JP7058963B2 - Inkjet recording device and its judgment method - Google Patents

Description

The present invention relates to a recording device in which an ink tank and a recording head are connected by a supply tube and a detection method thereof.

Patent Document 1 discloses an inkjet recording apparatus in which an ink tank and a recording head are connected by an ink supply tube and an on-off valve is provided in the middle of the ink supply tube. The recording head is filled with ink by a suction operation in which the ink supply tube and the inside of the recording head are depressurized by a suction means with the on-off valve closed, and the on-off valve is released when the pressure reaches a predetermined value. By performing this suction operation a predetermined number of times, the flow path from the ink tank to the recording head is filled with ink.

Further, after the ink filling operation is completed, the ink is ejected from the recording head, and the ink is actually filled up to the recording head by detecting whether or not the ink is ejected by the non-ejection detecting means. There is a technique for confirming whether or not it is a conventional technique. For example, when there is a poor connection between the ink tank and the recording device main body, the ink is not ejected from the recording head, so that the non-ejection detecting means determines that the recording head is in the non-ejection state.

Japanese Unexamined Patent Publication No. 2002-248792

In the configuration of Patent Document 1, since the suction operation described above is repeated a predetermined number of times during the ink filling operation and then non-ejection detection is performed, it takes time to detect a connection failure between the ink tank and the recording device. It sometimes took.

In view of the above problems, the present invention can shorten the time for detecting the presence or absence of a defect between the ink tank and the suction means in the configuration in which the ink tank and the recording head are connected and the ink is filled by the suction means. The purpose is to provide the device.

In order to achieve the above object, the present invention has a recording head having an ejection port surface provided with a plurality of ejection ports for ejecting ink, an ink tank for accommodating ink supplied to the recording head, and the ejection port. A cap that can be switched between a covered state that covers the surface and an exposed state that is exposed, and a suction means that is connected to the cap are provided, and when the cap is in the covered state, suction is performed by the suction means. This is a recording device that performs an ink filling operation for filling ink from the ink tank to the recording head, and is between the ink tank and the suction means measured by the pressure measuring means during the ink filling operation. It is further provided with a detecting means for detecting the presence or absence of a defect in the ink flow path based on the pressure of the provided ink flow path.

INDUSTRIAL APPLICABILITY According to the present invention, in a configuration in which an ink tank and a recording head are connected and ink is filled by a suction means, a recording device capable of shortening the time for determining the presence or absence of a defect between the ink tank and the suction means is provided. Will be done.

It is a perspective view which shows the inkjet recording apparatus which concerns on 1st Embodiment. It is a conceptual diagram which shows the ink flow path for one color of the inkjet recording apparatus which concerns on 1st Embodiment. It is a block diagram which shows the internal structure of the inkjet recording apparatus which concerns on 1st Embodiment. It is a flowchart which shows the valve closing suction operation of the inkjet recording apparatus which concerns on 1st Embodiment. It is a figure which shows the 1st valve closing suction operation at the time of initial installation of the inkjet recording apparatus which concerns on 1st Embodiment. It is a figure which shows the state which opened the opening-off valve in the valve closing suction operation of the inkjet recording apparatus which concerns on 1st Embodiment. It is a figure which shows the second valve closing suction operation at the time of initial installation of the inkjet recording apparatus which concerns on 1st Embodiment. It is a figure which shows the 3rd valve closing suction operation at the time of initial installation of the inkjet recording apparatus which concerns on 1st Embodiment. It is a figure which shows the 4th valve closing suction operation at the time of initial installation of the inkjet recording apparatus which concerns on 1st Embodiment. It is a flowchart which shows the initial filling operation of the inkjet recording apparatus which concerns on 1st Embodiment. It is a figure which shows the 1st valve closing suction operation at the time of initial installation of the inkjet recording apparatus which concerns on 2nd Embodiment. It is a flowchart which shows the initial filling operation of the inkjet recording apparatus which concerns on 2nd Embodiment.

An embodiment of the inkjet recording apparatus according to the present invention will be described. However, the components described in the embodiments are merely examples, and are not intended to limit the scope of the present invention. In the present specification, a serial type inkjet recording device is used as an example in which a head that ejects ink to a recording medium that is intermittently conveyed is reciprocated in a direction intersecting the conveying direction of the recording medium to perform recording. explain. However, the present invention is not limited to the serial type inkjet recording device, but can also be applied to a line type inkjet recording device that continuously prints using a long print head. In the present specification, "ink" is used as a general term for liquids such as recording liquids. Further, in the present specification, the term "record" includes not only a record for a two-dimensional object but also a record for a three-dimensional object. As used herein, the term "recording medium" is used as a general term for recording media such as paper, cloth, plastic film, metal plate, glass, ceramics, wood, and leather, which discharge liquid. Further, the recording medium is not limited to roll-shaped continuous paper, but also includes cut paper. The inkjet recording device can be applied not only to a PC printer but also to a multifunction printer having a copy function, a facsimile function, and the like.

[First Embodiment]
FIG. 1 is a schematic perspective view showing the internal structure of an inkjet recording device (hereinafter referred to as a recording device) 50. The recording device 50 is supported and fixed to the upper portions of two legs 55 provided so as to face each other. Inside the recording device 50, a carriage 60 that reciprocates in the X direction by the belt transmission means 62 is provided. The carriage 60 is equipped with a recording head 1 that performs a recording operation of ejecting ink to a recording medium to record an image. The recording head 1 ejects ink droplets from each ejection port based on the recording data sent from the host computer or the like, and records an image on a recording medium.

A roll holder unit 52 for holding a recording medium is provided on the front surface of the recording device 50. The recording medium of this embodiment is a roll-shaped continuous paper. The recording medium is fed from the roll holder unit 52 to the inside of the recording device 50 to the recording position where the recording operation by the recording head 1 is performed. The recording medium on which the image is recorded is conveyed in the Y direction which intersects the X direction. In this embodiment, the X direction and the Y direction are orthogonal to each other. When an image for one band is recorded by the recording operation of the recording head 1, the recording medium is conveyed in the Y direction by a predetermined transfer amount by the rotation of the transfer roller 51 (intermittent transfer operation). By repeating the recording operation for one band and the intermittent transfer operation, an image is recorded on the entire recording medium. When recording on the recording medium is completed, the recording medium is cut by a cutter (not shown), and the cut recording medium is loaded on a stacker 53 provided on the front surface of the recording device 50.

An ink supply unit 63 is further provided on the front side of the recording device 50. The ink supply unit 63 has an ink tank 5 for accommodating ink for each color such as black, cyan (first ink), magenta (second ink), and yellow, and each ink tank 5 is used in the recording device 50. On the other hand, it is provided so that it can be attached and detached. A supply tube (ink supply path) 2 made of a flexible member or the like is connected to the ink tank 5, and the ink tank 5 and the recording head 1 are connected by the supply tube 2. The surface of the recording head 1 facing the recording medium is a discharge port surface 20 provided with a plurality of discharge ports, and the discharge port surface 20 is a row of discharge ports provided with a plurality of discharge ports along the Y direction for each color. Prepare for. A plurality of supply tubes 2 provided for each color of ink are connected to each discharge port row and bundled by a tube guide 61.

The recovery unit 70 is provided within the scanning range of the carriage 60 in the X direction and outside the transport area of the recording medium. The recovery unit 70 is a valve for sucking ink or air from a plurality of ejection ports provided on the ejection port surface 20 to perform a cleaning operation or filling ink from the ink tank 5 to the recording head 1 as needed. Performs a closing suction operation (described later).

An operation panel 54 is provided above the ink supply unit 63 on the front side of the recording device 50. When the user operates the operation panel 54, a command to the recording device 50 is input. The operation panel 54 also includes, for example, a touch panel type having a function of a display panel for issuing a warning to the user when the ink tank 5 needs to be replaced.

FIG. 2 is a conceptual diagram showing an ink flow path for one color from the ink tank 5 to the recording head 1. An atmospheric communication chamber 6 is provided vertically below the ink tank 5, and a first hollow tube 9 extending vertically upward is provided in the atmospheric communication chamber 6. Further, the ink tank 5 has a first joint portion 90 and a second joint portion 80 at the bottom thereof. By inserting the first hollow tube 9 into the first joint portion 90, the ink tank 5 and the atmospheric communication chamber 6 are connected. Since the atmospheric communication chamber 6 has an atmospheric communication passage 7 that communicates with the outside atmosphere, the ink tank 5 and the atmosphere communicate with each other through the atmospheric communication passage 7.

A second hollow tube 8 connected to the supply tube 2 and extending vertically upward is inserted into the second joint portion 80 of the ink tank 5, whereby the ink tank 5 and the recording head 1 are connected via the supply tube 2. Ink. The supply tube 2 is further provided with an on-off valve 3 that can switch between an open state in which the supply tube 2 is opened and a closed state in which the supply tube 2 is closed, and the on-off valve 3 is driven by an on-off valve motor 35 that is a drive source. Hereinafter, the inside of the recording head 1 and the supply tube 2 are also referred to as ink supply paths.

The recording head 1 has a discharge port surface 20 having a plurality of discharge ports provided at the bottom thereof, and has a filter 21 inside for capturing impurities mixed in the ink. The discharge port surface 20 is arranged above the lower end of the first hollow pipe 9 communicating with the atmosphere in the vertical direction. As a result, when the ink is filled from the ink tank 5 to the recording head 1, the negative pressure is maintained at each ejection port and the meniscus is maintained. During the recording operation, when the ink in the recording head 1 is consumed by ejecting ink from each ejection port, ink is supplied from the ink tank 5 to each ejection port via the supply tube 2 at any time. .. Such an ink supply method is also called a head difference method. In this embodiment, the height difference between the discharge port surface 20 and the lower end portion of the first hollow pipe 9, that is, the so-called head difference H is about 80 mm.

Next, the configuration of the recovery unit 70 will be described. The recovery unit 70 has a cap 22 capable of sealing the discharge port surface 20 and a suction pump (suction means) 23 connected to the cap 22. The cap 22 can be switched between a covered state in which the discharge port surface 20 is sealed and an exposed state in which the discharge port surface 20 is exposed. An in-cap absorber 29 is provided in the cap 22, and the suction pump 23 creates a negative pressure in the cap 22 via the in-cap absorber 29. By providing the absorber 29 in the cap, it is possible to uniformly reduce the pressure in the cap 22 at the time of suction by the suction pump 23. The suction pump 23 is a tube pump, and the average flow rate is proportional to the rotation speed of the tube pump. In the present embodiment, the suction pump motor 28 is controlled so that the flow rate of the suction pump 23 becomes substantially constant.

The cap 22 is further provided with an atmospheric release valve 30, and the atmospheric release valve 30 switches between communication and non-communication between the cap 22 and the atmosphere. The opening and closing of the atmosphere release valve 30 is performed by the atmosphere valve motor 31. In the present embodiment, a pressure sensor (pressure measuring means) 25 is further arranged between the cap 22 and the suction pump 23. The pressure sensor 25 converts the pressure of a gas or liquid into an electric signal and outputs it. For example, there are a strain gauge type for measuring strain and a capacitance type for measuring a change in capacitance. The ink supply using the pressure sensor 25 will be described later.

For example, when performing a preliminary ink ejection operation (preliminary ejection operation) for suppressing ejection defects of the recording head 1 as a recovery operation for the recording head 1, ink is ejected to the absorber 29 in the cap. In this way, the ink received by the cap 22 by the recovery operation is sucked by the suction pump 23 and stored in the maintenance cartridge 24. The CPU 11 (see FIG. 3), which will be described later, calculates the amount of ink collected by the maintenance cartridge 24, and when the calculated ink amount reaches the threshold value, informs the user to replace the maintenance cartridge 24 with a new one. The amount of ink collected by the maintenance cartridge 24 is calculated by estimating the amount of ink that has flowed into the maintenance cartridge 24 by the CPU 11 and sequentially adding the amount of ink to the capacity memory 26.

FIG. 3 is a block diagram showing an internal configuration of the recording device 50. The CPU (control means, determination means) 11 is an arithmetic processing unit for controlling the entire recording device 50. In the present embodiment, the CPU 11 is also connected to a timer circuit, and the elapsed time can be measured. The RAM 14 is a storage device capable of holding information temporarily used when operating the control software. The ROM 13 is a storage device having built-in control software and capable of reading only. The user interface (I / F) 12 includes an operation panel 54 for displaying keys and information operated by the user, and operates as a data transmission / reception communication port for connecting the recording device 50 and the host computer. The input / output I / O 15 controls the input / output of the head discharge drive unit 27 for discharging ink to the recording head 1, the suction pump motor 28, the atmosphere valve motor 31, the on-off valve motor 35, the pressure sensor 25, and the capacity memory 26.

The operation of filling ink from the ink tank 5 to the recording head 1 at the time of initial installation of the recording device 50 is referred to as an ink filling operation. When performing the ink filling operation in the present embodiment, the valve closing suction operation described with reference to the flowchart of FIG. 4 is repeatedly executed.

First, in step S401, the CPU 11 covers the cap 22, seals the discharge port surface 20, and closes the on-off valve 3. As a result, a closed space is formed in the section from the middle of the supply tube 2 to the cap 22. In step S402, the CPU 11 drives the suction pump motor 28, and the suction pump 23 sucks the inside of the recording head 1 and the inside of the supply tube 2 via the cap 22. As a result, ink and air are extracted from the recording head 1 and the supply tube 2 to reduce the pressure.

In step S403, the CPU 11 determines whether or not a predetermined time (55 seconds in this embodiment) has elapsed from the start of suction of the suction pump 23. After sucking for a predetermined time, the CPU 11 stops the suction pump motor 28 in step S404 to stop the suction by the suction pump 23, and the on-off valve 3 is opened in step S405. As a result, the ink in the ink tank 5 is supplied to the inside of the recording head 1 and the inside of the supply tube 2 located in the depressurized closed space in about 1 to 2 seconds by releasing the negative pressure. The series of flows shown in FIG. 4 is referred to as a valve closing suction operation.

Since the amount of ink that can be filled by the valve closing suction operation per time is limited, it is necessary to repeatedly execute the valve closing suction operation when the supply tube 2 having a large volume is used as in the present embodiment. After filling the recording head 1 with ink, the CPU 11 controls the atmosphere valve motor 31 to open the atmosphere release valve 30 and drives the suction pump motor 28 in order to discharge the ink received by the absorber 29 in the cap. The empty suction operation is executed by the suction pump 23.

It should be noted that the valve closing suction operation is performed regularly for the purpose of forcibly discharging air bubbles from the discharge port when air bubbles generated from the discharge port are accumulated in the recording head 1 and a discharge failure occurs, even when the air bubbles are not initially installed. Will be executed. Furthermore, when the recording device 50 that has started to be used is moved to another place, that is, the ink is discharged from the ink supply path for so-called secondary transportation, the ink is refilled at the time of re-installation after the movement. It is executed for the purpose.

FIG. 5A shows a state in which the on-off valve 3 is closed and the inside of the recording head 1 and the inside of the supply tube 2 are depressurized in order to perform the first valve closing suction operation at the time of initial installation of the recording device 50. show. That is, FIG. 5 corresponds to step S402 in the flowchart of FIG. Since it is the initial installation, ink is not supplied to the supply tube 2 and the recording head 1. FIG. 5B shows a change in pressure with time of operation of the suction pump 23 in FIG. 5A, where the horizontal axis is time (seconds) and the vertical axis is negative pressure value (kPa). From FIG. 5B, it can be seen that the negative pressure increases as the suction pump 23 is operated.

FIG. 6A shows a state in which the on-off valve 3 is opened after the suction operation by the suction pump 23 is performed for a predetermined time. That is, FIG. 6 corresponds to step S405 in the flowchart of FIG. 4, and supplies a predetermined amount of ink from the ink tank 5 to the supply tube 2 by releasing the negative pressure in the ink supply path. Ink is filled halfway in the supply tube 2 by one valve closing suction operation shown in FIGS. 5 and 6. FIG. 6B shows the measurement result of the pressure in FIG. 6A. By opening the on-off valve 3 about 55 seconds after the start of driving by the suction pump 23, the pressure (negative pressure) is released and the negative pressure value drops. The above is the state of ink supply and pressure change in one valve closing suction operation.

Subsequently, with reference to FIGS. 5 and 7 to 9, a state in which the valve closing suction operation is repeatedly performed to fill the recording head 1 with ink is shown. As described above, FIG. 5A shows a state in which the on-off valve 3 is closed and the inside of the recording head 1 and the supply tube 2 is depressurized in the first valve closing suction operation, and is shown in FIG. 5 (b). ) Indicates the pressure measurement result at that time. Before the first valve closing suction operation is started, the ink supply path is filled with air because the ink is not supplied to the recording head 1 and the supply tube 2. The compressibility of air is higher than that of liquid, and the volume tends to expand or contract in response to changes in pressure. Therefore, when the ink supply path is filled with air as shown in FIG. 5A, the amount of pressure change per unit time (gradient of the graph in FIG. 5B) is small.

In FIG. 5B, the amount of pressure change from 0 to 5 seconds after the start of suction by the suction pump 23 is different from the amount of pressure change thereafter. This is because the negative pressure value becomes about 20 kPa due to the discharge port of the recording head 1 and the fluid resistance of the filter 21. That is, for 5 seconds until the negative pressure value (pressure value) becomes about 20 kPa or more, substantially the same pressure change is measured regardless of the amount of air in the recording head 1 or the supply tube 2.

The amount of subsequent pressure change in FIG. 5B is about 9 kPa in 10 seconds from 5 seconds to 15 seconds after the start of suction, about 8 kPa in 10 seconds from 15 seconds to 25 seconds, and about 10 seconds from 25 seconds to 35 seconds. It is 6 kPa. In the present embodiment, the volume of the supply tube 2 is about 40 ml, the volume of the recording head 1 is about 5 ml, and the volume from the cap 22 to the suction pump 23 is about 5 ml. At the time of initial installation, a total volume of about 50 ml from the supply tube 2, the recording head 1, the cap 22 to the suction pump 23 is almost entirely filled with air. Therefore, the flow rate of the suction pump 23 is about 0.5 ml / s when calculated from the relationship of PV = constant from the amount of pressure change per unit time shown in FIG. 5 (b).

FIG. 7A shows a state in which the on-off valve 3 is closed and the pressure inside the recording head 1 and the supply tube 2 is depressurized in the second valve closing suction operation, and FIG. 7B shows the pressure at that time. The measurement result is shown. Since the ink is supplied to the middle of the supply tube 2 by the first valve closing suction operation, the amount of air in the ink supply path is smaller than that during the first valve closing suction operation. Therefore, the amount of pressure change per unit time shown in FIG. 7B is larger than that during the first valve closing suction operation. This is because the compressibility of the liquid (water or ink) is smaller than that of air, and the liquid (water or ink) hardly expands or contracts. Therefore, the less air and the more liquid, the lower the pressure of the suction pump 23. This is because the amount of pressure change becomes large.

FIG. 8A shows a state in which the on-off valve 3 is closed and the pressure inside the recording head 1 and the supply tube 2 is depressurized in the third valve closing suction operation, and FIG. 8B shows the pressure at that time. The measurement result is shown. In FIG. 8A, the ink is supplied to the inside of the supply tube 2 in the vicinity of the recording head 1 by the valve closing suction operation up to that point.

FIG. 9A shows a state in which the on-off valve 3 is closed and the pressure inside the recording head 1 and the supply tube 2 is depressurized in the fourth valve closing suction operation, and FIG. 9B shows the pressure at that time. The measurement result is shown. In FIG. 9A, ink is supplied to the inside of the recording head 1 by the valve closing suction operation up to that point.

In this way, as the valve closing suction operation is repeated, ink is sequentially supplied from the supply tube 2 to the recording head 1, the amount of air in the ink supply path decreases, and the amount of ink increases. Therefore, the amount of pressure change per unit time shown in FIGS. 8 (b) and 9 (b) increases in proportion to the number of repetitions of the valve closing suction operation.

The above is a series of steps related to the initial filling operation. If the ink tank 5 is not properly attached to the recording device 50 and the connection is poor, the ink will be ink even if the above-mentioned valve closing suction operation is repeated. A phenomenon occurs in which the ink is not supplied to the supply path. That is, since the ink is not supplied to the ink supply path and the amount of pressure change in the ink supply path per unit time does not change, the pressure measurement result does not change from the state shown in FIG. 5 (b).

Utilizing such a phenomenon, in the present embodiment, it is determined from the measurement result of the pressure change amount whether or not a connection failure has occurred between the ink tank 5 and the recording device 50. Specifically, the threshold value T1 of the pressure change amount is calculated in advance, and it is determined whether or not the pressure change amount per unit time after performing the valve closing suction operation a predetermined number of times exceeds the threshold value T1. In the present embodiment, the threshold value in 10 seconds (for example, the section of 5 seconds to 15 seconds in FIG. 5B) starting from 5 seconds after the start of suction by the suction pump 23 (after the lapse of the first time). T1 is set to 12 kPa. As described above, the pressure change amount in the 10 seconds in the first valve closing suction operation is about 9 kPa, but if there is no connection failure, the pressure change amount in the 10 seconds in the third valve closing suction operation is. Since it is about 20 kPa (see FIG. 8 (b)), it is larger than 12 kPa. Therefore, when the measured pressure change amount does not exceed the threshold value T1, it is estimated that the ink is not supplied to the ink supply path, and it can be determined that the connection is poor.

A flowchart for determining a connection failure in the initial filling operation will be described with reference to FIG. 10. In step S1101, the CPU 11 drives the on-off valve motor 35 to close the on-off valve 3, drives the suction pump motor 28, and performs a suction operation by the suction pump 23. After that, the CPU 11 stops the suction pump motor 28, drives the on-off valve motor 35 to open the on-off valve 3, and releases the negative pressure in the ink supply path. While this series of valve closing suction operations is performed N times, which is a predetermined number of times, and the negative pressure is charged by the suction pump 23 in each valve closing suction operation, the CPU 11 uses the pressure sensor 25 per unit time. Measure the amount of pressure change. In the present embodiment, the predetermined number of times (N times) is 3 times, and the unit time is 10 seconds from 5 seconds to 15 seconds after the start of suction.

In step S1102, the CPU 11 compares the measurement result measured by the pressure sensor 25 with the threshold value T1. If the amount of pressure change does not exceed the threshold value T1, that is, if ink is not supplied even after performing the valve closing suction operation a predetermined number of times, in step S1103, the CPU 11 has a poor connection between the ink tank 5 and the recording device 50. Is determined. After that, in step S1104, the CPU 11 notifies the user to reattach the ink tank 5 via the operation panel 54 or the like.

In step S1106, the CPU 11 determines whether or not the ink tank 5 is attached to the recording device 50. If the ink tank 5 is not installed, the CPU 11 waits until it is installed, and if it is installed, returns to step S1101 and restarts the initial filling operation.

On the other hand, if the pressure change amount exceeds the threshold value T1 in step S1102, the process proceeds to step S1105, and the CPU 11 repeats the valve closing suction operation a preset number of times (M times) to complete the initial filling operation. ..

As described above, by comparing the pressure change amount with the threshold value after performing the valve closing suction operation a predetermined number of times, it is possible to determine whether or not there is a connection failure between the ink tank 5 and the recording device 50. Therefore, after the initial filling sequence is completed, the time required for determining the connection failure is shortened and the throughput is improved as compared with the case where it is determined by checking the ejection state whether or not the ink is actually filled up to the recording head 1. do. Further, when it is determined that the connection is poor, the ink filling operation is temporarily stopped, the user resolves the connection failure, and the ink filling operation is restarted. Therefore, the throughput until the ink filling operation for the recording head 1 is completed is also improved. ..

Although the threshold value T1 is set in advance in the present embodiment, other examples can be adopted as the threshold value setting method. For example, the amount of pressure change for 5 to 15 seconds measured in the first valve closing suction operation is set as a threshold value, and then compared with the pressure change amount in the 10 seconds in the subsequent (for example, the third) valve closing suction operation. You can also judge by that. Further, from FIGS. 5 (b) and 8 (b), since the difference in the amount of pressure change between 5 seconds and 15 seconds in the first and third valve closing suction operations is about 11 kPa, the difference threshold value (for example). 5 kPa) may be set and used for judgment.

Further, as described above, since the negative pressure value generated by the fluid resistance of the discharge port provided in the recording head 1 and the filter 21 is about 20 kPa, the pressure change amount is measured 5 seconds after the start of the suction operation. It is configured to be acquired. Further, in the present embodiment, the pressure sensor 25 is provided between the recording head 1 and the suction pump 23, but the present invention is not limited to this, and by providing the pressure sensor 25 at a predetermined position in the internal flow path of the recording head 1 or the supply tube 2. Similar measurements can be made.

Further, in the present embodiment, the ink filling state in the ink supply path is determined by measuring the pressure, but the configuration is not limited to this, and the ink filling state may be estimated by other means. good. For example, it is possible to adopt a configuration in which the ink filling state in the ink supply path is estimated by an optical sensor and the presence or absence of a connection failure is determined based on the estimation result.

Although the ink for one color has been described in this embodiment, it is possible to provide the same configuration for inks of a plurality of colors. When there are a plurality of colors of ink, the discharge port surface 20 provided with a plurality of discharge port rows is covered with a common cap 22, and the pressure sensor 25 is arranged between the cap 22 and the common suction pump 23. You may. Since the flow path configuration is different for each color, if a common suction pump 23 is used, suction variation will occur to some extent. However, when there is a connection failure even with one color, the change in the amount of pressure change per unit time is smaller than when there is no connection failure, so it is possible to determine the presence or absence of the connection failure. For example, a threshold value per unit time is set for each color, and the total of the threshold values is set as the overall threshold value. If the amount of pressure change per unit time when the valve closing suction operation is performed a predetermined number of times does not exceed the overall threshold value, it is also possible to determine the number of ink tanks with poor connection according to the difference between the measurement result and the overall threshold value. Is.

(Modification example)
In this embodiment, the configuration in which the ink supply path is initially filled by performing the valve closing suction operation a plurality of times has been described. However, the present invention can also be adopted in a mode in which the suction operation is performed by the suction pump 23 without providing the on-off valve 3 in the middle of the supply tube 2, for example, when the supply tube 2 is short. Hereinafter, the case where the on-off valve 3 is not provided will be specifically described.

When the ink tank 5 is normally mounted, the same pressure change as in the first embodiment is observed due to the pressure loss of the ejection port and the filter 21 for 5 seconds from the start of suction. However, after that, while the ink is supplied to the ink supply path, the pressure change hardly occurs and the negative pressure value becomes almost flat. On the other hand, when there is a poor connection between the ink tank 5 and the recording device 50, the pressure changes in the same manner as in the first embodiment for 5 seconds from the start of suction, but after that, the suction time is larger than that of the ink. The longer the value, the higher the negative pressure.

As described above, even if the on-off valve 3 is not provided, the amount of pressure change differs depending on the presence or absence of poor connection of the ink tank 5. Therefore, it is possible to set a threshold value for the amount of pressure change as in the first embodiment and detect the presence or absence of a connection failure by comparing with the threshold value.

[Second Embodiment]
In the first embodiment, a method of determining a poor connection between the ink tank 5 and the recording device 50 has been described, but as another cause of ink not being ejected from the recording head 1, dust or the like is attached to the cap 22. Be done. If dust or the like adheres to the cap 22, the adhesion of the recording head 1 to the discharge port surface 20 weakens and the negative pressure (suction force) leaks, and the depressurization is sufficient even if the suction operation by the suction pump 23 is performed. I can't. As a result, since the negative pressure charged by the suction operation is smaller than that in the case where no dust or the like adheres, the amount of ink supplied is reduced even if the on-off valve 3 is opened and the negative pressure is released.

FIG. 11 shows a state in which the pressure sensor 25 is arranged between the recording head 1 and the suction pump 23 as in the first embodiment, and ink is filled by the valve closing suction operation in a state where dust or the like is attached to the cap 22. Is shown. FIG. 11A shows a state in which the on-off valve 3 is closed to reduce the pressure in the ink supply path, and FIG. 11B shows the pressure measurement result at that time.

As shown in FIG. 11B, when dust or the like adheres to the cap 22, the negative pressure value hardly changes even if the valve closing suction operation is performed. Normally, the negative pressure value due to the fluid resistance of the discharge port and the filter 21 is about 20 kPa for 5 seconds from the start of suction, so changes can be seen regardless of the amount of air in the ink supply path, but dust etc. is found on the cap 22. It can be seen that there is almost no change in the negative pressure value when it is attached.

On the other hand, when determining the connection failure between the ink tank 5 and the recording device 50 described in the first embodiment, the pressure change amount is constant for 5 seconds from the start of suction regardless of the presence or absence of the connection failure. Therefore, the detection of the negative pressure leak in the cap 22 and the detection of the connection failure between the ink tank 5 and the recording device 50 are different in the state of the pressure change, so that they can be detected separately. Specifically, in the case where the pressure change amount per unit time is less than the pressure loss of the discharge port row or the filter 21 (about 20 kPa in this embodiment) in the valve closing suction operation after the second time in the initial filling operation. Determines that the negative pressure is leaking in the cap 22.

A flowchart of the present embodiment for determining both a negative pressure leak (cap leak) and a connection failure in the cap 22 in the initial filling operation will be described with reference to FIG. In step S1301, the CPU 11 drives the on-off valve motor 35 to close the on-off valve 3, drives the suction pump motor 28, and performs a suction operation by the suction pump 23. After that, the CPU 11 stops the suction pump motor 28, drives the on-off valve motor 35 to open the on-off valve 3, and releases the negative pressure in the ink supply path. While this series of valve closing suction operations is performed P times, which is a predetermined number of times, and the negative pressure is charged by the suction pump 23 in each valve closing suction operation, the CPU 11 uses the pressure sensor 25 per unit time. Measure the amount of pressure change. In the present embodiment, the predetermined number of times (P times) is two times, and the unit time is 5 seconds from the start of suction to 5 seconds later.

In step S1302, the CPU 11 compares the measurement result measured by the pressure sensor 25 with the predetermined threshold value T2. In this embodiment, the threshold value T2 is 20 kPa. When the pressure change amount is less than the threshold value T2, in step S1303, the CPU 11 determines that a negative pressure leak (cap leak) has occurred in the cap 22. After that, in step S1304, the CPU 11 notifies the user of the cleaning of the cap 22 via the operation panel 54 or the like, and ends the flow. Here, the configuration may be such that the user can start the initial filling operation again after cleaning the cap 22.

If the pressure change amount is equal to or greater than the threshold value T2 in step S1302, the process proceeds to step S1305, and the CPU 11 performs the valve closing suction operation P + Q times, which is a predetermined number of times. While the negative pressure is being charged by the suction pump 23 in each valve closing suction operation, the CPU 11 measures the amount of pressure change per unit time using the pressure sensor 25. In the present embodiment, the predetermined number of times (P + Q times) is three times, and the unit time is 10 seconds from 5 seconds to 15 seconds after the start of suction.

In step S1306, the CPU 11 compares the measurement result measured by the pressure sensor 25 with the threshold value T1. When the pressure change amount does not exceed the threshold value T1, that is, when it is estimated that the ink is not supplied even after performing the valve closing suction operation a predetermined number of times, the CPU 11 records the ink tank 5 in step S1307. It is determined that the connection of the device 50 is defective. After that, in step S1308, the CPU 11 notifies the user via the operation panel 54 or the like to reattach the ink tank 5.

In step S1310, the CPU 11 determines whether or not the ink tank 5 is attached to the recording device 50. If the ink tank 5 is not installed, the CPU 11 waits until it is installed, and if it is installed, returns to step S1305 and restarts the valve closing suction operation.

On the other hand, if the pressure change amount exceeds the threshold value T1 in step S1306, the process proceeds to step S1309, and the CPU 11 repeats the valve closing suction operation a preset number of times (M times) to complete the initial filling operation. ..

As described above, it is possible to detect a leak of negative pressure in the cap 22 based on the amount of pressure change after performing the valve closing suction operation a predetermined number of times. Therefore, the time required for determination is shortened and the throughput is reduced as compared with the case where the ejection state of the recording head 1 is confirmed after the initial filling sequence is completed and it is determined that the ink is not filled up to the recording head 1. improves. Further, the difference in pressure change can be used to distinguish between the poor connection between the ink tank 5 and the recording device 50, the cause of non-ejection of the recording head 1 can be clarified, and the user can be urged to take appropriate measures. ..

1 Recording head 2 Supply tube (ink supply path)
5 Ink tank 11 CPU (judgment means, control means)
20 Discharge port surface 22 Cap 23 Suction pump (suction means)
25 Pressure sensor (estimating means, pressure measuring means)
50 Inkjet recording device

Claims (22)

A recording head having an ejection port surface provided with a plurality of ejection ports for ejecting ink,
An ink tank for accommodating ink supplied to the recording head, and
A cap that can be switched between a covered state that covers the discharge port surface and an exposed state that exposes the discharge port surface.
A suction means connected to the cap is provided.
A recording device that performs an ink filling operation for filling ink from the ink tank to the recording head by sucking the cap with the suction means when the cap is in the covered state.
A detection means for detecting the presence or absence of a defect in the ink flow path based on the pressure of the ink flow path provided between the ink tank and the suction means measured by the pressure measuring means during the ink filling operation. A recording device characterized by further provision. The recording device according to claim 1, wherein the detecting means detects the presence or absence of a defect in the ink flow path based on the amount of change in the pressure measured by the pressure measuring means per unit time. The first or second aspect of claim 1 or 2, wherein the pressure measuring means is provided in an ink flow path provided between the ink tank and the suction means, and measures the pressure at a predetermined position of the ink flow path. Recording device. The recording device according to any one of claims 1 to 3, wherein the pressure measuring means measures the pressure while suction is being performed by the suction means. The recording device according to claim 3, wherein the predetermined position is between the cap and the suction means. It is provided with an on-off valve provided in the middle of the ink tank and the recording head in the ink flow path and can be switched between an open state and a closed state.
In the ink filling operation, when the on-off valve is in the closed state and the cap is in the covered state, suction is performed by the suction means for a predetermined time, and then the on-off valve is brought into the open state. The recording device according to any one of claims 1 to 4, which is characterized. The recording device according to any one of claims 1 to 6, wherein the presence or absence of a defect in the connection between the ink tank and the recording device is detected based on the pressure. The recording device according to any one of claims 1 to 7, wherein the presence or absence of a defect in the cap is detected based on the pressure. The recording device according to any one of claims 1 to 8, wherein when it is detected that the ink flow path is defective, the ink filling operation is stopped. When the pressure value measured by the pressure measuring means is equal to or higher than the pressure value due to the fluid resistance between the on-off valve and the pressure measuring means, the detecting means determines the presence or absence of a defect in the ink flow path based on the pressure. The recording device according to claim 6, wherein the recording device is to be detected. The recording device according to claim 10, wherein the pressure value due to the fluid resistance is measured by the pressure measuring means after a lapse of a first time after the suction means starts suction. The recording device according to claim 11, wherein the suction means detects the presence or absence of a defect in the cap based on the amount of change in the pressure from the start of suction to the lapse of the first time. The claim is characterized in that the presence or absence of a connection failure between the ink flow path, the ink tank, and the recording device is detected based on the amount of pressure change per unit time measured after the lapse of the first time. 11 or 12 of the recording apparatus. The ejection port surface has a first ejection port row for ejecting a first ink and a second ejection port row for ejecting a second ink, and when the cap is in the covered state, the first ejection port row is provided. The recording device according to any one of claims 1 to 13, wherein both the discharge port row and the second discharge port row are covered. A recording head having an ejection port surface provided with a plurality of ejection ports for ejecting ink,
An ink tank for accommodating ink supplied to the recording head, and
A cap that can be switched between a covered state that covers the discharge port surface and an exposed state that exposes the discharge port surface.
A suction means connected to the cap is provided.
A recording device that performs an ink filling operation for filling ink from the ink tank to the recording head by sucking the cap with the suction means when the cap is in the covered state.
During the ink filling operation, the filling state of the ink flow path is estimated based on the pressure of the ink flow path provided between the ink tank and the suction means measured by the pressure measuring means, and the result of the estimation is performed. A recording device further comprising a determination means for determining the presence or absence of a defect in the ink flow path based on the above. It is provided with an on-off valve provided in the middle of the ink tank and the recording head in the ink flow path and can be switched between an open state and a closed state.
In the ink filling operation, when the on-off valve is in the closed state and the cap is in the covered state, suction is performed by the suction means for a predetermined time, and then the on-off valve is brought into the open state. The recording device according to claim 15. 16. The determination means is characterized in that the pressure value is acquired when the pressure value measured by the pressure measuring means is equal to or higher than the pressure value due to the fluid resistance between the on-off valve and the pressure measuring means. The recording device described in. A recording head having an ejection port surface provided with a plurality of ejection ports for ejecting ink,
An ink tank for accommodating ink supplied to the recording head, and
A cap that can be switched between a covered state that covers the discharge port surface and an exposed state that exposes the discharge port surface.
A suction means connected to the cap is provided.
A recording device that performs an ink filling operation for filling ink from the ink tank to the recording head by sucking the cap with the suction means when the cap is in the covered state.
Further, a detection means for detecting the presence or absence of a defect in the connection between the ink tank and the recording device based on the filling state of the ink flow path provided between the ink tank and the suction means during the ink filling operation. A recording device characterized by being provided. A recording head having an ejection port surface provided with a plurality of ejection ports for ejecting ink,
An ink tank for accommodating ink supplied to the recording head, and
A cap that can be switched between a covered state that covers the discharge port surface and an exposed state that exposes the discharge port surface.
A suction means connected to the cap is provided.
A recording device that performs an ink filling operation for filling ink from the ink tank to the recording head by sucking the cap with the suction means when the cap is in the covered state.
A recording device characterized in that during the ink filling operation, the presence or absence of a defect in the cap is detected based on the filling state of the ink flow path provided between the ink tank and the suction means. A recording head having an ejection port surface provided with a plurality of ejection ports for ejecting ink,
An ink tank for accommodating ink supplied to the recording head, and
A cap that can be switched between a covered state that covers the discharge port surface and an exposed state that exposes the discharge port surface.
A detection method for a recording device including a detection means connected to the cap.
An ink filling step of filling ink from the ink tank to the recording head by sucking the cap with the suction means when the cap is in the covered state.
In the ink filling step, a detection step of detecting the presence or absence of a defect in the ink flow path based on the pressure of the ink flow path provided between the ink tank and the suction means measured by the pressure measuring means, and a detection step of detecting the presence or absence of a defect in the ink flow path. A detection method characterized by having. A recording head having an ejection port surface provided with a plurality of ejection ports for ejecting ink,
An ink tank for accommodating ink supplied to the recording head, and
A cap that can be switched between a covered state that covers the discharge port surface and an exposed state that exposes the discharge port surface.
A method for detecting a recording device including a suction means connected to the cap.
An ink filling step of filling ink from the ink tank to the recording head by sucking the cap with the suction means when the cap is in the covered state.
In the ink filling step, a detection step of detecting the presence or absence of a defect in the connection between the ink tank and the recording device based on the filling state of the ink flow path provided between the ink tank and the suction means. A detection method characterized by having. A recording head having an ejection port surface provided with a plurality of ejection ports for ejecting ink,
An ink tank for accommodating ink supplied to the recording head, and
A cap that can be switched between a covered state that covers the discharge port surface and an exposed state that exposes the discharge port surface.
A method for detecting a recording device including a suction means connected to the cap.
An ink filling step of filling ink from the ink tank to the recording head by sucking the cap with the suction means when the cap is in the covered state.
The detection method comprising: a detection step of detecting the presence or absence of a defect of the cap based on the filling state of the ink flow path provided between the ink tank and the suction means in the ink filling step. ..

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