Recording device, recording device control method, and program

Abstract

To obtain accurate temperature data of a printhead regardless of changes in data included in a control signal of the printhead. [Solution] The recording device is a recording device comprising a recording head (105), a controller, and a temperature acquisition unit (321), in which part of the line used to transmit a control signal from the controller to the recording head (105) is common to part of the line electrically connected to the temperature sensor (25) in the recording head (105), and is also provided with a counter (318) that counts the amount of change in data within a specified period in the control signal sent from the controller, and a temperature correction unit (322) that calculates a correction value to correct the output value from the temperature sensor (25) based on the amount of change in data within the specified period counted by the counter (318).

Description

[Technical Field]

[0001] The present disclosure relates to a recording device, a control method for a recording device, and a program. [Background technology]

[0002] Inkjet recording devices are known as recording devices that record images on a recording medium. Inkjet recording devices record images by ejecting ink from a recording head onto the recording medium. The recording head includes an element substrate on which a plurality of recording elements are provided that generate thermal energy for ejecting ink. In inkjet recording devices, if the temperature near the recording elements is low, the amount of ink ejected may be too small, which may result in a decrease in the density of the image recorded on the recording medium. In order to prevent a decrease in image density caused by a low temperature near the recording elements, it is known to provide heating elements for heating the ink on the element substrate in addition to the recording elements, and to drive the heating elements when recording an image.

[0003] When a heating element is provided on an element substrate, it is desirable to acquire temperature data of the printhead while the printhead is printing an image. In this case, the printhead is provided with a temperature sensor such as a diode sensor. However, during image printing, crosstalk occurs from the data transfer clock, transfer data, latch signals, etc., which generates induced noise in the output from the temperature sensor provided in the printhead. For this reason, it is difficult to acquire accurate temperature data of the printhead while printing an image.

[0004] In Patent Document 1, one print cycle of the printhead, which is determined based on the printhead drive frequency, is divided into an active section necessary for driving the printhead and an inactive section in which temperature data signals are acquired from a temperature sensor. During the active section, signals necessary for driving the printhead are transferred to the printhead, while during the inactive section, the temperature data signals output from the printhead are read. This makes it possible to acquire temperature data without being affected by crosstalk of control signals, even while an image is being printed. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-144039 Summary of the Invention [Problem to be solved by the invention]

[0006] However, even with the technology disclosed in Patent Document 1, accurate temperature data of the printhead may not be obtained depending on the printhead's structure. For example, to reduce costs, a known structure is one in which part of the line used to transmit control signals to the printhead is shared with part of the line electrically connected to the temperature sensor. In a printhead with such a structure, changes in the data included in the printhead's control signals can cause crosstalk in the control signals, which can change the output from the temperature sensor, potentially making it impossible to obtain accurate printhead temperature data.

[0007] An object of the present disclosure is to make it possible to acquire accurate temperature data of a print head regardless of changes in data included in a control signal for the print head. [Means for solving the problem]

[0008] A printing apparatus according to one aspect of the present disclosure comprises an element substrate on which printing elements that generate thermal energy for ejecting ink are provided, a printing head having a temperature sensor provided on the element substrate to detect temperature, a controller that sends a control signal to the printing head to drive the printing elements, and a temperature acquisition unit that reads the output value from the temperature sensor when a control signal is sent from the controller to acquire temperature data, wherein a portion of the line used to transmit the control signal from the controller and a portion of the line electrically connected to the temperature sensor in the printing head are common, and the printing apparatus comprises: a counter that counts the amount of change in data within a predetermined period in the control signal sent from the controller; and a temperature correction unit that calculates a correction value to correct the output value from the temperature sensor based on the amount of change in data within the predetermined period counted by the counter. [Effects of the Invention]

[0009] According to the present disclosure, accurate temperature data of the print head can be obtained regardless of changes in the data included in the control signal of the print head. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 2 is a schematic diagram illustrating the internal configuration of the recording apparatus. [Figure 2] FIG. 2 is an explanatory diagram for explaining a recording head. [Figure 3] FIG. 2 is a block diagram showing a control system of the recording apparatus. [Figure 4] FIG. 2 is a block diagram showing a part of a control system of the printing apparatus. [Figure 5] FIG. 2 is a diagram showing a driving block and a temperature acquisition block. [Figure 6] FIG. 10 is an explanatory diagram illustrating a reading error of an output value from a temperature sensor. [Figure 7] FIG. 4 is a schematic diagram showing a change in output from a temperature sensor. [Figure 8] 10 is a flowchart showing a correction amount determination process. [Figure 9] 10 is a flowchart illustrating a correction formula calculation process. [Figure 10] 10 is a flowchart illustrating a control method for the recording apparatus. [Figure 11] FIG. 10 is an explanatory diagram illustrating a specific example in which a counter counts the amount of change in data. DETAILED DESCRIPTION OF THE INVENTION

[0011] Preferred embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. Note that the following embodiments do not limit the scope of the present disclosure, and not all combinations of features described in the following embodiments are necessarily essential to the solutions of the present disclosure. Note that the same components will be described with the same reference numerals.

[0012] <<Embodiment 1>> <Configuration of recording device> 1 is a schematic diagram showing the internal configuration of an inkjet recording apparatus 100 (hereinafter referred to as recording apparatus 100) according to this embodiment. In addition, in Fig. 1 and Fig. 2, the Z direction indicates the direction of gravity, and intersects (orthogonal in this embodiment) with the XY plane defined by the X and Y directions.

[0013] 1, a recording apparatus 100 according to this embodiment includes a supply unit 101, a discharge unit 102, an upstream transport roller pair 103, and a downstream transport roller pair 104. The recording apparatus 100 also includes a first recording head 105, a second recording head 106, a third recording head 107, and a fourth recording head 108. The recording apparatus 100 records an image on the recording medium P by ejecting ink from the first to fourth recording heads 105 to 108 and causing the ink to land on the recording medium P.

[0014] The recording medium P supplied from the supply unit 101 is conveyed at a predetermined speed in a conveying direction (+X direction) perpendicular to the extension direction (Y direction) of the recording head while being sandwiched between an upstream conveying roller pair 103 and a downstream conveying roller pair 104. The recording medium P conveyed by the upstream conveying roller pair 103 and the downstream conveying roller pair 104 is discharged from the discharge unit 102. The recording medium P moves in the conveying direction from the supply unit 101 toward the discharge unit 102. The conveying direction is also referred to as the cross direction.

[0015] The first to fourth print heads 105 to 108 are arranged in a line along the print direction between the upstream transport roller pair 103 and the downstream transport roller pair 104. The first to fourth print heads 105 to 108 eject ink in the direction of gravity (+Z direction) according to print data. For example, the first print head 105 ejects cyan ink, the second print head 106 ejects magenta ink, the third print head 107 ejects yellow ink, and the fourth print head 108 ejects black ink. In the following description, cyan ink will be referred to as C ink, magenta ink will be referred to as M ink, yellow ink will be referred to as Y ink, and black ink will be referred to as K ink. The C ink, M ink, Y ink, and K ink are supplied to the first to fourth print heads 105 to 108 from four ink tanks (not shown) that store ink of each color via tubes (not shown).

[0016] In this embodiment, the recording medium P may be continuous paper held in a roll in the supply unit 101, or may be cut paper that has been pre-cut to a standard size. If the recording medium P is continuous paper, after the recording operation by the first to fourth recording heads 105 to 108 is completed, the recording medium P is cut to a predetermined length (size) by a cutter 109, and the cut sheets are sorted into paper output trays by size in the output unit 102. The recording device 100 is provided with a temperature sensor (not shown) for acquiring the temperature inside the recording device 100.

[0017] <Recording head configuration> Next, the first to fourth printheads 105 to 108 will be described. The second printhead 106, the third printhead 107, and the fourth printhead 108 have the same configuration as the first printhead 105. Therefore, the first printhead 105 will be described in detail, and detailed descriptions of the second printhead 106, the third printhead 107, and the fourth printhead 108 will be omitted. In the following description, the element substrate provided in the printhead will be referred to as a heater board.

[0018] 2A and 2B are explanatory diagrams illustrating the first print head 105. FIG. 2A is a plan view of the first print head 105 seen from below. FIG. 2B is a plan view of the first heater board HB0. FIG. 2C is a schematic diagram showing grouping in the ejection port array 22.

[0019] As shown in FIG. 2(a), the first printhead 105 includes a first heater board HB0, a second heater board HB1, a third heater board HB2, a fourth heater board HB3, a fifth heater board HB4, and a sixth heater board HB5. The first to sixth heater boards (element substrates) HB0 to HB5 are arranged side by side along the extension direction (Y direction) of the first printhead 105. Among the first to sixth heater boards HB0 to HB5, the longitudinal ends of adjacent heater boards partially overlap each other. By using a printhead in which the first to sixth heater boards HB0 to HB5 are arranged side by side in the Y direction, it is possible to perform printing on the entire area of ​​the print medium P, which has a long width in the Y direction, just as in the case of using a long printhead consisting of only one heater board.

[0020] The second heater board HB1, the third heater board HB2, the fourth heater board HB3, the fifth heater board HB4, and the sixth heater board HB5 have the same configuration as the first heater board HB0. Therefore, the first heater board HB0 will be described in detail, and detailed descriptions of the second heater board HB1, the third heater board HB2, the fourth heater board HB3, the fifth heater board HB4, and the sixth heater board HB5 will be omitted.

[0021] As shown in FIG. 2(b), the first heater board HB0 includes a silicon substrate 21, a sub-heater 24, and a temperature sensor 25. The silicon substrate 21 is formed in the shape of a rectangular plate that is elongated in the Y direction. A discharge port member 23 having a discharge port array 22 is bonded to the silicon substrate 21 by adhesive or the like. The discharge port member 23 is formed in the shape of a plate that covers one surface (the +Z direction side) of the silicon substrate 21 using a resin material, a metal material, or the like. An ink flow path (not shown) that communicates with the multiple discharge ports that make up the discharge port array 22 is formed between the discharge port member 23 and the silicon substrate 21.

[0022] The ejection port array 22 has a plurality of ejection ports arranged in the Y direction for ejecting C ink. The ejection ports are also referred to as nozzles. A printing element (not shown) corresponding to each ejection port is arranged inside the plurality of ejection ports (ink flow paths) that make up the ejection port array 22. The printing elements are driven by application of a drive pulse, and generate thermal energy for ejecting C ink. The thermal energy generated by the printing elements causes bubbles to form in the C ink in the ink flow paths, thereby ejecting C ink from each ejection port. The array of printing elements corresponding to the plurality of ejection ports that make up the ejection port array 22 is referred to as a printing element array.

[0023] The sub-heater 24 is a member for heating ink. The sub-heater 24 is formed on the silicon substrate 21 using a metal material. The sub-heater 24 heats the ink near the printing elements in the ink flow path of the first heater board HB0 to a degree that prevents ink from being ejected. The sub-heater 24 is also referred to as a heating element. The temperature sensor 25 is a member for detecting temperature. The temperature sensor 25 is formed on the silicon substrate 21 using a semiconductor material. The temperature sensor 25 detects the temperature near the printing elements on the first heater board HB0. Temperature data acquired using the temperature sensor 25 is stored in the temperature value storage memory 308 (see Figure 3) of the controller 301. The temperature sensor 25 is also referred to as a detection element.

[0024] 2(b), one sub-heater 24 and one temperature sensor 25 are provided on the first heater board HB0, but this is not limiting. For example, the first heater board HB0 may be provided with multiple sub-heaters 24 and multiple temperature sensors 25. Furthermore, the number of sub-heaters 24 and the number of temperature sensors 25 may be the same or different.

[0025] As shown in FIG. 2(c), the multiple outlets (outlet numbers 1, 2, ...) that make up the outlet array 22 are divided into groups G0, G1, ... of 16 outlets each. The outlets in each group G0, G1, ... are assigned to one of 16 blocks (block numbers 0 to 15) and are driven in a time-division manner. For example, in group G0 consisting of outlets with outlet numbers 1 to 16, the outlets with outlet numbers 1 to 16 are assigned to blocks with block numbers 0 to 15 in that order. In group G1 consisting of outlets with outlet numbers 17 to 32, the outlets with outlet numbers 17 to 32 are assigned to blocks with block numbers 0 to 15 in that order.

[0026] <Recording device control system> Next, the control system of the recording apparatus 100 will be described. Fig. 3 is a block diagram showing the control system of the recording apparatus 100. As shown in Fig. 3, the recording apparatus 100 further includes a controller (ASIC) 301, a ROM 302, a DRAM 303, and an encoder sensor 304. The controller 301 includes a CPU 305, a recording data generation unit 306, a discharge timing generation unit 307, a temperature value storage memory 308, a sub-heater table storage memory 309, first to fourth data transfer units 310 to 313, and a heating control unit 320.

[0027] ROM (Read Only Memory) 302 stores various control programs, such as a program for controlling recording of recording device 100, which are executed by CPU 305. In addition to the various control programs, ROM 302 also stores fixed data necessary for various operations of recording device 100.

[0028] DRAM (Dynamic Random Access Memory) 303 is required for CPU 305 to execute programs. DRAM 303 is used as a work area for CPU 305, as a temporary storage area for various received data, and stores various setting data. Note that, although only one DRAM 303 is implemented in the example shown in FIG. 3, multiple DRAMs may be implemented. Also, both DRAM and SRAM (Static Random Access Memory) may be implemented, so that multiple memories with different access speeds are provided.

[0029] The encoder sensor 304 detects the relative positions of the first to fourth print heads 105 to 108 and the print medium P. Position information indicating the relative positions of the first to fourth print heads 105 to 108 and the print medium P detected by the encoder sensor 304 is transmitted from the encoder sensor 304 to the ejection timing generation unit 307.

[0030] A CPU (Central Processing Unit) 305 loads a program stored in a ROM 302 into a DRAM 303 and executes the program loaded into the DRAM 303. The CPU 305 executes the program loaded into the DRAM 303 to realize functional modules such as a print data generation unit 306, a discharge timing generation unit 307, data transfer units 310 to 313, and a heating control unit 320, thereby controlling the overall operation of the printing apparatus 100.

[0031] The print data generation unit 306 receives image data from a host device 500, such as a PC (Personal Computer), provided external to the printing device 100. The print data generation unit 306 performs color conversion processing, quantization processing, etc. on the received image data to generate print data for ejecting ink from the first to fourth print heads 105 to 108 to print an image on the printing medium P. The print data generated by the print data generation unit 306 is stored in the DRAM 303.

[0032] The ejection timing generation unit 307 receives position information detected by the encoder sensor 304, which indicates the relative positions of the first to fourth print heads 105 to 108 and the print medium P. Based on the received position information, the ejection timing generation unit 307 generates information indicating the timing at which each of the first to fourth print heads 105 to 108 ejects ink, i.e., so-called ejection timing information. The timing at which the first to fourth print heads 105 to 108 eject ink is referred to as the ejection timing.

[0033] The temperature value storage memory 308 stores temperature data of the first to fourth print heads 105 to 108. The temperature value storage memory 308 is electrically connected to the first to fourth data transfer units 310 to 313 via the heating control unit 320. The temperature data is, for example, output value (voltage value) data from the temperature sensor 25 indicating the temperatures of the first to fourth print heads 105 to 108. The temperature data may be data indicating temperatures such as Celsius temperature, Fahrenheit temperature, or Kelvin temperature.

[0034] The first data transfer unit 310 reads the print data stored in the DRAM 303 in accordance with the ejection timing of the first print head 105 indicated by the ejection timing information generated by the ejection timing generation unit 307. The first data transfer unit 310 generates information for driving the sub-heater 24 of the first print head 105 based on the temperature data of the first print head 105 stored in the temperature value storage memory 308. The information for driving the sub-heater 24 generated by the first to fourth data transfer units 310 to 313 is referred to as sub-heater drive information. The first data transfer unit 310 then transfers the print data read from the DRAM 303 and the generated sub-heater drive information to the first print head 105.

[0035] The second data transfer unit 311 reads the print data stored in the DRAM 303 in accordance with the ejection timing of the second print head 106 indicated by the ejection timing information generated by the ejection timing generation unit 307. The second data transfer unit 311 generates sub-heater drive information for the second print head 106 based on the temperature data of the second print head 106 stored in the temperature value storage memory 308. The second data transfer unit 311 then transfers the print data read from the DRAM 303 and the generated sub-heater drive information to the second print head 106.

[0036] The third data transfer unit 312 reads the print data stored in the DRAM 303 in accordance with the ejection timing of the third print head 107 indicated by the ejection timing information generated by the ejection timing generation unit 307. The third data transfer unit 312 generates sub-heater drive information for the third print head 107 based on the temperature data of the third print head 107 stored in the temperature value storage memory 308. The third data transfer unit 312 then transfers the print data read from the DRAM 303 and the generated sub-heater drive information to the third print head 107.

[0037] The fourth data transfer unit 313 reads the print data stored in the DRAM 303 in accordance with the ejection timing of the fourth print head 108 indicated by the ejection timing information generated by the ejection timing generation unit 307. The fourth data transfer unit 313 generates sub-heater drive information for the fourth print head 108 based on the temperature data of the fourth print head 108 stored in the temperature value storage memory 308. Then, the fourth data transfer unit 313 transfers the print data read from the DRAM 303 and the generated sub-heater drive information to the fourth print head 108.

[0038] The first to fourth printheads 105 to 108 drive their respective print elements to eject ink based on the print data transferred from the first to fourth data transfer units 310 to 313. The temperature sensors 25 on the heater boards HB0 to HB5 of the first to fourth printheads 105 to 108 output data indicating the temperatures detected by the temperature sensors 25 to the heating control unit 320. The heating control unit 320 acquires temperature data for the first to fourth printheads 105 to 108 from the data indicating the temperatures (output values) output from the temperature sensors 25. The heating control unit 320 stores the acquired temperature data in the temperature value storage memory 308, thereby updating the temperature data for the first to fourth printheads 105 to 108. The updated temperature data is used when the next sub-heater drive information is generated.

[0039] Fig. 4 is a block diagram showing part of the control system of the recording device 100. Fig. 4 schematically shows the relationship between the first recording head 105, the first data transfer unit 310, and the heating control unit 320. The second recording head 106, the third recording head 107, and the fourth recording head 108 have the same configuration as the first recording head 105, and are therefore not shown in Fig. 4. The second data transfer unit 311, the third data transfer unit 312, and the fourth data transfer unit 313 have the same configuration as the first data transfer unit 310, and are therefore not shown in Fig. 4.

[0040] The first printhead 105 further includes a logic unit 26 and an FET 27. A plurality of FETs (Field Effect Transistors) 27 are provided on each of the heater boards HB0 to HB5 in the first printhead 105, corresponding to the plurality of orifices (printing elements) that make up the orifice array 22. The FETs 27 are electrically connected to the logic unit 26 and an FET power supply circuit 327 of the heating control unit 320. The logic unit 26 is electrically connected to the first data transfer unit 310 (signal generation unit 316) and a logic power supply circuit 326 of the heating control unit 320. The logic unit 26 receives a drive control signal including print data transferred from the first data transfer unit 310, and drives the FETs 27 corresponding to the orifices (printing elements) that eject ink. As a result, the printing elements to which a drive pulse is applied via the FETs 27 generate thermal energy, allowing ink droplets to be ejected from specific orifices. Like the first printhead 105, the second printhead 106, the third printhead 107, and the fourth printhead 108 further include a logic unit 26 and an FET 27. In the following description, the drive control signals for driving the memory elements of the first to fourth printheads 105 to 108 will be simply referred to as control signals.

[0041] As described above, the temperature sensor 25 is provided on each of the heater boards HB0 to HB5 in the first to fourth print heads 105 to 108. The temperature sensor 25 is electrically connected to the temperature acquisition unit 321 of the heating control unit 320 and the constant current circuit 325. In this embodiment, the ground wiring of the circuit connected to the logic unit 26 and the ground wiring of the temperature sensor 25 are common. In other words, a portion of the line (wiring) used to transmit control signals from the controller 301 to the first to fourth print heads 105 to 108 is common to a portion of the line (wiring) electrically connected to the temperature sensor 25 in each print head.

[0042] The first data transfer unit 310 includes a signal generation unit 316 and a counter 318. The signal generation unit 316 generates transfer data to be transferred from the controller 301 to the first printhead 105 as a control signal for driving each storage element of the first printhead 105. The transfer data generated by the signal generation unit 316 includes the above-mentioned print data and sub-heater drive information. The transfer data generated by the signal generation unit 316 is digital data compatible with a serial transmission method (serial communication). The signal generation unit 316 is electrically connected to the DRAM 303, which stores the print data, via the heating control unit 320. The counter 318 counts the amount of data change Cnt within a predetermined period in the transfer data generated by the signal generation unit 316. Details of the counter 318 will be described later. Like the first data transfer unit 310, the second data transfer unit 311, the third data transfer unit 312, and the fourth data transfer unit 313 each include a signal generation unit 316 and a counter 318.

[0043] The heating control unit 320 has a temperature acquisition unit 321, a temperature correction unit 322, a constant current circuit 325, a logic power supply circuit 326, and an FET power supply circuit 327. The temperature acquisition unit 321 reads the output value from the temperature sensor 25 to acquire temperature data of the first to fourth print heads 105 to 108. The temperature correction unit 322 calculates a correction value for correcting the output value from the temperature sensor 25 based on the amount of change Cnt in the data within a predetermined period counted by the counter 318. The constant current circuit 325, the logic power supply circuit 326, and the FET power supply circuit 327 may be provided in the controller 301 independently of the heating control unit 320.

[0044] <Issues in this embodiment> Next, we will explain again the problems that may arise in this embodiment, specifically, problems that may arise when acquiring temperature data using the temperature sensors 25 of the first to fourth print heads 105 to 108. In this embodiment, diode sensors are used as the temperature sensors 25. The output from the temperature sensor 25 using a diode sensor is referred to as Di output.

[0045] FIG. 5 is a diagram showing drive blocks and temperature acquisition blocks. FIG. 5 shows one column period divided into 17 parts. One column period is also referred to as one recording period or one drive period. Of the 17 divisions of one column period, there are 16 drive blocks (time divisions) and one temperature acquisition block. In FIG. 5, the AD_ENB signal indicates a temperature acquisition block. The LAT output indicates the output of a latch signal. As an example, as shown in FIG. 2(c), a case will be described in which the multiple ejection ports constituting the ejection port array 22 are assigned to blocks numbered 0 to 15, with each block consisting of 16 ejection ports, and divided drive is performed for each block at a drive frequency of 15.6 kHz. In this case, one column period is approximately 64 μs. The period of the temperature acquisition block is approximately 3.77 μs, which is 1 / 17 of 64 μs.

[0046] FIG. 6 is an explanatory diagram illustrating a reading error of the Di output value caused by a fluctuation in VSS when a portion of the line used to transmit control signals to the first to fourth print heads 105-108 and a portion of the line electrically connected to the temperature sensor 25 are shared. FIG. 6 illustrates how the transmission of control signals to the first to fourth print heads 105-108 and the reading of the output value from the temperature sensor 25 after the control signal transmission are performed within a predetermined period. In this embodiment, VSS represents the potential at a measurement point that serves as a reference in the circuitry within the print head. In the timing chart of FIG. 6, from the top to the bottom, the timing of generation of the latch signal (H_LAT), the transmission time of the transfer data, the raw output value from the temperature sensor 25, the output value from the temperature sensor 25 after passing through a low-pass filter, and the period of the temperature acquisition block are represented. Note that the raw output value from the temperature sensor 25 is the output value from the temperature sensor 25 before passing through a low-pass filter (not shown) described below.

[0047] The transfer data latch signal (H_LAT) is generated for each block period of a driving block or temperature acquisition block. As mentioned above, the period of one block is one column period divided by the total number of driving blocks and temperature acquisition blocks. In the example shown in Figures 5 and 6, the total number of driving blocks and temperature acquisition blocks is (16 + 1 =) 17. The period of one block is approximately 3.77 [μs].

[0048] The transfer data transferred by the first to fourth data transfer units 310 to 313 are data signals (LVDS signals) included in control signals for driving the storage elements of the first to fourth printheads 105 to 108. The number of data to be transferred and the transfer clock do not depend on the drive mode, so the transfer time of the transfer data is constant regardless of the drive mode. In the example shown in Figures 5 and 6, the transfer time of the transfer data is 2.64 [μs].

[0049] During the transfer data transfer period, VSS float occurs due to the fact that the ground wiring of the circuit (logic unit 26) in the printhead and the ground wiring of the temperature sensor 25 are shared. VSS float refers to VSS being misaligned from ground (GND). After the transfer data is transmitted, the VSS fluctuation is quickly resolved. In this embodiment, a low-pass filter (not shown) is provided in the circuit in the printhead to moderate the potential fluctuation. Therefore, the output from the temperature sensor 25 (Di output) after passing through the low-pass filter takes longer to recover from the influence of VSS fluctuation than the raw output from the temperature sensor 25. The temperature acquisition unit 321 reads the Di output value in the temperature acquisition block following the drive block to which the transfer data is transferred. However, the influence of the VSS fluctuation that occurred in the drive block immediately before the temperature acquisition block remains unresolved even in the temperature acquisition block. The temperature acquisition block period refers to the entire time required to acquire the temperature data, including not only the Di output value reading but also the associated processing such as A / D conversion. The actual Di output value is read in the first half of the temperature acquisition block (see the thick arrow in Figure 6).

[0050] Figure 7 is a schematic diagram showing the change in the output (Di output) from the temperature sensor 25 in response to differences in the amount of data change in the transfer data. Because the current flowing through the circuitry in the printhead varies depending on the amount of data change in the transfer data, the amount of VSS fluctuation caused by the current flowing through the circuitry in the printhead also varies. The solid line in Figure 7 shows the Di output when the amount of data change within the transfer data time is 44, in other words, when the amount of data change is relatively large. The dashed line in Figure 7 shows the Di output when the amount of data change within the transfer data time is 22, in other words, when the amount of data change is relatively small. The arrow in Figure 7 indicates the timing (TG) at which the Di output value is read via the low-pass filter. Note that the transfer time for the transfer data is 2.64 μs, as mentioned above. The Di output is expressed as a voltage. As shown in Figure 7, if the Di output changes due to crosstalk in the control signal caused by changes in the data included in the printhead control signal, accurate temperature data for the printhead may not be obtained. In this embodiment, a configuration will be described that can obtain accurate temperature data of the printhead regardless of changes in data included in the control signal of the printhead.

[0051] <Correction amount determination process> In this embodiment, the amount of offset when acquiring temperature data, which varies depending on the amount of data change in the control signal (transfer data), is derived, and the output value (Di output value) from the temperature sensor 25 is corrected based on the derived amount of offset. To summarize the correction method, the temperature acquired by driving the print head when there is no influence from the transfer of the transfer data, i.e., when the time between the transfer of the transfer data and the acquisition of the temperature data is long, is used as the reference temperature. Then, the difference between the temperature acquired by driving the print head when the amount of data change in the transfer data is changing and the reference temperature is calculated, and the correction amount indicating the degree of correction of the Di output value is determined.

[0052] Next, the correction amount determination process in this embodiment will be described in detail with reference to Fig. 8. Fig. 8 is a flowchart showing the correction amount determination process. Note that the steps of the flowchart shown in Fig. 8 are executed by the CPU 305 executing a program stored in the ROM 302 as a computer. The correction amount determination process is started before an image is recorded on the recording medium P for the first time. The correction amount determination process may also be started when a certain period of time has passed without an image being recorded on the recording medium P.

[0053] When the correction amount determination process starts, in step S101, the CPU 305 sets the test drive mode. The test drive mode is a mode in which the interval between the latch signals (H_LAT) of the transfer data is lengthened, so that the Di output value is read after the VSS float has subsided. In the test drive mode, for example, the interval between the latch signals (H_LAT) of the transfer data is set to 58.82 μs. This lengthens the time from the transfer of the transfer data to the reading of the Di output value, eliminating the effect of VSS fluctuations on the Di output value via the low-pass filter.

[0054] Next, in step S102, the CPU 305 acquires the temperatures of the heater boards HB0 to HB5 in the test drive mode by having the temperature acquisition unit 321 read the Di output value. Here, the temperature acquired at the first heater board HB0 is referred to as T HB0 The temperature obtained by the second heater board HB1 is T HB1 The temperature obtained by the third heater board HB2 is T HB2 The temperature obtained by the fourth heater board HB3 is T HB3 The temperature obtained by the fifth heater board HB4 is T HB4 The temperature obtained by the sixth heater board HB5 is T HB5 In addition, the general term for the temperature acquired by the heater board in the test drive mode when not relying on a heater board is T HB The temperature T HB For example, the Di output value is obtained as

[0055] Next, in step S103, the CPU 305 calculates the temperatures T HB0 ~T HB5 is determined as the reference temperature of the first to sixth heater boards HB0 to HB5. Here, the reference temperature of the first heater board HB0 is determined as Trf HB0 The reference temperature of the second heater board HB1 is set as Trf HB1 The reference temperature of the third heater board HB2 is set as Trf HB2 The reference temperature of the fourth heater board HB3 is set to Trf HB3 The reference temperature of the fifth heater board HB4 is set as Trf HB4 The reference temperature of the sixth heater board HB5 is set to Trf HB5 Furthermore, the reference temperature of the heater board when not depending on a particular heater board is referred to as Trf. The reference temperature Trf is the temperature that serves as the reference when correcting the Di output value in each drive mode. In the next step S104 and thereafter, the reference temperature Trf is used to determine the amount of correction corresponding to the difference in the amount of data change in the transferred data, specifically the correction value Vtg for correcting the Di output value.

[0056] Next, in step S104, the CPU 305 sets the drive mode for recording. In the drive mode for recording, the period of one drive block or one temperature acquisition block is set to 3.77 [μs] as described above.

[0057] Next, in step S105, the CPU 305 causes the data transfer unit to transfer the first data pattern and the temperature acquisition unit 321 to read the Di output value, thereby acquiring the temperatures of the heater boards HB0 to HB5 in the recording drive mode. Here, the temperature acquired at the first heater board HB0 when the first data pattern is transferred is designated as T1. HB0 The temperature acquired by the second heater board HB1 when the first data pattern is transferred is defined as T1. HB1The temperature acquired by the third heater board HB2 when the first data pattern is transferred is defined as T1. HB2 The temperature acquired by the fourth heater board HB3 when the first data pattern is transferred is defined as T1. HB3 The temperature acquired by the fifth heater board HB4 when the first data pattern is transferred is defined as T1. HB4 The temperature acquired by the sixth heater board HB5 when the first data pattern is transferred is defined as T1. HB5 Furthermore, regardless of the heater board, the general term for the temperature acquired at the heater board when the first data pattern is transferred is T1. For example, the Di output value is acquired as the temperature T1 when the first data pattern is transferred. The first data pattern is a data pattern in which the amount of data change is large during data transfer. Data transferred by the data transfer unit is a pair of a transfer clock and a data line. The transferred data is transferred by the data transfer unit in synchronization with the transfer clock. A 64-bit data set is formed by combining 56-bit printhead drive data and an 8-bit instruction code in one data transfer by the data transfer unit. In the first data pattern, the data set is formed so that the data of each consecutive bit in the 56-bit printhead drive data is alternately arranged in the order of "1·0" or "0·1". Using such a first data pattern, the temperature T1 at the first to sixth heater boards HB0 to HB5 when the first data pattern is transferred is HB0 ~T1 HB5 is obtained.

[0058] Next, in step S106, the CPU 305 causes the data transfer unit to transfer the second data pattern and the temperature acquisition unit 321 to read the Di output value, thereby acquiring the temperatures of the first to sixth heater boards HB0 to HB5 in the recording drive mode. Here, the temperature acquired at the first heater board HB0 when the second data pattern is transferred is designated as T2 HB0 The temperature acquired by the second heater board HB1 when the second data pattern is transferred is defined as T2 HB1The temperature acquired by the third heater board HB2 when the second data pattern is transferred is defined as T2 HB2 The temperature acquired by the fourth heater board HB3 when the second data pattern is transferred is defined as T2 HB3 The temperature acquired by the fifth heater board HB4 when the second data pattern is transferred is defined as T2 HB4 The temperature acquired by the sixth heater board HB5 when the second data pattern is transferred is defined as T2 HB5 Furthermore, in cases where the heater board is not particularly dependent, the temperature acquired at the heater board when the second data pattern is transferred is referred to as T2. For example, the Di output value is acquired as the temperature T2 when the second data pattern is transferred. In the second data pattern, a data set is formed so that the data of each successive bit in the 56-bit printhead drive data is arranged in the order of "0·0" or "1·1". Using such a second data pattern, the temperature T2 at the first to sixth heater boards HB0 to HB5 when the second data pattern is transferred is HB0 ~T2 HB5 is obtained.

[0059] Then, in step S107, the CPU 305 performs a correction equation calculation process to determine a correction equation for calculating the correction value Vtg. At this time, the CPU 305 determines a correction equation for calculating the correction value Vtg from the temperature T1 acquired by the heater board when the first data pattern is transferred and the temperature T2 acquired by the heater board when the second data pattern is transferred. Details of the correction equation calculation process will be described later. For the first data pattern, the amount of data change during one block period of the drive block is 56 times. For the second data pattern 2, the amount of data change during one block period of the drive block is 1 time. A temperature correction value per data change is calculated from the temperature T1 acquired by the heater board when the first data pattern is transferred and the temperature T2 acquired by the heater board when the second data pattern is transferred.

[0060] Next, the correction equation calculation process in this embodiment will be described in detail with reference to Fig. 9. Fig. 9 is a flowchart showing the correction equation calculation process. Note that the steps of the flowchart shown in Fig. 9 are executed by the CPU 305, which functions as a computer, executing a program stored in the ROM 302.

[0061] In step S201, CPU 305 calculates the amount of offset Tbs due to fluctuations in VSS. The amount of offset Tbs due to fluctuations in VSS is calculated by subtracting the reference temperature Trf (Di output value) in a state where there is no influence of the low-pass filter (inspection driving mode) from the temperature T2 (Di output value) when the second data pattern is transferred. The equation for calculating the amount of offset Tbs due to fluctuations in VSS is expressed as Tbs=T2-Trf.

[0062] Next, in step S202, CPU 305 calculates the amount of offset based on the amount of change in data. The difference between T1 and T2 is divided by the difference Dbt between the amount of change in data in the first data set and the amount of change in data in the second data set to calculate the amount of offset dT per amount of change in data. The equation for calculating the amount of offset dT per amount of change in data is expressed as dT=(T1-T2) / Dbt.

[0063] Then, in step S203, the CPU 305 determines a correction formula for calculating the correction value Vtg based on the amount of offset Tbs due to the fluctuation of VSS and the amount of offset dT per one data change. The correction formula for calculating the correction value Vtg is expressed as Vtg=Tbs+dT×Cnt, where Cnt represents the amount of change in data at the timing of correction. The correction formula for calculating the correction value Vtg is a correction formula that represents a linear function of the amount of change Cnt in data.

[0064] <Control method when acquiring temperature data> Next, a control method for the recording device 100 that acquires temperature data using the above-mentioned correction formula when recording an image will be described. Fig. 10 is a flowchart that outlines the control method for the recording device 100. Note that the CPU 305, which functions as a computer, executes a program stored in the ROM 302, thereby executing each step of the flowchart shown in Fig. 10.

[0065] In step S301, the print data generation unit 306 generates the print data described above. At this time, the print data generation unit 306 generates the print data by performing color conversion processing, quantization processing, etc. on image data received from the host device 500. The print data generated by the print data generation unit 306 is stored in the DRAM 303.

[0066] In step S302, the ejection timing generation unit 307 generates ejection timing information indicating the timing at which ink is ejected from each of the first to fourth print heads 105 to 108. At this time, the ejection timing generation unit 307 generates the ejection timing information based on the position information received from the encoder sensor 304.

[0067] In step S303, the signal generation units 316 of the first to fourth data transfer units 310 to 313 generate transfer data to be transferred from the controller 301 to each printhead as a control signal for driving each memory element of the first to fourth printheads 105 to 108. When the signal generation unit 316 generates the transfer data, the counter 318 counts the amount of data change Cnt in the transfer data generated by the signal generation unit 316 within a predetermined period. The predetermined period is the period of one drive block, in other words, the interval of one cycle in which the latch signal (H_LAT) is output. The control signals for the first to fourth printheads 105 to 108 are digital signals containing the transfer data. The counter 318 counts each change in the signal level of the transfer data in the control signal from low to high and from high to low as one change. The data of the change amount Cnt of the data within the predetermined period counted by the counter 318 is transmitted to the temperature correction unit 322 of the heating control unit 320. The change amount Cnt of the data within the predetermined period is updated every time the latch signal (H_LAT) is output.

[0068] FIG. 11 is an explanatory diagram illustrating a specific example in which the counter 318 counts the data change amount Cnt. As shown in FIG. 11, the counter 318 receives a data transfer clock and transfer data. The counter 318 generates a first signal DT1 indicating the signal level of the transfer data when the data transfer clock signal rises, and a second signal DT2 that is shifted by one clock cycle from the first signal DT1. When the data transfer clock signal rises, if the first signal DT1 is at a high level and the second signal DT2 is at a low level, a change in signal level E(rise) from a low level to a high level can be detected. When the data transfer clock signal rises, if the first signal DT1 is at a low level and the second signal DT2 is at a high level, a change in signal level E(fall) from a high level to a low level can be detected. The counter 318 detects a change E (rise) in signal level from low level to high level and a change E (fall) in signal level from high level to low level during the valid period between latch signals (H_LAT). This allows the counter 318 to count the amount of change Cnt in data within a predetermined period (valid period). When the valid period between latch signals (H_LAT) ends, the count by the counter 318 is cleared.

[0069] 10, in step S304, the first to fourth data transfer units 310 to 313 transfer the transfer data generated by the signal generation unit 316 to the first to fourth print heads 105 to 108. When the first to fourth data transfer units 310 to 313 transfer the transfer data, the temperature acquisition unit 321 of the heating control unit 320 reads the output value (Di output value) from the temperature sensor 25. As described above, the temperature acquisition unit 321 reads the Di output value in the temperature acquisition block next to the drive block to which the transfer data is transferred.

[0070] Next, in step S305, the temperature correction unit 322 of the heating control unit 320 calculates a correction value Vtg for correcting the output value (Di output value) from the temperature sensor 25 based on the amount of change Cnt in the data within the predetermined period counted by the counter 318. At this time, the temperature correction unit 322 calculates the correction value Vtg from the amount of change Cnt in the data within the predetermined period using a correction formula that represents a linear function of the amount of change Cnt in the data within the predetermined period. Then, the temperature acquisition unit 321 acquires temperature data based on the corrected output value obtained by subtracting the correction value Vtg from the Di output value.

[0071] For example, if Tbs=4.50 [mV] and dT=0.25 [mV] are calculated in the correction amount determination process and correction formula calculation process, the correction value Vtg when Cnt=22 is (4.50 + 0.25 × 22 =) 10 [mV]. If the output value (Di output value) from temperature sensor 25 at this time is 680 [mV], the corrected output value will be (680 - 10 =) 670 [mV].

[0072] The heating control unit 320 stores the temperature data acquired by the temperature acquisition unit 321 in the temperature value storage memory 308. The sub-heaters (heating elements) 24 of the first to fourth print heads 105 to 108 heat the ink to a degree that does not cause it to be ejected, based on the sub-heater drive information transferred from the first to fourth data transfer units 310 to 313. At this time, the sub-heaters 24 heat the ink according to the temperature data acquired by the temperature acquisition unit 321 and stored in the temperature value storage memory 308.

[0073] The Di output value is corrected each time the temperature acquisition unit 321 reads the Di output value. The Di output value of the first printhead 105 is corrected based on the amount of data change Cnt within a predetermined period counted by the counter 318 of the first data transfer unit 310. The Di output value of the second printhead 106 is corrected based on the amount of data change Cnt within a predetermined period counted by the counter 318 of the second data transfer unit 311. The Di output value of the third printhead 107 is corrected based on the amount of data change Cnt within a predetermined period counted by the counter 318 of the third data transfer unit 312. The Di output value of the fourth printhead 108 is corrected based on the amount of data change Cnt within a predetermined period counted by the counter 318 of the fourth data transfer unit 313. This makes it possible to determine correction values ​​for correcting the Di output values ​​of each of the first through fourth printheads 105 through 108, thereby enabling accurate temperature data to be acquired for each printhead. Furthermore, even if the time from the transfer of data to each printhead to the reading of the Di output value is short, as in the print drive mode, accurate temperature data for each printhead can be obtained.

[0074] As described above, this embodiment makes it possible to acquire accurate temperature data of the printhead, regardless of changes in the data included in the printhead control signal. Specifically, in this embodiment, the counter 318 counts the amount of data change Cnt within a predetermined period in the control signal transmitted from the controller 301. The temperature correction unit 322 calculates a correction value Vtg for correcting the output value from the temperature sensor 25 based on the amount of data change Cnt within the predetermined period counted by the counter 318. The temperature acquisition unit 321 then acquires temperature data based on the corrected output value obtained by subtracting the correction value Vtg from the output value from the temperature sensor 25. This allows an accurate correction value Vtg to be calculated based on the amount of data change Cnt within the predetermined period in the control signal transmitted from the controller 301. Therefore, accurate temperature data of the printhead can be acquired by correcting the output value from the temperature sensor 25 based on the accurate correction value Vtg calculated based on the amount of data change Cnt. In this way, accurate temperature data of the printhead can be acquired, regardless of changes in the data included in the printhead control signal.

[0075] In the above-described embodiment, one print drive mode is set, but this is not limiting. For example, multiple print drive modes with different print element drive cycles may be set. In this case, the correction amount determination process and correction formula calculation process described above may determine a correction formula for calculating the correction value Vtg for correcting the Di output value for each of the multiple print drive modes. This makes it possible to obtain accurate print head temperature data regardless of drive conditions (print drive modes) with different print element drive cycles.

[0076] In the above-described embodiment, the first to fourth print heads 105 to 108 are so-called full-line print heads that can eject ink across the entire width of the print medium P without moving in the main scanning direction, but the present invention is not limited to this. The first to fourth print heads may also be so-called serial print heads that eject ink while moving in the main scanning direction.

[0077] In the above-described embodiment, the recording device 100 is provided with first to fourth recording heads 105 to 108 corresponding to four types (four colors) of ink, but this is not limited to this. For example, the recording device may be provided with three recording heads corresponding to three types of ink, or five recording heads corresponding to five types of ink. In this way, the recording device can be provided with multiple recording heads corresponding to multiple types of ink.

[0078] <<Other embodiments>> The present invention can also be realized by supplying a program that realizes one or more functions of the above-described embodiments to a system or device via a network or a storage medium, and having one or more processors in the computer of the system or device read and execute the program.The present invention can also be realized by a circuit (e.g., ASIC) that realizes one or more functions.

[0079] The disclosure of the present embodiment includes configurations typified by the following recording device example, recording device control method example, and program example.

[0080] <Configuration 1> A printing apparatus comprising: an element substrate on which printing elements that generate thermal energy for ejecting ink are provided; a printhead having a temperature sensor that is provided on the element substrate and detects temperature; a controller that transmits a control signal to the printhead for driving the printing elements; and a temperature acquisition unit that reads an output value from the temperature sensor when a control signal is transmitted from the controller to acquire temperature data, a part of a line used for transmitting a control signal from the controller to the printhead and a part of a line electrically connected to the temperature sensor in the printhead are common to each other; a counter that counts the amount of change in data in a control signal transmitted from the controller within a predetermined period; a temperature correction unit that calculates a correction value for correcting the output value from the temperature sensor based on the amount of change in data counted by the counter within the predetermined period; A recording device comprising:

[0081] <Configuration 2> 2. The recording device according to configuration 1, wherein the temperature acquisition unit acquires temperature data based on a corrected output value obtained by subtracting the correction value determined by the temperature correction unit from the output value of the temperature sensor.

[0082] <Configuration 3> the controller has a signal generating unit that generates a control signal to be transmitted from the controller; 3. The recording device according to claim 1, wherein the counter counts changes in data within the predetermined period when the signal generating unit generates a control signal.

[0083] <Configuration 4> the control signal transmitted from the controller is a digital signal; 4. The recording device according to any one of configurations 1 to 3, wherein the counter counts the amount of change in data within the predetermined period by detecting a change in the signal level of the control signal transmitted from the controller.

[0084] <Configuration 5> 5. The printing apparatus according to any one of configurations 1 to 4, wherein the print head has a heating element provided on the element substrate, the heating element heating ink in accordance with the temperature data acquired by the temperature acquisition unit.

[0085] <Configuration 6> 6. The recording device according to any one of configurations 1 to 5, wherein the temperature correction unit calculates the correction value using a correction formula that indicates a linear function of the amount of change in data within the predetermined period.

[0086] <Configuration 7> 7. The recording device according to any one of configurations 1 to 6, wherein a diode sensor is used as the temperature sensor.

[0087] <Configuration 8> 8. The printing apparatus according to any one of configurations 1 to 7, wherein a plurality of the printing elements are provided on the element substrate in correspondence with a plurality of ejection ports for ejecting ink.

[0088] <Configuration 9> 9. The recording apparatus according to any one of configurations 1 to 8, comprising a plurality of the recording heads provided corresponding to a plurality of types of ink.

[0089] <Configuration 10> A control method for a printing apparatus comprising: an element substrate on which printing elements that generate thermal energy for ejecting ink are provided; a printhead having a temperature sensor provided on the element substrate and that detects temperature; a controller that transmits a control signal to the printhead for driving the printing elements; and a temperature acquisition unit that reads an output value from the temperature sensor when a control signal is transmitted from the controller to acquire temperature data, a part of a line used for transmitting a control signal from the controller to the printhead and a part of a line electrically connected to the temperature sensor in the printhead are common to each other; Counting the amount of change in data in a control signal transmitted from the controller within a predetermined period; determining a correction value for correcting the output value from the temperature sensor based on the amount of change in the counted data within the predetermined period; 10. A method for controlling a recording apparatus, comprising:

[0090] <Configuration 11> 11. A program for causing a computer to execute the recording device control method according to claim 10. [Explanation of symbols]

[0091] 25 Temperature Sensor 100 Recording device 105 First recording head 106 Second recording head 107 Third recording head 108 Fourth recording head 301 Controller 318 Counter 321 Temperature acquisition section 322 Temperature correction section HB0 First heater board HB1 Second Heater Board HB2 Third Heater Board HB3 4th Heater Board HB4 5th Heater Board HB5 6th Heater Board

Claims

1. A printing apparatus comprising: an element substrate on which printing elements that generate thermal energy for ejecting ink are provided; a printhead having a temperature sensor that is provided on the element substrate and detects temperature; a controller that transmits a control signal to the printhead for driving the printing elements; and a temperature acquisition unit that reads an output value from the temperature sensor when a control signal is transmitted from the controller to acquire temperature data, a part of a line used for transmitting a control signal from the controller to the printhead and a part of a line electrically connected to the temperature sensor in the printhead are common to each other; a counter that counts the amount of change in data in a control signal transmitted from the controller within a predetermined period; a temperature correction unit that calculates a correction value for correcting the output value from the temperature sensor based on the amount of change in data counted by the counter within the predetermined period; A recording device comprising:

2. 2. The recording apparatus according to claim 1, wherein the temperature acquisition section acquires temperature data based on a corrected output value obtained by subtracting the correction value determined by the temperature correction section from the output value of the temperature sensor.

3. the controller has a signal generating unit that generates a control signal to be transmitted from the controller; The recording device according to claim 1 , wherein the counter counts changes in data within the predetermined period when the control signal is generated by the signal generating section.

4. the control signal transmitted from the controller is a digital signal; 2. The recording apparatus according to claim 1, wherein the counter counts the amount of change in data within the predetermined period by detecting a change in the signal level of the control signal transmitted from the controller.

5. 2. The printing apparatus according to claim 1, wherein the printhead has a heating element provided on the element substrate, the heating element heating ink in accordance with the temperature data acquired by the temperature acquisition unit.

6. 2. The recording apparatus according to claim 1, wherein the temperature correction section determines the correction value using a correction formula that represents a linear function of the amount of change in data within the predetermined period.

7. 2. The recording apparatus according to claim 1, wherein the temperature sensor is a diode sensor.

8. 2. The printing apparatus according to claim 1, wherein a plurality of the printing elements are provided on the element substrate in correspondence with a plurality of ejection ports for ejecting ink.

9. 2. The recording apparatus according to claim 1, further comprising a plurality of said recording heads provided corresponding to a plurality of types of ink.

10. A control method for a printing apparatus including: an element substrate on which printing elements that generate thermal energy for ejecting ink are provided; a printhead having a temperature sensor provided on the element substrate and that detects temperature; a controller that transmits a control signal to the printhead for driving the printing elements; and a temperature acquisition unit that reads an output value from the temperature sensor when a control signal is transmitted from the controller to acquire temperature data, a part of a line used for transmitting a control signal from the controller to the printhead and a part of a line electrically connected to the temperature sensor in the printhead are common to each other; Counting the amount of change in data in a control signal transmitted from the controller within a predetermined period; determining a correction value for correcting the output value from the temperature sensor based on the amount of change in the counted data within the predetermined period; 10. A method for controlling a recording apparatus, comprising:

11. A program for causing a computer to execute the recording apparatus control method according to claim 10.

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