Recording head, method of controlling recording head, and recording device

Abstract

To shorten time required for temperature adjustment control of a recording chip unit.SOLUTION: A recording head includes: a plurality of recording chip units each of which has a recording chip for discharging liquid to a recording medium, a heater installed in correspondence to the recording chip, and temperature measurement means installed in correspondence to the recording chip; and control means which changes a maximum voltage to be applied to the heater of each of the recording chip units according to a temperature change rate representing an amount of temperature change per unit time of each of the recording chip units on the basis of the temperature measured by the temperature measurement means and performs control to make the temperature of each of the recording chip units reach a set target temperature.SELECTED DRAWING: Figure 7

Description

Technical Field

[0001] The present disclosure relates to a recording head, a method for controlling the recording head, and a recording apparatus.

Background Art

[0002] An inkjet recording apparatus performs recording by ejecting a liquid such as ink from ejection ports of a recording chip. In order to maintain print quality, it is required that the ejected liquid be a constant amount. When the liquid thickens, the ejection amount becomes unstable. Since the viscosity of the liquid is highly temperature-dependent, it is effective to keep the temperature of the liquid within a predetermined temperature range when ejecting a constant amount of the liquid. For this purpose, in addition to the liquid, it is required to perform temperature management including members around the liquid that affect the temperature of the liquid. For example, when the predetermined temperature range is around 100°C, when the power is turned on from a state where the power has been off for a long time, the temperature of the object being temperature-controlled may be significantly lower than the predetermined temperature range. In such a case, if the temperature of the object is rapidly increased by using a heater to reach the predetermined temperature range, the heater may be damaged.

[0003] Patent Document 1 discloses a control method in which, when heating an object with a plurality of heaters, in order to protect the heaters, the target temperature is gradually set higher without rapidly increasing the temperature, and when the temperatures of all the plurality of heaters reach the target temperature, the target temperature is changed to the next target temperature.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the technology disclosed in Patent Document 1, the time to reach the target temperature depends on the object to be heated with the slowest temperature rise. The present disclosure aims to shorten the time required for temperature adjustment control of the recording head.

Means for Solving the Problems

[0006] The recording head according to the present disclosure includes a plurality of recording chip units having a recording chip that discharges a liquid onto a recording medium, a heater installed corresponding to the recording chip, and temperature measuring means installed corresponding to the recording chip, and based on the temperature measured by the temperature measuring means, the maximum voltage applied to the heater of each of the plurality of recording chip units is changed according to the temperature change rate, which is the amount of temperature change per unit time of each of the plurality of recording chip units, and control means for performing control to cause the temperature of each of the plurality of recording chip units to reach a set target temperature, and the control means is characterized in that, among the plurality of recording chip units, the maximum voltage applied to the recording chip unit having a temperature change rate smaller than the average value of the temperature change rates of the plurality of recording chip units is made higher than the currently set maximum voltage value.

Advantages of the Invention

[0007] According to the technology of the present disclosure, it is possible to shorten the time required for temperature adjustment control of the recording head.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Mode for Carrying Out the Invention

[0009] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. Note that the following embodiments do not limit the present disclosure, and not all combinations of features described in the embodiments are essential for the solution means of the present disclosure. For the same configuration, the same reference numerals will be used for description. Also, each step (step) in the flowchart is indicated by a symbol starting with "S".

[0010] In the following description of the embodiments, "recording" includes not only the case of forming significant information such as characters and figures, but also the case of widely forming images, patterns, patterns, etc. on the sheet. Further, "ink" (sometimes referred to as "liquid") should be interpreted broadly, and represents a liquid that can be used for forming images, patterns, patterns, etc., processing the sheet, or processing the ink by being applied on the sheet.

[0011] [First Embodiment] Hereinafter, this embodiment will be described with reference to the drawings. FIG. 1 is a schematic configuration diagram showing an example of the configuration of a recording apparatus. The recording apparatus shown in FIG. 1 is a one-pass type that prints an image by a single movement of a recording medium 100. The recording apparatus includes a recording head 101 as a full-line head in which element substrates having ejection ports for ejecting liquid are arranged across the side corresponding to the entire width of the recording medium 100. The recording medium 100 is conveyed in the direction of the arrow by a conveyance unit 102, and printing is performed by the recording head 101. The recording head 101 according to the present disclosure can be implemented in any form and is not limited to the form shown in FIG. 1. In FIG. 1, a recording apparatus equipped with eight recording heads 101Ka, 101Kb, 101Ya, 101Yb, 101Ma, 101Mb, 101Ca, and 101Cb is shown. These eight recording heads 101 are positioned in the liquid ejection apparatus by a reference member.

[0012] Note that, as described above, the recording head 101 of this embodiment is a so-called page-wide type head of a one-pass type having a length corresponding to the width of the recording medium 100 (the size in the direction orthogonal to the conveyance direction of the recording medium 100). However, the present disclosure is also applicable to a so-called serial type liquid ejection head that performs recording while scanning a liquid ejection head with respect to the recording medium 100. Examples of the serial type liquid ejection head include a configuration in which one element substrate for black ink and one element substrate for color ink are each mounted. Another example is a configuration of a liquid ejection head shorter in width than the recording medium 100 in which several element substrates are arranged such that the ejection ports overlap in the ejection port row direction.

[0013] Fig. 2(a) is a plan view of the recording chip unit 20, Fig. 2(b) is a cross-sectional view of the recording chip unit 20, and Fig. 2(c) is a bottom view of the recording chip unit 20. The configuration for controlling the temperature of the liquid in the inkjet recording apparatus will be described with reference to Figs. 2(a) to 2(c). As shown in Figs. 2(a) and 2(b), the recording chip unit 20 includes a temperature measurement unit 21, a heater 22, a heat conductive plate 23, a liquid 24, and a recording chip 25. The temperature measurement unit 21 is an element that measures the temperature of the heater 22. The heater 22 is a heating element for maintaining the temperature of the liquid 24 within a predetermined temperature range. The heat conductive plate 23 is a member that transfers heat from the heater 22 to the liquid 24. When the liquid 24 such as ink is supplied to the recording chip 25 and the recording chip drive circuit (not shown) is driven, the liquid 24 is ejected from the recording chip 25. The liquid ejected from the ejection port 26 of the recording chip 25 adheres to the recording medium. An image is formed on the recording medium by repeatedly ejecting the liquid onto the recording medium a plurality of times.

[0014] In order to maintain print quality, it is required to keep the liquid ejection amount constant. In order to keep the liquid ejection amount constant, it is effective to set the viscosity of the liquid to a predetermined viscosity. In order to set the liquid to a predetermined viscosity, it is necessary to keep the liquid at a predetermined temperature. For this reason, the recording chip unit shown in Fig. 2(b) adopts a configuration for heating the liquid 24 and its peripheral members. The heat generated by the heater 22 heats the liquid 24 via the heat conductive plate 23. Although the heater 22 is shown as one heater in Fig. 2(a), it may include a plurality of heaters. Also, the temperature is measured by the temperature measurement unit 21 via the heat conductive plate 23. When a thermal equilibrium or a state close to it is reached, the temperature measured by the temperature measurement unit 21, the temperature of the heater 22, and the temperature of the liquid 24 have a high correlation. Therefore, the temperature of the heater 22 and the temperature of the liquid 24 can be known from the temperature measured by the temperature measurement unit 21.

[0015] For example, when the temperature of the liquid 24 is at room temperature, consider the control to adjust the temperature of the liquid 24 to 100°C. When performing temperature adjustment control to raise the temperature of the liquid 24 to the final target temperature of 100°C as quickly as possible, a large amount of power is applied to the heater 22, and excessive heat is applied to the heat conductive plate 23. However, since the generated heat is not immediately transmitted to the surrounding components, heat accumulates in the heater 22. As a result, the temperature of the heater 22 rises immediately, but it takes time for the heat to be transmitted to the heat conductive plate 23. Since heat is not transmitted to the temperature measurement unit 21 either, the temperature adjustment control unit 61 (described later in FIG. 6) cannot appropriately know the temperature of the heater 22 from the temperature measured by the temperature measurement unit 21. FIG. 3 shows a graph with the heater temperature on the horizontal axis and the temperature measured by the temperature measurement unit 21 on the vertical axis. It shows that when the voltage applied to the heater 22 is increased, the temperature measured by the temperature measurement unit 21 changes in the direction of the arrow. It shows that as the voltage applied to the heater 22 increases, the difference between the temperature measured by the temperature measurement unit 21 and the heater temperature increases. In order to suppress the increase of the above difference, the heat generated by the heater 22 can be suppressed so that the heat is sufficiently transmitted to the temperature measurement unit 21. However, if the heat generated in the heater 22 is suppressed, the time until the temperature of the liquid 24 reaches the final target temperature becomes longer.

[0016] FIG. 4 is a diagram showing an example of the arrangement of the recording chip units 20 in the recording head. The recording head has a plurality of recording chip units 20. The recording chip unit 20 shown in FIG. 4 represents a part of the recording head, and four recording chip units 20 are drawn in FIG. 4. Component sharing is performed from the viewpoint of reducing the number of components. For example, in the recording head shown in FIG. 4, four recording chip units 20 share the heat conductive plate 42. Therefore, the four recording chip units 20 are in a thermally coupled state. Also, heaters 22 and temperature measurement units 21 are installed corresponding to the four recording chip units 20 respectively. In this embodiment, the number of recording chip units 20 is four, but this is merely an example. If the number of recording chip units 20 is plural, the number is not particularly limited.

[0017] When performing temperature adjustment control for each individual recording chip unit 20, if the time required to reach the final target temperature is long, the temperature difference between the recording chip units 20 will increase because the temperature changes due to individual differences between chips are different. From the perspective of reducing the stress on the heat conduction plate 23 and the interference of the temperature measured by the temperature sensor, it is desirable for the four recording chip units 20 to change at substantially the same temperature.

[0018] In the present embodiment, in order to appropriately measure the temperature by the temperature measurement unit 21 and shorten the time required to reach the final target temperature, instead of performing temperature adjustment control from the current temperature to the final target temperature at once, the target temperature is set step by step. If temperature adjustment control is performed from the current temperature to the final target temperature at once, the temperature cannot be accurately measured as described above. Therefore, by setting the target temperature step by step, the heat generated by the heater 22 until each target temperature is reached can be suppressed, so that the temperature can be appropriately measured by the temperature measurement unit 21. In addition, by making the target temperatures set step by step common among the plurality of recording chip units 20, it is also possible to prevent a temperature difference from occurring between the recording chip units 20. Moreover, in the present embodiment, by increasing the maximum voltage of the recording chip unit 20 with a slow temperature rise, the time required for temperature adjustment control of the recording head is shortened. Details will be described later.

[0019] FIG. 5(a) shows the temperature change of the temperature measurement unit 21 when temperature adjustment control is performed until the final target temperature T0, assuming that the current temperature of the temperature measurement unit 21 is Tc. The temperature adjustment control starts at time 0, indicating that the temperature of the temperature measurement unit 21 gradually rises from the current temperature Tc and reaches the final target temperature T0. Also in the case of FIG. 5(b), the final target temperature is T0. On the way, the temperature of the temperature measurement unit 21 reaches the final target temperature after passing through the target temperatures of T2 and T1. First, T2 with little temperature change from the current temperature Tc of the temperature measurement unit 21 is set as the target temperature. T2 is a temperature difference set within a temperature range having a correlation between the temperature of the heater 22 and the temperature of the temperature measurement unit 21. When the temperature of the temperature measurement unit 21 reaches the target temperature T2, the target temperature is changed to the next target temperature T1. The target temperature T1 is also a temperature difference set within a temperature range having a correlation between the temperature of the heater 22 and the temperature of the temperature measurement unit 21. By determining the target temperature based on the temperature difference set within the temperature range having a correlation between the temperature of the heater 22 and the temperature of the temperature measurement unit 21 in this way, appropriate temperature adjustment control can be performed up to the final target temperature. Here, as an example, two target temperatures T1 and T2 are set, but it is not limited to this. The number of target temperatures set can be arbitrarily set to any value as long as it is one or more.

[0020] FIG. 6 is a block diagram of the temperature adjustment control unit 61 in the recording head. Referring to FIG. 6, the blocks for performing temperature adjustment control in the recording head will be described. Here, the temperature adjustment control for one recording chip unit 20 will be described. Inside the temperature adjustment control unit 61, the microcomputer 60 performs temperature adjustment control. The current temperature 67 is input to the microcomputer 60. A differential signal 63 corresponding to the difference between the current temperature 67 and a target temperature (not shown) set in the microcomputer 60 is output from the microcomputer 60 to the amplifier 64. Also, a maximum voltage regulation signal 70 is output from the microcomputer 60 to the amplifier 64 to regulate the maximum voltage of the amplifier 64. Further, the microcomputer 60 has a mechanism capable of storing various adjustment values in the EEPROM 69 to compensate for the individual differences of the recording chip unit 20. Note that the storage element is not limited to the EEPROM, and a non-volatile memory such as a flash memory may be used. When assembling and adjusting the recording head, various adjustment values are written into the EEPROM 69. The microcomputer 60 reads out various adjustment values from the EEPROM 69 and controls the recording chip unit 20 using the various adjustment values.

[0021] The differential signal 63 is input to the amplifier 64, and the amplifier 64 amplifies the differential signal 63. The amplified signal is output to the heater 22 as the heater voltage 68. At this time, the maximum voltage is regulated by the maximum voltage regulation signal 70 from the microcomputer 60. The heater 22 generates heat due to the heater voltage 68, and the heat is conducted to the temperature measurement unit 21 through a heat conductive plate 23 (not shown in FIG. 6). The temperature measured by the temperature measurement unit 21 is returned as the current temperature 67 to the temperature adjustment control unit 61 as a negative feedback amount. Finally, control is performed so that the target temperature and the current temperature 67 match.

[0022] When the temperature distribution across the entire heat-conductive plate 23 is uniform, the four recording chip units 20 shown in FIG. 4 reach the target temperature without a large time difference. However, the temperature distribution across the entire heat-conductive plate 23 that receives heat from the four heaters 22 may not be uniform and may have non-uniformity. That is, even if the temperatures of the four recording chip units 20 are the same, due to the influence of factors such as the arrangement relationship of the recording chip units, the temperature distribution of the heat-conductive plate 23 around the four recording chip units 20 is different. That is, the temperature of the heat-conductive plate 23 around a certain recording chip unit 20 may be high over a wide range, while the temperature of the heat-conductive plate 23 around another recording chip unit 20 may only be high in a narrow range. Therefore, non-uniformity occurs in the temperature distribution across the entire heat-conductive plate 23. Therefore, until the temperature reaches the target temperature from the current temperature 67, the temperatures of the four recording chip units 20 do not increase at the same temperature gradient. Therefore, there are a recording chip unit 20 that reaches the target temperature quickly and a recording chip unit 20 that reaches the target temperature slowly.

[0023] FIG. 7 is a graph showing the temperature change during temperature adjustment control. Referring to FIG. 7, the above control will be specifically described. When starting the temperature adjustment control to raise the temperature of the temperature measurement unit 21 from the current temperature Tc to the target temperature T2, the temperature of the temperature measurement unit 21 rises toward T2. Ideally, the temperatures of the four recording chip units 20 change at the same temperature change rate, but due to the non-uniformity of the temperature distribution described above, the temperature change rates of the four recording chip units 20 are different. Therefore, the line starting from Tc is divided into four.

[0024] In this embodiment, in order to protect the heater 22, the target temperature is set step by step. Specifically, after the temperature of all the recording chip units 20 reaches T2, the target temperature is changed from T2 to T1. In this way, the target temperature of the temperature measurement unit 21 is changed from T2 to T1 and from T1 to T0, and the temperature of the temperature measurement unit 21 of all the recording chip units 20 becomes the final target temperature T0. The time to reach the final target temperature T0 is determined by the recording chip unit 20 with the smallest temperature change rate in the temperature adjustment control. Therefore, in order to shorten the time to reach the final target temperature T0, the maximum voltage applied to the heater 22 of the recording chip unit 20 with a smaller temperature change rate than the average value of the temperature change rates of the four recording chip units 20 is made higher than the currently set maximum voltage value. When this control is performed, the calorific value of the heater 22 of the recording chip unit 20 with a temperature change rate lower than the average value of the temperature change rates increases, and the temperature change of the recording chip unit 20 is promoted. As a result, it becomes possible to shorten the time for the temperature of the temperature measurement unit 21 to reach the final target temperature T0.

[0025] FIG. 8 is a graph showing the temperature change during the temperature adjustment control according to this embodiment. With reference to FIG. 8, the above temperature adjustment control will be described. The temperature adjustment control for changing the temperature of the temperature measurement unit 21 from the current temperature Tc to the target temperature T2 starts at time tc. Since the temperature distribution of the entire heat conductive plate 23 is non-uniform, there are also individual differences in the temperature changes in the four recording chip units 20. The state of the temperature change due to the individual differences is shown in FIG. 8 using the temperature changes 81 to 84. The recording chip unit 20 indicated by the temperature change 84 is the recording chip unit with the smallest temperature change rate. The recording chip unit 20 indicated by the temperature change 81 is the recording chip unit with the largest temperature change rate.

[0026] When the method shown in FIG. 7 is used, the timing at which the target temperature T2 based on the temperature change 84 with the smallest temperature change rate is reached becomes the timing t84 at which the temperature adjustment control for the entire recording chip unit 20 is completed. In the present embodiment, information on the temperature change rate of the recording chip unit 20 is input to the temperature adjustment control unit 61, and the maximum voltage of the amplifier 64 is changed based on the temperature change rate. Specifically, the maximum voltage applied to the heater 22 of the recording chip unit 20 with a small temperature change rate is set to a value higher than the currently set maximum voltage value, and the temperature change of the recording chip unit is promoted.

[0027] Since the maximum voltage applied to the heater 22 of the recording chip unit 20 indicated by the temperature change 84, which has a small temperature change rate, becomes higher than the currently set maximum voltage value, the amount of heat generated by the heater 22 becomes larger than before increasing the maximum voltage value applied to the heater 22. As a result, the temperature change of the recording chip unit 20 approaches the temperature change 83 (see FIG. 8). By performing the above temperature adjustment control, the control time for temperature adjustment of the recording chip unit 20 with the smallest temperature change rate is shortened, and as shown in FIG. 8, the time at which the temperature adjustment control as the recording head is completed is shortened by only tb1.

[0028] Figure 9 is a flowchart of temperature adjustment control. Referring to the flowchart of Figure 9, the flow of the above temperature adjustment control method will be described. In S901, the temperature adjustment control unit 61 sets the maximum voltage applied to the recording chip unit 20 with a smaller temperature change rate than the average value of the temperature change rates of the plurality of recording chip units 20 to a value higher than the currently set maximum voltage value, and the process proceeds to S902. In S902, the temperature adjustment control unit 61 outputs the maximum voltage to the heater 22 of the recording chip unit 20 so that the temperature measured by the temperature measurement unit 21 becomes the target temperature, and the process proceeds to S903. In S903, the temperature adjustment control unit 61 checks whether all the recording chip units 20 have reached the target temperature. If not all the recording chip units 20 sharing the heat conductive plate 23 have reached the target temperature, the process returns to S902. If all the recording chip units 20 sharing the heat conductive plate 23 have reached the target temperature, the processing flow of the flowchart shown in Figure 9 ends.

[0029] Next, a specific method for obtaining the temperature change rate of the recording chip unit 20 will be described. This is a method of measuring the temperature change of the recording chip unit 20 with respect to time during temperature adjustment control by utilizing the fact that the current temperature 67 of the temperature measurement unit 21 is input to the microcomputer 60 in the temperature adjustment control unit 61. Specifically, the temperature change amount of the recording chip unit 20 within a predetermined time, or the temperature change amount of the recording chip unit 20 during the time from the temperature Tc to T2 is obtained. Based on the obtained temperature change amount and time, the microcomputer 60 calculates the temperature change rate of the recording chip unit 20, which is the temperature change amount per unit time, and uses this temperature change rate for the above temperature adjustment control. It is also possible to store the temperature change rate of the recording chip unit 20 in the EEPROM 69 built in the temperature adjustment control unit 61 and read out and use the temperature change rate during the next temperature adjustment control.

[0030] As an alternative method, the following method may be used. When assembling and adjusting the recording head, the maximum voltage before temperature adjustment control is applied to each recording chip unit 20, and the temperature change rate of each recording chip unit 20 is measured for each temperature. The temperature change rate of each recording chip unit 20 measured for each measured temperature is stored in the EEPROM 69 in the temperature adjustment control unit 61 in a table format. The microcomputer 60 reads out the temperature change rate of each recording chip unit 20 stored in the EEPROM 69 based on the current temperature 67, and performs temperature adjustment control on each recording chip unit 20.

[0031] As shown in FIG. 7, when the target temperature is changed stepwise from T2 to T1 and from T1 to T0 and the control according to this embodiment is performed, the time required for temperature adjustment control of the recording head in each section can be shortened. Therefore, when the temperature of the temperature measurement unit 21 is changed to Tc → T2 → T1 → T0, it is possible to shorten the time required for temperature adjustment control. As described above, according to the technology of this embodiment, it is possible to shorten the time required for temperature adjustment control of the recording head.

[0032] [Second Embodiment] In the first embodiment, the control for shortening the time required for temperature adjustment control of the recording head was described. However, when the temperature adjustment control of the first embodiment is performed, the power consumption of the entire recording chip unit 20 increases. A method for suppressing the power consumption of the entire recording chip unit 20 will be described in the second embodiment. FIG. 10 is a graph showing the temperature change during temperature adjustment control according to this embodiment. The horizontal axis represents the elapsed time, and the vertical axis represents the measured temperature of the temperature measurement unit 21. It shows the state of reaching the final target temperature T0 through two target temperatures T2 and T1 from the current temperature Tc at time zero.

[0033] In section A of FIG. 10, temperature adjustment control is performed from the current temperature Tc to the target temperature T2 using the method shown in FIG. 7, and the temperature adjustment control unit 61 acquires the temperature change rate of each recording chip unit 20. Using the method described in the first embodiment, the temperature adjustment control unit 61 calculates the temperature change rate of each recording chip unit 20.

[0034] Next, in section B of FIG. 10, the maximum voltage applied to the heater 22 of each recording chip unit 20 is changed based on the temperature change rate obtained in the immediately preceding section A. That is, for a recording chip unit 20 whose temperature change rate is smaller than the average value, in order to shorten the control time for temperature adjustment, the maximum voltage applied to the heater 22 of the recording chip unit 20 is made higher than the currently set maximum voltage value. On the other hand, for a recording chip unit 20 whose temperature change rate is larger than the average value, the maximum voltage applied to the heater 22 of the recording chip unit 20 is made lower than the currently set maximum voltage value, and the temperature change of the recording chip unit 20 is moderated. When such control is performed, ideally, the temperatures of the temperature measurement units 21 of all the recording chip units 20 reach the target temperature simultaneously.

[0035] In the above, the determination of the recording chip unit 20 with a large or small temperature change rate was made based on the average value of the temperature change rate. As an alternative method, in order to perform a simple determination, the recording chip unit 20 with the largest temperature change rate may be regarded as having a large temperature change, and the recording chip unit 20 with the smallest temperature change rate may be regarded as having a small temperature change.

[0036] As described above, the voltage applied to the heater 22 of each recording chip unit 20 is set, and temperature adjustment control with the target temperature set to T1 is performed. Since the temperature change of the recording chip unit 20 with the smallest temperature change rate is promoted, the completion time of the temperature adjustment control is shortened. Therefore, the completion time of the temperature adjustment control for the entire recording head is also shortened. In section B of FIG. 10, the time tb2 corresponds to the amount of time shortening. The power supplied to the heater 22 of the recording chip unit 20 whose temperature change rate is smaller than the average value increases. On the other hand, the power supplied to the heater 22 of the recording chip unit 20 whose temperature change rate is larger than the average value decreases. Therefore, compared with the case where the control shown in FIG. 7 is performed, there is no significant difference in the power consumption of the entire recording head. Therefore, the power consumption of the entire recording head in the present embodiment is suppressed compared to the power consumption of the first embodiment.

[0037] In the section of section B in FIG. 10, temperature adjustment control is performed and at the same time, the temperature change rate is measured or read out. Since the temperature change rate varies depending on the measured temperature range, it is preferable to update the maximum voltage applied to the heater 22 based on the temperature change rate in section B. As an alternative, it is also possible to continuously use the temperature change rate measured in section A of FIG. 10.

[0038] Subsequently, in section C of FIG. 10, the target temperature is changed from T1 to the final target temperature T0, and by performing the same control as in section B of FIG. 10, the time until the temperature adjustment control is completed when reaching the final target temperature T0 is shortened by time tc2. When compared with the case where the control shown in FIG. 7 is performed, there is no significant difference in the overall power consumption of the recording head in section C of FIG. 10 compared to section B of FIG. 10.

[0039] As described above, in this embodiment, the control time required for temperature adjustment of the recording head is shortened by tb2 + tc2, and there is no significant difference in the overall power consumption of the recording head compared to the case where this embodiment is not implemented (see FIG. 7). The technology of this embodiment also makes it possible to shorten the time required for temperature adjustment control of the recording head.

[0040] The disclosure of the above-described embodiment includes the following configurations.

[0041] (Configuration 1) A recording head comprising: a plurality of recording chip units each having a recording chip for discharging a liquid onto a recording medium, a heater installed corresponding to the recording chip, and temperature measuring means installed corresponding to the recording chip; and control means for changing the maximum voltage applied to the heater of each of the plurality of recording chip units according to the temperature change rate which is the amount of temperature change per unit time of each of the plurality of recording chip units based on the temperature measured by the temperature measuring means, and performing control to cause the temperature of each of the plurality of recording chip units to reach a set target temperature, wherein the control means increases the maximum voltage applied to the recording chip unit having a temperature change rate smaller than the average value of the temperature change rates of the plurality of recording chip units among the plurality of recording chip units to be higher than the currently set maximum voltage value.

[0042] (Configuration 2) The recording head according to Configuration 1, wherein the control means decreases the maximum voltage applied to the recording chip unit having a temperature change rate larger than the average value of the temperature change rates of the plurality of recording chip units to be lower than the currently set maximum voltage value.

[0043] (Configuration 3) The recording head according to Configuration 1, wherein the control means changes the maximum voltage applied to the heater corresponding to each of the plurality of recording chip units based on the temperature change rate of each of the plurality of recording chip units obtained when performing control to reach the immediately preceding target temperature.

[0044] (Configuration 4) The recording head according to Configuration 1, further comprising storage means for storing the temperature change rate of each of the plurality of recording chip units for each temperature when the maximum voltage before performing temperature adjustment control is applied to each of the plurality of recording chip units, and the control means reads the temperature change rate of each of the plurality of recording chip units stored in the storage means based on the measured temperature, thereby changing the maximum voltage applied to the heater corresponding to each of the plurality of recording chip units.

[0045] (Configuration 5) The recording head according to Configuration 1, wherein each of the plurality of recording chip units is disposed between the heater and the recording chip, and further includes a heat conductive plate that transfers heat from the heater to the recording chip.

[0046] (Configuration 6) The recording head according to Configuration 5, wherein the plurality of recording chip units share the heat conductive plate.

[0047] (Configuration 7) A recording apparatus including the recording head according to any one of Configurations 1 to 6.

[0048] (Configuration 8) A method for controlling a recording head, the recording head including a plurality of recording chip units each having a recording chip that discharges a liquid onto a recording medium, a heater installed corresponding to the recording chip, and a temperature measuring means installed corresponding to the recording chip, the method including: changing a maximum voltage applied to the heater of each of the plurality of recording chip units according to a temperature change rate which is a temperature change amount per unit time of each of the plurality of recording chip units, based on the temperature measured by the temperature measuring means; and causing the temperature of each of the plurality of recording chip units to reach a set target temperature, wherein, among the plurality of recording chip units, the maximum voltage applied to the recording chip unit having a temperature change rate smaller than an average value of the temperature change rates of the plurality of recording chip units is made higher than a currently set maximum voltage value.

[0049] (Configuration 9) A recording head including: a plurality of recording chip units each having a recording chip that discharges a liquid onto a recording medium, a heater installed corresponding to the recording chip, and a temperature measuring means installed corresponding to the recording chip; and control means for changing a maximum voltage applied to the heater of each of the plurality of recording chip units according to a temperature change rate which is a temperature change amount per unit time of each of the plurality of recording chip units, based on the temperature measured by the temperature measuring means, and for controlling to cause the temperature of each of the plurality of recording chip units to reach a set target temperature simultaneously.

[0050] A method for controlling a recording head, wherein the recording head includes a plurality of recording chip units each having a recording chip that discharges a liquid onto a recording medium, a heater installed corresponding to the recording chip, and a temperature measuring means installed corresponding to the recording chip, and based on the temperature measured by the temperature measuring means, changing a maximum voltage applied to the heater of each of the plurality of recording chip units according to a temperature change rate which is a temperature change amount per unit time of each of the plurality of recording chip units, and a step of simultaneously causing the temperatures of each of the plurality of recording chip units to reach a set target temperature. A method for controlling a recording head, characterized by comprising these steps.

Claims

1. A recording chip that discharges liquid onto a recording medium, A heater installed corresponding to the recording chip, Temperature measuring means installed corresponding to the recording chip, A plurality of recording chip units having the above, Based on the temperature measured by the temperature measuring means, the maximum voltage applied to the heater of each of the plurality of recording chip units is changed according to the temperature change rate, which is the amount of temperature change per unit time of each of the plurality of recording chip units, and control is performed to cause the temperature of each of the plurality of recording chip units to reach a set target temperature. Control means, comprising, The control means increases the maximum voltage applied to the recording chip unit having a temperature change rate smaller than the average value of the temperature change rates of the plurality of recording chip units among the plurality of recording chip units to be higher than the currently set maximum voltage value. A recording head characterized by that.

2. The control means lowers the maximum voltage applied to the recording chip unit having a temperature change rate larger than the average value of the temperature change rates of the plurality of recording chip units among the plurality of recording chip units to be lower than the currently set maximum voltage value. The recording head according to claim 1.

3. The control means changes the maximum voltage applied to the heater corresponding to each of the plurality of recording chip units based on the temperature change rate of each of the plurality of recording chip units obtained when performing control to reach the immediately previous target temperature. The recording head according to claim 1.

4. Further comprising storage means for storing the temperature change rate of each of the plurality of recording chip units for each temperature when the maximum voltage before performing temperature adjustment control is applied to each of the plurality of recording chip units, The control means reads the temperature change rate of each of the plurality of recording chip units stored in the storage means based on the measured temperature, thereby changing the maximum voltage applied to the heater corresponding to each of the plurality of recording chip units. The recording head according to claim 1.

5. The recording head according to claim 1, wherein each of the plurality of recording chip units is disposed between the heater and the recording chip, and further includes a heat conductive plate for transferring heat from the heater to the recording chip.

6. The recording head according to claim 5, wherein the plurality of recording chip units share the heat conductive plate.

7. A recording apparatus comprising the recording head according to any one of claims 1 to 6.

8. A method for controlling a recording head, comprising: The recording head includes: a recording chip for discharging a liquid onto a recording medium; a heater installed corresponding to the recording chip; temperature measuring means installed corresponding to the recording chip; and a plurality of recording chip units having the same, changing a maximum voltage applied to the heater of each of the plurality of recording chip units according to a temperature change rate, which is a temperature change amount per unit time of each of the plurality of recording chip units, based on the temperature measured by the temperature measuring means; causing the temperature of each of the plurality of recording chip units to reach a set target temperature; and having Among the plurality of recording chip units, the maximum voltage applied to the recording chip unit having a temperature change rate smaller than the average value of the temperature change rates of the plurality of recording chip units is made higher than the currently set maximum voltage value. A method for controlling a recording head, characterized in that.

9. a recording chip for discharging a liquid onto a recording medium; a heater installed corresponding to the recording chip; temperature measuring means installed corresponding to the recording chip; and a plurality of recording chip units having the same, Based on the temperature measured by the temperature measuring means, the maximum voltage applied to the heater of each of the plurality of recording chip units is changed according to the temperature change rate, which is the amount of temperature change per unit time of each of the plurality of recording chip units, and control is performed to cause the temperatures of each of the plurality of recording chip units to reach a set target temperature simultaneously. A recording head, characterized by comprising

10. A method for controlling a recording head, wherein the recording head comprises a recording chip that discharges a liquid onto a recording medium, a heater installed corresponding to the recording chip, a temperature measuring means installed corresponding to the recording chip, and a plurality of recording chip units having the above, Based on the temperature measured by the temperature measuring means, a step of changing the maximum voltage applied to the heater of each of the plurality of recording chip units according to the temperature change rate, which is the amount of temperature change per unit time of each of the plurality of recording chip units, a step of causing the temperatures of each of the plurality of recording chip units to reach a set target temperature simultaneously, and a method for controlling a recording head, characterized by comprising the above.

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