JP7424094B2 - Liquid discharge device, its control method and program - Google Patents

Description

The present invention relates to a liquid ejection device, a control method thereof, and a program.

As a conventional liquid ejecting device, a liquid ejecting device disclosed in Patent Document 1 is known. This liquid ejecting device generates a plurality of micro-vibration drive signals based on the characteristics and type of ink. In response to this micro-vibration drive signal, the meniscus in the nozzle opening of the head is slightly vibrated to prevent the ink in the nozzle from thickening.

Japanese Patent Application Publication No. 2001-341326

By the way, in the case of a liquid discharging device that supplies liquid from a fixedly arranged tank to a head on a carriage through piping, it is known in this application that when the head moves, the pressure of the liquid in the head changes accordingly. discovered by the inventor of On the other hand, in the liquid ejecting device described above, such pressure changes are not taken into consideration when causing the meniscus to vibrate slightly. Therefore, if micro-vibration control is performed when the pressure of the liquid in the head increases as the head moves, there is a risk that the liquid will be ejected from the nozzle opening.

In view of this situation, it is an object of the present invention to provide a liquid ejection device, a control method thereof, and a program that can more reliably execute non-ejection driving.

A liquid ejecting device according to an aspect of the present invention includes: a tank that stores a liquid; a head that ejects the liquid; a pipe that communicates the tank and the head to supply the liquid to the head; a scanning mechanism that moves the head in the scanning direction independently of the controller; and a control section, the control section performs a movement process of accelerating the head, moving it at a constant speed, and then decelerating it; Waveform generation for generating a plurality of types of non-discharge drive waveforms that vibrate the liquid so as not to discharge the liquid during at least one of the speed changes according to the pressure of the liquid in the head during the speed change. Process and execute.

A method for controlling a liquid ejection device according to an aspect of the present invention includes: a tank for storing liquid; a head for ejecting the liquid; and a pipe for communicating the tank and the head to supply the liquid to the head. , a control method for a liquid ejecting apparatus comprising: a scanning mechanism that moves the head in a scanning direction independently from the tank; and a control section, the control section accelerating the head and then moving the head at a constant speed. A movement process in which the liquid is decelerated after the movement, and a non-ejection drive waveform in which the liquid is vibrated so as not to be ejected during at least one of the acceleration and deceleration, are applied to the head during the speed change. A waveform generation process is performed in which a plurality of types of waveforms are generated depending on the pressure of the liquid.

A program according to an aspect of the present invention includes a tank that stores a liquid, a head that discharges the liquid, a pipe that communicates between the tank and the head and supplies the liquid to the head, and a pipe that is independent of the tank. a scanning mechanism that moves the head in a scanning direction, and a control unit, a moving process that accelerates the head, moves the head at a constant speed, and then decelerates the head, and the acceleration and the deceleration. Waveform generation processing that generates a plurality of types of non-discharge drive waveforms that vibrate the liquid so as not to discharge the liquid during at least one of the speed changes, depending on the pressure of the liquid in the head during the speed change; , execute.

The present invention has the effect of providing a liquid ejection device having the above configuration and capable of more reliably performing non-ejection driving, a control method thereof, and a program.

The above objects, other objects, features, and advantages of the present invention will become apparent from the following detailed description of preferred embodiments with reference to the accompanying drawings.

1 is a schematic diagram of a liquid ejection device according to an embodiment of the present invention viewed from above. FIG. 2 is a cross-sectional view schematically showing the head of FIG. 1; FIG. 2 is a functional block diagram showing the configuration of the liquid ejection device of FIG. 1. FIG. FIGS. 4A and 4B are graphs showing the relationship between the liquid head difference and time during the printing process. FIG. 5(a) is a diagram schematically showing a non-ejection waveform. FIGS. 5(b) to 5(d) are tables showing times in the non-ejection waveform of FIG. 5(a). 2 is a flowchart illustrating an example of a method of controlling the liquid ejection device of FIG. 1. FIG. FIG. 7(a) is a table showing the relationship between liquid temperature and profile correction coefficient. FIG. 7(b) is a table showing the relationship between the usage period of the tank and the profile correction coefficient. FIG. 7(c) is a table showing the relationship between liquid viscosity and profile correction coefficient. FIG. 7(d) is a table showing the relationship between the surface tension of the liquid and the profile correction coefficient. FIG. 7E is a table showing the relationship between the ejection duty and the ratio of the number of non-ejection drives. FIG. 7F is a table showing the relationship between the liquid temperature and the ratio of the number of non-discharge drives. FIG. 8(a) is a flowchart showing an example of a method for controlling a liquid ejecting device according to Modifications 2 to 5 of the embodiment of the present invention. FIG. 8(b) is a flowchart illustrating an example of a method for controlling a liquid ejection device according to Modifications 6 and 7 of the embodiment of the present invention.

Embodiments of the present invention will be specifically described below with reference to the drawings. In addition, below, the same reference numerals are given to the same or equivalent element throughout all the drawings, and the overlapping explanation will be omitted.

<Configuration of image recording device>
As shown in FIG. 1, a liquid ejecting device 10 according to an embodiment of the present invention is a device that ejects liquid such as ink, and is, for example, an inkjet printer. The liquid ejection device 10 employs a serial head system and includes a housing 11, a head unit 12, a platen 13, a transport mechanism 14, a scanning mechanism 15, a tank 16, and a control section 20. The housing 11 accommodates each part of the liquid ejection device 10.

The head unit 12 includes a carriage 12a and a head 30. The head 30 is mounted on the carriage 12a and reciprocates in the scanning direction together with the carriage 12a. The head 30 includes a drive element 32 (FIG. 2) and a nozzle 33, and discharges liquid from the nozzle 33 by driving the drive element 32. The plurality of nozzles 33 are opened on the lower surface of the head 30 and are arranged in the transport direction to form a plurality of (for example, four) nozzle rows. Note that the details of the head 30 will be described later.

The platen 13 is a flat plate member, and the recording medium D is placed on the upper surface thereof. The platen 13 determines the distance between the recording medium D and the lower surface of the head 30 provided opposite thereto. Note that the head 30 side with respect to the platen 13 is referred to as the upper side, and the opposite side is referred to as the lower side, but the arrangement of the liquid ejection device 10 is not limited to this.

The transport mechanism 14 includes, for example, two transport rollers 14a and a transport motor 14b (FIG. 2). The two conveyance rollers 14a are arranged parallel to each other so that the platen 13 is sandwiched in the conveyance direction, and their rotation axes extend in the scanning direction. The conveyance roller 14a is connected to a conveyance motor 14b, rotates when driven by the conveyance motor 14b, and conveys the recording medium D on the platen 13 in the conveyance direction.

The scanning mechanism 15 is a mechanism for reciprocating the head 30 in the scanning direction, and includes, for example, two guide rails 15a, a scanning motor 15b (FIG. 2), an endless belt, and the like. The carriage 12a of the head unit 12 is supported by two guide rails 15a and fixed to an endless belt. When the scanning motor 15b is driven, an endless belt connected to the scanning motor 15b runs. Thereby, the carriage 12a reciprocates within a predetermined scanning range in the scanning direction along the guide rail 15a.

For example, the tanks 16 are fixedly arranged in the housing 11 and are provided for each type of liquid. For example, there are four tanks 16, each storing black, yellow, cyan, and magenta liquids. Each tank 16 is connected to the head 30 by a pipe 16a, and the pipe 16a communicates the tank 16 and the head 30 to supply liquid to the head 30. Note that even if the tank 16 is a cartridge that can be detached from the housing 11, the tank 16 is attached to the housing 11 during printing processing and is fixedly disposed on the housing 11. Therefore, the scanning mechanism 15 moves the head 30 in the scanning direction independently of the tank 16. The pipe 16a is made of flexible resin or the like, and deforms as the head 30 moves relative to the tank 16.

<Head configuration>
The head 30 has a flow path forming body 31, a driving element 32, and a diaphragm 34, as shown in FIG. The channel forming body 31 is a stacked body of a plurality of plates, and holes and grooves of various sizes are formed in each plate. In the stacked body in which each plate is stacked, holes and grooves are combined to form a plurality of channels. The flow path includes a plurality of nozzles 33, a plurality of individual flow paths (channels), and a manifold 35.

The nozzle 33 opens on the lower surface of the flow path forming body 31. The openings (nozzle holes 33a) of the plurality of nozzles 33 are lined up in the transport direction to form a nozzle row, and four nozzle lines are lined up in the scanning direction. Each nozzle row corresponds to ink of a mutually different color (for example, black, yellow, cyan, and magenta). Note that the plurality of nozzles 33 may be arranged in a direction intersecting the conveyance direction. Further, the nozzle rows may be arranged in a direction intersecting the scanning direction.

The manifold 35 extends in the transport direction and has a supply port at its end. The supply port is connected to the tank 16 (FIG. 1) via piping 16a or the like. The individual flow path extends from the manifold 35 to the nozzle 33, and has a throttle flow path 36, a pressure chamber 37, and a communication flow path 38 therebetween, which are connected in this order.

In such a configuration, the liquid flows from the tank 16 through the pipe 16a and the like, and flows into the manifold 35 via the supply port. While flowing through the manifold 35, the liquid enters each of the plurality of individual channels. In the individual channels, the liquid flows through the throttle channel 36, the pressure chamber 37, and the communication channel 38 in this order, and flows into the nozzle 33.

The diaphragm 34 is arranged on the flow path forming body 31 and covers the upper opening of the pressure chamber 37. The drive element 32 is, for example, a piezoelectric element, includes a common electrode 32a, a piezoelectric layer 32b, and individual electrodes 32c, and is arranged on the diaphragm 34.

When a signal from the control unit 20 (FIG. 1) is applied to the individual electrode 32c, the piezoelectric layer 32b expands and contracts in the plane direction together with the two electrodes 32a and 32c. The diaphragm 34 deforms in cooperation with the drive element 32 to change the volume of the pressure chamber 37. As a result, pressure is applied to the liquid in the pressure chamber 37. This causes the meniscus of the nozzle hole 33a to vibrate and liquid to be discharged from the nozzle hole 33a.

<Configuration of control device>
As shown in FIG. 3, the control unit 20 includes an interface (I/F 21), a CPU 22, a ROM 23, a RAM 24, and an ASIC 25 (Application Specific Integrated Circuit). The I/F 21 receives various data such as print data from external devices E such as computers, cameras, networks, and storage media. The print data includes data indicating an image to be printed on the recording medium D and data indicating conditions for printing the image.

The RAM 24 temporarily stores various data. Examples of the various data include print data and data converted by the control unit 20. The ROM 23 stores programs for controlling each part. Note that the program may be acquired from the external device E via the I/F 21, or may be stored in another storage medium.

The ASIC 25 has drive circuits 26 to 28 that drive each part, and is electrically connected to a head driver IC 40, a scan driver IC 41, and a transport driver IC 42. By executing the program stored in the ROM 23, the CPU 22 causes at least one of the CPU 22 and the ASIC 25 to control the head 30, the conveyance motor 14b, and the scanning motor 15b using each of the driver ICs 40 to 42, thereby performing various printing processes and other operations. Perform processing. Note that details of the printing process will be described later.

The head drive circuit 26 has a waveform generator 26a. The waveform generation unit 26a generates a waveform that defines the drive (ejection drive, non-ejection drive) of the drive element 32. The waveform includes an ejection waveform and a non-ejection waveform. The non-ejection waveform is a waveform for non-ejection driving that vibrates the meniscus of the nozzle hole 33a so that liquid is not ejected from the nozzle hole 33a, and has multiple types of signals depending on the magnitude of the vibration of the meniscus. ing. Details of this non-ejection drive will be described later.

Further, the ejection waveform is a waveform for ejection driving to eject liquid from the nozzle hole 33a based on the print data, and has multiple types of signals depending on the amount of liquid for each drop based on the print data. ing. For example, the ejection waveform includes a medium droplet ejection waveform that ejects a first amount of liquid, a large droplet ejection waveform that ejects a second amount of liquid that is larger than the first amount, and a large droplet ejection waveform that ejects a second amount of liquid that is larger than the first amount. There is an ejection waveform for small droplets that ejects a small third amount of liquid.

Note that the waveform generation unit 26a may be hardware such as a logic circuit, or may be realized by the CPU 22 executing software. Further, the waveform generation unit 26a may be a memory in which waveforms are stored in advance. In this case, the head drive circuit 26 generates a waveform by acquiring the waveform from the waveform generation unit 26a based on the print data.

Further, the head drive circuit 26 selects one type of waveform from a plurality of types of waveforms for each nozzle 33 and each drive cycle according to print data, and generates a selection command. The head drive circuit 26 is connected to the head driver IC 40 and outputs a waveform and its selection command to the head driver IC 40.

The head driver IC 40 is connected to the drive element 32. The head driver IC 40 converts the waveform and selection command into a drive signal, and outputs the drive signal to the drive element 32. When the drive element 32 is driven by the drive signal, the volume of the pressure chamber 37 in the head 30 changes, and pressure is applied to the liquid in the nozzle 33 communicating with the pressure chamber 37.

Here, according to the non-ejection drive signal based on the non-ejection waveform, the drive element 32 executes the non-ejection drive, and the meniscus of the nozzle hole 33a communicating with the pressure chamber 37 vibrates slightly. Further, according to the ejection drive signal based on the ejection waveform, the drive element 32 executes ejection drive, and an amount of liquid corresponding to the print data is ejected from the nozzle hole 33a.

The scan drive circuit 27 outputs control data according to print data to the scan driver IC 41. The scan driver IC 41 outputs a drive signal according to the control data to the scan motor 15b, and controls the drive of the scan motor 15b. Further, the transport drive circuit 28 outputs control data corresponding to the print data to the transport driver IC 42. The transport driver IC 42 outputs a drive signal according to the control data to the transport motor 14b, and controls the drive of the transport motor 14b. As a result, the drive timing, rotation speed, rotation amount, etc. of the scanning motor 15b and the transport motor 14b are controlled.

<Print processing>
The control unit 20 controls the scanning motor 15b based on the print data, and executes a movement process in which the head 30 is accelerated, moved at a constant speed, and then decelerated. During this speed change of acceleration and deceleration, the control unit 20 causes the drive element 32 to perform non-discharge drive, which will be described later. Further, during the constant speed movement, the control unit 20 causes the drive element 32 to perform a discharge drive to discharge the liquid from the nozzle 33 . This ejected liquid forms dots (images) on the recording medium D placed on the platen 13.

The control unit 20 also controls the transport motor 14b based on the print data to transport the recording medium D by a predetermined amount in the transport direction. The printing operation is continued by alternately repeating the recording operation including the scanning operation and the ejection operation and the conveyance operation as one pass. Through this recording operation, dots are formed in the scanning direction by the ejected liquid, and an image (pass image) is formed on the recording medium D. Subsequently, the recording medium D is moved in the transport direction with respect to the head 30 by the transport operation. By repeating this alternately, the pass images are lined up in the transport direction, and an image corresponding to the print data is formed on the recording medium D.

Note that the printing process may be unidirectional printing (one-sided printing) in which the ejection operation is performed when the head 30 moves to one side in the scanning direction, or the printing process may be unidirectional printing (one-sided printing) in which the head 30 moves to one side in the scanning direction and the other side in the scanning direction. Bidirectional printing may be used, in which the ejection operation is performed when the printer moves to the printer. In the case of unidirectional printing, the starting side of the recording operation is constant on one side in the scanning direction, but in the case of bidirectional printing, the starting side of the recording operation alternates on both sides of the scanning direction.

<Non-discharge drive>
When the head 30 moves in the scanning direction with respect to the tank 16 due to the scanning operation of the printing process, the pressure of the liquid within the head 30 changes as the head 30 moves. FIG. 4 is a graph showing the relationship between the water head difference of the liquid and time during the printing process. In FIG. 4, the horizontal axis shows time, and the vertical axis shows the difference in liquid head. Since the moving speed of the head 30 is controlled by the control unit 20, the time in FIG. 4 corresponds to the position of the head 30. Here, the water head is the fluid energy (generally, the sum of pressure energy, kinetic energy, and potential energy, and here mainly pressure energy) possessed by the liquid in the head 30. The water head difference shown in FIG. 4 indicates the difference between the water head of the liquid in the head 30 during the scanning operation and the reference water head when the water head of the liquid in the stopped head 30 is used as a reference. .

In this way, the water head difference changes during acceleration and deceleration speed changes, and remains constant during constant speed movement. The pressure applied to the liquid in the nozzle hole 33a changes due to this change in the water head difference. If the meniscus of the nozzle hole 33a vibrates due to non-discharge drive while this applied pressure is increasing, liquid is likely to be discharged from the nozzle hole 33a. On the other hand, if the meniscus of the nozzle hole 33a vibrates due to non-ejection drive while the applied pressure is decreasing, the meniscus is cut and air bubbles are likely to enter the nozzle 33.

Therefore, the control unit 20 uses a non-discharge drive waveform (non-discharge waveform) that vibrates the liquid so as not to discharge the liquid during at least one of acceleration and deceleration to change the pressure of the liquid in the head 30 during the shift. Executes waveform generation processing that generates multiple types of waveforms depending on the situation. Note that generation of a non-ejection waveform for executing non-ejection drive during both acceleration and deceleration speed change will be described below. However, a non-ejection waveform may be generated in order to perform non-ejection drive during either acceleration or deceleration. For example, if the speed of movement to one side in the scanning direction is higher than the speed of movement to the other side, multiple types of non-ejection waveforms are generated during the speed change when moving to one side, and when moving to the other side. One type of non-ejection waveform may be generated during the speed change.

Specifically, a profile showing the relationship between the moving time of the head 30 and the water head difference (pressure) shown in FIG. 4 is obtained in advance through experiments, simulations, etc., and is stored in the ROM 23. This profile changes such that as the moving speed of the head 30 increases, the water head difference increases. For example, in FIG. 4(b), the moving speed is greater than in FIG. 4(a), so the water head difference is greater than in FIG. 4(a). Therefore, the control unit 20 obtains the moving speed of the head 30 based on the print data, and obtains from the ROM 23 a profile corresponding to the moving speed.

Based on this profile, the control unit 20 generates a non-ejection waveform in response to pressure changes. In a range where the pressure change is large, liquid ejection and meniscus breakage are likely to occur, so a non-ejection waveform is generated in which the amount of vibration of the meniscus due to non-ejection drive is small. On the other hand, in a range where the pressure change is small, ejection and meniscus breakage are difficult to occur, so a non-ejection waveform is generated in which the amount of vibration of the meniscus due to non-ejection driving is large. This increases the amount of liquid spread in the nozzle 33 and improves suppression of thickening of the liquid in the nozzle 33.

For example, the non-ejection waveform is a pulse signal and has the shape shown in FIG. 5(a). The vertical axis in FIG. 5(a) indicates voltage, and the horizontal axis indicates time. For example, the non-ejection waveform has two trapezoidal peaks (first peak p1 and second peak p2) that rise from the reference voltage to a predetermined voltage and return to the reference voltage.

As shown in FIG. 5B, there are five types of non-ejection waveforms (first to fifth non-ejection waveforms) depending on the amount of vibration of the meniscus due to non-ejection driving. For example, these non-ejection waveforms include a time t1 during which the voltage rises from the reference voltage of the first peak p1 and returns to the reference voltage, a time t2 between the first peak p1 and the second peak p2, and a time t2 between the first peak p1 and the second peak p2. It is set by the time t3 during which the voltage rises from the reference voltage of 2 peaks p2 until it returns to the reference voltage. In the chart shown in FIG. 5(b), data regarding the first to fifth non-ejection waveforms are arranged vertically in this order, and data regarding times t1 to t3 for each non-ejection waveform are arranged horizontally in this order. . The same applies to FIGS. 5(c) and 5(d), which will be described later.

In FIG. 5B, in the first to fifth non-ejection waveforms, the time t1 of the first peak p1 and the time t3 of the second peak p2 are changed without changing the interval time t2. The longer the times t1 and t2, the greater the amount of vibration of the meniscus due to non-ejection driving.

For example, the times t1 and t3 of the fifth non-ejection waveform are 0.9 μs, which are longer than the times t1 and t3 of the first non-ejection waveform, which are 0.5 μs. Therefore, the amount of vibration of the meniscus due to the fifth non-ejection waveform is larger than the amount of vibration of the meniscus due to the first non-ejection waveform. Therefore, in a range where the pressure change is small, the fifth non-ejection waveform is generated, and in a range where the pressure change is large, the first non-ejection waveform is generated. Thereby, thickening of the liquid in the nozzle 33 can be suppressed while suppressing ejection and meniscus breakage.

Note that the method of setting the first to fifth non-ejection waveforms is not limited to the method shown in FIG. 5(b). For example, as in the example of FIG. 5C, in the first to fifth non-ejection waveforms, the time t2 may be changed without changing the times t1 and t3. In this case, the shorter the time t2, the greater the amount of vibration of the meniscus due to non-ejection driving. For example, the time t2 of the fifth non-ejection waveform is 10.0 μs, which is shorter than the time t2 of the first non-ejection waveform, which is 10.8 μs. Therefore, the amount of vibration caused by the fifth non-ejection waveform is larger than the amount of vibration caused by the first non-ejection waveform.

Furthermore, as in the example of FIG. 5(d), in the first to fifth non-ejection waveforms, the time t3 may be changed without changing the times t1 and t2. In this case, the longer the time t3, the greater the amount of vibration of the meniscus due to non-ejection driving. For example, the time t3 of the fifth non-ejection waveform is 0.9 μs, which is longer than the time t3 of the first non-ejection waveform, which is 0.5 μs. Therefore, the amount of vibration caused by the fifth non-ejection waveform is larger than the amount of vibration caused by the first non-ejection waveform.

<Control method of liquid ejection device>
The method of controlling the liquid ejection device 10 is executed, for example, according to the flowchart shown in FIG. First, upon acquiring print data (step S1), the control unit 20 determines the moving speed of the head 30 from the print data.

The control unit 20 acquires a profile indicating the relationship between the time during which the head 30 moves and the water head difference according to the moving speed (step S2). The relationship between this moving speed and the profile is predetermined.

Then, as shown in FIG. 4A, the control unit 20 divides the time during gear shifting into a plurality of predetermined time periods in the profile, and executes the division process. For example, as shown in FIG. 4(a), the time during gear change (deceleration, acceleration) is divided into three time periods a1, a2, and a3.

The control unit 20 acquires a representative value of pressure based on the profile and executes the acquisition process (step S3). Here, the control unit 20 calculates the rate of change in pressure with respect to time in each time period based on the profile. Since this ratio changes depending on the time in each time period, the control unit 20 calculates a plurality of ratios in each time period, and from these calculates representative values such as the average value, median value, and mode as a representative value of the pressure. Get it as a value.

In the waveform generation process, the control unit 20 generates a waveform for non-ejection drive according to the representative value of pressure (step S4). The relationship between this representative value and the waveform is determined in advance. For example, in time period a1, since the rate of change in pressure is small, a fifth non-ejection waveform is generated in which the amount of vibration of the meniscus due to non-ejection drive is large. Furthermore, in the time period a2, the rate of change is larger than in the time period a1, so the first non-ejection waveform is generated with an amount of vibration smaller than the amount of vibration of the meniscus based on the fifth non-ejection waveform. Furthermore, in time period a3, the rate of change is the same as in time period a1, so a fifth non-ejection waveform is generated.

In this manner, the control unit 20 generates a non-ejection waveform for non-ejection drive, and also generates an ejection waveform for ejection drive based on print data. Then, the control unit 20 generates a selection command to allocate a waveform to the nozzle 33 and the drive cycle, and outputs the waveform and selection command to the head driver IC 40. Further, the control unit 20 outputs control data to the scanning driver IC 41 and the transport driver IC 42. As a result, the drive element 32, scanning motor 15b, and transport motor 14b are driven.

Then, while the head 30 is moving at a constant speed, the drive element 32 performs ejection driving, and an image is formed on the recording medium D. Furthermore, during the speed change of the head 30, the drive element 32 performs non-ejection driving, causing the meniscus of the nozzle hole 33a to vibrate slightly. Thereby, the liquid in the nozzle 33 is stirred, and thickening of the liquid is suppressed. At this time, in the time period a2 where the rate of pressure change is large, non-ejection drive in which the amount of vibration of the meniscus is small is executed by the non-ejection drive signal based on the first non-ejection waveform. This suppresses liquid discharge and meniscus breakage.

In this way, in the liquid ejection device 10, the control unit 20 controls the waveform of the non-ejection drive that vibrates the liquid so as not to eject the liquid during at least one of acceleration and deceleration to the head 30 during the speed change. Multiple types are generated depending on the pressure of the liquid. This makes it possible to suppress ejection and meniscus breakage, and to reduce thickening of the liquid, by non-ejection driving in response to changes in liquid pressure in the head 30 during speed change.

In addition, in the profile showing the relationship between the time during which the head 30 moves and the pressure, the control unit 20 performs a division process of dividing the time during gear shifting into a plurality of time periods, and an acquisition process of obtaining a representative value of the pressure in the time period. A non-ejection driving waveform is generated according to the representative value in the waveform generation process. As a result, even if the pressure changes over time during gear shifting, a non-discharge drive waveform is generated in accordance with this change, so that the non-discharge drive more reliably prevents liquid discharge and meniscus breakage. can be executed.

Further, the control unit 20 generates a non-ejection drive waveform in which the vibration of the liquid is smaller in the waveform generation process as the rate of change in pressure with respect to time is larger. If the rate of change is large and liquid ejection and meniscus rupture are likely to occur, by reducing the vibration of the meniscus, non-ejection driving can be performed more reliably to prevent liquid ejection and meniscus rupture.

<Modification 1>
In the liquid ejecting device 10 according to the first modification, the control unit 20 increases the number of time divisions in the division process in the profile as the speed range that changes during the shift in the movement process increases.

Specifically, the larger the speed range that changes during the shift, the greater the amount of change in the liquid pressure in the head 30 during the shift. FIG. 4(b) is a profile when the moving speed of the head 30 is higher than in the case of FIG. 4(a), and the speed range that changes during shifting is wide. In FIG. 4(b), the amount of change in the water head difference (pressure) during gear shifting is larger than in FIG. 4(a). For example, the difference (amount of pressure change) between the pressure at the start of deceleration and the pressure at the end of acceleration is larger in FIG. 4(b) than in FIG. 4(a).

In this case, the control unit 20 divides the time during gear shifting into three time periods a1, a2, and a3 for the profile shown in FIG. 4(a). On the other hand, the control unit 20 divides the time during gear shifting into five time periods b1, b2, b3, b4, and b5 for the profile shown in FIG. 4(b).

The control unit 20 calculates the rate of change in pressure with respect to time in each time period, and generates a non-ejection drive waveform according to this rate. For example, in time periods b1 and b5, the rate of change in pressure is small, so a fifth non-ejection waveform is generated in which the amount of vibration of the meniscus due to non-ejection drive is large. In the time period b2, the rate of change is greater than in the time period b1, so a fourth non-ejection waveform with a vibration amount smaller than the meniscus vibration amount based on the fifth non-ejection waveform is generated. Furthermore, in the time period b3, since the rate of change is greater than in the time period b2, a third non-ejection waveform with a vibration amount smaller than the meniscus vibration amount based on the fourth non-ejection waveform is generated. In the time period b4, the rate of change is smaller than in the time period b3, so a second non-ejection waveform with a vibration amount smaller than the meniscus vibration amount based on the third non-ejection waveform is generated.

The control unit 20 outputs each non-ejection waveform and selection command to the head driver IC 40, thereby causing the head driver IC 40 to drive the drive element 32. As a result, the meniscus of the nozzle hole 33a in the head 30 vibrates slightly, the liquid is stirred in the nozzle 33, and thickening of the liquid is suppressed. At this time, in time periods b2 to b4 where the rate of pressure change is large, non-ejection drive is performed in which the amount of vibration of the meniscus is small according to the rate. In this way, the larger the speed range, the larger the pressure change, so by increasing the number of time divisions, it is possible to generate a non-ejection drive waveform that more appropriately corresponds to the pressure.

<Modification 2>
In the liquid ejection device 10 according to the second modification, the control unit 20 executes a correction process for correcting the profile so that the higher the temperature of the liquid, the larger the rate of change.

Specifically, as shown in FIG. 2, the liquid ejection device 10 includes a temperature sensor 39. The temperature sensor 39 is a sensor that detects the temperature of the liquid in the nozzle 33 in the head 30, and is provided in the head 30, for example.

The control unit 20 acquires a profile based on the print data and also acquires the temperature of the liquid from the temperature sensor 39. Then, between steps S2 and S3 of the flowchart shown in FIG. 8(a), the control unit 20 corrects the profile so that the higher the temperature of the liquid, the larger the rate of change, and executes the correction process ( Step S5). For example, FIG. 7(a) shows the relationship between the liquid temperature and the profile correction coefficient. The higher the temperature of the liquid, the larger the correction coefficient for the head difference (pressure) of the profile.

If the temperature of the liquid is within a predetermined temperature range including room temperature, the correction coefficient is 1. The control unit 20 multiplies the pressure of the profile obtained in step S2 by a correction coefficient of 1 to correct the profile. Then, the control unit 20 acquires a representative value of pressure based on the corrected profile (step S3), and selects multiple types of non-discharge drive waveforms in which the vibration of the liquid is smaller as the rate of change in pressure with respect to time is larger. Generate (step S4).

Further, if the temperature of the liquid is in a low temperature range lower than the predetermined temperature range, the correction coefficient is 0.9. In this case, since the temperature of the liquid is low, the viscosity of the liquid is high, the meniscus is less likely to vibrate, and the liquid is less likely to be ejected and the meniscus is less likely to break due to non-ejecting drive. Therefore, in step S5, the control unit 20 multiplies the profile pressure by a correction coefficient of 0.9 to correct the profile pressure. This reduces the rate of change in pressure, so the control unit 20 generates a non-discharge drive waveform in which the vibration of the liquid is larger than when the liquid is within the predetermined temperature range. As a result, in a state where liquid ejection and meniscus breakage are difficult to occur, the meniscus can be greatly vibrated to diffuse the liquid and reduce viscosity increase.

On the other hand, if the temperature of the liquid is in a high temperature range higher than the predetermined temperature range, the correction coefficient is 1.1. In this case, since the temperature of the liquid is high, the viscosity of the liquid is low, the meniscus is likely to vibrate, and the liquid is likely to be ejected due to non-ejecting drive and the meniscus may be broken. Therefore, in step S5, the control unit 20 multiplies the profile pressure by a correction coefficient of 1.1 to correct the profile pressure. This increases the rate of change in pressure, so the control unit 20 generates a non-ejection drive waveform in which the vibration of the liquid is smaller than when the liquid is within the predetermined temperature range. Thereby, the meniscus can be slightly vibrated to spread the liquid and reduce viscosity increase while suppressing ejection of the liquid and breakage of the meniscus.

<Modification 3>
In the liquid ejection device 10 according to the third modification, the tank 16 is replaceable. The liquid ejecting device 10 includes a counting section that counts the usage period of the tank 16. The control unit 20 executes a correction process for correcting the profile so that the shorter the period of use of the tank 16, the greater the rate of change. In addition, although the control part 20 is demonstrated below as a counting part which counts the usage period of the tank 16, the counting part may be provided separately from the control part 20.

Specifically, the tank 16 shown in FIG. 1 is a cartridge that can be attached to and removed from the housing 11. As shown in FIG. 2, the liquid ejecting device 10 is provided with a tank sensor 16b that detects replacement of the tank 16. For example, the tank sensor 16b may be a sensor that detects the presence or absence of the tank 16. In this case, the control unit 20 can determine that the tank 16 has been replaced when it detects that the tank 16 has changed from the absence state to the presence state based on the detection signal from the tank sensor 16b. Further, the tank sensor 16b may be a sensor that detects the amount of liquid in the tank 16. When the control unit 20 detects that the amount of liquid in the tank 16 has increased based on the detection signal from the tank sensor 16b, it can determine that the tank 16 has been replaced.

When replacement of the tank 16 is detected by the tank sensor 16b, the control unit 20 counts the time elapsed since the replacement as the period of use of the tank 16, and stores this period of use in a RAM or the like. Then, between steps S2 and S3 of the flowchart shown in FIG. 8A, the control unit 20 corrects the profile so that the shorter the usage period of the tank 16, the larger the rate of change, and executes the correction process. (Step S5). For example, FIG. 7(b) shows the relationship between the usage period of the tank 16 and the profile correction coefficient. The shorter the period of use, the smaller the correction coefficient for the head difference (pressure) of the profile.

Here, if the period of use is short, the viscosity of the liquid supplied from the tank 16 to the head 30 is low, and liquid ejection and meniscus rupture due to non-ejection driving are likely to occur. Therefore, in step S5, the control unit 20 multiplies the profile pressure by a correction coefficient of 1.1 to correct the profile pressure. As a result, the rate of change in pressure increases, so the control unit 20 generates a non-ejection drive waveform in which the vibration of the liquid is smaller than in the medium-term range where the usage period is longer than the short-term range. Thereby, the meniscus can be slightly vibrated to spread the liquid and reduce viscosity increase while suppressing ejection of the liquid and breakage of the meniscus.

The period of use becomes longer, the period of use becomes a medium period range, and then the period of use becomes a long period range, which is longer than the medium period range. As the period of use increases, the viscosity increases due to evaporation of the liquid. Therefore, the correction coefficient is 1 in the medium term range, 0.9 in the long term range, and becomes smaller as the usage period becomes longer.

In step S5, the control unit 20 corrects the profile pressure by multiplying the profile pressure by a correction coefficient of 1 or 0.9 depending on the period of use. This reduces the rate of change in pressure, so the control unit 20 generates a non-discharge drive waveform in which the vibration of the liquid increases as the period of use increases. As a result, in a state where liquid ejection and meniscus breakage are difficult to occur, the meniscus can be greatly vibrated to diffuse the liquid and reduce viscosity increase.

<Modification 4>
In the liquid ejection device 10 according to the fourth modification, the control unit 20 executes a correction process to correct the profile so that the lower the viscosity of the liquid, the larger the rate of change.

Specifically, the control unit 20 acquires the viscosity of the liquid supplied to the head 30. This viscosity is included in the print data, and the control unit 20 may obtain it from the print data. Further, the viscosity may be input to the control unit 20 by a user's operation of an operation unit or the like.

Between steps S2 and S3 of the flowchart shown in FIG. 8A, the control unit 20 corrects the profile so that the lower the viscosity of the liquid, the larger the rate of change, and executes the correction process (step S5 ). For example, FIG. 7(c) shows the relationship between liquid viscosity and profile correction coefficient. The higher the viscosity of the liquid, the smaller the correction coefficient for the head difference (pressure) of the profile.

If the viscosity of this liquid is low, ejection of the liquid due to non-ejection drive and breakage of the meniscus are likely to occur. Therefore, the control unit 20 corrects the profile pressure by multiplying the profile pressure by a correction coefficient of 1.1 for a low viscosity liquid whose viscosity is lower than a predetermined viscosity (medium viscosity). This increases the rate of change in pressure, so the control unit 20 generates a non-ejection drive waveform in which the vibration of the liquid is smaller than in the case of medium viscosity. Thereby, the meniscus can be slightly vibrated to spread the liquid and reduce viscosity increase while suppressing ejection of the liquid and breakage of the meniscus.

On the other hand, the control unit 20 corrects the profile pressure by multiplying the profile pressure by a correction coefficient of 0.9 for a high viscosity liquid that has a higher viscosity than a medium viscosity. This reduces the rate of change in pressure, so the control unit 20 generates a non-discharge drive waveform in which the vibration of the liquid is larger than in the case of medium viscosity. As a result, in a state where liquid ejection and meniscus breakage are difficult to occur, the meniscus can be greatly vibrated to diffuse the liquid and reduce viscosity increase.

Note that for medium-viscosity liquids, the control unit 20 multiplies the profile pressure by a correction coefficient of 1 to correct the profile pressure. Then, the control unit 20 generates a plurality of types of non-ejection drive waveforms in which the larger the rate of change in pressure in the profile, the smaller the vibration of the liquid.

<Modification 5>
In the liquid ejection device 10 according to the fifth modification, the control unit 20 executes a correction process to correct the profile such that the smaller the surface tension of the liquid, the larger the rate of change.

Specifically, the control unit 20 acquires the surface tension of the liquid supplied to the head 30. This surface tension is included in the print data, and the control unit 20 may obtain it from the print data. Further, the surface tension may be input to the control unit 20 by a user's operation of an operation unit or the like.

Between steps S2 and S3 of the flowchart shown in FIG. 8A, the control unit 20 corrects the profile so that the smaller the surface tension of the liquid, the larger the rate of change, and executes the correction process (step S5). For example, FIG. 7(d) shows the relationship between the surface tension of the liquid and the profile correction coefficient. The smaller the surface tension of the liquid, the larger the correction coefficient for the head difference (pressure) of the profile. Note that the influence of surface tension on liquid ejection and meniscus breakage due to non-ejection drive is smaller than viscosity, so the difference in the correction coefficient between a predetermined surface tension (medium tension) and a lower surface tension (low tension) is: It is smaller than the difference between the correction coefficients for medium and low viscosity.

If the surface tension of this liquid is small, liquid ejection due to non-ejection drive and meniscus breakage are likely to occur. Therefore, the control unit 20 corrects the profile pressure for a low tension liquid by multiplying the profile pressure by a correction coefficient of 1.01. This increases the rate of change in pressure, so the control unit 20 generates a non-discharge drive waveform in which the vibration of the liquid is smaller than in the case of medium tension. Thereby, the meniscus can be slightly vibrated to spread the liquid and reduce viscosity increase while suppressing ejection of the liquid and breakage of the meniscus.

On the other hand, the control unit 20 corrects the profile pressure by multiplying the profile pressure by a correction coefficient of 0.99 for a high tension liquid whose surface tension is higher than medium tension. As a result, the rate of change in pressure becomes smaller, so the control unit 20 generates a non-discharge drive waveform in which the vibration of the liquid is larger than in the case of medium tension. As a result, in a state where liquid ejection and meniscus breakage are difficult to occur, the meniscus can be greatly vibrated to diffuse the liquid and reduce viscosity increase.

Note that for medium tension liquids, the control unit 20 multiplies the profile pressure by a correction coefficient of 1 to correct the profile pressure. Then, the control unit 20 generates a plurality of types of non-ejection drive waveforms in which the larger the rate of change in pressure in the profile, the smaller the vibration of the liquid.

<Modification 6>
In the liquid ejection device 10 according to the sixth modification, the control unit 20 executes an ejection drive for ejecting liquid during constant speed movement, and performs adjustment processing to reduce the number of non-ejection drives as the ejection duty of the ejection drive increases. Execute.

Specifically, when the liquid is ejected from the nozzle 33 by the ejection drive, the control unit 20 stores the ejection history for each nozzle 33 in the RAM 24 at a predetermined timing. The ejection history is information regarding the amount of liquid ejected from the nozzle 33, and includes the amount of liquid ejected by ejection driving in the recording operation. This information is, for example, information about a recent predetermined number of times, information about a recent predetermined period of time, or information from tank 16 replacement. The ejection drive is performed every drive cycle of the recording operation.

The control unit 20 calculates the total amount of liquid ejected (total amount of ejected liquid) and the total number of drive cycles in the recording operation from the ejection history. The control unit 20 calculates the maximum total amount that can be ejected in a recording operation from a predetermined maximum amount that can be ejected at one time and the total number of drive cycles. The control unit 20 obtains the ratio of the total amount of ejection to the maximum total amount of ejection that can be ejected, and the ejection duty by the ejection drive. When the maximum amount of liquid that can be ejected is ejected from the nozzle 33 during the entire drive cycle of the recording operation, the ejection duty becomes 100%. If no liquid is ejected during the entire drive period of the recording operation, the ejection duty becomes 0%.

After step S4 of the flowchart shown in FIG. 8(b), the control unit 20 adjusts the number of times of non-ejection drive so that the greater the ejection duty of the ejection drive, the fewer the number of times of non-ejection drive, and executes adjustment processing (step S6). For example, FIG. 7(e) shows the relationship between the discharge duty and the drive rate of non-discharge drive during speed change.

If the ejection duty is less than 50%, the amount of liquid ejected is small, so there is a possibility that the liquid from the nozzle hole 33a is dry. For this reason, the control unit 20 generates a selection command so that the number of non-ejection drives during the speed change is 80% of the predetermined number, and outputs it to the head driver IC 40 together with a non-ejection waveform based on the profile. Based on the selection command and the non-ejection drive signal corresponding to the non-ejection waveform, the drive element 32 executes the non-ejection drive 80% of the predetermined number of times during the speed change. Thereby, the meniscus can be vibrated more and thickening of the liquid in the nozzle 33 can be reduced.

As the ejection duty increases, the number of non-ejection drives decreases. When the ejection duty is 50% or more and less than 80%, the number of times is 40% of the predetermined number, and when the ejection duty is 80% or more, the number of times is 8% of the predetermined number. In this way, the larger the ejection duty is, the larger the amount of liquid ejected from the nozzle 33 is, and the less the liquid in the nozzle 33 is dried. Therefore, the control unit 20 sets the number of non-discharge drives during the shift to 40% or 8% of the predetermined number, depending on the discharge duty. As a result, non-discharge drive is executed 40% or 8% of the predetermined number of times during the speed change. In this way, by reducing the number of non-ejection drives according to the ejection history, it is possible to reduce power consumption and suppress deterioration of the drive element 32.

<Modification 7>
In the liquid ejection device 10 according to Modification Example 7, the control unit 20 executes an adjustment process in which the higher the temperature of the liquid, the greater the number of non-ejection drives.

Specifically, as shown in FIG. 2, the liquid ejection device 10 includes a temperature sensor 39. The temperature sensor 39 is a sensor that detects the temperature of the liquid in the nozzle 33 in the head 30, and is provided in the head 30, for example.

After step S4 of the flowchart shown in FIG. 8(b), the control unit 20 adjusts the number of times of non-discharge drive so that the higher the temperature of the liquid detected by the temperature sensor 39, the greater the number of non-discharge drives, and performs adjustment processing. (Step S6). For example, FIG. 7(f) shows the relationship between the temperature of the liquid and the drive rate of non-discharge drive during speed change.

If the temperature of the liquid is in a high temperature range that is higher than a predetermined temperature range that includes room temperature, the liquid is likely to dry from the nozzle hole 33a. Therefore, the control unit 20 generates a selection command so that the number of non-ejection drives during the speed change becomes 50% of the predetermined number, and outputs it to the head driver IC 40. As a result, non-discharge drive is executed 50% of the predetermined number of times during the speed change. Thereby, the meniscus can be vibrated more and thickening of the liquid in the nozzle 33 can be reduced.

The lower the temperature of the liquid, the more difficult it is for the liquid to dry from the nozzle hole 33a. Therefore, if the temperature of the liquid is within the predetermined temperature range, the control unit 20 sets the number of non-discharge drives during the speed change to 40% of the predetermined number. If the temperature of the liquid is in the low temperature range lower than the predetermined temperature range, the control unit 20 sets the number of non-discharge drives during the speed change to 30% of the predetermined number. In this manner, by reducing the number of non-ejection drives as the temperature of the liquid is lower, it is possible to reduce power consumption and suppress deterioration of the drive element 32.

Note that all of the above embodiments may be combined with each other as long as they do not exclude each other. For example, modification example 2 is equivalent to modification example 1, modification example 3 is equivalent to modification examples 1 and 2, modification example 4 is equivalent to modification examples 1 to 3, modification example 5 is equivalent to modification examples 1 to 4, modification example 6 is equivalent to modification example 1 to 5 and Modification 7 may be applied to Modifications 1 to 6.

Additionally, from the above description, many modifications and other embodiments of the invention will be apparent to those skilled in the art. Accordingly, the above description is to be construed as illustrative only, and is provided for the purpose of teaching those skilled in the art the best mode of carrying out the invention. Substantial changes may be made in the structural and/or functional details thereof without departing from the spirit of the invention.

INDUSTRIAL APPLICATION The liquid ejection device of this invention, its control method, and its program are useful as a liquid ejection device, its control method, its program, etc. which can perform a non-ejection drive more reliably.

10: Liquid discharge device 15: Scanning mechanism 16: Tank 16a: Piping 20: Control unit 30: Head

Claims (11)

A tank for storing liquid,
a head that discharges the liquid;
piping that communicates the tank and the head and supplies the liquid to the head;
a scanning mechanism that moves the head in a scanning direction independently of the tank;
comprising a control unit;
The control unit includes:
a movement process in which the head is accelerated, moved at a constant speed, and then decelerated;
A plurality of types of non-discharge drive waveforms for vibrating the liquid so as not to discharge the liquid during at least one of the acceleration and deceleration are generated according to the pressure of the liquid in the head during the shift. waveform generation processing,
In a profile showing a relationship between the time during which the head moves and the pressure, a dividing process that divides the time during the shift into a plurality of time periods;
performing an acquisition process of acquiring a representative value of the pressure in the time period;
generating a waveform for the non-ejection drive according to the representative value in the waveform generation process;
Liquid discharge device. The liquid ejecting device according to claim 1 , wherein the larger the speed range that changes during the shift in the movement process, the larger the number of times the time is divided in the division process. The liquid ejection device according to claim 1 or 2 , wherein the control unit generates a waveform of the non-ejection drive in which the vibration of the liquid is smaller in the waveform generation process as the rate of change in the pressure with respect to the time is larger. . The liquid ejecting device according to claim 3 , wherein the control unit executes a correction process for correcting the profile so that the rate of change increases as the temperature of the liquid increases. the tank is replaceable;
comprising a counting section that counts the usage period of the tank,
5. The liquid ejecting device according to claim 3 , wherein the control unit executes a correction process for correcting the profile so that the rate of change becomes larger as the period of use of the tank becomes shorter. The liquid ejection device according to any one of claims 3 to 5 , wherein the control unit executes a correction process for correcting the profile such that the lower the viscosity of the liquid, the larger the rate of change. The liquid ejecting device according to claim 3 , wherein the control unit executes a correction process for correcting the profile such that the smaller the surface tension of the liquid, the larger the rate of change. A tank for storing liquid,
a head that discharges the liquid;
piping that communicates the tank and the head and supplies the liquid to the head;
a scanning mechanism that moves the head in a scanning direction independently of the tank;
comprising a control unit;
The control unit includes:
a movement process in which the head is accelerated, moved at a constant speed, and then decelerated;
A plurality of types of non-discharge drive waveforms for vibrating the liquid so as not to discharge the liquid during at least one of the acceleration and deceleration are generated according to the pressure of the liquid in the head during the shift. perform waveform generation processing, and
Executing a discharge drive to discharge the liquid during the constant speed movement,
executing an adjustment process that reduces the number of times of the non-ejection drive as the ejection duty of the ejection drive increases;
Liquid discharge device. A tank for storing liquid,
a head that discharges the liquid;
piping that communicates the tank and the head and supplies the liquid to the head;
a scanning mechanism that moves the head in a scanning direction independently of the tank;
comprising a control unit;
The control unit includes:
a movement process in which the head is accelerated, moved at a constant speed, and then decelerated;
A plurality of types of non-discharge drive waveforms for vibrating the liquid so as not to discharge the liquid during at least one of the acceleration and deceleration are generated according to the pressure of the liquid in the head during the shift. waveform generation processing,
performing an adjustment process of increasing the number of times the non-discharge drive is performed as the temperature of the liquid increases ;
Liquid discharge device. A tank for storing liquid,
a head that discharges the liquid;
piping that communicates the tank and the head and supplies the liquid to the head;
a scanning mechanism that moves the head in a scanning direction independently of the tank;
A control method for a liquid ejection device comprising a control unit,
The control unit includes:
a movement process in which the head is accelerated, moved at a constant speed, and then decelerated;
A plurality of types of non-discharge drive waveforms for vibrating the liquid so as not to discharge the liquid during at least one of the acceleration and deceleration are generated according to the pressure of the liquid in the head during the shift. perform waveform generation processing, and
Executing a discharge drive to discharge the liquid during the constant speed movement,
executing an adjustment process that reduces the number of times of the non-ejection drive as the ejection duty of the ejection drive increases;
A method of controlling a liquid ejection device. A tank for storing liquid,
a head that discharges the liquid;
piping that communicates the tank and the head and supplies the liquid to the head;
a scanning mechanism that moves the head in a scanning direction independently of the tank;
A liquid ejection device equipped with a control unit,
a movement process in which the head is accelerated, moved at a constant speed, and then decelerated;
A plurality of types of non-discharge drive waveforms for vibrating the liquid so as not to discharge the liquid during at least one of the acceleration and deceleration are generated according to the pressure of the liquid in the head during the shift. to perform waveform generation processing,
Executing a discharge drive to discharge the liquid during the constant speed movement,
executing an adjustment process that reduces the number of times of the non-discharge drive as the discharge duty of the discharge drive increases;
program.

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