Recording device and method for determining temperature

Abstract

To determine representative temperature of a recording element that is used for recording.SOLUTION: A recording device determines representative temperature on the basis of information output from a plurality of temperature detection elements installed to a recording head and a positional relationship between recording elements used for recording operation immediately thereafter.SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] The present invention relates to a recording device and a method for determining a temperature. [Background technology]

[0002] The ink in an inkjet recording device changes its physical properties, such as viscosity and surface tension, depending on the temperature, and the amount of ink ejected differs depending on whether the temperature of the ink near the recording element when the ink is ejected is high or low, which can result in a decrease in image quality. For this reason, it is necessary to acquire the ink temperature.

[0003] Patent Document 1 discloses a method for determining a representative temperature of a recording element substrate by providing a plurality of temperature sensors at different positions in the arrangement direction on the recording element substrate and taking a weighted average based on a plurality of temperatures detected by the plurality of temperature sensors. Patent Document 2 discloses a method for determining the higher temperature as the representative temperature when each of a plurality of temperatures detected by a plurality of temperature sensors is higher than a predetermined threshold, and determining the lower temperature as the representative temperature when each of the temperatures is lower than the predetermined threshold. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2013-99922 A [Patent Document 2] JP 2016-43636 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the methods disclosed in Patent Documents 1 and 2, depending on the driving state of the printing element array, it may be impossible to select an appropriate temperature as the representative temperature.

[0006] For example, in the method of Patent Document 2, when a representative temperature is determined when each of the multiple temperatures is higher than a predetermined threshold and there is a large temperature difference in the print element array, the highest temperature is selected. However, in subsequent printing, the print element near the temperature sensor that showed the highest temperature is not necessarily driven.

[0007] The present invention has been made in consideration of the above-mentioned problems, and has an object to determine a representative temperature of a printing element used for printing. [Means for solving the problem]

[0008] The present invention comprises a printing element array in which a plurality of printing elements that generate energy for ejecting droplets are arranged in a predetermined direction, a printing head having a plurality of temperature detection elements arranged at different positions in the predetermined direction, and a determination means for determining a representative temperature of the printing head based on information output from each of the plurality of temperature detection elements, wherein the determination means determines the representative temperature based on the information output by the plurality of temperature detection elements and the positional relationship of the printing elements to be used in the immediately following printing operation. Effect of the Invention

[0009] According to the present invention, it is possible to determine the representative temperature of the recording element used for recording. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic diagram of a printing apparatus according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a schematic diagram showing the configuration of a recording head according to the present embodiment. [Diagram 3] FIG. 2 is a block diagram showing the overall control configuration of the printing apparatus according to the present embodiment. [Figure 4] 5 is a block diagram showing a process flow in a head temperature control circuit in the embodiment. FIG. [Diagram 5] 5 is a flowchart showing a flow of print control in the first embodiment. [Figure 6] 5 is a diagram showing the correspondence between print data, print nozzles, and nozzle usage modes in the first embodiment. FIG. [Figure 7] 4 is a flowchart showing a representative temperature determination process in the first embodiment. [Figure 8] 10A to 10C are diagrams showing the correspondence between print data, print nozzles, nozzle usage modes, and temperature distribution within the print nozzles under conditions in which the first embodiment is effective. [Figure 9] 10 is a flowchart showing a flow of print control in the second and third embodiments. [Figure 10] 10 is a flowchart showing a nozzle drive data calculation and storage process in the second and third embodiments. [Figure 11] 13A to 13C are diagrams illustrating a method of calculating nozzle drive data in the second and third embodiments. [Figure 12] 10 is a flowchart showing a representative temperature determination process in the second embodiment. [Figure 13] 13 is a flowchart showing a representative temperature determination process in the third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0012] <Basic configuration of an inkjet recording device (Figs. 1 to 4)> FIG. 1 is a perspective view partially showing the internal configuration of a recording device 100 which is a representative embodiment of the present invention. As shown in FIG. 1, the recording device 100 includes a paper feed unit 101, a transport unit 102, a recording unit 103, and a recovery unit 104. The paper feed unit 101 supplies a recording medium into the device body. The transport unit 102 transports the recording medium supplied by the paper feed unit 101 in the Y direction (transport direction). The recording unit 103 records an image on the recording medium based on image information. The recovery unit 104 performs a recovery operation to maintain the ink ejection performance of the recording head in order to maintain the quality of the recorded image.

[0013] A paper feed unit 101 feeds recording media into the main body of the apparatus. The recording media loaded on the paper feed unit 101 are picked up one by one by a pickup roller and a paper feed roller (not shown) driven by a paper feed motor (not shown), and are fed to a conveyance unit 102. A recording medium end detection sensor (not shown) is located upstream of the conveyance roller 105, and when the leading edge of the recording medium passes the sensor, the passing can be detected.

[0014] The conveying unit 102 conveys the recording medium supplied by the paper supply unit 101. The recording medium fed to the conveying unit 102 is sandwiched between a conveying roller 105 driven by a conveying motor (not shown) and a pinch roller (not shown), and conveyed through the recording unit 103.

[0015] The recording unit 103 records an image by ejecting droplets (ink in this embodiment) from a recording head 107 (described later) onto a recording medium based on image data. The recording unit 103 includes a carriage 106 capable of reciprocating in an X direction (scanning direction) intersecting with a Y direction, and recording heads 107 and 108 (described later) mounted on the carriage 106.

[0016] The carriage 106 is supported so as to be capable of reciprocating in the X direction along a guide rail installed in the recording device. The carriage 106 reciprocates in the recording area via a carriage belt 109 driven by a carriage motor (not shown) when recording on the recording medium. The position and speed of the carriage 106 are detected by an encoder sensor (not shown) mounted on the carriage 106 and an encoder scale 110 stretched across the recording device, and the movement of the carriage 106 is controlled based on these position and speed. While the carriage 106 is moving, recording is performed on the recording medium by ejecting ink from the recording heads 107 and 108 of the recording unit 103. The recording medium is sandwiched between a discharge roller (not shown) driven synchronously with the conveying roller 105 by the conveying unit 102, and a spur (not shown) pressed against the discharge roller, and is discharged outside the recording device. At this time, a recording medium end detection sensor (not shown) can detect the passage of the trailing end of the recording medium when the trailing end of the recording medium passes the sensor.

[0017] The recovery unit 104 includes a wiping mechanism, a capping mechanism, and a suction mechanism. The wiping mechanism wipes off ink droplets adhering to the surface (ejection port surface) on which the ejection ports of the recording heads 107 and 108 are provided, thereby recovering the state of the ejection port surface to a normal state. The capping mechanism covers the ejection ports. The suction mechanism sucks ink from the ejection ports using the capping mechanism.

[0018] FIG. 2 is a schematic diagram showing the configuration of the print head 107 of this embodiment. The print head 107 (hereinafter also referred to as a color head) is a color head that ejects cyan ink, magenta ink, and yellow ink, and the print head 108 (hereinafter also referred to as a black head) is a black head that ejects black ink. FIG. 2(a) is a perspective view showing the print head 107. The perspective view of the print head 108 is omitted because it is generally similar to the perspective view of the print head 107. FIG. 2(b-1) is a bottom view of the print head 107 as viewed in the Z direction. Also, FIG. 2(b-2) is a bottom view of the print head 108 as viewed in the Z direction. FIG. 2(c-1) is an enlarged view showing a cyan ink ejection port array 205 of the print head 107. The enlarged views of the magenta ink ejection port array 206 and the yellow ink ejection port array 207 are omitted because they are similar to the enlarged view of the cyan ink ejection port array. FIG. 2C is an enlarged view showing the ejection port array 211 for black ink of the print head 108. FIG.

[0019] The printhead 107 receives print signals from the printing apparatus body via contact pads 201, and is supplied with power required to drive the printhead. The print chip 202 is provided with a main diode sensor 203 and a sub-diode sensor 204 as temperature detection elements for detecting the temperature of the printhead substrate. The print chip 202 is also provided with an ejection port array 205 for ejecting cyan ink, an ejection port array 206 for ejecting magenta ink, and an ejection port array 207 for ejecting yellow ink. The print chip 202 is also provided with a sub-heater 208 for heating ink, which is arranged to surround the ejection port arrays 205, 206, and 207. This sub-heater heats or does not heat the printhead substrate and ink depending on whether a voltage is applied. On both sides of the ink liquid chamber 218, ejection ports (nozzles) 213 for ejecting 5pl of ink are arranged, and directly below (on the +Z direction side) of each ejection port, a heater 214 for ejecting 5pl of ink is arranged. The number of the ejection ports 213 is 768, and the interval between the ejection ports is 1 / 1200 inch. Therefore, the print head 107 of this embodiment is configured so that the print pixel density is 1200 dpi.

[0020] The printhead 108 receives print signals from the printing apparatus body via contact pads, and is supplied with power required to drive the printhead, in the same manner as the printhead 107. The print chip of the printhead 108 is provided with a main diode sensor 209 for detecting the temperature of the printhead substrate, a sub-diode sensor 210, and an ejection port array 211 for ejecting black ink. In addition, sub-heaters 212 for heating ink are provided, which are arranged to sandwich the ejection port array 211. The sub-heaters heat or do not heat the printhead substrate and ink depending on whether or not a voltage is applied. On both sides of the ink liquid chamber 215, ejection ports 216 for ejecting 9pl of ink are arranged, and directly below each ejection port (on the +Z direction side), a heater 217 for ejecting ink of 9pl is arranged. The number of the ejection ports 216 is 832, and the interval between the ejection ports is 1 / 1200 inch. Thus, the printhead 108 of this embodiment is configured to have a print pixel density of 1200 dpi.

[0021] The ink ejection heaters 214 and 217 can keep the ink warm by applying a drive pulse that is not strong enough to eject ink. Hereinafter, this type of heat-retention control will be referred to as short-pulse heating control. The printing apparatus of this embodiment adjusts the temperature of the printhead substrate and the ink temperature (hereinafter collectively referred to as head temperature) by short-pulse heating control and sub-heater control.

[0022] The printing apparatus of this embodiment adjusts the head temperature by sub-heater and short pulse heating control, and performs feedback control by switching between heating and non-heating the printhead substrate so as to approach the target temperature based on the output value of the main diode sensor 203. Similarly, feedback control is performed for the printhead 108 by switching between heating and non-heating the printhead substrate so as to approach the target temperature based on the output value of the main diode sensor 209.

[0023] In the printing apparatus of this embodiment, while the carriage 106 is moving, printing is performed on the printing medium by ejecting ink from the print heads 107 and 108 of the printing unit 103. Ink is ejected by applying an ejection drive pulse to ink ejection heaters 214 and 217, which are printing elements that generate energy. The drive pulse is modulated so as to keep the ejection amount constant, based on the head temperature output from the main diode sensors 203 and 209 and the sub diode sensors 204 and 210. The head temperature used to modulate the drive pulse is preferably obtained at a timing when the ejection heaters are not driven, in order to reduce the influence of noise.

[0024] 3 is a block diagram showing the overall control configuration of the printing apparatus of this embodiment. The components of this control configuration can be roughly divided into hardware processing means and software control means. The hardware processing means includes processing means such as an operation unit 308, a recovery operation control circuit 309, a head temperature control circuit 314, a head drive control circuit 316, a carriage drive control circuit 306, and a transport control circuit 307, each of which accesses the main bus line 305. The software control means includes processing means such as an image input unit 303, each of which accesses the main bus line 305, an image signal processing unit 304 corresponding thereto, a drive and print element position storage unit 317 that stores the print element to be used in the immediately following print operation based on the processed image signal, a representative temperature determination unit 318 that determines a representative temperature for each print head based on head temperature information from the diode sensors 203, 204, 209, and 210 acquired by the head temperature control circuit 314, and a control unit CPU 300. The CPU 300 normally has a ROM 301 and a RAM 302, and provides appropriate printing conditions for input information, and drives the ink ejection heaters 214 and 217 in the printheads 107 and 108 to perform printing. The ROM 301 also stores a program for executing a printhead recovery timing chart, and provides recovery conditions such as preliminary ejection conditions to a recovery operation control circuit 309 and the printheads 107 and 108 as necessary. A recovery motor 310 drives the printheads 107 and 108, a wiping blade 311 opposed to and spaced from the printheads, a cap 312, and a suction pump 313. A head temperature control circuit 314 determines the driving conditions for the sub-heaters 208 and 212 on the printheads 107 and 108 based on the output values ​​of a thermistor 315 that detects the environmental temperature, which is the temperature around the printhead, and the main diode sensors 203 and 209 that detect the printhead temperature. Then, the head drive control circuit 316 drives the sub-heaters 208, 212 based on the determined drive conditions. The head drive control circuit 316 also drives the ink ejection heaters 214, 217 on the print heads 107, 108. Driving the ink ejection heaters 214, 217 causes the print heads 107, 108 to perform preliminary ejection, ink ejection, and ink temperature adjustment for temperature control.A program for executing the temperature adjustment control is stored in, for example, ROM 301, and executes detection of the printhead temperature and driving of the sub-heater 208 via a head temperature control circuit 314 and a head drive control circuit 316. The head drive control circuit 316 can perform the above-mentioned drive pulse modulation control by driving the ink ejection heaters 214, 217 with a drive signal consisting of a pre-pulse and a main pulse. The drive element information may be stored in the drive print element position storage unit 317 collectively for all print scans before the start of printing, or only the information corresponding to each print scan may be stored before the execution of that print scan.

[0025] 4 is a block diagram showing the flow of processing in the head temperature control circuit 314 and processing performed on the software through the ROM 301 / RAM 302. When a voltage based on the printhead temperature is input from the main diode sensors 203 and 209 provided on the printheads 107 and 108 to the head temperature control circuit 314, the voltage value is amplified by an amplifier 401. The amplified voltage value is then digitized by an AD converter 402. The digitized diode sensor voltage value ADMain is converted to a main diode temperature TMain by an ADMain-temperature conversion formula 403 stored in the ROM 301. On the other hand, when a voltage based on the printhead temperature is input from the sub-diode sensors 204 and 210 to the head temperature control circuit 314, the voltage is digitized by an AD converter 404. The digitized sub-diode voltage value ADSUB is converted to a sub-diode temperature TSub by an ADSub-temperature conversion formula 405 in the ROM 301. The main diode temperature and the sub-diode temperature obtained as described above are input to a head temperature detection unit 406 and used for control of this embodiment. In order to accurately control the head temperature using the sub-heater or short pulse heating, and to precisely modulate the heater drive pulse based on the head temperature, it is more preferable to correct the output temperatures of the main diode sensor and the sub-diode sensor.

[0026] <First embodiment (FIGS. 5 to 8, Table 1)> A first embodiment of the present invention will be described below with reference to the basic configuration of the recording apparatus described above.

[0027] FIG. 6 shows the correspondence between print data, print nozzles, and nozzle use modes. If the number of print elements driven simultaneously increases, there is a concern that the head temperature rise associated with ink ejection will become intense, and power consumption will increase. For this reason, in order to suppress the head temperature rise and power consumption, monitor control may be adopted in which the print operation is divided into multiple times and performed when the number of nozzles used in the print operation exceeds a predetermined threshold. In this embodiment, when the image signal processing unit 304 determines that the total number of ejected dots in the immediately following print scan exceeds a predetermined threshold, monitor control is activated. When monitor control is activated, the print data is divided into two in the print element array direction (predetermined direction) to perform printing in two print scans. The first divided print scan drives the print elements on the sub-diode sensor 210 side, and the second divided print scan drives the print elements on the main diode sensor 209 side. In this embodiment, driven nozzle information is acquired in a pseudo manner by storing and acquiring in the drive printing element position memory unit 317 whether the immediately following printing scan is the first division (Mode 1), the second division (Mode 2), or no division (Mode 3).

[0028] FIG. 5 is a flowchart showing an update process of the drive pulse applied to the ink ejection heater 214 of the printhead 107 and the drive pulse applied to the ink ejection heater 217 of the printhead 108 during a printing operation.

[0029] When the image input unit 303 receives a print command, the printing operation shown in S501 is started. In S502, the output temperatures of the diode sensors 203, 204, 209, and 210 provided on the color head and black head, respectively, are input to the head temperature control circuit 314, and the head temperature converted and calculated according to the process shown in Fig. 4 is obtained. After that, in S503, position information of the printing elements (hereinafter also referred to as nozzles) to be used in the immediately following print scan, which is stored in the drive printing element position memory unit 317, is obtained.

[0030] In the next S504, the representative temperature determination unit 318 determines a representative temperature to be used for determining when modulating the driving pulse of the color head in the immediately following print scan, based on the temperature detected by each diode sensor of the color head obtained in S502 and the driving nozzle information of the immediately following print scan obtained in S503. In S505, the driving pulse of the color head in the immediately following print scan is determined based on the representative temperature determined in S504. In S506 and S507, the same processing as that performed for the color head in S504 and S505 is applied to the black head. Here, it is sufficient that S505 is performed after S504, and S507 is performed after S506. The order of determining the color head representative temperature in S504 and determining the black head representative temperature in S506 may be reversed, or S504 and S506 may be performed together first, and then S505 and S507 may be performed.

[0031] After the drive pulses for the color heads and black heads have been determined, the print scan is started in S508. The print scan is performed by driving each ink ejection heater to eject ink while moving the carriage in a scanning manner, thereby printing an image. After the print scan is completed in S509, it is confirmed in S510 whether the printing of the page has been completed, and if the page needs to be printed, the process returns to S502. If it is confirmed in S510 that the printing of the page has been completed, the process proceeds to S511, where printing is completed and the print medium is discharged.

[0032] 7 is a flowchart showing the representative temperature determination process shown in S504 and S506 in the representative temperature determination unit 318 when determining the head representative temperature used to determine heater drive pulse modulation based on the head detected temperature and the nozzle information used in the immediately following print scan. This flow is executed for the color heads in S504 and for the black head in S506, but the contents are similar. In FIG. 7, the black head will be explained as a representative example.

[0033] When the representative temperature determination process is started in S701, the process transitions to S702, and the drive recording element position storage unit 317 acquires which mode the nozzles to be used in the immediately following recording operation are in. As described above, in this embodiment, the nozzle usage is classified into three types of modes. The first mode (Mode 1) is the nozzle usage mode for the first division when divided printing is initiated, that is, the mode in which the driven nozzles are omnipresent on the sub-diode sensor 210 side. The second mode (Mode 2) is the nozzle usage mode for the second division when divided printing is initiated, that is, the mode in which the driven nozzles are omnipresent on the main diode sensor 209 side. The third mode (Mode 3) is the nozzle usage mode when divided printing is not performed, that is, the mode in which the driven nozzles can be omnipresent on both the main diode sensor 209 side and the sub-diode sensor 210 side. In S703, a conditional branch is performed based on the acquired mode. In the case of the first mode, the process transitions to S704, and the temperature detected by the sub-diode sensor 210 is set as the representative temperature. In the second mode, the process transitions to S705, and the temperature detected by the main diode sensor 209 is set as the representative temperature. In the third mode, the process transitions to S706, and the higher of the main diode and the sub-diode is set as the representative temperature. Here, the representative temperature in the third mode may be determined by the method described in Patent Document 1 and Patent Document 2.

[0034] Table 1 shows an example of determining the head drive pulse based on the representative temperature. The drive pulse input to the ink ejection heater is composed of a double pulse, a pre-pulse that is intended to warm the ink and does not lead to ejection by itself, and a main pulse that aims to eject the ink. The drive pulse is modulated by changing three parameters: the width of the pre-pulse, the interval between the pre-pulse and the main pulse, and the width of the main pulse. In this embodiment, these three parameters are managed by assigning numbers to combinations of them in a one-to-one relationship, such as PWM1 and PWM2.

[0035] [Table 1]

[0036] Each head temperature is detected at 0.5°C intervals, and the representative temperature is also calculated with a resolution of 0.5°C. The representative temperature value is associated with a PWM number, and the pre-pulse width, the interval between the pre-pulse and the main pulse, and the main pulse width change according to the temperature. For example, if the representative temperature is 50°C, the head is driven with parameters corresponding to PWM11, and if the representative temperature is 63°C, the head is driven with parameters corresponding to PWM7.

[0037] It is preferable that the drive pulse be switched at a timing at which the head temperature can be detected with high accuracy. In this embodiment, in order to prevent noise from being added to the output temperature of the diode sensor, the drive pulse is switched when the carriage is stationary and the ejection heater is not driven.

[0038] Fig. 8 shows an example in which this embodiment is effective. When an ejection heater is driven, the energy not used for ejection is converted into heat, causing the temperature in the vicinity of the driven heater to rise. In other words, the temperature distribution in the nozzle arrangement direction changes according to the print pattern. If the driven nozzles are distributed ubiquitously in a certain area, the temperature distribution also becomes more biased, making it difficult to determine an appropriate representative temperature using a representative temperature method that places emphasis on the maximum temperature. This embodiment is effective in such cases.

[0039] Continuous print scans are shown in 801 to 806. Of these, division by monitor control is performed in 801, 802, 805, and 806. That is, the driven nozzle state transitions in the order of Mode1, Mode2, Mode3, Mode3, Mode1, and Mode2.

[0040] 807 shows the distribution of the head temperature in the nozzle arrangement direction after the print scan 801 and immediately before the print scan 802. When the print data of 801 is a high-density solid pattern, the temperature near the sub-diode sensor 210 is higher than the temperature near the main diode sensor 209. According to the methods of Patent Documents 2 and 3, the higher temperature is dominant when determining the representative temperature, so the detected temperature Tsub of the sub-diode sensor 210 is dominant. However, the nozzle actually driven by 802 is the nozzle on the main diode sensor 209 side. That is, there is a concern that the ejection energy will be insufficient if the drive pulse modulation is performed assuming a temperature much higher than the actual driven nozzle. According to this embodiment, 802 can adopt the detected temperature TMain of the main diode sensor 209 as the representative temperature, taking into account that Mode 2, that is, the nozzle near the main diode sensor 209 is used, and it becomes possible to select an appropriate drive pulse for the temperature of the driven nozzle.

[0041] 808 shows the distribution of the head temperature in the nozzle arrangement direction after the print scan 804 and immediately before the print scan 805. The vertical axis shows the nozzle position, and the horizontal axis shows the temperature. When the print data of 804 is a high-density solid pattern ubiquitous on the main diode sensor 209 side, the temperature near the main diode sensor 209 is higher than the temperature near the sub-diode sensor 210. According to the methods of Patent Documents 2 and 3, TMain is dominant when determining the representative temperature. However, the nozzle actually driven by 805 is the nozzle on the sub-diode sensor 210 side. That is, there is a concern that the energy of ejection will be insufficient if the drive pulse modulation is performed assuming a temperature much higher than the actual driven nozzle. According to this embodiment, 805 can adopt TSub as the representative temperature based on the fact that Mode 1, that is, the nozzle near the sub-diode sensor 210 is used, and it becomes possible to select an appropriate drive pulse for the temperature of the driven nozzle.

[0042] In this way, by determining the head representative temperature based on the used nozzle information, the temperature of the nozzle to be used in the immediately following print scan can be reflected in the representative temperature. By modulating the head drive pulse based on the representative temperature determined in this way, it is possible to perform printing operations without degrading image quality, even in cases where a representative temperature determination method that places too much emphasis on the maximum head temperature would pose a risk to image quality.

[0043] <Second embodiment (FIGS. 9 to 12)> A second embodiment of the basic configuration of the recording apparatus described above will be described below. The same parts as those in the first embodiment may be omitted.

[0044] In the first embodiment, the drive recording element position storage unit 317 stores whether the immediately following print scan is the first division (Mode 1), the second division (Mode 2), or no division (Mode 3). By doing so, the nozzle information to be driven in the immediately following print scan is artificially stored, and the nozzle drive information stored for each print scan is acquired in S503. In this embodiment, a method of acquiring driven nozzle information more directly will be described. Here again, the black head will be described as a representative, but similar processing is also performed for color heads.

[0045] FIG. 9 is a flowchart showing an update process of the driving pulse applied to the ink ejection heater 214 of the color head and the driving pulse applied to the ink ejection heater 217 of the black head during the printing operation in this embodiment. This flowchart is almost the same as the flowchart shown in FIG. 5, but in this embodiment, the driving and printing element position storage unit 317 needs to calculate the number of nozzles to be driven in the immediately following printing scan and store the numerical value, so the execution timing is clearly shown. The flowchart continuing from S901 is a flowchart in which in S903, the immediately following nozzle drive data is calculated for each printing scan and used to determine the representative temperature. Note that the nozzle drive data of each printing scan performed from the start of printing to the end of page printing may be calculated and stored in a lump, and the calculation result may be obtained before the start of each printing scan.

[0046] FIG. 10 shows a flowchart of the subroutine called in S903, which calculates nozzle drive data and stores it in the drive and print element position storage unit 317. When the subroutine is called in S903, the process following S1001 is started. The subroutines called in S1002 and S1003 are processes following S1005, which calculate and store nozzle drive data for the color heads and black heads, respectively. When S1005 is started, first, in S1006, data to be input to the corresponding head is obtained. In the following S1007, the number of divisions N when the nozzle row or print element row of the corresponding head is divided into nozzle groups corresponding to the diode sensor positions is set. Since the nozzles and print elements are provided in one-to-one correspondence, the same result can be obtained even if they are divided by print element groups rather than by nozzle groups.

[0047] FIG. 11 shows a method of dividing the nozzle array in this embodiment. In this embodiment, the color head and the black head are provided with two diode sensors each, and the diode sensors are arranged so as to sandwich the nozzles in the nozzle arrangement direction. Therefore, in this embodiment, the nozzle array is divided so as to divide each nozzle array in half in the nozzle arrangement direction, and the nozzle groups are defined. That is, the division number N=2, and the nozzle group corresponding to the sub-diode sensor is nozzle group 1, and the nozzle group corresponding to the main diode sensor is nozzle group 2. The number of nozzles included in the nozzle array of the black head is 832. Therefore, the number of nozzles included in the nozzle group 2 corresponding to the main diode sensor 209 of the black head and the nozzle group 1 corresponding to the sub-diode sensor 210 of the black head are 416 each. The number of nozzles included in each nozzle array of the color head is 768. The number of nozzles included in the nozzle group 2 corresponding to the main diode sensor 203 of the color head and the nozzle group 1 corresponding to the sub-diode sensor 204 of the color head are 384 each. In this embodiment, each nozzle row can eject up to 1 dot in a unit area of ​​600 dpi horizontal by 1,200 dpi vertical by one printing scan, and the nozzle drive information of each nozzle group corresponds to the number of dots ejected by the printing scan. The maximum number of drives of nozzle group 1 and nozzle group 2 of the black head is expressed as 416×ScanWidth. Here, ScanWidth is expressed as the number of dots at 600 dpi, and when the image width is 8 inches, ScanWidth=4800 dots. That is, when the image width is 8 inches, the maximum number of drives of each nozzle group of the black head is 1996800 dots. On the other hand, the maximum number of drives of each nozzle group of each nozzle row of the color head is expressed as 416×ScanWidth, and when the image width is 8 inches, it is 1843200 dots. Here, when there are multiple nozzle rows in the same chip like a color head, the total value of each nozzle row may be used as the number of drives of each nozzle group of the color head. In this embodiment, three nozzle rows corresponding to cyan ink, magenta ink, and yellow ink are present in the same head, and the number of nozzle groups to be driven is managed by the sum of these values.In other words, the maximum number of drives for each nozzle group (total value) of the color head is 1843200×3=5529600 dots.

[0048] Returning to FIG. 10, in S1008, a counter value n for storing the number of nozzle drives of each nozzle group is reset to 0, and a loop is started. In S1009, the counter value n is incremented by 1, and in the following S1010, the number of times that nozzle group n is driven is calculated based on the head input data acquired in S1006, and in S1011, the calculated number of nozzle drives is stored. Finally, in S912, a comparison with the division number N is performed, and S1009 to S1011 are looped until the number of nozzle drives of all nozzle groups has been stored. In this manner, the calculation and storage of the nozzle drive data described in S903 is executed.

[0049] FIG. 12 is a subroutine executed in S904 and S906, and is a flowchart showing a method of determining a representative temperature based on nozzle drive data in the representative temperature determination unit 318. When this subroutine is started in S1201, the recorded nozzle drive data is acquired in S1202. The nozzle drive data is the number of dots for each nozzle group in the immediately following print scan, and when the nozzle division number N=2, the number of dots corresponding to nozzle group 1 is Dot1, and the number of dots corresponding to nozzle group 2 is Dot2. In S1203, it is determined whether there is a large difference in the number of dots for each nozzle group by whether the absolute value of the difference between Dot1 and Dot2 exceeds a predetermined threshold value A. If it is determined as No and the difference is small and the used nozzles are considered to be somewhat dispersed, the process proceeds to S1207, and the higher of the main diode sensor 209 and the sub diode sensor 210 is selected as the representative temperature. On the other hand, if S1203 returns Yes and it is determined that there is a certain degree of bias in the nozzles in use, then in S1204 Dot1 and Dot2 are compared, and the temperature detected by the diode sensor corresponding to the nozzle group with the greater number of nozzle drives is selected as the representative temperature. It is desirable to set threshold A according to the number of nozzles in the target head. For example, for a black head, setting it to 998,400 dots will determine the representative temperature based on the positional relationship of the nozzles in use only if there is a difference that corresponds to half the dots of each nozzle group. For a color head, setting it to 2,764,800 dots will allow the same determination as for the black head to be made.

[0050] In this way, by calculating and comparing the number of driven nozzles for each nozzle group and determining and selecting the head representative temperature, it is possible to reflect the temperature of the nozzles to be used in the immediately following print scan in the representative temperature. By modulating the head drive pulse based on the representative temperature determined in this way, it is possible to perform printing operations without degrading image quality, even in cases where a representative temperature determination method that places too much emphasis on the maximum head temperature would pose a risk to image quality.

[0051] <Third embodiment (FIG. 13)> A third embodiment of the present invention in the basic configuration of the printing apparatus described above will be described. In the second embodiment, the number of driven nozzles used in the immediately following print scan is calculated and stored for each nozzle group, and a diode sensor to be adopted as the representative temperature is selected based on the magnitude relationship of the number of driven nozzles for each nozzle group. In this embodiment, a method is shown in which the representative temperature is determined by a weighted average based on the number of driven nozzles for each nozzle group, rather than by selecting a diode sensor. In this embodiment, the method of calculating and storing the number of driven nozzles for each nozzle group is the same as in the second embodiment. Therefore, only the representative temperature determination process will be described. Parts similar to those in the above-mentioned embodiments may be omitted.

[0052] 13 is a flowchart showing a subroutine executed in S904 and S906, which shows a method of determining a representative temperature based on nozzle drive data in the representative temperature determination unit 318. When this subroutine is started in S1301, the recorded nozzle drive data is acquired in S1302. The nozzle drive data is the number of dots for each nozzle group in the immediately following print scan, and when the nozzle division number N=2, the number of dots corresponding to nozzle group 1 is Dot1, and the number of dots corresponding to nozzle group 2 is Dot2. In S1303, it is determined whether there is a large difference in the number of dots for each nozzle group by whether the absolute value of the difference between Dot1 and Dot2 exceeds a predetermined threshold value A. If it is determined No and the difference is small and the used nozzles are considered to be somewhat dispersed, the process proceeds to S1306, and the higher of the main diode sensor and the sub diode sensor is selected as the representative temperature. On the other hand, if S1303 returns Yes and it is determined that there is a certain degree of bias in the nozzles used, a representative temperature determination method that places emphasis on the highest temperature may result in an inappropriate temperature being set as the representative temperature. For this reason, in S1304 and S1305, the representative temperature is calculated by a weighted average that associates the positions of the driven nozzles with the positions of the diode sensors. In S1304, a coefficient to be used for the weighted average is calculated. In this embodiment, the coefficient to be used for the weighted average is determined by the ratio of the number of dots corresponding to each nozzle group. That is, the weighted average coefficient a1 corresponding to the sub-diode sensor present in the vicinity of nozzle group 1 and the weighted average coefficient a2 corresponding to the main diode sensor present in the vicinity of nozzle group 2 are expressed as follows, respectively.

[0053]

number

[0054] In S1305, the representative temperature is calculated based on the calculated coefficients. In this embodiment, the representative temperature T is expressed as follows using weighted average coefficients a1 and a2, the sub diode sensor output temperature Tsub, and the main diode sensor output temperature Tmain.

[0055]

number

[0056] When only nozzle group 1 on the sub-diode sensor side is driven, Dot2=0, a1=1, a2=0, and so the representative temperature=Tsub. On the other hand, when only nozzle group 2 on the main diode sensor side is driven, Dot1=0, a1=0, a2=1, and so the representative temperature=Tmain. In other words, it can be said that the third embodiment includes the second embodiment.

[0057] In this way, the number of driven nozzles is calculated for each nozzle group, and the representative temperature is determined by the weighted average of the output temperatures of each diode sensor using a weighted average coefficient calculated based on the number of driven nozzles. In this way, the temperature of the nozzle used in the immediately following print scan can be reflected in the representative temperature. By modulating the head drive pulse based on the representative temperature determined in this way, it is possible to perform a print operation without degrading image quality, even in cases where a representative temperature determination method that places too much weight on the maximum head temperature would pose a risk to image quality.

[0058] In addition, the control and design parameters of the third embodiment are more complex than those of the first and second embodiments, but it is considered to be effective in cases where the temperature distribution is extreme, for example, and where temperature changes due to smoothing of the heat distribution during print scanning are expected.

[0059] <Other embodiments> In the above embodiment, two diode sensors are provided for one print head. However, the number of diode sensors is not limited to two. Three or more diode sensors may be provided at positions where the temperatures of different nozzles can be obtained.

Claims

1. a print head having a print element array in which a plurality of print elements that generate energy for ejecting droplets are arranged in a predetermined direction, and a plurality of temperature detection elements that are arranged at different positions in the predetermined direction; a determination unit that determines a representative temperature of the print head based on information output from each of the plurality of temperature detection elements; The recording apparatus according to claim 1, wherein the determining means determines the representative temperature based on information output from the plurality of temperature detection elements and a positional relationship of a recording element to be used in an immediately following recording operation.

2. the plurality of temperature detection elements include a first detection element disposed at a first position in the predetermined direction and a second detection element disposed at a second position different from the first position in the predetermined direction, The recording device described in claim 1, characterized in that, when a recording element driven in a immediately following recording operation among the multiple recording elements of the recording element array is biased toward the vicinity of the first detection element, the determination means determines the representative temperature to be a temperature based on the first information output from the first detection element rather than based on the second information output from the second detection element, and when a recording element driven in a immediately following recording operation is biased toward the vicinity of the second detection element, the determination means determines the representative temperature to be a temperature based on the second information rather than based on the first information.

3. 3. The recording device according to claim 2, wherein the case where the recording elements driven in the immediately following recording operation are biased in the vicinity of the first detection element is a case where the recording elements driven in the immediately following recording operation are only present in the vicinity of the first detection element.

4. The recording device according to claim 3, characterized in that the case where the recording elements driven in the immediately following recording operation are biased in the vicinity of the second detection element is a case where the recording elements driven in the immediately following recording operation are only present in the vicinity of the second detection element.

5. The recording device according to claim 4, characterized in that, when the position of the recording element driven in the immediately subsequent recording operation is not biased toward either the vicinity of the first detection element or the vicinity of the second detection element, the determination means determines the representative temperature based on the first information and the second information.

6. The recording device according to claim 5, characterized in that, when the position of the recording element driven in the immediately subsequent recording operation is not biased toward either the vicinity of the first detection element or the vicinity of the second detection element, the determination means determines the representative temperature to be the higher of the first information and the second information.

7. an acquisition unit that divides the plurality of printing elements into printing element groups corresponding to the plurality of temperature detection elements, and acquires the number of printing elements to be driven for each of the printing element groups in the immediately following printing operation; 2. The printing apparatus according to claim 1, wherein the determining unit determines the representative temperature to be the temperature output by the temperature detection element corresponding to the printing element group in which the number of driven printing elements acquired by the acquiring unit is the largest.

8. a coefficient determining unit that determines a coefficient by which to multiply the temperature detected by each of the plurality of temperature detecting elements based on a positional relationship between the plurality of temperature detecting elements and the plurality of recording elements to be used in the immediately following recording operation; 2. The recording apparatus according to claim 1, wherein the determining means determines the representative temperature by multiplying each of the temperatures detected by the plurality of temperature detection elements by the coefficient determined by the coefficient determining means and taking a weighted average.

9. an acquisition unit that divides the plurality of printing elements into printing element groups corresponding to the plurality of temperature detection elements, and acquires the number of printing elements to be driven for each of the printing element groups in the immediately following printing operation; 9. The recording apparatus according to claim 8, wherein a coefficient by which the temperature output by the temperature detection element corresponding to the recording element group having the largest number of driven recording elements acquired by the acquisition means is multiplied is larger than coefficients corresponding to other recording element groups.

10. 10. The printing apparatus according to claim 1, wherein drive pulses to be applied to the plurality of printing elements in the immediately following printing operation are determined based on the representative temperature.

11. A method for determining temperature in a printing apparatus having a print head including a printing element array in which a plurality of printing elements that generate energy for ejecting droplets are arranged in a predetermined direction, and a plurality of temperature detection elements that are arranged at different positions in the predetermined direction, comprising the steps of: a determining step of determining a representative temperature of the print head based on information output from each of the plurality of temperature detection elements; The temperature determining method, wherein the determining step determines the representative temperature based on information output by the plurality of temperature detection elements and a positional relationship of a recording element to be used in an immediately following recording operation.

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