Recording device and temperature determination method

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 apparatus and a temperature determination method.

Background Art

[0002] In an inkjet recording apparatus, the physical properties such as viscosity and surface tension of the ink change depending on the temperature. When the ink is ejected, the ink ejection amount is different between when the temperature of the ink near the recording element is high and when it is low, and the image quality may deteriorate. Therefore, it is necessary to acquire the temperature of the ink.

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

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems 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 recording element array, it may not be possible to select an appropriate temperature as the representative temperature.

[0006] For example, in the method of Patent Document 2, when determining a representative temperature in a case where each of a plurality of temperatures is higher than a predetermined threshold value and there is a large temperature difference within the recording element array, the maximum temperature is selected. However, in subsequent recording, the recording element near the temperature sensor that showed the maximum temperature is not necessarily driven.

[0007] The present invention has been made in view of the above problems, and an object thereof is to determine a representative temperature of a recording element used for recording.

Means for Solving the Problems

[0008] The present invention includes a recording element row in which a plurality of recording elements that generate energy for discharging droplets are arranged in a predetermined direction, a recording head having a plurality of temperature detection elements arranged at different positions in the predetermined direction, and determination means for determining a representative temperature of the recording head based on information output from each of the plurality of temperature detection elements. The determination means determines the representative temperature based on information output by the plurality of temperature detection elements and a positional relationship of a recording element used in an immediately subsequent recording operation.

Effects of the Invention

[0009] According to the present invention, a representative temperature of a recording element used for recording can be determined.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Best Mode for Carrying Out the Invention

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

[0012] <Basic Configuration of Inkjet Recording Apparatus (Figs. 1 to 4)> Fig. 1 is a perspective view partially showing the internal configuration of a recording apparatus 100 which is a typical embodiment of the present embodiment. As shown in Fig. 1, the recording apparatus 100 includes a paper feeding unit 101, a conveying unit 102, a recording unit 103, and a recovery unit 104. The paper feeding unit 101 supplies a recording medium into the apparatus main body. The conveying unit 102 conveys the recording medium supplied by the paper feeding unit 101 in the Y direction (conveying 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 image quality of the recorded image.

[0013] The paper feeding unit 101 feeds a recording medium into the apparatus main body. The recording medium stacked on the paper feeding unit 101 is picked up one by one by a pickup roller (not shown) and a paper feeding roller driven by a paper feeding motor (not shown), and is sent out and fed to the conveying unit 102. There is a recording medium end detection sensor (not shown) upstream of the conveying roller 105, and when the leading end of the recording medium passes through the sensor, the passage can be detected.

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

[0015] The recording unit 103 records an image by ejecting droplets (ink in this embodiment) onto the recording medium from a recording head 107 described later based on image data. The recording unit 103 includes a carriage 106 capable of reciprocating in the X direction (scanning direction) intersecting the 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 able to reciprocate in the X direction along a guide rail installed in the recording device. The carriage 106 reciprocates in the recording area when recording on the recording medium via a carriage belt 109 driven by a carriage motor (not shown). 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. When the carriage 106 is moving, recording is performed on the recording medium by ejecting ink from the recording heads 107, 108 of the recording unit 103. The recording medium is sandwiched between a discharge roller (not shown) that is synchronously driven with the conveyance roller 105 by the conveyance unit 102 and an impeller (not shown) pressed against the discharge roller, and is discharged out of the recording device. At this time, a recording medium end detection sensor (not shown) can detect the passage when the rear end of the recording medium passes through the sensor.

[0017] The recovery unit 104 includes a wiping mechanism, a capping mechanism, and a suction mechanism. The wiping mechanism restores the state of the discharge port surface to a normal state by wiping ink droplets adhering to the surface (discharge port surface) where the discharge ports of the recording heads 107, 108 are provided. The capping mechanism covers the discharge ports. The suction mechanism sucks ink from the discharge ports by the capping mechanism.

[0018] Figure 2 is a schematic configuration diagram showing the configuration of the recording head 107 of the present embodiment. The recording head 107 (hereinafter also referred to as the color head) is a color head that discharges cyan ink, magenta ink, and yellow ink, and the recording head 108 (hereinafter also referred to as the black head) is a black head that discharges black ink. Fig. 2(a) is a perspective view showing the recording head 107. Note that the perspective view of the recording head 108 is omitted because it is substantially the same as the perspective view of the recording head 107. Fig. 2(b-1) is a bottom view of the recording head 107 viewed in the Z direction. Fig. 2(b-2) is a bottom view of the recording head 108 viewed in the Z direction. Fig. 2(c-1) is an enlarged view showing the cyan ink ejection port row 205 of the recording head 107. Note that the enlarged views of the magenta ink ejection port row 206 and the yellow ink ejection port row 207 are omitted because they are the same as the enlarged view of the cyan ink ejection port row. Fig. 2(c-2) is an enlarged view showing the black ink ejection port row 211 of the recording head 108.

[0019] The recording head 107 receives a recording signal from the recording apparatus main body via the contact pad 201 and is supplied with the electric power necessary for driving the recording head. The recording 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 recording head substrate. The recording chip 202 is also provided with an ejection port row 205 for ejecting cyan ink, an ejection port row 206 for ejecting magenta ink, and an ejection port row 207 for ejecting yellow ink. Further, a sub heater 208 for heating the ink is provided so as to surround the ejection port rows 205, 206, and 207. This sub heater heats or does not heat the recording head substrate and the ink depending on whether or not a voltage is applied. Discharge ports (nozzles) 213 for discharging 5 pl of ink are arranged on both sides of the ink liquid chamber 218, and 5 pl ink discharge heaters 214 are arranged directly below (+Z direction side) of each discharge port. The number of discharge ports 213 is 768, and the interval between the discharge ports is 1 / 1200 inch. Therefore, the recording head 107 of the present embodiment is configured such that the recording pixel density is 1200 dpi.

[0020] Regarding the recording head 108, it is the same as the recording head 107 in that it receives a recording signal from the recording apparatus main body via a contact pad and is supplied with the power necessary for driving the recording head. On the recording chip of the recording head 108, a main diode sensor 209 for detecting the temperature of the recording head substrate, a sub-diode sensor 210, and a discharge port row 211 for discharging black ink are arranged. Further, a sub-heater 212 for heating ink is provided so as to sandwich the discharge port row 211. This sub-heater heats or does not heat the recording head substrate and the ink depending on whether a voltage is applied or not. Discharge ports 216 for discharging 9 pl of ink are arranged on both sides of the ink liquid chamber 215, and 9 pl ink discharge heaters 217 are arranged directly below (+Z direction side) each discharge port. The number of discharge ports 216 is 832, and the interval between the discharge ports is 1 / 1200 inch. Therefore, the recording head 108 of the present embodiment is configured such that the recording pixel density is 1200 dpi.

[0021] The ink discharge heaters 214 and 217 can keep the ink warm by being given drive pulses that do not cause the ink to be discharged. Hereinafter, such temperature-keeping control is called short-pulse heating control. The recording apparatus of the present embodiment adjusts the temperature of the recording head substrate and the ink temperature (hereinafter collectively referred to as the head temperature) by short-pulse heating control and the control of the sub-heater.

[0022] The recording apparatus of the present embodiment adjusts the head temperature by the sub-heater and short-pulse heating control, and based on the output value of the main diode sensor 203, switches the heating / non-heating of the recording head substrate to approach the target temperature and performs feedback control. Similarly for the recording head 108, based on the output value of the main diode sensor 209, the heating / non-heating of the recording head substrate is switched to approach the target temperature and feedback control is performed.

[0023] In the recording apparatus according to the present embodiment, when the carriage 106 is moving, recording is performed on a recording medium by discharging ink from the recording heads 107 and 108 of the recording unit 103. The ink discharge is performed by applying a drive pulse for discharge to the ink discharge heaters 214 and 217, which are recording elements that generate energy. The drive pulse is modulated so as to keep the discharge amount constant based on the head temperatures output from the main diode sensors 203 and 209 and the sub diode sensors 204 and 210. The acquisition of the head temperature used for modulating the drive pulse is preferably performed at a timing when the ink discharge heater is not driven in order to reduce the influence of noise.

[0024] FIG. 3 is a block diagram showing the overall control configuration of the recording apparatus according to the present embodiment. Each component of this control configuration can be broadly classified 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 conveyance control circuit 307 that respectively access the main bus line 305. Further, the software control means includes an image input unit 303, an image signal processing unit 304 corresponding thereto, a drive recording element position storage unit 317 that stores recording elements used in the immediately subsequent recording operation based on the processed image signal, a representative temperature determination unit 318 that determines a representative temperature for each recording head based on the head temperature information from the diode sensors 203, 204, 209, 210 acquired by the head temperature control circuit 314, and a control unit CPU 300, which respectively access the main bus line 305. The CPU 300 usually has a ROM 301 and a RAM 302, gives appropriate recording conditions to the input information, and drives the ink ejection heaters 214 and 217 in the recording heads 107 and 108 to perform recording. Further, a program for executing a recovery timing chart of the recording head is stored in the ROM 301 in advance, and recovery conditions such as preliminary ejection conditions are given to the recovery operation control circuit 309 and the recording heads 107 and 108 as necessary. The recovery motor 310 drives the recording heads 107 and 108, and the wiping blade 311, the cap 312, and the suction pump 313 that are spaced apart from and opposed to them. The head temperature control circuit 314 determines the drive conditions of the sub-heaters 208 and 212 on the recording heads 107 and 108 based on the output values of a thermistor 315 that detects the ambient temperature, which is the temperature around the recording head, and the main diode sensors 203 and 209 that detect the head temperature. Then, the head drive control circuit 316 drives the sub-heaters 208 and 212 based on the determined drive conditions. The head drive control circuit 316 also drives the ink ejection heaters 214 and 217 on the recording heads 107 and 108. By driving the ink ejection heaters 214 and 217, the recording heads 107 and 108 are made to perform preliminary ejection, ink ejection, and ink temperature adjustment for temperature control.A program for performing temperature control is stored, for example, in the ROM 301, and detection of the recording head temperature and driving of the sub-heater 208 are executed via the head temperature control circuit 314, the head drive control circuit 316, etc. The head drive control circuit 316 can perform the above-described drive pulse modulation control by driving the ink ejection heaters 214 and 217 with a drive signal composed of a pre-pulse and a main pulse. The storage of the drive element information in the drive recording element position storage unit 317 may be performed all at once for all recording scans before the start of recording, or only the information corresponding to each recording scan may be stored before each recording scan is executed.

[0025] FIG. 4 is a block diagram showing the flow of processing in the head temperature control circuit 314 and processing performed software-wise through the ROM 301 / RAM 302. When voltages based on the recording head temperature are input from the recording heads 107 and 108 and the main diode sensors 203 and 209 provided therein to the head temperature control circuit 314, the voltage values are amplified by the amplifier 401. Then, the amplified voltage values are digitized by the AD converter 402. The digitized diode sensor voltage value ADMain is converted into the main diode temperature TMain by the ADMain-temperature conversion formula 403 stored in the ROM 301. On the other hand, when voltages based on the recording head temperature are input from the sub-diode sensors 204 and 210 to the head temperature control circuit 314, they are digitized by the AD converter 404. The digitized sub-diode voltage value ADSUB is converted into the sub-diode temperature TSub by the 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 the head temperature detection unit 406 and used for the control of the present embodiment. In addition, in order to accurately perform the above-described head temperature control by the sub-heater and short pulse heating, and modulation of 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)> The first embodiment of the present invention will be described with respect to the basic configuration of the recording apparatus described above.

[0027] FIG. 6 shows the correspondence between recording data, recording nozzles, and nozzle use modes. When the number of simultaneously driven recording elements increases, there is a concern that in addition to the head temperature rising sharply due to ink ejection, the power consumption also increases. For this reason, for the purpose of suppressing the head temperature rise and power consumption, when the number of nozzles used in the recording operation exceeds a predetermined threshold, monitor control may be adopted in which the recording operation is divided into a plurality of times and performed. In the present embodiment, in the image signal processing unit 304, when it is determined that the total ejection dot number of the immediately subsequent recording scan exceeds a predetermined threshold, the monitor control is activated. When the monitor control is activated, the recording data is divided into two in the recording element array direction (predetermined direction), and recording is performed in two recording scans. In the first divided recording scan, the recording element side on the sub-diode sensor 210 side is driven, and in the second divided recording scan, the recording element side on the main diode sensor 209 side is driven. In the present embodiment, by storing and acquiring in the drive recording element position storage unit 317 whether the immediately subsequent recording scan is the first divided (Mode1), the second divided (Mode2), or not divided (Mode3), pseudo drive nozzle information is acquired.

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

[0029] When the image input unit 303 receives a recording command, the recording operation shown in S501 is started. In S502, the output temperatures of the diode sensors 203, 204, 209, and 210 provided in the color head and the black head 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 acquired. Thereafter, in S503, the position information of the recording elements (hereinafter also referred to as nozzles) used in the immediately subsequent recording scan stored in the drive recording element position storage unit 317 is acquired.

[0030] In subsequent S504, based on the detected temperature of each diode sensor of the color head obtained in S502 and the drive nozzle information of the immediately following recording scan obtained in S503, the representative temperature determination unit 318 determines the representative temperature used for the determination during the drive pulse modulation of the color head in the immediately following recording scan. In S505, based on the representative temperature determined in S504, the drive pulse of the color head in the immediately following recording scan is determined. In S506 and S507, the same processing as that performed on the color head in S504 and S505 is applied to the black head. Here, S505 only needs to be after S504, and S507 only needs to be after S506. The order of determining the representative temperature of the color head in S504 and the representative temperature of the black head in S506 may be reversed, or S504 and S506 may be performed together first and then S505 and S507 may be performed.

[0031] After determining the drive pulses of the color head and the black head, recording scanning is started in S508. Recording scanning is to drive each ink ejection heater to eject ink while scanning and moving the carriage to record an image. After the recording scan ends in S509, it is confirmed in S510 whether the recording of the page has ended. If it is still necessary to record the page, the process returns to S502. When it is confirmed in S510 that the page recording has ended, the process proceeds to S511, and the recording is ended and the recording medium is ejected.

[0032] FIG. 7 is a flowchart showing the representative temperature determination process for determining the head representative temperature used for the determination of the heater drive pulse modulation based on the head detection temperature and the nozzle information used in the immediately following recording scan in the representative temperature determination unit 318 shown in S504 and S506. This flowchart is executed for the color head in S504 and for the black head in S506 respectively, but the content is the same. In FIG. 7, the black head is described as a representative.

[0033] When the representative temperature determination process is started in S701, the process proceeds to S702, and it is acquired in the drive recording element position storage unit 317 which mode the nozzle to be used in the immediately subsequent recording operation is in. As described above, in the present embodiment, the usage of the nozzle is classified into three types of modes. The first mode (Mode1) is the nozzle mode used for the first split at the time of split printing activation, that is, the mode in which the drive nozzles are ubiquitous on the side of the sub-diode sensor 210. The second mode (Mode2) is the nozzle mode used for the second split at the time of split printing activation, that is, the mode in which the drive nozzles are ubiquitous on the side of the main diode sensor 209. The third mode (Mode3) is the nozzle mode when split printing is not performed, that is, the mode in which the drive nozzles can be unevenly distributed on either the side of the main diode sensor 209 or the side of the sub-diode sensor 210. In S703, conditional branching is performed based on the acquired mode. In the case of the first mode, the process proceeds to S704, and the detected temperature of the sub-diode sensor 210 is set as the representative temperature. In the case of the second mode, the process proceeds to S705, and the detected temperature of the main diode sensor 209 is set as the representative temperature. In the case of the third mode, the process proceeds to S706, and the higher temperature 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 methods described in Patent Document 1 and Patent Document 2.

[0034] Table 1 shows an example when determining the head drive pulse based on the representative temperature. The drive pulse applied to the ink ejection heater is composed of a pre-pulse for the purpose of heating the ink and which alone does not lead to ejection, and a double pulse of the main pulse for the purpose of ejection. By changing three things: the width of the pre-pulse, the interval between the pre-pulse and the main pulse, and the width of the main pulse, the drive pulse is modulated. In the present embodiment, these three parameters are numbered one-to-one like PWM1 and PWM2 for their combinations and managed.

[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 array direction after the recording scan 801 and immediately before the recording scan 802. When the recording data of 801 is a high-density solid pattern, for example, the temperature near the sub-diode sensor 210 becomes higher than the temperature near the main-diode sensor 209. According to the methods of Patent Document 2 and Patent Document 3, when determining the representative temperature, the higher temperature is dominant, so the detected temperature Tsub of the sub-diode sensor 210 becomes dominant. However, the nozzles actually driven at 802 are the nozzles on the main-diode sensor 209 side. That is, there is a concern that the ejection energy may be insufficient by performing drive pulse modulation assuming a temperature much higher than that of the actual drive nozzles. According to the present embodiment, 802 is Mode2, that is, based on the fact that the nozzles near the main-diode sensor 209 are used, the detected temperature TMain of the main-diode sensor 209 can be adopted as the representative temperature, and it becomes possible to select an appropriate drive pulse for the temperature of the drive nozzles.

[0041] 808 shows the distribution of the head temperature in the nozzle array direction after the recording scan 804 and immediately before the recording scan 805. The vertical axis indicates the nozzle position, and the horizontal axis indicates the temperature. When the recording data of 804 is a high-density solid pattern ubiquitous on the main-diode sensor 209 side, for example, the temperature near the main-diode sensor 209 becomes higher than the temperature near the sub-diode sensor 210. According to the methods of Patent Document 2 and Patent Document 3, when determining the representative temperature, TMain becomes dominant. However, the nozzles actually driven at 805 are the nozzles on the sub-diode sensor 210 side. That is, there is a concern that the ejection energy may be insufficient by performing drive pulse modulation assuming a temperature much higher than that of the actual drive nozzles. According to the present embodiment, 805 is Mode1, that is, based on the fact that the nozzles near the sub-diode sensor 210 are used, TSub can be adopted as the representative temperature, and it becomes possible to select an appropriate drive pulse for the temperature of the drive nozzles.

[0042] In this way, by determining the head representative temperature based on the usage nozzle information, the temperature of the nozzle used in the immediately subsequent recording scan can be reflected in the representative temperature. By modulating the head drive pulse based on the representative temperature determined in this manner, even in a case where there is a risk of image quality degradation in the representative temperature determination method that emphasizes the head maximum temperature, it becomes possible to perform the recording operation without degrading the 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. Parts similar to 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 subsequent recording scan is the first split (Mode1), the second split (Mode2), or not split (Mode3). By doing so, the nozzle information driven in the immediately subsequent recording scan is pseudo-stored, and the nozzle drive information stored for each recording scan is acquired in S503. In this embodiment, a method for acquiring more direct drive nozzle information will be described. Here, the black head will be described as a representative, but the same processing is performed for the color head.

[0045] FIG. 9 is a flowchart showing the update process of the drive pulse applied to the ink ejection heater 214 of the color head and the drive pulse applied to the ink ejection heater 217 of the black head during the recording operation in this embodiment. This flowchart is almost the same as the flowchart shown in FIG. 5, but in this embodiment, it is necessary to calculate the number of nozzle drives in the immediately subsequent recording scan in the drive recording element position storage unit 317 and store the numerical value, so the implementation timing is specified. The flowchart continuing from S901 is a flowchart for calculating the immediately subsequent nozzle drive data for each recording scan and using it to determine the representative temperature in S903. Note that a configuration may be adopted in which the nozzle drive data for each recording scan performed from immediately after the start of recording until the end of page recording is calculated and stored in a batch, and the calculation result is acquired before the start of each recording scan.

[0046] FIG. 10 shows a flowchart of a subroutine called at S903, which calculates nozzle drive data and stores it in the drive recording element position storage unit 317. When the subroutine is called at S903, the process consecutive to S1001 starts. The subroutines called at S1002 and S1003 are processes consecutive to S1005, which respectively execute the calculation and storage of the nozzle drive data for the color head and the black head. When S1005 starts, first, the data input to the corresponding head is acquired at S1006. In the subsequent S1007, the number of divisions N when dividing the nozzle array or the recording element array of the corresponding head into nozzle groups associated with the diode sensor positions is set. Since the nozzles and the recording elements are provided in a one-to-one correspondence, it is the same even if divided into recording element groups instead of nozzle groups.

[0047] Fig. 11 shows the method of dividing the nozzle rows in this embodiment. In this implementation, there are two diode sensors each provided in the color head and the black head, and each diode sensor is arranged so as to sandwich the nozzles in the nozzle array direction. Therefore, in this embodiment, each nozzle row is divided in the nozzle array direction so as to bisect it, and nozzle groups are defined. That is, the number of divisions N = 2, the nozzle group corresponding to the sub-diode sensor is defined as nozzle group 1, and the nozzle group corresponding to the main diode sensor is defined as nozzle group 2. The number of nozzles included in the nozzle row of the black head is 832. Therefore, the number of nozzles included in nozzle group 2 corresponding to the main diode sensor 209 and nozzle group 1 corresponding to the sub-diode sensor 210 of the black head are each 416. The number of nozzles included in each nozzle row of the color head is 768 each. The number of nozzles included in nozzle group 2 corresponding to the main diode sensor 203 and nozzle group 1 corresponding to the sub-diode sensor 204 of the color head are each 384. In this embodiment, each nozzle row can eject up to 1 dot into a unit area of 600 dpi horizontally × 1,200 dpi vertically by one recording scan, and the nozzle drive information of each nozzle group corresponds to the number of dots ejected in the recording scan. The maximum drive numbers of nozzle group 1 and nozzle group 2 of the black head are represented by 416 × ScanWidth. Here, ScanWidth is represented by the number of dots at 600 dpi, and when the image width is 8 inches, ScanWidth = 4800 dots. That is, the maximum drive number of each nozzle group of the black head when the image width is 8 inches is 1,996,800 dots. On the other hand, the maximum drive number of each nozzle group of each nozzle row of the color head is represented by 416 × ScanWidth, and when the image width is 8 inches, it is 1,843,200 dots. Here, in the case of having a plurality of nozzle rows in the same chip like the color head, the total value of each nozzle row may be adopted as the drive number of each nozzle group of the color head. In this embodiment, since three nozzle rows corresponding to cyan ink, magenta ink, and yellow ink exist in the same head, the drive number of the nozzle group is managed with the total value of these.That is, the maximum drive count of each nozzle group (total value) of the color head is 1843200 × 3 = 5529600 dots.

[0048] Return to FIG. 10. In S1008, the counter value n for storing the nozzle drive count of each nozzle group is reset to 0, and the loop is started. In S1009, the counter value n is incremented by 1. In the subsequent S1010, based on the head input data acquired in S1006, the drive count of nozzle group n is calculated, and the calculated nozzle drive count is stored in S1011. Finally, by performing a comparison determination with the division number N in S912, S1009 to S1011 are looped until the storage of the nozzle drive counts of all nozzle groups is completed. In this way, the calculation and storage of the nozzle drive data described in S903 are 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 will be described with respect to the basic configuration of the recording apparatus described above. In the second embodiment, a method of calculating and storing the number of drive nozzles used in the immediately subsequent recording scan for each nozzle group, and selecting a diode sensor to be adopted as the representative temperature based on the magnitude relationship of the number of drive nozzles for each nozzle group was shown. In the present embodiment, a method of determining the representative temperature by weighted average based on the number of drive nozzles for each nozzle group, rather than by selecting a diode sensor, will be shown. In the present embodiment, the method of calculating and storing the number of drive nozzles for each nozzle group is the same as that in the second embodiment. For this reason, only the representative temperature determination process will be described. Parts that are the same as those in the above-described embodiment may be omitted.

[0052] Fig. 13 shows a flowchart of a subroutine executed in S904 and S906, which is a method for determining a representative temperature in the representative temperature determination unit 318 based on nozzle drive data. When this subroutine starts at S1301, at S1302, the recorded nozzle drive data is acquired. The nozzle drive data is the number of dots for each nozzle group in the immediately subsequent recording scan. When the number of nozzle divisions 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. At S1303, it is determined whether there is a large difference in the number of dots of each nozzle group, that is, whether the absolute value of the difference between Dot1 and Dot2 exceeds a predetermined threshold A. If it is determined as No and there is a small difference and the used nozzles are considered to be somewhat dispersed, the process proceeds to S1306, and the higher one of the main diode sensor and the sub-diode sensor is selected as the representative temperature. On the other hand, if it is determined as Yes at S1303 and it is determined that there is a certain degree of bias in the used nozzles, in the representative temperature determination method that emphasizes the highest temperature, there is a risk of using an inappropriate temperature as the representative temperature. Therefore, from S1304 to S1305, the representative temperature is calculated by weighted average associating the drive nozzle position and the diode sensor position. At S1304, the coefficient used for the weighted average is calculated. In this embodiment, the coefficient used for the weighted average is determined as 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 existing near nozzle group 1 and the weighted average coefficient a2 corresponding to the main diode sensor existing near nozzle group 2 are expressed as follows respectively.

[0053] [Number]

[0054] At S1305, the representative temperature is calculated based on the calculated coefficient. In this embodiment, the representative temperature T is expressed as follows using the 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 recording element array in which a plurality of recording elements that generate energy for ejecting droplets are arranged in a predetermined direction, a recording head having a plurality of temperature detection elements arranged at different positions in the predetermined direction, Determining means for determining a representative temperature of the recording head based on information output from each of the plurality of temperature detection elements, The recording apparatus, wherein the determining means determines the representative temperature based on information output by the plurality of temperature detection elements and a positional relationship of a recording element used in a immediately subsequent recording operation.

2. The plurality of temperature detection elements include a first detection element arranged at a first position in the predetermined direction and a second detection element arranged at a second position different from the first position in the predetermined direction, When the recording element driven in the immediately subsequent recording operation is biased near the first detection element among the plurality of recording elements in the recording element array, the determining means does not base the representative temperature on second information output from the second detection element, but sets the temperature based on first information output from the first detection element as the representative temperature; when the recording element driven in the immediately subsequent recording operation is biased near the second detection element, the determining means does not base the representative temperature on the first information, but sets the temperature based on the second information as the representative temperature. The recording apparatus according to claim 1.

3. The case where the recording element driven in the immediately subsequent recording operation is biased near the first detection element means that the recording element driven in the immediately subsequent recording operation exists only near the first detection element. The recording apparatus according to claim 2.

4. The case where the recording element driven in the immediately subsequent recording operation is biased near the second detection element means that the recording element driven in the immediately subsequent recording operation exists only near the second detection element. The recording apparatus according to claim 3.

5. When the position of the recording element driven in the immediately subsequent recording operation is not biased toward the vicinity of the first detection element nor the vicinity of the second detection element, the determination means determines the representative temperature based on the first information and the second information. The recording apparatus according to claim 4, characterized in that.

6. When the position of the recording element driven in the immediately subsequent recording operation is not biased toward the vicinity of the first detection element nor the vicinity of the second detection element, the determination means sets, as the representative temperature, the higher temperature of the first information and the second information. The recording apparatus according to claim 5, characterized in that.

7. The recording element group is divided into a plurality of recording element groups associated with the plurality of temperature detection elements, and acquisition means for acquiring the number of driving of the recording elements for each recording element group in the immediately subsequent recording operation is provided. The determination means sets, as the representative temperature, the temperature output by the temperature detection element corresponding to the recording element group in which the number of driving of the recording elements acquired by the acquisition means is the largest. The recording apparatus according to claim 1, characterized in that.

8. Coefficient determination means for determining a coefficient to be multiplied by the temperature detected by each of the plurality of temperature detection elements based on the positional relationship between the plurality of temperature detection elements and the plurality of recording elements used in the immediately subsequent recording operation is provided. The determination means determines the representative temperature by multiplying the temperature detected by each of the plurality of temperature detection elements by the coefficient determined by the coefficient determination means and performing weighted averaging. The recording apparatus according to claim 1, characterized in that.

9. The recording element group is divided into a plurality of recording element groups associated with the plurality of temperature detection elements, and acquisition means for acquiring the number of driving of the recording elements for each recording element group in the immediately subsequent recording operation is provided. The coefficient to be multiplied by the temperature output by the temperature detection element corresponding to the recording element group in which the number of driving of the recording elements acquired by the acquisition means is the largest is larger than the coefficients corresponding to the other recording element groups. The recording apparatus according to claim 8, characterized in that.

10. The recording apparatus according to any one of claims 1 to 9, characterized in that drive pulses applied to the plurality of recording elements in the immediately subsequent recording operation are determined based on the representative temperature.

11. A temperature determination method in a recording apparatus including a recording head having a recording element array in which a plurality of recording elements for generating energy for discharging droplets are arranged in a predetermined direction, and a plurality of temperature detection elements arranged at different positions in the predetermined direction, comprising: a determination step of determining a representative temperature of the recording head based on information output from each of the plurality of temperature detection elements; The determination step determines the representative temperature based on information output by the plurality of temperature detection elements and a positional relationship of the recording elements used in an immediately subsequent recording operation.

Images