JP2008105224A - Inkjet recording substrate, recording head and recording apparatus provided with the substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power-efficient recording substrate and a recording head and a recording apparatus provided with the substrate, in which a high-density and a large number of heaters are arranged in the substrate to enable high-quality and high-speed printing, which is higher than conventional ones. Provide records.
A power supply wiring is formed with a plurality of wiring layers with an insulating layer on a transistor, a ground wiring is formed with a plurality of wiring layers with an insulating layer on a drive circuit, and a long wiring has a thick wiring layer. Use short individual wiring with thin wiring layers.
[Selection] Figure 1

Description

  The present invention relates to a recording head substrate, a recording head including the recording head substrate, and a recording apparatus having the recording head, and in particular, a recording head substrate that performs recording on a recording medium by discharging ink according to an ink jet method. The present invention relates to a recording head including the recording head substrate and a recording apparatus having the recording head.

  A recording head mounted on a recording apparatus according to a conventional ink jet system has a circuit configuration as shown in FIG. Such a thermal conversion element (heater) of the recording head and its drive circuit are formed on the same substrate by using a semiconductor process technique as disclosed in, for example, Japanese Patent Laid-Open No. 5-185594.

  In FIG. 10, 1101 is a heat conversion element (heater) for generating thermal energy, 1102 is a transistor section for supplying a desired current to the heater 1101, and 1104 is a nozzle for the recording head by supplying current to each heater 1101. A shift register for temporarily storing image data indicating whether or not to eject recording liquid (ink) from the transfer clock (CLK) input terminal 1107 provided in the shift register 1104, 1106 for turning the heater 1101 ON / OFF Image data input terminal for serially inputting image data (DATA) 1103 is a latch circuit for recording and holding image data for each heater for each heater, 1108 is a latch timing signal (LT) input to the latch circuit 1103 The latch signal input terminal 1109 supplies current to the heater 1101. A switch for determining timing, 1105 is a power supply wiring (power supply line) for applying a predetermined voltage to the heater and supplying a current, and 1110 is a ground wiring (GND line) for grounding the heater 1101 via the transistor 1102. . The number of image data bits stored in the shift register 1104, the number of transistors 1102, and the number of heaters 1101 are the same.

  FIG. 11 is a timing chart of various signals for driving the drive circuit of the recording head shown in FIG. The operation of the drive circuit of the recording head shown in FIG. 10 will be described using this. A transfer clock (CLK) corresponding to the number of bits of image data stored in the shift register 1104 is input to the transfer clock input terminal 1107. Assuming that data transfer to the shift register 1104 is performed in synchronization with the rising timing of the transfer clock (CLK), image data (DATA) for turning on / off each heater 1101 is input from the image data input terminal 1106. Is done. Here, since the number of bits of the image data stored in the shift register 1104 is the same as the number of heaters and transistors, a transfer clock (CLK) pulse is input by the number of heaters 1101 to input image data (DATA). Is transferred to the shift register 1104, a latch signal (LT) is applied to the latch signal input terminal 1108, and image data corresponding to each heater is held in the latch circuit 1103. After that, if the switch 1109 is turned ON for an appropriate time, the current flows through the power supply line 1105 to the transistor 1102 and the heater 1101 according to the length of the switch 1109 being in the ON state. Flow into line 1110. At this time, the heater 1101 generates heat necessary for ejecting ink, and ink corresponding to the image data is ejected from the nozzles of the recording head.

  FIG. 5 is a diagram showing the layout of the recording head substrate of the first conventional example disclosed in Japanese Patent Laid-Open No. 8-108536, and FIG. 6 is a schematic diagram of the substrate along the line aa ′ shown in FIG. It is sectional drawing. In FIG. 5, reference numeral 1101 denotes a heater, 1102 denotes a transistor, and 1203 denotes a drive circuit. Reference numeral 1105 denotes a power supply line for applying a predetermined voltage to the heater 1101, and 1110 denotes a GND line for grounding the heater 1101 through the transistor 1102.

  Here, the power supply line 1105 is a wiring formed of the second wiring layer, and is formed above the transistor 1102 with an insulating layer interposed therebetween. The GND line 1110 is a wiring formed of the second wiring layer, and is formed above the driving circuit 1203 with an insulating layer interposed therebetween. In the conventional example 1, the power supply line 1105 and the GND line 1110 employ a method in which wiring connected to all the heaters in the nozzle row is provided by a single wiring (common wiring). The power supply line 1105 and the GND line 1110 are On the substrate, power supply electrode pads 1111 and GND electrode pads 1112 are provided as external electrical connection terminals, respectively.

  FIG. 7 is a diagram showing the layout of the recording head substrate of Conventional Example 2 disclosed in Japanese Patent Laid-Open No. 10-44416. FIG. 9 is a diagram of the substrate along the line aa ′ shown in FIG. It is a schematic cross section. In FIG. 7, reference numeral 1101 denotes a heater, 1102 denotes a transistor, and 1203 denotes a drive circuit. Reference numeral 1105 denotes a power supply line for applying a predetermined voltage to the heater 1101, and 1110 denotes a GND line for grounding the heater 1101 through the transistor 1102.

  Similar to Conventional Example 1, the power supply line 1105 is a wiring formed of the second wiring layer, and is formed above the transistor 1102 with an insulating layer interposed therebetween. The GND line 1110 is a wiring formed of the second wiring layer, and is formed above the driving circuit 1203 with an insulating layer interposed therebetween.

  In this conventional example 2, the power supply line 1105 and the GND line 1110 employ a method of providing a plurality of wirings (in this case, four wirings) (individual wirings) connected to all heaters in the nozzle row. 1105 and the GND line 1110 each have a power supply electrode pad 1111 and a GND electrode pad 1112 on the substrate as external electrical connection terminals.

  In the conventional example 1 of FIG. 5, since the current flowing through all the heaters is provided by a single wiring (common wiring), the wiring resistance value is constant because the wiring is common, but the number of simultaneously driven heaters at the time of simultaneous driving discharge ( The total current amount (assuming to be four) flows through the same wiring, and there is a feature that a difference in voltage drop occurs due to the difference in current amount between discharging all nozzles and discharging one nozzle.

In the conventional example 2 of FIG. 7, the number of wirings (four in this case) is provided by the number of simultaneously driven heaters at the time of simultaneous driving and discharging of all heaters, and the heater group (time division block group) that does not simultaneously drive and discharge is the same wiring ( Although the number of wires increases and the resistance of one wire increases to some extent, the current flowing through the individual wires is the same as the current during single discharge, and all nozzles are discharged. And a difference in voltage drop due to a difference in current amount during one discharge does not occur.
JP-A-5-185594 JP-A-8-108536 Japanese Patent Laid-Open No. 10-44416 Japanese Patent Laid-Open No. 10-181022

  In recent inkjet printers, in order to obtain a high-quality image, the droplet size of the ejected ink has been reduced. On the other hand, an increase in printing speed is also required, but the same amount of ink is required to simply form the same image. Obviously, if only the droplets of the ejected ink are reduced, the print speed is halved if the number of ejected ink droplets is halved.

  In order to prevent a decrease in printing speed, it is necessary to double the number of heaters in order to drive the same amount of ink. If the number of heaters is doubled while keeping the heater pitch unchanged, the size of the substrate on which the heaters are arranged will be doubled or larger, and the recording head that moves at high speed in the printer will be enlarged, resulting in manufacturing. In addition to incurring the above problems, the size of the printer is increased, and vibration and noise are increased. Therefore, it is necessary to increase the heater pitch.

  On the other hand, in order to obtain a stable ejected ink droplet, a stable voltage must be applied to the heater. When all the heaters are driven simultaneously, a large current flows at a time, and the voltage drops greatly due to the wiring resistance. For this reason, the number of heaters that are driven simultaneously is limited, and stable ink droplets are obtained by driving sequentially by dividing time. However, the driving time per one time is close to the limit in the current driving method, and it is necessary to increase the number of heaters that are driven simultaneously in order to suppress the speed reduction.

  The layout on the recording head substrate shown in the above conventional example is such that the power supply line 1105 applied to the heater 1101 and the GND line 1110 grounding the heater via the transistor 1102 are laid out by wiring of only one layer of the second wiring layer. Therefore, when a higher density and larger number of heaters that enable higher image quality and higher speed printing than before are arranged in the board, the wiring resistance of the power supply line and the GND line increases proportionally as the heater row is extended. Since the voltage drop from the power supply voltage becomes large, there is a disadvantage that power efficiency is lowered. In addition, the high-density heater arrangement leads to an increase in the number of simultaneously driven heaters, and the voltage drop in the power supply line and the GND line increases due to an increase in the current flowing through the wiring, which also causes a disadvantage that power efficiency is lowered. . If the voltage drop becomes large, it becomes difficult to drive the heater properly, and if it is remarkable, the print quality and durability may be lowered. The reduction in power efficiency is an energy loss other than the energy for ejecting ink, and is generally dissipated as unnecessary heat. Since this heat generation induces an increase in the temperature of the substrate, if it is noticeable, it may affect the ink ejection and may cause deterioration in printing quality and hindering speeding up.

  The problem of the conventional example is a common problem in the conventional example 1 using the common wiring and in the conventional example 2 using the individual wiring. In particular, the conventional example 2 has the following problems.

  A feature of the individual wiring is that it has the number of wirings that are simultaneously discharged to all the heaters of the nozzle row, and the wiring resistance values of all the wirings are made substantially uniform. Therefore, when higher density and more heaters that enable higher image quality and higher speed printing than before are arranged in the board, the above problems such as the extension of the heater array and the increase in the number of simultaneously driven heaters are the common wiring. Although only the width and the wiring film thickness are concerned, the number of wirings, the wiring width, the wiring film thickness, and the wiring interval are increased in the individual wiring, and the elements are more complicated.

  First, with regard to the number of wires, increasing the number of heaters leads to an increase in the number of heaters that are driven simultaneously, so the number of wires needs to be increased accordingly. Moreover, each individual wiring must have a wiring width sufficient to satisfy the current required for ejection. In addition, each individual wiring needs to be completely separated on the circuit, and a certain wiring interval needs to be taken in order to avoid a wiring short-circuit problem.

  Also, in order to make the wiring resistance values of all the wirings, which are the characteristics of the individual wirings, substantially uniform, the individual wirings are only one layer of the second wiring layer, and the wiring thicknesses of all the wirings are the same. Each individual wiring with a different distance from the pad to the heater must be adjusted only by the wiring width, and it is necessary to achieve a uniform wiring resistance value. The short individual wiring has a narrow wiring width, and the long individual wiring has a wide wiring width. This is realized.

  The problem here is the individual wiring region width (the entire region width including the wiring width and the wiring interval). When the individual wiring is configured, the transistor area and the power wiring area are overlapped, and the driving circuit area and the ground wiring area are overlapped, which are the characteristics of miniaturization described in Japanese Patent Laid-Open No. 8-108536. In order to realize this, there is a limit to the width of the individual wiring area. As a result, the number of heaters that can be increased is limited, making it difficult to realize high-quality and high-speed printing that is higher than conventional ones.

  In view of the above-described problems in the conventional example, the present invention has an object to provide a miniaturized recording head substrate that enables high-quality and high-speed printing, and a recording head and a recording apparatus including the substrate. Yes.

  In order to achieve the above object, the present invention inputs a thermal conversion element (heater) array for applying energy for ejecting a recording liquid (ink), a transistor array for operating the thermal conversion element (heater), and the transistor. A drive circuit array driven by signals is sequentially arranged, and the substrate on which the transistor and the drive circuit are wired using the first wiring layer which is the lowest wiring layer has the following characteristics.

  1. A power supply wiring (power supply line) for supplying power to the heat conversion element (heater) includes a part or all of the transistor row region, except for the lowermost wiring layer with an insulating layer sandwiched between the transistors. In the region where the ground wiring (GND line) of the thermal conversion element (heater) through the transistor includes a part or all of the drive circuit row region, It is formed of a plurality of wiring layers other than the lowermost wiring layer with an insulating layer interposed therebetween, and the thermal conversion element (heater) row, the power supply wiring (power supply line) group, and the ground wiring (GND line) group include They are arranged sequentially.

  2. The plurality of wiring layers other than the lowermost lowermost layer have different film thicknesses.

  3. The power supply wiring (power supply line) and the ground wiring (GND line) have a plurality of divided wirings (individual wirings) having substantially the same wiring resistance in the same and different wiring layers.

  4). The power supply wiring (power supply line) and the ground wiring (GND line) are divided wiring (individual wiring) in which a long wiring uses a thick wiring layer, a short wiring uses a thin wiring layer, and wiring resistance is formed to be almost equal. have.

  In the substrate, the long wiring of the power supply wiring (power supply line) and the ground wiring (GND line) is a long wiring connected to a heat conversion element (heater) near the center of the substrate, and the short wiring is near the end of the substrate. The short wiring connected to the heat conversion element (heater) may be used.

  In the substrate, a power supply wiring (power supply line) for supplying power to the heat conversion element (heater) includes a part or all of the transistor array region, and an insulating layer is sandwiched between the transistors. In a region where the ground wiring (GND line) of the heat conversion element (heater) formed by the second and third wiring layers and including the transistor includes a part or all of the driving circuit row region, A second wiring layer and a third wiring layer may be formed above the drive circuit with an insulating layer interposed therebetween.

  The substrate may include a supply port for supplying a recording liquid (ink) and a discharge port forming member for forming a discharge port for discharging the recording liquid (ink).

  The wiring layer may be aluminum, copper, gold, or an alloy containing aluminum, copper, and gold.

  As described above, the present invention provides a heat conversion element (heater) array for applying energy for ejecting a recording liquid (ink), a transistor array for operating the heat conversion element (heater), and the transistor driven by an input signal. The drive circuit row to be arranged is sequentially arranged, and power is supplied to the heat conversion element (heater) in the substrate on which the transistor and the drive circuit are wired using the first wiring layer which is the lowest wiring layer. A power supply wiring (power supply line) is formed in a plurality of wiring layers other than the lowermost wiring layer with an insulating layer sandwiched between the upper part of the transistors in a region including part or all of the transistor array region, In a region in which the ground wiring (GND line) of the heat conversion element (heater) interposed includes a part or all of the drive circuit row region, the upper part of the drive circuit The insulating layer is formed with a plurality of wiring layers other than the lowermost wiring layer, and the thermal conversion element (heater) row, the power supply wiring (power supply line) group, and the ground wiring (GND line) group are sequentially aligned. The plurality of wiring layers other than the lowermost wiring layer have different film thicknesses, and the power supply wiring (power supply line) and the ground wiring (GND line) have a wiring resistance in the same and different wiring layers. The power supply wiring (power supply line) and the ground wiring (GND line) use a thick wiring layer for a long wiring and a thin wiring layer for a short wiring. And having the divided wirings (individual wirings) formed so that the wiring resistances are substantially equal to each other, thereby enabling a miniaturized recording head substrate that enables high-quality and high-speed printing higher than the conventional one, a recording head including the substrate, and a recording head It is possible to provide a device.

  The present invention relates to the inside of a recording head substrate used in a recording head and a recording apparatus, and is a development of generally referred edge shooter type and side shooter type ink jet recording techniques. Each element constituting the present invention will be described step by step.

(1) Recording Head A recording head using the recording head substrate shown in the embodiment of the present invention will be described.

  FIG. 12 is a perspective view showing an example of an edge shooter type ink jet recording head using the recording head substrate of Example 1 shown in FIG. A photosensitive resin that forms a liquid flow path is laminated on the substrate 181, and the flow path wall 184 is molded by a photolithography technique. Subsequently, a cover plate 182 in which the ink supply port 183 is formed is stacked. The substrate 181, the flow path wall 184, and the lid plate 182 are simultaneously cut to form discharge ports, discharge nozzles, and liquid chambers at the same time.

  FIG. 13 is a perspective view showing an example of a side shooter type ink jet recording head using the recording head substrate of Example 2 shown in FIG. A photosensitive resin that forms a liquid flow path is laminated on the substrate 191, and the flow path wall 195 is formed by photolithography. Subsequently, an orifice plate 192 in which the discharge port 194 is formed is produced by electroforming, and is adhered onto the flow path wall 195. Thereby, a discharge port, a discharge nozzle, and a liquid chamber are formed simultaneously. Finally, the ink supply tube 193 is bonded to the ink supply port of the substrate 191.

  The ink jet recording head configured as described above can be combined with a container for containing ink to form a recording head cartridge. In particular, color recording can be performed by configuring a recording head cartridge by combining a container for storing a plurality of colors and a substrate for each color.

(2) Recording Device A recording device capable of mounting the above-described cartridge type recording head will be described. FIG. 14 is an explanatory diagram showing an example of a recording apparatus in which the recording head of the present invention can be mounted.

  In the recording apparatus shown in FIG. 14, the recording head cartridge H1000 is mounted on the carriage 102 so as to be replaceable. The carriage 102 is connected to each ejection unit via an external signal input terminal on the recording head cartridge H1000. An electrical connection for transmitting drive signals and the like is provided.

  The carriage 102 is guided and supported so as to reciprocate along a guide shaft 103 installed in the apparatus main body extending in the main scanning direction. The carriage 102 is driven by a main scanning motor 104 via drive mechanisms such as a motor pulley 105, a driven pulley 106, and a timing belt 107, and its position and movement are controlled. A home position sensor 130 is provided on the carriage 102. This makes it possible to know the position of the shielding plate 136 when the home position sensor 130 on the carriage 102 passes.

  A recording medium 108 such as a printing paper or a plastic thin plate is separated and fed one by one from an auto sheet feeder (ASF) 132 by rotating a pickup roller 131 from a paper feed motor 135 via a gear. Further, by the rotation of the conveyance roller 109, the conveyance roller 109 is conveyed (sub-scanned) through a position (print unit) facing the discharge port surface of the recording head cartridge H1000. The conveyance roller 109 is performed via a gear by the rotation of the LF motor 134. At this time, the determination of whether or not the paper has been fed and the determination of the cueing position at the time of paper feeding are performed when the recording medium 108 passes through the paper end sensor 133. Further, the paper end sensor 133 is also used to finally determine the current recording position from the actual rear end where the rear end is located.

  The recording medium 108 is supported by a platen (not shown) on the back surface so that a flat print surface is formed in the printing unit. In this case, the recording head cartridge H1000 mounted on the carriage 102 is held so that the discharge port surfaces thereof protrude downward from the carriage 102 and are parallel to the recording medium 108 between the two pairs of conveying rollers. Yes.

  The recording head cartridge H1000 is mounted on the carriage 102 so that the direction of the ejection ports in each ejection unit intersects the scanning direction of the carriage 102 described above, and ejects liquid from these ejection port arrays. Make a record.

(3) Printhead Substrate A plurality of embodiments will be described with respect to the printhead substrate that is the center of the configuration of the present invention.

  2 and 1 are diagrams showing the layout of a recording head substrate in Embodiment 1 of the present invention. Multi-layer wiring technology is used for this substrate, and wiring (aluminum, copper, gold or wiring made of an alloy containing aluminum, copper, gold) that connects each component is sandwiched between insulating layers, and a multilayer structure is formed on the substrate. Is made. In each wiring layer, upper and lower wirings are connected to each other by a through hole (an opening in the insulating layer) at an arbitrary position on the substrate.

  FIG. 4 is a schematic cross-sectional view of the substrate taken along line a-a ′ shown in FIG. 2. According to this example, the heater 1101 is formed in the third wiring layer, but this is an example for explanation, and the present invention is not limited thereto. 7 and 9 are a layout view and a schematic cross-sectional view of the recording head substrate of the second conventional example. 7 uses the same reference numerals as FIG. 2 and FIG. 9 use the same reference numerals as those in FIG. 4, and the figures correspond to each other.

  Although FIGS. 1 to 9 are not shown in the drawing, the print head substrate temporarily receives an image signal having the number of bits corresponding to the number of heaters 1101 as shown in FIG. And a latch circuit 1103 for latching an image signal stored in the shift register 1104. Further, an image data input terminal 1106 for inputting the image signal, a transfer clock input terminal 1107 for transferring the image signal, and a latch signal input terminal 1108 for inputting a latch signal are provided. Together with a switch (gate) 1109 for switching transistors, these circuits are collectively treated as a drive circuit (drive logic circuit group) 1203 in FIGS.

  1-2 and FIG. 4 are demonstrated. A heater (heater array) 1101 (1201), a transistor (transistor array) 1102, and a drive circuit (drive circuit array) 1203 are sequentially arranged on the printhead substrate 1000. Characteristic features 1105 and 1205 of the present invention are power supply lines for applying a predetermined voltage to the heater 1101, and 1110 and 1210 are GND lines for grounding the heater 1101 via the transistor 1102. The power supply line 1105 is a wiring formed in the second wiring layer, and is formed above the transistor 1102 via an insulating layer. The power supply line 1205 is a wiring formed in the third wiring layer, It is formed above the line 1105 via an insulating layer. Similarly, the GND line 1110 is a wiring formed in the second wiring layer, and is formed above the drive circuit 1203 via an insulating layer. The GND line 1210 is a wiring formed in the third wiring layer. Yes, and formed above the GND line 1110 via an insulating layer. The power supply line and the GND line each have a power supply electrode pad 1111 and a GND electrode pad 1112 on the substrate as external electrical connection terminals.

  The third wiring layer is thicker than the second wiring layer, the second wiring layer is thinner than the third wiring layer, and the power line 1105 using the third wiring layer is connected to the heater array from the power electrode pad 1111. Used for longer individual wiring extending to the central portion, and the power line 1205 using the second wiring layer is used for shorter individual wiring extending from the power supply electrode pad 1111 to the end portion of the heater array, and is combined with the wiring width for each individual wiring. The GND line 1110 is composed of a power supply line in which the wiring resistance of the wiring is adjusted to be substantially equal, and the GND line 1110 using the third wiring layer is used for a longer individual wiring extending from the GND electrode pad 1112 to the central portion of the heater array. The GND line 1210 is used for shorter individual wiring extending from the GND electrode pad 1112 to the end of the heater array, and the wiring resistance of each individual wiring is combined with the wiring width. It is composed of a GND line which is substantially equal adjust.

  On the other hand, the signal line connected to the transistor 1102 (specifically, the source / drain / gate electrodes of the transistor) and the drive circuit 1203 is the first wiring layer which is the lowest wiring layer as it is in FIGS. The power supply lines 1105 and 1205 and the GND lines 1110 and 1210 are electrically separated from each other.

  Reference numeral 1206 denotes a wiring connecting the power supply lines 1105 and 1205 and the heater 1101 and is connected directly to each wiring layer of the power supply line from the third layer wiring on which the heater is formed or through a through hole. Reference numeral 1207 denotes a wiring connecting the heater 1101 and the drain of the transistor 1102, and is connected through a through hole from the third layer wiring where the heater is formed to the first layer wiring where the drain electrode of the transistor 1102 is formed. Reference numeral 1208 denotes a wiring connecting the source of the transistor 1102 and the GND lines 1110 and 1210, and is connected to each wiring layer of the GND line from the first layer wiring in which the source electrode of the transistor 1102 is formed through through holes. Reference numeral 1209 denotes a wiring connecting the gate of the transistor 1102 and the driver circuit 1203, and is directly connected to the signal line of the driver circuit 1203 from the first layer wiring in which the gate electrode of the transistor 1102 is formed.

  According to the configuration of the present invention, there are roughly two effects: an effective wiring area expansion effect by forming two wiring layers, and an individual wiring area width reduction effect by configuring the wiring film thickness in two types.

  First, the effect of the two wiring layers will be described. With the configuration of the present invention, the power supply line and the GND line can be made to have two wiring layers with respect to one wiring layer of the conventional example 2, which is twice the wiring width of the conventional wiring. This is to obtain the same effect as the above, and to reduce the wiring resistance to ½. This effect is very effective as a means for reducing the wiring resistance without increasing the width of the wiring region.

  Particularly in response to the recent demand for high image quality and high-speed printing, it is common to increase the number of heaters in the substrate as the substrate for the recording head. However, this leads to the extension of the heater array in the substrate, the wiring resistance of the power supply line and the GND line increases, and the voltage drop from the power supply voltage increases, leading to a reduction in power efficiency. In order to avoid the above problem, the wiring width is generally increased. On the other hand, for the transistors and drive circuits directly under the wiring, the increase in the heater row generally leads to an increase in the length of the transistor and drive circuit area in the substrate in the heater row direction, but the width in the heater row direction. Does not lead to an increase in This means that there is a difference in width between the wiring that leads to the increase in width and the transistor and driving circuit area directly underneath that does not.

  In the conventional printhead substrate disclosed in Japanese Patent Laid-Open No. 8-108536, the fact that the wiring width and the transistor and drive circuit area just below the wiring width are substantially equal to each other is formed into upper and lower multilayers. The miniaturization is realized. In view of the characteristics, the present invention is characterized by further dividing the wiring width that hinders the miniaturization of the substrate into multiple layers.

  Next, the effect of configuring the wiring film thickness with two types will be described. The configuration of the present invention makes it possible to configure the power source line and the GND line of the individual wiring with two kinds of wiring film thicknesses, and the wiring resistance value adjustment means has conventionally been only the wiring width. Adjustment by film thickness is also possible. This gives a large degree of freedom to the adjustment of the wiring resistance value of the individual wiring.

  Short individual wiring not only narrows the wiring width to adjust in the direction of high resistance, but also can reduce the wiring film thickness, and long individual wiring not only increases the wiring width in the direction of low resistance but also wiring The film thickness can be increased. As a result, to reduce the size of the substrate, the transistor area and the power supply wiring area are overlapped, and the limit of the individual wiring area width generated by the overlap of the drive circuit area and the ground wiring area is kept as it is. The number of possible individual wirings can be increased. As a result, the number of heaters can be increased, and high-quality high-speed printing that is higher than conventional ones is realized.

  A method of making the wiring layer into two layers paying attention to the same problem is disclosed in Japanese Patent Laid-Open No. 10-181022. This configuration is characterized in that the power supply line and the GND line are formed in different wiring layers and overlapped irrespective of the transistor area and the drive circuit area immediately below the wiring, and is different from the present invention.

  The present invention also has the following features. Since the substrate that is an electrical circuit in the inkjet recording head substrate is in contact with the ink (specifically, it is in contact with the electrically insulating property), the ink can be electrophoresed by electric leakage or bias application. Of most concern. This is because a failure may occur due to a decrease in reliability due to a defect or the like. In the print head substrate, the layout of the power supply line is an item that is most concerned about the insulation and the influence of bias application to the periphery. However, the present invention is not different from the conventional example in terms of layout. Since the power supply line is arranged in the structure, characteristics equivalent to those of the conventional example can be obtained in insulation and bias characteristics.

  According to the present embodiment, the power supply line and the GND line are configured by the second and third wiring layers, but the present invention is not limited thereto, and is configured by a plurality of wiring layers other than the lowest wiring layer. It is possible. A feature of the present invention is that a plurality of power supply lines are formed above the transistors and a plurality of GND lines are formed above the drive circuit.

If the characteristics of the present invention are understood, the thickness of the wiring layer is not changed with the single-layer wiring structure according to the conventional example 1 using the common wiring as the power line and the GND line instead of the multi-layer wiring structure according to the embodiment of the present invention. It is common to increase the thickness only to a desired thickness. However, the thickness of the wiring layer in this case has a limit of about several μm. This is due to the reliability of the inorganic insulating layer made of SiO ₂ or the like used for insulating the wiring layer. As long as it is limited to the uppermost wiring layer on the substrate, it is possible to reduce the wiring layer to about several tens of μm by a method of insulating the wiring by using an organic insulating layer made of resin or the like and ensuring reliability. However, in this case, since the organic insulating layer of the uppermost layer wiring is a resin layer that also forms the flow path wall of the recording head necessary for ink jet ejection, the moldability, resistance to ink, and inorganic and organic materials that constitute the substrate New characteristics such as adhesion are required.

  FIG. 3 is a diagram showing a layout of a recording head substrate in Embodiment 2 of the present invention. FIG. 2 of Example 1 shows an example of an edge shooter type ink jet recording head substrate, whereas FIG. 3 shows an example of a side shooter type ink jet recording head substrate. 4 is a schematic cross-sectional view and a perspective view of the substrate taken along the line a-a ′ of FIG. According to this example, the heater 1101 is formed in the third wiring layer, but this is an example for explanation, and the present invention is not limited thereto. 3 has the same reference numerals as those in FIG. 2, so only the features peculiar to the second embodiment will be described, and the description of other parts identical to those in the first and second embodiments will be omitted. FIG. 8 and FIG. 9 are a layout diagram and a schematic sectional view of Conventional Example 3 corresponding to Example 2. FIG.

  With reference to FIG. An ink supply port 1121 for supplying ink from below the substrate is provided on the recording head substrate 1000, and a heater (heater array) 1101 (1201), a transistor (transistor array) 1102, and a drive circuit (drive circuit array) 1203 at both ends thereof. Are arranged sequentially. Characteristic features 1105 and 1205 of the present invention are power supply lines for applying a predetermined voltage to the heater 1101, and 1110 and 1210 are GND lines for grounding the heater 1101 via the transistor 1102. The power supply line 1105 is a wiring formed in the second wiring layer, and is formed above the transistor 1102 via an insulating layer. The power supply line 1205 is a wiring formed in the third wiring layer, It is formed above the line 1105 via an insulating layer. Similarly, the GND line 1110 is a wiring formed in the second wiring layer, and is formed above the drive circuit 1203 via an insulating layer. The GND line 1210 is a wiring formed in the third wiring layer. Yes, and formed above the GND line 1110 via an insulating layer. The power supply line and the GND line each have a power supply electrode pad 1111 and a GND electrode pad 1112 on the substrate as external electrical connection terminals.

  The third wiring layer is thicker than the second wiring layer, the second wiring layer is thinner than the third wiring layer, and the power line 1105 using the third wiring layer is connected to the heater array from the power electrode pad 1111. Used for longer individual wiring extending to the central portion, and the power line 1205 using the second wiring layer is used for shorter individual wiring extending from the power supply electrode pad 1111 to the end portion of the heater array, and is combined with the wiring width for each individual wiring. The GND line 1110 is composed of a power supply line in which the wiring resistance of the wiring is adjusted to be substantially equal, and the GND line 1110 using the third wiring layer is used for a longer individual wiring extending from the GND electrode pad 1112 to the central portion of the heater array. The GND line 1210 is used for shorter individual wiring extending from the GND electrode pad 1112 to the end of the heater array, and the wiring resistance of each individual wiring is combined with the wiring width. It is composed of a GND line which is substantially equal adjust.

2A and 2B are a layout view and a schematic cross-sectional view of a recording head substrate showing the features of the present invention. FIG. 2 is a layout diagram of a recording head substrate in Embodiment 1 of the present invention. FIG. 6 is a layout diagram of a recording head substrate in Embodiment 2 of the present invention. FIG. 4 is a schematic cross-sectional view taken along line a-a ′ shown in FIGS. FIG. 10 is a layout diagram of a recording head substrate in Conventional Example 1 (edge common wiring). It is a schematic cross section along the a-a 'line shown in FIG. FIG. 10 is a layout diagram of a recording head substrate in Conventional Example 2 (edge individual wiring). FIG. 10 is a layout diagram of a recording head substrate in Conventional Example 3 (side individual wiring). It is a schematic cross section along the a-a 'line shown in Drawings 7-8 of a conventional example. FIG. 3 is a diagram illustrating a circuit configuration of a recording head substrate. 11 is a timing chart for driving the circuit shown in FIG. 10. FIG. 3 is a perspective view illustrating an example of an edge shooter type recording head according to the present invention. It is a perspective view showing an example of a side shooter type recording head of the present invention. It is explanatory drawing which shows an example of the recording device of this invention.

Explanation of symbols

102 Carriage 103 Guide shaft 104 Main scanning motor 105 Motor pulley 106 Driven pulley 107 Timing belt 108 Recording medium 109 Conveying roller 130 Home position sensor 131 Pickup roller 132 Auto sheet feeder (ASF)
133 Paper end sensor 134 LF motor 135 Paper feed motor 136 Shield plate 181 Printhead substrate 182 Cover plate 183 Ink supply port 184 Flow path wall 191 Printhead substrate 192 Orifice plate 193 Ink supply pipe 194 Discharge port 195 Flow path wall 1000 Printhead substrate 1101 Thermal conversion element (heater)
1102 Transistor (transistor row region)
1103 Latch circuit 1104 Shift register 1105 Power line (by second wiring layer) 1106 Image data input terminal 1107 Transfer clock input terminal 1108 Latch signal input terminal 1109 Switch 1110 GND line (by second wiring layer) 1111 Power supply electrode pad 1112 GND Electrode pad 1121 ink supply port 1201 heater array (heater array area)
1203 Drive circuit (drive circuit array region)
1205 Power supply line (by the third wiring layer) 1206 Wiring connecting the power supply line and the heater 1207 Wiring connecting the heater and the transistor (drain) 1208 Wiring connecting the transistor (source) and the GND line 1209 Wiring connecting the transistor (gate) and the drive circuit 1210 GND line H1000 (by third wiring layer) printhead cartridge

Claims (6)

A heat conversion element array for applying energy for ejecting the recording liquid, a transistor array for operating the heat conversion element, and a drive circuit array for driving the transistor by an input signal are sequentially arranged. The transistor and the drive circuit In the substrate that is wired using the first wiring layer that is the lowermost wiring layer,
A power supply wiring for supplying power to the heat conversion element is formed in a plurality of wiring layers other than the lowest wiring layer with an insulating layer interposed between the transistors in a region including a part or all of the transistor row region. In the region including a part or all of the drive circuit array region, the ground wiring of the thermal conversion element through the transistor includes a plurality of layers other than the lowermost wiring layer with an insulating layer sandwiched between the drive circuits. The thermal conversion element array, the power supply wiring group, and the ground wiring group are sequentially aligned, and
A plurality of wiring layers other than the lowermost wiring layer have different film thicknesses;
The power supply wiring and the ground wiring have a plurality of divided wirings having substantially the same wiring resistance in the same and different wiring layers;
The power supply wiring and the ground wiring have a divided wiring in which a long wiring uses a thick wiring layer, a short wiring uses a thin wiring layer, and wiring resistances are formed almost equal to each other. .   In the substrate, the long wiring of the power supply wiring and the ground wiring is a long wiring connected to the heat conversion element near the center of the substrate, and the short wiring is a short wiring connected to the heat conversion element near the edge of the substrate. The recording head according to claim 1.   In the substrate, the power supply wiring is formed in a region including a part or all of the transistor array region by a second wiring layer and a third wiring layer on an upper side of the transistor with an insulating layer interposed therebetween. The ground wiring of the heat conversion element is formed by the second and third wiring layers with an insulating layer interposed between the drive circuit in a region including a part or all of the drive circuit row region. The recording head according to claim 1, wherein the recording head is a recording head.   4. The recording head according to claim 1, wherein the substrate includes a supply port for supplying a recording liquid and an ejection port forming member that forms an ejection port for ejecting the recording liquid. 5. .   The recording head according to claim 1, wherein the wiring layer is made of aluminum, copper, gold, or an alloy containing aluminum, copper, or gold.   A recording apparatus comprising the recording head according to claim 1.

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