality of ejection ports for recording. In particular, the recording head 3 of the present embodiment employs an ink jet system that ejects ink using thermal energy, and includes a heater for generating thermal energy. Electric energy applied to the heater is converted into thermal energy, and ink is ejected from the ejection port by utilizing pressure changes caused by bubble growth and contraction caused by film boiling caused by applying the thermal energy to the ink. . This heater is provided corresponding to each of the ejection ports, and ejects ink from the corresponding ejection port by applying a pulse voltage to the corresponding heater according to the recording signal.

  As shown in FIG. 8, the carriage 2 is connected to a part of the driving belt 7 of the transmission mechanism 4 that transmits the driving force of the carriage motor M <b> 1, and slides in the direction of arrow A along the guide shaft 13. It is guided and supported freely. Accordingly, the carriage 2 scans back and forth along the guide shaft 13 by forward and reverse rotations of the carriage motor M1. Further, a scale 8 is provided for indicating the position of the carriage 2 along the main scanning direction (arrow A direction) of the carriage 2.

  Further, the recording apparatus is provided with a platen (not shown) facing the discharge port surface where the discharge port (not shown) of the recording head 3 is formed, and the recording head 3 is driven by the driving force of the carriage motor M1. The mounted carriage 2 is scanned back and forth. At the same time, recording is performed over the entire width of the recording medium P conveyed on the platen by supplying a recording signal to the recording head 3 and discharging ink.

  The recording apparatus is provided with a recovery device 10 for recovering a discharge failure of the recording head 3 at a position outside the range of reciprocating motion (outside the recording area) for the recording operation of the carriage 2 on which the recording head 3 is mounted. Has been.

  The recovery device 10 includes a capping mechanism 11 that caps the ejection port surface of the recording head 3 and a wiping mechanism 12 that cleans the ejection port surface of the recording head 3. Then, in conjunction with the capping of the ejection port surface by the capping mechanism 11, ink is forcibly discharged from the ejection port by a suction means (a suction pump or the like) in the recovery device. As a result, an ejection recovery operation such as removing ink or bubbles with increased viscosity in the ink flow path of the recording head 3 is performed.

  Further, when the recording head 3 is not in operation or the like, the ejection port surface of the recording head 3 is capped by the capping mechanism 11 to protect the recording head 3 and to prevent ink evaporation and drying. On the other hand, the wiping mechanism 12 is disposed in the vicinity of the capping mechanism 11 and wipes ink droplets adhering to the discharge port surface of the recording head 3.

  In addition, the recording apparatus is configured such that preliminary ejection can be performed by ejecting ink not related to recording to the capping mechanism 11.

  The ink discharge state of the recording head 3 can be kept normal by the suction operation and preliminary discharge operation using the capping mechanism 11 and the wiper operation using the wiping mechanism 12.

  FIG. 9 is a block diagram showing a control configuration of the recording apparatus shown in FIG.

  As shown in FIG. 9, the controller 600 has a ROM 602 that stores an MPU 601, a required table, and other fixed data. In addition, a special application integrated circuit (ASIC) 603 that generates control signals for controlling the carriage motor M1, the transport motor M2, and the recording head 3 is provided. The RAM 604 is provided with a development area for image data, a work area for program execution, and the like. In addition, the system bus 605 is connected to the MPU 601, the ASIC 603, and the RAM 604 to exchange data. Furthermore, an A / D converter 606 is provided that converts an analog signal input from a sensor group described below into a digital signal and supplies the digital signal to the MPU 601. In addition, the controller 600 drives the plurality of nozzles at predetermined time intervals during preliminary ejection and recording.

  Reference numeral 610 denotes a computer or the like serving as a supply source of image data, and is collectively referred to as a host. Image data, commands, status signals, and the like are transmitted and received between the host 610 and the recording apparatus via an interface (I / F) 611.

  Further, reference numeral 620 denotes a switch group, which includes a power switch 621, a print switch 622 for instructing the start of printing, and a recovery switch 623 for instructing the start of the recovery operation. Composed. Reference numeral 630 denotes a sensor for detecting an apparatus state including a position sensor 631 such as a photocoupler for detecting a home position, a temperature sensor 632 provided at an appropriate position of the recording apparatus for detecting an environmental temperature, and the like. A group.

  Further, 640 is a carriage motor driver that drives the carriage motor M1, and 642 is a conveyance motor driver that drives the conveyance motor M2.

  Although FIG. 8 shows a configuration in which the ink tank 6 and the recording head 3 are separated, this embodiment may be a head cartridge in which the ink tank and the recording head are integrally formed.

  FIG. 10 is an external perspective view showing the configuration of the head cartridge 100 in which the ink tank 6 and the recording head 3 are integrally formed. In the drawing, a dotted line K indicates a boundary line between the ink tank 6 and the recording head 3. Reference numeral 500 denotes an ink discharge port array in which a plurality of discharge ports are arranged. The ink stored in the ink tank 6 is supplied to the recording head 3 via an ink supply path (not shown). The head cartridge 100 is provided with electrodes (not shown) for receiving an electrical signal supplied from the carriage 2 side when mounted on the carriage 2. Then, the recording head 3 is driven by this electric signal, and ink is selectively ejected from each ejection port of the ejection port array 500.

  FIG. 1 is a view showing an ink jet recording head which is a typical embodiment of the present invention.

  The recording head includes ejection openings that eject inks of relatively large, medium, and small sizes. In addition, as shown in FIG. 1, the basic structure of this recording head is such that six ink supply ports are provided on a single element substrate, cyan ink at ink supply ports A and F, and magenta ink at B and E. , C is supplied with black ink, and D is supplied with yellow ink. A large droplet discharge port a for discharging a large droplet of ink to each ink supply port, a medium droplet discharge port b for discharging a medium droplet of ink, and a small droplet of ink are discharged. And a small droplet discharge port c. Further, the medium droplet ejection port b and the small droplet ejection port c are provided on the same side with respect to the ink supply port, and are alternately arranged in a staggered manner.

  FIG. 2 is an enlarged view of the ink supply port and the discharge port of the recording head of FIG.

  A large droplet discharge port a1 and a large droplet discharge heater a2 are provided on one side of each ink supply port, and a medium droplet discharge port b1, a medium droplet discharge heater b2, and a small liquid are provided on the other side. A droplet discharge port c1 and a small droplet discharge heater c2 are provided. Ink is supplied from an ink supply port to the heater and the discharge port via an ink flow path. Each ink flow path is partitioned by a partition wall 101.

  FIG. 3 is a diagram showing a circuit layout of the recording head of this embodiment.

  As shown in FIG. 3, both ends of each heater are connected by aluminum wiring (Al wiring), one is a VH wiring 301 connected to the power source of the current flowing through the heater, and the other is a lower driver transistor through a through hole 302. 303 is connected to the drain. Although not shown in FIG. 3, the VH wiring 301 is connected to a thick VH wiring provided in the upper layer of the driver transistor 303, and the source of the driver transistor 303 passes through the upper Al wiring through the through hole 304. Connected to the ground. A current flows from the VH wiring 301 to the heater according to the heater drive control performed by turning on or off the driver transistor, the heater is heated, ink is foamed, and ink is ejected from the nozzle.

  One large droplet discharge heater 305 uses one VH wiring, and two medium droplet heaters 306 and small droplet heater 307 use a common VH wiring. Thus, by using the VH wiring in common, the heaters can be arranged at a higher density, leading to higher image quality.

  FIG. 4 is a circuit diagram of the recording head of this embodiment.

  FIG. 4A is a diagram showing a heater for small droplets and a heater for medium droplets and driver transistors connected to them, and FIG. 4B is a heater for large droplets and drivers connected thereto. It is a figure which shows a transistor etc. As shown in FIGS. 4A and 4B, when the number of gates of the driver transistor (MOSFET) 401 connected to the small droplet heater is two, the driver transistor (MOSFET) 401 is connected to the medium droplet heater. The total number of driver transistors is four. Further, the total number of gates of driver transistors connected to the large droplet heater is six.

  As described above, the on-resistance of the driver transistor is changed by changing the number of gates of the driver transistor in accordance with the size of the ejected ink droplet. A large droplet heater that requires a large amount of energy to eject ink causes a large number of currents to flow by setting the number of driver transistor gates to be connected to 6 so that the ON resistance is set low. On the contrary, in the small liquid application heater, the number of driver transistors to be connected is set to two to increase the on-resistance, thereby suppressing the current flowing through the heater and reducing the energy.

  Thus, the on-resistance of the driver transistor is changed by changing the number of gates. With such a configuration, the current flowing through the heater can be adjusted, and the energy applied to the ink by the heater can be controlled according to the size of the ejected ink. For this reason, it is possible to eject ink with various droplet amounts using the same power supply, and the circuit can be manufactured at a lower cost compared to a recording head having a configuration using different power supplies according to the conventional ejection amount. A recording head having a simple configuration can be obtained.

  FIG. 5 is a diagram showing a circuit layout of the driver transistor.

  In this embodiment, the heater driving method disclosed in Japanese Patent Laid-Open No. 9-327914 is used, and M × N heaters arranged in a row are divided into N blocks each by M. Divided drive. By arranging M groups of adjacent N heaters that are not driven at the same time, heater rows arranged in a row are formed. In the driver transistor layout shown in FIG. 5, driver transistors for driving N heaters share all the sources 501 and are arranged with high area efficiency.

  In the conventional recording head, the number of gates of driver transistors connected to the heaters arranged in one row is equal. For example, when a driver transistor having two gates is used, drain A, drain B, and drain C in FIG. 5 are independently connected to one heater, and each gate A, gate B, gate C Are also connected to the logic circuit independently.

  In contrast, in the recording head of this embodiment, the number of gates of the driver transistors can be adjusted while maintaining the layout configuration of the conventional driver transistors. In the recording head configured as shown in FIG. 4A, the drain A is connected to a small droplet heater. Further, the drain B and the drain C are connected and connected to one medium droplet heater, and the gate B and the gate C are connected and connected to the logic circuit. By repeating such a pattern, it is possible to adjust the number of gates of the driver transistors in the heater array composed of the small droplet heater and the medium droplet heater. 4B, the drain A, the drain B, and the drain C are connected to one large droplet heater, and the gate A, the gate B, and the gate C are connected. Connect to the logic circuit. By repeating such a pattern, it is possible to adjust the number of gates of driver transistors in a heater array composed of large droplet heaters.

  Similarly, by connecting by changing the ratio of the number of gates, it is composed of a heater array composed of heaters for large droplets, medium droplets and small droplets, and heaters for large droplets and small droplets. In the heater array, the number of gates of the driver transistors can be adjusted.

  The wiring is rearranged as described above, and the current flowing through the heater is adjusted by changing the ratio of the number of gates (the voltage value applied to the heater is adjusted). This makes it possible to control the energy that the heater gives to the ink without greatly changing the circuit layout from the conventional circuit layout. Accordingly, it is possible to discharge ink with various droplet amounts using one power source, and it is possible to form a high-quality image at low cost.

  Compared with the method of adjusting the ink droplet volume by adjusting the pulse width and changing the heater shape using the same power supply, the circuit design becomes easier and the range of droplet volume that can be discharged Can be set widely. By changing the ratio of the number of gates, it becomes possible to easily arrange heaters with different amounts of ink ejected in various patterns, and in response to various requirements for high-speed and high-quality image formation. It is possible to respond flexibly.

  On the other hand, there is a method in which the on-resistance value of the driver transistor is adjusted not by the ratio of the number of gates but by the L length (channel length) of the gate. If this method and the method of changing the ratio of the number of gates are performed at the same time, the range of resistance adjustment is further widened, and the size difference between the large droplet and the small droplet can be further increased. In addition, since it is possible to finely adjust an appropriate amount of ink to be ejected, it is possible to eject inks of various types of droplets.

(Example 2)
In the first embodiment, the current flowing through the heater is adjusted by changing the on-resistance of the driver transistor by adjusting the number of gates and the L length of the gate. In this embodiment, the on-resistance of the driver transistor is not changed, but the current flowing through the heater is adjusted by arranging a resistance element in the wiring connecting the driver transistor and the heater.

  FIG. 6A is a circuit layout of the recording head of this embodiment, and FIG. 6B is a circuit diagram thereof.

  As shown in FIG. 6A and FIG. 6B, in the recording head of this embodiment, the medium liquid application heater is directly connected to the driver transistor, and the small liquid application heater includes the driver transistor and the resistance element 61. Connected through. The resistance element 61 shown in FIGS. 6A and 6B uses an element having the same configuration as the small droplet heater and the medium liquid application heater. The resistance value of the resistance element 61 can be adjusted by changing its shape. When a current flows through the small droplet heater, a current also flows through the resistance element 61, so that the resistance element 61 also generates heat. For this reason, if the resistance element 61 is disposed in a portion in contact with the ink, it is expected that the ink is heated or the ink is foamed, which may affect the ejection of the ink. For this reason, it is desirable that the arrangement position of the resistance element 61 is inside the partition wall.

  In FIGS. 6A and 6B, the resistance element is arranged on the driver transistor side with reference to the heater, but may be arranged on the VH wiring side. Moreover, although the element similar to a heater was used as a resistive element, you may use other resistive elements, for example, a diffused resistance and a POLY-Si resistance. Further, instead of arranging such a resistance element, the resistance value of this portion may be increased by drawing the aluminum wiring thinly and long.

  In FIGS. 6A and 6B, the resistance elements are provided only for the wiring of the small liquid application heater. However, the resistance elements having different resistance values may be provided for the wiring of the medium liquid application heater. Thus, by further combining a large liquid application heater, it is possible to have a configuration capable of ejecting ink suitable for large liquid, suitable for medium liquid, and suitable for small liquid.

  Further, if the adjustment of the current flowing through the heater by adjusting the on-resistance of the driver transistor shown in the first embodiment is performed in combination, it is possible to adjust the liquid amount of ink to be ejected more finely. A drop amount of ink can be ejected.

1 is a diagram showing an ink jet recording head that is a typical embodiment of the present invention. FIG. FIG. 2 is an enlarged view of an ink supply port and an ejection port of the recording head in FIG. 1. FIG. 3 is a diagram illustrating a circuit layout of the recording head of Example 1. FIG. 3 is a circuit diagram of the recording head of Example 1. It is a figure which shows the circuit layout of a driver transistor. FIG. 6 is a diagram and a circuit diagram illustrating a circuit layout of a recording head of Example 2. It is a figure which shows the example of the heater vicinity part of the inkjet recording head provided with the conventional rectangular heater. 1 is an external perspective view showing an outline of a configuration of an ink jet recording apparatus that is a typical embodiment of the present invention. 3 is a block diagram illustrating a configuration of a control circuit of the recording apparatus. FIG. FIG. 3 is an external perspective view illustrating a configuration of a head cartridge in which an ink tank and a recording head are integrally formed.

Explanation of symbols

61 Resistance element 303 Driver transistor 401 Driver transistor a1 Large droplet discharge port a2 Large liquid application heater b1 Medium droplet discharge port b2 Medium liquid application heater c1 Small droplet discharge port c2 Small liquid application heater

Claims (9)

An ink jet having a nozzle for ejecting a relatively large size ink and a nozzle for ejecting a relatively small size ink, and applying the thermal energy to the ink by a heater provided in each nozzle. A recording head,
The voltage applied from one power supply is varied between the heaters provided in the nozzles that eject the large size ink and the heaters provided in the nozzles that eject the small size ink. An ink jet recording head comprising an applying means for applying to the ink jet recording head.   The ink jet recording head according to claim 1, wherein the applying unit includes a driver transistor. The driver transistor is a MOSFET,
The number of gates of the MOSFET connected to the heater provided in the nozzle for discharging the large size ink and the MOSFET connected to the heater provided in the nozzle for discharging the small size ink are different. Item 3. The ink jet recording head according to Item 2. The driver transistor is a MOSFET,
The channel length of the MOSFET connected to the heater provided in the nozzle for discharging the large size ink and the MOSFET connected to the heater provided in the nozzle for discharging the small size ink are different. The ink jet recording head according to claim 2.   The ink jet recording head according to claim 1, wherein the applying unit includes a driver transistor and a resistance element.   A heater provided in the nozzle that discharges the large size ink is directly connected to the driver transistor, and a heater provided in the nozzle that discharges the small size ink is connected to the driver transistor via the resistance element. The ink jet recording head according to claim 5.   7. The nozzle according to any one of claims 1 to 6, wherein the nozzles that eject the relatively large size ink and the nozzles that eject the relatively small size ink are alternately arranged in a line. 2. An ink jet recording head according to item 1.   A head cartridge comprising: the ink jet recording head according to claim 1; and an ink tank containing ink. A recording apparatus comprising the recording head according to any one of claims 1 to 7 or the head cartridge according to claim 8, and a power source.
The recording apparatus according to claim 1, wherein a voltage is applied to the applying unit from a power source of the recording apparatus.

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