Recording device and program

Abstract

To provide a technique which is advantageous in relatively easily realizing proper discharge inspection in an inkjet recording device.SOLUTION: A recording device includes a plurality of nozzles that perform recording by discharging ink. The recording device comprises: a plurality of heating elements which is provided in correspondence with the plurality of nozzles, and which respectively heats ink and causes the ink to be discharged from a corresponding nozzle; a plurality of temperature detecting elements provided in correspondence with the plurality of heating elements; inspection means for inspecting a discharge mode of ink from the nozzles based on signals from the plurality of temperature detecting elements; and signal generating means for generating a clock signal. The recording device includes as operation modes: a recording mode in which recording is performed by the plurality of heating elements without conducting inspection by the inspection means; and an inspection mode in which inspection is conducted by the inspection means based on recording performed by the plurality of heating elements. In the inspection mode, the signal generating means generates a clock signal in a mode that is different from a mode in the recording mode.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates primarily to a recording device. [Background technology]

[0002] Among recording devices such as inkjet printers, there are some that perform ejection inspection by evaluating the state of ink ejection from nozzles, as shown in Patent Document 1. According to Patent Document 1, a heating element and a temperature detection element are provided corresponding to the nozzle, and this ejection inspection is performed based on the result of the first-order differentiation of the signal waveform of the temperature detection element when the heating element is driven. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2008-000914 A Summary of the Invention [Problem to be solved by the invention]

[0004] In general, clock signals are used to control the operation of electronic devices in order to perform synchronous control between elements, and this is also the case for the operation of the heating elements and temperature detection elements of the recording device. However, the clock signals can introduce noise, which can hinder the realization of proper ejection testing.

[0005] The present invention was made in response to the inventor's recognition of the above-mentioned problems, and an exemplary object of the present invention is to provide a technique that is advantageous for relatively easily realizing appropriate ejection inspection in an inkjet recording apparatus. [Means for solving the problem]

[0006] One aspect of the present invention relates to a recording device, the recording device comprising: A recording device having a plurality of nozzles for performing recording by ejecting ink, a plurality of heating elements provided corresponding to the plurality of nozzles, each heating element heating ink to cause the ink to be ejected from a corresponding nozzle; A plurality of temperature detection elements provided corresponding to the plurality of heating elements; an inspection means for inspecting the state of ink ejection from the nozzles based on signals from the plurality of temperature detection elements; A signal generating means for generating a clock signal, as operation modes, a recording mode in which recording is performed by the plurality of heating elements without performing an inspection by the inspection means, and an inspection mode in which inspection is performed by the inspection means based on the recording performed by the plurality of heating elements, In the inspection mode, the signal generating means generates a clock signal in a manner different from that in the recording mode. It is characterized by: Effect of the Invention

[0007] According to the present invention, it is possible to realize appropriate ejection inspection. [Brief description of the drawings]

[0008] [Figure 1] FIG. 2 is a perspective view showing an example of a portion of the internal structure of a recording apparatus. [Diagram 2] FIG. 2 is a system block diagram illustrating a control system of the printing apparatus. [Diagram 3] FIG. 2 is a schematic diagram showing an example of the structure of an element substrate. [Figure 4] FIG. 2 is a diagram showing an example of the configuration of an element substrate. [Diagram 5] FIG. 4 is a diagram showing the connection relationship between the print engine unit and the element substrate. [Figure 6] FIG. 4 is a diagram showing an example of the configuration of an inspection circuit. [Figure 7] FIG. 4 is a diagram showing an example of the configuration of a signal processing / determination unit. [Figure 8] 6A and 6B are diagrams showing output results of a temperature detection element when a printing element is driven. [Figure 9] FIG. 2 is a diagram showing a part of a transfer circuit that transfers a clock signal. [Figure 10] 6A and 6B are diagrams showing output results of a temperature detection element when a printing element is driven. [Figure 11] 11 is a flowchart showing an example of a method for performing a discharge inspection. [Figure 12] 6A and 6B are diagrams showing output results of a temperature detection element when a printing element is driven. [Figure 13] 6A and 6B are diagrams showing output results of a temperature detection element when a printing element is driven. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, the embodiments will be described in detail with reference to the attached drawings. Note that the following embodiments do not limit the invention according to the claims. Although the embodiments describe a number of features, not all of these features are essential to the invention, and the features may be combined in any manner. Furthermore, in the attached drawings, the same reference numbers are used for the same or similar configurations, and duplicated descriptions are omitted.

[0010] <Example of recording device configuration> 1 shows an example of a portion of the internal structure of a recording device 1000 according to an embodiment. In this embodiment, the recording device 1000 includes a recording head 3 capable of performing recording at once across the entire width of a recording medium 2. Such a recording head 3 may also be expressed as a line head, a full line head, or the like.

[0011] The recording device 1000 further includes a transport unit 1 that transports the recording medium 2 in a predetermined direction, and the recording head 3 extends in a direction intersecting (substantially perpendicular to) the transport direction of the recording medium 2. The transport unit 1 includes two transport rollers 81 and 82 that are arranged at a distance F apart in the transport direction of the recording medium 2, and transports the recording medium 2 by rotating them.

[0012] The recording head 3 has a plurality of nozzles (ejection ports) arranged in the extension direction, and can eject ink (or liquid) from each nozzle. The recording head 3 is an inkjet type head that ejects ink using thermal energy, and has a plurality of recording elements built in corresponding to the plurality of nozzles. In this example, each recording element is an electrothermal conversion element, a heating element, or simply a heater, and is energized by applying a pulse voltage based on a recording signal to a corresponding switch element to heat the ink, thereby ejecting the ink from the corresponding nozzle.

[0013] The recording head 3 is provided with a negative pressure control unit 230 that controls the pressure (negative pressure) in the ink path, a liquid supply unit 220 that communicates with the negative pressure control unit 230, and a liquid connection part 111 that serves as an ink supply port / discharge port for the liquid supply unit 220. The negative pressure control unit 230, the liquid supply unit 220, and the liquid connection part 111 can be housed and fixed in a predetermined housing 80.

[0014] In such a configuration, the print head 3 performs printing on the print medium 2 that is continuously or intermittently conveyed by the conveyance section 1. Such a printing apparatus 1000 can also be expressed as a line-type printing apparatus.

[0015] The recording head 3 is configured to support color printing and is capable of ejecting cyan (C), magenta (M), yellow (Y) and black (K) inks. The liquid supply unit 220 forms supply paths capable of supplying each type of ink to the recording head 3, and the recording head 3 is connected to an ink tank via the supply paths. In addition, the recording head 3 is electrically connected to an electrical control unit (not shown) for supplying signals (recording signals) for controlling the ejection of ink and supplying power from a power source.

[0016] The recording device 1000 is not limited to the above-mentioned line type recording device, and other known configurations may be adopted. For example, the recording device 1000 may be a serial type recording device that records on the recording medium 2 while reciprocating / scanning the recording head 3 by a carriage in a direction intersecting the transport direction of the recording medium 2. Such a recording head 3 may also be expressed as a serial head, etc.

[0017] The recording medium 2 is typically a paper material, but may be other sheet-like materials. The recording medium 2 may be a cut sheet cut to a predetermined size, or a roll sheet formed by winding up a long sheet.

[0018] <Example of a recording device system configuration> 2 is a system block diagram for explaining a control system of the recording device 1000. The recording device 1000 further includes a controller unit 410 and a print engine unit 417. In this embodiment, the recording device 1000 is a multifunction peripheral (MFP) that further includes a scan function, and further includes a scanner engine unit 411.

[0019] The controller unit 410 can include a main controller 401, a host IF 402, a wireless IF 403, an operation panel 404, a print engine IF 405, a RAM 406, a ROM 407, an image processing unit 408, and a scanner engine IF 409. In this specification, IF refers to an interface for realizing the exchange of signals with external elements (input / output or transmission / reception).

[0020] The main controller 401 performs predetermined arithmetic processing based on an operation input on an operation panel 404 and / or based on a print job input from the host device 400 via a host IF 402 or a wireless IF 403. For example, the main controller 401 executes a target program using a RAM 406 and a ROM 407, and performs image processing on image data included in the print job using an image processing unit 408.

[0021] A touch panel display or the like is typically used for the operation panel 404, which accepts operation input from the user and displays necessary information to the user. Instead of the operation panel 404, an operation input unit that accepts operation input and a display unit that displays necessary information may be provided separately, that is, the operation input unit and the display unit may be provided integrally or separately.

[0022] The input of a print job from the host device 400 to the recording device 1000 may be realized via wireless communication or wired communication, or may be realized by reading from an external storage device connected to the recording device 1000. A known communication method may be used for wireless communication or wired communication. For example, examples of communication methods using wireless communication include Wi-Fi (Wireless Fidelity (registered trademark)) and Bluetooth (registered trademark). Also, examples of communication methods using wired communication include USB (Universal Serial Bus).

[0023] The print engine IF 405 exchanges signals with a print engine unit 417. The scanner engine IF 409 exchanges signals with a scanner engine unit 411.

[0024] In this manner, the controller unit 410 performs drive control for the entire system of the printing apparatus 1000.

[0025] The print engine unit 417 may include a controller IF 418, a print controller 419, a ROM (Read Only Memory) 420, and a RAM (Random Access Memory) 421. The print engine unit 417 may further include an image processing controller 422, a maintenance control unit 423, an ink supply control unit 424, a head carriage control unit 425, a transport control unit 426, and a head IF 427.

[0026] The controller IF 418 exchanges signals with the controller unit 410. The print controller 419 executes a target program using the ROM 420 and RAM 421, thereby performing signal processing required for executing recording. For example, image data and commands based on a print job received via the controller IF 418 are stored in the RAM 421. Based on instructions from the print controller 419, the image processing controller 422 converts the image data into recording data so that the recording head 3 can handle the image data, and stores the converted data in the RAM 421.

[0027] The maintenance control unit 423 can control the maintenance operation of the recording head 3, and controls the driving of a cap unit and a wiping unit, which are maintenance units not shown. The ink supply control unit 424 controls the driving of the liquid supply unit 220 so that the pressure of the ink supplied to the recording head 3 is within a reference range. The head carriage control unit 425 can change the orientation and position of the recording head 3 depending on the operating state (e.g., recording state, maintenance state, etc.) of the recording device 1000. The transport control unit 426 controls the transport of the recording medium 2 by controlling the driving of the transport rollers 81 and 82. The head IF 427 exchanges signals with the recording head 3.

[0028] In this manner, the print engine unit 417 controls the driving of the printing section including the print head 3 .

[0029] The scanner engine unit 411 may include a RAM 412, a transport control unit 413, a controller IF 414, a scanner controller 415, and a sensor 416. When executing a scan function, the scanner controller 415 causes the transport control unit 413 to scan a target document (a sheet member on which an image is formed) with the sensor 416, thereby acquiring image data and storing it in the RAM 412. A known optical sensor such as a CCD / CMOS image sensor may typically be used as the sensor 416. The controller IF 414 exchanges signals with the controller unit 410.

[0030] In this way, the scanner engine unit 411 controls the driving of a scanner section (not shown), and the controller unit 410 is also capable of outputting the acquired image data to the print engine unit 417 .

[0031] The controllers 401, 415 and / or 419 are CPUs (central processing units) that perform calculations to control the drive of the corresponding elements, and may be MPUs (microprocessor units) with accompanying memory, or simply processors, etc.

[0032] <Configuration of element substrate having recording elements> Fig. 3(a) is a perspective view of an element substrate 101 built into the print head 3, and Fig. 3(b) is a schematic cross-sectional view of the element substrate 101 taken along the cutting plane a-a'. The element substrate 101 includes a plurality of nozzles 1204, a plurality of corresponding print elements 104, and a corresponding temperature detection element 107. The element substrate 101 is formed by fixing a nozzle plate provided with the nozzles 1204 to a multilayer structure 113 including a semiconductor substrate and a wiring structure, and a plurality of terminals 1205 can be arranged on the side of the nozzle plate. The element substrate 5 may be expressed as a print element substrate, a nozzle substrate, or the like.

[0033] 3(b), each recording element 104 is located above a corresponding temperature detection element 107, and when viewed in the up-down direction, the temperature detection element 107 is arranged to overlap the recording element 104. The recording element 104 is connected to predetermined wiring portions via contact plugs at both ends, and becomes conductive when the corresponding switch element is brought into a conductive state. Similarly, the temperature detection element 107 is connected at both ends to other wiring portions via contact plugs, and is capable of detecting the temperature generated by the passage of current through the recording element 104. Specifically, a constant current is supplied to the temperature detection element 107, which enables a potential difference corresponding to the temperature to be generated, and this potential difference can be output as a detection signal. The nozzles 1204 are positioned above the corresponding printing elements 104 , and ink heated by energizing the printing elements 104 is ejected from the nozzles 1204 .

[0034] 4 shows an example of the configuration of the element substrate 101. The element substrate 101 further includes a data input circuit 102, a printing element selection circuit 103, a temperature detection element selection circuit 106, a constant current power supply 112, and an inspection circuit 201. Each printing element 104 forms a single segment together with a corresponding temperature detection element 107, and n segments seg0 to segn are shown, where n is an arbitrary integer. Each segment (for example, segment seg0) includes the printing element 104 and the temperature detection element 107, as well as switch elements 105, 108, 109, and 110.

[0035] The switch element 105 is a drive switch connected in series to the recording element 104 so as to energize the recording element 104. Each drive switch 105 can be controlled by the recording element selection circuit 103, and in this example, the drive switches 105 of segments seg0 to segn are controlled by signals h0 to hn, respectively.

[0036] The switch element 108 is a selection switch for connecting the constant current power supply 112 to one of the temperature detection elements 107 selected from the plurality of temperature detection elements 107 to supply a constant current. Each selection switch 108 can be controlled by the temperature detection element selection circuit 106, and in this example, the selection switches 108 for the segments seg0 to segn are controlled by signals s0 to sn, respectively. The switch elements 109 and 110 are read switches for reading out a potential difference generated in the temperature detection element 107 by the supply of a constant current as a detection signal via a predetermined signal line (indicated by "p" and "n" in the figure). The read-out detection signal is input to the inspection circuit 201.

[0037] The data input circuit 102 generates a latch signal l_lt, clock signals clk_h and clk_s, data signals d_h and d_s, and a heat enable signal he. The recording element selection circuit 103 receives the latch signal l_lt, the clock signal clk_h, the data signal d_h, and the heat enable signal he, and based on these, the recording element selection circuit 103 controls the driving of the switch element 105. The temperature detection element selection circuit 106 receives the latch signal l_lt, the clock signal clk_s, and the data signal d_s, and based on these, the temperature detection element selection circuit 106 controls the driving of the switch elements 108 to 110. The latch signal l_lt, the clock signal clk_s, and the data signal d_s are further input to the inspection circuit 201, the details of which will be described later.

[0038] As shown in FIG. 5, each of the above signals may be generated based on the corresponding one of the latch signal LT, the clock signal CLK, and the data signal D received from the print engine unit 417. For example, the latch signal l_lt may be generated based on the latch signal LT, and the clock signals clk_h and clk_s may be generated based on the clock signal CLK, with the frequency and cycle adjusted for the internal circuit. The data signals d_h and d_s and the heat enable signal he may be generated based on the data signal D. The data signal d_h is used to select the recording element 104 to be driven, and the heat enable signal he is used to actually drive the selected recording element 104. The data signal d_s may be used to select the corresponding temperature detection element 107. The element substrate 101 is further supplied with a clock signal CLK2, and the determination result signal Do, which is output data from the inspection circuit 201, is transferred to the print engine unit 417 based on the clock signal CLK2, as will be described in detail later. Signals are exchanged between the print engine unit 417 and the element substrate 101 via a terminal 1205 .

[0039] In such a configuration of the element substrate 101, the number of the recording elements 104 can be increased to increase the recording speed. On the other hand, when all of the multiple recording elements 104 are driven at once, noise (potential fluctuation) due to the generation of a large current may occur. To prevent such noise, a method may be typically adopted in which the multiple recording elements 104 are divided into two or more groups and two or more recording elements 104 in each group are driven in sequence. The recording elements 104 that are driven approximately simultaneously between groups may be expressed as a block. Such a driving method is also called a time-division driving method (or simply a time-division method), the group is also called a time-division group, and the block is also called a time-division block.

[0040] 4 again, in this example, the recording elements 104 of seg0, seg8, seg16, etc. among the segments seg0 to segn are assigned to the first block. The recording elements 104 of seg1, seg9, seg17, etc. are assigned to the second block, and similarly, the recording elements 104 of the other segments are assigned to the third to eighth blocks. By driving the first to eighth blocks assigned in this way in order in block units, recording in a time-division manner is realized. The recording element selection circuit 103 typically includes a shift register and a decoder so as to realize such time-division driving, and performs the above-mentioned drive control of the recording elements 104 based on the signals l_lt, clk_h, d_h, and he from the data input circuit 102.

[0041] The temperature detection element selection circuit 106 selects the temperature detection element 107 corresponding to the printing element 104 driven as described above based on the signals l_lt, clk_s, and d_s from the data input circuit 102, and controls its driving. That is, a constant current is supplied to the corresponding temperature detection element 107 via the switch element 108, and the potential difference generated by the selection is read as a detection signal via the switch elements 109-110 and input to the inspection circuit 201. The inspection circuit 201 performs a discharge inspection, which will be described later, based on the detection signal, and inspects whether the ink discharge state of the corresponding nozzle 1204 satisfies a standard (whether it is appropriate or not, whether the discharge is normal or difficult). A signal instructing the execution of such temperature detection is, for example, included in the data signal D as identification information indicating whether or not to perform drive control of the temperature detection element 107 when driving the printing element 104, and corresponds to the data signal d_s in this example.

[0042] With this configuration, the recording device 1000 includes, as operation modes, a recording mode in which recording is performed without performing a discharge inspection, and an inspection mode in which recording for a discharge inspection is performed and a discharge inspection is performed based on the recording, and can perform appropriate recording. As an example, in the inspection mode, a discharge inspection is performed by controlling the driving of the temperature detection element 107, and in the recording mode, recording can be performed using print data corrected based on the results of the discharge inspection. Note that the correction is typically performed by the print controller 419 of the print engine unit 417, but may also be performed by the controller unit 410.

[0043] <Inspection circuit configuration> 6 is a block diagram showing an example of the configuration of the inspection circuit 201. The inspection circuit 201 includes an inspection start signal generating unit 202, a mask signal generating unit 203, a judgment data holding unit 204, an output unit 205, and a signal processing / judging unit 301.

[0044] The detection start signal generating unit 202 generates a detection start signal lt_s indicating the timing to start temperature detection (measurement) by the temperature detection element 107 based on the latch signal l_lt and the clock signal clk_s. The mask signal generating unit 203 receives the detection start signal lt_s from the detection start signal generating unit 202 and generates a mask signal m having a predetermined time width. The signal processing / judgment unit 301 receives a detection signal from the temperature detection element 107 via a signal line ("p" and "n" in the figure) and judges whether the ink ejection state of the corresponding nozzle 1204 meets a standard based on the signal waveform (temperature waveform). If the corresponding nozzle 1204 is not ejecting normally (if ejection is difficult), the signal processing / judgment unit 301 outputs a binary signal cmp to the judgment data holding unit 204. The judgment data holding unit 204 converts the binary signal cmp to a signal d based on the mask signal m and the detection start signal lt_s and outputs it to the output unit 205.

[0045] 7 is a block diagram showing an example of the configuration of the signal processing / determination unit 301. As described above, the signal processing / determination unit 301 is capable of outputting the binarized signal cmp, and in this example, includes a differential amplifier circuit 302, a filter circuit 303, a binarization unit 304, and an adjustment unit 305.

[0046] The detection signal of the temperature detection element 107 (potential difference generated in the temperature detection element 107) is amplified by a differential amplifier circuit 302 and output as an output dif to a filter circuit 303, and is then differentially processed (dT / dt) to output as a filter output fo to a binarization unit 304. A comparator is typically used for the binarization unit 304, which compares the filter output fo with a predetermined threshold th set by an adjustment unit 305 to generate a binarized signal cmp. The threshold th is set as a reference value for determining whether or not the nozzle 1204 to be inspected has properly ejected ink, and is also expressed as an ejection inspection threshold or an ejection inspection threshold voltage.

[0047] The adjustment unit 305 includes a DA converter that generates the threshold value th to be provided to the binarization unit 404, and may also include, for example, a DA converter that generates a current Iref to be provided to the constant current power supply 112. These DA converters generate signals based on the latch signal l_lt, the clock signal clk_s, and the data signal d_s.

[0048] <How to judge the discharge state> 8 shows the signal waveform (temperature waveform) output from the temperature detection element 107 when a drive pulse (pulse-shaped drive signal) 701 is applied to the recording element 104 as sensor temperature T, and also shows its differential value, the filter output fo, as temperature change signal dT / dt. In the figure, the sensor temperature T is shown as temperature (unit [°C]), but in reality it is detected by a potential difference (unit [V]) generated by supplying a constant current to the temperature detection element 107. In other words, the sensor temperature T is obtained by converting the detected potential difference. The temperature change signal dT / dt is shown as a change over time in the detected potential difference (unit [mV / sec]).

[0049] Waveform 703 shows the change in sensor temperature T in the case of normal ejection. In the process in which sensor temperature T rises and then falls based on the supply of heat enable signal he, in the case of normal ejection, a characteristic point 704 appears due to cooling caused by the tail of an ink droplet ejected from nozzle 1204 returning into nozzle 1204. According to waveform 703, after characteristic point 704, sensor temperature T drops rapidly. On the other hand, in the case of difficulty in ejection, characteristic point 704 does not appear, but waveform 705 appears, and the drop in sensor temperature T is more gradual than in waveform 703 in the case of normal ejection.

[0050] In the temperature change signal dT / dt, a waveform 706 indicates the time differential of the waveform 703 in the case of normal ejection, and a waveform 708 indicates the time differential of the waveform 705 in the case of difficult ejection.

[0051] In the waveform 706, a peak 707 appears after the timing of the characteristic point 704 of the waveform 703. As a result, in the section where the waveform 706 is equal to or greater than the discharge inspection threshold th (the section where dT / dt≧th), a pulse 702 indicating normal discharge is output as a binary signal cmp. On the other hand, in the waveform 708, since the characteristic point 704 does not appear in the waveform 705, the discharge inspection threshold th is not exceeded, and therefore the binary signal cmp is not output.

[0052] In this way, it is possible to evaluate the ink ejection state of the nozzle 1204 based on the binary signal cmp. The ejection inspection threshold value th may be registered in advance in a non-volatile memory (not shown) in the print head 3.

[0053] <Noise that may occur due to clock signals> 9A shows a part of a transfer circuit 90 that transfers a clock signal CLK, and shows, as an example, switch elements 91p and 91n that constitute an inverter circuit. The switch elements 91p and 91n are connected in series between a power supply voltage VDD and a ground voltage VSS.

[0054] 9(a), when the clock signal CLK is "0" or an L level (low level), the switch element 91p is in a conductive state and the switch element 91n is in a non-conductive state. Also, as shown in the right side of FIG9(a), when the clock signal CLK is "1" or an H level (high level), the switch element 91p is in a non-conductive state and the switch element 91n is in a conductive state.

[0055] At the timing when this clock signal CLK switches between "0" and "1", as shown in the center of Figure 9(a), switch elements 91p and 91n are substantially in a conductive state (semi-conductive state), and a through current may occur between VDD and VSS.

[0056] 9(b) shows the amount of current that may occur while the clock signal CLK is supplied at a relatively high frequency. This amount of current is mainly due to the aforementioned shoot-through current, that is, while the clock signal CLK is being supplied, a large current is generated between VDD and VSS. Therefore, a difference in the amount of current occurs at the timing of switching between supplying the clock signal CLK and suppressing the supply. This may cause noise, and may become noticeable, for example, when the transfer circuit 90 is large-scale and has a large number of elements.

[0057] Since the ground voltage VSS is also shared by the inspection circuit 201 (see FIG. 4), the above-mentioned noise may also affect the inspection by the inspection circuit 201, and may, for example, cause unexpected deformation of the signal waveform output from the temperature detection element 107 (see FIG. 8).

[0058] The clock signal CLK is used to transfer the data signals d_s and d_h, and the heat enable signal he, and therefore must be supplied at least from the start to the end of the drive of the recording element 104, which is defined by the latch signal LT. In this embodiment, when the transfer frequency is 160 MHz (6.25 μsec / bit) and the transfer data is 480 bits, a clock signal CLK of at least 3.0 μsec is required. After the transfer is completed, the supply of the clock signal CLK may be suppressed in order to reduce the aforementioned through current.

[0059] On the other hand, according to FIG. 8, in the case of normal ejection, the timing at which characteristic point 704 appears on waveform 703 is approximately 5.0 μsec after the start of driving of print element 104, which is longer than the 3.0 μsec required for supply of clock signal CLK.

[0060] 10 shows the sensor temperature T and the temperature change signal dT / dt in the same manner as in FIG. 8, and also shows the latch signal LT, the clock signal CLK, and the heat enable signal he at that time. As described above, the sensor temperature T is obtained by converting the potential difference generated in the temperature detection element 107. Therefore, as shown in the figure, noise is added to the sensor temperature T at the timing when the supply of the clock signal CLK starts (clock start timing) and the timing when the supply is suppressed (clock end timing). In this case, the clock end timing (3.0 μsec) occurs before the timing when the characteristic point 704 appears (about 5.0 μsec), so the temperature change signal dT / dt unexpectedly reaches the discharge inspection threshold value th, that is, the inspection is not performed properly due to an erroneous judgment.

[0061] <Drive control to avoid the effects of noise> 11 is a flowchart showing an example of a method for performing a discharge inspection to prevent the above-mentioned erroneous determination. This flowchart can be executed mainly by the main controller 401 and / or the print controller 419.

[0062] In step S11 (hereinafter simply referred to as "S11"; the same applies to other steps described below), the nozzle 1204 (printing element 104) to be inspected is selected as the nozzle to be inspected based on the signals LT, CLK, and D.

[0063] In S12, the discharge inspection threshold th is set. The discharge inspection threshold th can be set to a value that is a predetermined amount lower than the peak value of the sensor temperature T (potential difference of the temperature detection element 107) in the case of normal discharge. The peak value of the sensor temperature T is measured in advance and can be updated accordingly. Note that the update can be performed based on the time, the number of recordings, the time elapsed since the previous update, the replacement history of the print head 3, etc.

[0064] In S13, the setting of the clock signal CLK is changed. Details will be described later, but the changed setting may be any setting that is different from that used in the recording mode.

[0065] In S14, the discharge inspection is performed using the set discharge inspection threshold value th.

[0066] In S15, a judgment result signal Do for the nozzle being tested obtained from the test results is obtained. If the peak value of the sensor temperature T reaches the threshold value th, the judgment result signal Do becomes "1", indicating that the nozzle being tested is ejecting normally. If the peak value of the sensor temperature T does not reach the threshold value th, the judgment result signal Do becomes "0", indicating that the nozzle being tested is having difficulty ejecting.

[0067] In S16, the determination result signal Do for the nozzle to be tested is stored in the RAM 421.

[0068] In S17, it is determined whether or not the ejection inspection has been completed for all of the nozzles to be inspected. If the ejection inspection has been completed, the process proceeds to S18, and if not, the process returns to S11 and the ejection inspection is similarly performed for the other nozzles to be inspected.

[0069] In S18, the corresponding process (eg, suction operation of the nozzle 1204, wiping operation, recovery process of the print head 3, etc.) is executed based on the determination result signal Do obtained in S11 to S17.

[0070] Here, examples of the change in the setting of the clock signal CLK in S13 include changing the supply period (number of clocks) and frequency of the clock signal CLK.

[0071] -First Example 8 and 10, Fig. 12 shows the sensor temperature T and the temperature change signal dT / dt when the supply period of the clock signal CLK is changed to increase the clock count. The solid line in the figure shows the case of normal ejection, and the dashed line shows the case of ejection being difficult.

[0072] The clock signal CLK before the change is shown in the figure along with the clock signal CLK after the change for reference. The clock signal CLK before the change (clock signal CLK for recording mode) had a frequency of 160 MHz and was supplied for 3.0 μsec, which corresponds to a data transfer of 480 bits. In contrast, the clock signal CLK after the change (clock signal CLK for inspection mode) has a frequency of 160 MHz and is supplied for 9.0 μsec, which corresponds to a data transfer of 1440 bits. In other words, the number of clocks is increased by 960 bits due to the change.

[0073] As described above, in the process in which the sensor temperature T rises and then falls based on the supply of the heat enable signal he, in the case of normal ejection, the characteristic point 704 appears at a timing after about 5.0 μsec has elapsed (see FIG. 8). In this embodiment, the timing at which the supply of the clock signal CLK is stopped is after 9.0 μsec has elapsed, so that noise that may have been added to the sensor temperature T is suppressed, and therefore the temperature change signal dT / dt does not unexpectedly reach the ejection inspection threshold value th (see FIG. 12).

[0074] That is, according to this embodiment, the number of clocks is added until the temperature change signal dT / dt becomes sufficiently smaller than the threshold value th (here, the timing after 9.0 μsec has elapsed). As a result, noise that may occur due to the suppression of the supply of the clock signal CLK does not substantially affect the discharge inspection. Therefore, according to this embodiment, the erroneous judgment described with reference to FIG. 10 is prevented, and the discharge inspection can be properly performed.

[0075] -Second Example 8, 10 and 12, Fig. 13 shows the sensor temperature T and the temperature change signal dT / dt when the number of clocks is increased and the frequency of the clock signal CLK is decreased. The clock signal CLK after the change (for inspection mode) is supplied at a frequency of 53 MHz (about 1 / 3 of the frequency of the first embodiment) for about 9.0 μsec corresponding to the transfer of 480 bits of data. That is, in this embodiment, the supply time of the clock signal CLK is about three times longer than before the change (for recording mode), while the frequency is about 1 / 3, resulting in a smaller amount of data transferred per unit time.

[0076] In this embodiment, the supply of the clock signal CLK is stopped after 9.0 μsec has elapsed, suppressing noise that may have been added to the sensor temperature T, and therefore the temperature change signal dT / dt does not unexpectedly reach the discharge inspection threshold value th. Furthermore, lowering the frequency of the clock signal CLK makes it possible to further reduce noise that may have been added to the sensor temperature T, which can be advantageous in further preventing erroneous determinations.

[0077] -Variations Since it is sufficient for the clock signal CLK to avoid noise that may affect the discharge inspection, it is preferable that the clock signal CLK is supplied at least until after the timing at which a characteristic point 704 corresponding to a peak in the waveform of the time derivative of the signal waveform 703 obtained from the temperature detection element 107 appears. Therefore, the frequency of the clock signal CLK may be increased to increase the amount of data transferred per unit time, without departing from the spirit of the invention.

[0078] In addition, in the second embodiment described above, since the noise that may be added to the sensor temperature T can be reduced, it is also possible to shorten the supply time of the clock signal CLK, in which case the through current described with reference to FIG. 9(a) becomes smaller, and the noise can be further reduced. Therefore, in the inspection mode, the supply time and / or frequency of the clock signal CLK may be changed from those in the recording mode and adjusted within the scope of the invention. The adjustment is typically performed by the print controller 419 of the print engine unit 417, but may also be performed by the controller unit 410.

[0079] To summarize the above, the recording device 1000 includes, as operation modes, a recording mode in which recording is performed without performing a discharge inspection, and an inspection mode in which a discharge inspection is performed based on a recording performed for the discharge inspection. In the inspection mode, the clock signal used for data transfer is generated in a manner different from that in the recording mode, and the supply time and / or frequency is changed. According to this control manner, noise that may occur due to suppression of the supply of the clock signal CLK does not substantially affect the discharge inspection, so that appropriate discharge inspection can be realized.

[0080] <Program> The present invention may 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 a computer of the system or device read and execute the program. For example, the present invention may be realized by a circuit (e.g., ASIC) that realizes one or more functions.

[0081] <Other> In the above description, the recording device 1000 using the inkjet recording method is taken as an example, but the recording method is not limited to the above. The recording device 1000 may be a single-function printer having only a recording function, or a multifunction printer having multiple functions such as a recording function, a FAX function, and a scanner function. It may also be a manufacturing device for manufacturing color filters, electronic devices, optical devices, microstructures, etc. using a predetermined recording method.

[0082] In addition, the term "recording" in this specification should be interpreted broadly. Therefore, the form of "recording" does not matter whether the object formed on the recording medium is significant information such as characters or figures, and also does not matter whether it is visible to humans or not.

[0083] In addition, the term "recording medium" should be interpreted broadly, just like the above-mentioned "recording." Therefore, the concept of a "recording medium" includes not only commonly used paper, but also any material capable of receiving ink, such as cloth, plastic film, metal plate, glass, ceramics, resin, wood, leather, etc.

[0084] Furthermore, "ink" should be interpreted broadly, just like the above-mentioned "recording". Therefore, the concept of "ink" includes not only liquid that is applied onto a recording medium to form an image, design, pattern, etc., but also accompanying liquid that can be used for processing the recording medium, processing the ink (for example, solidifying or insolubilizing the coloring material in the ink applied to the recording medium), etc. From this perspective, the recording head may be expressed as a liquid ejection head, etc., and the recording device may be expressed as a liquid ejection device, etc.

[0085] In addition, in the embodiments, each element is named based on its main function, but the functions described in the embodiments may be sub-functions and are not strictly limited to those expressions. Furthermore, those expressions can be replaced with similar expressions. In the same spirit, the expression "unit" can be replaced with "tool," "component," "member," "structure," "assembly," etc. Alternatively, those expressions may be omitted or added.

[0086] In addition, two or more elements exemplified as selectable in the embodiments are not strictly limited to the examples, and may be arbitrarily combined, for example, each of the two or more exemplified elements may be additionally or alternatively selected. As an example, when two elements A and B can be arbitrarily combined, it may be expressed as "A and / or B" or "at least one of A and B" to indicate that it is either A only, B only, or both A and B.

[0087] <Summary of the embodiment> Some features exemplified in the embodiments are summarized as follows: [1] A recording device having a plurality of nozzles for performing recording by ejecting ink, a plurality of heating elements provided corresponding to the plurality of nozzles, each heating element heating ink to cause the ink to be ejected from a corresponding nozzle; A plurality of temperature detection elements provided corresponding to the plurality of heating elements; an inspection means for inspecting the state of ink ejection from the nozzles based on signals from the plurality of temperature detection elements; A signal generating means for generating a clock signal, as operation modes, a recording mode in which recording is performed by the plurality of heating elements without performing an inspection by the inspection means, and an inspection mode in which inspection is performed by the inspection means based on the recording performed by the plurality of heating elements, In the inspection mode, the signal generating means generates a clock signal in a manner different from that in the recording mode. A recording apparatus comprising: [2] The time when the clock signal is supplied in the inspection mode is different from the time when the clock signal is supplied in the recording mode. The recording device according to [1], [3] The time during which the clock signal is supplied in the inspection mode is longer than the time during which the clock signal is supplied in the recording mode. The recording device according to [2], [4] In the inspection mode, the signal generating means supplies a clock signal at least until a point in time after a characteristic point corresponding to a peak in a waveform of a time derivative of the signal waveform obtained from the temperature detection element appears. The recording device according to [3], [5] The frequency of the clock signal supplied in the inspection mode is different from the frequency of the clock signal supplied in the recording mode. The recording device according to [1], [6] The frequency of the clock signal supplied in the inspection mode is lower than the frequency of the clock signal supplied in the recording mode. The recording device according to [5], [7] In the inspection mode, the signal generating means further includes a selecting means for selecting one of the plurality of heating elements to be driven and one of the plurality of temperature detecting elements corresponding to the one to be driven. The recording device according to [1], [8] The signal generating means further generates a signal indicating a drive time of the driven object. The recording device according to [7], [9] The recording medium may further include a correction unit that corrects recording data for driving the heating elements based on the inspection result received from the inspection unit. The recording device according to [8],

[10] A program for causing a computer to function as each element of the recording device according to any one of [1] to [9]. The program may be stored in a computer-readable storage medium so as to be executable by one or more processor circuits with a memory.

[0088] The invention is not limited to the above-described embodiments, and various modifications and variations are possible without departing from the spirit and scope of the invention. Accordingly, the following claims are appended to apprise the public of the scope of the invention. [Explanation of symbols]

[0089] 1000: printing device, 3: print head, 1204: nozzle, 102: data input circuit, 103: printing element selection circuit, 106: temperature detection element selection circuit, 104: printing element, 107: temperature detection element, 201: inspection circuit.

Claims

1. A recording device having a plurality of nozzles for performing recording by ejecting ink, a plurality of heating elements provided corresponding to the plurality of nozzles, each heating element heating ink to cause the ink to be ejected from a corresponding nozzle; A plurality of temperature detection elements provided corresponding to the plurality of heating elements; an inspection means for inspecting the state of ink ejection from the nozzles based on signals from the plurality of temperature detection elements; A signal generating means for generating a clock signal, as operation modes, a recording mode in which recording is performed by the plurality of heating elements without performing an inspection by the inspection means, and an inspection mode in which inspection is performed by the inspection means based on the recording performed by the plurality of heating elements, In the inspection mode, the signal generating means generates a clock signal in a manner different from that in the recording mode. A recording apparatus comprising:

2. The time when the clock signal is supplied in the inspection mode is different from the time when the clock signal is supplied in the recording mode.

2. The recording apparatus according to claim 1.

3. The time during which the clock signal is supplied in the inspection mode is longer than the time during which the clock signal is supplied in the recording mode.

3. The recording apparatus according to claim 2.

4. In the inspection mode, the signal generating means supplies a clock signal at least until a point in time after a characteristic point corresponding to a peak in a waveform of a time derivative of the signal waveform obtained from the temperature detection element appears.

4. The recording apparatus according to claim 3.

5. The frequency of the clock signal supplied in the inspection mode is different from the frequency of the clock signal supplied in the recording mode.

2. The recording apparatus according to claim 1.

6. The frequency of the clock signal supplied in the inspection mode is lower than the frequency of the clock signal supplied in the recording mode.

6. The recording apparatus according to claim 5.

7. In the inspection mode, the signal generating means further includes a selecting means for selecting one of the plurality of heating elements to be driven and one of the plurality of temperature detecting elements corresponding to the one to be driven.

2. The recording apparatus according to claim 1.

8. The signal generating means further generates a signal indicating a drive time of the driven object.

8. The recording apparatus according to claim 7.

9. The recording medium may further include a correction unit that corrects recording data for driving the heating elements based on the inspection result received from the inspection unit.

9. The recording apparatus according to claim 8.

10. A program for causing a computer to function as each element of the recording device according to any one of claims 1 to 9.

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