JP2009208443A - Liquid jetting head and liquid jetting apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid jetting head capable of detecting temperature at a position nearer to a nozzle opening, and to provide a liquid jetting apparatus equipped with the same. <P>SOLUTION: Head units 11 are each provided with a temperature sensor 58. This temperature sensor is composed of a temperature sensitive part 59 comprising for example a thermocouple and sensing temperature and of a wiring part 60 electrically connecting between the temperature sensitive part 59 and a temperature detection circuit 78. In the present embodiment, a sensor housing part 61 is formed by making a recess to the opposite side in a part of a joint face with a nozzle forming substrate 35 of a flow channel forming substrate 45, with the temperature sensitive part housed in the sensor housing part in a state in contact with the nozzle forming substrate. In other words, a temperature detecting means is arranged adjacently to the back on the side opposite from the face of the inkjetting side of the nozzle forming substrate. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a liquid ejecting head such as an ink jet recording head and a liquid ejecting apparatus, and more particularly to a liquid ejecting head including a temperature detecting unit and a liquid ejecting apparatus.

  For example, a liquid ejecting apparatus is an apparatus that includes a liquid ejecting head capable of ejecting liquid and ejects various liquids from the liquid ejecting head. As a typical example of this liquid ejecting apparatus, for example, an ink jet recording head (hereinafter simply referred to as a recording head) as a liquid ejecting head is provided, and liquid ink is ejected from the recording head nozzle opening to a recording medium such as recording paper. An image recording apparatus such as an ink jet printer that records an image or the like by forming dots by ejecting and landing on the (ejection target) can be exemplified. In recent years, liquid ejecting apparatuses have been applied not only to this image recording apparatus but also to various manufacturing apparatuses such as a manufacturing apparatus for color filters such as liquid crystal displays.

  By the way, in the above-described printer, when an image or the like is recorded / printed on a recording medium, in particular, a recording paper, there is a possibility that the recording paper may be distorted or uneven or the recorded image may be blurred due to moisture contained in the ink. In particular, when different colors are mixed due to bleeding, the image quality of the recorded image may be deteriorated. In order to cope with such a problem, a configuration has been proposed in which a heating unit (heat source) for heating the recording paper is provided, and drying of the ink landed on the recording paper is promoted by heating the recording paper by the heating unit (for example, , See Patent Document 1).

JP 2001-287455 A

  However, in the configuration in which the recording paper is heated by the heating means, the temperature of the nozzle forming substrate of the recording head may also rise. Then, as the temperature of the nozzle forming substrate rises, the viscosity of the ink near the nozzle opening rises, and the viscosity changes (decreases). As a result, there is a possibility that the ejection characteristics such as the amount of ink ejected from the nozzle opening and the flying speed may fluctuate.

  Some conventional printers detect the temperature around the recording head and correct the drive signal for driving the pressure generating means based on the detected temperature. The temperature of the ink in the vicinity of the nozzle opening cannot be accurately measured because the means for detecting the ink is provided at a position away from the nozzle opening.

  SUMMARY An advantage of some aspects of the invention is that it provides a liquid ejecting head capable of detecting a temperature at a position closer to a nozzle opening and a liquid ejecting apparatus including the liquid ejecting head. There is to do.

The liquid ejecting head of the present invention is proposed to achieve the above object, and includes a nozzle forming substrate in which nozzle openings are arranged, and is a liquid ejecting head that ejects liquid from the nozzle openings,
A temperature detecting means for detecting the temperature inside the liquid ejecting head is provided;
The temperature detecting means is disposed adjacent to the nozzle forming substrate.

  According to this configuration, since the temperature detection unit is disposed adjacent to the nozzle forming substrate, it is possible to detect the temperature at a position closer to the nozzle opening than in the prior art. Thereby, it becomes possible to improve the accuracy of control based on the detected temperature.

In the above configuration, the nozzle forming substrate has a nozzle group in which a plurality of nozzle openings are arranged for each type of liquid,
It is possible to adopt a configuration in which the temperature detecting means is individually arranged for each nozzle group of the same type.
In this configuration, it is desirable that the temperature detecting means is disposed between adjacent nozzle groups along the direction in which the nozzle openings are arranged.

  According to the above configuration, since the temperature detecting means is individually provided for each nozzle group of the same type, a more accurate temperature can be detected for each liquid type.

In the above configuration, the nozzle forming substrate has a nozzle group in which a plurality of nozzle openings are arranged for each type of liquid,
It is also possible to adopt a configuration in which one temperature detection means is arranged in series in common for all nozzle groups.
In this configuration, it is possible to employ a configuration in which the temperature detection means is arranged in a meandering manner so as to pass through a pair of adjacent nozzle groups.
Further, in the above configuration, it is possible to employ a configuration in which the temperature detection unit is disposed in a state of surrounding all the nozzle groups.

  According to this configuration, since one temperature detection unit is arranged in series for all the nozzle groups, the circuit can be simplified. Moreover, it becomes possible to contribute to cost reduction.

  In each of the above configurations, it is desirable to employ a configuration in which the temperature detecting means is disposed adjacent to the back surface of the nozzle forming substrate opposite to the liquid jet side surface.

  According to this configuration, the temperature detection unit is disposed adjacent to the back surface of the nozzle formation substrate opposite to the liquid ejection side surface, so that the temperature detection unit protrudes from the liquid ejection side surface of the nozzle formation substrate. Therefore, when the wiping member is slidably brought into contact with the liquid ejection side surface of the nozzle forming substrate, the temperature detecting means can be prevented from coming into contact with the wiping member. In addition, since the distance between the surface on the liquid ejection side and the ejection object is not increased, it is possible to maintain the liquid landing accuracy on the ejection object.

And the liquid ejecting apparatus of the present invention includes a liquid ejecting head having the above-described configuration,
Heating means for heating the injection target;
Drive signal generating means for generating a drive signal for driving the pressure generating means;
Drive signal correction means for correcting the drive signal generated from the drive signal generation means based on the temperature detected from the temperature detection means disposed in the liquid jet head;
It is characterized by providing.

  The best mode for carrying out the present invention will be described below with reference to the drawings. In the embodiments described below, various limitations are made as preferred specific examples of the present invention. However, the scope of the present invention is not limited to the following description unless otherwise specified. However, the present invention is not limited to these embodiments. In the present embodiment, an image recording apparatus that is one form of the liquid ejecting apparatus, and more specifically, a length corresponding to the maximum recording width of the recording paper that becomes the ejection target (or recording medium) at equal intervals in the nozzle aperture group. An ink jet printer (hereinafter simply referred to as a printer) equipped with a long line type liquid ejecting head (hereinafter referred to as a line head) arranged as an example will be described as an example.

  FIG. 1 is a partially broken perspective view illustrating a schematic configuration of a printer 1 according to the present invention. The printer 1 of the present embodiment includes a line head 3 (broadly defined liquid ejecting head) configured by arranging a plurality of head units 11 (narrowly defined liquid ejecting heads) in a staggered manner inside a housing 2; A paper feed tray 5 that stores the recording paper 4 in a stacked state, and a paper feed unit 6 that feeds the recording paper 4 one by one from the paper feed tray 5 and supplies it to the downstream side (conveying unit 7 side) of the line head 3. A transport unit 7 that transports the recording paper 4 supplied by the paper feed unit 6; and a drying assist unit 8 that heats the recording surface of the recording paper 4 on which recording is performed by the line head 3 to promote ink drying. (A kind of heating means in the present invention), a discharge section 9 for discharging the recording paper 4 recorded by the line head 3, and a discharge tray 10 for holding the recording paper 4 discharged from the discharge section 9. Recording without scanning the line head 3 It is configured to be able to record text or images, etc. to the full width of the fourth recording area.

  Although not shown, an ink cartridge (a type of liquid supply source) that stores ink is disposed inside the housing 2. The ink stored in the ink cartridge is supplied (pressure-fed) to each head unit 11 of the line head 3 through the ink supply tube by pressurizing the ink cartridge by an air pump or the like.

  In the housing 2, a recording position that is an area above the transport unit 7 and in which the line head 3 ejects ink to record (print) an image or the like on the recording paper 4, and the line head 3. A standby position (home position) is set in which when the camera does not record, it waits out of the recording position. The line head 3 is movably supported by a guide shaft 12 extending over the recording position and the standby position, and the standby position along the guide shaft 12 is actuated by the operation of the head moving mechanism 76 (see FIG. 6). And the recording position.

  At the standby position, a capping mechanism 15 having a cap 14 for sealing the nozzle formation surface (nozzle formation substrate 35; see FIG. 2 and the like) of each head unit 11 of the line head 3 is disposed. The capping mechanism 15 has a plurality of tray-like caps 14 made of an elastic member such as an elastomer corresponding to each head unit 11 of the line head 3. Then, the capping mechanism 15 advances (rises) toward each nozzle formation surface of the line head 3 that has moved to the standby position, and seals each cap 14 against the nozzle formation surface of the corresponding head unit 11 by pressing. Stop. By sealing the nozzle forming surface with the cap 14, it is possible to prevent the ink solvent from evaporating from the nozzle openings 33 (see FIG. 3 and the like) and to suppress the increase in the viscosity of the ink. The capping mechanism 15 has a wiping member (not shown) for wiping the nozzle forming surface of the head unit 11. The wiping member is made of, for example, an elastic material such as rubber or elastomer, and wipes ink or the like adhering to the nozzle formation surface by slidingly contacting the nozzle formation surface.

  The paper feed unit 6 includes a pickup roller 16, a pair of upper and lower feed rollers 17 a and 17 b, and an endless feed belt 20 that is stretched over a drive roller 18 and a driven roller 19. A pickup roller 16 that is rotationally driven by a motor (not shown) rotates in contact with the uppermost one of the recording paper 4 set in the paper feeding tray 5, thereby removing the uppermost recording paper 4 from the paper feeding tray 5. Pull out. The feeding rollers 17a and 17b feed the uppermost recording paper 4 fed from the paper feeding tray 5 to the feeding belt 20 one by one in a nipped state. The driving roller 18 is rotated by a rotation driving source (not shown) to drive the feeding belt 20 and to feed the recording paper 4 placed on the feeding belt 20 to the conveying unit 7 on the downstream side. It is configured.

  The transport unit 7 includes a transport belt 24 spanned by the transport drive roller 22 and the transport driven roller 23, guide plates 25a and 25b (platens) divided into two on the upstream side and the downstream side, and these guide plates. The heating guide plate 26 is disposed between 25a and 25b and functions as a kind of heating means for heating the recording paper 4 on the conveying belt 24 while also functioning as a guide plate. The conveyance drive roller 22 is rotated in synchronization with the recording operation of the line head 3 by a rotation drive source (not shown), thereby driving the endless conveyance belt 24, and the recording paper fed from the paper supply unit 6. 4 is configured to pass below the line head 3 and to be conveyed to the discharge unit 9 side.

  The guide plates 25a and 25b are disposed inside the conveyor belt 24, and support the recording paper 4 on the conveyor belt from the back side of the conveyor belt 24 so as to be parallel to the nozzle formation surface of the line head 3. It has become. Similar to the guide plates 25 a and 25 b, the heating guide plate 26 is disposed inside the conveyance belt 24 and supports the recording paper 4 on the conveyance belt from the back side of the conveyance belt 24. The heating guide plate 26 includes a heat source (not shown), and is configured to heat the recording paper 4 on which the recording operation is performed by the line head 3 from the back side.

  The line head 3 moves from the standby position to the recording position while being guided by the guide shaft 12 when performing the recording operation, stops at this recording position, and makes the nozzle formation surface face the recording paper 4 on the transport belt 24. In this state, the recording operation is performed by ejecting ink from the nozzle openings 33 to the recording paper 4. At this time, since the recording paper 4 is heated by the heating guide plate 26, evaporation of the solvent of the ink that has landed on the recording surface of the recording paper 4 is promoted by this heat, thereby shortening the drying time of the ink. Can do.

  The discharge unit 9 includes a discharge belt 30 that is rotated by a rotation drive source (not shown) and a discharge driven roller 29, and a discharge guide plate 31. The discharge drive roller 28 drives the discharge belt 30 by being rotated by a rotation drive source. The discharge belt 30 conveys the recording paper 4 on which an image or the like has been recorded on the recording position side to the downstream side and discharges it to the paper discharge tray 10. A drying assist unit 8 is disposed above the discharge belt 30. The drying assist unit 8 is configured to further heat the drying of ink landed on the recording surface of the recording paper 4 by heating the recording paper 4 sent from the recording position side.

  FIG. 2 is a plan view showing the configuration of the line head 3 in the present embodiment, as viewed from the nozzle forming surface side. As shown in the figure, the line head 3 has a plurality of head units 11 arranged in a zigzag pattern in two stages in a direction perpendicular to the conveyance direction of the recording paper 4 (up and down direction in FIG. 2) and attached to the base portion 34. The nozzle opening 33 of the head unit 11 is disposed in a length that can correspond to the maximum recording width of the recording paper 4 as a whole. The base portion 34 is movably attached to the guide shaft 12, and the line head 3 moves between the standby position and the recording position by moving the base portion 34 along the guide shaft 12 by a head moving mechanism (not shown). It has come and goes between.

  FIG. 3 is a cross-sectional view of a main part for explaining the configuration of the head unit 11. The head unit 11 includes a head case 37, a vibrator unit 38 housed in the head case 37, a flow path unit 39 joined to the bottom surface (tip surface) of the head case 37, and the like.

  The head case 37 is made of, for example, an epoxy resin, and an accommodation space 41 for accommodating the vibrator unit 38 is formed therein. The vibrator unit 38 includes a piezoelectric vibrator 42 that functions as a kind of pressure generating means, a fixing plate 43 to which the piezoelectric vibrator 42 is joined, and a flexible cable 44 for supplying a drive signal and the like to the piezoelectric vibrator 42. And. The piezoelectric vibrator 42 is a laminated type manufactured by cutting a piezoelectric plate in which piezoelectric layers and electrode layers are alternately laminated into a comb-like shape, and can be expanded and contracted in a direction perpendicular to the lamination direction. This is a piezoelectric vibrator.

  A circuit board (not shown) is attached to the base end surface (upper surface) of the head case 37. This circuit board receives a drive signal from a drive signal generation circuit 73 (see FIG. 6) of the printer body, and supplies a drive signal for supplying this drive signal to the piezoelectric vibrator 42 of the vibrator unit 38 through the flexible cable 44. It is a board to relay. The circuit board is provided with a temperature detection circuit 78 (see FIG. 6), which is connected to a temperature sensor unit 58, which will be described later, and outputs temperature detection information corresponding to the detected temperature (thermal electromotive force) of the temperature sensor unit 58. ing.

  The channel unit 39 is configured by joining a nozzle forming substrate 35 to one surface of the channel forming substrate 45 and a diaphragm 46 to the other surface of the channel forming substrate 45. The flow path unit 39 is provided with a reservoir 47 (liquid chamber), an ink supply port 48, a pressure generation chamber 49, and a nozzle opening 33. A series of ink flow paths (liquid flow paths) from the ink supply port 48 to the nozzle opening 33 through the pressure generation chamber 49 are formed corresponding to each nozzle opening 33.

  The diaphragm 46 has a double structure in which an elastic film 52 is laminated on the surface of the support plate 51. In the present embodiment, a stainless plate, which is a kind of metal plate, is used as the support plate 51, and the vibration plate 46 is formed using a composite plate material in which a resin film is laminated as an elastic film 52 on the surface of the support plate 51. The diaphragm 46 is provided with a diaphragm 53 that changes the volume of the pressure generating chamber 49. The diaphragm 46 is provided with a compliance portion 54 that seals a part of the reservoir 47.

  The diaphragm 53 is produced by partially removing the support plate 51 by etching or the like. That is, the diaphragm portion 53 includes an island portion 55 to which the distal end surface of the free end portion of the piezoelectric vibrator 42 is joined, and a thin elastic portion around the island portion 55. The compliance portion 54 is produced by removing the support plate 51 in the region facing the opening surface of the reservoir 47 by etching processing or the like in the same manner as the diaphragm portion 53, and reduces the pressure fluctuation of the liquid stored in the reservoir 47. Functions as a damper to absorb.

  Since the tip surface of the piezoelectric vibrator 42 is joined to the island portion 55, the volume of the pressure generating chamber 49 can be changed by expanding and contracting the free end portion of the piezoelectric vibrator 42. As the volume changes, pressure fluctuations occur in the ink in the pressure generating chamber 49. The head unit 11 ejects ink from the nozzle openings 33 using this pressure fluctuation.

  The nozzle forming substrate 35 is made of a metal plate such as stainless steel. As shown in FIG. 2, the nozzle formation substrate 35 of each head unit 11 has a plurality of nozzle openings 33 for ejecting ink (a kind of liquid in the present invention) arranged in a direction orthogonal to the conveyance direction of the recording paper 4. A nozzle row 36 (a kind of nozzle group) is configured, and a plurality of nozzle rows 36 are formed in the recording paper conveyance direction. One nozzle row 36 in the present embodiment is composed of 180 nozzle openings 33 which are opened at a pitch of 180 dpi. In the head unit 11, two nozzle rows 36 correspond to each ink type, that is, each ink color. In the present embodiment, it corresponds to four colors of ink, cyan ink (C), magenta ink (M), yellow ink (Y), and black ink (K). Therefore, in the present embodiment, a total of eight nozzle rows 36 are formed side by side in the transport direction. The two nozzle rows 36 of the same color are arranged in a state where the positions are relatively shifted in the nozzle row setting direction so that the pitch of the adjacent nozzle rows 36 and the nozzle openings 33 in the nozzle row setting direction is 360 dpi. Has been. Accordingly, one head unit 11 has a total of 360 nozzle openings 33 arranged in a staggered pattern for each ink color at a pitch of 360 dpi when viewed in a direction orthogonal to the recording sheet conveyance direction (recording sheet width direction).

  As shown in FIG. 2, each head unit 11 is arranged on the base portion 34 in a staggered manner at intervals such that the nozzle openings 33 are arranged at 360 dpi as a whole when viewed in a direction orthogonal to the recording paper conveyance direction. Has been. The number of the head units 11 provided is determined according to the maximum recording width of the recording paper 4.

  Here, each head unit 11 is provided with a temperature sensor 58 (a kind of temperature detecting means in the present invention). The temperature sensor unit 58 includes, for example, a thermocouple, and includes a temperature sensing unit 59 that senses temperature, and a wiring unit 60 that electrically connects the temperature sensing unit 59 and the temperature detection circuit 78. Yes. In this embodiment, a part of the bonding surface of the flow path forming substrate 45 with the nozzle forming substrate 35 is recessed on the opposite surface side (the bonding surface side with the diaphragm 46) to form the sensor housing portion 61, and the nozzle The temperature sensitive part 59 is accommodated in the sensor accommodating part 61 in a state of being in contact with the formation substrate 35 and is fixed with a heat conductive adhesive containing metal particles. That is, the temperature detecting means is disposed adjacent to the back surface of the nozzle forming substrate 35 opposite to the ink ejecting surface. In addition, the flow path forming substrate 45, the diaphragm 46, and the head case 37 are formed with wiring accommodating portions 62 that pass through these thickness directions (height directions) and communicate in series. One end portion (lower end portion) of the wiring housing portion 62 communicates with the sensor housing portion 61, and the other end portion (upper end portion) opens on the upper surface of the head case 37 and communicates with the circuit board side. The wiring portion 60 is passed through the wiring housing portion 62, and the end portion (terminal portion) of the wiring portion 60 on the side opposite to the temperature sensing portion 59 is connected to the temperature detection circuit 78.

  FIG. 4 is a plan view of the flow path forming substrate 45 for explaining the arrangement state of the temperature sensor unit 58, and FIG. 5 is a cross-sectional view taken along line AA in FIG. As described above, the head unit 11 in this embodiment is provided with two nozzle rows corresponding to each ink color. That is, the nozzle row 36 (C) corresponding to cyan ink, the nozzle row 36 (M) corresponding to magenta ink, the nozzle row 36 (Y) corresponding to yellow ink, and the nozzle row 36 (K) corresponding to black ink. A total of eight nozzle rows 36 are arranged side by side in the conveyance direction of the recording paper. And in this embodiment, the temperature sensor part 58 is separately arrange | positioned for every nozzle row of the same color. Specifically, it is an area between adjacent nozzle rows 36 of the same color and is slightly longer than the nozzle row at a position outside the ink flow path such as the pressure generation chamber 49 formed on the flow path forming substrate 45. A long sensor housing 61 is formed, and a temperature sensing portion 59 is housed in the sensor housing 61 and arranged along the nozzle row.

  As shown in FIGS. 4 and 5, a wiring housing portion 62 is formed on one side (right side in FIGS. 4 and 5) of the sensor housing portion 61 in the nozzle row direction and passes through the wiring portion 60. Then, a temperature sensing unit 59 is laid along one nozzle row of the adjacent nozzle rows from one side of the sensor housing portion 61 to the other side (left side in FIGS. 4 and 5), and the other end of the sensor housing portion 61. A junction point J of the thermocouple is disposed in the part, and the temperature sensing part 59 is disposed along the other nozzle row toward the one side of the sensor housing part 61 by folding back at the junction point J, thereby The warming part 59 reciprocates in the area between the nozzle rows.

  Thus, since the temperature sensing part 59 of the temperature sensor part 58 is disposed adjacent to the nozzle forming substrate 35, the temperature at a position closer to the nozzle opening 33 can be detected by the temperature sensing part 59. Further, since the temperature sensor unit 58 is individually provided for each nozzle row of the same type (same color), it is possible to detect the temperature as accurate as possible for each ink color. Further, since the temperature sensing unit 59 of the temperature sensor unit 58 is disposed adjacent to the back surface of the nozzle forming substrate 35 opposite to the surface on the ink ejection side, the temperature sensor unit 58 ejects ink from the nozzle formation substrate 35. Therefore, the temperature sensor unit 58 is prevented from coming into contact with the wiping member when the wiping member is slidably brought into contact with the ink ejection side surface of the nozzle forming substrate 35. be able to. Further, since the distance between the ink ejection side surface and the recording paper 4 is not increased, the ink landing accuracy on the recording paper 4 can be maintained.

Next, the electrical configuration of the printer 1 will be described.
FIG. 6 is a block diagram illustrating an electrical configuration of the printer 1. The printer 1 according to the present embodiment is schematically configured by a printer controller 65 and a print engine 66. The printer controller 65 stores an external interface (external I / F) 67 for receiving print data from an external device such as a host computer, a RAM 68 for storing various data, and a control program for various controls. A ROM 69, a nonvolatile storage element 70 such as an EEPROM or a flash ROM, a control unit 71 that performs overall control of each unit in accordance with a control program stored in the ROM 69, an oscillation circuit 72 that generates a clock signal, A drive signal generation circuit 73 (a type of drive signal generation means) that generates a drive signal to be supplied to each head unit 11 of the line head 3, and dot pattern data and drive signals obtained by developing print data for each dot Etc. to output to the head unit 11 internal interface (internal I / F) And a 4.

  The print engine 66 includes a plurality of head units 11 constituting the line head 3, a head moving mechanism 76, and a paper feed mechanism 77 including a paper feed unit 6, a transport unit 7, and a discharge unit 9. The print engine 66 includes a temperature detection circuit 78 to which the temperature sensor unit 58 is connected. The temperature detection circuit 78 is configured to A / D convert the detection signal of the temperature sensor unit 58 and output it to the control unit 71 as temperature detection information.

The drive signal generation circuit 73 generates a drive signal COM having a predetermined waveform.
FIG. 7 shows an example of a drive pulse included in the drive signal COM. The illustrated drive pulse DP includes an expansion element P1 that increases the potential with a constant gradient that does not cause ink to be ejected from the intermediate potential VM to the first maximum potential VH, an expansion hold element P2 that holds the maximum potential VH for a predetermined time, An injection element P3 for decreasing the potential steeply from the potential VH to the minimum potential VL, a vibration suppression hold element P4 for holding the minimum potential VL for a predetermined time, and a vibration suppression element P5 for increasing the potential from the minimum potential VL to the intermediate potential VM It consists of and.

  When the drive pulse DP configured in this way is supplied to the piezoelectric vibrator 42, first, the piezoelectric vibrator 42 contracts in the element longitudinal direction by the expansion element P1, and the pressure generating chamber 49 corresponds to the intermediate potential VM. The volume expands to the expansion volume corresponding to the highest potential VH. Due to this expansion, the meniscus exposed to the nozzle opening 33 is largely drawn to the pressure generation chamber 49 side, and ink is supplied into the pressure generation chamber 49 from the reservoir 47 side through the ink supply port 48. The expanded state of the pressure generating chamber 49 is maintained over the supply period of the expansion hold element P2. Thereafter, the ejection element P3 is supplied and the piezoelectric vibrator 42 expands. By the extension of the piezoelectric vibrator 42, the pressure generating chamber 49 is rapidly contracted from the expansion volume to the contraction volume corresponding to the lowest potential VL. The ink in the pressure generation chamber 49 is pressurized by the rapid contraction of the pressure generation chamber 49, and the ink is ejected from the nozzle opening 33. The contraction state of the pressure generation chamber 49 is maintained over the supply period of the vibration suppression hold element P4. During this period, the ink pressure in the pressure generation chamber 49 that has decreased due to ink ejection rises again due to its natural vibration. The damping element P5 is supplied in accordance with the rising timing. By supplying the damping element P5, the pressure generating chamber 49 expands and returns to the reference volume, and the pressure fluctuation of the ink in the pressure generating chamber 49 is absorbed.

  Here, in the printer 1, the recording paper 4 is heated by the heating unit (the heating guide plate 26 and the drying assist unit 8) so as to accelerate the drying of the ink that has landed on the recording paper 4, thereby causing the vicinity of the nozzle forming substrate 35. The temperature rises. Along with this, the temperature of the ink in the vicinity of the nozzle opening 33 rises, so that the viscosity of the ink changes (decreases). As a result, when no countermeasures are taken, there is a possibility that the ejection characteristics such as the amount of ink ejected from the nozzle openings 33 and the flight speed fluctuate. For example, when the viscosity of the ink decreases, the amount of ink ejected from the nozzle opening 33 increases.

  Therefore, the control unit 71 functions as a drive signal correction unit in the present invention, and corrects the drive signal based on the temperature detected by the temperature sensor unit 58, that is, the temperature detection information from the temperature detection circuit 78. Specifically, the drive voltage Vh (potential difference between the lowest potential VL and the highest potential VH) of the drive pulse DP is corrected. That is, for example, when the temperature detected by the temperature sensor unit 58 rises above room temperature (for example, 25 ° C.), the drive voltage VH of the drive pulse DP is lowered below the reference value (set voltage at room temperature). . As a result, even when the viscosity of the ink decreases due to an increase in temperature, the amount of ink ejected from the nozzle opening 33 can be adjusted to an appropriate value, and fluctuations in ejection characteristics can be suppressed. In particular, since the temperature sensor 58 detects the temperature at a position closer to the nozzle opening 33, the accuracy of drive voltage correction based on the detected temperature can be improved. The correction of the drive signal is not limited to the correction of the drive voltage Vh of the drive pulse. For example, the generation time of each waveform element of the drive pulse and the correction of the intermediate potential VM may be performed. The correction of the drive signal may be adjusted in consideration of the balance between the ejected ink amount and the ink speed.

Next, another embodiment of the present invention will be described.
FIG. 8 is a plan view of the flow path forming substrate 45 for explaining the arrangement state of the temperature sensor unit 58 in the second embodiment, and FIG. 9 is a cross-sectional view taken along the line BB in FIG. In the second embodiment, one temperature sensor unit 58 (temperature sensing unit 59) is arranged in a meandering manner so as to pass through between the adjacent nozzle rows of the same color as a pair. It has the characteristics. With this configuration, one temperature sensor unit 58 is arranged in series for all the nozzle rows 36, so that the temperature detection circuit 78 can be simplified. In addition to this, it is possible to contribute to cost reduction.

  FIG. 10 is a plan view of the flow path forming substrate 45 for explaining the arrangement state of the temperature sensor unit 58 in the third embodiment, and FIG. 11 is a cross-sectional view taken along the line CC in FIG. The third embodiment is characterized in that one temperature sensor unit 58 (temperature sensing unit 59) is arranged so as to surround all the nozzle rows 36. That is, in the flow path forming substrate 45, a state of making a round around the outer peripheral edge portion outside the central area where the ink flow path such as the pressure generating chamber 49 is formed (specifically, since it reciprocates in the sensor housing portion 61). A temperature-sensing part 59 is laid in a state of two rounds. This third embodiment is suitable when the temperature sensitive part 58 cannot be disposed between nozzle rows in a configuration in which the interval between adjacent pairs of nozzles of the same color adjacent to each other is narrow.

  Regarding the heating means, in the above-described embodiment, the heating guide plate 26 that is disposed immediately below the line head 3 and heats the recording paper 4 being recorded, and the drying assist unit 8 that heats the recording surface after the recording is completed. However, the present invention is not limited to this. For example, the present invention is also suitable in a configuration in which preheating means for heating the recording paper 4 in advance before recording by the line head 3 is provided.

  In the above, the line head 3 mounted on a printer (a kind of liquid ejecting apparatus) is exemplified as the liquid ejecting head according to the present invention. However, the present invention can also be applied to other liquid ejecting heads. . For example, the present invention can be applied to a so-called serial type recording head that ejects ink while reciprocating in the width direction of the recording paper (direction orthogonal to the transport direction). In addition, color material ejection heads used for the production of color filters such as liquid crystal displays, electrode material ejection heads used for electrode formation such as organic EL (Electro Luminescence) displays, FEDs (surface emitting displays), biochips (biochemical elements) The present invention can also be applied to bioorganic matter ejecting heads and the like used in the production of

FIG. 2 is a perspective view illustrating a configuration of a printer. It is a top view which shows the structure of a line head. FIG. 3 is a cross-sectional view of a main part of the recording head. It is a top view of a flow path formation board. It is the sectional view on the AA line in FIG. 2 is a block diagram illustrating an electrical configuration of a printer. FIG. It is a wave form diagram explaining the structure of a drive pulse. It is a top view of a channel formation substrate in a 2nd embodiment. It is the BB sectional view taken on the line in FIG. It is a top view of a channel formation substrate in a 3rd embodiment. It is CC sectional view taken on the line in FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Printer, 3 ... Line head, 4 ... Recording paper, 8 ... Drying assistance part, 11 ... Head unit, 26 ... Heating guide plate, 33 ... Nozzle opening, 34 ... Base part, 35 ... Nozzle formation board, 36 ... Nozzle , 37 ... head case, 58 ... temperature sensor part, 59 ... temperature sensing part, 60 ... wiring part, 61 ... sensor housing part, 62 ... wiring housing part, 71 ... control part, 73 ... drive signal generating circuit, 78 ... Temperature detection circuit

Claims (8)

A nozzle forming substrate in which nozzle openings are arranged, and a liquid ejecting head that ejects liquid from the nozzle openings,
A temperature detecting means for detecting the temperature inside the liquid ejecting head is provided;
The liquid ejecting head, wherein the temperature detecting means is disposed adjacent to the nozzle forming substrate. The nozzle forming substrate has a nozzle group in which a plurality of nozzle openings are arranged for each type of liquid,
The liquid ejecting head according to claim 1, wherein the temperature detecting unit is individually arranged for each nozzle group of the same type.   The liquid ejecting head according to claim 2, wherein the temperature detecting unit is disposed between adjacent nozzle groups along a direction in which nozzle openings are arranged. The nozzle forming substrate has a nozzle group in which a plurality of nozzle openings are arranged for each type of liquid,
The liquid jet head according to claim 1, wherein one temperature detection unit is arranged in series for all nozzle groups.   5. The liquid jet head according to claim 4, wherein the temperature detection unit is arranged in a meandering manner so as to pass between all adjacent nozzle groups as a pair.   The liquid ejecting head according to claim 4, wherein the temperature detecting unit is disposed in a state of surrounding all the nozzle groups.   The liquid according to any one of claims 1 to 6, wherein the temperature detection unit is disposed adjacent to a back surface of the nozzle forming substrate opposite to a surface on the liquid ejection side. Jet head. A liquid jet head according to any one of claims 1 to 7,
Heating means for heating the injection target;
Drive signal generating means for generating a drive signal for driving the pressure generating means;
Drive signal correction means for correcting the drive signal generated from the drive signal generation means based on the temperature detected from the temperature detection means disposed in the liquid jet head;
A liquid ejecting apparatus comprising:

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