Ink-jet recording device

The present invention relates to an inkjet recording apparatus that records by ejecting ink and an equivalent thereof, and particularly to waste ink treatment.

Conventionally, as an inkjet recording device (hereinafter, also simply referred to as a recording device), an inkjet recording head (hereinafter, also simply referred to as a recording head) mounted on a carriage that reciprocates across a recording medium (paper or the like) may be used. There are many. As the recording head moves across the recording medium, the control unit activates the recording element provided in the ejection unit of the recording head to eject ink droplets from the ejection nozzle to form an image or characters on the recording medium. Discharge. Ink is replenished from the ink tank to the recording head.

In an inkjet recording device, foreign matter such as paper dust or dust adheres to the ink ejection part of the recording head, the ink in the ejection part dries and the viscosity increases or sticks, resulting in ejection failure or inability to eject. There is a fear. As a means for preventing such a problem, a configuration is adopted in which the ink ejection portion is sealed by a cap formed of a rubber-like elastic member during non-recording. However, when the ink is not recorded, the ink in the surface layer of the ink ejection part may thicken when the ink is left in the capping state for a long time only by dealing with the capping state in which the ink ejection part is sealed. Cannot eject ink completely.

Therefore, before recording, so-called preliminary ejection is performed in which the state of the ink in the surface layer of the ink ejection portion is restored to the normal state by first ejecting ink that does not contribute to recording. Further, when the ink state of the surface layer of the ink ejection portion is not restored to normal by the preliminary ejection, the ink of the surface layer of the ink ejection portion is forcibly sucked or pressurized by a pump or the like. By sucking or pressurizing the ink in this way, the ink is discharged in the capped state to restore the ink in the ink ejection portion to the normal state. Further, even during the recording operation, ink may gradually adhere to the ejection portion (ejection port surface) of the recording head due to the ejection of ink, which may cause ejection failure. Therefore, the recording head is spared at a predetermined timing. The discharge operation is performed. The ink discharged from the ejection port by the preliminary ejection operation or the suction operation as described above is processed in the apparatus as waste ink. In addition, the ink ejected to the outside of the recording medium during borderless printing is also treated as waste ink.

A waste ink recovery device for storing such waste ink is provided in the recording device. There is a configuration in which this waste ink recovery device is integrated with an ink tank to collect waste ink in the ink tank. For example, Patent Document 1 discloses a recording device equipped with a plurality of ink tanks having an ink bag and a waste ink absorber. Further, Patent Document 2 discloses a recording device in which waste ink sucked under negative pressure by a recovery system is reused as black ink.

<patcit num="1"><text>Japanese Unexamined Patent Publication No. 2-29345</text></patcit><patcit num="2"><text>Japanese Unexamined Patent Publication No. 2004-136482</text></patcit>

<p> However, in the conventional method of collecting waste ink, the suction pressure of the recovery system is absorbed by the waste ink absorber or the like and discharged, so that the waste ink mixed with air returns to the ink tank. It was. Therefore, the discharge destination needs to be open to the atmosphere for gas-liquid exchange, and when a large amount of ink is collected, waste ink leaks from the air opening.</p><p> Ink is supplied to the recording head by pressurizing an ink bag formed in a variable shape by a flexible film or the like, or by having an pressurizing / depressurizing pump in a supply flow path located between the ink bag and the recording head. In many cases, it is supplied. The recording device has a waste ink reservoir that collects waste ink from multiple locations by preliminary ejection or suction operation and temporarily stores it, and collects the waste ink collected in the waste ink reservoir to some extent in an ink tank. There is. A dedicated waste ink container is required to collect in the ink tank, and by creating a negative pressure around the sealed and shrinkable waste ink container, the waste ink container in the recording device can be removed from the waste ink container in the ink tank. It becomes possible to collect waste ink.</p><p> However, when the ink bag and the waste ink container are held in the ink tank, the ink supply by the pressurizing / depressurizing pump between the supply channels is hindered by the negative pressure around the waste ink container when collecting the waste ink. There are times. Therefore, there is a problem that the supply of recording ink and the collection of waste ink cannot be performed at the same time. Furthermore, since waste ink cannot be collected at the same time during recording, if a waste ink collection instruction is issued from the recording device main body side, the ink tank must wait for the waste ink to be collected after the recording is completed. Could not be exchanged.</p><p> Therefore, an object of the present invention is to provide an inkjet recording apparatus capable of supplying recording ink and collecting waste ink at the same time and replacing the ink tank without waiting for the collection of waste ink.</p>

<p> Therefore, the inkjet recording apparatus of the present invention uses a recording head that ejects ink, an ink supply path that can supply the ink from the ink tank to the recording head, and waste ink ejected from the recording head. In an inkjet recording apparatus provided with a waste ink flow path for collecting to a tank, the ink supply path is provided with a first valve capable of opening and closing the ink supply path, and the first valve is provided. A pressurizing chamber capable of increasing or decreasing the internal pressure by the first pump is provided between the valve 1 and the recording head, and the waste ink flow path opens and closes the waste ink flow path. It is characterized in that a second valve that can be used is provided.</p>

<p> The inkjet recording apparatus of the present invention includes a first valve capable of opening and closing the ink supply path in the ink supply path. Further, the inkjet recording apparatus of the present invention is provided with a pressurizing chamber between the first valve and the recording head, which can pressurize and depressurize the internal pressure by the first pump, and waste ink in the waste ink flow path. It has a second valve that can open and close the ink flow path. As a result, it has become possible to realize an inkjet recording apparatus in which the ink for recording can be supplied and the waste ink can be collected at the same time, and the ink tank can be replaced without waiting for the collection of the waste ink.</p>

(First Embodiment) Hereinafter, the first embodiment of the present invention will be described with reference to the drawings. The present invention is not limited to these embodiments, but can be further combined, and any modifications or modifications contained within the concept of the present invention described in the claims can be made, and thus the spirit of the present invention can be made. Of course, it can be applied to other technologies belonging to.

FIG. 1 is a schematic view showing the flow of ink in the inkjet recording device (hereinafter, also simply referred to as a recording device) 1 in the present embodiment so as to be understood. In the inkjet recording apparatus 1, the ink supplied from the ink tank 10 is supplied to the recording head 30 via the ink supply tube (ink supply path) 20. The recording head 30 reciprocates in a direction orthogonal to the recording medium transport direction to print (hereinafter, also referred to as recording) on a recording medium (not shown). The ink ejected from the recording head 30 that was not used for printing (hereinafter referred to as waste ink) is first collected in the suction cap 40 and the preliminary spout 41, and passes through the waste ink collection tube (waste ink flow path) 42. Then, it is temporarily stored in the waste ink reservoir 43. The waste ink stored in the waste ink reservoir 43 is appropriately collected from the waste ink reservoir 43 to the ink tank 10 via the waste ink recovery tube 42.

The ink tank 10 is formed of a shape-variably formed ink bag body 11 which is a first liquid storage portion, a rubber stopper 12 which seals an ink supply port, and a shape-variable shape which is a second liquid storage portion. It is provided with a waste ink bag body 13 and a rubber stopper 14 that seals a waste ink collection port. Further, the ink tank 10 has a fixed volume space for accommodating a rubber stopper 15 for hermetically connecting the decompression pump (second pump) 52, which is a second pressure generating source, and the ink bag body 11 and the waste ink bag body 13. It is equipped with a storage case 16 with. At one end of the ink supply tube 20, an ink needle, which is a hollow tube with a sharp tip, is inserted into the rubber stopper 12 to enable ink to be taken out to the ink supply tube 20. Similarly, one end of the waste ink recovery tube 42 is a hollow tube having a sharp tip, and an ink needle is inserted into the rubber stopper 14 to enable recovery of waste ink from the waste ink recovery tube 42. At the same time that each ink needle is inserted into each rubber stopper, the pressure reducing pump 52, which is the second pressure generating source, is connected to the storage case 16. The decompression pump 52 can decompress the inside of the case over the entire area.

The ink supplied from the ink tank 10 is the ink supply pipe 20, the pressurizing chamber 21, which is the third liquid storage part, the supply valve (first valve) 22, and the pressurizing / depressurizing pump (first pressure generating source). The first pump) is supplied to the recording head 30 via a supply path consisting of 50. The supply valve 22, which is an on-off valve for opening and closing the supply path, is installed between the ink tank 10 and the pressurizing chamber 21, and opens and closes as needed. A certain amount of the following ink can be stored in the pressurizing chamber 21. The pressurizing / depressurizing pump 50 acts on the pressurizing chamber 21 to store ink from the ink tank 10 in the pressurizing chamber by depressurizing the pressurizing chamber 21, and pressurizes the pressurizing chamber 21 to pressurize the ink. The ink stored in the chamber 21 can be supplied to the recording head 30.

A part of the wall of the recording head 30 is made of a flexible film 31. The flexible film 31 expands and contracts in response to a pressure change inside the recording head 30 due to ink consumption. The expansion and contraction motion of the flexible membrane 31 is transmitted to the arm 32 connected to the flexible membrane 31, and further transmitted to the valve 33 connected to the tip of the arm 32 opposite to the flexible membrane 31. The valve 33 closes the connection portion between the ink supply tube 20 and the recording head 30, and is opened and closed as the ink is consumed by the mechanism as described above.

Waste ink is inevitably generated in order to maintain the reliability of the recording head 30. Waste ink can be roughly classified into those discarded in the suction cap 40 and those discarded in the preliminary discharge port 41. The suction cap 40 is located outside the printing area and is used to protect and moisturize the ink ejection surface of the recording head 30 during non-printing. It is used to suck and recover the discharge surface of the head 30. The waste ink collected on the surface of the suction cap 40 by the preliminary ejection is collected by the suction pump 51, and is stored in the waste ink reservoir 43 via the waste ink recovery pipe 42. When suction recovery is performed, the ink ejection surface of the recording head 30 and the suction cap 40 are sealed, and the suction pump 51 operates to suck out ink from the recording head 30 and pass through the waste ink recovery tube 42. Then, it is stored in the waste ink reservoir 43. The preliminary discharge port 41 may be installed on the side opposite to the suction cap 40 that is out of the print area, or may be installed at an appropriate place in the print area. The waste ink collected in the preliminary ejection port 41 is stored in the waste ink reservoir 43 via the waste ink recovery pipe 42 due to gravity.

The bottom or the vicinity of the bottom of the waste ink reservoir 43 is connected to the ink tank 10 by the waste ink recovery tube 42. A waste ink valve (second valve) 44 is provided in the middle of the waste ink recovery pipe. When the inside of the ink tank 10 is decompressed by the decompression pump 52, the waste ink stored in the waste ink reservoir 43 flows out to the waste ink recovery pipe 42, and is finally collected in the waste ink bag 13.

Next, the flow of ink and the movement of each part in the recording operation will be described.

(Initial filling operation) FIG. 2 is a diagram showing a state in which the supply valve 22 of the recording device 1 is opened. The ink is drawn out from the ink tank 10 to the ink supply pipe 20 by depressurizing the inside of the pressurizing chamber 51 using the pressurizing / depressurizing pump 50. When the supply valve 22 is opened and the pressurizing / depressurizing pump 50 is operated in the depressurizing direction, the ink drawn out from the ink tank 10 is stored in the pressurizing chamber 21. When the ink is stored in the pressurizing chamber 21 up to a predetermined threshold value, the depressurization is stopped and the supply valve 22 is closed as shown in FIG. Next, the pressurizing / depressurizing pump 50 is operated in the pressurizing direction to pressurize the ink stored in the pressurizing chamber 21 to a predetermined pressure. However, since the force of the valve 33 in the recording head 30 to close the ink supply tube 20 is larger than the predetermined pressure of the pressurized ink, the valve 33 opens and the ink supply tube 20 and the recording head 30 communicate with each other. There is no such thing. Therefore, it is necessary to reduce the pressure inside the recording head 30 by sealing the suction cap 40 with the recording head 30 and operating the suction pump 51. As a result, the valve 33 is opened and ink can be supplied to the recording head 30. When a predetermined amount of ink is supplied into the recording head 30, the suction pump 51 is stopped and the suction cap 40 is separated from the recording head 30. As a result, the ink is supplied until the valve 33 is closed due to the balance with the negative pressure value in the recording head 30, and then the ink supply is stopped.

(Ink supply operation during printing) When the ink in the recording head 30 is consumed by printing, the negative pressure in the recording head 30 increases. As a result, since the valve 33 opens, the ink pressurized in the pressurizing chamber 21 is supplied to the recording head 30, and the valve 33 is closed by the balance with the negative pressure in the recording head 30. During printing, the ink stored in the pressurizing chamber 21 is supplied to the recording head 30 by repeating the above operation. When the amount of ink stored in the pressurizing chamber 21 becomes equal to or less than a predetermined threshold value, the operation of supplying ink from the ink tank 10 to the pressurizing chamber 21 is performed. That is, the pressurizing operation of the pressurizing / depressurizing pump 50 is stopped, the supply valve 22 is opened when the pressurizing of the pressurizing chamber 21 is released, and then the pressurizing / depressurizing pump 50 is operated in the depressurizing direction. The ink in 10 is supplied to the pressurizing chamber 21. At this time, since the valve 33 in the recording head 30 remains closed, the ink in the recording head 30 is not supplied to the pressurizing chamber 21. When the amount of ink in the pressurizing chamber 21 reaches a predetermined amount, or when a predetermined time elapses after the pressurizing chamber 21 is depressurized, the supply valve 22 is closed and the pressurizing / depressurizing pump 50 is operated in the pressurizing direction. As a result, the ink supply to the pressurizing chamber 21 is terminated.

(Waste ink recovery operation) FIG. 3 is a diagram showing a state in which the waste ink valve 44 of the recording device 1 is opened. When the amount of waste ink stored in the waste ink reservoir 43 exceeds a predetermined threshold value, an operation of collecting the waste ink in the ink tank 10 is performed. By opening the waste ink valve 44 and operating the decompression pump 52, the waste ink stored in the waste ink reservoir 43 is discharged to the waste ink recovery pipe 42, and finally collected in the waste ink bag body 13. The pressure reducing pump 52 may be operated first to sufficiently reduce the pressure inside the ink tank 10, and then the waste ink valve 44 may be opened. When the amount of waste ink in the waste ink reservoir 43 becomes less than a predetermined amount, or after a predetermined time from the start of the waste ink collection operation, the waste ink valve 44 is closed. Further, by opening the pressure reducing pump 52 to the atmosphere, the negative pressure in the ink tank 10 is eliminated, and the waste ink recovery operation is completed.

(Recovery operation during printing) FIG. 4 is a flowchart of ink supply and waste ink recovery operation during printing. Hereinafter, the waste ink recovery operation during printing will be described with reference to the flowchart. In the flowchart, steps S001 to S007 are ink supply operations to the recording head 30, and since they have already been described, the description thereof will be omitted here, and the waste ink recovery operations after step S008 will be described.

In step S008, it is confirmed whether the waste ink in the waste ink reservoir 43 is equal to or higher than the threshold value. If it is below the threshold value, the process returns to step S001 and printing is continued, but if it is above the threshold value, the process proceeds to step S009. From step S009 to step S012, ink is supplied to the recording head 30 in the same manner as described above. The pressurizing / depressurizing pump 50 is pressurized in step S012, and the waste ink valve 44 is opened in step S013. After that, in step S014, the pressure reducing pump 52 is depressurized to reduce the pressure inside the ink tank 10, so that the waste ink in the waste ink reservoir 43 is guided into the waste ink bag 13 of the ink tank 10. The pressure reducing pump 52 puts the ink tank 10 in a negative pressure state, but the supply valve 22 is in a closed state, so that the ink can be supplied to the recording head 30 without being affected by the pressure value in the pressurizing chamber. it can. Then, the process proceeds to step S015, the waste ink valve 44 is closed, and the pressure reducing pump 52 is opened to the atmosphere in step S016. Then, in step S017, the waste ink collection operation is completed.

In this way, bags for ink and waste ink are provided in the same ink tank, and valves and pumps are provided in the paths of each ink (ink and waste ink) connected to each bag. Further, in the ink path, a pressurizing chamber connected to a pump capable of storing ink is provided between the recording head and the valve. As a result, the supply of recording ink and the collection of waste ink can be performed at the same time, and by collecting the waste ink during recording, the ink tank can be replaced without waiting for the time required for collecting the waste ink. We were able to realize a possible inkjet recording device.

(Second embodiment) Hereinafter, a second embodiment of the present invention will be described with reference to FIG. Since the basic configuration of the present embodiment is the same as that of the first embodiment, only the characteristic configuration of the present embodiment will be described below.

FIG. 5 is a schematic view showing the flow of ink in the inkjet recording apparatus of the present embodiment so as to be understood. This embodiment has a configuration in which a waste ink reservoir is not provided as in the first embodiment. The inside of the ink tank 10 is configured such that the atmospheric pressure is maintained at the air opening 53 regardless of the shapes of the ink bag 11 and the waste ink bag 13. Further, one end of the waste ink collection pipe 42 is connected to the discharge port of the suction pump 51, and the other end is connected to the waste ink bag body 13.

During printing, the recording head 30 performs preliminary ejection to the suction cap 40. Before sucking the waste ink from the suction cap 40 by preliminary ejection, the ink bag body 11 supplies the ink to the pressurizing chamber 21 by the pressurizing / depressurizing pump 50. That is, ink is supplied to the pressurizing chamber 21 by opening the supply valve 22 and setting the pressurizing / depressurizing pump 50 to a negative pressure. After that, the supply valve 22 is closed, the waste ink in the suction cap 40 generated by the preliminary ejection of the recording head 30 is sucked by the suction pump 51, and the waste ink directly passes through the waste ink recovery tube 42 to the waste ink bag body 13. It will be collected.

Due to the collection of waste ink in the waste ink bag 13, the ink bag 11 receives some pressure in the storage case 16. Even at this time, if the supply valve 22 is in the closed state, the ink in the pressurizing chamber 21 is not affected by the pressure fluctuation, and stable printing can be continued.

In this way, in a configuration in which a waste ink reservoir is not provided in the waste ink collection path, each ink bag for ink and each bag body for waste ink are provided in the same ink tank, and each ink connected to each bag body ( Ink and waste ink) will be provided with valves and pumps, respectively. Further, in the ink path, a pressurizing chamber connected to a pump capable of storing ink is provided between the recording head and the valve. As a result, the supply of recording ink and the collection of waste ink can be performed at the same time, and by collecting the waste ink during recording, the ink tank can be replaced without waiting for the time required for collecting the waste ink. We were able to realize a possible inkjet recording device.

<figref num="1">It is a schematic diagram which showed so that the flow of ink in the inkjet recording apparatus in 1st Embodiment can be understood.</figref><figref num="2">It is the figure which showed the state which the supply valve of a recording apparatus was opened.</figref><figref num="3">It is a figure which showed the state which the waste ink valve of a recording apparatus was opened.</figref><figref num="4">It is a flowchart of ink supply and waste ink collection operation during printing.</figref><figref num="5">It is a schematic diagram which showed so that the flow of ink in the inkjet recording apparatus of 2nd Embodiment can be understood.</figref>

Code description

10 ink tank 11 Ink bag 13 Waste ink bag 20 Ink supply tube 21 Pressurization chamber 22 Supply valve 30 recording head 33 valve 40 suction cap 42 Waste ink recovery tube 44 Waste ink valve 50 Pressure reducing pump 51 Suction pump 52 Decompression pump