JP2009051110A - INJECTION STATE DETECTION DEVICE AND INJECTION STATE DETECTION METHOD - Google Patents

Abstract

A liquid ejection state is detected without using a detection element such as an optical detection element so that the formation of an ink flow path is not limited in space.
A measuring unit measures an electromotive force generated between two electrodes provided in an ink cartridge. The liquid reduction amount calculation unit 12 is recorded in the recording unit 13 and refers to the correspondence table 14 that defines the relationship between the electromotive force and the remaining amount of ink for each ink cartridge, and the ink in the ink cartridge 100 is measured from the measured electromotive force. Calculate the amount of decrease. The liquid ejection amount calculation unit 16 calculates the ejection amount of ink to be ejected in the ejection operation of the liquid ejection unit 15 configured in the carriage 20. The determination unit 17 determines whether the ratio between the ink decrease amount calculated by the liquid decrease amount calculation unit 12 and the ink ejection amount calculated by the liquid ejection amount calculation unit 16 is a value in a predetermined range. Determine. The notification unit 18 notifies the injection state based on the determination result.
[Selection] Figure 5

Description

  The present invention relates to an ejection state detection apparatus and an ejection state detection method for detecting an ejection state of a liquid with respect to a liquid ejection unit that ejects a liquid stored in a liquid storage container by an ejection operation.

  The liquid stored in the liquid container is ejected from the ejection head onto a recording medium such as paper, glass or resin substrate, or cloth, and predetermined characters, figures, or images (hereinafter collectively referred to as “collection”). In this case, a liquid ejecting apparatus that forms an image) is used. As an example of such a liquid ejecting apparatus, there is an ink jet printer that ejects ink as liquid from a ejecting head onto a recording medium to form a predetermined image on the recording medium.

  In order to form high-quality images on various recording media for inks used in inkjet printers, for example, Patent Document 1 discloses a preferred ink composition according to the recording medium. In an ink jet printer, ink is supplied to an ejection head from an ink cartridge as a liquid container that contains ink having such a preferable composition, and the supplied ink is ejected from the ejection head as an ink droplet onto a recording medium. An image is formed.

  Further, in an ink jet printer, for example, an ink flow path for supplying ink from an ink cartridge to a nozzle formed in the ejection head is formed in the ejection head. A pressure chamber is provided in the middle of the formed ink flow path, and a pressure generation mechanism using the electrostrictive property of the piezoelectric element is formed so as to apply pressure to the ink in the pressure chamber. The ink to which pressure is applied by the pressure generation mechanism is ejected as ink droplets from a nozzle located at the end of the ink flow path.

  The ejecting head is formed with a liquid ejecting means including such an ink flow path and a pressure generating mechanism, and ink droplets are ejected from the nozzles by the pressurizing operation of the pressure generating mechanism. Accordingly, in the ejection head, the ink flows smoothly through the ink flow path, and an amount of ink corresponding to the pressure applied in the pressure chamber is ejected from the nozzle as ink droplets, so that an image can be correctly formed on the recording medium. become. In other words, in order to correctly form an image on the recording medium, it is necessary that the ink contained in the ink cartridge be stably ejected from the nozzle.

  However, in an ink jet printer, air bubbles may be mixed in the ink or the viscosity of the ink may increase (thickening). At this time, if mixed bubbles or thickened ink block the ink flow path, the ink does not flow smoothly through the ink flow path, and the ink cannot be stably ejected. As a result, an image cannot be correctly formed on the recording medium.

  For this reason, in an ink jet printer, ink flow is cleaned by ejecting ink from nozzles or sucking ink at a predetermined timing such as when power is turned on. The cleaning that is performed at this time consumes ink that should originally be used for image formation. Therefore, if the cleaning is performed only when it is necessary, the amount of ink consumed other than the image formation can be suppressed.

  Therefore, conventionally, there has been proposed a technique for detecting whether or not the state of the ink in the ink flow path is a state that needs to be cleaned so that the ink flows smoothly. For example, Patent Document 2 discloses a technique for detecting the state of ink in an ink flow path. In Patent Document 2, an optical detection element is arranged at a position corresponding to an ink flow path through which ink flows in an ejection head to detect the amount and state of ink.

Japanese Patent Laid-Open No. 2003-3101 JP-A-7-232440

  However, the technique disclosed in Patent Document 2 determines whether or not ink is filled in the ink flow path. Therefore, for example, if the ink that has increased viscosity has suppressed the flow of ink in the ink flow path and the ink does not flow smoothly, the technique disclosed in Patent Document 2 cannot detect this state. It was.

  In addition, there are also problems such as securing a space for arranging the detection element in the ejection head and restricting the location of the ink flow path for detection by the detection element. In addition, there are cost increase factors such as a detection element and a circuit related to detection, and the technique is difficult to apply to an ink jet printer especially for the purpose of downsizing and cost reduction.

  By the way, it has been known for a long time that a power is generated between two electrodes by putting two electrodes having different ionization tendency into an electrolyte solution (for example, a voltaic battery). For example, the present inventors have found that an ink having a composition as disclosed in Patent Document 1 described above is a liquid that can be used as such an electrolyte solution. Accordingly, it has been found that if two electrodes with different ionization tendencies are inserted into the ink cartridge, the ink cartridge forms a voltaic battery and a voltage is generated between the two electrodes.

  Therefore, the present invention has been made to solve at least a part of the above problems by using the voltage generated in this manner in the liquid container, and can be realized as the following forms or application examples. Is possible.

  Application Example 1 A liquid ejection unit that ejects a liquid contained in a liquid container by a jetting operation, and detects an ejection state of the liquid. The liquid container includes two electrodes. And the liquid container using the measuring unit that measures the electromotive force generated between the two electrodes when the liquid is stored in the liquid container before and after the ejection operation, and the measured electromotive force. A liquid reduction amount calculation unit for calculating a reduction amount of the liquid contained in the container, a liquid injection amount calculation unit for calculating an injection amount of the liquid to be ejected by the ejection operation, and the calculated liquid reduction amount A determination unit that determines whether the ratio of the calculated liquid ejection amount is a value in a predetermined range, and based on a determination result of the determination unit, the liquid ejecting unit Squirt A notification unit that notifies the state, characterized by comprising a.

  According to this ejection state detection device, the electromotive force generated between the two electrodes of the liquid storage container is measured, and the liquid amount actually reduced in the liquid storage container is calculated using the measured electromotive force. Then, the liquid amount to be ejected by the ejection operation is calculated, and the liquid ejection state is determined and notified by comparing with the actually decreased liquid amount. As will be described later, since the electromotive force generated between the two electrodes changes in accordance with the remaining amount of the liquid, the amount of decrease in the liquid can be detected correctly. Accordingly, the ratio of the correctly detected actual liquid reduction amount and the calculated liquid ejection amount to be ejected is compared with a value in a predetermined range to correctly determine the liquid ejection state. Can be notified. In addition, since the ejection state of the liquid can be detected without using a detection element such as an optical detection element, for example, the formation of the ink flow path is not limited in space.

  Application Example 2 In the ejection state detection device, the measurement unit measures the electromotive force before and after the ejection operation for the ejection operation in which the ejection amount of the liquid becomes a predetermined value. Features.

  If it carries out like this, the injection state of a liquid will be detected for every predetermined injection amount. Therefore, for example, if the liquid ejection amount in the ejection operation is determined in advance as the smallest liquid reduction amount that causes a certain difference in the electromotive force generated in the liquid container, the liquid ejection state is frequently performed. It can be detected with high accuracy. As a result, as will be described later, the liquid ejecting means can be appropriately cleaned.

  Application Example 3 In the ejection state detection device, the determination unit includes a plurality of the predetermined ranges, and a ratio between the calculated liquid decrease amount and the calculated liquid ejection amount. Are determined for each of the ranges, and the notification unit is configured to determine the liquid ejecting unit based on a determination result of the determination unit. The ejection state of the liquid according to a plurality of ranges is notified.

  In this way, the difference between the calculated liquid ejection amount and the actual liquid decrease amount is determined in a plurality of stages, and the liquid ejection state corresponding to the determination result is notified. Therefore, the liquid ejection state can be detected in a plurality of stages. As a result, for example, it is possible to perform an appropriate jetting recovery process in accordance with the liquid jetting state in the liquid jetting means, such as appropriate cleaning according to the difficulty of ink flow in the ink flow path.

  Application Example 4 In the ejection state detection device, the apparatus includes a recording unit in which a correspondence table that defines a relationship between the amount of liquid stored in the liquid storage container and electromotive force is recorded, and the liquid reduction amount The calculation unit calculates a reduction amount of the liquid stored in the liquid storage container using the recorded correspondence table.

  In this way, using the correspondence table that defines the relationship between the amount of liquid stored in each liquid storage container and the electromotive force, the difference in the amount of liquid corresponding to the two measured electromotive forces is calculated as the amount of decrease in the liquid. Can be calculated correctly. For example, when the value of electromotive force generated by ink composition differs for ink as a liquid, a correspondence table is recorded for each ink cartridge classified based on the ink composition. Then, by using the correspondence table for the ink cartridge having the same ink composition as the ink stored in the ink cartridge that is the target for calculating the ink decrease amount, the ink decrease amount stored in the ink cartridge is correctly calculated. be able to.

  Application Example 5 In the ejection state detection device, the measurement unit is provided in the liquid container.

  If it carries out like this, the conducting wire distance which electrically guides the electromotive force which arose in the liquid container to the measurement part will become short. Therefore, since the voltage drop in the conducting wire is suppressed, it is possible to correctly measure the generated electromotive force.

  Application Example 6 In the injection state detection device, the two electrodes are formed of materials having different ionization tendencies.

  It is known that electric power is generated between two electrodes by putting two electrodes having different ionization tendencies in an electrolyte solution (for example, a voltaic battery). The inventors have found that an ink having a composition as disclosed in Patent Document 1 described above is a liquid that can be used as such an electrolyte solution. Therefore, if two electrodes having different ionization tendencies are inserted into the ink cartridge, the ink cartridge can form a voltaic battery and generate an electromotive force between the two electrodes.

  Application Example 7 A liquid ejection unit that ejects the liquid stored in the liquid storage container by a spraying operation. The liquid storage container includes two electrodes. And measuring the electromotive force generated between the two electrodes by storing the liquid in the liquid storage container before and after the ejection operation, and using the measured electromotive force, the liquid storage A liquid decrease amount calculating step for calculating a decrease amount of the liquid contained in the container, a liquid injection amount calculating step for calculating an injection amount of the liquid to be ejected by the ejection operation, and the calculated liquid decrease amount A determination step for determining whether the ratio of the calculated liquid ejection amount is a value within a predetermined range, and a determination result in the determination step, the liquid ejection means is attached to the liquid ejection means. Injection detecting method characterized by comprising a notification step of notifying the ejection state of the liquid.

  According to this injection state detection method, it is possible to obtain the same effects as those of the injection state detection device described in [Application Example 1]. In addition, this injection state detection method may add a process required to be performed in the injection state detection apparatus which has the aspect in each application example mentioned above.

  Next, this invention is demonstrated based on an Example. FIG. 1 shows a schematic structure of an ink jet printer 10 which is an embodiment of a liquid ejecting apparatus incorporating the ejecting state detecting apparatus of the present invention. Further, the figure shown in the lower blowing part in the figure is a side view of the carriage 20 (described later) as seen from the direction of the arrow S in the figure.

  The ink jet printer 10 includes an ink cartridge 100 (yellow), an ink cartridge 200 (magenta), an ink cartridge 300 (cyan), and an ink cartridge 400 (black) as a liquid container in which inks of various colors are stored. It is mounted at 20 predetermined positions. The carriage 20 is fixed to the carriage belt 41, and moves in the horizontal direction of the drawing along the guide 21 fixed to the frame 27 as the carriage belt 41 is driven by the carriage motor 40. The printing paper 25 as a recording medium is transported and driven by a predetermined amount in the vertical direction of the drawing by a paper feed roller (not shown) driven by a driving motor 26 fixed to the frame 27. At this time, a predetermined amount of ink droplets 9 of each color corresponding to the print data is printed at a predetermined timing from a plurality of nozzles perforated on the side of the ejection head 30 facing the print paper 25 (the back side of the drawing). Is injected into. In this way, in the inkjet printer 10, a predetermined amount of ink droplets 9 of each color corresponding to the print data is ejected onto the entire printing paper 25, and an image is printed on the printing paper 25.

  Further, in the normal inkjet printer 10, the carriage 20 is moved to the position of the cleaning box 19 at a predetermined timing, and a predetermined cleaning treatment is performed. Specifically, air bubbles accumulated in the vicinity of the ink flow paths and nozzles formed in the ejection head 30 and thickened ink are ejected by ejecting the ink, or sucked out by evacuating the nozzle. The cleaning is done.

  The main control for such a series of operations is performed by the sub board 60 attached to the carriage 20 and the main board 50 attached to the frame 27. The main board 50 is connected to the sub board 60 by the flexible board 45.

  The main board 50 temporarily stores a CPU 51 for controlling various operations of the ink jet printer 10, a ROM 52 storing a program related to these operations, and data necessary for the operation, as shown in the upper blowing portion in the drawing. Interface (I / F) for exchanging data between the RAM 53 for recording and reading data and the sub-board 60 and exchanging information with an external device such as a user's personal computer (PC) 55. Data such as a processing routine program for detecting an injection state to be described later and a correspondence table are recorded in the ROM 52. The RAM 53 has a data buffer area, and print data output from the PC via the I / F 55 is recorded in this area.

  On the other hand, the sub board 60 is formed with a logic circuit for executing a predetermined operation such as data exchange with the main board 50. Accordingly, the CPU 51 reads out the program of each processing operation recorded in the ROM 52 and sends / receives various signal data to / from the sub board 60, whereby the CPU 51 executes a predetermined operation for the inkjet printer 10.

  Each of the ink cartridges 100 to 400 is attached with a circuit board 150 on which an IC chip on which individual information about the ink cartridge (for example, the date of manufacture of the ink cartridge and the color and composition of the stored ink) is recorded is mounted. . The circuit board 150 is provided with connection means (not shown) between the circuit board 150 and the sub board 60 so that individual information can be exchanged with the sub board 60. The CPU 51 performs processing such as recording and reading individual information on the IC chip via the sub-board 60. Therefore, the ink cartridge is specified by the individual information recorded on the IC chip.

  Each ink cartridge 100 to 400 can be attached to and detached from the carriage 20 by an attaching / detaching means 130 formed integrally with the ink cartridge and having a structure to be described later, as shown in the lower blowing portion in the drawing. Insertion is fixed in the state. Each of the ink cartridges 100 to 400 is provided with an ink supply port 107, and the ink supplied from the supply port 107 corresponds to each ink cartridge formed in the ejection head 30 according to an ink flow path (not shown). It is comprised so that it may flow to the nozzle corresponding to.

  Each nozzle formed is provided with a pressure generating mechanism for each nozzle, and is configured to generate pressure on the ink in the ejecting head and eject a predetermined amount of ink from the nozzle as ink droplets. The pressure generation mechanism will be described with reference to FIG. Of course, all the pressure generating mechanisms have the same structure.

  FIG. 2A is a structural diagram schematically showing a pressure generating mechanism formed in the ejection head 30. As shown in the figure, the pressure generating mechanism uses the piezoelectric element 2 as a driving body (actuator). When the voltage waveform shown in FIG. 2B is applied between the Com electrode and GND at both ends of the piezoelectric element 2, the piezoelectric element 2 contracts or expands due to electrostriction and is formed in the middle of the ink flow path. The ink existing in the pressurized chamber 8 is pressurized. As a result, the pressurized ink is ejected as ink droplets 9 from the nozzles 5 provided on the bottom surface member 4 of the ejection head 30.

  Next, ink ejection by the pressure generating mechanism will be specifically described based on the voltage waveform shown in FIG. FIG. 2B shows a voltage waveform applied to the piezoelectric element in this embodiment. First, the voltage V1 is applied to the Com electrode to contract the piezoelectric element 2 by a predetermined amount. This state ends before the start of printing, that is, this state becomes a reference position for the operation of the piezoelectric element 2 at the time of ink ejection. Next, the applied voltage is increased from V1 to V2, and the piezoelectric element 2 is further contracted. At this time, due to the meniscus (liquid level) formed in the nozzle 5, air does not enter from the nozzle 5, and ink supplied through the ink flow path from the ink cartridge is drawn into the pressurizing chamber 8. Next, the applied voltage is lowered from V2 to V3. Then, since the piezoelectric element 2 expands, the member 3 is pushed down in the direction of arrow F (downward in the drawing) by the expansion deformation, and the ink drawn into the pressurizing chamber 8 is pressurized. As a result, ink is ejected from the nozzle 5 as ink droplets 9. Thereafter, the voltage V1 is applied again to the piezoelectric element 2 to become the reference position and prepare for the next injection.

  In this way, the voltage waveform shown in FIG. 2B is applied to the piezoelectric element 2, so that the ejection is performed once, and the ink droplet is ejected once from the nozzle 5. Therefore, by applying the voltage waveform shown in FIG. 2B to each piezoelectric element 2 a plurality of times, ink droplets are ejected a plurality of times, and a predetermined amount of ink droplets are ejected from the nozzle 5 onto the printing paper 25. Thus, an image corresponding to each print data is printed. The operation of ejecting a predetermined amount of ink droplets for printing an image corresponds to the “ejection operation” described in the claims.

  Next, the specific structure of the ink cartridges 100 to 400 used in the ejection state detection apparatus according to this embodiment will be described with reference to FIG. FIG. 3 is a cross-sectional view of the ink cartridge 100 as viewed from the side, and is a schematic diagram schematically showing the overall configuration. Since the other ink cartridges 200, 300, and 400 all have the same structure as the ink cartridge 100, description thereof is omitted.

  As shown in FIG. 3, the ink cartridge 100 includes a resin ink container body 101 in which an ink storage portion 105 for storing ink is formed, and an attaching / detaching unit 130 provided integrally with the ink container body 101. And a supply port 107, a circuit board 150, two electrodes 110, and an electrode 120.

  The supply port 107 has a substantially pipe shape with an opening formed in the center portion, and functions as an ink supply port that supplies ink to the ejection head 30. That is, when the ink cartridge 100 is mounted on the carriage 20, the supply needle 70 provided on the carriage 20 side is inserted into the opening. Then, the ink stored in the ink storage unit 105 flows out to the supply needle 70 and the ink is supplied to the ejection head 30. When the ink cartridge 100 is not attached to the carriage 20, the opening of the supply port 107 is in a sealed state in which ink does not flow out, and the ink cartridge 100 is attached to the carriage 20 and the supply needle 70 is inserted. A valve mechanism that is in an open state when in use is configured as necessary.

  The attaching / detaching means 130 has a substantially hook shape as shown in the figure, and is formed so as to be bent in a state indicated by a two-dot chain line (reference numeral 130a) when the ink cartridge 100 is pushed downward in the drawing. Accordingly, the ink cartridge 100 is mounted by being pushed into the carriage 20 from above in the drawing. After the mounting, the groove 20b of the carriage 20 and the protrusion 130b are engaged so that the carriage 20 is fixed so as not to be pulled out upward in the drawing. Of course, when the ink cartridge 100 is removed from the carriage 20, the attaching / detaching means 130 may be bent in a state indicated by a two-dot chain line (reference numeral 130a) and then pulled upward in the drawing. Thus, the ink cartridge 100 is configured to be detachable from the carriage 20, that is, the ink jet printer 10. The attaching / detaching means in the present embodiment is an example, and other structures (for example, screwing) may be used as long as the attaching / detaching means can be attached / detached.

  Now, in order to use the ink cartridge 100 configured as described above as a battery of a volta, the two electrodes 110 and 120 are connected to the bottom of the ink container body 101 so as to come into contact with the ink stored in the ink storage unit 105. The end portion is fixed to (lower side of the drawing) and inserted into the ink containing portion 105. The electrode 110 and the electrode 120 are configured to be guided to predetermined terminals (not shown) provided on the circuit board 150 by the connecting member 111 and the connecting member 121, respectively.

  In this embodiment, the electrode 110 is a copper plate, and the electrode 120 is a zinc plate. Here, the ink stored in the ink storage unit 105 has different pH values indicating acidity and alkalinity depending on the composition of the ink, as disclosed in Patent Document 1 described above. As a function is different. Therefore, the magnitude of the electromotive force generated between the electrode 110 and the electrode 120 varies depending on the ink composition, that is, the type of ink.

  The electrode 110 and the electrode 120 are determined to be positive or negative depending on the magnitude of the ionization tendency. In this embodiment, the electrode 120 formed of a zinc plate having a large ionization tendency with respect to the copper plate becomes a negative pole. Of course, the electrode 110 and the electrode 120 inserted into the ink cartridge 100 may not be a copper plate and a zinc plate, but may be a magnesium plate, an aluminum plate, or the like. In short, any material can be used as the electrode as long as it is a conductive material that generates an electromotive force between the electrode 110 and the electrode 120 when melted in ink. Needless to say, the shape of the electrode and the state of insertion in the ink containing portion 105 are not limited to those shown in FIG.

  Now, when the two electrodes formed of materials having different ionization tendency come into contact with the ink stored in the ink storage portion 105 of the ink cartridge 100, the electrode 110 is interposed between the two electrodes as shown in FIG. An electromotive force is generated with the positive electrode and the electrode 120 as the negative electrode. Further, since the magnitude of the electromotive force generated is proportional to the amount of free electrons generated when the electrode material melts into the ink, the voltage corresponding to the area area where the ink is in contact with the two electrodes An electromotive force having a value is generated. Therefore, in the ink cartridge 100 shown in FIG. 3, the electromotive force generated varies depending on the remaining amount of ink stored in the ink storage unit 105.

  An example of how the electromotive force generated between the two electrodes provided in the ink cartridge 100 changes according to the amount of ink stored (that is, the remaining amount of ink) is shown in FIG.

  In FIG. 4, the vertical axis represents electromotive force (unit: volts), the horizontal axis represents ink remaining amount (unit: milliliter), and the ink remaining amount remaining in the ink containing portion 105 and generated between the two electrodes at that time. It is explanatory drawing which showed the correspondence with an electromotive force with the curve TK. As shown in the figure, the position where the ink remaining amount is Cf milliliters indicates that the ink storage unit 105 is fully filled with ink, and that the electromotive force at that time is VA volts. The position where the remaining amount of ink is Ce milliliters indicates an “empty” state in which there is no ink in contact with the electrode in the ink containing portion 105, and the electromotive force at that time is 0 volts.

  Now, when the ink stored in the ink cartridge 100 is decreased by ejecting ink droplets from the nozzles, the ink level PL (see FIG. 3) is lowered. For this reason, the contact area between the electrode 110 and the electrode 120 and the ink decreases, the area area of the portion where the electrode material melts decreases, and the volume of ink that can be melted also decreases. As a result, free electrons generated by melting the electrode material into the ink are reduced. In FIG. 4, when the ink remaining amount is Ca milliliter, the electromotive force is Va (<VA) volts, and the ink remaining amount is Cb milliliter. This shows that the electromotive force is Vb (<Va) volts. That is, when the electromotive force decreases from Va to Vb, it can be seen that the ink has decreased by “Ca-Cb”.

  Therefore, the ejection state detection device according to the present embodiment attempts to detect the ejection state of the ink droplets by measuring the magnitude of the electromotive force generated and correctly detecting the decrease amount of the ink stored in the ink cartridge. Is. Hereinafter, the injection state detection apparatus of the present embodiment will be described with reference to FIGS. 5 and 6. FIG. 5 is a functional block diagram of the injection state detection device of the present embodiment, and FIG. 6 is a flowchart of processing performed by the injection state detection device of the present embodiment.

  In the present embodiment, in FIG. 1, the CPU 51 operates as an injection state detection device by executing a processing program stored in the ROM 52 while using the RAM 53 as a working area. In particular, as shown in FIG. 5, it functions as a measurement unit 11, a liquid reduction amount calculation unit 12, a liquid ejection amount calculation unit 16, a determination unit 17, and a notification unit 18. Among these, the measurement unit 11 is formed on the circuit board 150, and the others are formed on the main board 50. Each unit mainly manages the following processing.

  The measuring unit 11 measures an electromotive force generated between two electrodes provided in the ink cartridge 100. The liquid reduction amount calculation unit 12 is recorded in the recording unit 13 and refers to the correspondence table 14 that defines the relationship between the electromotive force and the remaining amount of ink for each ink cartridge, and the ink in the ink cartridge 100 is measured from the measured electromotive force. Calculate the amount of decrease. The liquid ejection amount calculation unit 16 calculates the ejection amount of ink to be ejected in the ejection operation of the liquid ejection means 15 configured in the carriage 20. The determination unit 17 determines whether the ratio between the ink decrease amount calculated by the liquid decrease amount calculation unit 12 and the ink ejection amount calculated by the liquid ejection amount calculation unit 16 is a value in a predetermined range. Determine. The notification unit 18 notifies the injection state based on the determination result.

  In the present embodiment, the ROM 52 corresponds to the recording unit 13. The liquid ejecting means 15 is a means for ejecting ink contained in the ink cartridge 100 onto the printing paper 25, and includes a nozzle from the pressure generating mechanism described above and the supply port 107 formed before and after the pressure generating mechanism. The ink flow path up to 5 is included.

  Next, according to the flowchart of FIG. 6, the procedure of the process which the injection state detection apparatus in a present Example performs is demonstrated. This process is automatically started when the user of the ink jet printer 10 in FIG. 1 inputs a processing command by operating a predetermined operation button (not shown), or whenever printing is started. In this embodiment, the ink cartridge 100 is described as detecting the ejection state. Of course, it is a matter of course that the ejection state is similarly detected for all the ink cartridges 100 to 400.

  When this process is started, first, in step S1, the electromotive force generated between the two electrodes of the ink cartridge 100 is measured. In this embodiment, the CPU 51 converts a voltage value, which is analog data generated between two electrodes, into digital data by a measurement circuit (not shown) provided on the circuit board 150 provided in the ink cartridge 100. Measure by doing. By doing so, the distance of the conducting wire that electrically guides the electromotive force generated in the ink cartridge to the measurement circuit as analog data is shortened. Therefore, since the voltage drop of the electromotive force in the conducting wire is suppressed, it is possible to correctly measure the generated electromotive force.

  In the next step S2, a process for calculating the remaining amount of ink in the ink cartridge from the measured electromotive force and the correspondence table is performed. The correspondence table defines data indicating the amount of ink remaining in the ink storage unit 105 and data of electromotive force generated between two electrodes corresponding to the data, that is, a curve TK in FIG. It is a thing. The correspondence table is prepared for each of the ink cartridges 100 to 400 and is recorded in advance in a predetermined area of the ROM 52.

  Specifically, in step S2, the CPU 51 reads individual information from an IC chip provided on the circuit board 150 of the ink cartridge, and specifies the ink cartridge. Then, the remaining amount of ink is calculated by reading the correspondence table corresponding to the specified ink cartridge. In the present embodiment, it is assumed that the correspondence table defines the relationship between the electromotive force and the remaining ink amount by a mathematical expression. Accordingly, in step S2, the CPU 51 calculates the remaining amount of ink corresponding to the measured electromotive force using this mathematical formula.

  If the correspondence table defines an electromotive force value corresponding to a discontinuous ink remaining value such as a 5 milliliter interval, the CPU 51 has a value closest to the measured electromotive force. The electromotive force in the correspondence table may be searched, and the remaining ink level corresponding to the searched electromotive force may be read from the correspondence table. Alternatively, the remaining ink amount may be calculated from an electromotive force having values before and after the measured electromotive force by interpolation processing such as linear interpolation.

  Next, in step S3, the number of ejections performed by the liquid ejecting means after the electromotive force measurement process in step S1 is measured. The CPU 51 measures the number of injections by measuring the number of voltage waveforms applied to the piezoelectric element 2 in the pressure generation mechanism described above. In step S4, the ink ejection amount is calculated. The CPU 51 calculates the ink ejection amount by multiplying the number of ejections by the ink amount of one ink droplet ejected from the nozzle by the voltage waveform applied to the piezoelectric element 2. In this embodiment, it is assumed that the ink amount of one ink droplet is recorded in the ROM 52 in advance. In the image printing method in the inkjet printer 10, there are cases where the ink is ejected by applying voltage waveforms having different ink amounts of one ink droplet ejected from the nozzle to the piezoelectric element 2. In such a case, the number of applied voltage waveforms is measured for each voltage waveform having different ink amounts in one ink droplet, and the measured number is multiplied by the ink amount of one ink droplet. The amount should be calculated.

  Next, in step S5, it is determined whether or not the calculated injection amount is within a predetermined amount. If it is within the predetermined amount as a result of the determination (YES), the process returns to step S3 again, and the number of ejections is continuously measured to calculate the cumulative ejection amount of ink. In this embodiment, it is assumed that the predetermined amount is a value determined in advance as the smallest ink reduction amount that causes a certain difference in the electromotive force generated in the liquid container. In this way, it is possible to detect the ink ejection state with high accuracy and high frequency. Of course, the predetermined amount is not limited to this, and may be an ejection amount corresponding to a predetermined number of printed sheets such as one sheet of printing paper. In short, it is desirable to set the predetermined amount so that the ink ejection state can be detected accurately and with a favorable frequency.

  When the ink ejection amount exceeds the predetermined amount (step S5: NO), the electromotive force is measured in step S6. In this embodiment, as in step S1, the CPU 51 uses a measurement circuit (not shown) provided on the circuit board 150 provided in the ink cartridge 100 to generate a voltage value that is analog data generated between two electrodes. Is measured by converting to digital data.

  Next, in step S7, a process of calculating the remaining amount of ink in the ink cartridge from the measured electromotive force and the correspondence table is performed. Similar to the processing in step S2 described above, the CPU 51 calculates the remaining amount of ink corresponding to the measured electromotive force using a correspondence table in which the electromotive force and the remaining amount of ink are defined by mathematical expressions.

  In step S8, the amount of ink stored in the ink cartridge 100 is calculated. The CPU 51 calculates the ink decrease amount by subtracting the ink remaining amount calculated in Step S8 from the ink remaining amount calculated in Step S2.

  Next, in step S9, a process of calculating the ratio R between the ink ejection amount and the ink decrease amount is performed. In this embodiment, the CPU 51 calculates the ratio R by dividing the ink ejection amount calculated in step S4 by the ink decrease amount calculated in step S8. Here, in order to facilitate understanding of the processing in the next step S10 and subsequent steps, the “ratio R between the ink ejection amount and the ink reduction amount” calculated in step S9 will be supplementarily described with reference to FIG.

  FIG. 7 is an explanatory diagram showing the ratio R (= ink ejection amount / ink reduction amount) as a straight line, with the horizontal axis representing the ink reduction amount and the vertical axis representing the ink ejection amount. First, when the ink is ejected normally and the ink ejection amount is equal to the ink reduction amount, as shown by the point P1 in the figure, if the ink ejection amount is CA, the ink reduction amount is also CA. The ratio R is R = 1. However, the amount of one drop of ink used in the normal ejection amount calculation process does not always match the amount of one droplet of ink that is actually ejected. For example, regarding the electrostrictive property of the piezoelectric element described above, the ink ejection amount and the ink decrease amount as shown in the figure due to variations in electromechanical coupling coefficient indicating electrostriction performance, nozzle shape variation, ink composition variation, etc. Variation occurs between the two. As a result, when the amount of ink droplets that are actually ejected is larger than the ink ejection amount, the ink reduction amount increases, so the ratio R becomes smaller, for example, R = 0.9. On the other hand, when the amount of ink droplets that are actually ejected is small relative to the ink ejection amount, the amount of ink decrease is small, so the ratio R is large, for example, R = 1.1. Accordingly, in FIG. 7, the range of 0.9 ≦ R ≦ 1.1 is a range of ratios that can occur when ink is normally ejected. If the ratio R is within this range, the ink is It will be injected normally.

  Next, if the ink becomes clogged and the amount of one ink droplet actually ejected is considerably smaller than the amount of one ink droplet used in the normal ejection amount calculation process, As indicated by P2, the ink ejection amount is CA, whereas the ink decrease amount is CB which is considerably smaller than CA. At this time, the ratio R exhibits a large value with respect to a value indicating a state in which ink is normally ejected. From this, for example, if the ratio R when the ink reduction amount is CB in FIG. 7 is R = 1.5, the range of 1.1 <R ≦ 1.5 is likely to be clogged with ink. This is a range indicating that the fuel is being injected in a state.

  Next, when the ink is further clogged and finally clogged completely, as indicated by a point P3 in the figure, the ink ejection amount is CA, whereas the ink reduction amount is “0”. The ratio R is infinite. That is, as the ink clogging increases, the ratio R takes on a larger value. From this, for example, the range of the ratio R showing a value larger than the ratio R = 1.5 when the ink decrease amount is CB in FIG. 7 is a range showing a state where ink clogging is large. This is a range indicating a state that requires cleaning.

  Conversely, as indicated by a point P4 in the figure, the ink ejection amount is CA, whereas the ink decrease amount is CC that is considerably larger than CA, and the ratio R is R = 0.7. It is also conceivable that the ink exhibits a value smaller than the value R = 0.9 in the range where ink is normally ejected. This indicates that the ink is consumed in addition to the ejection of the ink from the nozzle, that is, indicates that the ink is leaking from the ink flow path. From this, the range in which the ratio R shows a value smaller than R = 0.9 indicates a state where ink is leaking.

  As described above with reference to FIG. 7, “the ratio R between the ink ejection amount and the ink reduction amount” is calculated, and the ink ejection state from the nozzles is detected by considering the value of the calculated ratio R. It becomes possible. In this embodiment, the CPU 51 calculates the ratio R by dividing the ink ejection amount calculated in step S4 by the ink decrease amount calculated in step S8. The ratio R may be calculated by dividing the calculated ink decrease amount by the ink ejection amount calculated in step S4. In this case, although explanation is omitted, it goes without saying that the relationship of the injection state with respect to the value of the ratio R is opposite to the relationship of the value of R with respect to the state shown in FIG.

  Returning to FIG. 6, the processing after step S10 will be described. In step S10, it is determined whether or not the calculated ratio R is within the first range. The first range is a range corresponding to the ratio 0.9 ≦ R ≦ 1.1 indicating the normal injection state described in FIG. This first range is set according to the performance of the liquid ejecting means formed in the ink jet printer, and is stored in the ROM 52 in advance. Therefore, the CPU 51 reads out the stored first range and performs a determination process by comparing with the calculated ratio R.

  As a result of the determination, if the ratio R is within the first range (YES), notification processing is performed in step S11 that the injection is normal. On the other hand, if the ratio R is not within the first range (NO), the process proceeds to step S12.

  In step S12, it is determined whether or not the calculated ratio R is within the second range. The second range is a range corresponding to the ratio 1.1 <R ≦ 1.5 indicating the clogged injection state described in FIG. Similarly to the first range, the second range is set according to the performance of the liquid ejecting means formed in the ink jet printer and stored in the ROM 52 in advance. Therefore, the CPU 51 reads out the stored second range and performs a determination process by comparing with the calculated ratio R.

  As a result of the determination, if the ratio R is within the second range (YES), a notification process is performed in step S13 to indicate that the injection is clogged. On the other hand, if the ratio R is not within the second range (NO), the process proceeds to step S14.

  In step S14, it is determined whether or not the calculated ratio R is greater than the second range. As a result of the determination, if the ratio R is larger than the second range (YES), since the injection is clogged as described with reference to FIG. 7, notification of the necessity of cleaning is performed in step S15. On the other hand, if the ratio R is not larger than the second range (NO), since the ink is leaking in the ink flow path as described with reference to FIG. 7, the liquid leakage is notified in step S16. . In this way, information corresponding to the calculated value of the ratio R is notified, and the injection state detection process in the present embodiment is terminated.

  In this embodiment, the notification process is performed by displaying a predetermined sentence on a liquid crystal display panel (not shown) provided in the inkjet printer 10 shown in FIG. Specifically, the CPU 51 selects and displays an appropriate sentence from sentences stored in advance in the ROM 52. For example, in the case of the process in step S11, a sentence “ink is ejected normally” is displayed. Further, in the case of the processing in step S15, the text “Ink is clogged. Please clean immediately” is displayed. By performing the notification process in this manner, for example, the user of the inkjet printer 10 can easily determine whether or not the ink contained in the ink cartridge mounted on the carriage is correctly ejected from the nozzle by the displayed text. Can be confirmed.

  As described above, according to the ejection state detection device according to the present embodiment, the ejection state of ink can be detected by using the electromotive force generated in the ink cartridge. Therefore, for example, even when the thickened ink suppresses the flow of ink in the ink flow path and the ink does not flow smoothly, the ink ejection state can be detected. Further, since no special detection element is used, it is not necessary to secure a space for arranging the detection element in the ejection head, and the ink flow path is restricted for detection by the detection element. That doesn't happen either. In addition, a circuit relating to detection by the detection element is not necessary, and cost increase is also suppressed. As a result, the present invention is an ejection state detection device suitable for an ink jet printer especially intended for downsizing and cost reduction.

  The embodiments of the present invention have been described with reference to the examples. However, the present invention is not limited to these examples, and can be implemented in various forms without departing from the spirit of the present invention. Of course. Hereinafter, a modification will be described.

(Modification)
In the above embodiment, the ejection state is detected when the ink ejection amount calculated in the ejection operation reaches a predetermined amount. However, the present invention is not limited to this. For example, for one print data, the ejection state may be detected for the ejection operation from the start to the end of printing. In this case, the frequency of detecting the ejection state may be reduced. However, since the ejection state is detected for one piece of print data, a process for detecting when the ink ejection amount reaches a predetermined amount (see FIG. 6, the process of step S5) becomes unnecessary, and the processing load related to the injection state detection is reduced.

  In the above embodiment, as described with reference to the flowchart of FIG. 6, when the ink ejection amount calculated in the ejection operation reaches a predetermined amount, the ejection state is detected and the ejection state detection process is terminated. However, when the printing is performed continuously thereafter, the ejection state detection process may be started again after the ejection state is detected. In this way, even if the ink ejection state changes during printing, the ejection state is repeatedly detected, so the probability that the changed ejection state can be detected increases.

  In the above-described embodiment, as described with reference to the flowchart of FIG. 6, the ratio R between the ink ejection amount and the ink reduction amount is determined by comparing the two ranges of the first range and the second range. However, the comparison determination may be performed by setting more ranges. In this way, as can be understood from the description with reference to FIG. 7, the ink ejection state can be further divided and detected. As a result, since a treatment such as cleaning can be performed according to the subdivided injection state, there is a high possibility that an optimum treatment according to the injection state can be performed.

  Alternatively, the ratio R between the ink ejection amount and the ink decrease amount may be compared and determined for only one range instead of a plurality of ranges. For example, in a state other than the normal ink ejection state, when the cleaning process is always performed so that a stable image can be reliably printed, it is only necessary to determine the first range described above. . Thus, since the comparison determination process is performed for one ratio range corresponding to the injection state to be detected, a desired injection state can be detected and a processing load related to the detection of the injection state can be reduced.

  In the above embodiment, the measurement unit 11 is provided on the circuit board 150 as shown in FIG. 5, but may be provided on the main board 50. Alternatively, it may be provided on the sub-board 60. In the above embodiment, the measurement unit is provided on the circuit board 150 in order to suppress the voltage drop of the electromotive force generated in the ink cartridge and correctly measure the generated electromotive force. If the electromotive force can be measured correctly by reducing the influence of the voltage drop, it is not necessary to provide the circuit board 150 in particular.

  In the above embodiment, as described in the flowchart of FIG. 6, the notification unit 18 notifies the determination result by displaying a predetermined sentence on the liquid crystal display panel. However, the present invention is not limited to this. Of course. For example, it may be notified by sound. In the case where a sounding body is provided in the inkjet printer 10, it is possible to notify the ejection state by changing the sound output method (frequency, volume, sounding pattern, etc.).

  Or the notification part 18 is good also as notifying by outputting the trigger signal regarding operation | movement of the inkjet printer 10. FIG. For example, a trigger signal for stopping the printing operation is output in the process of step S15. In this case, when the ink is not ejected correctly due to ink clogging, the printing operation can be stopped, and therefore it is possible to suppress useless printing in which an image is not stably formed.

  In the above embodiment, the correspondence table is recorded in the ROM 52 in advance. However, the correspondence table is sent from the PC together with print data and other data (for example, version upgrade data for the printer driver of the inkjet printer) sent from the PC. The data may be stored in the RAM 53. In this way, the correspondence table can be updated to the latest data each time. In this case, the RAM 53 corresponds to the recording unit 13.

  In the above embodiment, the ink for forming an image on the printing paper is exemplified as the liquid. However, the present invention is not limited to this. For example, it may be a recording liquid or a functional liquid for forming an image on a glass substrate or a resin substrate and forming a constituent member of a liquid crystal panel or an organic EL panel.

  In the above embodiment, the liquid ejecting apparatus has been described as an ink jet printer. However, the present invention is not limited to this. Any device can be used as long as it can eject recording liquid and functional liquid, including the ink described above.

  In the above embodiment, the ink cartridge is described as being an ink cartridge that is detachably attached to the inkjet printer 10, but it is needless to say that the present invention is not limited to this. For example, it may be a tank type ink cartridge that supplies ink from an ink container through a supply pipe.

  In the above embodiment, the method of using the piezoelectric element 2 as a driving body has been described as a method of ejecting ink droplets. However, a so-called thermal method of ejecting ink droplets using a heating element as a driving body may be used. .

  The present invention can also be implemented as an injection state detection method. Since the injection state detection method conforms to the description of the processing in the embodiment and the modification of the injection state detection device described above, the description thereof is omitted.

1 is a schematic structural diagram of an ink jet printer incorporating an ejection state detection device of an embodiment. (A) is a structural diagram of a pressure generating mechanism formed in the ejection head, (b) is an explanatory diagram of a voltage waveform for operating the pressure generating mechanism. FIG. 3 is a cross-sectional view of the ink cartridge as viewed from the side, and a schematic diagram illustrating the overall configuration thereof. FIG. 4 is an explanatory diagram for explaining a curve indicating a correspondence relationship between an electromotive force and an ink remaining amount. The functional block diagram of the injection state detection apparatus of an Example. The processing flowchart which the injection state detection apparatus of an Example performs. Explanatory drawing for demonstrating the ratio R of the ink reduction amount and the ink ejection amount.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 2 ... Piezoelectric element, 3 ... Member, 4 ... Bottom member, 5 ... Nozzle, 8 ... Pressurizing chamber, 9 ... Ink drop, 10 ... Inkjet printer, 11 ... Measurement part, 12 ... Liquid reduction amount calculation part, 13 ... Recording Means, 14 ... Correspondence table, 15 ... Liquid ejecting means, 16 ... Liquid ejecting amount calculation section, 17 ... Determination section, 18 ... Notification section, 19 ... Cleaning box, 20 ... Carriage, 20b ... Groove section, 21 ... Guide, 25 ... Printing paper, 26 ... drive motor, 27 ... frame, 30 ... jet head, 40 ... carriage motor, 41 ... carriage belt, 45 ... flexible substrate, 50 ... main substrate, 51 ... CPU, 52 ... ROM, 53 ... RAM, 55 ... I / F, 60 ... Sub-board, 70 ... Supply needle, 100 ... Ink cartridge, 101 ... Ink container body, 105 ... Ink container, 107 ... Supply port, 110 ... Electrode, 111 ... connection member, 120 ... electrode, 130, 130a ... connecting unit, 130b ... projections, 150 ... circuit board, 200, 300, 400 ... ink cartridge.

Claims (7)

An ejection state detection device that detects an ejection state of the liquid with respect to a liquid ejection unit that ejects the liquid stored in the liquid storage container by an ejection operation,
The liquid storage container has two electrodes, and a measuring unit that measures an electromotive force generated between the two electrodes when the liquid is stored in the liquid storage container before and after the ejection operation;
A liquid reduction amount calculation unit for calculating a reduction amount of the liquid stored in the liquid storage container using the measured electromotive force;
A liquid ejection amount calculation unit that calculates an ejection amount of the liquid to be ejected by the ejection operation;
A determination unit that determines whether a ratio between the calculated liquid decrease amount and the calculated liquid ejection amount is a value in a predetermined range;
Based on a determination result of the determination unit, a notification unit that notifies the liquid ejection unit of the liquid ejection state;
An injection state detection device comprising: The injection state detection device according to claim 1,
The said measurement part measures the said electromotive force before and behind the said injection operation about the said injection operation in which the injection quantity of the said liquid becomes a predetermined value, The injection state detection apparatus characterized by the above-mentioned. The injection state detection device according to claim 1 or 2,
The determination unit includes a plurality of the predetermined ranges, and a ratio between the calculated liquid reduction amount and the calculated liquid ejection amount is a value of the predetermined ranges. Or not for each range,
The notifying unit notifies the jetting state of the liquid according to the plurality of predetermined ranges for the liquid ejecting unit based on a determination result of the determining unit. The injection state detection device according to any one of claims 1 to 3,
A recording unit in which a correspondence table defining a relationship between the amount of liquid stored in the liquid storage container and electromotive force is recorded;
The liquid decrease amount calculation unit calculates the decrease amount of the liquid stored in the liquid storage container using the recorded correspondence table. The injection state detection device according to any one of claims 1 to 4,
The measurement unit is provided in the liquid storage container. An injection state detection device according to any one of claims 1 to 5,
The said two electrodes are formed with the material from which an ionization tendency differs, The injection state detection apparatus characterized by the above-mentioned. An ejection state detection method for detecting an ejection state of the liquid with respect to a liquid ejection unit that ejects the liquid stored in the liquid storage container by an ejection operation,
The liquid container has two electrodes, and a measuring step of measuring an electromotive force generated between the two electrodes by storing liquid in the liquid container before and after the ejection operation;
A liquid reduction amount calculating step of calculating a reduction amount of the liquid stored in the liquid storage container using the measured electromotive force;
A liquid ejection amount calculating step for calculating an ejection amount of the liquid to be ejected by the ejection operation;
A determination step of determining whether a ratio between the calculated liquid decrease amount and the calculated liquid ejection amount is a value within a predetermined range;
Based on the determination result in the determination step, a notification step of notifying the liquid ejection state of the liquid ejection means;
An injection state detection method comprising:

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