JP2020199730A - Inkjet recording device - Google Patents

Abstract

To provide an inkjet recording device which can stably suppress clogging of a nozzle due to precipitation and coagulation of pigment for a long period of time so as to secure constant performance even when ink is not used for a long time.SOLUTION: An inkjet recording device comprises an ink discharge part having ink, a particle size measurement part, a calculation part, and a return processing part. The particle size measurement part measures a particle size of pigment contained in ink which exists in at least any of an ink tank attached to a device main body, a flow path communicating the ink tank with the ink discharge part, and the ink discharge part. The calculation part calculates a threshold as a reference for evaluating a coagulation degrees of the pigment, using the particle size of the pigment and a parameter showing a property of the ink stored in a storing part that the device main body has or in an information holding part of the ink tank. The return processing part performs return processing for stirring the ink or discharging the ink through the nozzle of the ink discharge part, on the basis of the particle size of the pigment and the threshold.SELECTED DRAWING: Figure 3

Description

The present invention relates to an inkjet recording device that ejects ink onto a recording medium and records an image.

In an inkjet recording device that ejects ink containing a pigment and records an image on a recording medium, the nozzle that ejects the ink is clogged when the pigment aggregates and the dispersed state in the dispersion medium deteriorates. Therefore, Patent Document 1 attempts to suppress nozzle clogging by appropriately defining the particle size of the ink pigment.

On the other hand, in Patent Document 2, in an inkjet printing material for an illuminated signboard, by appropriately defining the total light transmittance, it is possible to print properly with an inkjet printer, and even if it is installed on the illuminated signboard, the hue in the daytime and at nighttime. There is no difference in color development and water resistance.

JP-A-2010-159355 Japanese Unexamined Patent Publication No. 2003-241693

By the way, when a long period of time has passed since the recording of the image (first recording) by ejecting the ink is completed, the particle size of the pigment increases due to the precipitation and aggregation of the pigment of the ink. Therefore, the nozzle is likely to be clogged when recording an image (second recording) by the next ink ejection.

In recent years, instead of recording images using genuine ink tanks filled with genuine ink, images using non-genuine ink tanks filled with non-genuine ink and genuine ink tanks filled with non-genuine ink have been used. Records are also being made. Some non-genuine inks are more likely to cause pigment settling and agglomeration over time than genuine inks. Therefore, even when such non-genuine ink is used, it is conceivable that the particle size of the pigment increases with the passage of time from the first recording, and the nozzle is clogged during the second recording. ..

In this regard, although Patent Document 1 mentions that the particle size of the pigment of the ink is defined to prevent clogging of the nozzle as described above, the particle size of the pigment with the passage of time is mentioned. No changes have been investigated, much less clogging of the nozzles due to changes in pigment particle size over time. Therefore, with the method of Patent Document 1, it is difficult to stably suppress nozzle clogging for a long period of time.

Further, in Patent Document 2, the transmittance of the ink is evaluated from the viewpoint of the characteristics of the printed matter, but it is not used as a parameter for evaluating the state of the ink. For this reason, for example, in the case of ink in a special state in which the pigment may settle and aggregate after being unused for a long period of time, the light-colored ink (the ratio of the dispersion medium is larger than that of the pigment) is ejected first and then Indeed, a situation occurs in which dark ink (the proportion of pigment is larger than that of the dispersion medium) is ejected, and it becomes difficult to exhibit a certain performance (in the above example, the color density is kept constant). ..

In view of the above problems, the present invention can monitor the particle size of the pigment of the ink, stably suppress the clogging of the nozzle due to the sedimentation and aggregation of the pigment for a long period of time, and the non-use period of the ink. It is an object of the present invention to provide an inkjet recording apparatus capable of ensuring a certain level of performance even if the length becomes long.

In order to achieve the above object, the ink jet recording device according to one aspect of the present invention communicates the ink ejection unit having a nozzle with the ink tank and the ink ejection unit in the ink tank mounted on the main body of the apparatus. A particle size measuring unit for measuring the particle size of a pigment contained in at least one of the inks in the flow path and the ink ejection unit, the particle size of the pigment, and a storage unit or the ink tank of the apparatus main body. Using the parameters indicating the characteristics of the ink held in the information holding unit of the above, the calculation unit for calculating the reference threshold for evaluating the degree of aggregation of the pigment, and the particle size and the threshold of the pigment. Based on this, the ink is provided with a return processing unit that stirs the ink or performs a return process of ejecting the ink from the nozzle of the ink ejection unit.

The particle size of the pigment of the ink is measured and monitored, and the restoration process (stirring or discharging of the ink) is performed based on the measured particle size of the pigment and the threshold value as a reference for evaluating the degree of aggregation of the pigment. .. As a result, for example, even if the ink is not used for a long period of time and the particle size is increased due to sedimentation and aggregation of the pigment, the particle size of the pigment is reduced by the restoration treatment, or the ink containing the pigment having the increased particle size is discharged. Since it is discarded, clogging of the nozzle can be stably suppressed for a long period of time. Further, since the restoration process can keep the ink state (particularly the dispersed state of the pigment) constant for a long period of time, the performance is constant even if the ink is not used for a long period of time (for example, a constant color density over a long period of time). It is possible to secure the above.

It is explanatory drawing which shows the schematic structure of the inkjet recording apparatus which concerns on one Embodiment of this invention. It is a top view of the ink ejection part included in the said inkjet recording apparatus. It is a block diagram which shows typically the structure of the main part of the said inkjet recording apparatus. It is explanatory drawing which shows typically the schematic structure of the particle size measuring part included in the said inkjet recording apparatus. It is explanatory drawing which shows typically how the ink meniscus of the ink ejection part vibrates. It is a flowchart which shows an example of the operation in the said inkjet recording apparatus. It is a flowchart which shows other example of the operation in the said inkjet recording apparatus. It is a flowchart which shows still another example of the operation in the said inkjet recording apparatus.

[1. Schematic configuration of an inkjet recording device]
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is an explanatory diagram showing a schematic configuration of an inkjet recording device 100 according to an embodiment of the present invention. The inkjet recording device 100 is an inkjet printer that ejects ink onto a recording medium and records an image. In the present embodiment, the ink is a water-based ink in which a pigment is dispersed in a dispersion medium.

The inkjet recording apparatus 100 has a paper feed cassette 2 as a paper accommodating portion arranged below the inside of the apparatus main body 100a. Paper P as a recording medium is housed inside the paper feed cassette 2. The paper feed device 3 is arranged on the downstream side of the paper feed cassette 2 in the paper transport direction, that is, above the left side of the paper feed cassette 2 in FIG. By the paper feeding device 3, the paper P is separated and sent out one by one toward the upper left side of the paper feed cassette 2 in FIG.

Further, the apparatus main body 100a is provided with a first paper transport path 4a. The first paper transport path 4a is located on the upper left side of the paper feed cassette 2. The paper P sent out from the paper feed cassette 2 is vertically upwardly conveyed along the side surface of the apparatus main body 100a by the first paper conveying path 4a.

A resist roller pair 5 is arranged at the downstream end of the first paper transport path 4a with respect to the paper transport direction. Further, the first belt transport unit 6 and the ink ejection unit 7 are arranged in the immediate vicinity of the resist roller pair 5 on the downstream side in the paper transport direction. The paper P sent out from the paper feed cassette 2 reaches the resist roller pair 5 through the first paper transport path 4a. The resist roller pair 5 temporarily stops the paper P to correct the oblique feed, measures the timing with the ink ejection operation executed by the ink ejection unit 7, and retransmits the paper P toward the first belt conveying unit 6. To do.

The second belt transport unit 8 is arranged on the downstream side (right side in FIG. 1) of the first belt transport unit 6 with respect to the paper transport direction. The paper P on which the ink image is recorded by the ink ejection unit 7 is sent to the second belt transport unit 8, and while passing through the second belt transport unit 8, the ink ejected on the surface of the paper P is dried. To.

A decaler portion 9 is provided on the downstream side of the second belt transport portion 8 with respect to the paper transport direction and in the vicinity of the right side surface of the apparatus main body 100a. The paper P whose ink has been dried by the second belt transport unit 8 is sent to the decaler unit 9, and curls generated on the paper P are corrected by using a plurality of rollers arranged in the paper width direction.

A second paper transport path 4b is provided on the downstream side (upper side of FIG. 1) of the decaler portion 9 with respect to the paper transport direction. When double-sided recording is not performed, the paper P that has passed through the decaler portion 9 is discharged from the second paper transport path 4b to the paper discharge tray 10 provided outside the right side surface of the apparatus main body 100a via the discharge roller pair.

Further, a maintenance device 11 is arranged below the second belt transport unit 8. The maintenance device 11 includes a maintenance unit 11a and a cap unit 11b. The maintenance unit 11a horizontally moves below the ink ejection unit 7 when executing the purge described later, and wipes off the ink extruded from the nozzles 18 (see FIG. 2) of the recording heads 17a to 17c described later. Collect the ink. When capping the ink ejection surfaces of the recording heads 17a to 17c, the cap unit 11b moves horizontally below the ink ejection unit 7 and further moves upward to be mounted on the lower surfaces of the recording heads 17a to 17c.

FIG. 2 is a plan view of the ink ejection unit 7. The ink ejection unit 7 includes a head housing 12 and line heads 13C, 13M, 13Y, and 13K held in the head housing 12. The line heads 13C, 13M, 13Y, and 13K are inkjet heads that eject inks of each color of cyan (C), magenta (M), yellow (Y), and black (K) toward the paper P, respectively.

These line heads 13C to 13K have a predetermined interval (for example,) with respect to the transport surface of the first transport belt 16 stretched on a plurality of rollers including the drive roller 14 and the driven roller 15 of the first belt transport unit 6. It is supported at a height such that 1 mm) is formed. The line heads 13C to 13K each have a plurality of (here, three) recording heads 17a to 17c. The recording heads 17a to 17c are arranged in a paper width direction (vertical direction in FIG. 2) orthogonal to the paper transport direction (arrow A direction) and are arranged in a staggered pattern. The line heads 13C to 13K have a recording area equal to or larger than the width of the paper P to be conveyed, and the recording heads 17a to 17c corresponding to the printing position with respect to the paper P conveyed by the first transfer belt 16. Ink is ejected from the nozzle 18. As a result, a color image in which inks of each color are superimposed is formed on the paper P. The line heads 13C to 13K may be of either a piezo type or a thermal type, but here, the piezo type is assumed as an example.

In the present embodiment, the ink ejection unit 7 is configured to include four line heads 13C to 13K corresponding to four colors, but is composed of only the line heads 13K corresponding to black (K), for example. You may. That is, the ink ejection unit 7 may be configured to include a number of inkjet heads corresponding to at least one color.

[2. Configuration of main parts of inkjet recording device]
FIG. 3 is a block diagram schematically showing the configuration of a main part of the inkjet recording device 100. The ink tank 101 is loaded into the apparatus main body 100a of the inkjet recording apparatus 100. The ink tank 101 is an ink cartridge (ink container) that is removable (replaceable) with respect to the apparatus main body 100a, and houses ink of a color corresponding to the line heads 13C to 13K of the ink ejection unit 7.

An information holding unit 101a is attached to the ink tank 101. The information holding unit 101a is composed of, for example, an RFID tag or an IC chip, and shows, for example, manufacturing information about the manufacturer of the ink tank 101 (for example, manufactured by company A) and the characteristics of the ink contained in the ink tank 101. It stores parameters (characteristic information). The above parameters include, for example, ink color, density, transmittance, pigment density, dispersion medium density, dispersion medium viscosity for each temperature, and constants depending on the configuration of the device (corresponding to the device constant K described later). ) And other information are included.

In addition to the ink ejection unit 7 described above, the device main body 100a of the inkjet recording device 100 includes a particle size measuring unit 21, a storage unit 22, a temperature sensor 23, a recovery processing unit 24, a warning unit 25, and a time measuring unit. A 26, a reading unit 27, and a control unit 28 are provided.

The particle size measuring unit 21 measures the particle size of the pigment contained in the ink. FIG. 4 is an explanatory diagram schematically showing a schematic configuration of the particle size measuring unit 21. The particle size measuring unit 21 includes a light emitting unit 21a, a detecting unit 21b, and a particle size calculating unit 21c.

The light emitting portion 21a is a light source that is located opposite to the transparent window portion 102a provided at the bottom of the ink tank 101 and emits light toward the ink 200 in the ink tank 101 through the window portion 102a. Here, for example, when a window portion is provided on the side portion of the ink tank 101, the interface portion between the ink 200 and the air in the ink tank 101 hits the window portion, so that the window portion becomes dirty and the light transmitted through the window portion is emitted. There is a possibility that the measurement accuracy of the light receiving detection unit 21b will decrease. Since the window portion 102a is provided at the bottom of the ink tank 101, the interface does not hit the window portion 102a and the window portion 102a is not contaminated. Therefore, it is possible to suppress a decrease in measurement accuracy due to the contamination of the window portion 102a. Can be done.

The detection unit 21b receives the light emitted from the light emitting unit 21a and transmitted through the ink 200 through the window unit 102b provided on the upper part of the ink tank 101, so that the transmitted light intensity or the scattered light intensity of the ink 200 is received. It is a sensor that detects. The particle size calculation unit 21c is composed of, for example, a CPU, and the transmitted light intensity or scattered light intensity detected by the detection unit 21b and the information (characteristics) of the ink 200 stored in the information holding unit 101a or the storage unit 22 of the ink tank 101. The particle size of the pigment contained in the ink 200 is calculated based on the information or parameters).

For example, the absorbance obtained from the transmitted light intensity A of the ink is I, the particle size of the pigment contained in the ink is d (cm), the density of the ink is C% (known), and the device constant is K (known). Then, it is known that the relationship of d × I × C = K holds. Therefore, the particle size d of the pigment can be obtained from the above formula by detecting the transmitted light intensity A of the ink. The absorbance I at the wavelength λ is determined by I = −log ₁₀ (A / A ₀ ). Here, A ₀ indicates the incident light intensity (emission intensity). The device constant K described above varies depending on the drying speed of the head (depending on the nozzle spacing, etc.) in addition to the parameters for calculating the settling speed, which will be described later, and therefore is a value depending on the configuration of the device. Become.

It is also known that the particle size of the pigment can be estimated from a model formula such as Mie scattering. Therefore, the particle size calculation unit 21c can estimate and obtain the particle size of the pigment based on the known model formula and the measured scattered light intensity.

The ink for which the particle size measuring unit 21 measures the particle size of the pigment is not limited to the ink 200 in the ink tank 101. By appropriately changing the positions of the light emitting unit 21a and the detection unit 21b, the particle size measuring unit 21 can measure the particle size of the ink pigment in the ink ejection unit 7, and the ink tank 101 and the ink ejection unit 7 can be measured. It is also possible to measure the particle size of the ink pigment in the flow path 31 that communicates with. In addition, the particle size measuring unit 21 can also measure the particle size of the ink pigment in all the flow paths in the apparatus main body 100a. Sub-tanks, pumps, and the like are provided between the ink tank 101 and the ink ejection unit 7, but they are not shown in FIG.

The storage unit 22 is a memory that stores various data in addition to the operation program of the control unit 28. The above data includes parameters indicating the characteristics of the ink. The above parameters include the color, density, transmittance, pigment density, dispersion medium density, dispersion medium viscosity for each temperature, and the above-mentioned parameters, which are the same as the parameters held in the information holding unit 101a of the ink tank 101. Characteristic information such as device constant K is included. Such a storage unit 22 is appropriately selected from a ROM, a RAM, a hard disk, a portable storage medium, and the like.

The temperature sensor 23 measures the internal temperature of the apparatus main body 100a. Such a temperature sensor 23 can be configured by a thermistor or the like.

When the particle size of the pigment increases due to the precipitation and aggregation of the pigment in the ink, the restoration processing unit 24 performs a restoration treatment for returning the ink to the state before the particle size of the pigment increases. In the above restoration treatment, an ink having an increased particle size of the pigment is stirred to redisperse the pigment (redispersion treatment), or an ink having an increased particle size of the pigment is agitated from the nozzle 18 (see FIG. 2). Includes a purge process to throw away.

Such a restoration processing unit 24 includes a stirring unit 30 for stirring the ink. The stirring unit 30 is composed of, for example, an ultrasonic wave generator 30a and a drive circuit 30b (driving unit) that drives the ink ejection unit 7. For example, the pigment can be redispersed by vibrating and stirring at least one of the inks in the ink tank 101 and the flow path 31 by the ultrasonic waves generated by the ultrasonic wave generator 30a. Further, the drive circuit 30b supplies a drive signal to the piezoelectric element of the ink ejection unit 7 to transmit the pressure to the ink in the ink ejection unit 7 (for example, the pressure chamber), and as shown in FIG. 5, the inside of the nozzle 18 By vibrating the surface of the ink ejection side (hereinafter, referred to as ink meniscus M), the ink in the ink ejection portion 7 can be agitated. The drive of the ultrasonic wave generator 30a is controlled by the stirring control unit 28c of the control unit 28, and the drive of the drive circuit 30b is controlled by the drive control unit 28d of the control unit 28. That is, the return processing unit 24 includes a stirring unit 30, a stirring control unit 28c, and a drive control unit 28d.

Further, the drive control unit 28d can also control the ink ejection unit 7 by the drive circuit 30b to execute a purge process of ejecting ink having an increased particle size of the pigment from the nozzle 18.

The warning unit 25 issues an external warning (alert) as necessary to notify the user of the abnormality. Such a warning unit 25 includes a display unit 25a (for example, a liquid crystal display device of an operation panel) for displaying a warning and a warning sound output unit 25b (for example, a speaker) for outputting a warning sound. The operation of the warning unit 25 is controlled by the warning control unit 28e. The timekeeping unit 26 is composed of a timer that measures the time. For example, the operating time of the inkjet recording device 100, the elapsed time from the immediately preceding return process, and the like are timed by the time measuring unit 26.

The reading unit 27 accesses the information holding unit 101a of the ink tank 101 to read the manufacturing information regarding the manufacturer of the ink tank 101 and the characteristic information indicating the characteristics of the ink contained in the ink tank 101. Such a reading unit 27 can be configured by, for example, a reader / writer that reads / writes information to / from the information holding unit 101a.

The control unit 28 is composed of, for example, a CPU, and operates according to an operation program stored in the storage unit 22. In addition to the main control unit 28a that controls the operation of each unit of the inkjet recording device 100, such a control unit 28 includes a calculation unit 28b, a stirring control unit 28c, a drive control unit 28d, and a warning control unit 28e. It is configured to have a determination unit 28f.

The calculation unit 28b calculates a threshold value as a reference for evaluating the degree of aggregation of the pigment based on the particle size of the pigment measured by the particle size measuring unit 21 and the parameters stored in the storage unit 22. The details of the method of calculating the threshold value will be described later.

The determination unit 28f determines whether or not the ink tank 101 mounted on the apparatus main body 100a is a genuine product based on the parameters stored in the storage unit 22 and the manufacturing information and characteristic information read by the reading unit 27. And, it is determined whether or not the ink contained in the ink tank 101 is genuine ink. For example, the determination unit 28f determines whether or not the information such as the color of the ink, the transmittance, and the particle size of the pigment is matched or not, based on the parameters stored in the storage unit 22 and the characteristic information read by the reading unit 27. This makes it possible to determine whether or not the ink tank 101 is a genuine product and whether or not the ink in the mounted ink tank 101 is genuine ink.

[3. About the operation of the inkjet recording device]
FIG. 6 is a flowchart showing an example of the operation of the inkjet recording device 100 of the present embodiment. Here, it is assumed that the storage unit 22 of the apparatus main body 100a stores in advance parameters indicating the characteristics of the genuine ink. Further, it is assumed that the information holding unit 101a of the ink tank 101 stores in advance the manufacturing information of the ink tank 101 and the parameters (characteristic information) indicating the characteristics of the ink contained in the ink tank 101.

First, when the power of the apparatus is turned on, the particle size measuring unit 21 measures the particle size of the ink pigment in the ink tank 101 (S1). That is, the light emitting unit 21a emits light toward the ink 200 in the ink tank 101 through the window portion 102a provided in the ink tank 101, and the light scattered by the ink 200 or transmitted through the ink 200 is emitted. By receiving light from the detection unit 21b, the scattered light intensity or the transmitted light intensity of the ink 200 is detected. The particle size calculation unit 21c describes the scattered light intensity or transmitted light intensity and the parameters of the ink held in the storage unit 22 or the information holding unit 101a by a known relational expression (d × I × C = K described above). , Or the model formula of Mie scattering) to calculate the particle size d of the pigment contained in the ink 200. The reading unit 27 accesses the information holding unit 101a of the ink tank 101 from the device main body 100a side (hereinafter, the same applies).

Next, the calculation unit 28b uses the particle size of the pigment obtained in S1 and the parameters held in the storage unit 22 or the information holding unit 101a to use a threshold value (third threshold value) as a reference for evaluating the degree of aggregation of the pigment. The threshold value of 1 and the second threshold value) are calculated (S2). Hereinafter, the method of calculating the threshold value will be described in detail.

In general, in a slurry dispersion, if the moving speed in the vertical direction (vertical direction) due to Brownian motion is sufficiently higher than the settling speed of the pigment particles, they do not agglomerate practically. Assuming that the sedimentation velocity of the former pigment particles is v1 (cm / s), the sedimentation velocity v1 can be calculated by the equation (1). In Equation 1, ρs is the density of pigment particles (g / cm ³ ), ρw is the density of dispersion medium (g / cm ³ ), g is gravitational acceleration (cm / s ² ), and d is the particle size of the pigment. (Cm), C _d is the resistance coefficient of the pigment.

On the other hand, assuming that the motion velocity in the vertical direction due to the latter Brownian motion is v2 (cm / s), the motion velocity v2 can be calculated by the following equation (2). Note that in equation (2), R represents the gas constant (8.31J / (K · mol) ), N A is Avogadro constant ^{(6.022 × 10 23 / mol)} , η is the viscosity of the dispersion medium (Pa · s) , T is the temperature (K).

Therefore, in order for the pigments to not aggregate, it is necessary to control the particle size d of the pigments so as to satisfy the following equation (3) derived from v1 <v2. The right side of the equation 3 indicates a numerical value relating to the stability of dispersion, and K'is a device constant determined by the device configuration.

In order to improve the accuracy of the determination by the return processing unit 24 whether or not the return processing is performed, the calculation unit 28b sets the numerical value on the right side of the equation 3 as L (cm), and sets a value smaller than the numerical value L as the presence or absence of the return processing. It is set as a threshold value used for judgment. More specifically, the calculation unit 28b sets 0.1 L, which is smaller than L, as the first threshold value, and 0.8 L, which is larger than 0.1 L and smaller than L, as the second threshold value. Set. In addition, η of the equation 3 is the viscosity of the dispersion medium at the temperature measured by the temperature sensor 23.

Here, in S1, when the particle size of the pigment cannot be measured by the particle size measuring unit 21 for some reason, and in S2, when the threshold value cannot be set (calculated) for some reason (S3). No), the warning control unit 28e determines that irregular ink is being used, and controls the warning unit 25 to give an alert to the outside (S4). By this control, for example, the display unit 25a displays a warning such as "The print quality may deteriorate due to the use of irregular ink", or a voice warning to that effect is given. It is emitted from the sound output unit 25b.

When the particle size of the pigment cannot be measured and the threshold value cannot be calculated, for example, (a) when a refilled product in which non-genuine ink is injected into a genuine ink tank is used, (b) the ink is used for some reason. It is assumed that the solid component is almost eliminated, or (c) there is a problem with the parameter written to the information holding unit 101a of the ink tank 101. In particular, in the case of the above (a), there is a risk of the pigment agglutinating due to a shock when the pigment is mixed with the solvent, and in the case of the above (b), the ink is not formed in the first place, so it is necessary to stop printing.

On the other hand, if the particle size of the pigment can be measured in S1 and the threshold value can be set (calculated) in S2 (Yes in S3), the restoration processing unit 24 is the pigment measured by the particle size measuring unit 21. The necessity of the return processing is determined based on the particle size d and the threshold values (first threshold value, second threshold value) set by the calculation unit 28b, and the return processing is performed as necessary (S5 to S7). .. More details are as follows.

(1) When d <0.1L When the particle size d of the pigment measured by the particle size measuring unit 21 is smaller than the first threshold value (0.1L) (No in S5), the restoration processing unit 24 (No) In particular, the stirring control unit 28c and the drive control unit 28d) determine that a good ink in which the pigment is not aggregated is used, and do not perform a recovery process in particular (printing is performed using the ink as it is).

(2) When 0.1L ≦ d <0.8L When the particle size d of the pigment measured by the particle size measuring unit 21 is equal to or more than the first threshold value (0.1L) and less than the second threshold value (S5). Yes, Yes in S6), the restoration processing unit 24 determines that the aggregation of the pigment is progressing, and performs the restoration processing (S7). Specifically, the stirring control unit 28c controls the ultrasonic wave generator 30a to generate ultrasonic waves, and the ink in the ink tank 101 is stirred (redispersed) by the ultrasonic waves. At this time, the drive control unit 28d controls the drive circuit 30b to transmit pressure to the ink in the ink ejection unit 7 to vibrate the ink meniscus M in the nozzle 18 to stir the ink in the ink ejection unit 7. May be good. Further, the drive control unit 28d controls the drive circuit 30b instead of stirring the ink in the ink ejection unit 7, and from the nozzle 18 of the ink ejection unit 7, the ink (ink whose particle size has increased due to the aggregation of pigments). ) May be executed by the ink ejection unit 7.

(3) When 0.8L ≦ d When the particle size d of the pigment measured by the particle size measuring unit 21 is equal to or greater than the second threshold value (0.8L) (No in S6), the restoration processing unit 24 , It is judged that there is a high possibility that the agglomeration of the pigment has progressed considerably or that dust is mixed. In response to this determination, the main control unit 28a stops the operation of the device, and the warning control unit 28e controls the warning unit 25 so as to issue an alert to the outside (S4).

[4. effect〕
As described above, in the present embodiment, the restoration processing unit 24 stirs the ink or ejects the ink from the nozzle 18 based on the particle size d of the pigment and the threshold values (first threshold value, second threshold value). Performs a return process to throw away. By stirring the ink, the pigment is redispersed and its particle size is reduced, so that clogging of the nozzle 18 can be suppressed. Further, even in the case of ejecting the ink, the ink containing the pigment having an increased particle size is forcibly ejected and eliminated, so that clogging of the nozzle 18 at the time of subsequent printing can be suppressed. Moreover, by actually measuring the particle size of the ink pigment, even if the ink is not used for a long period of time, the restoration process is performed according to the actual state (particle size) of the ink to prevent the nozzle 18 from being clogged. It can be suppressed. As a result, clogging of the nozzle 18 can be stably suppressed for a long period of time. In addition, since the restoration process can maintain the ink state (particularly the dispersed state of the pigment) well, even if the ink is not used for a long period of time, the performance is constant over a long period of time, for example, to keep the color density constant. Can be secured.

Further, when the particle size of the pigment is equal to or larger than the first threshold value, the stirring control unit 28c controls the stirring unit 30 (ultrasonic generator 30a, drive circuit 30b) to stir the ink. In this case, by redispersing the pigment, the particle size of the pigment can be brought closer to the first threshold value or less than the first threshold value, and the effect of suppressing clogging of the nozzle 18 can be surely obtained. Become.

Further, since the stirring unit 30 includes the ultrasonic wave generator 30a, the ink can be easily stirred by ultrasonic waves and the pigment can be easily redispersed.

Further, since the stirring unit 30 includes a drive circuit 30b that vibrates the ink meniscus M in the nozzle 18 of the ink discharging unit 7, the ink in the ink discharging unit 7 can be easily stirred by the vibration.

Further, the return processing unit 24 includes a drive control unit 28d, and when the particle size of the pigment is equal to or larger than the first threshold value, the ink ejection unit 7 is controlled to execute the purge process, so that the pigment having an increased particle size It is possible to forcibly remove the ink containing the above ink and control the clogging of the nozzle 18 during the subsequent printing.

Further, the warning control unit 28e alerts (warning) to the outside by the warning unit 25 (display unit 25a, warning sound output unit 25b) when the particle size of the pigment is equal to or greater than the second threshold value larger than the first threshold value. ) Is executed. Upon receiving this alert, the user can easily understand that the nozzle 18 is likely to be clogged and that a certain print quality is not guaranteed, and take appropriate measures such as replacing the ink tank 101 with a new tank. It will be possible to take.

Further, the particle size measuring unit 21 measures the scattered light intensity or the transmitted light intensity of the ink, and is based on the measured scattered light intensity or the transmitted light intensity and a parameter indicating the characteristics of the ink stored in the storage unit 22 or the like. And measure the particle size of the pigment. As a result, the particle size of the pigment can be accurately measured, so that it is possible to accurately determine the necessity of the restoration process based on the particle size and the threshold value.

Further, the particle size measuring unit 21 receives the light emitted toward the ink 200 in the ink tank 101 through the window portion 102a provided in the ink tank 101 by the detecting unit 21b, thereby causing the scattered light intensity. Or measure the transmitted light intensity. The ink tank 101 mounted on the apparatus main body 101a can be replaced with a new tank when the ink 200 is used up. Therefore, even if the window portion 102a of the old ink tank 101 is contaminated by the ink 200, after the ink tank 101 is replaced, light is directed toward the ink 200 in the ink tank 101 through the window portion 102a having almost no stain. It can be emitted. As a result, the detection unit 21b can accurately measure the scattered light intensity or the transmitted light intensity, and the measured scattered light intensity or the transmitted light intensity can be used to accurately measure the particle size of the pigment. It becomes.

Further, the calculation unit 28b determines the particle size of the pigment measured by the particle size measurement unit 21, the temperature acquired by the temperature sensor 23, and the parameters stored in the storage unit 22 or the like (the viscosity of each temperature of the dispersion medium). The first threshold (0.1L) and the second threshold (0.8L) are calculated based on (including). Since the viscosity of the dispersion medium changes depending on the temperature, the restoration process is performed based on the particle size and the threshold value of the pigment by calculating the threshold value in consideration of the viscosity of the dispersion medium at the temperature acquired by the temperature sensor 23. It becomes possible to judge the necessity more accurately.

[5. Other operations of the inkjet recording device]
FIG. 7 is a flowchart showing another example of operation in the inkjet recording device 100 of the present embodiment. In FIG. 7, the steps up to S6 are exactly the same as in FIG.

After S6, the determination unit 28f determines whether or not the ink tank 101 is a genuine product based on the parameters stored in the storage unit 22 and the manufacturing information and characteristic information read by the reading unit 27. It is determined whether or not the ink contained in the ink tank 101 is genuine ink (S6-1). When the ink tank 101 is a genuine product (when the ink contained in the ink tank 101 is genuine ink), the process proceeds to S7 and the same restoration process as in FIG. 6 is performed.

On the other hand, in S6-1, when the ink tank 101 is a non-genuine product, or when the ink tank 101 is a genuine product and the ink contained in the ink tank 101 is a non-genuine ink (for example, genuine ink). (In the case of a refilled product in which non-genuine ink is injected into the ink tank), the return processing unit 24 has a predetermined timing determined based on the operating time of the device timed by the timing unit 26 or the elapsed time from the immediately preceding return processing. , The next return processing is performed (S7-1). For example, the return processing unit 24 performs the above-mentioned return process when the operating time after the power of the apparatus is turned on reaches a predetermined time (for example, when it reaches 1 hour, and thereafter, the elapsed time from the immediately preceding return process is a predetermined time (for example). For example, the return process is performed every time the time is reached (2 hours).

In this way, when a non-genuine ink tank or non-genuine ink is used at the will of the user, the recovery processing unit 24 periodically performs the recovery processing as needed. This makes it possible to prevent the agglutination of the pigment in the non-genuine ink. As a result, even when non-genuine ink is used, it is possible to prevent clogging of the nozzle 18 and ensure a certain level of performance.

Further, FIG. 8 is a flowchart showing still another example of the operation in the inkjet recording device 100 of the present embodiment. In FIG. 8, the steps up to S6-1 are exactly the same as those in FIG. If the ink tank 101 is a genuine product in S6-1, the process proceeds to S7 and the same restoration process as in FIG. 6 is performed.

On the other hand, in S6-1, when the ink tank 101 is a non-genuine product, or when the ink tank 101 is a genuine product and the ink contained in the ink tank 101 is a non-genuine ink, the restoration process is performed. The unit 24 (particularly, the stirring control unit 28c and the drive control unit 28d) compares the particle size of the pigment acquired in S1 with a third threshold value (for example, 0.05 L) smaller than the first threshold value (S6-2). ). In S6-2, when the particle size of the pigment is equal to or larger than the third threshold value, the restoration processing unit 24 performs the restoration processing described above (S7). On the other hand, in S6-2, when the particle size of the pigment is less than the third threshold value, the restoration processing unit 24 determines that the pigment is not aggregated, does not perform the restoration processing, and ends a series of processing. ..

In this way, when a non-genuine ink tank or non-genuine ink is used according to the user's intention, the particle size of the pigment is compared with a stricter threshold value (third threshold value) than when a genuine ink tank (genuine ink) is used. However, by performing the restoration treatment based on the result, it is possible to prevent the agglomeration of the pigment in the non-genuine ink. As a result, even when non-genuine ink is used, it is possible to prevent clogging of the nozzle 18 and ensure a certain level of performance.

In the present embodiment, in S6, when the particle size of the pigment is equal to or larger than the second threshold value, the process shifts to S4 to alert the outside, but the user sets in advance. Therefore, it is also possible to perform the return processing of S7 without performing an alert, and then continue printing. That is, the user can also explicitly disable a particular action (eg, an alert) for a predetermined period of time or permanently.

The present invention can be used in an inkjet recording device that ejects ink to a storage medium and records an image.

7 Ink ejection unit 18 Nozzle 21 Particle size measurement unit 22 Storage unit 23 Temperature sensor 24 Recovery processing unit 25 Warning unit 26 Timekeeping unit 27 Reading unit 28b Calculation unit 28c Stirring control unit 28d Drive control unit 28e Warning control unit 28f Judgment unit 30 Stirring Part 30a Ultrasonic generator 30b Drive circuit (drive part)
31 Flow path 100 Ink-ink recording device 100a Device body 101 Ink tank 101a Information holding section 102a Window section M Ink meniscus

Claims (11)

Ink ejection part with nozzle and
Particle size measurement for measuring the particle size of a pigment contained in at least one of the inks in the ink tank mounted on the main body of the apparatus, in the flow path communicating the ink tank and the ink ejection portion, and in the ink ejection portion. Department and
A reference for evaluating the degree of aggregation of the pigment by using the particle size of the pigment and a parameter indicating the characteristics of the ink held in the storage unit of the apparatus main body or the information holding unit of the ink tank. The calculation unit that calculates the threshold and
It is characterized by including a recovery processing unit that agitates the ink or discharges the ink from the nozzle of the ink ejection unit based on the particle size and the threshold value of the pigment. Ink recording device. The return processing unit
A stirring unit that stirs at least one of the inks in the ink tank, the flow path, and the ink ejection unit.
A stirring control unit for controlling the stirring unit is provided.
The inkjet recording apparatus according to claim 1, wherein the stirring control unit controls the stirring unit to stir the ink when the particle size of the pigment is equal to or larger than the threshold value. The inkjet recording device according to claim 2, wherein the stirring unit includes an ultrasonic generator that agitates at least one of the inks in the ink tank and the flow path by ultrasonic waves. The stirring unit includes a driving unit that stirs the ink in the ink ejection unit by transmitting pressure to the ink in the ink ejection unit to vibrate the ink meniscus in the nozzle. The inkjet recording apparatus according to claim 2 or 3. The return processing unit includes a drive control unit that controls the ink ejection unit to execute a purging process for ejecting the ink from the nozzle when the particle size of the pigment is equal to or greater than the threshold value. The inkjet recording apparatus according to any one of claims 1 to 4. A warning section that warns the outside and
A warning control unit that controls the warning unit is further provided.
When the threshold value is the first threshold value and a threshold value larger than the first threshold value is the second threshold value,
The method according to any one of claims 1 to 5, wherein the warning control unit executes a warning to the outside by the warning unit when the particle size of the pigment is equal to or greater than the second threshold value. Inkjet recording device. The particle size measuring unit measures the scattered light intensity or the transmitted light intensity of the ink, and measures the particle size based on the measured scattered light intensity or the transmitted light intensity and the parameter. The inkjet recording apparatus according to any one of claims 1 to 6. The particle size measuring unit measures the scattered light intensity or the transmitted light intensity by receiving the light emitted toward the ink in the ink tank through the window portion provided in the ink tank. The inkjet recording apparatus according to claim 7. Further equipped with a temperature sensor to measure temperature,
The parameters include the density of the pigment, the drag coefficient of the pigment, the density of the dispersion medium, and the viscosity of the dispersion medium at each temperature.
The calculation unit according to any one of claims 1 to 8, wherein the calculation unit calculates the threshold value based on the particle size of the pigment, the temperature acquired by the temperature sensor, and the parameter. The described inkjet recording device. A timekeeping unit that measures the operating time of the inkjet recording device or the elapsed time from the immediately preceding return process.
A reading unit that accesses the information holding unit of the ink tank and reads manufacturing information about the manufacturer of the ink tank and characteristic information indicating the characteristics of the ink contained in the ink tank.
Based on the parameters stored in the storage unit, the manufacturing information read by the reading unit, and the characteristic information, whether or not the ink tank is a genuine product and the ink contained in the ink tank. It also has a judgment unit that determines whether or not the ink is genuine ink.
In the recovery processing unit, when the determination unit determines that the ink tank is a non-genuine product, or when the ink tank is determined to be a genuine product and the ink is contained in the ink tank. The following according to any one of claims 1 to 9, wherein when it is determined that the ink is non-genuine ink, the next restoration process is performed at a timing determined based on the operating time or the elapsed time. Ink recording device. A timekeeping unit that measures the operating time of the inkjet recording device or the elapsed time from the immediately preceding return process.
A reading unit that accesses the information holding unit of the ink tank and reads manufacturing information about the manufacturer of the ink tank and characteristic information indicating the characteristics of the ink contained in the ink tank.
Based on the parameters stored in the storage unit, the manufacturing information read by the reading unit, and the characteristic information, whether or not the ink tank is a genuine product and the ink contained in the ink tank. It also has a judgment unit that determines whether or not the ink is genuine ink.
In the recovery processing unit, when the determination unit determines that the ink tank is a non-genuine product, or when the ink tank is determined to be a genuine product and the ink is contained in the ink tank. Is determined to be non-genuine ink, the particle size of the pigment is compared with a third threshold value smaller than the threshold value, and when the particle size is equal to or larger than the third threshold value, the particle size is said to be the same. The inkjet recording apparatus according to any one of claims 1 to 9, wherein the restoration process is performed.

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