Liquid discharge device, control method, storage medium, and program
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- CANON KK
- Filing Date
- 2023-06-16
- Publication Date
- 2026-06-05
Smart Images
Figure 00000000_0000_ABST
Abstract
Description
[Technical field]
[0001] The present invention relates to a liquid ejection device. [Background technology]
[0002] An inkjet recording device is known as an example of a liquid ejection device. In recent years, there has been a demand for inkjet recording devices to be adaptable to higher image quality, higher speeds, and a greater variety of inks. In addition, ink droplets ejected from each nozzle are becoming smaller. In order to maintain a constant quality of the recorded image, it is important to understand the fluctuations in the nozzle ejection performance. Patent Document 1 discloses a technology for optically detecting the ejection state of ejected ink droplets and determining the fluctuations in the nozzle ejection performance. [Prior art documents] [Patent documents]
[0003] [Patent Document 1] JP 2007-152853 A Summary of the Invention [Problem to be solved by the invention]
[0004] The detection results of the droplet ejection state are affected by individual differences in devices, nozzles, sensors, etc. If a uniform threshold value for judgment is set and applied to all devices, the influence of such individual differences may make it impossible to properly judge fluctuations in the nozzle ejection performance.
[0005] The present invention provides a technique for more appropriately determining fluctuations in the ejection performance of a nozzle. [Means for solving the problem]
[0006] According to the present invention, A detection means for detecting liquid discharged from the nozzle of the discharge head; A determination means for determining whether or not the ejection performance of the nozzle has deteriorated; A liquid ejection device comprising: the nozzle is provided with an energy generating element that generates energy for ejecting liquid, The determination means is determining whether or not the ejection performance of the nozzle has deteriorated by comparing a detection result of the detection means when the energy generating element is driven under a first driving condition with a reference value; The reference value is The energy generating element is driven under a second driving condition in which the energy is lower than that of the first driving condition, and the second driving condition is set based on a detection result of the detection means. A liquid ejection device is provided. Effect of the Invention
[0007] According to the present invention, it is possible to provide a technique for more appropriately determining fluctuations in the ejection performance of a nozzle. [Brief description of the drawings]
[0008] [Figure 1] 1 is an external view of a liquid ejection device according to an embodiment of the present invention. [Diagram 2] FIG. 2 is an explanatory diagram showing the internal mechanism of the liquid ejection device of FIG. [Diagram 3] (A) is an explanatory diagram of the ejection surface, and (B) is an explanatory diagram of the detection unit. [Figure 4] FIG. 2 is a block diagram of a control unit of the recording apparatus of FIG. 1. [Diagram 5] 13A and 13B are diagrams showing examples of detection signals from a detection unit. [Figure 6] 5A to 5C are diagrams showing examples of detection modes of a liquid by a detection unit. [Figure 7] 13A and 13B are diagrams showing examples of how a liquid passes through a detection position. [Figure 8] 13A and 13B are diagrams showing examples of detection results of the detection unit. [Figure 9] 6A and 6B are diagrams showing examples of ejection state values calculated from detection results. [Figure 10]13A to 13C are diagrams showing examples of a method for setting a reference value. [Figure 11] 5 is a flowchart showing an example of processing by the control unit in FIG. 4; [Figure 12] 5 is a flowchart showing an example of processing by the control unit in FIG. 4; 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] <Outline of the liquid ejection device> 1 is an external view of a liquid ejection device 1 according to one embodiment of the present invention. In each drawing, arrows X, Y, and Z indicate directions that intersect with each other, and in this embodiment, arrows X and Y are horizontal directions that are perpendicular to each other and indicate the width direction and depth direction of the liquid ejection device 1, and arrow Z indicates the up-down direction (height direction).
[0011] The liquid ejection device 1 of this embodiment is an inkjet recording device that ejects ink as a liquid onto a recording medium to record an image on the recording medium. In this embodiment, a case where the present invention is applied to a serial type inkjet recording device will be described, but the present invention can also be applied to other types of recording devices.
[0012] Furthermore, "recording" includes not only the formation of meaningful information such as characters and figures, but also the formation of images, patterns, and the like on a recording medium, whether meaningful or unmeaning, or the processing of the medium, regardless of whether it is manifested in a way that can be visually perceived by humans. In addition, in this embodiment, a sheet of paper is assumed as the "recording medium", but it may also be cloth, plastic, film, and the like. The liquid ejection device 1 is capable of recording on a number of different types of recording media with different widths, and can record on recording media up to a maximum size of 60 inches, for example. Roll paper or cut paper can be used as the recording medium.
[0013] The liquid ejection device 1 includes a device main body 10, a guide 11 on which recorded recording media are loaded, a display panel 13 for displaying various recording information and setting results, and operation buttons 12 for setting the recording mode, type of recording media, etc. The liquid ejection device 1 also includes a tank unit 14 that houses a plurality of ink tanks that store inks of colors such as black, cyan, magenta, and yellow.
[0014] 2 is a perspective view showing the internal configuration of the device body 10 of the liquid ejection device 1. The device body 10 is provided with a transport unit 5 that transports the recording medium 200 in the Y direction on a platen 6. The transport unit 5 includes a transport roller and a nip roller that is in pressure contact with the transport roller. The recording medium 200 is held between these rollers and transported by the rotation of the transport roller.
[0015] The device body 10 is provided with a carriage 2 and a moving mechanism 4 that moves the carriage 2 back and forth in the X direction. In this embodiment, the moving mechanism 4 is a belt transmission mechanism. Specifically, the moving mechanism 4 includes pulleys 42 and 43 spaced apart in the X direction, an endless belt 44 wound around the pulleys 42 and 43, a carriage motor 41 that rotates the pulley 42, and a rail 48 that extends in the X direction and guides the movement of the carriage 3. The carriage 3 has a fixed portion 45 fixed to the endless belt 44. The endless belt 44 runs when driven by the carriage motor 41, and the carriage 3 can move along the rail 48.
[0016] A linear scale 47 arranged in the X direction is also provided on the device body 10. The position of the carriage 3 in the X direction is detected by reading the linear scale 47 with an encoder sensor 46 provided on the carriage 3.
[0017] A plurality of ejection heads 3 are mounted on the carriage 3. Each ejection head 3 ejects liquid. In this embodiment, each ejection head 3 is a recording head that ejects ink supplied from a tank unit 14 onto a recording medium 200 to record an image. In this embodiment, each ejection head 3 is detachably mounted on the carriage 3 and can be replaced. In this embodiment, three ejection heads 3 are mounted on the carriage 3, but the number of ejection heads 3 may be one. Each ejection head 3 is disposed to face the platen 6, and an ejection surface 30 is formed on the lower surface of the ejection head 3. Ink is ejected from the ejection surface 30 onto the recording medium 200 supported by the platen 6.
[0018] 3(A) is a bottom view of the ejection head 3, showing the ejection surface 30. The ejection surface 30 is provided with a plurality of nozzles 31 that eject ink. Each nozzle 31 includes an ejection port 32 that opens in the ejection surface 30, and an energy generating element 33 provided in the ejection port 32. The energy generating element 33 is an electro-thermal conversion element (heater), and generates energy for ejecting ink from the ejection port 32 when power is supplied. The energy generating element 33 may be a piezoelectric element.
[0019] A common liquid chamber 34 for each type of ink is provided in the ejection head 3. Ink is supplied to the ejection ports 32 from the common liquid chamber 34 via a flow path 35, and the ink is ejected from the ejection ports 32 by driving the energy generating elements 33.
[0020] For example, 2048 nozzles 31 are provided. The ejection openings 32 are arranged in a staggered pattern, not in a single row. When numbers are assigned in order from one end of the nozzle row to distinguish between the nozzles, the nozzle row is divided into two rows, an odd-numbered nozzle row 30a and an even-numbered nozzle row 30b. These nozzle rows may be called an odd-numbered nozzle row (Odd row) and an even-numbered nozzle row (Even row). The odd-numbered nozzle row and the even-numbered nozzle row each include, for example, 1024 nozzles, and the interval between the two is about 0.6 mm. In addition, a recording resolution of 1200 dpi (dots per inch) is realized by combining both the odd-numbered nozzle row and the even-numbered nozzle row in each nozzle row. The nozzle interval in each nozzle row is 600 dpi. In addition, the amount of ink droplets ejected from the ejection openings 32 is, for example, about 4 pl to 6 pl.
[0021] Please refer to FIG. 2. The carriage 3 is provided with a distance detection unit 21 for detecting the distance between the recording medium 200 on the platen 6 and the ejection surface 30. The distance detection unit 21 is, for example, an optical sensor. The rail 48 is provided with a lift cam (not shown) for varying its height in stages, and a lift motor 49 for driving the lift cam. By changing the height of the rail 48 based on the detection result of the distance detection unit 21, it is possible to raise and lower the carriage 3, that is, raise and lower the ejection head 3. This makes it possible to adjust the distance between the ejection head 3 and the recording medium 200.
[0022] A droplet detection unit 7 and a recovery unit 8 are provided within the movement range of the carriage 3. The recovery unit 8 is a unit that maintains and recovers the discharge performance of the discharge head 3. The recovery unit 8 includes, for example, a cap that covers the discharge surface 30, and a suction device (pump) that sucks ink from the discharge surface 30 through the cap. By sucking ink from the discharge surface 30 through the cap, foreign matter in and around the discharge ports 32 is removed, and the discharge performance of the discharge head 3 can be recovered.
[0023] The droplet detection unit 7 is disposed at a position within the movement range of the carriage 3, between the recording area of an image on the recording medium 200 and the recovery unit 8. The droplet detection unit 7 of this embodiment is an optical sensor that optically detects flying droplets. Fig. 3(B) is a cross-sectional view showing the structure of the droplet detection unit 7.
[0024] The droplet detection unit 7 is an optical sensor including a light emitting element 71 and a light receiving element 72 spaced apart in the Y direction. The droplet detection unit 7 includes a housing 70 that forms a groove 70a that opens upward, and the light emitting element 71 and the light receiving element 72 are supported by the housing 70 so as to sandwich the groove 70a.
[0025] The light-emitting element 71 emits a light beam 74, and the light-receiving element 72 receives the light beam 74 emitted by the light-emitting element 71. The sensor circuit 73 detects the amount of light received by the light-receiving element 72. The light beam 74 defines the detection position of the droplet, and when a droplet passes through the light beam 74, the amount of light received by the light-receiving element 72 changes. This allows the droplet to be detected.
[0026] The sensor circuit 73 includes a current-voltage conversion circuit that converts the current flowing according to the amount of light received by the light receiving element 72 into a voltage signal and outputs it, and an amplifier circuit for amplifying the level of the ink droplet detection signal. It also includes a clamp circuit for removing the effects of output saturation and a decrease in S / N ratio caused by fluctuations in the level of the ink droplet ejection detection signal due to disturbances. The clamp circuit holds the level of the signal output from the amplifier circuit at a specified value (clamp voltage) until just before ejection is observed.
[0027] These circuits detect minute changes in the amount of received light, such as the passage of ink droplets, and therefore ensure the level of the detection signal. When an ink droplet passes through the light beam 74 of the droplet detection unit 7, the amount of light received by the light receiving element 72 changes, and an internal comparator compares the level of the detection signal output as the detection result with a predetermined value. Based on the comparison result, the ejection state of the nozzle 31 being detected, and in particular the flight state of the ejected ink droplets, can be determined.
[0028] The droplet detection unit 7 is disposed so that the optical axis of the light beam 74 is at the same position in the Z direction as the support surface of the platen 6 (support surface of the recording medium 200). The discharge state can be inspected under the same conditions as when an image is recorded on the recording medium 200. Slits are provided near the light emitting element 71 and the light receiving element 72. The light beam 74 incident on the light receiving element 72 can be narrowed to improve the S / N ratio. The cross-sectional area of the light beam 74 is, for example, about 2 mm x 2 mm. The parallel light projection area of the ink droplet when the ink droplet passes through the light beam 74 is, for example, about 2^-3 (mm^2). In this embodiment, the nozzle rows 30a, 30b and the light beam 74 are disposed in a parallel relationship with each other, and the creepage distance in the height direction (Z direction) between the nozzle rows 30a, 30b and the light beam 74 is, for example, 2 to 10 mm.
[0029] <Control system configuration> 4 is a block diagram of the control unit 9 of the liquid ejection device 1. The control unit 9 is a control circuit that controls the entire liquid ejection device 1. The control unit 9 includes a CPU 91, which is a processor that controls the entire device, a storage device 92 such as a semiconductor memory, and a sensor / motor control circuit 93 that controls each sensor and each motor. The CPU 91, the sensor / motor control circuit 93, and the storage device 92 are connected to each other so that they can communicate with each other.
[0030] The storage device 92 stores the programs executed by the CPU 91 and various information. The various information includes, for example, detection data and reference values related to the discharge state, and information on the thickness of the recording medium 200. The sensor motor control circuit 93 controls the distance detection unit 21, the droplet detection unit 7, the sheet detection unit 96, the carriage motor 41, the transport motor 95, and the lift motor 49, and processes the detection results. The transport motor 95 is the drive source of the transport unit 5, and rotates the transport roller. The sheet detection unit 96 is a sensor that detects the position of the recording medium 200. In addition, the sensor motor control circuit 93 controls the discharge of ink from the discharge head 3 via the head control circuit 94 based on the position information of the carriage 2 detected by the encoder sensor 46.
[0031] Image data sent from the host device 100 is converted into an ejection signal by the CPU 91, and ink is ejected from the ejection head 3 in accordance with the ejection signal to perform an image recording operation on the recording medium 200. The recording operation is performed by alternately repeating an intermittent transport operation of the recording medium 200 and a recording scan operation. The intermittent transport operation is an operation in which the recording medium 200 is transported a predetermined amount and then stopped, and is performed by the transport unit 5. The recording scan operation is an operation in which, while the transport of the recording medium 200 is stopped, the carriage 2 is moved to move the ejection head 3 in the width direction of the recording medium 200, while ejecting ink. The recording operation of the image on the recording medium 200 progresses.
[0032] The CPU 91 includes, as its functional blocks, for example, a driver section, a sequence control section, an image processing section, a timing control section, and a head control section. The sequence control section controls the overall recording control, specifically, starts and stops the image processing section, the timing control section, and the head control section, controls the transportation of the recording medium, and controls the movement of the carriage 2. The control of each functional block is executed by the sequence control section reading various programs from the storage device 92 and executing them. The driver section generates control signals to the sensor motor control circuit 93, the storage device 92, the head control circuit 95, etc. based on commands from the sequence control section, and also transmits input signals from each block to the sequence control section.
[0033] The image processing unit performs image processing to separate and convert the input image data from the host device 100 into color separation and conversion, and convert it into print data that can be printed by the ejection head 3. The timing control unit transfers the print data converted and generated by the image processing unit to the head control unit in conjunction with the position of the carriage 2. The timing control unit also controls signals synchronized with the ejection from each nozzle to determine the ejection state of droplets. The head control unit converts the print data input from the timing control unit into an ejection signal and outputs it. Also, if correction is required based on a command from the sequence control unit, it outputs an adjustment control signal for correction and transmits it to the head control circuit 94. The head control circuit 94 generates a drive pulse according to the ejection signal input from the head control unit and applies it to the ejection head 3.
[0034] <Liquid discharge and detection> An example of inspecting the ejection state of the nozzle 31 will be described with reference to Figures 5(A) and 5(B). Figure 5(A) shows a case where ink is ejected normally from the ejection head 3, and Figure 5(B) shows a case where ink is not ejected normally (non-ejection state) from the ejection head 3. In both figures, it is assumed that the nozzle to be inspected is nozzle number N.
[0035] Each of these figures also shows a timing chart of the ejection signal, which is a drive pulse that drives the ejection head 3 (energy generating element 33), and the detection signal, which is the result of detection of ink droplets by the droplet detection unit 7. The clamp circuit described above is operated in synchronization with the ejection of ink droplets, and the signal level of the detection signal that is output is held at a predetermined clamp voltage value immediately before the ejection of an ink droplet is observed.
[0036] When the ejection of ink droplets starts, the operation of the clamp circuit is released just before the ink droplets ejected toward the light beam 74 pass through the light beam 74. When the detection signal indicating the amount of light received by the light receiving element 72 falls below the reference voltage, it is determined that the ejection is normal. The reference voltage value is set by confirming in advance by an experiment or the like the amount of light received by the light receiving element 72 when the ink droplets pass through the light beam 74.
[0037] In the example of Fig. 5(A), the nozzle to be inspected, No. N, is judged to be in a normal ejection state. Note that in the illustrated example, in order to improve the reliability of the inspection, ejection from No. N is performed multiple times, and the judgment is made based on these results.
[0038] When no ink droplets are ejected from nozzle No. N, the ink droplets do not block the light beam 74, and there is no decrease in the amount of light received by the light receiving element 72. In the example of Fig. 5(B), no voltage drop in the detection signal is confirmed. Therefore, the nozzle No. N that is the subject of inspection here is not ejecting normally, and is determined to be in a non-ejection state.
[0039] Next, as described above, in this embodiment, ink is ejected while the ejection head 3 is moved in the width direction of the recording medium 200 by the movement of the carriage 2 during the recording scan operation. Figure 6 shows a schematic diagram of the relationship between the ink droplets ejected in this state and the droplet detection unit 7.
[0040] The ink droplets ejected from the ejection head 3 may be ejected separately into a main droplet and a small droplet other than the main droplet (hereafter referred to as a satellite), or may be ejected in a state where the main droplet and the satellite are not separated and are stuck together. This is due to differences in nozzle diameter, differences in the type (characteristics) of ink, differences between the odd-numbered nozzle row 30a and the even-numbered nozzle row 30b, etc.
[0041] When the main droplet and the satellite are ejected separately, the main droplet and the satellite are ejected from the same position at the moment of ejection, but the landing position on the recording medium 200 may differ due to the difference in the ejection speed of the two. Therefore, in order to detect the change in the landing position and the dot shape, it is desirable to detect the ejection state under the same control conditions as when recording the image when inspecting the nozzle 31. Therefore, in this embodiment, when detecting the ejection state of the nozzle 31 using the droplet detection unit 7, the carriage 2 and the ejection head 3 are driven under the same conditions as when recording the image. However, when detecting the ejection state of the nozzle 31, it is not essential to drive the carriage 2 and the ejection head 3 under the same conditions as when recording the image.
[0042] 7(A) and 7(B) show examples in which ink droplets ejected from the ejection head 3 are detected by the droplet detection unit 7 while the carriage 2 is moving. Fig. 7(A) shows an example in which an ink droplet is separated into a main droplet MD and a satellite SD, and Fig. 7(B) shows an example in which the main droplet MD and the satellite SD are joined together.
[0043] Fig. 8(A) is a timing chart of the ejection signal SG, the comparison judgment result CR, the detection signal DD, and the reference voltage REFV in the example of Fig. 7(A). Fig. 8(B) is a timing chart of the ejection signal SG, the comparison judgment result CR, the detection signal DD, and the reference voltage REFV in the example of Fig. 7(B). The comparison judgment result CR is an output signal of a comparator provided in the sensor circuit 73. The comparison judgment result CR is maintained at a low level (L level) when the detection signal DD is equal to or higher than the reference voltage REFV, and changes to a high level (H level) when the detection signal DD falls below the reference voltage REFV.
[0044] When the main droplet MD and satellite SD are separated as in Fig. 7(A), the ejection size and ejection speed of each droplet are different. Therefore, as shown in Fig. 8(A), the detection signal DD has two peaks corresponding to the main droplet MD and satellite SD, respectively, and the comparison judgment result CR changes to H level twice.
[0045] When the main droplet MD and the satellite SD are integrated as shown in FIG. 7B, only one peak appears in the detection signal DD as shown in FIG. 8B, and the comparison judgment result CR also changes to H level once.
[0046] Figures 9(A) and 9(B) show examples of ejection state values calculated from the detection signal DD and the comparison judgment result CR. Figure 9(A) shows an example where an ink droplet is separated into a main droplet MD and a satellite SD, and Figure 9(B) shows an example where the main droplet MD and the satellite SD are joined together. The ejection state value includes an amplitude ΔX, a change time ΔY, and a peak detection time ΔZ.
[0047] The amplitude ΔX is the maximum amplitude of the detection signal DD. The change time ΔY is the time during which the comparison judgment result CR is at H level. When the main droplet MD and the satellite SD are separated, as shown in FIG. 9(A), the comparison judgment result CR becomes H level twice, so the change time ΔY is the time from the first rising edge of H level to the second falling edge of H level. The peak detection time ΔZ is the time from the start of ejection to when the degree of blocking of the light beam 74 by the ink droplet reaches its maximum, and in this embodiment, it is the time from the falling edge of the ejection signal SG to the peak value of the detection signal DD.
[0048] The ejection volume of one ink droplet can be calculated from the amplitude ΔX and the change time ΔY. If the ejection volume is large, the ink droplet size will be large, and the amplitude ΔX and the change time ΔY will be large. The ejection speed of the ink droplet can be calculated from the peak detection time ΔZ. Since the distance between the ejection surface 30 and the detection position (light beam 74) of the droplet detection sensor 7 is known by design, the peak detection time ΔZ will be shorter if the ejection speed is fast.
[0049] The CPU 91 is provided with the data of the detection signal DD and the comparison judgment result CR, and the CPU 91 stores the provided data in the storage device 92. The CPU 91 then reads out the detection results of the droplet detection unit 7 from the storage device 92 and calculates the discharge speed and discharge amount of the nozzle 31 to be inspected.
[0050] <Changes in discharge performance and their inspection> Changes in the ejection performance of the nozzle 31 affect the recording quality. For example, if the ejection speed changes, the landing position on the recording medium 200 shifts. In that case, for example, when recording a single vertical line, the line may become thicker and eventually the single line may become two lines, degrading the recording quality. Similarly, if the ejection amount changes and the droplet size changes, the density of the image recorded on the recording medium 200 is affected. For example, when recording an image by overlapping magenta and cyan, the density balance changes and the recording quality decreases.
[0051] Therefore, it is necessary to inspect the change in the ejection performance of the nozzle 31, and if there is a change in the ejection performance, it is necessary to take measures such as correcting the change or replacing the ejection head 3. In general, the ejection performance of the nozzle 31 decreases over time or with the degree of use. FIG. 10(A) shows a theoretical example in which the decrease in the ejection performance is expressed by shortening the pulse width (power supply time) of the ejection signal SG. The dashed line shows the detection signal DD when the pulse width of the ejection signal SG is the normal pulse width (the pulse width during image recording), and the solid line shows the detection signal DD when the pulse width of the ejection signal SG is shorter than the normal pulse width.
[0052] By shortening the pulse width of the ejection signal SG, the ON time of the energy generating element 33 is shortened, that is, the generated energy is reduced. This is equivalent to a decrease in ejection performance. By shortening the pulse width of the ejection signal SG, the energy generated by the energy generating element 33 is reduced, so the ejection speed is slowed and the ejection amount is reduced. In this way, the amplitude Δα, the change time Δβ, and the peak detection time Δγ obtained by intentionally or virtually reducing the ejection performance of the nozzle 31 can be a reference value (determination value) for determining the deterioration of the ejection performance of the nozzle 31. In other words, the amplitude ΔX, the change time ΔY, and the peak detection time ΔZ actually measured with the pulse width of the ejection signal SG as the normal pulse width are compared with the amplitude Δα, the change time Δβ, and the peak detection time Δγ, and if the difference is small, it can be determined that the performance of the nozzle 31 is degraded.
[0053] However, if the reference value is theoretically calculated and set, it may not be possible to respond to changes in the discharge performance of the nozzle 31 due to individual differences. That is, there is variation in the sensitivity of the droplet detection unit 7. Also, there is a tolerance in the diameter of the discharge port 31. Such errors are examples of factors that prevent the use of a common reference value between devices.
[0054] For example, even when the liquid ejection device 1 is used under the exact same conditions, there may be cases where the performance degradation is large (when the change in the detection signal DD is large) as in the example of Fig. 10(B) or cases where the performance degradation is small (when the change in the detection signal DD is small) as in the example of Fig. 10(C). Therefore, there are cases where the theoretically determined unified reference value cannot accurately determine the degradation in the ejection performance of the nozzle 31.
[0055] Therefore, in this embodiment, before any degradation in performance of the nozzle 31 occurs, the amplitude Δα, change time Δβ, and peak detection time Δγ are actually measured in advance and used as reference values. Specifically, the drive conditions (e.g., pulse width) of the energy generating element 33 are set so that the energy generated by the energy generating element 33 is smaller than that during image recording, and ink is ejected from the nozzle 31 while the recording head 3 is moved by moving the carriage 2. The ink droplets are actually detected by the droplet detection unit 7, and the amplitude Δα, change time Δβ, and peak detection time Δγ are calculated. These measured values are stored in the storage device 92 as reference values.
[0056] When ink is ejected from the nozzles 31 while the recording head 3 is moving, as described with reference to Figs. 6 to 9, there are cases where the ink droplets are separated into a main droplet MD and a satellite SD, and cases where the ink droplets are integrated. These cases can be distinguished on a nozzle 31 basis, for example, between the odd-numbered nozzle row 30a and the even-numbered nozzle row 30b. In such a case, a reference value (for separation) when the ink droplets are separated into a main droplet MD and a satellite SD, and a reference value (for integration) when the ink droplets are integrated without being separated may be prepared and stored in the storage device 92. Then, during the inspection, one of the reference value (for separation) and the reference value (for integration) may be selectively used according to the nozzle 31 to be inspected. Alternatively, only the reference value (for separation) may be prepared and stored in the storage device 92, and the reference value (for integration) may be calculated by correcting the reference value (for separation).
[0057] In addition, when obtaining the reference value, an example of setting the drive condition of the energy generating element 33 so that the energy generated by the energy generating element 33 is smaller than that during image recording may be other than the pulse width of the ejection signal SG. Any drive condition may be used as long as it can reduce the energy.
[0058] The reference value may be a value calculated using the ratio of change from a theoretical value, instead of using the amplitude Δα, the change time Δβ, and the peak detection time Δγ as they are. Also, the reference value may be calculated using the results of a plurality of ejection conditions, instead of using a single ejection condition.
[0059] <Processing example> A description will now be given of an example of processing executed by the CPU 91 of the control unit 9 in relation to the determination of performance degradation of the nozzle 31. Fig. 11 is a flow chart showing an example of processing relating to setting of a reference value.
[0060] In step S1, it is determined whether or not a start condition is satisfied. Examples of the start condition include initial operation (initial power-on) when the liquid ejection device 1 is operated for the first time, replacement of the ejection head 3, adjustment of the registration of a recorded image, and adjustment of the density of a recorded image. In this way, when the ejection head 3 or recording control is initialized, a reference value can be set.
[0061] If it is determined that the start condition is met, the process proceeds to step S2. In step S2, the target nozzles 31 for which a reference value is to be set are selected. The reference value may be set individually for all nozzles 31, or may be set separately for the odd-numbered nozzle row 30a and the even-numbered nozzle row 30b. In the latter case, the target nozzles 31 may be selected one by one from the odd-numbered nozzle row 30a and the even-numbered nozzle row 30b.
[0062] In step S3, the ejection conditions are set. This setting includes setting the drive conditions of the energy generating element 33 corresponding to the nozzle 31 selected in step S2. The drive conditions of the energy generating element 33 (e.g., the pulse width of the ejection signal) are set so that the generated energy is smaller than that during image recording. Other conditions, such as the height and movement speed of the carriage 2 and the ink ejection timing (ejection position at which ink droplets are detected by the droplet detection unit 7), are the same as those during image recording. Note that in the movement of the carriage 2, there are an acceleration region and a constant speed region (constant speed region), but since the majority of ink ejection for image recording is performed in the constant speed region, ink is also ejected to the droplet detection unit 7 in the constant speed region.
[0063] In step S4, ink is ejected under the ejection conditions set in step S3. Here, similar to when recording an image, the carriage 3 is moved so that the ejection head 3 passes over the droplet detection unit 7, and ink is ejected from the ejection head 3 during the movement. In step S5, a process is performed in which the droplet detection unit 7 detects the ink droplets ejected from the ejection head 3. The detection result of the droplet detection unit 7 is stored in the storage device 92 in association with the selected nozzle 31.
[0064] In step S6, it is determined whether data acquisition has been completed for all nozzles 31 for which reference values are to be set, and if not, the process returns to step S2 to select another nozzle 31 and perform the same process.
[0065] In step S7, a reference value is calculated from the data stored in the storage device 92 in step S5. The reference value is, for example, the amplitude Δα, the change time Δβ, and the peak detection time Δγ described above, and is calculated for each target nozzle 31. In step S8, the reference value calculated in step S7 is stored in the storage device 92 in association with the target nozzle 31.
[0066] FIG. 12 is a flow chart showing an example of a process for inspecting the nozzle 31 and determining whether the ejection performance of the nozzle 31 has deteriorated. In step S11, it is determined whether the start condition is satisfied. The ejection performance of the nozzle 31 may change when ink droplets are ejected. On the other hand, the ejection performance hardly changes after ejecting a few droplets. Therefore, the start condition is, for example, when several sheets (or several pages) of images of the recording medium 200 have been recorded. Alternatively, it may be when the total number of ejections of the nozzle 31 (dot count value) reaches a specified value. Alternatively, it may be when a predetermined time has passed since the start of use of the liquid ejection device 1. If it is determined that the start condition is satisfied, the process proceeds to step S12.
[0067] In step S12, one nozzle 31 is selected from the multiple nozzles 31 to be inspected. In step S13, the ejection conditions are set. The ejection conditions set here are the same as those set during image recording. The settings here are the same as those set in step S3 of FIG. 10, except for the drive conditions of the energy generating elements 33.
[0068] In step S14, ink is ejected under the ejection conditions set in step S13. Here, the carriage 3 is moved so that the ejection head 3 passes over the droplet detection unit 7, and ink is ejected from the ejection head 3 during the movement. In step S15, a process is performed in which the droplet detection unit 7 detects the ink droplets ejected from the ejection head 3. The detection result of the droplet detection unit 7 is stored in the storage device 92 in association with the selected nozzle 31. The processes of steps S14 and S15 may be performed between recording operations (for example, between pages), or may be performed while the carriage 2 is moving in one recording scan operation.
[0069] In step S16, it is determined whether data acquisition has been completed for all of the multiple nozzles 31 to be inspected, and if not, the process returns to step S12 to select another nozzle 31 and perform the same process. If completed, the process proceeds to step S17.
[0070] In step S17, one nozzle 31 is selected from the multiple nozzles 31 to be inspected. In step S18, a discharge state value is calculated from the detection result stored in step S15 for the selected nozzle 31. In this embodiment, the amplitude ΔX, the change time ΔY, and the peak detection time ΔZ described with reference to FIG. 9(A) or FIG. 9(B) are calculated. In step S19, the reference values Δα, Δβ, and Δγ corresponding to the selected nozzle 31 are read from the storage device 92. In step S20, a process is performed in which the ΔX, ΔY, and ΔZ calculated in step S18 are compared with the reference values Δα, Δβ, and Δγ read in step S19. In step S21, based on the comparison result of step S18, it is determined whether the discharge performance of the target nozzle 31 has deteriorated (NG or not). If at least one of the difference between ΔX and Δα, the difference between ΔY and Δβ, and the difference between ΔZ and Δβ is less than a threshold value, it is determined to be NG. If it is determined that the result is not NG, the process proceeds to step S22, and if it is determined that the result is NG, the process proceeds to step S23.
[0071] In step S18, the droplet ejection speed and the droplet ejection amount may be compared. The droplet ejection speed can be calculated from ΔZ (or Δγ for the reference value). The droplet ejection amount can be calculated from ΔX and ΔY (or Δα and Δβ for the reference value).
[0072] In step S22, it is determined whether the performance degradation determination process (steps S18 to S19) has been completed for all nozzles 31 of the multiple nozzles 31 being inspected, and if not, the process returns to step S17 to select another nozzle 31 and perform the same process.
[0073] In step S23, a process for dealing with the performance degradation of the nozzle 31 is executed. One example of the process for dealing with the performance degradation of the nozzle 31 is a process for notifying the user that the performance degradation of the nozzle 31 has occurred. The notification can be performed, for example, by displaying on the display panel 13. The notification can also be in the form of a notification to the user via a network (notification to the host device 100). By such a notification, the user can be prompted to perform registration adjustment or density adjustment to correct the control parameters of the ejection head 3, or to replace the ejection head 3.
[0074] The corresponding process may also be a process of automatically adjusting registration or density, or a process of automatically moving the carriage 2 to move the ejection head 3 to the recovery unit 8, and recovering the ejection performance by the recovery unit 8.
[0075] The registration adjustment may be performed by recording a predetermined test pattern on a recording medium and adjusting the landing position based on the test pattern. The landing position adjustment may be performed by correcting the control parameters of the ejection head 3, such as the ejection timing (output timing of the ejection signal) and the ejection time (ON time of the ejection signal) of the nozzle 31. Alternatively, the height of the ejection head 3 may be adjusted by the lift motor 49.
[0076] As described above, in this embodiment, the fluctuation in the ejection performance of the nozzles 31 can be determined more appropriately without being affected by individual differences.
[0077] <Other embodiments> In the above embodiment, the droplet detection unit 7 is disposed outside the recording area of the image on the recording medium 200, but it may be disposed within the recording area. In this case, the droplet detection unit 7 may be disposed at a preliminary ejection port provided in the platen 6. The preliminary ejection port is an opening that receives ink droplets preliminarily ejected from the ejection head 7 to maintain ejection performance. By disposing a sensor equivalent to the droplet detection unit 7 within this opening, it is possible to shorten the moving distance of the carriage 2 when inspecting the nozzles 13. For example, when executing the process of FIG. 12 during a recording operation, it is only necessary to move the carriage 2 within the recording area, so that a decrease in throughput can be prevented.
[0078] In addition, in the above embodiment, a serial type recording device is exemplified in which the ejection head 3 moves with the movement of the carriage 2 to eject ink, but the present invention is also applicable to a full-line type recording device in which the ejection head 3 has a length equivalent to the width of the recording medium 200.
[0079] The present invention can also be realized by a process in which a program for realizing one or more functions of the above-mentioned embodiments is supplied to a system or device via a network or a storage medium, and one or more processors in a computer of the system or device read and execute the program. The present invention can also be realized by a circuit (e.g., ASIC) for realizing one or more functions. <Summary of the embodiment> The above embodiment discloses at least the following inventions.
[0080] Item 1. A detection means for detecting liquid discharged from the nozzle of the discharge head; A determination means for determining whether or not the ejection performance of the nozzle has deteriorated; A liquid ejection device comprising: the nozzle is provided with an energy generating element that generates energy for ejecting liquid, The determination means is determining whether or not the ejection performance of the nozzle has deteriorated by comparing a detection result of the detection means when the energy generating element is driven under a first driving condition with a reference value; The reference value is The energy generating element is driven under a second driving condition in which the energy is lower than that of the first driving condition, and the second driving condition is set based on a detection result of the detection means. A liquid ejection device comprising:
[0081] Item 2. The liquid ejection device according to item 1, a setting means for setting the reference value based on a detection result of the detection means when the driving is performed under the second driving condition when the first condition is established, and storing the set reference value in a storage means; The determination means is when a second condition different from the first condition is satisfied, a detection result of the detection means when driving is performed under the first driving condition is compared with the reference value read from the storage means to determine whether or not the ejection performance of the nozzle has deteriorated. A liquid ejection device comprising:
[0082] Item 3. Item 2. The liquid ejection device according to item 2, the second condition is a condition based on the number of times liquid is ejected from the nozzle; A liquid ejection device comprising:
[0083] Item 4. Item 2. The liquid ejection device according to item 2, The second condition is a condition based on the passage of time. A liquid ejection device comprising:
[0084] Item 5. Item 2. The liquid ejection device according to item 2, The first condition is a condition based on start of use of the liquid ejection device, replacement of the ejection head, adjustment of registration of an image recorded by ejecting the liquid, or adjustment of density of an image recorded by ejecting the liquid. A liquid ejection device comprising:
[0085] Item 6. A liquid ejection device according to any one of items 1 to 6, The detection means is A light emitting element and a light receiving element that receives light emitted by the light emitting element, Detecting the liquid passing through a detection position between the light emitting element and the light receiving element; A liquid ejection device comprising:
[0086] Item 7. Item 6. The liquid ejection device according to item 6, The determination means is comparing the liquid ejection speed and ejection amount based on the detection result with a reference value of the ejection speed and a reference value of the ejection amount as the reference values; A liquid ejection device comprising:
[0087] Item 8. A liquid ejection device according to any one of items 1 to 7, The ejection head includes: a plurality of first nozzles for ejecting a first type of liquid; a second plurality of nozzles for ejecting a second type of liquid; The reference value is a first reference value corresponding to the first plurality of nozzles; a second reference value corresponding to the second plurality of nozzles; A liquid ejection device comprising:
[0088] Item 9. A liquid ejection device according to any one of items 1 to 8, the energy generating element generates the energy when supplied with power; The first driving condition and the second driving condition have different durations of power supply to the energy generating element. A liquid ejection device comprising:
[0089] Item 10. A liquid ejection device according to any one of items 1 to 8, a notification means for notifying a user of the degradation in the ejection performance of the nozzle when the determination means determines that the ejection performance of the nozzle has deteriorated, A liquid ejection device comprising:
[0090] Item 11. A liquid ejection device according to any one of items 1 to 8, When the determination means determines that the ejection performance of the nozzle has deteriorated, a control parameter of the ejection head is corrected. A liquid ejection device comprising:
[0091] Item 12. A liquid ejection device according to any one of items 1 to 8, A recovery means for recovering the ejection performance of the nozzle is provided, when the determining means determines that the ejection performance of the nozzle has deteriorated, the recovering means recovers the ejection performance of the nozzle; A liquid ejection device comprising:
[0092] Item 13. A liquid ejection device according to any one of items 1 to 12, a carriage that carries the ejection head and moves, the detection means detects the liquid ejected from the nozzle while the carriage is moving; A liquid ejection device comprising:
[0093] Item 14. Item 14. The liquid ejection device according to item 13, the detection means detects the liquid ejected from the nozzle while the carriage is moving at a constant speed; A liquid ejection device comprising:
[0094] Item 15. A liquid ejection device according to any one of claims 1 to 14, The liquid ejection device is a recording device that ejects ink as the liquid onto a recording medium to record an image. A liquid ejection device comprising:
[0095] Item 16. Item 16. The liquid ejection device according to item 15, the first driving condition is a driving condition of the energy generating element when an image is recorded on the recording medium; A liquid ejection device comprising:
[0096] Item 17. A method for controlling a liquid ejection device comprising: an ejection head that ejects liquid; and a detection unit that detects liquid ejected from a nozzle of the ejection head, the nozzle being provided with an energy generating element that generates energy for ejecting the liquid, the method comprising the steps of: a determination step of determining whether or not the ejection performance of the nozzle has deteriorated by comparing a detection result of the detection means when the energy generating element is driven under a first drive condition with a reference value, The reference value is The energy generating element is driven under a second driving condition in which the energy is lower than that of the first driving condition, and the second driving condition is set based on a detection result of the detection means. A control method comprising:
[0097] Item 18. A storage medium storing a program for causing a computer to execute a control method for a liquid ejection device comprising an ejection head that ejects liquid and a detection means that detects the liquid ejected from a nozzle of the ejection head, the nozzle being provided with an energy generating element that generates energy for ejecting the liquid, the storage medium comprising: The control method includes: a determination step of determining whether or not the ejection performance of the nozzle has deteriorated by comparing a detection result of the detection means when the energy generating element is driven under a first drive condition with a reference value, The reference value is The energy generating element is driven under a second driving condition in which the energy is lower than that of the first driving condition, and the second driving condition is set based on a detection result of the detection means. A storage medium comprising:
[0098] Item 19. A program for causing a computer to execute a control method for a liquid ejection device comprising an ejection head that ejects liquid and a detection means that detects the liquid ejected from a nozzle of the ejection head, the nozzle being provided with an energy generating element that generates energy for ejecting the liquid, the program comprising: The control method includes: a determination step of determining whether or not the ejection performance of the nozzle has deteriorated by comparing a detection result of the detection means when the energy generating element is driven under a first drive condition with a reference value, The reference value is The energy generating element is driven under a second driving condition in which the energy is lower than that of the first driving condition, and the second driving condition is set based on a detection result of the detection means. A program characterized by:
[0099] 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]
[0100] 1 Liquid ejection device, 3 ejection head, 7 droplet detection unit, 31 nozzle, 33 energy generating element
Claims
1. A detection means for detecting liquid discharged from the nozzle of the discharge head; A determination means for determining whether or not the ejection performance of the nozzle has deteriorated; A liquid ejection device comprising: the nozzle is provided with an energy generating element that generates energy for ejecting liquid, The determination means is determining whether or not the ejection performance of the nozzle has deteriorated by comparing a detection result of the detection means when the energy generating element is driven under a first driving condition with a reference value; The reference value is The energy generating element is driven under a second driving condition in which the energy is lower than that of the first driving condition, and the second driving condition is set based on a detection result of the detection means. A liquid ejection device comprising:
2. The liquid ejection device according to claim 1 , a setting means for setting the reference value based on a detection result of the detection means when the driving is performed under the second driving condition when the first condition is established, and storing the set reference value in a storage means; The determination means is when a second condition different from the first condition is satisfied, a detection result of the detection means when driving is performed under the first driving condition is compared with the reference value read from the storage means to determine whether or not the ejection performance of the nozzle has deteriorated. A liquid ejection device comprising:
3. The liquid ejection device according to claim 2, the second condition is a condition based on the number of times liquid is ejected from the nozzle; A liquid ejection device comprising:
4. The liquid ejection device according to claim 2, The second condition is a condition based on the passage of time. A liquid ejection device comprising:
5. The liquid ejection device according to claim 2, The first condition is a condition based on start of use of the liquid ejection device, replacement of the ejection head, adjustment of registration of an image recorded by ejecting the liquid, or adjustment of density of an image recorded by ejecting the liquid. A liquid ejection device comprising:
6. The liquid ejection device according to claim 1 , The detection means is A light emitting element and a light receiving element that receives light emitted by the light emitting element, Detecting the liquid passing through a detection position between the light emitting element and the light receiving element; A liquid ejection device comprising:
7. The liquid ejection device according to claim 6, The determination means is comparing the liquid ejection speed and ejection amount based on the detection result with a reference value of the ejection speed and a reference value of the ejection amount as the reference values; A liquid ejection device comprising:
8. The liquid ejection device according to claim 1 , The ejection head includes: a plurality of first nozzles for ejecting a first type of liquid; a second plurality of nozzles for ejecting a second type of liquid; The reference value is a first reference value corresponding to the first plurality of nozzles; a second reference value corresponding to the second plurality of nozzles; A liquid ejection device comprising:
9. The liquid ejection device according to claim 1 , the energy generating element generates the energy when supplied with power; The first driving condition and the second driving condition have different durations of power supply to the energy generating element. A liquid ejection device comprising:
10. The liquid ejection device according to claim 1 , a notification means for notifying a user of the degradation in the ejection performance of the nozzle when the determination means determines that the ejection performance of the nozzle has deteriorated, A liquid ejection device comprising:
11. The liquid ejection device according to claim 1 , When the determination means determines that the ejection performance of the nozzle has deteriorated, a control parameter of the ejection head is corrected. A liquid ejection device comprising:
12. The liquid ejection device according to claim 1 , A recovery means for recovering the ejection performance of the nozzle is provided, when the determining means determines that the ejection performance of the nozzle has deteriorated, the recovering means recovers the ejection performance of the nozzle; A liquid ejection device comprising:
13. The liquid ejection device according to claim 1 , a carriage that carries the ejection head and moves, the detection means detects the liquid ejected from the nozzle while the carriage is moving; A liquid ejection device comprising:
14. The liquid ejection device according to claim 13, the detection means detects the liquid ejected from the nozzle while the carriage is moving at a constant speed; A liquid ejection device comprising:
15. The liquid ejection device according to claim 1 , The liquid ejection device is a recording device that ejects ink as the liquid onto a recording medium to record an image. A liquid ejection device comprising:
16. The liquid ejection device according to claim 15, the first driving condition is a driving condition of the energy generating element when an image is recorded on the recording medium; A liquid ejection device comprising:
17. A method for controlling a liquid ejection device comprising an ejection head that ejects liquid and a detection unit that detects liquid ejected from a nozzle of the ejection head, the nozzle being provided with an energy generating element that generates energy for ejecting the liquid, the method comprising the steps of: a determination step of determining whether or not the ejection performance of the nozzle has deteriorated by comparing a detection result of the detection means when the energy generating element is driven under a first drive condition with a reference value, The reference value is The energy generating element is driven under a second driving condition in which the energy is lower than that of the first driving condition, and the second driving condition is set based on a detection result of the detection means. A control method comprising:
18. A storage medium storing a program for causing a computer to execute a control method for a liquid ejection device comprising an ejection head that ejects liquid and a detection means that detects the liquid ejected from a nozzle of the ejection head, the nozzle being provided with an energy generating element that generates energy for ejecting the liquid, the storage medium comprising: The control method includes: a determination step of determining whether or not the ejection performance of the nozzle has deteriorated by comparing a detection result of the detection means when the energy generating element is driven under a first drive condition with a reference value, The reference value is The energy generating element is driven under a second driving condition in which the energy is lower than that of the first driving condition, and the second driving condition is set based on a detection result of the detection means. A storage medium comprising:
19. A program for causing a computer to execute a control method for a liquid ejection device comprising an ejection head that ejects liquid and a detection means that detects the liquid ejected from a nozzle of the ejection head, the nozzle being provided with an energy generating element that generates energy for ejecting the liquid, the program comprising: The control method includes: a determination step of determining whether or not the ejection performance of the nozzle has deteriorated by comparing a detection result of the detection means when the energy generating element is driven under a first drive condition with a reference value, The reference value is The energy generating element is driven under a second driving condition in which the energy is lower than that of the first driving condition, and the second driving condition is set based on a detection result of the detection means. A program characterized by: