Inkjet recording device and its control method

Abstract

In an inkjet recording device, an appropriate drive pulse is used according to the ink temperature. [Solution] The recording means includes a recording element array in which a plurality of recording elements are arranged in a predetermined direction, a first drive circuit for driving the recording elements of a first recording element group, a second drive circuit for driving the recording elements of a second recording element group, a first temperature sensor group along the first recording element group, and a second temperature sensor group along the second recording element group. A first representative temperature is determined based on one or more first temperature information obtained from one or more temperature sensors in the first temperature sensor group at positions corresponding to the recording element area used by the first recording element group, a second representative temperature is determined based on one or more second temperature information obtained from one or more temperature sensors in the second temperature sensor group at positions corresponding to the recording element area used by the second recording element group, a drive pulse to be applied to the first drive circuit is determined based on the first representative temperature, and a drive pulse to be applied to the second drive circuit is determined based on the second representative temperature.

Description

Technical Field

[0001] The present invention relates to recording control in an inkjet recording apparatus.

Background Art

[0002] An inkjet recording apparatus that records an image by discharging ink onto a recording medium while scanning a recording head having a plurality of nozzle arrays with respect to the recording medium has been conventionally known. The recording head arranges recording elements corresponding to a plurality of nozzles, and discharges ink by generating thermal energy with the recording elements. Patent Document 1 discloses a technique for suppressing fluctuations in the ink discharge amount by selecting drive pulses applied to the recording elements according to the temperature of the ink in an inkjet recording apparatus.

[0003] In addition, in an inkjet recording apparatus, an improvement in the recording speed is required. In order to improve the recording speed of a serial scanning type inkjet recording apparatus, it is effective to increase the length of the nozzle array in order to increase the recording area that can be recorded on the recording medium in one scan (head movement). However, as the nozzle array is extended, the length of the recording element substrate itself becomes longer, and problems such as a deviation in the operation timing due to signal delay may occur. Patent Document 2 discloses a method of configuring circuit blocks on a recording element substrate as two independent blocks electrically separated with the vicinity of the center in the longitudinal direction of the recording element substrate as a boundary. As a result, a recording element substrate having an electrical recording element substrate length that is actually half the length is obtained, and the influence of a deviation in the operation timing and the like is reduced.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

[0005] However, problems can arise in recording modes that separate and use only certain nozzle areas vertically around the nozzle row (such as modes for controlling the ink recording order). For example, if the maximum ink density per unit area (image duty cycle) differs between the upper and lower parts of the nozzle row, the ink temperature rise distribution will also differ between the upper and lower parts. In this case, a discrepancy is likely to occur between the representative temperature and the actual temperature around the nozzles being used. As a result, it may not be possible to apply appropriate pulses, which could lead to image defects such as unevenness or in-machine contamination (mist).

[0006] This invention has been made in view of the above problems, and aims to provide a technology that enables the use of appropriate drive pulses according to the ink temperature in an inkjet recording device. [Means for solving the problem]

[0007] To solve the above-mentioned problems, the inkjet recording apparatus according to the present invention has the following configuration. That is, the inkjet recording apparatus is A recording means, A recording element array in which multiple recording elements, each generating thermal energy for ejecting ink, are arranged in a predetermined direction, A first drive circuit that drives the recording elements of the first group of recording elements included in the aforementioned recording element array, A second drive circuit that drives recording elements of a second recording element group which is included in the aforementioned recording element array and does not overlap with the first recording element group, A first group of temperature sensors for detecting the temperature at multiple locations along the first group of recording elements, A second group of temperature sensors for detecting the temperature at multiple locations along the second group of recording elements, The recording means includes, An acquisition means for acquiring temperature information obtained from the first temperature sensor group and the second temperature sensor group, A determination means for determining the drive pulses to be applied to the first drive circuit and the second drive circuit based on a representative temperature determined based on the temperature information acquired by the acquisition means, Equipped with, The determination means, in a first recording mode in which recording is performed using at least some of the recording elements of the first recording element group and at least some of the recording elements of the second recording element group, A first representative temperature is determined based on one or more first temperature information obtained from one or more temperature sensors in the first temperature sensor group at positions corresponding to the recording element area used by the first recording element group, and a second representative temperature is determined based on one or more second temperature information obtained from one or more temperature sensors in the second temperature sensor group at positions corresponding to the recording element area used by the second recording element group. The drive pulse applied to the first drive circuit is determined based on the first representative temperature, and the drive pulse applied to the second drive circuit is determined based on the second representative temperature. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a technology that enables the use of appropriate drive pulses according to the ink temperature in an inkjet recording device. [Brief explanation of the drawing]

[0009] [Figure 1] This is a perspective view of an inkjet recording device. [Figure 2] This is a schematic diagram of the recording head. [Figure 3] These are a perspective view and a cross-sectional view of the recording element substrate. [Figure 4] This diagram shows the circuit block of a recording element substrate. [Figure 5] This is a diagram showing the configuration of the recording and control system. [Figure 6] This is a diagram illustrating the drive pulse (double pulse). [Figure 7] This figure shows the relationship between various parameters and ink ejection volume. [Figure 8]This is a diagram for explaining drive pulses corresponding to each ink temperature. [Figure 9] This is a diagram showing the relationship between ink temperature and ink ejection amount when drive pulse control is performed. [Figure 10] This is a diagram for explaining the determination of representative temperature (First Embodiment). [Figure 11] This is a flowchart showing drive pulse control processing (First Embodiment). [Figure 12] This is a diagram for explaining the determination of representative temperature (Second Embodiment). [Figure 13] This is a flowchart showing drive pulse control processing (Third Embodiment). [Figure 14] This is a diagram showing an example of a method for adjusting drive conditions. [Figure 15] This is a diagram for explaining the configuration of a recording layer in five-layer recording. [Figure 16] This is a diagram for explaining the determination of representative temperature (Fourth Embodiment). [Figure 17] This is a flowchart showing drive pulse control processing (Fourth Embodiment).

Best Mode for Carrying Out the Invention

[0010] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the invention according to the claims. Although a plurality of features are described in the embodiments, not all of these plurality of features are essential for the invention, and the plurality of features may be arbitrarily combined. Further, in the accompanying drawings, the same or similar configurations are denoted by the same reference numerals, and redundant descriptions are omitted.

[0011] (First Embodiment) As a first embodiment of an inkjet recording apparatus according to the present invention, a serial scanning type inkjet recording apparatus will be described below as an example.

[0012] <Device Configuration> Figure 1 shows an external perspective view of an inkjet recording device (printer). This is a so-called serial scanning printer, which records an image (ink image) on the recording medium P by scanning the recording head in an intersecting direction (X direction) perpendicular to the transport direction (Y direction) of the recording medium P.

[0013] This document outlines the configuration and recording operation of this inkjet recording device. First, the recording medium P is transported in the Y direction from the spool 6, which holds the recording medium P, by transport rollers driven via gears by a transport motor (not shown). Meanwhile, at a predetermined transport position, the carriage unit 2 is scanned along a guide shaft 8 extending in the X direction by a carriage motor (not shown). During this scanning process, based on the position signal obtained by the encoder 7, the recording head (Figure 2), which is detachably mounted on the carriage unit 2, performs an ejection operation from its nozzle, recording a certain bandwidth corresponding to the arrangement range of the ejection nozzles. In this embodiment, the device is configured to scan at a scanning speed of 40 inches per second and perform recording at a resolution of 600 dpi. After that, the recording medium P is transported, and then recording is performed for the next bandwidth.

[0014] In such printers, an image may be recorded on a unit area of ​​the recording medium in a single scan (so-called one-pass recording), or in multiple scans (so-called multi-pass recording). When performing one-pass recording, the recording medium may be transported by the bandwidth between each scan. When performing multi-pass recording, instead of transporting the recording medium after each scan, there is a method in which the unit area of ​​the recording medium is scanned multiple times, and then transported by approximately one band to that unit area. Alternatively, data that has been downsampled by a predetermined mask pattern is recorded after each scan, and then the paper is transported by approximately 1 / n bands (where n is the number of scans), and then scanned again. In this method, the image is completed by multiple (n) scans and transports on a unit area of ​​the recording medium with a different number of nozzles involved in recording.

[0015] A flexible wiring board 5 is attached to the recording head to supply signal pulses for ejection drive and signals for head temperature control. The other end of the flexible wiring board 5 is connected to a control circuit that controls the printer.

[0016] The printer is also equipped with an internal temperature sensor (not shown) for detecting the internal temperature near the recording head.

[0017] A carriage belt can be used to transmit the driving force from the carriage motor to the carriage unit 2. However, other drive systems can also be used instead of a carriage belt, such as a system comprising a lead screw that is rotationally driven by the carriage motor and extends in the X direction, and an engaging part provided on the carriage unit 2 that engages with the groove of the lead screw.

[0018] The fed recording medium P is held and transported by the feed roller and pinch roller and guided to the recording position on the platen 4 (the main scanning area of ​​the recording head). Normally, in the idle state, the face of the recording head is capped, so prior to recording, the cap is opened to make the recording head or carriage unit 2 scannable. After that, once enough data for one scan has been accumulated in the buffer, the carriage motor is used to scan the carriage unit 2 and perform the recording.

[0019] Figure 2 is a schematic perspective view of the recording head 9. The recording head 9 has a joint portion 25, which is connected to an ink supply path extending from an ink tank (not shown) located away from the recording head 9. Ink is supplied from the ink tank to the inside of the recording head 9 via the ink supply path and the joint portion 25.

[0020] Furthermore, two recording element substrates 10a and 10b, made of semiconductors or the like, are attached to the nozzle-forming surface of the recording head 9, which is the surface facing the recording medium P. Nozzle rows are formed on each of the recording element substrates 10a and 10b along the Y direction (a predetermined direction) perpendicular to the X direction. Nozzle rows 11 to 18 that eject ink of different tones (including color and density) are arranged in the X direction on the recording element substrates 10a and 10b. For example, each nozzle row is configured to eject one of the following color inks: white (W), black (K), cyan (C), magenta (M), or yellow (Y). Alternatively, one or more nozzle rows may be configured to eject an ink such as a transparent reaction liquid that, when brought into contact with the color ink on the recording medium, causes aggregation of the colorants in the color ink and suppresses image blurring. Recording element rows are formed within the recording element substrates 10a and 10b corresponding to each of the nozzle rows 11 to 18, as will be described later.

[0021] Figure 3(a) is a perspective view of the recording element substrate 10a as seen from a direction perpendicular to the XY plane. Figure 3(b) is a cross-sectional view of the vicinity of the nozzle row 11 on the cut surface, as seen from the downstream side in the Y direction, when the recording element substrate 10a is cut perpendicular to the surface of the recording element substrate 10a through the line segment AB shown in Figure 3(a).

[0022] In this embodiment, nozzle rows 11 to 18 are each formed from two rows. These two rows are arranged with a 1 / 1200 inch offset in the Y direction, enabling recording at 1200 dpi. In addition, multiple nozzles 30 and recording elements (main heaters) 34, which are electrothermal conversion elements facing the nozzles 30, are similarly arranged in the Y direction. By applying pulses to these recording elements 34 according to the image data, thermal energy for ejecting ink from the nozzles 30 can be generated. Electrical pads 103 and 104 are individually wired to each nozzle row of the recording element rows, and electrical signals and heater currents for ejection are transmitted to the recording elements 34.

[0023] This description focuses on the use of an electrothermal conversion element as the recording element, but piezoelectric elements and other types can also be used. Furthermore, while there are configurations that include so-called dummy nozzles that do not contribute to ink ejection, in addition to the nozzles used for image recording, these will not be explained here.

[0024] Furthermore, multiple temperature sensors 44, each consisting of a diode, are arranged on the recording element substrate 10a in the direction of the recording element arrangement in order to detect the temperature at different locations within the recording element substrate.

[0025] In this embodiment, the temperature of the ink in the nozzle near the temperature sensor 44 is approximately the same as the temperature of the recording element substrate 10a at the location where the temperature sensor 44 is installed; therefore, the temperature of the recording element substrate 10a is treated as the ink temperature.

[0026] Furthermore, multiple heating elements (subheaters) 45 for heating the ink temperature inside the nozzles are arranged on the recording element substrate 10a in the direction of the recording element arrangement 34, sandwiching the recording element 34. The material used for the heating elements 45 is a material that generates heat when an electric current is passed through it, such as aluminum.

[0027] As shown in Figure 3(b), the recording element substrate 10a consists of a circuit board 31 on which various circuits, including a temperature sensor 44 and a heating element 45, are formed, and a nozzle member 35 made of resin. A common ink chamber 33 is formed between the circuit board 31 and the nozzle member 35, and an ink supply port 32 communicates with the common ink chamber 33. An ink flow path 36 extends from the common ink chamber 33 and communicates with a nozzle 30 formed on the nozzle member 35. A foaming chamber 38 is formed at the nozzle 30 side end of the ink flow path 36, and a recording element (main heater) 34 is positioned in the foaming chamber 38 opposite the nozzle 30. A nozzle filter 37 is also formed between the ink flow path 36 and the common ink chamber.

[0028] Although the recording element substrate 10a has been described in detail here, the recording element substrate 10b has a nearly identical configuration.

[0029] <Regarding the circuit configuration of the recording element substrate> Figure 4 shows a circuit block representing one row of nozzle rows 11 to 18 on the recording element substrate 10.

[0030] The dashed line 102 is illustrative and illustrative for illustrative purposes, showing the center line of the nozzle row on the recording element substrate 10, and does not actually exist on the substrate. Pads 103a to 103h and 104a to 104h for electrical connections with the outside are located on one end of the substrate in the same direction as the nozzle row. Each pad is assigned a signal terminal for transferring image data from the outside to the recording element substrate 10, and a power terminal for driving the element.

[0031] The signals supplied from the pads are supplied to independent circuit blocks, and in this embodiment, they are separated by the center line. However, this separation does not necessarily have to be at the center line.

[0032] First, let's briefly explain the operation of the circuit block on the left. Serial data representing image data is input to the DATA terminal of pad 103d from an external source. This DATA signal is input in synchronization with the CLK signal input to pad 103c.

[0033] These DATA and CLK signals are input to the shift register 106a via an input circuit 105a equipped with an electrostatic protection circuit. Here, the signal input to the shift register 106a is performed from the outside of the nozzle row toward the center, that is, from left to right in the figure. After inputting the required number of serial data to the shift register 106a, a latch signal is input to pad 103f to store the data in a latch circuit for temporarily holding this serial data. The signal is transmitted to the latch circuit included in the shift register 106a via input circuit 105b. Here, the signal held in the latch circuit is output to the AND array 108a to determine an arbitrary recording element 34, and the other part is output to the decoder 107a for further decoding. The decoder 107a decodes the input signal from the shift register 106a and outputs the decoded signal to the AND array 108a.

[0034] The AND array is a circuit in which AND circuits are arranged in an array, with a number of AND gates corresponding to the number of nozzles and recording elements. Each circuit performs an AND operation on the signal from the shift register 106a and the signal from the decoder 107a, and the recording element array 34a whose result of this AND operation is true is selected.

[0035] The time required to heat the ink is input to pad 103g as a pulse-shaped HE signal and output to AND array 108a via input circuit 105c.

[0036] The AND array performs an AND operation with the previously selected recording element and the HE signal. If the result of this AND operation is true, the driver circuit of the driver array 109a corresponding to the recording element is turned ON. When it is turned ON, current flows to the recording element of the corresponding recording element row 34a, heating and foaming the ink, and ejecting the ink.

[0037] On the other hand, the circuit block on the right side of the recording element substrate 10 operates in a similar manner. The signal input to the shift register 106b is the same as described above, except that it is performed from the outside of the recording element array toward the center, that is, from right to left in the diagram, so the explanation is omitted here.

[0038] Furthermore, the ink is introduced from a common ink supply port 32 formed on the recording element substrate 10 to the entire area of ​​the nozzle 30 formed on the recording element substrate 10. Note that the shape, number, and position of this ink supply port may be different from those shown in this figure.

[0039] As described above, in the recording element substrate 10, the pad and recording element drive circuits are completely separated in the left and right halves of the center of the recording element array, or in other words, in the upper and lower halves with respect to the recording medium transport direction Y. This means that it is possible to provide separate HE signals to the non-overlapping recording element arrays 34a and 34b.

[0040] Figure 5 shows the configuration of the control system of the inkjet recording device. The programmable peripheral interface (PPI) 101 receives command signals and recording information signals, including recording data, sent from the host computer 100 and transfers them to the MPU 102. The PPI 101 also sends printer status information to the host computer 100 as needed. The PPI 101 also performs input and output with the console 126, which has a setting input unit for the user to make various settings for the printer and a display unit for displaying messages to the user. In addition to input and output with the console 126, the PPI 101 also receives input signals from a sensor group 127, including a home position sensor that detects whether the carriage unit 2 or the recording head 9 is in the home position, and a capping sensor.

[0041] The MPU (microprocessing unit) 102 controls various parts of the printer according to the control program stored in the control ROM 125. The RAM 123 is a memory that stores received signals, is used as the work area of ​​the MPU 102, and temporarily stores various data. The font generation ROM 124 stores pattern information such as characters and records corresponding to code information, and outputs various pattern information corresponding to the input code information. The print buffer 121 is a buffer for storing recorded data expanded in the RAM 123, etc., and has a capacity for recording multiple lines. In addition to the control program, the control ROM 125 can store fixed data corresponding to data used in the control process (for example, data for the MPU to determine the start timing of subheater control, which will be described later). Each of these parts is controlled by the MPU 102 via the address bus 117 and the data bus 118. The MPU 102 also acquires the temperature detected from each of the temperature sensors 44 located in the recording head 9 and generates the above-mentioned program data based on these temperatures.

[0042] Motor drivers 114, 115, and 116 drive the capping motor 113, carriage motor 3, and paper feed motor 5, respectively, according to the control of the MPU 102.

[0043] The sheet sensor 109 detects the presence or absence of a recording medium, that is, whether or not the recording medium has been supplied to a position where it can be recorded by the recording head 9. The driver 111 drives the heating elements (main heater, sub-heater) of the recording head 9 according to the data. The temperature and humidity sensor 122 detects the ambient temperature and humidity in the environment in which the printer body is installed. The power supply unit 124 supplies power to each part and has an AC adapter or battery as a drive power supply device.

[0044] In the printer's recording system, when recording data is transmitted from the host computer 100 via a parallel port, infrared port, or network, the necessary commands are added to the beginning of the transmission data. These commands may include, for example, the type of recording medium to be used (plain paper, glossy paper, etc.), the medium size (A0, B1, etc.), the recording quality (draft, high quality, etc.), and the paper feed path. The paper feed path can be selected from options such as an automatic sheet feeder (ASF), manual feed, paper cassette 1, and paper cassette 2. The commands may also include settings for whether or not to automatically detect objects. Furthermore, if a configuration is adopted to apply a processing liquid to improve ink fixation on the recording medium, information determining whether or not to apply this liquid may also be transmitted as a command.

[0045] In accordance with these commands, the printer reads the necessary data for recording from the aforementioned ROM125 and performs recording based on that data. This data includes, for example, the number of recording passes when performing multi-pass recording as described above, the amount of ink to be printed per unit area of ​​the recording medium, and the recording direction. In addition, there are other parameters such as the type of mask used for data decimation when performing multi-pass recording, the driving conditions of the recording head 9 (for example, the shape and duration of the drive pulse applied to the heat-generating part), the dot size, the conditions for transporting the recording medium, the number of colors used, and the carriage speed.

[0046] <Drive pulse control> The inkjet recording apparatus according to this embodiment performs drive pulse control, as described later, according to the ink temperature. In this embodiment, during scanning of the recording head 9, one of a plurality of drive pulses is selected according to the ink temperature and applied to the recording element 34 as an HE signal. This causes the recording element 34 to heat up, and the resulting thermal energy ejects ink, thus performing so-called drive pulse control.

[0047] In this embodiment, the drive pulse control uses a representative temperature for each nozzle row, obtained based on the temperatures detected by multiple temperature sensors 44 for each nozzle row, as the ink temperature. The method for obtaining this representative temperature will be described later.

[0048] In this embodiment, a so-called double pulse, consisting of a pre-pulse and a main pulse, is used as the applied drive pulse.

[0049] Figure 6 illustrates the drive pulse (double pulse). Here, Vop is the drive voltage, P1 is the pulse width of the pre-pulse, P2 is the interval time, and P3 is the pulse width of the main pulse. Ink ejection is controlled by controlling the pulse width of the pre-pulse, so the pre-pulse plays an important role.

[0050] The pre-pulse is a pulse applied primarily to heat the ink temperature near the nozzle, making foaming easier. The pulse width of the pre-pulse is set to a value such that the pulse width is less than or equal to the energy value at the foaming boundary of the ink. The interval time is a fixed time interval between the pre-pulse and the main pulse, and is set to allow sufficient time for the heat generated by the application of the pre-pulse to be transferred to the nearby ink. The main pulse is a pulse used to foam the ink and eject ink droplets.

[0051] Figure 7(a) shows the relationship between ink temperature and ink ejection volume when the waveform of the drive pulse applied to the recording element 34 and the drive voltage Vop are fixed. From Figure 7(a), it can be seen that the ink ejection volume increases as the ink temperature rises.

[0052] Figure 7(b) shows the relationship between the pre-pulse pulse width and the ink discharge volume when the interval time and drive voltage Vop are fixed, under the condition that the ink temperature is the same. From Figure 7(b), it can be seen that as the pre-pulse pulse width P1 is increased, the ink discharge volume Vd also increases proportionally. As the pre-pulse pulse width P1 increases and the amount of energy supplied by the pre-pulse increases, the ink temperature rises, and the ink viscosity decreases accordingly. When the main pulse is applied when the ink viscosity has decreased, the ink discharge volume increases. Conversely, when the main pulse is applied when the ink viscosity has not decreased significantly, the ink discharge volume decreases.

[0053] Therefore, in this embodiment, fluctuations in the amount of ink ejected due to changes in substrate temperature (ink temperature) are suppressed by changing the pulse width of the prepulse according to the ink temperature. Specifically, when the ink temperature is relatively low, there is a risk that the amount of ink ejected will decrease, so the pulse width P1 of the prepulse of the drive pulse applied to the recording element is made relatively large. This makes it possible to suppress a decrease in the amount of ink ejected. Similarly, when the ink temperature is relatively high, the pulse width P1 of the prepulse is made relatively small.

[0054] Figure 8 illustrates the drive pulses used depending on the ink temperature. For example, as shown in Figure 8(b), when the ink temperature is relatively low, below 20°C, drive pulse "No. 6" with a relatively large pulse width P1 of the pre-pulse shown in Figure 8(a) is selected. On the other hand, when the ink temperature is relatively high, above 70°C, drive pulse "No. 0" with a relatively small pulse width P1 of the pre-pulse shown in Figure 8(a) is selected.

[0055] Figure 9 shows the correlation between ink temperature and ink ejection volume when a drive pulse is selected and applied as shown in Figures 8(a) and (b). Within the temperature range shown in Figure 9, from 30°C to 40°C, drive pulse "No. 4" is applied to the recording element, as can be seen from Figure 8(b). Within this temperature range, as shown in Figure 7(a), the ink ejection volume increases as the ink temperature rises.

[0056] When the ink temperature exceeds 40°C, the applied drive pulse is changed from drive pulse "No. 4" to drive pulse "No. 3," which has a shorter pre-pulse pulse width. Therefore, as can be seen from Figure 8, the amount of ink ejected can be reduced. In this way, by performing PWM control, it is possible to suppress fluctuations in the amount of ink ejected and record even when there is a change in the ink temperature.

[0057] <Method for obtaining representative temperature> In this embodiment, for each half of the nozzle row's transport direction Y, only the temperature information from the temperature sensor corresponding to the nozzle used for recording is selected from the temperature information acquired by the temperature sensor 44, and a representative temperature during drive pulse control is determined. This process will be described in detail below.

[0058] Figure 10 illustrates the determination of the representative temperature in the first embodiment. Figure 10(a) shows an example of the nozzle area used in a certain recording mode and the arrangement of the temperature sensor 44 in one row of nozzles, the maximum ink injection amount per unit area for each nozzle (image duty), and the substrate temperature distribution during the same recording. Figure 10(b) shows an example of the temperature information acquired by the temperature sensors 44a to 44j during the recording in Figure 10(a), and Figure 10(c) shows an example of the selection of the temperature sensor 44 (one or more temperature sensors) used to determine the representative temperature during pulse control in the recording in Figure 10(a).

[0059] As shown in Figure 10(a), the nozzles 30 are arranged in the y-direction, and the recording elements 34 are also arranged corresponding to the nozzles. The row of nozzles 30 is divided into two regions with respect to the center line, and these two regions are referred to as the first nozzle group and the second nozzle group, respectively. The first and second nozzle groups do not overlap. The first drive circuit is wired to the recording elements corresponding to the first nozzle group, and the second drive circuit is wired to the recording elements corresponding to the second nozzle group. In the following explanation, we are referring to the nozzle groups divided with respect to the nozzles 30, but we may also refer to the recording element groups corresponding to each nozzle group.

[0060] The temperature sensors 44 are arranged at approximately equal intervals in the array direction, with one sensor space between each group of recording elements. In the inkjet recording apparatus according to this embodiment, by storing information on the temperature sensor number corresponding to each recording element in advance, it is possible to select the corresponding temperature sensor according to the nozzle and recording element information used for recording. For convenience, the group of temperature sensors 44 in the region corresponding to the first group of nozzles is referred to as the first group of temperature sensors. The group of nozzles located below the center line is referred to as the second group of nozzles, and the group of temperature sensors 44 in the corresponding region is referred to as the second group of temperature sensors.

[0061] Incidentally, in a recording head with multiple recording elements arranged at high density, energy for ejection is generated by rapidly heating each individual recording element. Therefore, the higher the high-frequency drive ejection state, i.e., the higher the image duty cycle, the more heat accumulates in the recording head and the higher its temperature becomes. When not used for recording, i.e., when the recording elements are not driven, no temperature change occurs.

[0062] From the above, as shown in Figure 10(a), in a recording mode that uses at least some of the nozzles of the first nozzle group and the second nozzle group, the temperature near the nozzles not used for recording is low, and the temperature near the nozzles used for recording is high. Furthermore, if the image duty cycle differs between the first nozzle group and the second nozzle group, the temperature rise distribution near the nozzles in the used area will differ for each.

[0063] In this case, it is also possible to use the average temperature of the temperatures acquired by all temperature sensors 44a to 44j in both the first and second temperature sensor groups as the representative temperature. For example, the representative temperature could be set to 37°C (=(30+30+50+50+30+30+60+30+30+30) / 10)°C. However, in this case, temperatures in the lower parts that are not used for recording will also be included, resulting in a discrepancy between the recorded temperature and the actual temperature of the part being used.

[0064] Alternatively, the average temperature obtained by temperature sensors 44c, 44d, and 44g, which correspond to the nozzle area (recording element area) used by the first and second temperature sensor groups combined, can be used as the representative temperature. For example, the representative temperature could be set to 53.3°C (=(50+50+60) / 3). However, even in this case, there will be a slight discrepancy between the actual temperature in each of the first and second nozzle area regions and the representative temperature obtained, so if drive pulse control is performed using the obtained representative temperature, there is a risk that the amount of ink ejected from the recording element will be excessive or insufficient.

[0065] Therefore, in this embodiment, one or more temperature information from one or more temperature sensors corresponding to the nozzle area used by the first nozzle group is selected from the first temperature sensor group to determine the first representative temperature. In addition, one or more temperature information from one or more temperature sensors corresponding to the nozzle area used by the second nozzle group is selected from the second temperature sensor group to determine the second representative temperature. For example, as shown in Figure 10(c), temperature sensors 44c and 44d are selected for the first nozzle group, and temperature sensor 44g is selected for the second nozzle group to determine the representative temperature for each. For example, the representative temperature for the first nozzle group (first representative temperature) is 50 (= (50 + 50) / 2) °C, and the representative temperature for the second nozzle group (second representative temperature) is 60 °C.

[0066] In this manner, the nozzle row is divided into two upper and lower regions, and a temperature sensor corresponding to the nozzle region being used is selected for each region. Drive pulse control is then performed based on the calculated representative temperature. This allows for more precise suppression of excessive or insufficient discharge volume from each nozzle.

[0067] In this example, the representative temperature is the average value of one or more temperature data points obtained by one or more temperature sensors 44, but the maximum or minimum value may also be used. Furthermore, although the explanation uses one nozzle row as an example, the representative temperature during drive pulse control for each nozzle row is obtained using the same process for other rows.

[0068] <Drive pulse control based on typical temperature> Figure 11(a) is a flowchart showing the drive pulse control process in the first embodiment. Specifically, it shows the process of acquiring a representative temperature and drive pulse control based on that representative temperature. In this embodiment, the drive pulse control shown in Figure 11(a) is performed at predetermined time intervals (e.g., every 5ms) while the image is being recorded.

[0069] In step S1101, the MPU 102 starts drive pulse control. First, in step S1102, recording mode information is acquired.

[0070] In step S1103, the MPU 102 selects a nozzle region. For example, it selects one nozzle region from among the 16 regions of nozzle rows 11a to 18a and 11b to 18b shown in Figure 11(b).

[0071] In step S1104, the MPU 102 obtains information about the nozzle area to be used for recording from the recording mode. In step S1105, the MPU 102 selects a temperature sensor 44 corresponding to the nozzle used for recording in order to obtain a representative temperature of the selected nozzle area. In step S1106, the MPU 102 obtains the temperature information corresponding to the temperature sensor selected in S1105 from among the temperature information obtained from multiple temperature sensors stored in the RAM 103. Note that the RAM 103 is configured to update the temperature information from each temperature sensor 44 with the latest value in real time.

[0072] In step S1107, the MPU 102 performs the averaging process described above on the temperature information acquired in S1106 to calculate a representative temperature during drive pulse control. In step S1108, the MPU 102 determines the drive pulse to be applied to the drive circuit based on the representative temperature during drive pulse control calculated in S1107. For example, it determines one drive pulse from among the multiple drive pulses No. 0 to No. 6 shown in Figure 8(a) stored in the ROM 105.

[0073] In step S1109, the MPU 102 determines whether the drive pulse determination process has been performed in all nozzle row regions (in this case, 16 regions: regions 11a to 18a and 11b to 18b). If it is determined that there are still nozzle regions where the drive pulse determination process has not been performed, the process returns to S1103 and the same process is performed for the other nozzle regions. If it is determined that the drive pulse determination process has been performed in all nozzle regions, the drive pulse control is terminated (S1110). The head driver 111 applies the drive pulses determined as described above to the recording elements located in each nozzle region to perform recording.

[0074] As described above, according to the first embodiment, a representative temperature is determined for each divided region on the same nozzle row, and a drive pulse is selected and used for each region based on the representative temperature. This makes it possible to use an appropriate drive pulse according to the ink temperature for image recording, thereby reducing image defects such as unevenness and the occurrence of in-machine contamination (mist).

[0075] (Second Embodiment) In the second embodiment, depending on the recording mode, the method is described in which the recording mode is determined from the temperature acquired by the temperature sensor 44 corresponding to the nozzle used for recording across the entire nozzle row, including the first and second nozzle groups.

[0076] Some recording modes use a wide range of nozzles, spanning both the upper and lower nozzle rows, for recording. In such cases, it is preferable to select and determine the temperature sensor 44 corresponding to the nozzle being used within the combined area of ​​the first and second nozzle groups, and then apply the drive pulse signal determined from the representative temperature to the drive circuits above and below the nozzle row, respectively. This is because, since a single scan recording is performed using a nozzle area spanning both the upper and lower nozzle rows, if the representative temperature and drive pulse conditions obtained with the center of the nozzle row as the boundary differ significantly, unevenness may occur with the center of the nozzle row as the boundary.

[0077] The device configuration and drive pulses are the same as those of the first embodiment described above, so their explanation will be omitted. Below, we will mainly explain the parts of the representative temperature that differ from the first embodiment.

[0078] Figure 12 illustrates the determination of the representative temperature in the second embodiment. Figure 12(a) shows an example of the nozzle area used in a certain recording mode and the arrangement of the temperature sensor 44 in one row of nozzles, the maximum ink injection amount per unit area for each nozzle (image duty), and the substrate temperature distribution during the same recording. Figure 12(b) shows an example of the temperature information acquired by the temperature sensors 44a to 44j during the recording in Figure 12(a), and Figure 12(c) shows an example of the selection of the temperature sensor 44 used to determine the representative temperature during pulse control in the recording in Figure 12(a).

[0079] As shown in Figure 12(a), in the recording mode where nozzles are used across the first and second nozzle groups, a temperature distribution is formed where the heating portion is not separated. In this case, if a representative temperature is determined for each nozzle group as in the first embodiment, the first representative temperature is 46°C (=(30+50+50+50+50) / 5)°C, by selecting temperature sensors 44a to 44e from the first temperature sensor group. The second representative temperature is 50°C, by selecting temperature sensor 44f from the second temperature sensor group. In that case, as shown in Figure 8(b), the first drive circuit is assigned the drive pulse "NO.3", and the second drive circuit is assigned the drive pulse "NO.2". That is, because the driving conditions change above and below the nozzle row for a temperature distribution where the heating portion is connected as one, the amount of ink ejected changes significantly near the center line of the nozzle row, which may result in noticeable unevenness.

[0080] Therefore, in the second embodiment, the temperature of the temperature sensor corresponding to the usable nozzle area in the entire nozzle row, including the first and second nozzle groups, is selected, and the same representative temperature is determined for both the first and second nozzle groups. For example, as shown in Figure 12(c), temperature sensors 44a to 44f are selected, and the representative temperature for the first and second nozzle groups is set to a common 46.7°C (=(30+50+50+50+50+50) / 6)°C. Subsequently, the drive pulse conditions are determined from the obtained representative temperatures, and the same drive pulse conditions are applied to the first drive circuit corresponding to the first nozzle group and the second drive circuit corresponding to the second nozzle group.

[0081] As described above, according to the second embodiment, in the recording mode where a wide range of nozzles are used for recording across the upper and lower sections of the nozzle row, the same representative temperature is determined for the first nozzle group and the second nozzle group. This suppresses the occurrence of unevenness with the center of the nozzle row as the boundary, while suppressing excessive or insufficient discharge volume from each nozzle with greater precision.

[0082] In this example, the representative temperature is the average value of the temperatures obtained by the temperature sensor 44, but the maximum or minimum value may also be used. Furthermore, although the explanation uses one nozzle row as an example, the representative temperature during drive pulse control for each nozzle row is obtained using the same process.

[0083] (Third embodiment) In the third embodiment, a configuration is described in which, in the control of the first embodiment, the driving conditions are adjusted when the difference between the first representative temperature and the second representative temperature is greater than a predetermined value.

[0084] <Drive pulse control based on typical temperature> Figure 13(a) is a flowchart of the drive pulse control process in the third embodiment. Specifically, it shows the process of acquiring a representative temperature and drive pulse control based on the representative temperature. In this embodiment, the drive pulse control shown in Figure 13(a) is executed every 5ms during image recording. Note that steps S1301 to S1309 are the same as in the first embodiment (S1101 to S1109), so their explanation is omitted.

[0085] In step S1310, the MPU 102 compares the upper and lower representative temperatures (first representative temperature Tabe1 and second representative temperature Tabe2) in the same nozzle row. If the difference ΔT between Tabe1 and Tabe2 is less than or equal to a predetermined value x, the drive pulse control is terminated (S1312). On the other hand, if ΔT is greater than the predetermined value x, the process proceeds to S1311 to mitigate the difference in drive conditions between the upper and lower nozzle rows.

[0086] In step S1311, the MPU 102 adjusts the driving conditions for the first nozzle group and the second nozzle group.

[0087] Figure 14 shows an example of a method for adjusting the drive conditions (S1311). Specifically, it shows an example of a method for adjusting the drive conditions of the first and second drive circuits when ΔT is greater than a predetermined value x. In particular, the temporary drive pulse No. on the higher temperature side of the first representative temperature Tab1 and the second representative temperature Tab2 is shifted to a lower value. Also, the temporary drive pulse No. on the lower temperature side is shifted to a higher value. As a result, the difference in drive conditions between the first and second nozzle groups is reduced.

[0088] As described above, according to the third embodiment, when the temperature difference between the first representative temperature and the second representative temperature is greater than a predetermined value, the drive pulse control is adjusted so that the difference in driving conditions applied to the first drive circuit and the second drive circuit becomes smaller. This makes it possible to suppress the occurrence of unevenness with the center of the nozzle row as the boundary, while suppressing excessive or insufficient ejection volume from each recording element with higher precision.

[0089] (Fourth Embodiment) In the fourth embodiment, the control of drive pulses in an inkjet recording apparatus that forms multiple recording layers on a recording medium using overlapping inks will be described. More specifically, a representative temperature is determined by selecting the temperature of the temperature sensor 44 corresponding to the nozzle area used, excluding the nozzle used for recording the intermediate layer among the multiple recording layers.

[0090] Figure 15 illustrates the configuration of recording layers in five-layer recording. Some recording modes, as shown in Figure 15, involve forming multiple recording layers on a recording medium. Figure 15 illustrates a cross-section of a recording medium (transparent film) with five layers. It consists of five recording layers, arranged in order from the recording medium surface: a first surface layer, a first underlay layer, an intermediate layer, a second underlay layer, and a second surface layer. For example, the surface layer is recorded with non-white ink, the underlay layer with white ink, and the intermediate layer with black ink. By performing such recording, when viewed from below in Figure 15, the pattern recorded on the first surface layer is observed, while when viewed from above, the pattern recorded on the second surface layer is observed. In other words, it is possible to create a recording in which different patterns are observed on both sides of the recording medium.

[0091] <Method for obtaining representative temperature> Figure 16 illustrates the determination of a representative temperature in the fourth embodiment. Figure 16(a) shows an example of the arrangement of the nozzle area used and the temperature sensor 44 in a second nozzle row (black nozzle row) supplied with black ink for intermediate layer recording in a certain recording mode. Figure 16(b) shows an example of the selection of the temperature sensor 44 used for determining the representative temperature during pulse control in the recording in Figure 16(a).

[0092] Here, the rows of nozzles 30 are divided into two regions, upper and lower, with respect to the center line, and these regions are referred to as the third nozzle group and the fourth nozzle group, respectively. The third nozzle group and the fourth nozzle group do not overlap. The recording elements corresponding to the third nozzle group are wired with the third drive circuit, and the recording elements corresponding to the fourth nozzle group are wired with the fourth drive circuit. The group of temperature sensors 44 corresponding to the nozzles within the range of the third nozzle group is called the third temperature sensor group, and the group of temperature sensors 44 corresponding to the nozzle range of the fourth nozzle group is called the fourth temperature sensor group.

[0093] As shown in Figure 16(a), in the 5-layer recording mode, there are two nozzle areas used for surface layer recording (each representing two layers) and one nozzle area used for intermediate layer recording, resulting in a total of three separate areas. Five-layer recording is achieved by recording in these three areas within the same scanning operation while transporting the recording medium in the y-direction. The intermediate layer is a solid black layer sandwiched between two surface layers to prevent the pattern of one surface layer recording from showing through and affecting the image quality of the other surface layer recording. Therefore, the image quality accuracy of the intermediate layer itself does not contribute much to marketability. In other words, when recording the intermediate layer, as long as ejection is occurring, a somewhat lower precision in maintaining the ejection amount is acceptable.

[0094] Therefore, in the fourth embodiment, the temperature of the nozzle region used for recording the intermediate layer is ignored when determining the representative temperature. Specifically, for each of the third and fourth nozzle groups, the temperature of the temperature sensor corresponding to the recording nozzle region, excluding the nozzle used for recording the intermediate layer, is used to determine the representative temperature from the third and fourth temperature sensor groups.

[0095] For example, in the recording mode shown in Figure 16(a), as shown in Figure 16(b), the temperatures acquired by temperature sensors 44a and 44b are selected for calculating the representative temperature of the third nozzle group. Similarly, the temperatures acquired by temperature sensors 44i and 44j are selected for calculating the representative temperature of the fourth nozzle group.

[0096] <Drive pulse control based on typical temperature> Figure 17 is a flowchart of the drive pulse control process in the fourth embodiment. Specifically, it shows the process of acquiring a representative temperature and drive pulse control based on the representative temperature. Steps S1101 to S1109 in Figure 17 are the same as steps S1101 to S1109 in the first embodiment, so their explanation is omitted.

[0097] In step S1701, the MPU 102 determines whether the nozzle region selected in S1103 includes a nozzle region used for intermediate layer recording. If it includes a nozzle region used for intermediate layer recording, the process proceeds to S1702; otherwise, the process proceeds to S1104.

[0098] In step S1702, the MPU 102 obtains information on the nozzle area to be used for recording, excluding the nozzle used for recording the intermediate layer, from the recording mode. Steps S1703 to S1706 are the same as S1105 to S1108, so their explanation is omitted.

[0099] From the third and fourth representative temperatures derived in this way, the drive pulse conditions to be applied to the third and fourth drive circuits are determined, and the drive pulse control is terminated.

[0100] As described above, according to the fourth embodiment, in a recording mode in which multiple recording layers are formed on a recording medium, the temperature of the nozzle area used for recording the intermediate layer (a layer where a slightly lower image quality is acceptable) is ignored when determining the representative temperature. This makes it possible to determine the representative temperature more easily and to suppress excessive or insufficient ejection volume from the nozzle during surface layer recording with higher accuracy.

[0101] The disclosures herein include the following inkjet recording apparatus and control methods. (Item 1) An inkjet recording device, A recording means, A recording element array in which multiple recording elements, each generating thermal energy for ejecting ink, are arranged in a predetermined direction, A first drive circuit that drives the recording elements of the first group of recording elements included in the aforementioned recording element array, A second drive circuit that drives recording elements of a second recording element group which is included in the aforementioned recording element array and does not overlap with the first recording element group, A first group of temperature sensors for detecting the temperature at multiple locations along the first group of recording elements, A second group of temperature sensors for detecting the temperature at multiple locations along the second group of recording elements, The recording means includes, An acquisition means for acquiring temperature information obtained from the first temperature sensor group and the second temperature sensor group, A determination means for determining the drive pulses to be applied to the first drive circuit and the second drive circuit based on a representative temperature determined based on the temperature information acquired by the acquisition means, Equipped with, The determination means, in a first recording mode in which recording is performed using at least some of the recording elements of the first recording element group and at least some of the recording elements of the second recording element group, A first representative temperature is determined based on one or more first temperature information obtained from one or more temperature sensors in the first temperature sensor group at positions corresponding to the recording element area used by the first recording element group, and a second representative temperature is determined based on one or more second temperature information obtained from one or more temperature sensors in the second temperature sensor group at positions corresponding to the recording element area used by the second recording element group. The drive pulse applied to the first drive circuit is determined based on the first representative temperature, and the drive pulse applied to the second drive circuit is determined based on the second representative temperature. An inkjet recording apparatus characterized by the following features. (Item 2) The determination means, in a second recording mode different from the first recording mode, A common representative temperature is determined based on the temperature information obtained from one or more temperature sensors located at positions corresponding to the recording element area used in the first and second temperature sensor groups. The drive pulses applied to the first drive circuit and the second drive circuit are determined based on the common representative temperature. The inkjet recording apparatus according to item 1, characterized in that it is a feature of the present invention. (Item 3) The recording elements of the first recording element group and the second recording element group are connected to a common flow path. An inkjet recording apparatus according to item 1 or 2, characterized in that it is a recording apparatus according to item 1 or 2. (Item 4) The aforementioned drive pulse is a double pulse consisting of a pre-pulse and a main pulse. The determination means determines the drive pulses to be applied to the first drive circuit and the second drive circuit such that the pulse width of the prepulse constituting the drive pulse when the first representative temperature is the first temperature is longer than the pulse width of the prepulse constituting the drive pulse when the first representative temperature is a second temperature higher than the first temperature. An inkjet recording device according to any one of items 1 to 3, characterized in that... (Item 5) The determination means determines the first representative temperature and the second representative temperature at predetermined time intervals during scanning by the recording means, and determines the drive pulses to be applied to the first drive circuit and the second drive circuit at predetermined time intervals. An inkjet recording device according to any one of items 1 to 4, characterized by the above. (Item 6) The first representative temperature is the average value of one or more first temperature information, and the second representative temperature is the average value of one or more second temperature information. An inkjet recording device according to any one of items 1 to 5, characterized by the above. (Item 7) The first representative temperature is the maximum value of the one or more first temperature information, and the second representative temperature is the maximum value of the one or more second temperature information. An inkjet recording device according to any one of items 1 to 5, characterized by the above. (Item 8) The first representative temperature is the minimum value of the one or more first temperature information items, and the second representative temperature is the minimum value of the one or more second temperature information items. An inkjet recording device according to any one of items 1 to 5, characterized by the above. (Item 9) The determination means adjusts at least one of the drive pulses applied to the first drive circuit and the drive pulse applied to the second drive circuit so that the difference between the drive pulse applied to the first drive circuit and the drive pulse applied to the second drive circuit becomes smaller when the difference between the two is greater than a predetermined value. An inkjet recording apparatus as described in any one of items 1 to 8, characterized by the above. (Item 10) The recording means has a plurality of recording element rows corresponding to inks of different colors, The recording means is A second recording element array in which multiple recording elements, each generating thermal energy for ejecting black ink, are arranged in the predetermined direction, A third drive circuit that drives the recording elements of the third recording element group included in the second recording element array, A fourth drive circuit that drives the recording elements of a fourth recording element group that is included in the second recording element array and does not overlap with the third recording element group, A third group of temperature sensors for detecting the temperature at multiple locations along the third group of recording elements, A fourth group of temperature sensors for detecting the temperature at multiple locations along the fourth group of recording elements, Includes, The determination means, in a third recording mode in which multiple recording layers are formed on a recording medium, A third representative temperature is determined based on one or more third temperature information obtained from one or more temperature sensors at positions corresponding to the recording element area used in the third recording element group, excluding the recording element area used for the black ink, among the third temperature sensor group, and a fourth representative temperature is determined based on one or more fourth temperature information obtained from one or more temperature sensors at positions corresponding to the recording element area used in the fourth recording element group, excluding the recording element area used for the black ink, among the fourth temperature sensor group, The drive pulse to be applied to the third drive circuit is determined based on the third representative temperature, and the drive pulse to be applied to the fourth drive circuit is determined based on the fourth representative temperature. An inkjet recording apparatus according to any one of items 1 to 9, characterized by the above. (Item 11) A control method for an inkjet recording device, The recording means of the inkjet recording apparatus is A recording element array in which multiple recording elements, each generating thermal energy for ejecting ink, are arranged in a predetermined direction, A first drive circuit that drives the recording elements of the first group of recording elements included in the aforementioned recording element array, A second drive circuit that drives recording elements of a second recording element group which is included in the aforementioned recording element array and does not overlap with the first recording element group, A first group of temperature sensors for detecting the temperature at multiple locations along the first group of recording elements, A second group of temperature sensors for detecting the temperature at multiple locations along the second group of recording elements, Includes, The control method described above is An acquisition step for acquiring temperature information obtained from the first temperature sensor group and the second temperature sensor group, A determination step in which a drive pulse to be applied to the first drive circuit and the second drive circuit is determined based on a representative temperature determined based on the temperature information obtained by the acquisition step, Includes, In the determination step, in a first recording mode in which recording is performed using at least some of the recording elements of the first recording element group and at least some of the recording elements of the second recording element group, A first representative temperature is determined based on one or more first temperature information obtained from one or more temperature sensors in the first temperature sensor group at positions corresponding to the recording element area used by the first recording element group, and a second representative temperature is determined based on one or more second temperature information obtained from one or more temperature sensors in the second temperature sensor group at positions corresponding to the recording element area used by the second recording element group. The drive pulse applied to the first drive circuit is determined based on the first representative temperature, and the drive pulse applied to the second drive circuit is determined based on the second representative temperature. A control method characterized by the following:

[0102] (Other examples) The present invention can also be realized by supplying a program that implements one or more of the functions of the above-described embodiments to a system or device via a network or storage medium, and by having one or more processors in the computer of that system or device read and execute the program. It can also be realized by a circuit (e.g., an ASIC) that implements one or more functions.

[0103] The invention is not limited to the embodiments described above, and various modifications and variations are possible without departing from the spirit and scope of the invention. Accordingly, claims are attached to disclose the scope of the invention. [Explanation of symbols]

[0104] 9 Recording head; 44 Temperature sensor; 102 MPU; 111 Head driver; 123 RAM; 125 Control ROM

Claims

1. An inkjet recording device, A recording means, A recording element array in which multiple recording elements, each generating thermal energy for ejecting ink, are arranged in a predetermined direction, A first drive circuit that drives the recording elements of the first group of recording elements included in the aforementioned recording element array, A second drive circuit that drives recording elements of a second recording element group which is included in the aforementioned recording element array and does not overlap with the first recording element group, A first group of temperature sensors for detecting the temperature at multiple locations along the first group of recording elements, A second group of temperature sensors for detecting the temperature at multiple locations along the second group of recording elements, The recording means includes, An acquisition means for acquiring temperature information obtained from the first temperature sensor group and the second temperature sensor group, A determination means for determining the drive pulses to be applied to the first drive circuit and the second drive circuit based on a representative temperature determined based on the temperature information acquired by the acquisition means, Equipped with, The determination means, in a first recording mode in which recording is performed using at least some of the recording elements of the first recording element group and at least some of the recording elements of the second recording element group, A first representative temperature is determined based on one or more first temperature information obtained from one or more temperature sensors in the first temperature sensor group at positions corresponding to the recording element area used by the first recording element group, and a second representative temperature is determined based on one or more second temperature information obtained from one or more temperature sensors in the second temperature sensor group at positions corresponding to the recording element area used by the second recording element group. The drive pulse applied to the first drive circuit is determined based on the first representative temperature, and the drive pulse applied to the second drive circuit is determined based on the second representative temperature. An inkjet recording apparatus characterized by the following features.

2. The determination means, in a second recording mode different from the first recording mode, A common representative temperature is determined based on the temperature information obtained from one or more temperature sensors located at positions corresponding to the recording element area used in the first and second temperature sensor groups. The drive pulses applied to the first drive circuit and the second drive circuit are determined based on the common representative temperature. The inkjet recording apparatus according to feature 1.

3. The recording elements of the first recording element group and the second recording element group are connected to a common flow path. The inkjet recording apparatus according to feature 1.

4. The aforementioned drive pulse is a double pulse consisting of a pre-pulse and a main pulse. The determination means determines the drive pulses to be applied to the first drive circuit and the second drive circuit such that the pulse width of the prepulse constituting the drive pulse when the first representative temperature is the first temperature is longer than the pulse width of the prepulse constituting the drive pulse when the first representative temperature is a second temperature higher than the first temperature. The inkjet recording apparatus according to feature 1.

5. The determination means determines the first representative temperature and the second representative temperature at predetermined time intervals during scanning by the recording means, and determines the drive pulses to be applied to the first drive circuit and the second drive circuit at predetermined time intervals. The inkjet recording apparatus according to feature 1.

6. The first representative temperature is the average value of one or more first temperature information, and the second representative temperature is the average value of one or more second temperature information. The inkjet recording apparatus according to feature 1.

7. The first representative temperature is the maximum value of the one or more first temperature information, and the second representative temperature is the maximum value of the one or more second temperature information. The inkjet recording apparatus according to feature 1.

8. The first representative temperature is the minimum value of the one or more first temperature information items, and the second representative temperature is the minimum value of the one or more second temperature information items. The inkjet recording apparatus according to feature 1.

9. The determination means adjusts at least one of the drive pulses applied to the first drive circuit and the drive pulse applied to the second drive circuit so that the difference between the drive pulse applied to the first drive circuit and the drive pulse applied to the second drive circuit becomes smaller when the difference between the two is greater than a predetermined value. The inkjet recording apparatus according to feature 1.

10. The recording means has a plurality of recording element rows corresponding to inks of different colors, The recording means is A second recording element array in which multiple recording elements, each generating thermal energy for ejecting black ink, are arranged in the predetermined direction, A third drive circuit that drives the recording elements of the third group of recording elements included in the second array of recording elements, A fourth drive circuit that drives the recording elements of a fourth recording element group which is included in the second recording element array and does not overlap with the third recording element group, A third group of temperature sensors for detecting the temperature at multiple locations along the third group of recording elements, A fourth group of temperature sensors for detecting the temperature at multiple locations along the fourth group of recording elements, Includes, The determination means, in a third recording mode in which multiple recording layers are formed on a recording medium, A third representative temperature is determined based on one or more third temperature information obtained from one or more temperature sensors at positions corresponding to the recording element area used in the third recording element group, excluding the recording element area used for the black ink, and a fourth representative temperature is determined based on one or more fourth temperature information obtained from one or more temperature sensors at positions corresponding to the recording element area used in the fourth recording element group, excluding the recording element area used for the black ink, among the fourth temperature sensor group. The drive pulse applied to the third drive circuit is determined based on the third representative temperature, and the drive pulse applied to the fourth drive circuit is determined based on the fourth representative temperature. The inkjet recording apparatus according to feature 1.

11. A control method for an inkjet recording device, The recording means of the inkjet recording apparatus is A recording element array in which multiple recording elements, each generating thermal energy for ejecting ink, are arranged in a predetermined direction, A first drive circuit that drives the recording elements of the first group of recording elements included in the aforementioned recording element array, A second drive circuit that drives recording elements of a second recording element group which is included in the aforementioned recording element array and does not overlap with the first recording element group, A first group of temperature sensors for detecting the temperature at multiple locations along the first group of recording elements, A second group of temperature sensors for detecting the temperature at multiple locations along the second group of recording elements, Includes, The control method described above is An acquisition step for acquiring temperature information obtained from the first temperature sensor group and the second temperature sensor group, A determination step in which a drive pulse to be applied to the first drive circuit and the second drive circuit is determined based on a representative temperature determined based on the temperature information obtained by the acquisition step, Includes, In the determination step, in a first recording mode in which recording is performed using at least some of the recording elements of the first recording element group and at least some of the recording elements of the second recording element group, A first representative temperature is determined based on one or more first temperature information obtained from one or more temperature sensors in the first temperature sensor group at positions corresponding to the recording element area used by the first recording element group, and a second representative temperature is determined based on one or more second temperature information obtained from one or more temperature sensors in the second temperature sensor group at positions corresponding to the recording element area used by the second recording element group. The drive pulse applied to the first drive circuit is determined based on the first representative temperature, and the drive pulse applied to the second drive circuit is determined based on the second representative temperature. A control method characterized by the following:

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