Recording device, its driving method, and program

Abstract

This technology offers advantages in further improving the quality of recordings. [Solution] The recording device according to the present invention comprises a recording head that performs recording by ejecting ink, and a circulation mechanism that circulates ink in an ink circulation channel that passes through the recording head, further comprising a selection means for determining the ejection speed of ink droplets from the recording head, and a control means for controlling the drive of the circulation mechanism based on the selection result of the selection means.

Description

Technical Field

[0001] The present invention relates to a recording apparatus, a driving method thereof, and a program.

Background Art

[0002] Among recording apparatuses typified by inkjet printers and the like, there are those configured to circulate ink supplied to a recording head (see Patent Document 1). By circulating the ink, the quality of the ink is maintained, thereby making it possible to improve the quality of recording.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In general, a technique for appropriately performing ink circulation to further improve the quality of recording may be required.

[0005] An object of the present invention is to provide a technique advantageous for further improving the quality of recording.

Means for Solving the Problems

[0006] One aspect of the present invention relates to a recording apparatus, the recording apparatus comprising: a recording head that performs recording by discharging ink; a circulation mechanism that circulates ink in a circulation flow path of the ink passing through the recording head, specific means for specifying a discharge speed of ink droplets from the recording head; control means for performing drive control of the circulation mechanism based on a specification result of the specific means. It is characterized by the above. [Effects of the Invention]

[0007] According to the present invention, the quality of recordings can be improved. [Brief explanation of the drawing]

[0008] [Figure 1] A perspective view showing the external appearance of the recording device according to the embodiment. [Figure 2] A perspective view showing part of the internal structure of the recording device. [Figure 3] A schematic diagram showing the configuration of the recording head. [Figure 4] A schematic diagram showing the ink flow path of the recording head. [Figure 5A] A schematic diagram showing the configuration of the ink flow path in the recording head. [Figure 5B] A schematic diagram showing the structure of a pressure regulation mechanism. [Figure 5C] A schematic diagram showing how ink is circulated by a circulation pump. [Figure 6] A block diagram showing the control system for achieving ink circulation. [Figure 7A] A diagram showing the relationship between ink viscosity and ambient temperature. [Figure 7B] A diagram showing the relationship between ink viscosity and ink evaporation rate. [Figure 8] A diagram showing the relationship between ink viscosity and ink droplet ejection speed. [Figure 9] A schematic diagram illustrating a method for evaluating the ink ejection state. [Figure 10] A schematic diagram showing the configuration for determining the ink droplet ejection speed. [Figure 11A] A diagram showing the relationship between ink viscosity and circulation frequency. [Figure 11B] A diagram showing the relationship between ink viscosity and the drive voltage of the circulation actuator. [Figure 11C] A diagram showing the relationship between cyclic frequency and elapsed time. [Figure 12] A flowchart illustrating the method for controlling ink circulation. [Figure 13] A diagram showing the execution conditions for ink circulation control. [Figure 14] Block diagram showing a control system for realizing ink circulation. [Figure 15] Diagram showing a configuration example of a voltage generation circuit. [Figure 16] Diagram showing a configuration example of a voltage generation circuit. [Figure 17] Flowchart showing a method for controlling ink circulation. [Figure 18] Flowchart showing a method for controlling ink circulation.

Mode for Carrying Out the Invention

[0009] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the invention according to the claims. Although a plurality of features are described in the embodiments, not all of these plurality of features are essential to the invention, and the plurality of features may be arbitrarily combined. Further, in the accompanying drawings, the same or similar configurations are given the same reference numerals, and duplicate explanations are omitted.

[0010] ≪First Embodiment≫ <Regarding the Configuration of the Recording Device> FIG. 1 is a perspective view showing the appearance of a recording device 100. The recording device 100 is an inkjet printer configured to be able to perform recording on a recording medium 203 by ejecting ink from a recording head 201 described later (see FIG. 2). The recording device 100 includes a discharge guide 101, an operation panel 102, a display panel 103, an ink tank housing portion 104, and a temperature sensor 111. The discharge guide 101 guides and allows the recording medium 203, which has been recorded and discharged outside the device, to be loaded. The operation panel 102 allows the user to input setting information necessary for recording. The display panel 103 can display notification information to the user. The ink tank housing 104 can house ink tanks that store ink of multiple colors (in this embodiment, four colors: black (Bk), cyan (Cy), magenta (Ma), and yellow (Ye)) separately for each color. In addition, the temperature sensor 111 can detect the temperature under the recording environment (ambient temperature), and in this embodiment, it is positioned around the recording head 201, which will be described later.

[0011] Furthermore, the recording device 100 is further equipped with a cover 112 that can be opened and closed, allowing the user to open the cover 112 and access the inside of the device, enabling, for example, maintenance of the recording device 100 and installation of the recording medium 203.

[0012] In this context, "recording" refers to the process by which ink is ejected onto the recording medium 203 to form an image. The concept of an image includes characters, numbers, symbols, figures, photographs, etc., regardless of whether they are legible or not. Ink is typically a liquid containing dyes or pigments, but it may also be a colorless, transparent reaction liquid, and these can all be collectively referred to simply as a liquid. In this respect, the recording device 100 may be described as a liquid ejection device (similarly, the recording head 201 may be described as a liquid ejection head). Furthermore, the recording device 100 may be a copier that has recording as its primary function, and additionally includes auxiliary functions such as copying, scanning, and facsimile as secondary functions.

[0013] Figure 2 is a perspective view showing part of the internal structure of the recording device 100. The recording device 100 includes a recording head 201, a carriage 202, a guide rail 206, a conveyor belt 207, a carriage motor 208, a platen 212, and a conveyor roller 213. The carriage 202 is slidably supported along a guide rail 206 extending in the X direction and is capable of reciprocating in the X direction by receiving power from a carriage motor 208 via a conveyor belt 207. The recording head 201 is mounted on such carriage 202 and is capable of scanning in the X direction. The platen 212 supports the recording medium 203, which is conveyed in the Y direction by a conveyor roller 213, from below. With this configuration, the recording head 201 is capable of scanning the recording medium 203, which is conveyed in the Y direction, in the X direction to perform recording.

[0014] Recording to the recording medium 203 is achieved by alternating between an operation (intermittent transport) in which the transport roller 213 transports the recording medium 203 by a predetermined amount in the Y direction to suppress the transport, and an operation (recording scan) in which the recording head 201 scans in the X direction to perform recording. Such a recording head 201 is also referred to as a serial head. In another embodiment, the recording head 201 may be a line head capable of recording the entire width (X direction) of the recording medium 203 being transported in the Y direction at once.

[0015] The recording medium 203 can be any material (typically paper) that can form an image with ink ejected from the recording head 201. Here, a roll sheet is shown, but it may also be a cut sheet cut to a predetermined size. As an example of the ink used, latex ink is used. In this case, heating causes the water to evaporate, melting the latex resin and mixing with the pigment. A film is formed and hardens, thereby creating an image on the recording medium 203. Latex ink generally has a higher solvent ratio and ink viscosity compared to water-based ink.

[0016] Furthermore, the recording device 100 includes a linear scale 209 and an encoder sensor 210. The linear scale 209 extends along the guide rail 206, and the encoder sensor 210 can determine the position of the carriage 202 by detecting the linear scale 209.

[0017] Furthermore, the recording device 100 includes a distance detection sensor 204 and an ejection speed detection unit 205. The distance detection sensor 204 is installed on the recording head 201 and is capable of detecting the distance between the recording head 201 and the recording medium 203. The distance detection sensor 204 typically uses an optical sensor including a light-emitting element (not shown) that illuminates the recording medium 203 with light and a light-receiving element (not shown) that receives the light reflected from the recording medium 203, and is capable of measuring the distance based on their signal values. In addition, as will be described in detail later, the ejection speed detection unit 205 is capable of detecting the ejection speed of ink droplets ejected from the recording head 201.

[0018] <Regarding ink circulation> Figure 3 is a schematic diagram showing the configuration of the recording head 201. Figure 4 is a schematic diagram showing the ink flow path of the recording head 201 (arrows in the figure indicate the direction of ink flow). The recording head 201 includes an ejection unit 3 for ejecting ink and a circulation unit 302 for circulating the ink. Although not shown here, ink supply paths, connector insertion ports, etc., are formed to allow each color of ink to be supplied to the recording head 201. In this embodiment, the ejection unit 3 includes two element substrates 10, a flow path member 4, a support member 7, an electrical wiring member 5, and an electrical contact substrate 6.

[0019] The element substrate 10 consists of a semiconductor substrate such as a silicon substrate with multiple electrothermal conversion elements arranged on one side, and each electrothermal conversion element is capable of generating energy for ink ejection by passing an electric current through it. The electrothermal conversion elements may also be described as heat-generating resistance elements, heater elements, etc., but they may also be described as recording elements, liquid ejection elements, etc. On one side of the semiconductor substrate (the side on which the electrothermal conversion elements are arranged), a plate material is placed, with ink channels and pressure chambers formed to correspond to each individual electrothermal conversion element. The pressure chamber is connected to the ink channel and has a nozzle 304 that is provided to eject ink in the vicinity of the electrothermal conversion element. On the other side of the semiconductor substrate (the side opposite to the side on which the electrothermal conversion elements are arranged), there are individual supply channels 19 through which ink flows into and is supplied to each individual ink channel, and individual recovery channels 18 through which ink flows out from each individual ink channel and is recovered.

[0020] The flow channel member 4 has a supply channel 20 and a recovery channel 21, which are connected to individual supply channels 19 and individual recovery channels 18, respectively, above the element substrate 10. The support member 7 has an opening at a position corresponding to the element substrate 10, is fixedly positioned relative to the flow channel member 4, and supports the electrical wiring member 5 so that it can be electrically connected to the element substrate 10. The electrical wiring member 5 is capable of supplying drive signals to the element substrate 10 for driving the electrothermal conversion element.

[0021] In Figure 4, multiple nozzles 304 are arranged in the depth direction (Y direction) to form a nozzle row, and multiple individual supply channels 19 and individual recovery channels 18 are similarly arranged along this nozzle row. The individual supply channels 19 are connected to a supply channel 20 formed at a certain position on the flow channel member 4 and are connected to the corresponding colored circulation unit 302 via a joint member 8 having a supply port. Similarly, the individual recovery channels 18 are connected to a recovery channel 21 formed at another position on the flow channel member 4 and are connected to the corresponding colored circulation unit 302 via a joint member 8 having a recovery port.

[0022] With this configuration, ink of each color is supplied from the circulation unit 302 to the nozzle 304, sequentially through the supply port of the joint 8, the supply channel 20, and the individual supply channel 19. The ink supplied to the nozzle 304 is then recovered back into the circulation unit 302, sequentially through the individual recovery channel 18, the recovery channel 21, and the recovery port of the joint 8. In this way, ink circulation is achieved.

[0023] Figure 5A is a schematic diagram showing the configuration of the ink flow path for one color in the recording head 201 from another side (arrows in the figure indicate the direction of ink flow). The recording head 201 includes a filter 110, a first pressure adjustment mechanism 120, a supply flow path 130, a recovery flow path 140, a second pressure adjustment mechanism 150, a bypass flow path 160, and a circulation pump 500.

[0024] Ink supplied from the ink tank in the ink tank housing 104 is pumped under pressure by a pressure pump (not shown), passes through the filter 110, and is supplied under reduced pressure to the liquid chamber (first liquid chamber) in the pressure adjustment mechanism 120. The reduced-pressure ink is supplied to the element substrate 10 through the supply channel 130 and to the pressure chamber where the nozzle 304 is provided. When the aforementioned electrothermal conversion element is driven, a portion of the ink in the pressure chamber is discharged from the nozzle 304, and another portion (all of it if the electrothermal conversion element is not driven) is supplied to the liquid chamber (second liquid chamber) in the pressure adjustment mechanism 150 through the recovery channel 140. The circulation pump 500 pumps the ink from the liquid chamber of the pressure adjustment mechanism 150 back to the liquid chamber of the pressure adjustment mechanism 120. In this way, an ink circulation path is formed. Furthermore, the supply channel 130 corresponds to the supply channel 20 and the supply port of the joint member 8, and the recovery channel 140 corresponds to the recovery channel 21 and the recovery port of the joint member 8.

[0025] Figure 5B(a) is a schematic diagram showing the structure of the pressure regulating mechanism 150. The pressure regulating mechanism 150 comprises a valve chamber 151, a pressure control chamber 152, and a communication port 191 connecting them. The valve chamber 151 is provided with a valve 190 that can open and close the communication port 191. The valve 190 is made of an elastic material at least in part and is biased by a valve spring 200 in the direction of closing the communication port 191. A pressure plate 215 and a flexible member 230 are arranged on the outer surface of the pressure control chamber 152, and the pressure plate 215 is displaceable by the flexible member 230. This configuration can be manufactured by heat welding the pressure plate 215, which is made of a resin molded part, to the flexible member 230, which is made of a resin film.

[0026] The pressure plate 215 and the flexible member 230 are biased outward by the pressure adjustment spring 220 (in the direction that expands the volume of the pressure control chamber 152). When the negative pressure inside the pressure control chamber 152 increases, the pressure plate 215 is displaced in a direction that decreases the volume of the pressure control chamber 152, and when the pressure inside the pressure control chamber 152 reaches a predetermined negative pressure, the pressure plate 215 comes into contact with the tip of the valve 190. When the negative pressure increases further, as shown in Figure 5B(b), the pressure plate 215 pushes the valve 190 inward, opening the communication port 191. The pressure in the valve chamber 151 is controlled to be higher than the pressure in the pressure control chamber 152, so that when the communication port 191 is open, ink flows from the valve chamber 151 into the pressure control chamber 152. Consequently, as shown in Figure 5B(c), the pressure plate 215 is displaced in a direction that expands the volume of the pressure control chamber 152, and the communication port 191 closes. In this way, when the negative pressure exceeds a certain level, ink flows in from the valve chamber 151 through the communication port 191, preventing the negative pressure from exceeding that level, and thus the pressure inside the pressure control chamber 152 can be controlled within a predetermined range.

[0027] The elements and their functions of the pressure adjustment mechanism 150, as explained with reference to Figures 5B(a) to (c), are the same for the pressure adjustment mechanism 120.

[0028] The circulation pump 500 is equipped with a piezoelectric element (piezoelectric element 303 in Figure 6, described later) and a diaphragm. By applying voltage to the piezoelectric element, the electrostrictive effect generated makes it possible to vibrate the diaphragm. This circulates the ink in the recording head 201, maintaining the freshness of the ink near the nozzle 304 and preventing, for example, ink viscosity increase.

[0029] Figure 5C is a schematic diagram showing the circulation of ink by the circulation pump 500. In the figure, the valve chamber 121 to the pressure control chamber 122 of the pressure adjustment mechanism 120 corresponds to the valve chamber 151 to the pressure control chamber 152 of the pressure adjustment mechanism 150. The ink in the pressure control chamber 122 is supplied to the supply channel 130 and the bypass channel 160. The ink supplied to the supply channel 130 is supplied to the element substrate 10 and ejected from the nozzle 304, or, if not ejected from the nozzle 304, returns to the pressure control chamber 152 via the recovery channel 140. Meanwhile, the ink supplied to the bypass channel 160 is supplied to the pressure control chamber 152 through the valve chamber 151. The ink supplied to the pressure control chamber 152 is supplied to the circulation pump 500 through the pump inlet channel 170, and then supplied to the pressure control chamber 122 through the pump outlet channel 180. The pressure in the pressure control chamber 122 is controlled to be higher than the pressure in the pressure control chamber 152, thereby supplying the ink in the pressure control chamber 122 to the supply channel 130.

[0030] The aforementioned flow channels for achieving this ink circulation can be collectively referred to as circulation channels, and the aforementioned mechanism for achieving this ink circulation can be collectively referred to as a circulation mechanism.

[0031] Figure 6 is a block diagram showing the control system for realizing the ink circulation described above. The recording device 100 further comprises a control board 401. The control board 401 comprises a CPU 402, converters 403 and 404, a voltage switching circuit 405, and a ROM 406. DC-DC converters may be used for converters 403 and 404, respectively.

[0032] In the recording head 201, the piezoelectric element 303 is connected to the control board 401 via electrical connection terminals 409, and outputs A and B from converters 403 and 404, respectively, are input to the piezoelectric element 303 by switching via the voltage switching circuit 405. The CPU 402 controls the resistance values ​​in the circuits forming converters 403 and 404, and also controls the switching elements such as MOS transistors in the voltage switching circuit 405. This allows for adjustment of the voltage value, frequency, phase, pulse width, rise edge and fall edge times (duration, timing, etc.) input to the piezoelectric element 303. Details of the switching by the voltage switching circuit 405 will be described later. ROM 406 functions as a memory unit that stores information related to the execution of recording, such as ambient temperature and ink circulation time, and CPU 402 can control the piezoelectric element 303 based on this information. Non-volatile memory such as flash memory may be used for ROM 406.

[0033] <Regarding ink viscosity> Figure 7A shows the relationship between the viscosity of the ink ejected from nozzle 304 (ink viscosity around nozzle 304) and the ambient temperature (temperature around nozzle 304). As can be seen from this figure, the ink viscosity increases as the ambient temperature decreases. Figure 7B shows the relationship between ink viscosity and ink evaporation rate. When the ambient temperature rises, water evaporates more easily from the nozzle 304, increasing the ink evaporation rate. As water evaporates from the nozzle 304, the ink viscosity increases. Furthermore, if the time during which ink circulation is suppressed (non-circulation time) is extended, the ink viscosity increases due to the sedimentation of ink components. In other words, ink viscosity changes due to various factors, and therefore it is difficult to estimate based on a single factor.

[0034] Figure 8 shows the relationship between the ink viscosity and the velocity (discharge rate) of ink droplets ejected from the nozzle 304. When the ink discharge conditions are the same except for the ink viscosity (for example, when the same energy is applied to the ink by driving the electrothermal conversion element and the ink is discharged from the same nozzle 304), the ink discharge rate decreases as the ink viscosity increases. Furthermore, as can be seen from Figure 8, there is a correlation between ink viscosity and ink droplet ejection speed; that is, the ink viscosity around nozzle 304 can be determined based on the ink droplet ejection speed.

[0035] <Identifying the ink ejection speed> Figure 9 is a schematic diagram illustrating the method for evaluating the ink ejection state by the ejection speed detection unit 205, showing a view in the X direction of an ejection port row 708, which is made up of multiple nozzles 304 arranged in a row. In this embodiment, the ejection speed detection unit 205 includes a light-emitting element 702, a light-receiving element 703, an aperture for the light-emitting element 704, an aperture for the light-receiving element 705, and an ink absorber 706. The ink absorber 706 is configured to absorb ink droplets 707 ejected from the nozzles 304, and a porous material such as a sponge may be used.

[0036] The light-emitting element 702 and the light-receiving element 703 are arranged such that the ink droplet 707 ejected from the nozzle 304 blocks the light beam 709. For example, an infrared LED with a relatively narrow directivity is used for the light-emitting element 702. When detecting the ejection speed of the ink droplet 707, a voltage (e.g., 5V) is applied to the light-emitting element 702. The light beam 709 from the light-emitting element 702 is incident on the light-receiving element 703 and detected. For example, a photodiode with high sensitivity in the infrared region is used for the light-receiving element 703.

[0037] The recording head 201 is scanned up to the ejection speed detection unit 205 when detecting the ejection speed, and then each nozzle 304 is driven in sequence. The ink droplets 707 ejected from the nozzles 304 block the light beam 709 (passing through the light beam 709) and land on the ink absorber 706 where they are absorbed.

[0038] Here, let L be the distance from nozzle 304 to light beam 709. Also, let T be the time difference between the drive signal of nozzle 304 when ejecting ink droplet 707 and the detection signal of light-receiving element 703 when ink droplet 707 blocks the light beam 709 (for example, the time difference between the rise edge of the drive signal and the rise edge of the detection signal). In this case, the ejection speed V of ink droplet 707 is, V = L / T This is the result.

[0039] In the example shown in Figure 9, the ejection speed of the ink droplet 707 is calculated using an optical sensor (light-emitting element 702 and light-receiving element 703) that detects when the ink droplet 707 obstructs the light beam 709, but other methods may be employed. For example, the ejection speed may be calculated using an electrostatic sensor that detects the voltage change that may occur due to the impact of the ink droplet 707. If the ejection speed detection unit 205 or other detection means are not used, the ejection speed may be calculated, for example, by recording a predetermined pattern and measuring the amount of positional displacement.

[0040] Figure 10 is a schematic diagram showing other configurations for determining the ejection speed of ink droplets 707. The distance between the recording head 201 and the recording medium 203 is denoted as distance H, which is detected by the distance detection sensor 204. The scanning speed (movement speed) of the recording head 201 in the X direction is denoted as speed Vcr, and the ejection speed of ink droplets 707 is denoted as speed V. As an example, the landing position of the ink droplet 707 is adjusted by recording a predetermined pattern (position adjustment pattern) on the recording medium 203. For example, the timing of ejection of ink droplets 707 ejected in the forward direction (e.g., +X direction) and ink droplets 707 ejected in the return direction (e.g., -X direction) is adjusted. At this time, the distance X of the positional shift from the time the ink droplet 707 is ejected in the forward direction to the time the ink droplet 707 lands on the recording medium 203 is: X = (H / V) * Vcr It is expressed as follows. Therefore, the ejection speed V of the ink droplet 707 is, V = (H / X) * Vcr This is how it is calculated. In this way, the discharge speed V can be calculated based on the distance H detected by the distance detection sensor 204 and the distance X determined by the position adjustment pattern.

[0041] In the above example, the ejection speed V of the ink droplet 707 was indirectly determined by calculation, but the ejection speed V may also be determined directly by measurement.

[0042] <About the characteristics of ink viscosity> Figure 11A shows the relationship between the ink viscosity and the ink circulation frequency (hereinafter referred to as the circulation frequency). The circulation frequency corresponds to the drive frequency of the circulation pump 500 (i.e., the driving force for circulating the ink), and in this embodiment, it corresponds to the drive frequency of the piezoelectric element 303 (i.e., the number of vibrations of the diaphragm per unit time). The circulation frequency may also be expressed as the stirring frequency, as it is the frequency for stirring the ink. When the circulation frequency is high, the amount of ink circulated increases and the ink is stirred more, so the thickening of the ink around the nozzle 304 is suppressed. As described here with reference to Figures 7A, 7B, and 8, when the ink viscosity changes, the ejection speed of the ink droplets 707 also changes. And, as can be seen from Figure 11A, the ink viscosity around the nozzle 304, i.e., the ejection speed of the ink droplets 707, can be controlled and maintained at a constant level by the circulation frequency mentioned above.

[0043] Figure 11B shows the relationship between the ink viscosity and the driving voltage (voltage value input to the piezoelectric element 303) of the circulating actuator formed by the piezoelectric element 303 and the diaphragm. When the driving voltage increases and the vibration energy of the piezoelectric element 303 increases, the ink is further agitated, which suppresses the rate of increase in ink viscosity and lowers the ink viscosity around the nozzle 304. In other words, the ink viscosity around the nozzle 304, i.e., the ejection speed of the ink droplets 707, can be controlled and maintained at a constant level by adjusting the driving voltage of the circulating actuator.

[0044] <About the circulating actuator> Figure 15 shows an example configuration of a voltage generation circuit 159 that makes the drive voltage of the circulating actuator (the voltage value input to the piezoelectric element 303) variable, and the voltage generation circuit 159 corresponds to the converters 403 and 404 in Figure 6, respectively. The voltage generation circuit 159 includes a resistor R0, a resistor R1, a potentiometer (variable resistor) RX, a MOS transistor M1, an inductor L1, a capacitor C1, a Schottky barrier diode D1, and a control circuit unit 1201.

[0045] The control circuit 1201 feeds back the voltage division of the output voltage Vout by the resistors R0 and R1 and the potentiometer RX as a reference voltage to the MOS transistor M1, and controls the gate of the MOS transistor M1. By making the resistance value of the potentiometer RX variable, it is possible to set the output voltage Vout to a value corresponding to the resistance ratio of the resistors R0 and R1 and the potentiometer RX. For example, if the ejection speed of the ink droplet 707 falls outside the standard range, the resistance value of the potentiometer RX should be changed. That is, by decreasing the resistance value of the potentiometer RX, the output voltage Vout can be increased, and by increasing the resistance value of the potentiometer RX, the output voltage Vout can be decreased. This makes it possible to adjust the ink viscosity to the desired level and bring the ejection speed of the ink droplet 707 within the standard range. Furthermore, the resistance value of potentiometer RX may be changed by an electrical signal, or it may be changed manually.

[0046] Figure 16 shows another example of the configuration of the voltage generation circuit 159' for varying the drive voltage of the circulating actuator, similar to Figure 15. The voltage generation circuit 159' includes resistors R11 to R15 and switch elements SW1 to SW5, replacing the resistor element R1 and potentiometer RX described above. The resistors R11 to R15 have different resistance values, and in this example, the resistance values ​​increase in this order (when these resistance values ​​are expressed as R11 to R15, R11 <R12<R13<R14<R15とする。)。

[0047] Switch elements SW1 to SW5 are directly connected to resistor elements R11 to R15, respectively, and are controlled by control signals CON1 to CON5 from CPU 402. Here, it is assumed that control signals CON1 to CON5 control one of the switch elements SW1 to SW5 to the conducting state (ON state), and the other switch elements to the non-conducting state (OFF state). As an example, when switch element SW1 is in a conducting state (other switch elements (SW2~SW5) are in a non-conducting state), the voltage division of the output voltage Vout by resistor elements R0 and R11 is fed back to MOS transistor M1 as a reference voltage. As another example, when switch element SW2 is in a conducting state (other switch elements (SW1, SW3~SW5) are in a non-conducting state), the voltage division of the output voltage Vout by resistor elements R0 and R12 is fed back to MOS transistor M1 as a reference voltage.

[0048] With this configuration, the output voltage Vout can be changed depending on which of the switch elements SW1 to SW5 is in a conductive state. Therefore, the adjustment of the ink viscosity and the corresponding adjustment of the ink droplet ejection speed 707 can be achieved by electrical signals.

[0049] Here, outputs A and B from converters 403 and 404, respectively (see Figure 6), may be positive and negative values, respectively. By doing so, it becomes possible to increase the voltage value input to the piezoelectric element 303 (the difference between the voltage value input to one end of the piezoelectric element 303 and the voltage value input to the other end).

[0050] Any known configuration can be used for the voltage switching circuit 405; for example, an H-bridge circuit can be used. In this case, by changing the amount of current supplied to the gates of the source and sink FET components (transistors) of the H-bridge circuit, it is possible to control the rise edge and fall edge times of the voltage waveform input to the piezoelectric element 303. For example, by increasing the amount of current supplied to the gates of the FET components, the rise edge and fall edge times can be made faster, and by decreasing the amount of current, the rise edge and fall edge times can be made slower. In this way, when the ejection speed of the ink droplets 707 falls outside the reference range, the rise edge and fall edge times can be controlled, thereby adjusting the ink viscosity to the desired level and bringing the ejection speed of the ink droplets 707 within the reference range.

[0051] <Regarding ink circulation control> Figure 12 is a flowchart showing the method for controlling ink circulation according to this embodiment. The flowchart outlines how to stabilize the ejection speed of ink droplets 707 by changing the circulation frequency so that the ejection speed of ink droplets 707 is within a reference range, and each step to achieve this can be executed by the control board 401 (mainly the CPU 402).

[0052] In response to the recording device 100 receiving a print job in step S1001 (hereinafter simply referred to as "S1001"; the same applies to other steps described later), the ejection speed of the ink droplets 707 is calculated in step S1002. In this embodiment, this calculation is performed using the ejection speed detection unit 205 (see Figure 9). The print job may include a command instructing the execution of recording, image data to be recorded, setting information necessary for the execution of recording, etc.

[0053] In S1003, it is determined whether the ejection speed of the ink droplets 707 calculated in S1002 is within the standard range. If the ejection speed is within the standard range, the process proceeds to S1019; otherwise, it proceeds to S1004. In S1019, assuming that ink circulation control is being performed appropriately, recording based on the print job in S1001 begins.

[0054] In S1004, it is determined whether the ejection speed of the ink droplet 707 is higher (faster) than the upper limit of the above reference range, or lower (slower) than the lower limit of the above reference range. If the ejection speed is higher than the upper limit, the process proceeds to S1005; if the ejection speed is lower than the lower limit, the process proceeds to S1007.

[0055] In S1005, the energy used for ink circulation is deemed excessive, and the circulation frequency is changed to a lower frequency (0.9 times in this embodiment). In S1020, the ejection speed of the ink droplets 707 is calculated. Subsequently, in S1006, following the same procedure as in S1003, it is determined whether the ejection speed of the ink droplets 707 is within the standard range. If the ejection speed is within the standard range, the process proceeds to S1019; otherwise, it proceeds to S1017. In S1017, the number of times the circulation frequency has been changed to a lower frequency (S1005) is determined. If the number of changes is greater than or equal to a predetermined number (4 times in this embodiment), the process proceeds to S1018; otherwise, it returns to S1005. In S1018, if the ejection speed does not fall within the standard range due to the change to a lower circulation frequency, an error message is displayed on the display panel 103, for example, and the user is notified that maintenance of the recording device 100 is required. In this way, if the ejection speed of the ink droplet 707 is higher than the upper limit of the reference range, the ejection speed is brought within the reference range by changing the circulation frequency to a lower value a predetermined number of times, and recording begins. If the ejection speed does not fall within the reference range after changing the circulation frequency a predetermined number of times, an error message is displayed.

[0056] In S1007, assuming that there is insufficient energy used for ink circulation, the circulation frequency is changed to a higher frequency (1.1 times in this embodiment), and in S1008, the ejection speed of the ink droplet 707 is calculated. Then, in S1009, following the same procedure as in S1003, it is determined whether or not the ejection speed of the ink droplet 707 is within the reference range. If the ejection speed is within the reference range, the process proceeds to S1019; otherwise, it proceeds to S1010. In S1010, assuming that the energy used for ink circulation is still insufficient, the circulation frequency is changed to a higher frequency (1.1 times higher in this embodiment), and in S1011, the ejection speed of the ink droplets 707 is calculated. Then, in S1012, following the same procedure as in S1003, it is determined whether the ejection speed of the ink droplets 707 is within the reference range. If the ejection speed is within the reference range, the process proceeds to S1019; otherwise, it proceeds to S1013. In S1013, the circulation frequency is changed to an even higher one (1.2 times higher in this embodiment), and in S1014, the ejection speed of the ink droplet 707 is calculated. Then, in S1015, it is determined whether the ejection speed of the ink droplet 707 is within the reference range using the same procedure as in S1003. If the ejection speed is within the reference range, the process proceeds to S1019; otherwise, it proceeds to S1016.

[0057] If the process proceeds to S1016, it is likely that the ejection speed falls outside the standard range due to aging of the recording head 201 itself (not due to insufficient energy for ink circulation). Therefore, in S1016, ejection timing adjustment is performed to adjust the timing of ejection of ink droplets 707, and then the process proceeds to S1019 (start of recording based on the print job). The ejection timing adjustment can be performed using a known method, and typically, it can be performed based on the amount of positional deviation of the recorded pattern for each color in both the forward and return directions. If the ejection speed of ink droplets 707 falls below the allowable value (a value even lower than the lower limit), an error display may be output, similar to S1018.

[0058] Changing to a lower / higher circulating frequency can be achieved by changing the voltage (outputs A and B) input to the piezoelectric element 303 (see Figure 6). The configuration of the voltage switching circuit 405 can be realized by a known circuit configuration using a selector, etc., but it may be modified within the scope that does not deviate from its purpose.

[0059] According to the ink circulation control described above, for each color, it is determined whether the ejection speed of the ink droplet 707 is within the standard range. If the ejection speed is not within the standard range, the circulation frequency is adjusted or controlled so that the ejection speed is within the standard range. Therefore, according to this embodiment, the ejection speed of the ink droplet 707 is stabilized to be within the standard range, and the quality of the recording can be improved. This is also true when different types of ink are used (for example, when the ink composition is changed).

[0060] In this embodiment, the circulating frequency is increased or decreased by a predetermined multiplier (0.9x, 1.1x, and 1.2x in this embodiment), but the multiplier may be any other value, or it may be changed to a fixed value instead of being increased or decreased based on a multiplier. Furthermore, when the circulation pump 500 is driven by PWM (Pulse Width Modulation) control, the duty cycle of the drive signal for the circulation pump 500 may be changed instead of / in addition to changing the circulation frequency. That is, the means for controlling the driving force for circulating the ink, or the means for keeping the ejection speed of the ink droplets 707 within a reference range, may be changed based on the configuration of the circulation mechanism, without departing from its purpose.

[0061] The above-described adjustment of the circulation frequency is performed so that the ejection speed of ink droplets 707 for one color falls within a reference range, and the adjusted circulation frequency may then be applied to other colors as well. If the ink composition differs between colors, the circulation frequency may be adjusted for each color (individually). The same applies to increasing or decreasing the magnification (0.9x, 1.1x, 1.2x in this embodiment), and the amount of increase or decrease may be set to different values ​​for each color.

[0062] Other modifications to the flowchart described herein may be made to achieve similar effects. For example, in S1005, S1007, S1010, and S1013, the voltage input to the piezoelectric element 303 may be adjusted by controlling the switch elements SW1 to SW5 illustrated in Figure 16. For example, in the initial state, switch element SW2 is set to conduct. At this time, in S1005, switch element SW1 is set to conduct; in S1007, switch element SW3 is set to conduct; in S1010, switch element SW4 is set to conduct; and in S1013, switch element SW5 is set to conduct.

[0063] As another example, the rise edge and fall edge times of the voltage waveform input to the piezoelectric element 303 may be controlled. This can be achieved, for example, by changing the amount of current supplied to the gate of the FET component in the aforementioned H-bridge circuit that can be used in the voltage switching circuit 405. For example, the amount of current supplied to the gate of the FET component may be reduced by 20% from the initial state in S1005, increased by 10% from the initial state in S1007, increased by 10% from the state in S1010 in S1010, and increased by 10% from the state in S1010 in S1013.

[0064] Furthermore, some of the above modifications may be combined, and the voltage value input to the piezoelectric element 303 and the rise edge and fall edge times of its waveform may be used in combination.

[0065] ≪Second Embodiment≫ In the first embodiment described above, an example was shown in which the ejection speed of the ink droplets 707 is detected and the circulation frequency is adjusted during recording. However, the circulation frequency may be adjusted at other times. The circulation frequency may be adjusted, for example, based on the timing result of an internal timer (not shown) when the recording device 100 is in standby mode (a state in which a print job is being accepted) or sleep mode (a power-saving state), or it may be adjusted based on the fulfillment of various conditions.

[0066] Figure 13 shows the conditions for performing circulation frequency adjustment, specifically the factors related to ink viscosity and the corresponding timing conditions for performing circulation frequency adjustment. Ink viscosity fluctuates depending on factors such as ambient temperature, non-circulation time, and the degree of equipment degradation (mainly the degree of degradation of the piezoelectric element 303). Therefore, it is desirable to establish timing conditions for when circulation frequency adjustment should be performed for each individual factor related to ink viscosity. For example, regarding ambient temperature, the execution condition may be set if the ambient temperature has changed above a certain threshold since the last time the circulation frequency was adjusted, for example, if there has been a temperature change of 10°C or more. Regarding non-circulation time, the execution condition may be set if the recording device 100 is started / powered on and the elapsed time thereafter meets a certain threshold. Regarding device degradation, the execution condition may be set if the cumulative recording time meets a certain threshold, for example, if 100 hours of recording have been performed since the last circulation frequency adjustment. The above-mentioned non-circulation time, elapsed time, and cumulative time can be measured by an internal timer.

[0067] If any of the above conditions are met, the circulating frequency is adjusted using the same procedure as in Figure 12, and in this case, the circulating frequency may be increased or decreased by a different multiplier than that of the first embodiment described above. For example, the circulating frequency may be changed by 1.2 times in S1010 and by 1.5 times in S1013.

[0068] For example, by storing the ambient temperature at the time of the previous circulating frequency adjustment (the previous ambient temperature) in the ROM 406, the circulating frequency can be adjusted if the ambient temperature detected by the temperature sensor 111 has changed by 10°C or more from the previous ambient temperature.

[0069] As another example, regarding non-cyclic time, while the recording device 100 is running, the cyclic frequency may be adjusted periodically in accordance with whether the elapsed time meets a criterion. However, if the recording device 100 is stopped / powered off, the cyclic frequency is not adjusted, so it would be desirable to adjust the cyclic frequency when the recording device 100 is started again.

[0070] As another example, if the piezoelectric element 303 is degraded, it is possible that insufficient energy necessary for ink circulation cannot be obtained. In such cases, as shown in Figure 14, a counter 1301 for measuring the cumulative operating time of the piezoelectric element 303 is provided on the control board 401, and the circulation frequency is adjusted according to whether the cumulative operating time meets a standard. This can be achieved by storing the measurement results of the counter 1301 in the ROM 406. Furthermore, if multiple piezoelectric elements 303 are used, the cumulative operating time of each piezoelectric element 303 is measured, and the circulation frequency is adjusted according to whether any of the measurement results meet a standard.

[0071] According to this embodiment, the circulating frequency is adjusted in response to the fulfillment of any of several conditions, and for each color, it is possible to stabilize the ejection speed of the ink droplets 707 within a reference range, thereby further improving the quality of recording. Similar to the first embodiment described above, the adjustment of the circulating frequency in this embodiment is performed for one color, and the adjusted circulating frequency can then be applied to other colors, although the adjustment of the circulating frequency may be performed for each color (individually).

[0072] ≪Third Embodiment≫ Figure 11C shows the relationship between the circulation frequency, which is set so that the ejection speed of the ink droplets 707 is within a reference range, and the elapsed time when the piezoelectric element 303 is continuously driven. An increase in elapsed time corresponds to the progression of deterioration of the piezoelectric element 303 over time. As the elapsed time increases, the displacement of the piezoelectric element 303 decreases, reducing the ink stirring efficiency, and thus increasing the ink viscosity around the nozzle 304. Therefore, the circulation frequency is feedback-controlled to approach the target value shown by the dashed line, and reaches the set upper limit as time progresses. In the third embodiment, ink circulation control is performed taking this into consideration.

[0073] Figure 17 is a flowchart showing the ink circulation control method according to this embodiment. Note that the same steps as those described with reference to Figure 12 (S1001-S1009 and S1016-S1020) will not be explained.

[0074] In S1701 (if it is determined in S1003 that the ejection speed of the ink droplets 707 is within the standard range), the current / currently set circulation frequency (or its set value) is stored in ROM 406. Subsequently, in S1702, it is determined whether a predetermined period has elapsed since the recording device 100 began to be used. If the predetermined period has elapsed, the process proceeds to S1703; otherwise, it proceeds to S1019. In S1703, the history of the circulating frequency up to that point (history stored in ROM406) is referenced, and the time until the circulating frequency reaches the set upper limit is calculated, for example, based on an approximation curve calculated using a known calculation formula, and the result is notified to the user. The set upper limit here refers to the upper limit that can be set for the circulating frequency, and it is sufficient if it has been identified and set in advance through evaluation tests or the like.

[0075] In S1711 (if the discharge speed is determined to be within the standard range in S1009), it is determined whether the circulation frequency has reached the set upper limit. If the circulation frequency has reached the set upper limit, the process proceeds to S1016; otherwise, it returns to S1007. Furthermore, after the discharge timing adjustment is performed in S1016 and before recording starts in S1019, S1712 provides the user with a notification recommending maintenance. This maintenance typically involves replacing components of the recording device 100 (such as the recording head 201 and circulation mechanism), but may also involve repairing parts by the user or a service technician.

[0076] According to this embodiment, if a predetermined period of time has elapsed since the recording device 100 began to be used, the user is notified of the time remaining until the circulating frequency reaches the set upper limit. Furthermore, when the circulating frequency reaches the set upper limit, the user is notified of a recommendation for maintenance before the production efficiency of recording decreases due to the adjustment of the discharge timing. Therefore, according to this embodiment, the same effects as the first embodiment described above can be obtained, and in addition, it becomes possible for the user to plan the operation of the recording device 100, such as preparing replacement parts (e.g., the recording head 201).

[0077] Figure 18 is a flowchart illustrating an example of a variation of this embodiment, in which further steps are performed based on whether or not the change in the setting of the circulating frequency is within an acceptable range. After the circulating frequency being set in S1701 is stored in ROM 406, and before it is determined in S1702 whether a predetermined period has elapsed, S1801 determines whether the set value of the circulating frequency deviates from the previous set value by more than a standard. If the set value of the circulating frequency deviates from the standard, the process proceeds to S1018; otherwise, it proceeds to S1702. Here, a deviation of more than a standard means that the difference between the current set value and the previous set value is outside the acceptable range.

[0078] Similarly, after it is determined in S1711 that the circulation frequency has reached the set upper limit, and before the discharge timing adjustment is performed in S1016, S1811 determines whether the set value of the circulation frequency deviates from the previous set value by more than a standard. If the set value of the circulation frequency deviates by more than a standard, the process proceeds to S1018; otherwise, it proceeds to S1812. Subsequently, in S1812, the calculated value of the ejection speed of the ink droplet 707 is stored in ROM406.

[0079] Then, in S1813, it is determined whether the calculated value of the discharge speed is below the lower limit. If the calculated value of the discharge speed is below the lower limit, the process proceeds to S1018; otherwise, it proceeds to S1814. In S1814, the history of previous discharge speed calculations (history stored in ROM406) is referenced, and for example, based on an approximation curve calculated using a known calculation formula, the time until the discharge speed reaches the lower limit is calculated, and the result is notified to the user.

[0080] According to this modified version, an error message is displayed if the change in the circulating frequency setting is outside the acceptable range, while the user is notified of the time until maintenance even if the change is within the acceptable range. This allows the user to prepare replacement parts (e.g., recording head 201) in advance in preparation for maintenance, enabling more planned operation of the recording device 100 by the user.

[0081] In the first to third embodiments, adjusting the circulation frequency was exemplified as one means of bringing the ejection speed of the ink droplets 707 within a reference range. However, it is sufficient that the driving force for circulating the ink is controlled, and this can be achieved by other means. That is, the ink circulation flow rate may be controlled, and as an example, the opening degree of a predetermined valve that can be placed at any position in the circulation path may be adjusted or controlled.

[0082] ≪Program≫ The present invention may be implemented by supplying a program that implements one or more of the functions of the above embodiments to a system or device via a network or storage medium, and by a process in which one or more processors in the computer of the system or device read and execute the program. For example, the present invention may be implemented by a circuit (e.g., an ASIC) that implements one or more functions.

[0083] ≪Other≫ In the embodiments, individual elements are named using expressions based on their primary function; however, the functions described in the embodiments may also be secondary functions, and the expressions are not strictly limited to these. Furthermore, these expressions can be replaced with other similar expressions.

[0084] Furthermore, the two or more elements exemplified as selectable in the embodiment are not strictly limited to those examples and may be combined arbitrarily. For example, each of the two or more exemplified elements may be additionally selected or substituted for others. For example, when arbitrarily combining two elements A and B, it may be expressed as "A and / or B" or "at least one of A and B" to indicate that it is either A only, B only, or both A and B.

[0085] Furthermore, the expressions such as standards, standard values, permissible values, upper limits, lower limits, and permissible ranges shown in the embodiments are predetermined for comparison with the subject, and they may be replaced with other expressions to distinguish them from one another, or they may be distinguished from one another by adding "first," "second," etc.

[0086] Summary of the Embodiments Some of the features illustrated in the above embodiments are as follows: <Item 1> A recording head that records by ejecting ink, A recording device comprising a circulation mechanism for circulating ink within an ink circulation channel that passes through the recording head, A means for determining the ejection speed of ink droplets from the recording head, The system further comprises control means for controlling the drive of the circulation mechanism based on the identification result of the identification means. A recording device characterized by the following features.

[0087] <Item 2> The control means controls the drive of the circulation mechanism so that the discharge speed, which is determined by the identification means, falls within a reference range. A recording device as described in item 1, characterized by the features described herein.

[0088] <Item 3> The control means modifies the driving force for circulating the ink so that the ejection speed, as determined by the identification means, falls within a reference range. A recording device according to item 2, characterized in that it is a recording device.

[0089] <Item 4> The control means performs the change of the driving force a predetermined number of times. The recording device further includes notification means for notifying when the driving force has been changed a predetermined number of times. A recording device as described in item 3, characterized by the features described herein.

[0090] <Item 5> The circulation mechanism includes a circulation pump disposed in the circulation channel, The control means changes the drive frequency of the circulation pump. A recording device according to any one of items 1 to 4, characterized by the above.

[0091] <Item 6> The control means further changes the duty cycle of the drive signal for the circulation pump. A recording device as described in item 5, characterized by the features described herein.

[0092] <Item 7> The circulation mechanism includes a circulation pump disposed in the circulation channel, The control means changes the duty cycle of the drive signal for the circulation pump. A recording device according to any one of items 1 to 4, characterized by the above.

[0093] <Item 8> The circulation mechanism includes a circulation pump disposed in the circulation channel, The control means changes the voltage value of the drive signal for the circulation pump. A recording device according to any one of items 1 to 4, characterized by the above.

[0094] <Item 9> The circulation mechanism includes a circulation pump disposed in the circulation channel, The control means modifies the rise edge and fall edge times of the drive signal for the circulation pump. A recording device according to any one of items 1 to 4, characterized by the above.

[0095] <Item 10> A storage means for storing the history of drive control of the circulation mechanism by the control means based on the identification result of the identification means, The system further comprises a means for notifying the user of the timing of maintenance based on the history stored in the storage means. A recording device according to any one of items 1 to 9, characterized by the above.

[0096] <Item 11> The system further comprises a calculation means that calculates an approximate curve of the set value for the drive control of the circulation mechanism based on the history stored by the storage means, and calculates the time until the approximate curve reaches the upper limit of the set value. A recording device as described in item 10, characterized by the features described herein.

[0097] <Item 12> The storage means further stores as a second history the history of the discharge speed identified by the identification means after the set value for the drive control of the circulation mechanism has reached the upper limit of the set value, The notification means notifies the maintenance schedule based on the second history stored by the storage means. A recording device according to item 10 or 11, characterized in that it is a recording device.

[0098] <Item 13> The control means controls the drive of the circulation mechanism so that the discharge speed specified by the identification means falls within a reference range. If the discharge speed is not within the standard range, and the discharge speed deviates by more than the standard, the notification means will notify that maintenance is required. A recording device according to any one of items 10 to 12, characterized by the above.

[0099] <Item 14> The aforementioned recording head performs recording by ejecting multiple colors of ink. The circulation mechanism and circulation channel are provided for each ink color. The aforementioned identification means identifies the ejection speed for each ink color, The control means performs drive control of the circulation mechanism for each ink color. A recording device according to any one of items 1 to 13, characterized by the above.

[0100] <Item 15> The aforementioned recording head performs recording by ejecting multiple colors of ink. The circulation mechanism and circulation channel are provided for each ink color. The aforementioned identification means identifies the ejection speed for a certain color of ink, The control means controls the drive of the circulation mechanism for each of the multiple colors based on the result of the identification means. A recording device according to any one of items 1 to 13, characterized by the above.

[0101] <Item 16> The system further includes a means for receiving print jobs to instruct the execution of recording, The identification means determines the ejection speed in response to the receiving means receiving a print job. A recording device according to any one of items 1 to 15, characterized by the above.

[0102] <Item 17> It further includes a detection means for detecting ambient temperature, The identification means determines the discharge speed based on the detection result of the detection means. A recording device according to any one of items 1 to 16, characterized by the above.

[0103] <Item 18> Equipped with further timing means, The aforementioned identification means determines the discharge speed based on the timing result of the timing means. A recording device according to any one of items 1 to 17, characterized by the above.

[0104] <Item 19> The aforementioned identification means includes an optical sensor. A recording device according to any one of items 1 to 18, characterized by the above.

[0105] <Item 20> The aforementioned identification means includes an electrostatic sensor. A recording device according to any one of items 1 to 18, characterized by the above.

[0106] <Item 21> The aforementioned recording head is a serial head, The identification means determines the ejection speed based on the pattern recorded by the recording scan of the serial head. A recording device according to any one of items 1 to 18, characterized by the above.

[0107] <Item 22> A program that causes a computer to function as one of the recording devices described in any one of items 1 through 21.

[0108] <Item 23> A method for driving a recording device comprising a recording head that performs recording by ejecting ink, and a circulation mechanism that circulates ink in an ink circulation channel that passes through the recording head, A step of determining the ejection speed of ink droplets from the recording head, The step of controlling the drive of the circulation mechanism based on the specified discharge speed is included. A driving method characterized by the following.

[0109] The invention is not limited to the embodiments described above, and various modifications and variations are possible without departing from the spirit and scope of the invention. Accordingly, claims are attached to disclose the scope of the invention. [Explanation of Symbols]

[0110] 100: Recording device, 102: Recording head, 500: Circulation pump.

Claims

1. A recording head that records by ejecting ink, A recording device comprising a circulation mechanism for circulating ink within an ink circulation channel that passes through the recording head, A means for determining the ejection speed of ink droplets from the recording head, The system further comprises control means for controlling the drive of the circulation mechanism based on the identification result of the identification means. A recording device characterized by the following features.

2. The control means controls the drive of the circulation mechanism so that the discharge speed, which is determined by the identification means, falls within a reference range. The recording device according to feature 1.

3. The control means modifies the driving force for circulating the ink so that the ejection speed, as determined by the identification means, falls within a reference range. The recording device according to feature 2.

4. The control means performs the change of the driving force a predetermined number of times. The recording device further includes notification means for notifying when the driving force has been changed a predetermined number of times. The recording device according to feature 3.

5. The circulation mechanism includes a circulation pump disposed in the circulation channel, The control means changes the drive frequency of the circulation pump. The recording device according to feature 1.

6. The control means further changes the duty cycle of the drive signal for the circulation pump. The recording device according to feature 5.

7. The circulation mechanism includes a circulation pump disposed in the circulation channel, The control means changes the duty cycle of the drive signal for the circulation pump. The recording device according to feature 1.

8. The circulation mechanism includes a circulation pump disposed in the circulation channel, The control means changes the voltage value of the drive signal for the circulation pump. The recording device according to feature 1.

9. The circulation mechanism includes a circulation pump disposed in the circulation channel, The control means modifies the rise edge and fall edge times of the drive signal for the circulation pump. The recording device according to feature 1.

10. A storage means for storing the history of drive control of the circulation mechanism by the control means based on the identification result of the identification means, The system further comprises a means for notifying the user of the timing of maintenance based on the history stored in the storage means. The recording device according to feature 1.

11. The system further comprises a calculation means that calculates an approximate curve of the set value for the drive control of the circulation mechanism based on the history stored by the storage means, and calculates the time until the approximate curve reaches the upper limit of the set value. The recording device according to feature 10.

12. The storage means further stores as a second history the history of the discharge speed identified by the identification means after the set value for the drive control of the circulation mechanism has reached the upper limit of the set value. The notification means notifies the maintenance schedule based on the second history stored by the storage means. The recording device according to feature 10.

13. The control means controls the drive of the circulation mechanism so that the discharge speed specified by the identification means falls within a reference range. If the discharge speed is not within the standard range, and the discharge speed deviates by more than the standard, the notification means will notify that maintenance is required. The recording device according to feature 10.

14. The aforementioned recording head performs recording by ejecting multiple colors of ink. The circulation mechanism and circulation channel are provided for each ink color. The aforementioned identification means identifies the ejection speed for each ink color, The control means performs drive control of the circulation mechanism for each ink color. The recording device according to feature 1.

15. The aforementioned recording head performs recording by ejecting multiple colors of ink. The circulation mechanism and circulation channel are provided for each ink color. The aforementioned identification means identifies the ejection speed for a certain color of ink, The control means controls the drive of the circulation mechanism for each of the multiple colors based on the result of the identification means. The recording device according to feature 1.

16. The system further includes a means for receiving print jobs to instruct the execution of recording, The identification means determines the ejection speed in response to the receiving means receiving a print job. The recording device according to feature 1.

17. It further includes a detection means for detecting ambient temperature, The identification means determines the discharge speed based on the detection result of the detection means. The recording device according to feature 1.

18. Equipped with further timing means, The aforementioned identification means determines the discharge speed based on the timing result of the timing means. The recording device according to feature 1.

19. The aforementioned identification means includes an optical sensor. The recording device according to feature 1.

20. The aforementioned identification means includes an electrostatic sensor. The recording device according to feature 1.

21. The aforementioned recording head is a serial head, The identification means determines the ejection speed based on the pattern recorded by the recording scan of the serial head. The recording device according to feature 1.

22. A program that causes a computer to function as one of the means of a recording device according to any one of claims 1 to 21.

23. A method for driving a recording device comprising a recording head that performs recording by ejecting ink, and a circulation mechanism that circulates ink in an ink circulation channel that passes through the recording head, A step of determining the ejection speed of ink droplets from the recording head, The step of controlling the drive of the circulation mechanism based on the specified discharge speed is included. A driving method characterized by the following.

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