JP2008254362A - Inkjet recording head, inkjet recording device, and substrate for recording head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inkjet recording head which is easily manufactured and can detect leakage of ink with high reliability, even in long connection parts or the like. <P>SOLUTION: In the inkjet recording head, a wiring pattern for detecting leakage of ink is provided on a portion of an electric substrate where the leakage of ink is expected to occur, to always detect the leakage of ink when the power is supplied to the inkjet recording device and during operation of the device. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an ink jet recording head that performs ink leak detection in an ink jet recording head that performs recording by discharging ink onto a recording medium, an ink jet recording apparatus, and a substrate for a recording head.

  An ink jet recording apparatus is often used as a recording apparatus having functions such as a printer, a copier, a facsimile, or the like, or a recording apparatus used as an output device such as a composite electronic device including a computer or a word processor. This ink jet recording apparatus performs recording by discharging ink toward a recording medium such as paper, cloth, or plastic sheet based on recording information.

  Such an ink jet recording apparatus is widely used from the viewpoints of low noise, low running cost, easy downsizing of the apparatus, and easy color recording. Among them, a recording head that uses heat as energy used for ejecting ink can realize high-density multi-nozzle relatively easily, and can achieve high resolution and high image quality. In particular, a recording apparatus using a full-line type recording head having a length equivalent to the width dimension of the recording area can record at a higher speed than a serial type recording apparatus that performs recording by reciprocating the recording head. The use as an industrial recording device is expanding.

  In a recording head of an ink jet recording apparatus, a heater board in which a heater for generating heat is built and an electric substrate for supplying electric power to the heater are connected by wire bonding or the like. The connection between the heater board and the electric board is usually sealed with a sealant such as silicon because there is a risk of corrosion or short circuit when touched with ink. However, depending on the usage environment of the recording apparatus, the sealant may deteriorate, and ink may enter from the deteriorated portion. In particular, when ink enters the deteriorated portion of the sealant in the power supply connection portion, the ink is electrolyzed and becomes highly conductive, and a leak current may flow between the electrodes, resulting in a short circuit state.

  In order to prevent the occurrence of such a phenomenon, conventionally, control such as detecting the leakage of ink and shutting off the power supply has been performed. Patent Document 1 discloses a method of attaching leaked ink to a recording medium, a method of detecting by an optical sensor, a method of detecting using a change in resistance value of an electrode, and a method of using distortion of an ink absorber. . Patent Document 2 discloses a method for detecting ink leakage by using an electrode provided on a substrate to reduce the resistance value between the electrodes when ink leakage occurs. Patent Document 3 discloses a method for detecting ink leakage using an energy converter that reacts with liquid. Further, Patent Document 4 discloses a method for detecting ink leakage by installing a dedicated electrode formed of a conductive paste or the like on the periphery of a piezoelectric element on an actuator during the manufacturing process of a recording head. ing.

JP-A-6-340089 JP-A-10-86357 JP 2001-063013 A JP 2004-058633 A

  In the ink jet recording apparatus, particularly in the configuration of a recording head using a long recording head, the heater board is also long. Along with this, the electric board for supplying electric power to the heater becomes long, and the connecting part between the heater board and the electric board connected by wire bonding or the like becomes long.

  The methods disclosed in Patent Documents 1 and 2 and Patent Document 3 are methods for detecting ink leakage at a specific portion, and in connection portions inside the recording head, particularly in all long connection portions such as line heads. It cannot be used to cover ink leakage. In the method of Patent Document 4, an electrode is provided around the piezoelectric element. This electrode is newly provided for detecting ink leakage, and is formed by baking a conductive paste or the like. . In the case of an electrode formed by such a method, the process for forming the electrode must be provided separately, so that the construction period is long and the cost is high. In addition, since there is a step of firing the conductive paste, the influence of heat must be taken into consideration in the design of other parts.

  Since the line head is long in structure, the part sealed with silicon or the like becomes long, and if an unreasonable force is applied to the recording head main body, ink is discharged from the gap between the sealant and the head electrode. It becomes easy to enter. In addition, since the range where the ink leakage detection of the line head is necessary becomes long, a method capable of detecting a wide range of ink leakage is required. From the above points, it has been difficult for the conventional ink leak detection method to cope with the long line head in terms of cost and configuration.

  Accordingly, an object of the present invention is to provide an ink jet recording head, an ink jet recording apparatus, and a substrate for a recording head that can be easily manufactured and can detect ink leakage with high reliability even in a long connection portion. To do.

  Therefore, the inkjet recording head of the present invention includes an electrical substrate inside, and an inkjet recording head having an ejection port capable of ejecting ink, wherein a pair of exposed wiring patterns is formed on the electrical substrate, Ink leakage detection is possible by detecting a resistance value between the pair of patterns that changes due to ink adhering to the pair of wiring patterns.

  Further, the ink jet recording apparatus of the present invention includes a recording means for performing recording by the ink jet recording head, a means for applying a voltage to the pair of wiring patterns of the ink jet recording head, and a voltage to the pair of wiring patterns. Detecting means for detecting an ink leak by reading a current value flowing between the pair of wiring patterns based on a resistance value that changes due to ink adhering between the pair of wiring patterns. Features.

  Further, the inkjet recording head substrate of the present invention is an inkjet recording head substrate used in an inkjet recording head having an ejection port capable of ejecting ink, and a pair of exposed states on the inkjet recording head substrate. An ink leakage can be detected by detecting a resistance value between the pair of patterns formed by wiring patterns and changing due to ink adhering to the pair of wiring patterns. .

  According to the present invention, a pair of wiring patterns provided in an exposed state is provided on the electric substrate, which is formed in the step of forming the wiring on the electric substrate and can detect ink leakage by detecting the resistance value. It was. As a result, it is possible to provide an ink jet recording head that is easy to manufacture and can detect ink leakage with high reliability even in a long connection portion or the like.

The present invention will be described below with reference to the drawings.
FIG. 1 is an external perspective view showing an ink jet recording apparatus to which the present invention can be applied. The recording medium is conveyed from the recording medium supply unit 114 by the conveyance unit 108. At this time, the black (K) head 101, the cyan (C) head 102, the magenta (M) head 103, and the yellow (Y) head 104 (hereinafter collectively referred to as the recording head 100) which are line type recording heads are opposed. The recording medium is transported to the position where the recording is performed. The recording head 100 includes an ejection port capable of ejecting ink. When the recording medium is conveyed to a position facing the recording head, ink is ejected from the ejection port and recording is performed on the recording medium. The operator can know the processing contents and warning contents of the ink jet recording apparatus through the operation panel 107.

  FIG. 2 is a schematic diagram of an ink jet recording apparatus (hereinafter also simply referred to as a recording apparatus) using a recording head 100 to which the present invention can be applied. The recording head 100 is provided in a state where a plurality of recording heads provided over the entire recording width in the recording medium conveyance direction are arranged in parallel, and the recording head 100 is driven to drive the recording head 100. Ink is ejected from the nozzles provided for the recording. The recording head 100 arranges the recording heads of the respective colors in the transport vertical direction of the recording medium 106 in the order of a black (K) head 101, a cyan (C) head 102, a magenta (M) head 103, and a yellow (Y) head 104. Color recording is possible. During the recording operation, the recording head 100 remains stationary, and the recording medium 106 is conveyed by the conveyance roller 105, and recording is performed by discharging ink from each recording head accordingly.

  FIG. 3 is a diagram for explaining a recording method of recording performed using the ink jet recording apparatus. An image 201 expressed in R (red), G (green), and B (blue) colors on the monitor 200 is subjected to color processing by software (driver), and K (black), C (cyan), and M (magenta). ) And Y (yellow). The image data formed in this way is sent to the recording apparatus. The green portion on the monitor 200 is recorded so that ink is ejected from the C (cyan) recording head and the Y (yellow) recording head at a duty value that reproduces the color of the monitor 200 and can be recognized as green. .

FIG. 4 is a diagram showing a transfer path of recording data. The recording data is compressed by a driver 311 such as a computer 313 and sent to the recording apparatus 300 via an interface 312 such as a USB. In the recording apparatus 300, the recording data is stored in the reception memory 305 via the USB controller 303 and the CPU 304 on the control board 301, and then converted in the control circuit 302 configured by an ASIC or the like and stored in the recording memory 306. Written. Thereafter, the recording data is sent from the recording memory 306 to the recording head 100 via the control circuit 302 again. The recording head 100 includes a register for temporarily storing recording data. When receiving recording data for one line, recording preparation is completed, and recording is performed at an appropriate timing as the recording medium is conveyed.
Thus, in recording using a line head, recording data transfer to the recording head is performed in units of recording data for one line.

  FIG. 5 is an exploded view of the recording head 100 mounted on the ink jet recording apparatus. FIG. 6 is a diagram showing the configuration of the recording head 100 in more detail so that it can be easily understood. An ink supply box 401, an electric substrate 402, and a ceramic plate 403 are combined by screws 408. An electric board 402 and a heater board 404 on which a logic circuit, a heater, a temperature sensor, and the like are mounted are disposed on the ceramic plate 403, and the electrode terminal 504a of the electric board 402 and the terminal 504b of the heater board 404 are formed by wire bonding. Electrically connected. A nozzle wall is formed on the heater board 404, and a top plate 405 is bonded on the nozzle wall. The exposed portions of the connecting portion 406 and the electrode terminals 504a and 504b connected by wire bonding are sealed with a sealing agent such as silicon to prevent a short circuit and to prevent corrosion due to ink. Then, the recording head 100 is formed by screwing the ink supply box 401 in which the ink flow path and the liquid chamber 407 are formed.

  FIG. 7 is an external view of an electric substrate 402 that is an ink jet recording head substrate mounted inside the recording head 100. On the electric board, a ROM 501 for storing recording head specific information such as a serial number of the recording head 100 and a dot count, and a capacitor 502 for preventing a voltage effect are arranged between the VH power source and GND. A connector terminal 503 for connecting the recording head 100 and the recording apparatus main body and an electrode terminal 504a for wire bonding connection are arranged, and a signal pattern and a power source are spread over each layer of the multilayer substrate from the connector terminal to the electrode terminal 504a. The pattern is wired. This pattern is etched during the manufacturing process of the electric substrate, and after the copper foil pattern is formed, the surface is protected by a resist material.

  The terminal part has a gold-plated pattern disposed on the substrate surface. In particular, the electrode terminal 504a is close to the ink flow path and is covered with a sealant to avoid contact with the ink. However, when the sealing portion is long as in this embodiment, a gap is formed in the sealing portion due to external factors such as a use environment, and ink flows between the sealing agent and the electric substrate 402. There is a risk of creeking.

  In this embodiment, an ink leakage detection wiring pattern is arranged on the electric substrate 402 for the purpose of preventing such a short circuit between electrodes due to ink leakage and corrosion of the electrodes due to ink. FIGS. 8A to 8C are diagrams showing the wiring patterns 511, 512, and 513 of this embodiment, and are wired so as to detect ink leakage to the electrode terminal 504a. These wiring patterns are composed of a pair (two poles) of wiring, and are wired in the vicinity of a place where there is a problem when ink leakage occurs on the substrate surface. Since the wiring pattern for ink leakage detection is in a state where the wiring is exposed (no resist processing), the ink leakage detection function is activated when ink leaks and leaks across the two-pole pattern. Yes. For example, let us consider a case where ink flows from the portion J where the joint portion of the ink supply box 401 is present in the direction of the arrow in FIGS. In this embodiment, as shown in the figure, the ink leakage detection wiring pattern is provided so as to cover the entire upper portion of the electrode terminal 504a. By providing the ink leakage detection wiring pattern in this way, when ink leakage occurs, the ink leakage detection wiring pattern is reached and the two wiring patterns are short-circuited before the ink reaches the electrode terminal 504a. Ink leakage can be detected. As for the shape of the wiring pattern, linear wiring may be alternately arranged as shown in FIG. 8A, or a pair of comb-like wiring patterns as shown in FIGS. 8B and 8C. They may be arranged facing each other. In this case, it is desirable to arrange the wiring patterns facing each other so that the other comb tooth enters between one comb tooth.

  The present invention is characterized in that ink leakage is detected using a wiring pattern without forming electrode terminals with a conductive paste or the like separately from wiring on the substrate for detecting ink leakage (hereinafter referred to as wiring). A terminal formed without using a pattern is called a conductive paste terminal). When a new conductive paste terminal for ink leakage detection is provided on the electric substrate 402, it is necessary to add a new process for forming the conductive paste terminal in the manufacturing process of the electric substrate 402. However, by detecting the ink leakage by the wiring pattern, the number of layers of the electric substrate 402 being used is increased, and the wiring pattern for ink leakage detection can be made by not performing the resist process only on the wiring pattern portion. Therefore, it is not necessary to add a new process. In addition, since only two wirings are arranged on the electric substrate 402, the wiring board can be provided in a narrow portion. For example, the degree of freedom in providing the conductive paste terminal is higher than that in the detection. Of course, if there is room in the board space, the wiring pattern may be formed without increasing the number of layers of the board. Of course, in this case as well, only the wiring pattern portion is not subjected to resist treatment, and the wiring pattern is exposed.

  When ink leakage is detected using a conductive paste terminal, it is difficult to provide the conductive paste terminal on the entire surface of the electric substrate 402. However, the wiring pattern can be easily arranged on the entire surface of the electric substrate 402 by the method of detecting ink leakage by the wiring pattern as in the present embodiment. In addition, since the wiring pattern is used for detection, it is easy to continuously provide the ink leakage detection unit. Therefore, it is possible to reliably detect ink leakage depending on the shape of the wiring pattern. Therefore, it is an optimal detection method when it is desired to continuously provide a detection unit for a long and continuous part such as a long connection part as in this embodiment.

  The shape of the wiring pattern is not limited to the wiring patterns shown in FIGS. 8A to 8C, and the wiring pattern can be changed as appropriate according to the shape of the electric board and the arrangement of each component on the board. It is. Further, in FIGS. 8A to 8C, the ink leakage detection wiring pattern (hereinafter also simply referred to as a wiring pattern) is constituted by one series of circuits. However, the invention is not limited to this. You may comprise by a wiring pattern.

  FIG. 9 shows a flowchart of the ink leakage detection control of this embodiment. Hereafter, each process of a flowchart is demonstrated in order.

  First, when the power of the inkjet recording apparatus is turned on in step S11, initial ink leakage detection is started in step S12. Based on the detection result, it is determined in step S13 whether or not there is an ink leak. If there is an ink leak, the process proceeds to step S15, and if there is no ink leak, the process proceeds to step S14. If ink leakage is confirmed and the process proceeds to step S15, a warning is given to replace the recording head by using a buzzer, an operation panel or the like without turning on the VH power source that is the recording head power source. If the ink leakage is not confirmed in step S13 and the process proceeds to step S14, the VH power supply of the recording head power supply is turned on. After the VH power supply is turned on in step S14, the process proceeds to step S16, and it is determined whether or not there is ink leakage by constantly detecting ink leakage. If there is ink leakage in step S16, the process proceeds to step S18, and if there is no ink leakage, the process proceeds to step S17. When ink leakage is confirmed and the process proceeds to step S18, a print head replacement warning is issued and the VH power supply of the print head power supply is shut off. If the ink leakage is not confirmed in step S16 and the process proceeds to step S17, the recording is performed by the normal operation. Thereafter, the process proceeds to step S19, where it is determined whether the recording is finished. If the recording has not been completed in step S19, the process returns to step S16 again and the same process is repeated. In this way, ink leakage is always detected during recording. If ink leakage occurs during recording, a recording head replacement warning is immediately issued in step S18. If the recording is completed in step S19, the process ends.

  FIG. 10 is a block diagram illustrating an example of ink leakage detection control. Since the resistance value of the ink is high and alternating current is easier to detect than direct current, alternating current is used for the two-pole ink detection wiring pattern. Since there are four print heads for each color, for example, four colors K, C, M, and Y, the selector circuit 801 is used to load the ink detection wiring pattern of each print head with alternating current for a short time. To do.

  The current flowing between the pair of wiring patterns by the AC voltage for ink leakage detection is 0 A when there is no ink leakage. When there is ink leakage, the current value changes depending on the contact area between the ink and the wiring pattern and the quality of the ink. However, the current value is amplified to an appropriate current value by the amplification circuit 802 and the presence or absence of ink is detected by the comparison circuit 803. Can be recognized. The result of the comparison circuit is transmitted to the CPU, and processing at the time of ink leakage is executed.

  Ink leakage may be detected either by reading a resistance value between a pair of wiring patterns or by reading a current value between a pair of wiring patterns.

  As described above, the wiring pattern for ink leakage is provided on the electric substrate for supplying electric power to the energy element of the recording head at a location where a problem may occur when ink leakage occurs. And by detecting ink leakage when power is turned on and during recording, it is possible to increase the stacking of power supply boards without adding new processes when manufacturing electric boards, and to provide high reliability even for long connections. An ink jet recording head capable of detecting ink leakage was realized.

  In this embodiment, a full line type recording apparatus is used. However, the present invention is not limited to this, and the same effect can be obtained even when applied to a serial type recording apparatus.

  In this embodiment, a heater is used to prevent energy generation in ink ejection, and the heater board on which the heater is formed and the electric board are connected. However, the present invention is not limited to this, and other elements are used. May be. For example, a piezo element or the like may be used to prevent energy generation, and the board on which the piezo element is formed and the electric board may be connected.

1 is an external perspective view showing an ink jet recording apparatus to which the present invention is applicable. 1 is a schematic diagram of an ink jet recording apparatus using a line type recording head to which the present invention is applicable. It is a figure for demonstrating the recording method of the recording performed using an inkjet recording device. FIG. 6 is a diagram illustrating a transfer path of recording data. FIG. 2 is an exploded view of a recording head mounted on an ink jet recording apparatus. FIG. 3 is a diagram illustrating the configuration of the recording head in more detail so that the configuration of the recording head is easily understood. It is an external view of the electric board mounted in the inside of a recording head. (A) to (c) is a diagram showing an example of a wiring pattern of the present embodiment. 2 is a flowchart of ink leakage detection control according to the present embodiment. It is a block diagram showing an example of ink leakage detection control.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Recording head 200 Monitor 300 Recording apparatus 302 Control circuit 304 CPU
305 Reception memory 306 Recording memory 401 Ink supply box 402 Electric board 404 Heater board 405 Top plate 504 Terminal 801 Selector circuit 802 Amplifier circuit 803 Comparison circuit

Claims (5)

In an inkjet recording head having an electrical substrate inside and an ejection port capable of ejecting ink,
A pair of exposed wiring patterns is formed on the electrical substrate,
An ink jet recording head, wherein ink leakage can be detected by detecting a resistance value between the pair of patterns that changes due to ink adhering to the pair of wiring patterns.   The inkjet recording head according to claim 1, wherein the wiring pattern is disposed in the vicinity of an electrode provided on the electric substrate.   2. The wiring pattern according to claim 1, wherein the pair of wirings are comb-shaped wirings, and the other comb-shaped wiring is inserted between the one comb-shaped wirings. The ink jet recording head according to claim 2. Recording means for performing recording by the ink jet recording head according to any one of claims 1 to 3,
Means for applying a voltage to the pair of wiring patterns of the ink jet recording head;
When a voltage is applied to the pair of wiring patterns, ink leakage is detected by reading a current value flowing between the pair of wiring patterns based on a resistance value that changes due to ink adhering between the pair of wiring patterns. Detection means;
An ink jet recording apparatus comprising: In an inkjet recording head substrate used in an inkjet recording head having an ejection port capable of ejecting ink,
A pair of exposed wiring patterns is formed on the ink jet recording head substrate, and a resistance value between the pair of patterns that changes due to ink adhering to the pair of wiring patterns is detected. Thus, an ink jet recording head substrate capable of detecting ink leakage.

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