Liquid ejecting apparatus and liquid ejecting head

Abstract

The invention relates to a liquid ejecting apparatus and a liquid ejecting head. The liquid ejecting apparatus includes: a channel forming portion including an ejection opening through which liquid is ejected, a pressure chamber communicating with the ejection opening, and an independent channel communicating with the pressure chamber; a first energy generating element provided at a position corresponding to the pressure chamber of the channel forming portion, and generating energy for ejecting the liquid through the ejection opening; a second energy generating element that is provided at a position corresponding to the independent channel of the channel forming portion and generates energy for transferring the liquid through the independent channel; a temperature detection section configured to detect a temperature, and provided at a position corresponding to the first energy generation element or the second energy generation element; and a control section configured to control driving of the second energy generation element based on a detection result of the temperature detection section.

Description

Technical Field

[0001] This disclosure relates to a liquid injection device and a liquid injection head disposed on the liquid injection device. Background Technology

[0002] In liquid ejection heads used for ejecting liquids (such as ink), volatile components in the liquid may evaporate and increase the viscosity of the liquid around the ejection orifice. This increase in liquid viscosity can affect the ejection velocity and landing accuracy of the ejected droplets. One known measure to suppress this increase in liquid viscosity is cyclic drive operation, in which a very small circulating flow is generated within a separate channel including the ejection orifice.

[0003] WO 2016 / 068988 discloses a configuration that includes a fluid circulation element and is capable of executing a cyclic drive sequence for driving the fluid circulation element to circulate the fluid intermittently.

[0004] If the conditions and number of fluid circulation cycles are set to reliably address viscosity increases while considering deviations, the circulation rate may be over-set. Excessive circulation of liquid through the liquid nozzle may generate heat or thicken the liquid due to the driving of the circulation. Summary of the Invention

[0005] The present disclosure aims to provide a liquid injection device capable of suppressing excessive liquid circulation.

[0006] According to some embodiments, the liquid injection device of this disclosure is characterized by including the following structure:

[0007] The channel forming section includes a jet opening through which liquid is ejected, a pressure chamber communicating with the jet opening, and an independent channel communicating with the pressure chamber.

[0008] A first energy generating element is disposed at a position corresponding to the pressure chamber of the channel forming portion, and generates energy for ejecting liquid through the injection opening;

[0009] A second energy generating element is disposed at a position corresponding to the independent channel of the channel forming part, and generates energy for transferring liquid through the independent channel;

[0010] A temperature detection unit, configured to detect temperature, is located at a position corresponding to either the first energy generating element or the second energy generating element; and

[0011] The control unit is configured to control the drive of the second energy generating element based on the detection results of the temperature detection unit.

[0012] According to this disclosure, a liquid injection device capable of suppressing excessive liquid circulation can be provided.

[0013] The features of this disclosure will become apparent from the following description of embodiments with reference to the accompanying drawings. The following description of the embodiments is by way of example. Attached Figure Description

[0014] Figure 1A and Figure 1B This is a schematic perspective view showing the overall configuration of the liquid injection device according to the first embodiment;

[0015] Figure 2 This is a control block diagram showing the control system of the liquid injection device according to the first embodiment;

[0016] Figures 3A to 3D This is a schematic diagram used to explain the liquid injection head according to the first embodiment;

[0017] Figures 4A to 4C This is a schematic diagram used to explain the relevant parts of the liquid injection head according to the first embodiment;

[0018] Figure 5 This is a flowchart of the cyclic quantity control according to the first embodiment;

[0019] Figures 6A to 6F This is a diagram used to explain the driving timing according to the first embodiment;

[0020] Figure 7 This is a schematic diagram used to explain the relevant parts of the liquid injection head according to the second embodiment;

[0021] Figure 8 This is a flowchart of the cyclic quantity control according to the second embodiment;

[0022] Figure 9A and Figure 9B This is a schematic diagram used to explain the driving timing according to the second embodiment;

[0023] Figures 10A to 10C This is a schematic diagram used to explain the relevant parts of the liquid injection head according to the third embodiment;

[0024] Figure 11 This is a schematic diagram used to explain the relevant parts of the liquid injection head according to the fourth embodiment;

[0025] Figure 12A and Figure 12B This is a schematic diagram used to explain the relevant parts of the liquid injection head according to the fifth embodiment;

[0026] Figure 13 This is a schematic diagram used to explain relevant parts of the liquid injection head according to the sixth embodiment; and

[0027] Figure 14 This is a flowchart of the cyclic quantity control according to the seventh embodiment. Detailed Implementation

[0028] In the following description, various exemplary embodiments (examples), features, and aspects of the present disclosure will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, etc., of the components described in the various embodiments may be suitably varied depending on the configuration of the device to which the present disclosure is applied, various conditions, etc. Therefore, the dimensions, materials, shapes, relative arrangements, etc., of the components described in the various embodiments are not intended to limit the scope of the present disclosure to the following embodiments.

[0029] This disclosure relates to a recording element unit disposed in a liquid ejection head for performing recording, etc., by ejecting liquid onto a recording medium. This disclosure is applicable, for example, to a recording element unit disposed in the inkjet head of an inkjet printer, which performs recording by using heat to form bubbles in a liquid such as ink. However, the application of the recording element unit according to this disclosure is not limited thereto, and the recording element unit can also be used as a recording element unit in various liquid ejection heads that use heat to eject liquid.

[0030] The liquid ejector head and liquid ejection device provided with the liquid ejector head according to some embodiments of the present disclosure will now be explained with reference to the accompanying drawings. In the following description of the embodiments, specific configurations of the liquid ejector head for ink ejection will be explained, but the present disclosure is not limited thereto. The liquid ejector head according to the present disclosure can be applied to printers, copiers, fax machines with communication systems, word processors with a printer section, and industrial recording devices combined with various processing devices. For example, the liquid ejector head can also be used in applications such as biochip manufacturing and electronic circuit printing.

[0031] First Embodiment

[0032] The liquid jetting apparatus 50 according to the first embodiment of the present disclosure will now be explained. The liquid jetting apparatus 50 is an inkjet recording apparatus using an inkjet recording method, and includes a liquid jetting head 1 capable of jetting ink as a liquid.

[0033] Liquid injection device

[0034] The overall configuration of the liquid injection device 50 according to the first embodiment will now be explained. Figure 1A and Figure 1B This is a perspective view showing the configuration of the recording section of the liquid jetting device 50. The liquid jetting device 50 is a serial liquid jetting device in which an image is recorded by simultaneously jetting liquid onto the recording medium P while scanning the liquid jetting head 1 in a direction intersecting the transport direction of the recording medium P.

[0035] This disclosure is not limited to serial liquid jetting apparatuses, but also applies to page-width liquid jetting apparatuses that perform image recording by jetting liquid using a line head (page-width head) that is longer in the page-width direction of the recording medium.

[0036] The liquid ejector head 1 can eject four types of ink: black (K), cyan (C), magenta (M), and yellow (Y), and can use these inks to record panchromatic images. The liquid ejector head is not limited to these four types of ink. This disclosure also applies to liquid ejector heads used for ejecting other types of ink. In other words, there are no limitations on the type and quantity of ink ejected from the liquid ejector head.

[0037] In the following description, the scanning direction (movement direction) of the liquid jet head 1 will be referred to as the X direction; the direction in which the recording unit transports the recording medium P will be referred to as the Y direction; and the vertical direction will be referred to as the Z direction. Each of the X, Y, and Z directions intersects (or is orthogonal to) the other directions. Sometimes, the direction in which the liquid jet head 1 scans (moves) will be referred to as the main scanning direction, and the direction in which the recording medium P is transported will be referred to as the secondary scanning direction.

[0038] In the serial liquid jetting device 50, the liquid jetting head 1 is mounted on a carrier 60. The carrier 60 moves back and forth along the guide shaft 51 in the main scanning direction (X direction). The recording medium P is conveyed by transport rollers 55, 56, 57, and 58 included in the transport section (conveyor) in the secondary scanning direction (Y direction), which intersects (orthogonally in this example) the main scanning direction.

[0039] Figure 1A This is a perspective view showing an exemplary configuration in which the main ink tank 2, as a liquid reservoir, is disposed on the body of the liquid ejection device 50 (outside the liquid ejection head 1), and the auxiliary ink tank 54 is disposed on the liquid ejection head 1. The liquid (ink) stored in the ink tank 2 is supplied to the auxiliary ink tank 54 inside the liquid ejection head 1 by means of the driving force of an external pump 21, for example, through an ink supply tube (liquid passage) 59. In other words, in Figure 1A In the example shown, a liquid storage unit for storing ink is provided in each of the body of the liquid jetting device 50 and the liquid jetting head 1.

[0040] Figure 1B This is a perspective view showing an exemplary configuration in which the main ink tank 2 is not present, but the ink tank 54 is positioned directly above the liquid ejector head 1. The liquid ejector head 1 may be integrated with the ink tank 54 and is configured to be removable from the carrier 60. Alternatively, the liquid ejector head 1 may be integrated with the carrier 60, wherein only the ink tank 54 is configured to be removable. In the following description, Figure 1A The configuration shown will be used as a representative example.

[0041] The liquid jet head 1 includes individual jetting units, which will be described later. Each individual jetting unit (its specific configuration will be described later) is a recording element unit, including a jet opening through which liquid is ejected, a pressure chamber communicating with the jet opening, and an independent channel communicating with the pressure chamber. Each individual jetting unit includes a first energy generating element (jet energy generating element) disposed at a position corresponding to the pressure chamber and generating energy for ejecting liquid from the jet opening; and a second energy generating element (fluid energy generating element) disposed at a position corresponding to the independent channel. The liquid jet head 1 has multiple individual jetting units and a supply channel for supplying liquid to the independent channels included in each individual jetting unit.

[0042] When the liquid ejection head 1 is in use, ink ejection may become unstable due to factors such as the evaporation of volatile components (e.g., moisture) in the ejection opening and the accumulation of solids near the ejection opening. Various designs have been proposed to prevent this instability. For example, the liquid ejection device 50 may have a cap member (not shown) positioned along the X-direction, separate from the transport path of the recording medium P, which covers the ejection opening surface of the liquid ejection head 1. The cap member serves to prevent the ejection opening from drying out and protect the ejection opening by covering it when no recording operation is being performed.

[0043] An ink suction mechanism (not shown) may also be provided for the liquid jetting device 50. When such an ink suction mechanism is provided, for example, a cap member is used in the operation of suctioning ink from the jet opening. By performing this ink suction operation, the ink near the jet opening can be updated and the image quality of the obtained image can be maintained.

[0044] In addition, thickened ink can be removed by a so-called pre-spray (pre-spray) when no recording operation is being performed. This pre-spray can also be performed during recording by spraying an imperceptible amount of ink onto the recording medium at a location that has no significant impact on image quality (paper pre-spray / page pre-spray). While these methods greatly contribute to improved image quality, there is a need to minimize waste ink as much as possible because some ink is removed when the spray nozzles are refreshed.

[0045] Regarding this requirement, by providing a second energy-generating element (fluid energy-generating element) in an independent channel and circulating the ink through the channel, it is possible to suppress both waste ink volume and ink drying at the jet opening and ink thickening near the jet opening. More specifically, the number of pre-jet and suction recovery operations can be minimized. Furthermore, by reducing the number of pre-jet operations, throughput and production can also be increased.

[0046] It is not necessary to provide a second energy generating element (fluid energy generating element) for each individual injection unit included in the liquid jet head. Compared with a configuration without a second energy generating element, the above-mentioned advantageous effects can be achieved by providing a second energy generating element for only a portion of the individual injection units.

[0047] The liquid jet head 1 may also have a configuration in which a second energy generating element is provided in a portion corresponding to each of the four inks, or in a configuration in which a second energy generating element is provided in a portion corresponding to only one ink. That is, the liquid jet head may be configured to circulate at least one ink, but not all four inks.

[0048] Figure 2 This is a block diagram showing the control system of the liquid injection device 50. The CPU 800 is a control unit used to control the operation of various parts of the liquid injection device 50 based on a program (such as a processing flow) stored in the ROM 301. When the CPU 800 executes processing, the RAM 302 is used as a working area, etc. The CPU 800 receives image data from the host device 400 outside the liquid injection device 50 and controls the driving of the injection element set to the liquid injection head 1 by controlling the head driver 1A based on the image data.

[0049] The CPU 800 also controls the drivers of various actuators disposed in the liquid jetting device 50. For example, the CPU 800 controls the motor driver 303A of the carrier motor 303 for moving the carrier 60, the motor driver 304A of the transport motor 304 for transporting the recording medium P, and the pump driver 21A of the external pump 21. Although Figure 2 The configuration for receiving image data from the host device 400 is shown, but processing can also be performed on the liquid jetting device 50 without using any data from the host device 400.

[0050] Liquid injection head

[0051] An exemplary configuration of the liquid jet head 1 will now be explained. Figures 3A to 3D This is a schematic diagram used to explain the liquid injection head 1 according to the first embodiment. Figure 3A This is an exploded perspective view of liquid injection head 1.

[0052] The liquid ejector head 1 includes four sub-ink tanks 54 for temporarily storing ink in the ejector head, and a liquid ejector chip 3 for ejecting ink supplied from the sub-ink tanks 54 onto the recording medium P.

[0053] The liquid ejector head 1 also includes a first support member 4, a second support member 7, and an electrical wiring member (electrical wiring tape) 5. The liquid ejector plate 3 is connected to one surface of the first support member 4, and the ink reservoir 54 is connected to the other surface of the first support member. The first support member 4 has a channel passing through it from the one surface to the other surface, and while supporting the liquid ejector plate 3, the first support member 4 transfers ink supplied from the ink reservoir 54 to the liquid ejector plate 3.

[0054] The second support member 7 is connected to the surface of the first support member 4 where the liquid jet 3 is attached. The second support member 7 has an opening through which the liquid jet 3 can pass, and the second support member 7 is connected to the first support member 4 when the liquid jet 3 is positioned within the opening. The second support member 7 also serves to support the electrical wiring member 5.

[0055] The electrical wiring component 5 is electrically connected to the liquid jetting plate 3 and sends the jetting signal for ink jetting received from the main body of the liquid jetting device 50 to the liquid jetting plate 3.

[0056] According to the first embodiment, the liquid ejection head 1 is fixed to and supported by the carrier 60 of the liquid ejection device 50 via an alignment unit and electrical contacts (not shown) provided on the carrier 60. The liquid ejection head 1 performs recording on the recording medium P by moving together with the carrier 60 along the main scanning direction (X direction) while ejecting ink.

[0057] An ink supply tube 59 is connected to an external pump 21, which is connected to a main ink tank 2 serving as an ink source. A liquid connector (not shown) is provided at the end of the ink supply tube 59. When the liquid ejector head 1 is mounted on the liquid ejector device 50, the liquid connector at the end of the ink supply tube 59 is liquid-tightly connected to a liquid connector insertion port, which is a liquid inlet located in the head housing of the liquid ejector head 1. In this way, an ink supply channel is formed extending from the ink tank 2 via the external pump 21 to the liquid ejector head 1. In the first embodiment, since four types of ink are used, a total of four sets of ink tanks 2, external pumps 21, ink supply tubes 59, and auxiliary ink tanks 54 are provided in a manner corresponding to the corresponding inks. The liquid ejector device 50 is also provided with four independent ink supply channels corresponding to the corresponding inks.

[0058] As described above, the liquid ejection device 50 is provided with an ink supply system for supplying ink from the ink tank 2 outside the liquid ejection head 1. Note that the liquid ejection device 50 does not have an ink recovery system for recovering ink from the liquid ejection head 1 back to the ink tank 2. Therefore, although a liquid connector insertion port is provided for connecting the ink supply tube 59 to the ink tank 2, the liquid ejection head 1 does not have a connector insertion port for connecting the tube for recovering ink from the liquid ejection head 1 back to the ink tank 2. The liquid connector insertion port is provided corresponding to the respective ink.

[0059] Figure 3B , Figure 3C and Figure 3D This is a schematic diagram illustrating an exemplary configuration of a liquid jetting plate 3 included in a liquid jetting head 1. Figure 3B An exemplary configuration is shown, which includes one jet sheet corresponding to four ink colors. Figure 3C An exemplary configuration is shown, which includes a jetting plate corresponding to two ink colors. Figure 3D An exemplary configuration corresponding to one ink color is shown, comprising one spray plate. Each liquid spray plate is provided with a spray opening 11 and pads for electrical implementation. Figure 3A The chip configuration shown has Figure 3B The configuration shown.

[0060] Figure 3B An example is shown where a liquid jetting plate 3 is provided corresponding to four ink colors, so the liquid jetting head 1 has one liquid jetting plate 3. These four colors are, for example, black, cyan, magenta, and yellow. The liquid jetting plate 3 is provided with rows of jet openings, each row including a plurality of jet openings 11 arranged at equal intervals along the Y direction, where each row of jet openings corresponds to a corresponding color. In this example, two rows of jet openings are provided corresponding to each color, offset from each other in the X direction. Alternatively, one row of jet openings could be provided for each color instead of two. Two rows of jet openings could also be provided only for black, resulting in a total of five rows of jet openings for the four colors.

[0061] Figure 3C An example is shown in which one liquid jetting plate 3 is set for each of the two ink colors, so the liquid jetting head 1 has two liquid jetting plates 3. As a possible implementation of the two jetting plates on the liquid jetting head 1, two jetting plates can be implemented on one liquid jetting head 1, or two heads can be prepared, each with one jetting plate.

[0062] Figure 3D An example is shown where one liquid jetting blade 3 is set corresponding to one ink color, thus the liquid jetting head 1 has four liquid jetting blades 3. In this example, four jetting blades can be implemented on one liquid jetting head 1, or they can be arranged in a specific order. Figure 3C The example in the image is prepared in the same way as the four heads on which each have a spray plate applied.

[0063] Furthermore, in configurations using multiple jetting blades, such as in Figure 3C and Figure 3DIn the example shown, all the spray sheets do not need to have the same length. As for the number of colors corresponding to a single spray sheet, various other combinations are still possible, and this applies even when the total number of colors exceeds four.

[0064] Liquid jetting sheet

[0065] The configuration of the liquid jet plate 3 will now be explained in more detail. Figures 4A to 4C This is a schematic diagram for explaining the channel configuration of the liquid jet sheet 3 according to the first embodiment. Figure 4A This is a schematic diagram used to explain the configuration near the injection opening 11 on the liquid injection plate 3, and it is also a schematic diagram showing the positional relationship between the main components when viewed along the Z direction. The Z direction is approximately parallel to the direction in which the liquid is ejected from the injection opening 11. Figure 4B It is along Figure 4A The cross-sectional view taken from AA in the image. Figure 4C It is shown that... Figure 4A An enlarged schematic diagram of the portion corresponding to the independent channel in the diagram.

[0066] The liquid jetting sheet 3 includes a substrate 18 having a jetting opening 11, and an orifice plate 19 connected to the substrate 18 and having channels therein. This orifice plate is a channel-forming portion having channels through which ink flows. Figure 4A In order to indicate the positional relationship of the main components, the first energy generating element 14 and the second energy generating element 24 are given a relative position. Figure 4B The corresponding shaded lines are shown in the same way, and the ejection opening 11 is indicated by solid lines. Ink supplied from ink tank 54 passes through channels formed in substrate 18 and is ejected through ejection opening 11.

[0067] The liquid jetting plate 3 includes a jetting opening 11, a pressure chamber 13 communicating with the jetting opening 11, and an independent channel 23 communicating with the pressure chamber 13. An orifice plate 19 is a plate member having a plurality of jetting openings 11 formed therein and is connected to a substrate 18. The pressure chamber 13 and the independent channel 23 are arranged corresponding to each jetting opening 11, and the orifice plate 19 and the substrate 18 form part of its inner wall. The independent channel 23 communicates with the pressure chamber 13 on both sides in the X direction. In other words, the pressure chamber 13 can be considered as part of the independent channel 23. Figure 4C As shown, when viewed along the Z-direction, the independent channel 23 according to the first embodiment has a U-shaped shape. Hereinafter, this shape of the channel will be referred to as the U-shaped shape.

[0068] When viewed along the Z-direction, the first energy generating element 14 is disposed on the substrate 18 at a position overlapping with the jet opening 11 and the pressure chamber 13. The first energy generating element 14 is an element for generating energy to cause the jet opening 11 to eject ink, and a thermoelectric transducer may be used, for example.

[0069] When viewed along the Z-direction, the second energy generating element 24 is also disposed on the substrate 18 at a position corresponding to the independent channel 23 (specifically, at a position different from the first energy generating element 14 and overlapping with the independent channel 23). The second energy generating element 24 is an element that generates energy for circulating ink through the independent channel 23 and may have the same configuration as the first energy generating element 14. In the first embodiment, the first energy generating element 14 and the second energy generating element 24 are disposed adjacent to each other in the Y-direction, with a partition wall between them. That is, the first energy generating element 14 is disposed corresponding to one linear portion of the U-shape of the independent channel 23, while the second energy generating element 24 is disposed corresponding to the other linear portion.

[0070] The substrate 18 is also provided with a common channel 15 communicating with multiple independent channels 23, and a supply tank 12 communicating with the common channel 15, serving as a channel through which ink flows. Ink is supplied from the supply tank 12 formed in the substrate 18 to the independent channels 23 through the common channel 15. Energy generated by the second energy generating element 24 causes the ink to circulate along the independent channels 23 in a direction from the second energy generating element 24 to the first energy generating element 14. Figures 4A to 4C The arrows indicate the circulating flow 27, which is the ink flow circulating through the independent channel 23. That is, the independent channel 23 is a circulation channel that allows ink to circulate, and the second energy generating element 24 generates energy to allow the ink to circulate through the independent channel 23.

[0071] In the first embodiment, two rows of ejection openings are provided, each row including a plurality of ejection openings 11 arranged along the Y direction. A supply groove 12 is provided between the two rows of ejection openings in the X direction. The supply groove 12 is a groove that is longer in the Y direction and forms a channel for supplying ink supplied from the ink tank 54 through the first support member 4 to the independent channel 23.

[0072] The substrate 18 also has a common liquid chamber 29 communicating with the supply tank 12. Ink supplied from the ink tank 54 flows into the common liquid chamber 29. In other words, the ink supplied from the ink tank 54 flows through the common liquid chamber 29 and the supply tank 12 to reach the independent channel 23.

[0073] Now refer to Figure 4CExplain the circulation system. At each end of the independent channel 23, the end from which ink flows in when the circulating flow 27 is generated will be referred to as inlet 25, and the other end from which ink flows out will be referred to as outlet 26. Pressure chamber 13 and the first energy generating element 14 are located near outlet 26, while the second energy generating element 24 is located near inlet 25. In the U-shaped independent channel 23, outlet 26 and inlet 25 are adjacent to each other in the Y direction. In the following description of ink (liquid) flow and circulation volume control, pressure chamber 13 will be considered as part of independent channel 23.

[0074] At the spray opening 11, the water content (volatile components) in the ink evaporates, increasing the ink viscosity and making it thickened. By generating a circulating flow 27 through the second energy generating element 24, the thickened ink flows out through the outlet 26. In this way, by displacing the thickened ink at the spray opening 11, the problem of ink thickening can be solved.

[0075] As the ink circulates, it exits the independent channel 23 through outlet 26 and simultaneously enters the independent channel 23 through inlet 25. Therefore, when outlet 26 and inlet 25 are positioned close to each other, for example, as in a U-shaped independent channel 23, thickened ink with water content evaporating at the jet opening may re-enter the independent channel 23. Thus, excessive circulation leads to a new challenge: continued ink thickening occurs in each independent channel 23. To suppress the progression of ink thickening in each independent channel 23 (ink thickening accompanied by microcirculation), it is important to control the amount of ink to be circulated, thereby preventing any ink circulation beyond what is necessary.

[0076] In the first embodiment, a thermoelectric transducer is used as the first energy generating element 14 and the second energy generating element 24. Other types of elements (such as piezoelectric elements) may also be used as the second energy generating element 24.

[0077] The substrate 18 includes a temperature sensing element 34, which serves as a temperature sensing section (temperature detection part), for detecting the temperature of at least one of the independent channel 23 and the pressure chamber 13. In the first embodiment, the temperature sensing element 34 is disposed at a position corresponding to the pressure chamber 13, specifically at a position that overlaps with the injection opening 11 and the first energy generating element 14 when viewed along the Z direction. Figure 4B As shown, the temperature sensing element 34 is positioned directly below the first energy generating element 14, that is, on the side that is further away from the independent channel 23 and the injection opening 11 than the first energy generating element 14.

[0078] For the first energy generating element 14, the detected temperature changes over time: it rises due to the application of a driving voltage pulse, reaches a peak temperature, and then falls, with a characteristic point of sudden temperature drop during the falling process. This characteristic point is caused by a significant change in thermal conductivity due to the replacement of gas with liquid at the location corresponding to the first energy generating element 14 during the bursting of the liquid bubble, which is formed by heating by the first energy generating element 14.

[0079] As the ink in each individual channel 23 becomes more viscous due to the thickening effect of the ink, the viscous resistance also increases, the time for ink bubble rupture is prolonged, and the timing of feature point appearance is correspondingly delayed. Utilizing this time difference in ink bubble rupture at different ink viscosities, the viscosity in the individual channels 23 can be detected by causing the first energy generating element 14 to perform thickening detection drive.

[0080] Furthermore, if a drive pulse used for normal ink ejection is applied to the first energy generating element 14 in this thickening detection drive to detect viscosity, ink is ejected and falls onto the paper surface, etc., thereby affecting the output image. Therefore, unlike the normal drive pulse used for ordinary ink ejection, it is preferable to apply a drive pulse whose energy is low enough to form bubbles but not enough to eject ink, or energy that forms bubbles and ejects ink but is low enough not to cause ink to fall onto the print. In this way, viscosity information in the independent channel 23 can be detected without affecting the print while suppressing ink consumption.

[0081] In the first embodiment, the liquid jetting device 50 is able to control the amount of ink circulating based on viscosity information (temperature information) in the independent channel 23. Reference will now be made to... Figure 5 Explain the cyclic variable control. Figure 5 This is a flowchart of the cyclic quantity control according to the first embodiment.

[0082] First, in step (hereinafter referred to as "S") 101, the timing of viscosity detection is pre-set to a characteristic point generated by normal viscosity within the channel by referring to the thickening detection driving conditions of the pulse to be applied to the first energy generating element 14. In other words, the detection timing is set at a point where the temperature of the independent channel 23 suddenly drops due to the driving of the first energy generating element 14, when the ink viscosity in the independent channel 23 is normal. However, the detection timing is not limited to this and can be appropriately set within the range of temperature drop in the independent channel 23.

[0083] In S102, since a temperature difference occurs at the feature point, a temperature threshold T0 corresponding to the detection timing is preset. The threshold T0 can be set by making a prediction in advance (e.g., before leaving the factory) or by creating a normal viscosity state within the channel during operation after leaving the factory (e.g., immediately after suction recovery).

[0084] In S103, the cycle drive is then performed by driving the second energy generating element 24. The second energy generating element 24 is driven under the control of the CPU 800, which is a control unit. As a result of driving the second energy generating element 24, a circulating flow 27 is formed in the independent channel 23, and the ink is circulated.

[0085] In S104, thickening detection drive is then performed by driving the first energy generating element 14. At this time, the amount of energy generated by the first energy generating element 14 is less than the amount of energy generated in the jet drive (jet operation) for ejecting ink from the jet opening 11. The first energy generating element 14 is driven under the control of the CPU 800, which is a control unit, in the same manner as the second energy generating element 24.

[0086] In S105, the temperature sensing element 34 is then driven, and the temperature sensing element 34 detects temperature T1. In S106, the CPU 800 then acquires the temperature T1 at the time of detection performed by the temperature sensing element 34.

[0087] In S107, the CPU 800 then compares the temperature T1 obtained in S106 with the threshold T0 set in S102, and determines whether the viscosity within the channel is normal based on the comparison result. Specifically, in S107, it determines whether T1 ≤ T0. If T1 ≤ T0, that is, if the determination result in S107 is yes, the processing timing proceeds to S108 to determine that the viscosity within the channel is normal, and the loop control ends. Conversely, if T1 > T0, that is, if the determination result in S107 is no, the processing timing proceeds to S109, and it is determined that the viscosity within the channel is high.

[0088] If the viscosity within the channel is determined to be high in S109, it is considered that the circulation amount for thickening ink in independent channel 23 is still insufficient, and the second energy generating element 24 is driven in S110 to perform additional circulation drive. After performing the additional circulation drive, the processing sequence returns to S104, and the thickening detection drive is performed again. When the ink is circulated using the second energy generating element 24, a small amount of ink is circulated by driving the second energy generating element 24 once, and the circulation amount increases proportionally to the number of times the second energy generating element 24 is driven. Therefore, it is preferable to return the processing sequence to S104 after performing a fixed number of additional drives.

[0089] In the first embodiment, in S107, the acquired temperature T1 is compared with a threshold T0 at the time of detection. This configuration is important from the perspective of judgment accuracy because it ensures a wider range for setting the threshold. Ensuring a wider range enhances robustness to nozzle size deviations and deviations in ink physical properties due to ink changes over time.

[0090] In the first embodiment, since independent channels 23 are provided corresponding to each ejection opening 11, and a first energy generating element 14, a second energy generating element 24, and a temperature sensing element 34 are provided, the circulation volume can be controlled on a unit of one ejection opening 11. The thickened ink state within the independent channel 23 varies depending on factors such as the usage frequency of the ejection opening 11 (the frequency of ink ejection). However, using the configuration of the first embodiment, the circulation drive can be performed in a manner suitable for each ejection opening 11, and the ink thickening progress caused by excessive ink circulation volume can be suppressed for each independent channel 23.

[0091] In the first embodiment, when comparing the temperature at the time of detection with a threshold, the temperature information detected by the temperature detection element 34 is used directly; however, the invention is not limited to this configuration. Since a feature point where the temperature changes abruptly is used, the feature point can be enhanced, for example, by calculating the first or second derivative of the temperature change over time, and then the temperature of that feature point can be compared with the threshold T0.

[0092] Furthermore, in the first embodiment, the determination is made by comparing the temperature at the time of detection with a threshold. In contrast, the viscosity within the channel can also be determined by utilizing the fact that feature points appear at different times depending on whether the viscosity is normal or high. Specifically, the time of appearance of the feature points (e.g., a period of time from the start of the cycle drive) can also be detected, and the viscosity within the channel can be determined as normal or still high based on the time difference between this time and the time when the feature points appear at normal viscosity. In this case, if there is no time difference or the time difference is less than a predetermined threshold, the viscosity within the channel can be determined to be normal. If there is a time difference or the time difference is equal to or greater than the predetermined threshold, the viscosity within the channel can be determined to be high.

[0093] Alternatively, the viscosity within the channel can be determined to be normal or high by utilizing the transition from a state where high viscosity has been resolved (low viscosity) to a more viscous state (higher viscosity) as the cycle continues. Specifically, the time difference between the time when a feature point appears in the current thickening detection drive and the time when a feature point appears during the previous thickening detection drive can be used. In this case, if there is no time difference or the time difference is less than a predetermined threshold, it is determined that the ink thickening within the channel has been resolved and the viscosity within the channel has returned to normal. If there is any time difference or the time difference is equal to or greater than the predetermined threshold, ink thickening is currently being resolved, and therefore the viscosity within the channel remains high. In this way, even without directly using the detection results (temperature information), as long as the detection results of the temperature detection element 34 are used, it is possible to determine whether the viscosity within the channel is normal or high in any way.

[0094] Figures 6A to 6F This is a diagram used to explain the drive timing, including injection-driven and cycle-driven systems. Figures 6A to 6F In the diagram, the horizontal axis represents time. The vertical lines (solid lines) plotted on these axes represent the timing of the injection drive and the cycle drive, respectively. On the injection drive axis, the timing of the thickening detection drive is also plotted as a vertical line (dashed line). In other words, the timing for driving the first energy generating element 14 is plotted on the axis corresponding to the injection drive, while the timing for driving the second energy generating element 24 is plotted on the axis corresponding to the cycle drive.

[0095] Figure 6A and Figure 6B This is the driving timing diagram for the proportional aspect ratio. Figure 6C , Figure 6D , Figure 6E and Figure 6F It is a driving timing diagram according to the first embodiment.

[0096] Figure 6A The following is illustrated a drive timing sequence that corresponds to a cyclic drive (hereinafter referred to as later-in-time packed driving) that performs a specific number of cyclic operations at a specific frequency when the injection drive stops but just before the end of such a stop period. Figure 6B The following is a driving timing diagram that corresponds to a cyclic drive (hereinafter referred to as an intermittent drive) that performs cyclic operations at a specific frequency and at fixed time intervals when the injection drive stops.

[0097] In these comparative methods, because the timing and number of cycles need to be predetermined, the jetting history and the variation in circulation volume between nozzles must be considered to ensure sufficient circulation volume margin. If the circulation volume is set in this way, it may exceed the amount needed to address ink thickening. As a result, ink thickening due to excessive circulation volume, characteristic of micro-circulation, may continue to occur in individual channels.

[0098] In contrast, using the configuration according to the first embodiment, by executing the thickening detection driver, the execution timing and number of times of the loop driver can be determined based on the detection result or the determination result. The driving timing for executing the thickening detection driver and then executing the loop driver based on the result of the thickening detection driver will now be explained.

[0099] Figure 6C An example of executing a thickening detection drive within the post-fill drive timing is shown. In this example, the thickening detection drive is executed after the loop drive has been executed a predetermined number of times, and the determination result of the thickening detection drive is fed back to the loop drive. If the determination indicates that ink thickening has been resolved, the loop drive can be controlled to terminate, thus avoiding the execution of unnecessary loop drives. Conversely, if the determination indicates that ink thickening has not been sufficiently resolved, additional loop drives can be executed to increase the loop rate and resolve ink thickening within the channel. Figure 6C An example is shown where, in the first thickening detection drive, it is determined that ink thickening has not been sufficiently resolved, so additional loop drives are executed multiple times, and in the second thickening detection drive, it is determined that ink thickening has been resolved. Note that the parameters of the loop control can be adjusted by reducing the number of times the second energy generating element 24 is driven.

[0100] Figure 6D An example of performing a thickening detection drive in an intermittent drive sequence is shown. In this example, the thickening detection drive is performed after the intermittently repeated loop drive, and the determination result is fed back to the loop drive. Even in this case, the number of subsequent loop drives to be executed can be determined based on the determination result. Examples of parameters used to control the loop amount include: the number of drives of the second energy generating element 24, the time interval for executing the loop drive, and whether subsequent loop drives are executed in the intermittent loop drive. Figure 6D An example of the driving timing is shown below, which intermittently executes a four-cycle driving, but after the first thickening detection driving, the number of executions is reduced to two based on the decision result.

[0101] Figure 6EAn example is shown where thickening detection is performed before the loop drive in a post-fill drive timing sequence. With this timing selected, loop volume control can be performed simultaneously with detecting ink thickening being addressed by maintaining ink thickening detection before the loop and performing the loop drive based on the ink thickening detection results.

[0102] Figure 6F An example of performing a thickening detection drive before the first cycle drive in an intermittent drive timing is shown. Even in this timing case, the ink thickening status in the channel can be detected, and the cycle volume can be controlled based on the ink thickening status.

[0103] As described above, using the configuration according to the first embodiment, based on the detection result of the temperature detection element 34, ink thickening in the channel can be detected by determining whether a temperature drop occurs at a detection timing corresponding to a characteristic point of temperature change at normal viscosity during the temperature decrease process. By feeding the detection result back to the circulation drive, the drive of the second energy generating element 24 is controlled, thereby executing the circulation drive in a manner that prevents the circulation amount from becoming excessive. In this way, the circulation amount in each jet opening 11 (nozzle) can be suppressed, and the thickening progress that occurs in the individual channel 23 accompanied by excessive circulation can be suppressed. Because the time during which the thickening effect is suppressed can be maximized, the maintenance time required for suction recovery operations and the resulting waste ink amount can be reduced.

[0104] Furthermore, in the configuration according to the first embodiment, since the temperature sensing element 34 is located directly below the first energy generating element 14, it can also be used to perform jet detection for detecting whether ink is being properly jetted. This operation utilizes the fact that the timing of the characteristic point accompanying bubble rupture differs between when jetting is normal and when there is no jetting due to poor jetting. Therefore, the same temperature sensing element can be used to perform this jet detection and cycle volume control.

[0105] Although the temperature sensing element 34 is positioned directly below the first energy generating element 14 in the first embodiment, the present invention is not limited to this configuration. Since the purpose of installing the temperature sensing element 34 is to detect temperature changes near the first energy generating element 14 when it is driven for thickening detection, the temperature sensing element 34 can be positioned at any location corresponding to the first energy generating element 14, such as directly above or near the first energy generating element 14. Furthermore, an element that combines the energy generation function of the first energy generating element 14 and the temperature sensing function of the temperature sensing element 34 can be provided, without a separate temperature sensing element 34.

[0106] Second Embodiment

[0107] The second embodiment of this disclosure will now be explained. The second embodiment differs from the first embodiment in the placement of the temperature sensing element 34. In the following second embodiment, only elements different from those in the first embodiment will be explained. In the configuration according to the second embodiment, elements identical to those in the first embodiment will be given the same reference numerals, and their descriptions will be omitted.

[0108] Figure 7 This is a schematic diagram used to explain the configuration near the injection opening 11 on the liquid injection plate 3 according to the second embodiment, and it is along... Figure 4A The cross-sectional view taken from line AA in the diagram. In the second embodiment, the plan view of the liquid jet plate 3 when viewed along the Z direction and the enlarged schematic diagram of the portion corresponding to the independent channel are the same as those according to the first embodiment. Figure 4A and Figure 4C The same as in.

[0109] In the first embodiment, a thermoelectric transducer is used as the first energy generating element 14 and the second energy generating element 24. Other types of elements (such as piezoelectric elements) may also be used as the first energy generating element 14.

[0110] In the second embodiment, when viewed along the Z-direction, the temperature sensing element 34 is positioned at a location overlapping the second energy generating element 24. For example... Figure 7 As shown, the temperature sensing element 34 is positioned directly below the second energy generating element 24, that is, on a side further away from the independent channel 23 than the second energy generating element 24. Note that the temperature sensing element 34 does not need to be positioned directly below the second energy generating element 24, but can be positioned at any location corresponding to the second energy generating element 24.

[0111] Figure 8 This is a flowchart illustrating the loop quantity control according to the second embodiment. Because the loop quantity control according to the second embodiment has many similarities with the loop quantity control according to the first embodiment, only the differences relative to the first embodiment will be described below.

[0112] First, in S101, by referring to the thickening detection driving conditions of the pulse to be applied to the second energy generating element 24, the timing of viscosity detection is preset to a characteristic point generated when the viscosity in the channel is normal. In other words, this detection timing is set at the moment when the temperature of the independent channel 23 suddenly drops due to the driving of the second energy generating element 24, provided that the ink viscosity in the independent channel 23 is normal. However, the detection timing is not limited to this and can be appropriately set within the range of temperature drop in the independent channel 23.

[0113] like Figure 8As shown, in the second embodiment, the thickening detection drive executed in S104 of the first embodiment is omitted. This is because when the loop drive is executed in S103, the second energy generating element 24 is driven and the thickening detection drive is also executed. Therefore, after the loop drive and the thickening detection drive are executed in S103, the processing timing proceeds to S105, in which the temperature is output from the temperature detection element 34.

[0114] Furthermore, in the second embodiment, the timing of executing the additional loop drive in S110 after determining that the viscosity in the channel is high in S109 is omitted. This is because the loop drive is executed simultaneously with the thickening detection drive in S103. Therefore, after determining that the viscosity in the channel is high in S109, the processing timing returns to S103, and the loop drive and the thickening detection drive are executed synchronously.

[0115] Figure 9A and Figure 9B This is a schematic diagram used to explain the drive timing including injection drive and cycle drive according to the second embodiment. Figure 9A and Figure 9B In the diagram, the horizontal axis represents time, and the vertical lines (solid lines) drawn to these axes represent the timing of executing the injection drive and the cycle drive, respectively. In the second embodiment, the timing for executing the cycle drive is the same as the timing for executing the thickening detection drive.

[0116] Figure 9A An example of executing a thickening detection drive within a post-fill drive timing sequence is shown. In this example, a loop drive is executed just before the injection drive. In a second embodiment, the thickening detection drive and the loop drive are executed synchronously. The loop size can then be adjusted by determining the number of times subsequent loop drives and the thickening detection drive are executed synchronously based on the determination result of the thickening detection drive.

[0117] Figure 9B An example of performing thickening detection driving in an intermittent driving sequence is shown. In this example, a set of one or more loop drives is executed intermittently. Figure 9B An example is shown where the number of executions driven by the loop is gradually reduced: from four to two, and then from two to one.

[0118] In the configuration according to the second embodiment, the circulation amount can also be controlled by performing thickening detection driving in the same manner as in the first embodiment. Therefore, by detecting the ink thickening status in the channel based on the detection result of the temperature detection element 34 and feeding the detection result back to the circulation drive, the circulation drive can be performed by driving the second energy generating element 24 in a way that prevents the circulation amount from becoming excessive. As a result, since the circulation amount in each nozzle can be suppressed, the progress of ink thickening accompanied by excessive circulation amount in the individual channel 23 can be suppressed.

[0119] Furthermore, by positioning the temperature sensing element 34 at a position corresponding to the second energy generating element 24, the following advantages can be achieved. First, thickening detection drive and cycle drive can be performed simultaneously by driving the second energy generating element 24. Therefore, ink thickening can be detected during each cycle drive, thereby enabling fine cycle volume control. Furthermore, since ink is not ejected during cycle drive, viscosity detection can be performed by applying the drive pulse used in normal cycle drive, and the detection sensitivity is also improved.

[0120] Third Embodiment

[0121] The third embodiment of this disclosure will now be explained. The third embodiment differs from the first embodiment in the shape of the independent channel 23. In the following third embodiment, only elements different from those in the first embodiment will be explained. In the configuration according to the third embodiment, elements identical to those in the first embodiment will be given the same reference numerals, and their descriptions will be omitted.

[0122] Figures 10A to 10C This is a schematic diagram for explaining the channel configuration of the liquid jet sheet 3 according to the third embodiment. Figure 10A This is a schematic diagram for explaining the configuration near the injection opening 11 on the liquid injection plate 3, and a schematic diagram showing the positional relationship between the main components when viewed along the Z direction of the liquid injection plate 3. Figure 10A Only one row of multiple injection openings 11 arranged along the Y direction is shown. Figure 10B It is along Figure 10A The cross-sectional view taken from BB in the image.

[0123] Figure 10C It is shown that... Figure 10A An enlarged schematic diagram of the portion corresponding to the independent channels in the diagram. Figure 10A In order to indicate the positional relationship of the main components, the first energy generating element 14 and the second energy generating element 24 are given a relative position. Figure 10B The same corresponding shaded lines are used, and the injection opening 11 is represented by a solid line.

[0124] The independent channel 23 according to the third embodiment has a linear shape, such as Figure 10C As shown in the diagram. In the following text, this channel shape will be referred to as a straight-line shape. The straight-line independent channel 23 is arranged linearly, extending from the inlet 25 to the outlet 26 along the X direction. That is, the inlet 25 is located at one end of the independent channel 23 in the X direction, and the outlet 26 is located at the other end of the independent channel 23 in the X direction.

[0125] The first energy generating element 14 is positioned where it overlaps with the injection opening 11 and the independent channel 23 (pressure chamber 13) when viewed along the Z direction, and is closer to the outlet 26 in the X direction. The second energy generating element 24 is positioned where it overlaps with the independent channel 23 when viewed along the Z direction, and is positioned closer to the inlet 25 in the X direction. The temperature sensing element 34 is positioned where it overlaps with the first energy generating element 14 when viewed along the Z direction. By driving the second energy generating element 24, along the direction from the inlet 25 to the outlet 26 (in... Figure 10A (From center to right) A circulating flow 27 is generated in the independent channel 23, and the ink in the independent channel 23 is circulated.

[0126] The substrate 18 has a supply opening 22 on the upstream side of the independent channel 23 in the liquid circulation direction and a recovery opening 28 on the downstream side. Both the supply opening 22 and the recovery opening 28 are connected to the common channel 15. The substrate 18 further includes a common liquid chamber 29, which is connected to the supply opening 22 and the recovery opening 28, and ink supplied from the ink tank 54 is transferred to the common liquid chamber. Therefore, by driving the second energy generating element 24, the ink is transferred in such a way that it circulates sequentially through the common liquid chamber 29, the supply opening 22, the common channel 15, the independent channel 23, the common channel 15, the recovery opening 28, and the common liquid chamber 29. By enabling the ink to circulate in the above manner, the effect of solving the ink thickening problem can be achieved in the same way as in the first and second embodiments.

[0127] In a straight channel, since the outlet 26 and inlet 25 of the independent channel 23 are located separately from each other, the thickened ink evaporated at the spray opening is less likely to flow back into the independent channel 23 compared to a U-shaped channel. However, the configuration according to the third embodiment is no different in that the thickened ink evaporated at the spray opening remains in the common liquid chamber 29 connected to the independent channel 23. Therefore, when ink is excessively circulated, it is still necessary to address the ink thickening progress throughout the channel, including the independent channel 23 and the common liquid chamber 29. Therefore, in order to suppress the ink thickening progress accompanying circulation in the channel, it is preferable to control the circulation amount so as not to circulate any ink beyond the necessary amount.

[0128] In the configuration according to the third embodiment, the circulation amount can also be controlled by performing thickening detection drive using the same method as according to the first embodiment. Therefore, by detecting the ink thickening status in the channel based on the detection result of the temperature detection element 34 and feeding the detection result back to the circulation drive, the circulation drive can be performed by driving the second energy generating element 24 in a manner that prevents the circulation amount from becoming excessive. Thus, since the circulation amount in each nozzle can be suppressed, the progression of ink thickening accompanied by excessive circulation in the individual channel 23 can be suppressed.

[0129] The advantage of using a linear independent channel 23 is that the inlet 25 and outlet 26 for circulation are positioned separately from each other, making it less likely that thickened ink evaporated at the jet opening will re-enter the independent channel 23. Therefore, it is possible to focus solely on addressing ink thickening that accompanies over-circulation in the common liquid chamber 29.

[0130] Fourth embodiment

[0131] The fourth embodiment of this disclosure will now be explained. The fourth embodiment differs from the third embodiment in the placement of the temperature sensing element 34. In the following fourth embodiment, only elements different from those in the third embodiment will be explained. In the configuration according to the fourth embodiment, elements identical to those in the third embodiment will be given the same reference numerals, and their descriptions will be omitted.

[0132] Figure 11 This is a schematic diagram used to explain the configuration near the injection opening 11 in the liquid injection sheet 3 according to the fourth embodiment, and is along... Figure 10A A cross-sectional view taken from line BB in the diagram. A plan view of the liquid jet sheet 3 along the Z direction according to the fourth embodiment, and an enlarged schematic diagram of the portion corresponding to the independent channel, compared with the third embodiment. Figure 10A and Figure 10C The same as in.

[0133] In the fourth embodiment, the temperature sensing element 34 is positioned at a location that overlaps with the second energy generating element 24 when viewed along the Z-direction. Figure 11 As shown, the temperature sensing element 34 is positioned directly below the second energy generating element 24, that is, on a side further away from the independent channel 23 than the second energy generating element 24. Note that the temperature sensing element 34 does not need to be positioned directly below the second energy generating element 24, but can be positioned at any location corresponding to the second energy generating element 24.

[0134] In the configuration according to the fourth embodiment, the circulation amount can also be controlled by performing thickening detection drive using the same method as in the second embodiment. Therefore, by detecting the ink thickening status in the channel based on the detection result of the temperature detection element 34 and feeding the detection result back to the circulation drive, the circulation drive can be performed by driving the second energy generating element 24 in a manner that prevents the circulation amount from becoming excessive. Thus, since the circulation amount in each nozzle can be suppressed, the progression of ink thickening accompanied by excessive circulation in the individual channel 23 can be suppressed. Furthermore, since the individual channel 23 is linear, the same advantages as in the third embodiment can be achieved.

[0135] Fifth embodiment

[0136] The fifth embodiment of this disclosure will now be explained. The fifth embodiment differs from the first and third embodiments in the shape of the independent channel 23. In the following fifth embodiment, only elements different from those in the third embodiment will be explained. In the configuration according to the fifth embodiment, elements identical to those in the third embodiment will be given the same reference numerals, and their descriptions will be omitted.

[0137] Figure 12A and Figure 12B This is a schematic diagram for explaining the channel configuration of the liquid jet sheet 3 according to the fifth embodiment. Figure 12A This is a schematic diagram for explaining the configuration near the injection opening 11 of the liquid injection plate 3, and a schematic diagram showing the positional relationship between the main components when viewed along the Z direction of the liquid injection plate 3. Figure 12A Only one row of multiple injection openings 11 arranged along the Y direction is shown. Figure 12B It is along Figure 12A The cross-sectional view taken by CC in the image. Figure 12A In order to indicate the positional relationship of the main components, the first energy generating element 14 and the second energy generating element 24 are given a relative position. Figure 12B The same corresponding shaded lines are used, and the injection opening 11 is represented by a solid line.

[0138] According to the fifth embodiment, the independent channel 23 is a straight channel and branches into two branches along its path from the inlet 25 to the outlet 26. The independent channel 23 has an inlet 25 located at one end in the X direction and two outlets 26 located at the other end in the X direction. Two pressure chambers 13 (jet openings 11) are arranged in communication with one independent channel 23. The substrate 18 is provided with two first energy generating elements 14 and one second energy generating element 24 corresponding to one independent channel 23.

[0139] The first energy generating element 14 is disposed corresponding to each branch channel, and is positioned where it overlaps with the corresponding injection opening 11 and independent channel 23 (pressure chamber 13) when viewed along the Z direction, and is positioned closer to the outlet 26 in the X direction. The second energy generating element 24 is disposed in the portion not divided into two branches, and is positioned where it overlaps with the independent channel 23 when viewed along the Z direction, and is positioned closer to the inlet 25 in the X direction. By driving the second energy generating element 24, along the direction from the inlet 25 to the outlet 26 (in... Figure 12A (From center to right) A circulating flow 27 is generated in the independent channel 23, and the ink in the independent channel 23 is circulated.

[0140] In the fifth embodiment, a temperature sensing element 34 is provided for each independent channel 23. The temperature sensing element 34 is positioned at a location that overlaps with one of the first energy generating elements 14 when viewed along the Z direction. That is, a temperature sensing element 34 is not provided for each of the first energy generating elements 14.

[0141] In the configuration according to the fifth embodiment, the circulation amount can also be controlled by performing thickening detection driving using the same method as according to the first embodiment. Therefore, by detecting the ink thickening status in the channel based on the detection result of the temperature detection element 34 and feeding the detection result back to the circulation drive, the circulation drive can be performed by driving the second energy generating element 24 in a manner that prevents the circulation amount from becoming excessive. Thus, since the circulation amount in each nozzle can be suppressed, the progression of ink thickening accompanied by excessive circulation in the individual channel 23 can be suppressed.

[0142] The advantage of arranging two jet openings 11 and two first energy generating elements 14 corresponding to a single channel 23 is that the circulation rate can be controlled by detecting ink thickening based on the detection result of a temperature sensing element 34 corresponding to each of the two jet openings 11. Furthermore, the number of second energy generating elements 24 and temperature sensing elements 34 can be reduced relative to the number of first energy generating elements 14. However, in such a configuration, a temperature sensing element 34 may also be provided corresponding to each of the first energy generating elements 14.

[0143] Sixth Embodiment

[0144] The sixth embodiment of this disclosure will now be explained. The sixth embodiment differs from the fifth embodiment in the placement of the temperature sensing element 34. In the following sixth embodiment, only elements different from those in the fifth embodiment will be explained. In the configuration according to the sixth embodiment, elements identical to those in the fifth embodiment will be given the same reference numerals, and their descriptions will be omitted.

[0145] Figure 13 This is a schematic diagram used to explain the configuration near the injection opening 11 in the liquid injection sheet 3 according to the sixth embodiment, and is along... Figure 12A A cross-sectional view taken from line CC in the diagram. A plan view of the liquid jet sheet 3 along the Z direction according to the sixth embodiment and an enlarged schematic diagram of the portion corresponding to the independent channel, compared with the fifth embodiment. Figure 12A and Figure 12B The same as in.

[0146] In the sixth embodiment, the temperature sensing element 34 is positioned at a location that overlaps with the second energy generating element 24 when viewed along the Z-direction. Figure 13As shown, the temperature sensing element 34 is positioned directly below the second energy generating element 24, that is, on a side further away from the independent channel 23 than the second energy generating element 24. Note that the temperature sensing element 34 does not need to be positioned directly below the second energy generating element 24, but can be positioned at any location corresponding to the second energy generating element 24.

[0147] That is, the configuration according to the sixth embodiment differs from the configuration according to the fourth embodiment in that, in an independent channel 23, one second energy generating element 24 corresponds to (connected to) two first energy generating elements 14.

[0148] In the configuration according to the sixth embodiment, the circulation amount can also be controlled by performing thickening detection driving using the same method as according to the second embodiment. Therefore, by detecting the ink thickening status in the channel based on the detection result of the temperature detection element 34 and feeding the detection result back to the circulation drive, the circulation drive can be performed by driving the second energy generating element 24 in a manner that prevents the circulation amount from becoming excessive. Thus, since the circulation amount in each nozzle can be suppressed, the progression of ink thickening accompanied by excessive circulation in the individual channel 23 can be suppressed. Furthermore, since two injection openings 11 and two first energy generating elements 14 can be provided corresponding to one individual channel 23, the same advantageous effects as in the fifth embodiment can be achieved.

[0149] Seventh Embodiment

[0150] The seventh embodiment of this disclosure will now be explained. The seventh embodiment differs from the first and second embodiments in its method of controlling the cyclic quantity. In the following seventh embodiment, only elements different from those in the second embodiment will be explained. In the configuration according to the seventh embodiment, elements identical to those in the second embodiment will be given the same reference numerals, and their descriptions will be omitted.

[0151] The seventh embodiment differs from each of the above embodiments in that the circulation volume control is completed within the liquid injection head 1. In the seventh embodiment, the temperature detection element 34 is disposed at a position corresponding to the second energy generating element 24, and a control unit including a CPU, etc., is disposed in the liquid injection head 1. In other words, the liquid injection plate 3 has the same configuration as that according to any one of the second, fourth, and sixth embodiments described above.

[0152] In the seventh embodiment, the liquid jet head 1 can control the ink circulation volume based on viscosity information (temperature information) in the independent channel 23. Figure 14 This is a flowchart of the cyclic quantity control according to the seventh embodiment.

[0153] First, in S201, the second energy generating element 24 is driven to perform a cyclic drive. Since the temperature sensing element 34 is positioned corresponding to the second energy generating element 24, the thickening detection drive can be executed synchronously with the cyclic drive.

[0154] In S202, the temperature sensing element 34 is then driven and the temperature sensing element 34 detects the temperature T11. In S203, the control unit in the liquid injection head 1 then acquires the temperature T11 at the detection timing performed by the temperature sensing element 34.

[0155] In S204, the second energy generating element 24 is then driven to perform the cycle drive and thickening detection drive again. Next, in S205, the temperature sensing element 34 is driven and detects the temperature T12. In S206, the control unit in the liquid injection head 1 then acquires the temperature T12 at the detection timing performed by the temperature sensing element 34.

[0156] In S207, the control unit then acquires the temperature T11 obtained in S203 and the temperature T12 obtained in S206, and determines whether the relationship T12 ≤ T11 is satisfied. If T12 ≤ T11, that is, if the determination result in S207 is yes, the viscosity in the channel is determined to be normal and the cycle control is directly terminated. Conversely, if T12 > T11, that is, if the determination result in S207 is no, the viscosity in the channel is determined to be high, and the processing sequence is transferred to S208.

[0157] In S208, T11 is rewritten as T12, that is, the value of temperature T11 is changed to the value of temperature T12. Then, the processing timing is transferred to S204, which is a loop-driven process that is executed again.

[0158] In the seventh embodiment, as described above, in S207, the detected temperature (temperature T11) during the cyclic drive in S201 to S203 is compared with the detected temperature (temperature T12) during the cyclic drive in S204 to S206. Furthermore, if it is determined in S207 that T12 > T11, then in S207, the temperature detected during the first cyclic drive in S204 to S206 is compared with the temperature detected during the second cyclic drive in S204 to S206. In other words, in the seventh embodiment, the second energy generating element 24 is driven and cyclic drive is performed based on the detected temperatures detected by the temperature sensing element 34 before and after driving the second energy generating element 24. By comparing the temperatures detected before and after the cycle in the manner described above, it can be determined whether to continue or end the cycle, and the cycle quantity can be controlled. Such temperature comparison can be performed by incorporating a comparison circuit into the liquid injection head 1.

[0159] As described above, in the configuration according to the seventh embodiment, the circulation amount can also be controlled by executing a thickening detection drive. Therefore, by detecting the ink thickening status in the channel based on the detection result of the temperature detection element 34 and feeding the detection result back to the circulation drive, the circulation drive can be executed by driving the second energy generating element 24 in a manner that prevents the circulation amount from becoming excessive. Thus, since the circulation amount in each nozzle can be suppressed, the progression of ink thickening accompanied by excessive circulation in the individual channel 23 can be suppressed.

[0160] The advantage of configuring the cyclic control within the liquid injection head 1 is that cyclic quantity control can be performed solely through the liquid injection head 1 without generating the load associated with data transmission between the liquid injection head 1 and the liquid injection device 50.

[0161] Although this disclosure has been described with reference to embodiments, it should be understood that this disclosure is not limited to the disclosed embodiments. The scope of the following claims is to be interpreted in the broadest sense to cover all such modifications and equivalent structures and functions.

Claims

1. A liquid injection device, comprising: A channel forming section, the channel forming section including a jet opening through which liquid is ejected, a pressure chamber communicating with the jet opening, and an independent channel communicating with the pressure chamber; A first energy generating element is disposed at a position corresponding to the pressure chamber of the channel forming portion, and generates energy for ejecting liquid through the injection opening; A second energy generating element is disposed at a position corresponding to the independent channel of the channel forming portion, and generates energy for transferring liquid through the independent channel; A temperature detection unit, configured to detect temperature, is located at a position corresponding to the first energy generating element or the second energy generating element; and The control unit is configured to control the driving of the second energy generating element based on the detection result of the temperature detection unit.

2. The liquid injection device according to claim 1, in, The control unit controls the driving of the second energy generating element based on a comparison result of comparing the detected temperature detected by the temperature detection unit with a predetermined threshold.

3. The liquid injection device according to claim 1, in, The control unit controls the driving of the second energy generating element based on the time when the detected temperature changes suddenly, as detected by the temperature detection unit.

4. The liquid injection device according to claim 1, in, The control unit controls the driving of the second energy generating element based on the corresponding detected temperatures detected by the temperature detection unit before and after the second energy generating element is driven.

5. The liquid injection device according to claim 1, in, The first energy generating element is disposed at a position overlapping the injection opening in a first direction, and the temperature detection unit is disposed at a position overlapping the first energy generating element in the first direction.

6. The liquid injection device according to claim 5, in, The control unit is capable of performing a thickening detection drive for detecting thickening of liquid in the independent channel by driving the first energy generating element, and controlling the drive of the first energy generating element such that the amount of energy generated by the first energy generating element during the thickening detection drive is less than the amount of energy generated during the jetting drive for jetting liquid from the jet opening.

7. The liquid injection device according to claim 5, in, When the viscosity of the liquid in the independent channel is normal, and the temperature in the independent channel suddenly drops as the first energy generating element is driven, the temperature detection unit detects the temperature in the independent channel.

8. The liquid injection device according to claim 1, in, The first energy generating element is disposed at a position overlapping the injection opening in a first direction, and the temperature detection unit is disposed at a position overlapping the second energy generating element in the first direction.

9. The liquid injection device according to claim 8, in, When the viscosity of the liquid in the independent channel is normal, and the temperature in the independent channel suddenly drops as the second energy generating element is driven, the temperature detection unit detects the temperature in the independent channel.

10. The liquid injection device according to claim 1, in, The first energy generating element and the second energy generating element are disposed at positions corresponding to the independent channel, and the independent channel has a U-shaped configuration extending from the position corresponding to the second energy generating element to the position corresponding to the first energy generating element.

11. The liquid injection device according to claim 10, in, The first energy generating element and the second energy generating element are disposed at a position overlapping the independent channel in a first direction, and the inlet and outlet of the independent channel are adjacent to each other in a second direction intersecting the first direction.

12. The liquid injection device according to claim 1, in, The first energy generating element and the second energy generating element are disposed at positions corresponding to the independent channel, and the independent channel has a linear shape extending from the position corresponding to the second energy generating element to the position corresponding to the first energy generating element.

13. The liquid injection device according to claim 1, in, The first energy generating element and the second energy generating element are disposed at positions corresponding to the independent channel, and the independent channel is divided into two branches from the position corresponding to the second energy generating element to the position corresponding to the first energy generating element.

14. The liquid injection device according to claim 1, in, The channel forming portion includes a plate member and a substrate, the plate member having the injection opening and forming part of the inner wall of the independent channel, and the substrate being connected to the plate member and forming part of the inner wall of the independent channel.

15. The liquid injection device according to claim 1, further comprising: A liquid injection head, the liquid injection head having the channel forming portion, and being provided with a first energy generating element, a second energy generating element and the temperature detection portion; and A conveying unit that conveys the recording medium at a position facing the jet opening.

16. The liquid injection device according to claim 1, in, At least one of the first energy generating element and the second energy generating element is a thermoelectric transducer.

17. A liquid injection head, comprising: A channel forming section, the channel forming section including a jet opening through which liquid is ejected, a pressure chamber communicating with the jet opening, and an independent channel communicating with the pressure chamber; A first energy generating element is disposed at a position corresponding to the pressure chamber of the channel forming portion, and generates energy for ejecting liquid through the injection opening; A second energy generating element is disposed at a position corresponding to the independent channel of the channel forming portion, and generates energy for transferring liquid through the independent channel; A temperature detection unit configured to detect temperature and located at a position corresponding to the first energy generating element or the second energy generating element; and a control unit configured to control the driving of the second energy generating element based on the detection result of the temperature detection unit.

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