JP2018108673A - Recording element substrate, recording head, and recording apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve a problem that in a case where a substrate temperature is rapidly increased by driving a heating element from a condition in which an environmental temperature is low, the substrate temperature increases higher than expected, which may affect an ink emission characteristic.SOLUTION: A recording element substrate comprises: a plurality of recording elements; a plurality of first drive circuits respectively corresponding to the plurality of recording elements; a heating element that heats the recording element substrate; a second drive circuit that drives the heating element. The second drive circuit is formed from a source ground type MOS transistor and is provided with a resistive dividing part that generates a gate voltage supplied to the second drive circuit.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a recording element substrate, a recording head, and a recording apparatus.

  As one of information output devices for recording information such as desired characters and images on a recording medium such as paper or film, there is a liquid discharge recording device (hereinafter referred to as a recording device). The recording apparatus performs recording by landing droplets ejected from a liquid ejection head (recording head) on a recording medium. There are various types of liquid ejection by the liquid ejection head. A thermal ink jet method is well known as one of liquid discharge methods. The thermal ink jet method is a liquid discharge method in which the ink bubbling phenomenon induced by thermal energy generated by energizing a heater in contact with ink for about several microseconds is used for discharging ink droplets.

  In such a thermal ink jet recording head, when the usage environment is a low temperature environment away from room temperature, the ink temperature is lowered to near room temperature to reduce the viscosity of the ink and cause ejection failure due to the ink viscosity. Some perform temperature control to prevent it. Patent Document 1 discloses a technique for self-controlling a temperature adjusting resistance element by a thermistor as a method for controlling ink temperature due to environmental temperature.

Japanese Patent Laid-Open No. 2003-200589

  In a conventional thermal ink jet recording head, a resistance element for temperature control (hereinafter referred to as a sub-heater) is mounted on a recording element substrate on which a recording element that discharges ink is mounted, and the sub-heater generates heat so that the ink is printed together with the recording element substrate. The droplet is heated. At that time, based on the detection result of the temperature detection element, the current flowing through the sub-heater is controlled so as to keep the temperature of the recording element substrate in the range of 40 to 60 ° C. However, when the environmental temperature is extremely low, it is necessary to rapidly supply a current to the sub-heater to heat the ink together with the substrate in a short time during printing from the start of power supply. Therefore, in the conventional method of transmitting the temperature detection result to the recording apparatus main body and controlling the current of the sub-heater from the main body, a time lag is generated through the main body, and the substrate may be excessively heated. There is.

  Therefore, there is a technique in which the sub-heater is passively controlled in the head portion instead of controlling the sub-heater from the recording apparatus main body according to the temperature detection result as in Patent Document 1. However, in Patent Document 1, it is assumed that the temperature of the head outside the recording element substrate is controlled in the environmental temperature range of 30 to 40 ° C., and it is not assumed to be built in the substrate. Therefore, there is a problem that the accurate temperature of the recording element substrate cannot be detected, and the temperature control of the heating element on the substrate does not work correctly.

  In view of the above problems, the present invention has an object to stabilize the ink ejection characteristics by performing self-control of the sub-heater current in the recording element substrate without using the recording apparatus main body even when rapid temperature control is performed. And

  In order to solve the above problems, the present invention has the following configuration. That is, the recording element substrate includes a plurality of recording elements, a plurality of first drive circuits corresponding to the plurality of recording elements, a heating element for heating the recording element substrate, and driving the heating element. A second drive circuit, wherein the second drive circuit is formed of a source grounded MOS transistor, and is provided with a resistance voltage dividing unit that generates a gate voltage supplied to the second drive circuit.

  According to the present invention, it is possible to quickly suppress the temperature rise of the substrate without using the recording apparatus main body, and to secure stable ejection characteristics.

FIG. 6 is a plan view illustrating a configuration example of a recording element substrate of a comparative example. FIG. 3 is a plan view illustrating a configuration example of a recording element substrate according to the first embodiment. FIG. 6 is a plan view illustrating a configuration example of a recording element substrate according to a second embodiment. The figure which shows the equivalent circuit from a gate voltage generation part and a drive circuit to a sub heater. The figure which shows the equivalent circuit of the gate voltage generation part which concerns on 1st Embodiment. The figure which shows the equivalent circuit of the gate voltage generation part which concerns on 2nd Embodiment. The enlarged view of the board | substrate center part A which concerns on 1st Embodiment. The enlarged view of the board | substrate center part B which concerns on 2nd Embodiment. The graph which shows the relationship between the substrate temperature and sub heater current which concern on 1st Embodiment. The graph which shows the relationship between the substrate temperature and sub heater current which concern on 2nd Embodiment. The graph which shows the relationship between the substrate temperature and gate voltage which concern on 1st Embodiment. The graph which shows the relationship between the gate voltage which concerns on 1st Embodiment, and the MOS on-resistance of a drive circuit. The graph which shows the relationship between the substrate temperature which concerns on 1st Embodiment, and the MOS on-resistance of a drive circuit. The perspective view of a recording head. FIG. 3 is a perspective view of a recording element substrate to which a discharge port forming member is bonded.

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

  In this specification, “recording” (sometimes referred to as “printing”) is not limited to the case of forming significant information such as characters and graphics, but may be significant. Furthermore, it also represents a case where an image, a pattern, a pattern, or the like is widely formed on a recording medium or a medium is processed regardless of whether or not it is manifested so that a human 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.

  Further, “ink” (sometimes referred to as “liquid”) should be interpreted widely as in the definition of “recording (printing)”. Therefore, by being applied on the recording medium, it is used for formation of images, patterns, patterns, etc., processing of the recording medium, or ink processing (for example, solidification or insolubilization of colorant in the ink applied to the recording medium). It shall represent a liquid that can be made.

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

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

  An element substrate (head substrate) for a recording head to be used below does not indicate a simple substrate made of a silicon semiconductor but indicates a configuration in which each element, wiring, and the like are provided.

  Further, the term “on the substrate” means not only the element substrate but also the surface of the element substrate and the inside of the element substrate near the surface. The term “built-in” as used in the present invention is not a word indicating that individual elements are simply arranged separately on the surface of the substrate, but each element is manufactured in a semiconductor circuit. It shows that it is integrally formed and manufactured on an element plate by a process or the like.

  The recording head according to the present invention is used not only for a serial type recording apparatus described later, but also for a recording apparatus provided with a full line type recording head whose recording width corresponds to the width of the recording medium. Further, the recording head is used in a large format printer using a recording medium having a large size such as A0 or B0 among serial type recording apparatuses.

<First Embodiment>
[Circuit configuration]
A recording element substrate (hereinafter referred to as a recording element substrate) for an ink jet recording head prepared by applying the present invention will be described with reference to the drawings.

  FIG. 2 is a plan view illustrating a configuration example of the recording element substrate according to the first embodiment. The recording element substrate 100 includes a sub-heater 112 that is a heating element, a gate voltage generation unit 110, and a drive circuit 111.

  In FIG. 2, in order to heat the entire recording element substrate 100, three sub-heaters 112 are passed between the recording element selection circuit 104 around the ink supply port 106 and the recording element drive circuit 103. They are arranged in parallel. Further, the recording element substrate 100 includes a temperature detection element 102 for detecting its own temperature. A detection result as temperature information detected by the temperature detection element 102 is transmitted to the recording apparatus main body (not shown) via the terminal 101. This temperature information is used for drive control of the heater (recording element) 105, for example. In the present embodiment, a description will be given assuming that a plurality of terminals 101 are arranged on both sides of the recording element substrate 100. The shape of the gate voltage generation unit 110 is a strip shape as shown in FIG.

  FIG. 4 illustrates a sub-heater 112, a drive circuit 111, and a resistance voltage dividing unit (hereinafter also referred to as a resistance voltage dividing unit 110) that is a gate voltage generation unit 110 in the configuration according to the first embodiment illustrated in FIG. It is a figure which shows an equivalent circuit. For convenience, the drive circuit 103 for the recording element is also referred to as a first drive circuit, and the drive circuit 111 for the sub-heater 112 is also referred to as a second drive circuit.

  FIG. 5 is a diagram illustrating an example of a detailed circuit configuration of the resistance voltage dividing unit 110 according to the first embodiment. In the present embodiment, the resistance voltage divider 110 includes two elements 120a and 120b that are resistance components. The resistance voltage divider 110 is electrically connected to the gate terminal 111a of the drive circuit 111 between the element 120a to which the voltage is applied and the element 120b on the ground side.

  In the present embodiment, the drive circuit 111 is composed of a common source MOS transistor. The gate voltage generation unit 110 forms the element 120a on the terminal 101c side as a wiring made of AL-Si so as to have the equivalent circuit configuration shown in FIG. Note that the substance forming the element 120a is not limited to this, and the element 120a may be formed of other substances. Further, the GND-side element 120b is formed of a diode, and is disposed adjacent to the sub-heater 112 as shown in FIGS. FIG. 7 is an enlarged view of the sub-heater 112 in the central portion A of the substrate in FIG. 2 and the gate voltage generation unit 110 disposed in the vicinity thereof. As shown in FIG. 7, the resistance component on the GND side shown in FIG. 5 is arranged in the vicinity of the center of the heater 105 array. The central portion A of the substrate is a place where the temperature easily rises excessively during the recording operation. Not limited to this example, the GND-side element 120b may be disposed in a place where the temperature change is large.

  The sub-heater 112 generates heat when a current flows from the driving circuit 111 to the sub-heater 112 by the gate voltage generated by the gate voltage generation unit 110, and heats the recording element substrate 100 and the ink droplets.

  FIG. 14 is a perspective view showing a recording head 300 on which the recording element substrate according to the first embodiment is mounted. An electrical wiring member 302, an electrical wiring substrate 303, and a recording element substrate 301 (301a, 301b) are mounted on the housing 305. An ink tank 304 is attached to the housing 305. The ink stored in the ink tank 304 is introduced into the recording element substrate 301 through the recording head 300. FIG. 14 shows a configuration example of the recording head 300 in the serial type recording apparatus. However, as described above, the present invention is not limited to this configuration, and the present invention may be applied to a full-line recording head.

  FIG. 15 is a perspective view showing a recording element substrate 301 a mounted on the recording head 300. A heater 105 is disposed on the recording element substrate 100 in the recording element substrate 301a. An ink supply port 106 is formed in the recording element substrate 100. The heaters 105 are arranged along the ink supply port 106. Further, a flow path forming member 200 b and a discharge port forming member 200 a are provided on the recording element substrate 100, and the discharge port forming member 200 a forms a discharge port 201 corresponding to the heater 105. Further, a voltage and a signal are supplied from the outside to the recording element substrate 100 through the terminal 101.

[Description of Effects According to the Present Embodiment]
In order to confirm the effect of the first embodiment, a circuit configuration shown in FIG. 1 is used as a comparative example. Note that the configuration other than the circuit configuration is the same as that of the first embodiment described above, and a description thereof is omitted.

  FIG. 1 is a plan view showing a recording element substrate of a comparative example on which a resistance element for temperature adjustment (hereinafter referred to as a sub-heater) 112 for heating the recording element substrate 100 is mounted. In the comparative example, as compared with the configuration of FIG. 2 according to the first embodiment, the drive circuit 111 for driving the sub-heater 112 and the gate voltage generation unit 110 are arranged adjacent to each other in the vicinity of the terminals. . Here, a set of three drive circuits and the gate voltage generation unit 110 is arranged corresponding to 112 in three columns.

  A case where the sub-heater 112 is heated using the recording head having the configuration of the first embodiment and the recording head having the configuration of Comparative Example 1 will be described. Here, a case will be described in which heating is performed while a constant current is supplied to the sub-heater 112 so that the temperature indicated by the temperature detection element 102 on the recording element substrate 100 is 50 ° C. from a state where the environmental temperature is 5 ° C. At that time, all the heaters are driven, and the ejection characteristics of the ink ejected from each heater, the substrate temperature output from the temperature detection element 102 on the recording element substrate 100, and the sub-heater current are measured simultaneously.

  As a result of the measurement, in the configuration of Comparative Example 1, when the substrate temperature reached around 50 ° C., ink pooled around the ejection port near the center of the substrate, and ink droplets were normal from the surrounding ejection port. It was not discharged. When the temperature of the surface of the substrate when this ink pool is observed is not the value of the temperature detection element on the substrate, but separately observed using thermography, the temperature around the center of the substrate rises to around 70 ° C. It was warm.

  This is because when the environmental temperature is raised from a low temperature (5 ° C.), the substrate temperature is rapidly increased to the desired temperature in the same time as when the environmental temperature is raised from the normal temperature (25 ° C.). The heating was done. As a result, it was found that the substrate temperature around the sub-heater in the central portion A of the substrate was higher than the temperature indicated by the temperature detection element 102. For this reason, the ink temperature in the vicinity of the sub-heater together with the recording element substrate is excessively raised, so that the characteristics of the ink change and undischarge occurs.

  On the other hand, in the configuration of the first embodiment, when the temperature indicated by the temperature detection element is in the vicinity of 45 ° C., which is lower than 50 ° C., the substrate temperature converges and no ink droplet discharge is observed. When the temperature of the substrate surface at this time was similarly confirmed using thermography, the temperature at the center of the substrate showed a value of less than 60 ° C. Further, when the current flowing through the sub-heater 112 at this time was confirmed, it was found that the current of the sub-heater 112 decreased from around 60 ° C. as shown in FIG.

  The above reason will be described in more detail with reference to FIGS. 9, 11, and 12. FIG. 9 shows the relationship between the current and temperature of the sub-heater 112 of the printing element substrate 100 shown in FIG. 2 according to the present embodiment. The vertical axis represents the sub-heater temperature [mA], and the horizontal axis represents the temperature [° C.]. As shown. FIG. 11 shows the relationship between the gate voltage generated by the resistance voltage divider 110 according to this embodiment and the temperature. The vertical axis represents the gate voltage [V], and the horizontal axis represents the temperature [° C.]. As shown. FIG. 12 shows the relationship between the resistance value [Ω] of the drive circuit 111 which is a common source MOS transistor according to the present embodiment and the gate voltage [V] generated by the resistance voltage dividing unit 110.

  In the present embodiment, since the element on the GND side of the resistance voltage dividing unit 110 is formed of a diode (element 120b) having a negative temperature characteristic, the element on the GND side of the resistance voltage dividing unit 110 according to a temperature rise. The resistance value of 120b decreases. As a result, the gate voltage generated by the resistance voltage divider 110 also decreases as shown in FIG. Further, the drive circuit 111 formed of the common source MOS transistor shows the characteristics as shown in FIG. 12 according to the gate voltage, and when the gate voltage drops to around 7 V, the MOS on resistance suddenly increases. To rise. As a result, as shown in FIG. 9, when the substrate temperature indicated by the thermography reaches around 60 ° C., the current to the sub-heater 112 decreases. Therefore, the excessive temperature rise of the substrate and the ink around the sub heater 112 can be suppressed without going through the recording apparatus main body, and as a result, ink non-discharge can be prevented.

  Further, as shown in FIG. 7, the elements 120a and 120b of the resistance voltage dividing unit 110 are arranged in the vicinity of the sub-heater 112, so that the physical distance to the heat generation source is reduced as compared with the temperature detection element in the vicinity of the terminal. The improvement in responsiveness to temperature changes is also cited as a factor for preventing undischarge.

  Furthermore, FIG. 13 shows the relationship between the resistance value [Ω] and the temperature [° C.] of the drive circuit 111 formed of a common source MOS transistor. As shown in FIG. 13, the drive circuit 111 itself formed of a source-grounded MOS transistor also has a characteristic that the MOS on-resistance increases as the temperature increases. Therefore, with the configuration of this embodiment, it is assumed that the temperature of the drive circuit 111 itself is also suppressed.

<Second Embodiment>
A second embodiment of the present invention will be described with reference to the drawings. FIG. 3 is a diagram illustrating an example of a planar configuration of a recording element substrate according to the second embodiment of the present invention. Note that an equivalent circuit of the sub-heater 112, the drive circuit 111, and the resistance voltage divider 110, which is a gate voltage generator, according to the present embodiment is the same as that of FIG. 4 described in the first embodiment. FIG. 6 shows details of an equivalent circuit diagram of the resistance voltage divider 110 of the second embodiment.

  In this embodiment, as a point different from the first embodiment, the gate voltage generators 110a and 110b are connected and arranged in a two-stage configuration as shown in FIG. Further, the gate voltage generation units 110a and 110b are arranged with the sub heater 112 interposed therebetween as shown in FIG. Since other configurations are the same as those of the first embodiment, description thereof is omitted.

[Description of Effects According to the Present Embodiment]
Using the recording head having the configuration of the second embodiment, confirmation of ejection characteristics and monitoring of the substrate temperature and the sub-heater current were performed. FIG. 10 shows the relationship between the current and temperature of the sub-heater 112 of the recording element substrate 100 shown in FIG. 6 according to the present embodiment, where the vertical axis is the sub-heater temperature [mA] and the horizontal axis is the temperature [° C.]. As shown. As a result, in the configuration of the second embodiment, as shown in FIG. 10, when the temperature indicated by the temperature detection element reaches around 45 ° C., the current of the sub-heater 112 rapidly decreases together with the gate voltage. It was.

  This is because the gate voltage generated by the first gate voltage generator 110a in the two-stage gate voltage generator 110 is affected by the temperature characteristics of the gate voltage generator 110b on the drive circuit 111 side. Thus, the characteristic that the gate voltage is further lowered as the temperature rises is shown. As a result, since the gate voltage generator 110 has a two-stage configuration, the current of the sub-heater 112 in a region lower than 50 ° C., which is the temperature at which the current of the sub-heater 112 starts to decrease in the first embodiment. It turns out that it is suppressing.

  As described above, by forming the gate voltage generation unit in a two-stage configuration, even when the optimum ink ejection temperature is lower than that in the first embodiment, the substrate around the sub-heater 112 and the ink are prevented from excessively rising in temperature. However, the ink ejection characteristics can be ensured.

  In the present embodiment, the gate voltage generation unit is arranged in a two-stage configuration, but a three-stage or more configuration may be used.

<Other embodiments>
In the second embodiment, the element 120a and the element 120c on the terminal side of the resistance voltage divider 110 are elements that exhibit positive temperature characteristics, and the element 120b and the element 120d on the GND side are elements that exhibit negative temperature characteristics, respectively. It is configured. However, if the temperature characteristic of the GND side element shows a characteristic that the resistance value is lower with respect to the temperature than the terminal side element, a positive or negative temperature characteristic element on both the terminal side and the GND side of the resistance voltage divider is Even if it is used, the same effect can be obtained. In other words, the GND-side element only needs to have a configuration in which an increase in resistance value due to a temperature rise is small compared to a terminal-side element.

  In addition, about two types of temperature characteristic elements each arrange | positioned at said terminal side and GND side, in each embodiment, the structure which has arrange | positioned only one element was shown. However, the present invention is not limited to this configuration. For example, the same effect can be obtained by a configuration in which a plurality of each is connected.

  In each embodiment, the ink supply port 106 has a configuration of two holes (two rows). However, the present invention is not limited to this configuration. For example, if it is arranged in the vicinity of the sub-heater or so as to overlap with the sub-heater when viewed from the upper surface of the recording element substrate, the same effect can be obtained even with a configuration of three or more holes. can get.

  In addition to the above, a configuration in which the planar shape of the recording element substrate is other than a rectangle such as a parallelogram, and a plurality of ink supply ports opened perpendicular to the substrate plane are provided per heater array. The same effect can be obtained even with this substrate.

DESCRIPTION OF SYMBOLS 100: Board | substrate, 101: External connection terminal, 105: Recording element, 106: Ink supply port, 110: Gate voltage generation part, 111: Sub heater drive circuit, 112: Sub heater, 120a: Element (terminal side resistance component), 120b: Element (GND side resistance component)

Claims (15)

A recording element substrate,
A plurality of recording elements;
A plurality of first drive circuits corresponding to each of the plurality of recording elements;
A heating element for heating the recording element substrate;
A second drive circuit for driving the heating element;
With
The second drive circuit includes:
Formed by a common source MOS transistor,
A recording element substrate, comprising: a resistance voltage dividing unit that generates a gate voltage supplied to the second drive circuit. The resistance voltage dividing unit is
At least a first resistance component on the side to which a voltage is applied and a second resistance component on the ground side,
The recording element substrate according to claim 1, wherein the recording element substrate is electrically connected to a gate terminal of the second drive circuit between the first resistance component and the second resistance component.   The recording element substrate according to claim 2, wherein each of the first resistance component and the second resistance component includes an element having at least one resistance component.   4. The recording element substrate according to claim 2, wherein the second resistance component has a smaller increase in resistance value due to a temperature rise than the first resistance component. 5. The first resistance component is formed of a positive temperature characteristic element,
The recording element substrate according to claim 2, wherein the second resistance component is formed of a negative temperature characteristic element.   The recording element substrate according to claim 2, wherein the first and second resistance components are formed of negative temperature characteristic elements.   The recording element substrate according to claim 2, wherein the first and second resistance components are formed of positive temperature characteristic elements.   The recording element substrate according to claim 5 or 7, wherein the positive temperature characteristic element is formed of AL-Si.   The recording element substrate according to claim 5, wherein the negative temperature characteristic element is a diode.   10. The device according to claim 2, wherein at least the second resistance component among the resistance components constituting the resistance voltage dividing unit is disposed adjacent to the heating element. 11. Recording element substrate. The resistance voltage dividing unit includes a first resistance voltage dividing unit on a side to which a voltage is applied and a second resistance voltage dividing unit connected to the driving circuit,
Each of the first resistance voltage dividing unit and the second resistance voltage dividing unit includes at least a first resistance component on a side to which a voltage is applied and a second resistance component on the ground side,
The gate voltage formed by the first resistance voltage dividing unit is electrically connected so as to be applied to a first resistance component in the second resistance voltage dividing unit. The recording element substrate according to 1.   The recording element substrate according to claim 1, wherein at least two of the resistance voltage dividing portions are formed. A recording element substrate,
A plurality of recording elements;
A plurality of first drive circuits corresponding to each of the plurality of recording elements;
A heating element for heating the recording element substrate;
A second drive circuit for driving the heating element;
A gate voltage generator for generating a gate voltage supplied to the second drive circuit;
With
The second drive circuit includes:
Formed including a common source MOS transistor,
A resistance voltage dividing unit for generating a gate voltage supplied to the source grounded MOS transistor is provided;
The recording element substrate, wherein the gate voltage decreases with an increase in temperature of the recording element substrate.   A recording head comprising one or a plurality of recording element substrates according to claim 1.   A recording apparatus comprising one or more recording heads according to claim 14.

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