JP4402101B2 - Inkjet recording head - Google Patents

Description

  The present invention relates to an ink jet recording head having inspection terminals.

  Patent Document 1 describes an ink jet recording head having an inspection terminal.

  The inspection terminal is formed on the substrate together with an energy generation element that generates energy for ejecting ink as a recording liquid, a drive circuit that drives the energy generation element, and an electrical connection terminal that is connected to a power source. Yes. The inspection terminal is electrically connected to the energy generating element, the drive circuit, and the electrical connection terminal. The inspection terminal is used for inspecting the characteristics of the energy generating element, the drive circuit, and the electrical connection terminal.

  Note that dummy inspection terminals are also formed in the ink jet recording head described in Patent Document 1.

  A nozzle forming member is laminated on a substrate on which an energy generating element, an inspection terminal and the like are formed. In the nozzle forming member, an ejection port for ejecting ink is provided at a position corresponding to the energy generating element, and further, a liquid path for supplying ink to the energy generating element is provided.

  FIG. 7 is a circuit diagram showing the wiring of the inspection terminals.

  In FIG. 7, during printing, a current flows from the power supply electrical connection terminal 101 to the GND electrical connection terminal 102 via the resistor 100a, the energy generating element 103, the drive circuit 104, and the resistor 100b. The energy generating element 103 generates heat when an electric current flows, and the heat causes the ink to be heated and foamed to be discharged from the discharge port. On the other hand, when measuring the resistance value of the drive circuit 104, the resistance value between the test terminals 105A and 105B is measured. Hereinafter, the inspection terminals 105A and 105B are collectively referred to as the inspection terminal 105.

If ink adheres to the inspection terminal 105, the inspection terminal 105 may corrode and the ink jet recording head may be broken. Therefore, the inspection terminal 105 is plated with gold so as not to come into contact with ink or the like and is covered with a nozzle forming member.
Japanese Unexamined Patent Publication No. 7-323549

  However, the conventional techniques have the following problems.

  Stress may be applied between the substrate which is a different material and the nozzle forming member due to heating performed in the head manufacturing.

  FIG. 8A is a schematic diagram showing the substrate 106 on which the inspection terminal 105 is formed and the nozzle forming member 107 laminated on the substrate 106. FIG. 8B is an enlarged schematic perspective view of a portion A in FIG. In FIG. 8, the nozzle forming member 107 is provided with a plurality of discharge ports 108, and the same components as those shown in FIG.

  Stress tends to concentrate on the outer peripheral portion of the substrate 106 on which the inspection terminals 105 and the like are formed. For this reason, as shown in FIG. 8, a peeling portion 109 where the substrate 106 and the nozzle forming member 107 are peeled off may occur.

  When the nozzle forming member 107 is peeled from the substrate 106, the ink may contact the inspection terminal 105 after the head is completed.

  FIG. 9A is a schematic diagram illustrating a state where the ink 110 is not in contact with the inspection terminal 105. FIG. 9B is a schematic diagram illustrating a state where the ink 110 is in contact with the inspection terminal 105. In FIG. 9, the same components as those shown in FIG.

  Usually, since the inspection terminal 105 is covered with gold plating, it does not corrode only by the ink 110 coming into contact therewith.

  However, when the nozzle forming member 107 is peeled off from the substrate 106, the ink 110 is likely to penetrate due to the meniscus force acting between the peeling portion 109 and the substrate 106, and as shown in FIG. In many cases, the ink 110 is present across the boundary 105B.

  The inspection terminal 105 </ b> A is connected to the energy generating element 103 and the power supply electrical connection terminal 101. For this reason, when a voltage is applied to the power supply electrical connection terminal 101, a voltage is also applied to the inspection terminal 105A.

  Therefore, when a voltage is applied to the power supply electrical connection terminal 101 in the state shown in FIG. 9B, a current flows between the inspection terminals 105 </ b> A and 105 </ b> B through the ink 110. Thereby, the electrolysis of the gold plating formed on the inspection terminal 105 gradually occurs, and the inspection terminal 105 is exposed by dissolving the gold coating. For this reason, there is a problem that the inspection terminal 105 is corroded and eventually the corrosion proceeds to the head driving portion, and the ink jet recording head is not operated.

  This problem occurs when a driving current flows between the inspection terminals 105 </ b> A and 105 </ b> B through the ink 110, so that the inspection terminal 105 may occur even in an ink jet recording head that is not originally covered with the nozzle forming member 107. There is.

  An object of the present invention is to provide an ink jet recording head capable of suppressing corrosion of an inspection terminal.

To solve the above problems, an ink jet print head of the present invention includes a plurality of drive circuits for controlling a plurality of energy generating elements for generating energy for ejecting recording liquid, a plurality of energy generating elements, said energy generating element And an electric connection terminal for receiving an electric signal for driving the driving circuit, an operation circuit unit including a plated inspection terminal for inspecting the operation circuit unit, and each of the plurality of energy generating elements In the inkjet recording head having a plurality of discharge ports and a plurality of liquid paths communicating with each of the plurality of discharge ports, a control element is provided between the operation circuit unit and the inspection terminal. When the electrical signal is input to the electrical connection terminal, the control element includes the operation circuit unit and the inspection terminal. Door to electrically disconnect the.

  According to the present invention, it is possible to suppress corrosion of the inspection terminal in the ink jet recording head.

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

  The ink jet recording head of the present embodiment performs recording by ejecting liquid and forming flying droplets, and is applied to a liquid ejection head. This liquid discharge head is a printer, a copying machine, a facsimile having a communication system, a word processor having a printer unit, etc. for recording on a recording medium, and an industrial recording device combined with various processing devices. Used for. As the recording medium, for example, paper, thread, fiber, fabric, leather, metal, plastic, glass, wood, or ceramic is used.

  Note that “recording” means not only giving an image having a meaning such as a character or a figure to a recording medium but also giving an image having no meaning such as a pattern.

(First embodiment)
FIG. 1 is a schematic diagram illustrating a substrate included in the ink jet recording head according to the first embodiment of the present invention.

  In FIG. 1, a substrate 1 includes a plurality of energy generating elements 2, a plurality of driver units 3, a plurality of logic circuit units 4, a plurality of electrical connection terminals 5, a plurality of test terminals 6, and a plurality of test terminals. A control element 7 is formed.

  The substrate 1 is formed in a substantially rectangular shape using a semiconductor manufacturing technique on a silicon semiconductor substrate or the like. In the central portion of the substrate 1, an ink supply port 20 which is a through hole extending in the longitudinal direction is formed.

  The plurality of energy generating elements 2 are provided along both sides of the ink supply port 20. The energy generating element 2 generates energy for ejecting ink droplets that are recording liquid.

  The driver unit 3 and the logic circuit unit 4 constitute a drive circuit for controlling the driving of the energy generating element 2.

  The driver unit 3 includes a driver for driving each energy generating element 2. The driver is typically provided for each energy generating element 2 and includes a switching transistor or the like. The driver unit 3 is provided on both sides of the ink supply port 20 and outside the energy generating element 2.

  The logic circuit unit 4 and the electrical connection terminal 5 are provided on both sides of the short end of the ink supply port 20.

  Each electrical connection terminal 5 is electrically connected to the ink jet recording apparatus by using electrical connection means such as wire bonding. Each electrical connection terminal 5 is a control signal that receives a power supply electrical connection terminal that receives a drive voltage, a GND electrical connection terminal that is connected to GND, and a control signal that controls on / off of each transistor in the driver unit 3. It is classified as one of the electrical connection terminals. The drive voltage is an example of an electrical signal that drives the energy generating element 2 and the drive circuit.

  When the logic circuit unit 4 receives a control signal from the main body of the inkjet recording apparatus via the control signal electrical connection terminal, the logic circuit unit 4 controls on / off of each transistor in the driver unit 3 based on the control signal.

  The inspection terminal 6 is used for inspecting the driving characteristics of the energy generating element 2, the driver unit 3, the logic circuit unit 4, and the electrical connection terminal 5, for example. The inspection terminal 6 is plated with gold, platinum, palladium, iridium, or an alloy thereof.

  The control element 7 controls the direction of current flowing between the electrical connection terminal 5 and the inspection terminal 6.

  A nozzle forming member is laminated on the substrate 1. In this embodiment, the inspection terminal 6 is covered with a nozzle forming member.

  FIG. 2 is a schematic view showing the substrate 1 on which the nozzle forming member 8 is laminated.

  In FIG. 2, a plurality of discharge ports 9 and a plurality of liquid paths 10 are formed in the nozzle forming member 8. The discharge port 9 and the liquid path 10 are formed using a photolithography process.

  Each discharge port 9 corresponds to each of the plurality of energy generating elements 2. The plurality of liquid passages 10 communicate with each of the plurality of ejection ports 9, and supply the ink supplied from the ink supply ports 20 to each energy generating element 2 corresponding to each ejection port 9.

  FIG. 3 is a schematic perspective view showing an ink jet recording head using the substrate 1 on which the nozzle forming member 8 is laminated.

  In FIG. 3, the electrical connection terminal 5 of the substrate 1 is connected to a TAB 12 that is an electrical wiring member, and the substrate 1 is joined to the tank forming member 11 with an adhesive to form an ink jet recording head.

  In the ink jet recording head shown in FIG. 3, when a signal is input to the substrate 1 through the electrical connection terminal 5, the logic circuit of the logic circuit unit 4 turns on / off the transistor of the driver unit 3, that is, the driver. The energy generating element 2 connected to the turned-on transistor generates heat when energized, the ink on the energy generating element 2 is heated, and bubbles are rapidly generated in the ink, so that the ink is blown from the discharge port 9. It is.

  FIG. 4 is a schematic diagram showing the energy generating element 2, the electrical connection terminal 5, the inspection terminal 6, the control element 7, and a part of the drive circuit (specifically, the transistor of the driver unit 3) 3a. FIG. The energy generating element 2, the electrical connection terminal 5, and the drive circuit 3a constitute an operation circuit unit 14. In FIG. 4, the control element 7 controls the direction of the current flowing between the operation circuit unit 14 and the inspection terminal 6.

  Further, FIG. 5 is a schematic diagram showing a configuration in which a pMOS transistor is used as a control element and no current flows from the operation circuit unit 14 to the test terminal 6 when a voltage is applied to the gate of the pMOS transistor 7a. It is a circuit diagram. In FIG. 5, the same components as those shown in FIG.

  Further, in FIG. 5, an inverter 15 is provided in front of the gate of the pMOS transistor 7a to control the on / off of the pMOS transistor 7a.

  In FIG. 5, the pMOS transistor 7a is formed during a semiconductor process (not shown) in forming the energy generating element 2 and the like of the substrate 1. The drain of the pMOS transistor 7a is connected to the operation circuit section 14, its source is connected to the inspection terminal 6, and a CMOS inverter 15 is formed at its gate.

  When a voltage is input to the terminal Vin, the nMOS portion 15a of the CMOS inverter 15 operates, no voltage is applied to the gate of the pMOS transistor 7a, and the pMOS transistor 7a is turned on. Therefore, the inspection terminal 6 and the operation circuit unit 14 are electrically connected.

  On the other hand, when no voltage is input to the terminal Vin, the pMOS section 15b of the CMOS inverter 15 operates and the drive voltage Vdd is applied to the gate of the pMOS transistor 7a, so that the pMOS transistor 7a is turned off. Therefore, the inspection terminal 6 is electrically disconnected from the operation circuit unit 14 and, for example, no current flows from the operation circuit unit 14 toward the inspection terminal 6.

  Therefore, when the inspection terminal 6 is used at the time of inspection, a voltage is input to the terminal Vin, whereby the pMOS transistor 7a is turned on, and a current flows from the inspection terminal 6 to the operation circuit unit 14.

  On the other hand, at the time of printing, the voltage at the terminal Vin is released, so that the pMOS transistor 7a is turned off, and no current flows from the operation circuit unit 14 to the inspection terminal 6.

  The inspection terminal 6 includes a terminal used as an input side like the inspection terminal 105A in FIG. 7 and a terminal used as an output side like the inspection terminal 105B in FIG.

  When a pMOS transistor is used as the control element 7 and ON / OFF of the pMOS transistor is controlled by a CMOS inverter or the like, the inspection terminal 6 flows to the inspection terminal 6 with the same configuration regardless of whether the inspection terminal 6 is input or output. It becomes possible to stop the current. For this reason, corrosion of the inspection terminal 6 can be prevented.

  In the inkjet recording head according to the first embodiment, the applicant forcibly contacts the ink on the inspection terminal 6 and uses the acceleration evaluation assuming that the ink is used under the general consumer. The terminal 6 part was confirmed. As a result, since no current flows through the inspection terminal 6, the inspection terminal 6 was not corroded.

  Further, in order to keep the nozzle forming member 8 covering the inspection terminal 6 even if the nozzle forming member 8 is peeled off from the substrate 1 at the outer peripheral portion of the substrate 1, the substrate is formed outside the portion where the inspection terminal 6 is formed. 1 and the nozzle forming member 8 need to be provided with an extra portion to be separated. Therefore, it is not preferable because the configuration is increased in size and cost.

  In the present embodiment, by arranging the control element 7 between the operation circuit portion 14 and the inspection terminal 6, even if the substrate 1 and the nozzle forming member 8 are separated, a current flows through the inspection terminal 6. Therefore, corrosion of the inspection terminal 6 can be prevented without increasing the size of the substrate 1. Further, even if the plated inspection terminal 6 is not originally covered with the nozzle forming member 8, the plating of the inspection terminal 6 becomes difficult to be electrolyzed, so that corrosion of the inspection terminal 6 can be prevented. .

  According to the present embodiment, the control element 7 controls the direction of the current flowing between the operation circuit unit 14 and the inspection terminal 6. Therefore, when an electrical signal for driving is input to the electrical connection terminal 5, the current is prevented from flowing from the operation circuit unit 14 to the inspection terminal 6, thereby plating the inspection terminal 6 in contact with the ink. It becomes possible to prevent electrolysis of the. For this reason, corrosion of the inspection terminal 6 can be prevented, and the reliability of the head can be improved.

  In the present embodiment, the operation circuit portion 14 and the inspection terminal 6 are provided on the substrate 1, the discharge port 9 and the liquid path 10 are provided on the nozzle forming member 8, and the inspection terminal 6 is formed by the nozzle forming member 8. Covered.

  In this case, when the nozzle forming member 8 is peeled off from the portion of the substrate 1 on which the inspection terminal 6 is formed, the ink is subjected to a plurality of inspection terminals 6 by a meniscus force acting between the peeling portion of the nozzle forming member 8 and the substrate 1. The more you touch. However, the control element 7 prevents the current from flowing from the operation circuit unit 14 to the inspection terminal 6 when a driving electrical signal is input to the electrical connection terminal 5, so that the inspection terminal contacted with the ink can be obtained. It is possible to prevent electrolysis of the plating 6.

  In the present embodiment, a MOS transistor 7 a is used as the control element 7. In this case, the electrical connection between the inspection terminal 6 and the operation circuit unit 14 can be appropriately controlled.

(Second Embodiment)
FIG. 6 is a schematic circuit diagram showing a second embodiment of the present invention.

  In the present embodiment, a diode 7b is used as the control element 7 connected to the inspection terminal 6 on the input side such as the inspection terminal 105A of FIG. In this embodiment, other configurations are the same as those in the first embodiment.

  The diode 7b is formed during a semiconductor process (not shown) when forming the energy generating element 2 and the like of the substrate 1 so that the forward voltage direction of the diode 7b is directed from the inspection terminal 6 toward the diode 7b. Is formed. For this reason, even when a voltage is applied to the electrical connection terminal 5, no current flows from the operation circuit unit 14 to the inspection terminal 6.

  The applicant of the present invention uses the inkjet recording head of the second embodiment to force ink to contact the inspection terminal 6 and perform an accelerated evaluation assuming a state where the ink is used under ordinary consumers. Inspection terminal 6 was confirmed. As a result, current did not flow through the inspection terminal 6, and the inspection terminal 6 did not corrode.

  In the first embodiment, a MOS transistor is used as the control element 7. However, in this case, it is necessary to control on / off of the MOS transistor. Therefore, in this case, control associated with the MOS transistor such as an inverter may be required, and the circuit on the substrate becomes complicated.

  In the second embodiment, since a diode is used as the control element 7, a circuit for controlling on / off of the control element 7 can be eliminated, wiring is not complicated, and the inspection terminal 6 is corroded. Can be prevented.

  In the inspection relating to the driving of the ink jet recording head, there are places where it is necessary to pass a current from the operation circuit section 14 to the inspection terminal 6, and it is difficult to use a diode as the control element 7 in such a place. . Therefore, depending on the purpose of the inspection terminal 6, a pMOS transistor, an nMOS transistor, and a diode may be selectively used as the control element 7, and several kinds of control elements 7 may be installed in the substrate 1.

  According to the present embodiment, since a diode is used as the control element 7, the direction of the current flowing between the operation circuit unit 14 and the inspection terminal 6 is controlled by the direction of the voltage applied to the diode. For this reason, an on / off control circuit required when a MOS transistor is used can be eliminated, and the configuration can be simplified.

  In each embodiment described above, the illustrated configuration is merely an example, and the present invention is not limited to the configuration.

  For example, in the first embodiment, an nMOS transistor may be used as the control element 7.

  In the second embodiment, a diode may be used as the control element 7 connected to the inspection terminal 6 on the output side such as the inspection terminal 105B of FIG. In this case, the diode is formed such that the direction of the forward voltage of the diode is the direction from the operation circuit unit 14 toward the diode. Therefore, even when a voltage is applied to the electrical connection terminal 5, no current flows from the operation circuit unit 14 to the inspection terminal 6.

FIG. 3 is a schematic diagram illustrating a substrate included in the ink jet recording head according to the first embodiment of the present invention. It is the schematic diagram which showed the board | substrate 1 with which the nozzle formation member 8 was laminated | stacked. 1 is a schematic perspective view showing an ink jet recording head of a first embodiment. 1 is a schematic circuit diagram illustrating a first embodiment. 1 is a schematic circuit diagram illustrating a first embodiment. It is the typical circuit diagram which showed the 2nd Embodiment of this invention. It is the circuit diagram which showed the wiring of the conventional test | inspection terminal. It is the schematic diagram which showed the conventional board | substrate and the nozzle formation member. It is the circuit diagram which showed the wiring of the conventional test | inspection terminal.

Explanation of symbols

2 Energy generating element 3a Drive circuit 5 Electrical connection terminal 6 Inspection terminal 7 Control element 9 Discharge port 10 Liquid path 14 Operation circuit section

Claims (4)

A plurality of energy generating elements for generating energy for ejecting recording liquid, a plurality of drive circuits for controlling said plurality of energy generating elements, and electrical connections for accepting the electrical signal for driving the energy generating element and the driving circuit An operation circuit unit including
Plated inspection terminals for inspecting the operating circuit section;
A plurality of ejection openings corresponding to each of the plurality of energy generating elements;
In an inkjet recording head having a plurality of liquid passages communicating with each of the plurality of ejection ports,
A control element is provided between the operation circuit unit and the inspection terminal, and when the electrical signal is input to the electrical connection terminal, the control element is connected to the operation circuit unit and the inspection terminal. An ink jet recording head, wherein a terminal is electrically disconnected .   The inkjet recording according to claim 1, comprising: a substrate on which the operation circuit unit and the inspection terminal are provided; and a nozzle forming member that is provided with the discharge port and the liquid path and covers the inspection terminal. head. The control element, Ri Do a MOS transistor having an input terminal,
2. The ink jet recording head according to claim 1 , wherein when no voltage is input to the input terminal, the operation circuit unit and the inspection terminal are electrically disconnected . 4. The ink jet recording head according to claim 1 , wherein the control element conducts the operation circuit unit and the inspection terminal when inspecting the operation circuit unit . 5.

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