JP4602116B2 - Ink jet recording apparatus, tube pump, and liquid feeding method - Google Patents

Description

  The present invention relates to an ink supply system from a main tank, which is an ink supply source, to a sub tank and a recording head, of an ink jet recording apparatus that records an image on a recording medium by ejecting ink droplets from a recording head.

  The serial printing type ink jet recording apparatus as shown in FIG. 7 is reciprocated in at least a main scanning direction which is mounted on a carriage 2 and transports a recording medium in a sub scanning direction (not shown) and is orthogonal to the sub scanning direction. The moving recording head 1 is provided, and an image is formed by ejecting ink droplets from the recording head 1 at a desired timing and landing on the surface of the recording medium based on print data.

  Particularly, in a large-sized ink jet recording apparatus that forms a large image on a relatively large recording medium, a large capacity main tank 5 is provided on the ink jet recording apparatus main body side as an ink supply source in order to consume a large amount of ink. Further, a sub-tank 9 is provided in the middle of the ink supply path 7 connecting the main tank 5 and the recording head 1 to supply ink to the recording head 1.

  A service station for cleaning the recording head 1 is provided outside the non-printing area in the main scanning direction, and a capping unit 3 for sealing the nozzle forming surface of the recording head 1 is disposed in this service station. Has been. A negative pressure can be applied to the capping unit 3 by the suction pump 4, and an air release valve is provided so that the negative pressure state of the capping unit 3 can be opened. With such a configuration, it is possible to remove dust accumulated in the recording head 1 (cleaning operation) and perform an initial ink filling operation into the apparatus.

  For the purpose of simplifying the device configuration and reducing costs, a pressure pump 13 is installed in the middle of the ink supply path 12 from the sub tank 9 to the recording head 1 instead of using the suction pump 4 for the capping unit 3. In some cases, the cleaning operation and the initial ink filling operation into the apparatus are performed by pressurizing the ink. As the pressurizing pump 13 used at this time, a piston pump, a tube pump, or the like is used. Among them, tube pumps are becoming the mainstream of pressurizing means in recent years because of easy control of pressurization pressure, ink flow rate, ink pressurization speed, etc. and easy manufacture.

As shown in FIG. 8, the general tube pump has, for example, an arcuate guide member 16, a tube 14 disposed along the inner periphery thereof, and at least one press that rotates by pressing the tube against the guide member 16. It is formed by a member (roller) 15 and the like, and the roller 15 moves while being crushed so as not to open the tube 14, thereby sending the liquid or gas in the tube forward. For this reason, when the tube pump is stopped, the ink supply path is closed. Therefore, a path 12b that bypasses the pressure pump is provided in the ink supply path when the pressure pump is used to secure the ink supply path at the time of ink discharge. Switching means 13a, 13b for switching between are provided. As this switching means, for example, a solenoid valve, a three-pronged joint or a three-way cock is used.
Japanese Patent Laid-Open No. 11-190280

  In an ink supply system that performs filling operation and cleaning operation by ink pressurization as described above, in the ink supply path at the time of ejection, the solenoid valve, the three-pronged joint, or the three-way cock is reduced in the complexity of the flow path shape and the cross-sectional area As a result, pressure loss increases and ink does not flow easily. When the pressure loss of the ink supply system becomes large, the ink supply amount tends to be insufficient at the time of ink discharge, and there is a possibility that the discharge stability and the print quality may be deteriorated. Accordingly, the present invention provides a tube pump that reduces pressure loss in the ink supply path, reduces the number of components, and simplifies the configuration, and an ink jet recording apparatus using the tube pump.

  The tube pump according to the present invention has a pump body in which a space portion is formed, an arc-shaped guide member is formed on an inner surface of the space portion over a predetermined angle range, and an opening communicating with the space portion is formed. A tube laid along the guide member and led out from the opening and inserted through the pump body, and driven to rotate about an axis concentric with the guide member. At least one pressing member that presses against the guide member, a driving unit that controls the rotational driving, a position detecting unit that detects the position of the pressing member, and a flow path in the tube when the pump is stopped. A flow path securing means is provided.

  Moreover, in the tube pump according to the present invention, the flow path securing means is formed by one or more relief portions of the guide member that are not pressed by the guide member and the pressing member. As a result, a predetermined pressure can be obtained when driven as a pressure pump without providing a path that bypasses the pressure pump in the ink supply path, and performance as an ink supply path can be obtained when the pump is stopped. Can do.

  The ink jet recording apparatus of the present invention is an ink jet recording apparatus that discharges ink from a recording means and records it on a recording material, and a space is formed inside the ink supply path for transporting the ink. An arc-shaped guide member is formed on the inner surface of the space portion over a predetermined angle range, and a pump body formed with an opening communicating with the space portion; and laid along the guide member and from the opening portion. A tube led out and disposed through the pump body, and at least one pressing member that is rotationally driven about an axis concentric with the guide member and presses the tube against the guide member; Drive means for controlling the rotational drive, position detection means for detecting the position of the pressing member, and flow path securing means for securing the flow path in the tube when the pump is stopped are provided. It characterized by having a tube pump that.

Further, the ink supply path at the time of ink ejection in the ink jet recording apparatus of the present invention is characterized by passing through a tube in the tube pump. Thereby, without having a plurality of paths in the ink supply system, it is possible to reduce the pressure loss of the ink supply system and prevent the discharge stability and the deterioration of the print quality. Further, by reducing the number of parts, it is possible to obtain a reduction in device cost and an improvement in reliability.

  As described above, the apparatus configuration of the tube pump and the ink supply system of the present invention expresses a desired pressure when the pump is pressurized, and plays a role as an ink supply path without increasing the pressure loss when ink is ejected from the recording head. be able to. As a result, a tube pump that reduces pressure loss in the ink supply path, reduces the number of components, and simplifies the configuration without having a plurality of ink supply paths in the apparatus, and an ink jet recording apparatus using the tube pump are realized. Can do.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a configuration diagram schematically showing a basic configuration relating to ink supply of the ink jet recording apparatus of the present invention. In FIG. 1, a carriage 2 is mounted with a recording head 1 and supported on a recording medium (not shown) arranged below the recording head 1 so as to be able to reciprocate in a main scanning direction perpendicular to the conveyance direction of the recording medium. .

  The main tank 5 serving as an ink supply source has a structure that can be attached to a main tank storage portion 6 provided at a predetermined position in the apparatus. The main tank 5 is equipped with an air shielding container 5a capable of storing ink sufficiently deaerated during the ink injection process. In this example, the air shielding container 5a is a gusset type formed of a flexible material. This is a bag-shaped ink pack, and a sufficient quality gas barrier property is secured by providing an aluminum foil layer on one layer of a flexible material.

  In addition, a rubber septum (not shown) is provided at the coupling end of the air shielding container 5a with the ink supply path, and the air shielding container is formed by the insertion coupling of the needle 6a provided in the main body main tank storage section 6. The main tank storage unit 6 is configured to be detachable without reducing the deaeration rate of the deaeration ink stored in 5a. The needle 6a provided in the main tank storage unit 6 is connected to an ink supply path 7 made of a flexible tube, and one end of the ink supply path 7 is extended from the ink inlet of the sub tank 9 with a flexible tube. It is connected to the coupling member 10 provided at the end portion. A suction pump 8 for pumping the degassed ink stored in the main tank 5 to the sub tank 9 is disposed in the middle of the ink supply path 7.

  Next, the sub-tank 9 is provided with a flexible ink bag, and the coupling member 10 provided at the terminal portion extended from the ink outlet port of the sub-tank 9 by the flexible tube has a flexible tube. One end of the ink supply path 12 is connected, and the other end of the ink supply path 12 is connected to the recording head 1. In this embodiment, the sub-tank 9 can be easily attached to a sub-tank holder (not shown) disposed at a predetermined position of the main body by detaching the coupling member 10 provided in the vicinity of the ink outflow inlet and the ink supply paths 7 and 12. The sub-tank 9 can be attached or removed. A pressure pump 13 is provided in the ink supply path 12 in the middle of the ink supply path 12 in order to satisfactorily finish the meniscus formed on the nozzle surface of the recording head 1. In the present invention, the tube pump shown below is used as the pressurizing pump 13. The structure of this tube pump will be described in detail later.

  Although the form of this figure demonstrated the structure containing the one recording head 1 corresponding to 1 color of printing, in the case of a multi-color printing / same color multi-recording head structure as an inkjet recording device, for example, a plurality of main tanks 5 and a plurality of The same number of sub-tanks 9 may be provided, and the sub-tanks 9 may be configured to correspond one-to-one to serve as an ink supply path to the recording head 1. It does not exclude the form.

  FIG. 2 is a diagram schematically showing a cross-section of the first embodiment of the tube pump 13 of the present invention installed in the ink supply path from the sub tank 9 to the recording head 1. FIG. 3 is a diagram showing a control configuration of the tube pump of the present invention.

  The tube pump according to the present invention includes a pump body 21 in which a space portion is formed, an inner surface of the space portion is formed in an arc shape over a predetermined angle range, and an opening communicating with the space portion is formed. Inside the space, there are an elastic tube 14, a guide member 16 that is a part of the pump body and guides the tube 14 on the inner periphery, and a roller 15 that is a pressing member for pressing the tube 14 against the guide member 16. Has been placed. In the tube pump 13 of the present embodiment, the predetermined angle is about 180 degrees, and the tube 14 is arranged in a curved U-shape inside the tube pump. The roller 15 is fixed to a guide plate 22. The guide plate is pivotally supported by a pump shaft 18 and connected to a motor 23 so that it can be driven to rotate.

  Further, a part of the guide member 16 is formed with a relief portion 17 that can be escaped without being pressed even when the tube 14 is sandwiched between the roller 15 and the guide member 16. When the roller 15 is stopped at a position facing the escape portion 17, fluid such as ink in the tube pump flows through the escape portion 17 without closing the flow path by the roller 15 and the guide member 16. I can do it.

  If the volume of the escape portion is small, the pressure of the inflowing ink is concentrated, so that the wear of the tube 14 and the guide member 16 corresponding to this portion becomes severe. Further, depending on the control method, it is difficult to stop the roller 15 so as to match the escape portion, and the escape flow rate is not sufficient.

  On the other hand, if the escape portion 17 is too large, the pump efficiency is deteriorated and ink cannot be sufficiently sent to the recording head 1. If the escape portion is too large, it is difficult to completely close the flow path of the tube 14 and lock the ink flow of the tube pump by the closing portion 20 and the roller 15 which are portions of the guide member 16 other than the escape portion. It becomes. Therefore, the relief portion angle θf constituting the relief portion 17 depends on the predetermined angle, but when the angle of the tube 14 to be compressed is 180 degrees or more and the relief portion 17 is one place, it is 30 degrees to 90 degrees. A degree is appropriate. Of these, 50 degrees is optimal.

  When the roller 15 is rotated around the pump shaft 18, a fluid such as liquid or gas existing inside the tube 14 is transferred. For example, when the roller 15 is rotated clockwise, in the tube 14, the tube end 19 a side becomes negative pressure, and the fluid existing in the tube end 19 a is sucked into the tube 14. Conversely, since the tube end 19b side is at a positive pressure, the fluid present in the tube 14 on the tube end 19b side is discharged from the tube end 19b. That is, the fluid is transferred from the tube end 19a side to the 19b side.

Next, the control of the tube pump 13 in the initial filling and cleaning operation of the recording head 1 will be described with reference to the flowchart of FIG. When the recording head is not filled with ink due to the assembly of the apparatus or replacement of the recording head or when the recording head is disconnected or deflected, the initial filling and cleaning operation, that is, the tube pump 13 is activated to return to the recording head. Ink is applied to the recording head (S1). In the initial filling operation and the cleaning operation, the procedure is the same, but in general, the pressurization time is longer in the initial filling. The pressurization time varies depending on the configuration of the supply path. After pressurizing for a certain time (S2), the flow is stopped in the state of FIG. 6 in which the flow path of the tube 14 is closed at the closed portion 20 other than the roller 15 and the escape portion 17 of the guide member 16 (S3). . The stop location is controlled by detecting a magnet sensor 24 (Hall element) mounted on the pump body 21 with a magnet mounted on the guide plate 22. By holding for several seconds in the stopped state of FIG. 6 (S4), the negative pressure in the pump tube, the supply path to the print head, and the print head can be eliminated. Thereafter, the roller 15 is stopped at a position where the roller 15 faces the escape portion 17, that is, in a state where the ink flow path is secured (opened) (the state shown in FIG. 5) in the tube 14 of the tube pump (S5). Thus, the ink supply path between the recording head and the sub tank communicates, and ink can be discharged.
The position detection sensor is not limited to the one using a magnet, and a rotary encoder, a touch sensor (microswitch), a photo sensor, or the like may be used.

The figure which shows typically the basic composition which concerns on the ink supply of the inkjet recording device which concerns on embodiment of this invention. Schematic diagram of tube pump according to the present invention The figure which shows the control structure of the tube pump which concerns on this invention Flowchart for control during initial filling and cleaning operations according to the present invention Schematic diagram of the tube pump according to the present invention when the tube is opened Schematic diagram of the tube pump according to the present invention when the tube is closed The figure which shows typically the basic composition which concerns on the ink supply of the conventional inkjet recording device Schematic diagram of a conventional tube pump

Explanation of symbols

1 Recording head (recording means)
4 Suction pump 5 Main tank 7 Ink supply path 8 Suction pump 9 Sub tank 12 Ink supply path 13 Pressure pump (tube pump)
13a switching means 13b switching means 14 tube 15 roller (pressing member)
16 Guide member 17 Escape portion 20 Closed portion 21 Pump body 22 Guide plate 24 Sensor 25 Controller

Claims (14)

In an ink jet recording apparatus that records on a recording material by discharging ink from a recording means,
An elastic tube, and an arcuate guide member for guiding the tube;
At least one pressing member that presses the tube against the guide member;
An escape portion that allows the tube to escape without being pressed by the pressing member to a part of the guide member;
An ink jet recording apparatus comprising: a tube pump comprising: an ink supply path as the recording means pressurizing pump. The ink jet recording apparatus according to claim 1, wherein the pressing member presses the tube by rotating inside the guide member. 3. The ink jet recording apparatus according to claim 2, wherein the escape portion is a concave portion in which an inner surface of the guide member is recessed with a predetermined depth outward from a rotation center of a pump shaft of the tube pump. The inkjet recording apparatus according to claim 3, wherein the recess has an angle of a recess range of 30 degrees or more and 90 degrees or less with the rotation center as a center. The inkjet recording apparatus according to claim 4, wherein the recess has an angle of a recess range of 50 degrees with the rotation center as a center. 6. The relief portion according to claim 2, wherein the relief portion is located on an inner surface of the guide member that is opposed to a region where the pressing member does not contact the tube with a rotation center of a pump shaft of the tube pump as a center. The ink jet recording apparatus according to any one of the above. One surface of the escape portion farthest from the rotation center of the pump shaft of the tube pump toward the outside of the tube pump is a bottom surface of the escape portion,
One surface of the guide member other than the escape portion is the surface of the guide member,
The ink jet recording apparatus according to claim 2, wherein a taper shape is provided at a boundary between the bottom surface and the surface. The ink jet recording apparatus according to claim 1, wherein the pressing member is a roller that presses the tube by a rotational movement of a motor. The ink jet recording apparatus according to claim 8, wherein two rollers are provided. 10. The ink jet recording apparatus according to claim 9, wherein the two rollers are disposed at positions different from each other by 180 degrees around a rotation center of a rotation shaft connected to the motor. The ink jet recording apparatus according to claim 1, wherein a position detection sensor is provided on the guide member, and a detected portion is provided on a part of the pressing member. The ink jet recording apparatus according to claim 11, wherein the position detection sensor is a magnet sensor, and the detected portion is a magnet. A tube pump used for feeding a liquid contained in a tube,
An elastic tube, and an arcuate guide member for guiding the tube;
At least one pressing member that presses the tube against the guide member;
An escape portion that allows the tube to escape without being pressed by the pressing member to a part of the guide member;
A tube pump comprising: An elastic tube, and an arcuate guide member for guiding the tube;
At least one pressing member that presses the tube against the guide member;
An escape portion that allows the tube to escape without being pressed by the pressing member to a part of the guide member;
A liquid feeding method for feeding a liquid to a liquid ejecting head that discharges liquid from a recording means and records on a recording material using a tube pump comprising:
A pressing liquid feeding step in which the pressing member rotates while pressing the tube;
A pressing release step for stopping the pressing member at the escape portion;
A liquid feeding method comprising:

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