JP2012236334A - Liquid ejection device, and inkjet recording device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid ejection device capable of stably supplying liquid to a liquid ejection part without increasing a water head difference between a liquid reservoir part and the liquid ejection part.SOLUTION: This liquid ejection device 10 includes: a liquid ejection part 22 ejecting liquid to a medium; a liquid reservoir part 17 storing the liquid; and a first liquid flow path 31 connected so that liquid may flow between the liquid reservoir part 17 and the liquid ejection part 22. The first liquid flow path 31 is provided with a distribution pump 37 distributing the liquid. A first branch part 34 and a second branch part 35 are provided upstream and downstream of the distribution pump 37, respectively. The liquid ejection device further includes a second liquid flow path 32 connected to the first branch part 34 and the second branch part 35 in a manner allowing the liquid to communicate therethrough. The second liquid flow path 32 is provided with a first on-off valve 36 opened at a predetermined pressure or more.

Description

  The present invention relates to a liquid ejecting apparatus and an ink jet recording apparatus, and more specifically, a liquid ejecting apparatus including a liquid ejecting unit that ejects liquid onto a medium, and an ink jet recording apparatus including a recording head that ejects ink onto a recording medium. About.

  An example of the liquid ejecting apparatus is an ink jet printer (ink jet recording apparatus), and various configurations have been conventionally known. For example, a configuration is known in which a platen for supporting a sheet-like recording medium, which is an object to be printed, and a recording head facing the platen are provided above the platen. The recording head is provided for each color such as magenta (M), yellow (Y), cyan (C), and black (K), for example, and a large number of ejection nozzles are formed on the surface facing the platen. Yes. The ink ejected from the ejection nozzle is supplied from the ink cartridge to the recording head. In the liquid ejection apparatus having this configuration, the recording medium supported by the platen while performing the operation of reciprocating the recording head left and right and the operation of relatively moving the recording medium in the front-rear direction orthogonal thereto. Control is performed to eject ink (ink droplets) from the ejection nozzle toward the surface, and desired printing is performed on the surface of the recording medium.

  As a conventional example of the ink jet printer exemplified in the above configuration, as shown in FIG. 3, an ink jet recording head 101, an ink tank 103 for storing ink, a first flow path 109 connecting them, and a first flow path 109 The second flow path 107 branched from the middle of the flow path and connected to the ink tank, the pump 104 attached between the branch point of the flow path and the ink tank, and means for regulating the ink to the first flow path 109 The ink jet printer 100 that blocks the ink flow to the first flow path by the three-way valve 105 as the control means, circulates the ink in the second flow path and the ink tank 103, and stirs the ink in the ink tank 103. Is known (see Patent Document 1).

Japanese Patent No. 3127581

  By the way, in the ink jet printer exemplified in Patent Document 1, for example, in a model using a high-viscosity ink with a small water head difference between the ink storage unit and the ink discharge unit, printing with a high printing speed or both is performed. When printing that consumes a large amount of ink, such as directional printing, is performed, there is a problem that ink supply to the ink ejection unit tends to be insufficient.

  The present invention has been made in view of the above problems, and circulates liquid while stably supplying liquid to the liquid discharge section without increasing the water head difference between the liquid storage section and the liquid discharge section. An object of the present invention is to provide a liquid ejection device that can perform the above operation.

  As an embodiment, the above-described problem is solved by a solution as disclosed below.

  The disclosed liquid ejecting apparatus includes a liquid ejecting unit that ejects liquid onto a medium, a liquid storing unit that stores the liquid ejected from the liquid ejecting unit, and the liquid storing unit between the liquid storing unit and the liquid ejecting unit. And a first liquid channel connected to be able to circulate, wherein the first liquid channel is provided with a flow pump for circulating the liquid, and the flow pump A first branch part is provided on the upstream side and a second branch part is provided on the downstream side with respect to each other. The first branch part and the second branch part are connected to each other so that the liquid can flow therethrough. A second liquid channel is further provided, and the second liquid channel is provided with a first on-off valve that opens at a predetermined pressure or higher. According to this, the liquid can be circulated (circulated) to prevent sedimentation of solids in the liquid, and the liquid can be stably supplied to the liquid discharge unit without increasing the water head difference between the liquid storage unit and the liquid discharge unit. The liquid can be refluxed (circulated) while being supplied.

  In the present invention, the first liquid channel may be provided with a second opening / closing valve that opens at a predetermined pressure or less between the second branch portion and the liquid discharge portion. preferable. According to this, since it is possible to use a circulation pump having a large capacity, it is possible to enhance the liquid reflux (circulation) action and the circulation action.

  The disclosed ink jet printer includes a recording head that ejects ink onto a recording medium, an ink cartridge that stores the ink ejected from the recording head, and the ink cartridge and the recording head that are connected so that the ink can flow. In the ink jet recording apparatus provided with the first liquid flow path, the first liquid flow path is provided with a flow pump for flowing the ink, and on the upstream side with the flow pump interposed therebetween. And a second branch portion provided downstream of the first branch portion and connected to the first branch portion and the second branch portion, respectively. The second liquid channel is further provided with a first on-off valve that opens at a predetermined pressure or higher. According to this, it is possible to prevent the ink coloring material from settling by circulating (circulating) the ink, and to stably supply the ink to the recording head without increasing the water head difference between the ink cartridge and the recording head. However, the ink can be circulated (circulated).

  According to the disclosed liquid ejection device, it is possible to circulate the liquid while stably supplying the liquid to the liquid ejection section without increasing the water head difference between the liquid storage section and the liquid ejection section.

It is the schematic which shows the example of the liquid discharge apparatus which concerns on this embodiment of this invention. FIG. 2 is a schematic diagram of a liquid flow path and its peripheral configuration in the liquid ejection apparatus of FIG. 1. It is the schematic which shows the example of the liquid discharge apparatus which concerns on the conventional embodiment.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Here, the case of an inkjet printer will be described as an example of the liquid ejection apparatus according to the present embodiment. Note that components having the same function are denoted by the same reference symbols throughout the drawings for describing the embodiments, and the repetitive description thereof may be omitted.

  FIG. 1 shows a configuration of a liquid ejection apparatus (here, an ink jet printer) 10 according to the present embodiment. For convenience of explanation, the left and right and up and down directions of the ink jet printer 10 are indicated by the arrow directions in FIG. Further, the front-rear direction of the paper surface in FIG. Hereinafter, description will be made using these directions.

  As shown in FIG. 1, the ink jet printer 10 is provided with a central body portion 12 supported by support legs 11, a left body portion 13 provided on the left side of the central body portion 12, and a right side of the central body portion 12. The right body portion 14 and the left and right body portions 13 and 14 are connected to each other, and the upper body portion 15 that extends in parallel is spaced apart above the central body portion 12. In the inkjet printer 10, the operation of each part is controlled by a control unit 40 provided inside the left body part 13.

  A guide rail 15a extending left and right is provided inside the upper body portion 15, and the head unit 20 is attached to the guide rail 15a. The head unit 20 includes a carriage 21 that is attached to the guide rail 15 a and is movable left and right, and a recording head 22 mounted on the carriage 21. As an example, the recording head 22 discharges a black head 22K that discharges black ink, a magenta head 22M that discharges magenta ink, a yellow head 22Y that discharges yellow ink, a cyan head 22C that discharges cyan ink, and a white ink. The white head 22 </ b> W is configured to be mounted on the carriage 21. A plurality of ejection nozzles (not shown) for ejecting ink downward toward the recording medium M are formed on the lower surface of the recording head 22. For example, a nozzle row formed by linearly arranging 180 discharge nozzles in the front-rear direction is formed by arranging 8 rows in the left-right direction. Ink ejection control at each ejection nozzle is performed by a drive control signal output from the control unit 40 to each recording head 22.

  A flat platen 12a extending left and right is exposed on the upper surface of the central body portion 12, and a feed roller (not shown) extending left and right is exposed on the rear side of the platen 12a. Yes. The feed roller is rotationally driven by a front / rear drive motor 19 provided inside the central body portion 12. For this reason, the drive control signal from the control unit 40 in a state where the sheet-like recording medium M to be printed is sandwiched between a pinch roller (not shown) provided in the upper body portion 15 and a feed roller. Accordingly, the recording medium M can be fed back and forth by a feed amount corresponding to the drive control amount.

  A cartridge mounting portion 16 is provided on the upper portion of the right body portion 14, and a plurality of ink cartridges 17 are inserted into the cartridge mounting portion 16 in the front-rear direction. The plurality of ink cartridges 17 are connected to the recording head 22 via an ink flow path to be described later. The ink in the ink cartridge 17 is supplied to the recording head 22 through the ink flow path according to the ink consumption in the recording head 22. In addition, a right and left drive motor 29 for moving the head unit 20 left and right along the guide rail 15a is provided inside the right body portion 14. By driving the left / right drive motor 29 in accordance with a drive control signal from the control unit 40, the left / right drive motor 29 can be moved left and right by a feed amount corresponding to the drive control amount.

  On the front side of the left body portion 13, an operation display portion 13 a configured from operation switches, display devices, and the like is provided. A maintenance unit 30 and a control unit 40 are provided inside the left body portion 13. The maintenance unit 30 is detachably attached to the recording head 22 and is formed according to the shape of the bottom surface of the recording head 22 and opened upward, and a discharge pump (see FIG. And a cap drive motor 39. By driving the cap drive motor 39 in accordance with a drive control signal from the control unit 40, the cap drive motor 39 can be moved up and down by a movement amount corresponding to the drive control amount. Moreover, a negative pressure can be applied to the inside of the cap member by driving the discharge pump.

  The control unit 40 temporarily stores a ROM (Read-Only Memory) (not shown) in which a control program for controlling the operation of each unit of the inkjet printer 10 is written, a program for printing on the recording medium M, and the like. A RAM (Random Access Memory) (not shown), a control unit 41 that performs arithmetic processing on a program read from the RAM, an operation signal input from the operation display unit 13a, and the like, and controls the operation of each unit according to the control program. (See FIG. 2). The control unit 40 sends drive control signals to the flow pump 37 (see FIG. 2), the front / rear drive motor 19, the left / right drive motor 29, the cap drive motor 39, the recording head 22, and the like based on the calculation processing result in the control unit 41. These operations are controlled by outputting.

  Here, a characteristic ink flow path and a peripheral configuration in the liquid ejection apparatus according to the present embodiment will be described in detail.

FIG. 2 is a schematic view of an ink flow path and its peripheral configuration in the liquid ejection apparatus (here, an ink jet printer) 10 according to the present embodiment.
As shown in FIG. 2, the inkjet printer 10 includes a first in which ink is circulated between a liquid storage unit (here, an ink cartridge) 17 and a liquid ejection unit (here, a recording head) 22. The liquid flow path 31 is provided.

  A flow pump 37 is provided in the middle of the first liquid channel 31. The flow pump 37 is a drive source that circulates ink in the first liquid flow path 31 and the second liquid flow path 32 described later. As an example of the flow pump 37, it is conceivable to use a tube pump or the like, but the present invention is not limited to this.

  Further, in the middle of the flow path of the first liquid flow path 31, a first branch part 34 is provided on the upstream side with the flow pump 37 interposed therebetween, and a second branch part 35 is provided on the downstream side. That is, the first branch portion 34 is disposed in the middle of the first liquid channel 31 and between the ink cartridge 17 and the circulation pump 37, and the second branch portion 35 includes the first branch portion 35. In the middle of the liquid flow path 31, the liquid flow path 31 is disposed between the flow pump 37 and the recording head 22.

As shown in FIG. 2, the inkjet printer 10 includes a second liquid flow path 32 that is connected to the first branch portion 34 and the second branch portion 35 and communicates with the ink so that it can flow therethrough. .
Here, the second liquid channel 32 is provided with a first on-off valve 36 that opens at a predetermined pressure or higher.

  In the present embodiment, a pressure damper unit 60 is provided in the middle of the first liquid channel 31 and between the second branch portion 35 and the recording head 22. As an example, the pressure damper unit 60 includes a filter chamber 61 for removing foreign matter in the ink, and a sealing valve (second open / close valve) 62 that automatically opens when the pressure in the pressure chamber 63 becomes a certain level or less. It is configured with. According to this, when the pressure in the pressure chamber 63 decreases due to the discharge of ink from the discharge nozzle (not shown) of the recording head 22, the second opening / closing valve 62 is opened, so the first Ink flows from the flow path 31 to the recording head 22 and is replenished.

  Further, in the present embodiment, the effects described later can be obtained, so that the pressure damper unit 60 can be arranged so that the water head difference is small with respect to the ink cartridge 17.

As described above, the present invention (1) stably supplies ink with a constant positive pressure toward the recording head 22 during printing. (2) Further, during printing, ink is circulated to the recording head 22 side at a positive pressure equal to or higher than the predetermined pressure. It aims at two. Therefore, in particular, the following characteristic configuration is provided.
(A) A flow pump 37 is disposed between the flow paths of the ink cartridge 17 and the recording head 22.
(B) It has two branch parts (first branch part 34, second branch part 35) arranged so as to sandwich the flow pump 37, and these two branch parts (first branch part 34, A circulation path (second liquid flow path 32) connected to the second branch part 35);
(C) A pressure valve (first opening / closing valve 36) is provided in the circulation path (second liquid flow path 32).

  Therefore, if the circulation pump 37 is disposed in the circulation path (second liquid flow path 32), the above two objects (1) and (2) cannot be achieved. On the other hand, the present invention makes it possible to achieve the two objects simultaneously by providing the above-described characteristic configuration. That is, by setting the ink pressure to be equal to or higher than the predetermined pressure during printing, it is possible to perform stable printing even when ink circulation is performed in the circulation path (second liquid flow path 32).

  The configuration of the inkjet printer 10 has been described above as an example of the liquid ejection device. Here, the operation of the inkjet printer 10 will be described along the flow of ink inside the apparatus.

  First, the distribution pump 37 is activated. As a result, ink is taken into the flow pump 37 from the first flow path 31 upstream of the flow pump 37, and the ink is flowed into the first flow path 31 downstream of the flow pump 37. The action sent out from 37 occurs. Therefore, the ink stored in the ink cartridge 17 flows in the first flow path 31 toward the pressure damper unit 60.

  At this time, if printing by the recording head 22 is not performed, ink is not ejected from an ejection nozzle (not shown) of the recording head 22, and the pressure in the pressure chamber 63 is equal to or less than a predetermined value (predetermined opening setting value). Therefore, the second opening / closing valve 62 is kept closed. As a result, the pressure in the first flow path 31 on the upstream side of the second opening / closing valve 62 (specifically, between the flow pump 37 and the second opening / closing valve 62) increases.

  Here, when the pressure in the first flow path 31 between the flow pump 37 and the second on-off valve 62 rises, the pressure is connected to the second branch portion 35 and branched from the first flow path 31. The pressure in the second flow path 32 (specifically, between the second branch portion 35 and the first opening / closing valve 36) increases. As a result, when the pressure acting on the first opening / closing valve 36 increases to a predetermined value (predetermined opening setting value) or more, the first opening / closing valve 36 is opened. As a result, ink flows from the first flow path 31 into the second flow path 32 via the second branch portion 35. The ink further passes through the first opening / closing valve 36 and circulates in the second flow path 32 toward the first branch portion 34. Furthermore, the fluid flows from the first branch portion 34 into the first flow path 31 and is again taken into the flow pump 37, thereby causing the ink to return. As described above, by obtaining the action of circulating (circulating) the ink, it is possible to prevent sedimentation of the color material contained in the ink.

  On the other hand, when printing by the recording head 22 is performed, the pressure in the pressure chamber 63 falls below a predetermined value (predetermined opening setting value) by discharging ink from an ejection nozzle (not shown) of the recording head 22. It falls and the 2nd opening-and-closing valve 62 will be in an open state. As a result, ink flows from the first flow path 31 to the recording head 22 to be replenished. At this time, the pressure in the first flow path 31 on the upstream side of the second opening / closing valve 62 (specifically, between the flow pump 37 and the second opening / closing valve 62) decreases.

Here, when the pressure in the first flow path 31 between the flow pump 37 and the second opening / closing valve 62 decreases, the pressure is connected to the second branch portion 35 and branches from the first flow path 31. The pressure in the second flow path 32 (specifically, between the second branch portion 35 and the first on-off valve 36) is lowered. As a result, the pressure acting on the first opening / closing valve 36 decreases below a predetermined value (predetermined opening setting value), and the first opening / closing valve 36 is closed. As a result, the ink flow from the first flow path 31 to the second flow path 32 via the second branch portion 35 is stopped. For this reason, an action of increasing the pressure in the first flow path 31 between the flow pump 37 and the second opening / closing valve 62 occurs.
That is, even when a large water head difference between the ink cartridge 17 and the pressure damper unit 60 is not provided, a predetermined pressure (of the first opening / closing valve 36) when printing by the recording head 22 is started by the activation of the flow pump 37. An appropriate positive pressure can be applied to the pressure damper unit 60 at a value less than the opening setting value. In this case, the flow pump 37 is controlled to an appropriate driving state by the control unit 41.

  As described above, since the pressure applied to the pressure damper unit 60 can be maintained at an appropriate positive pressure, a necessary ink flow rate corresponding to the ink consumption amount in the recording head 22 at the time of printing can be ensured. Therefore, for example, in a model that uses ink having a small water head difference between the ink cartridge and the pressure damper unit (or recording head) and using high viscosity ink, the ink consumption for printing at high printing speed or bidirectional printing, etc. When printing with a large amount of printing is performed, the problem that ink supply to the recording head tends to be insufficient can be solved. That is, it is possible to prevent a situation in which the ink supply amount becomes insufficient (insufficient) with respect to the ink consumption amount in the recording head 22.

  As described above, according to the disclosed liquid ejection device, the liquid is circulated (circulated) while stably supplying the liquid to the liquid ejection unit without increasing the water head difference between the liquid storage unit and the liquid ejection unit. It becomes possible to make it. Moreover, it becomes possible to prevent sedimentation of the solid contained in the liquid by the reflux (circulation) of the liquid. In particular, according to the present embodiment, the following characteristic effects are exhibited.

  The ink jet printer 10 includes a recording head 22 that ejects ink onto a recording medium M, an ink cartridge 17 that stores ink ejected from the recording head 22, and an ink cartridge 17 and the recording head 22 that are connected so that ink can flow. The first liquid flow path 31 is provided with a flow pump 37 for flowing ink, and the first branch on the upstream side with the flow pump 37 interposed therebetween. A second branch part 35 is provided on each of the first part 34 and the downstream side, and is connected to the first branch part 34 and the second branch part 35, and further has a second liquid channel 32 communicating with the ink in a flowable manner. The second liquid channel 32 is provided with a first opening / closing valve 36 that opens at a predetermined pressure or higher. According to this, even when printing at high printing speed or bidirectional printing is performed, the ink can be circulated (circulated) while stably supplying ink without increasing the water head difference. In addition, by performing the circulation (circulation) of the ink between the first liquid channel 31 that supplies ink and the second liquid channel 32 that circulates the ink, for example, white ink or the like has a large specific gravity. Sedimentation of the ink coloring material can be prevented. Furthermore, since the pressure damper unit 60 is used as compared with the pressure-feed type ink supply method, the negative pressure control of the nozzle surface of the recording head can be easily performed.

  The first liquid channel 31 is provided with a second opening / closing valve 62 that opens between the second branch portion 35 and the recording head 22 at a predetermined pressure or less. According to this, since it is possible to use the circulation pump 37 having a large capacity, it is possible to enhance the reflux (circulation) action and the circulation action of the ink.

  Needless to say, the present invention is not limited to the embodiment described above, and various modifications can be made without departing from the present invention. In particular, the ink jet printer has been described as an example of the liquid ejecting apparatus, but the present invention is not limited to this, and can be applied to other apparatuses.

DESCRIPTION OF SYMBOLS 10 Liquid discharge apparatus 12 Central body part 13 Left body part 14 Right body part 15 Upper body part 16 Cartridge mounting part 17 Ink cartridge 20 Head unit 21 Carriage 22 Recording head 30 Maintenance unit 31 1st liquid flow path 32 2nd liquid Flow path 34 First branch part 35 Second branch part 36 First on-off valve 37 Flow pump 40 Control unit 41 Control part 60 Pressure damper unit 62 Second on-off valve 63 Pressure chamber M Recording medium

Claims (3)

A liquid discharge unit that discharges liquid to a medium, a liquid storage unit that stores the liquid discharged from the liquid discharge unit, and the liquid storage unit and the liquid discharge unit are connected to be able to flow. A liquid ejection apparatus comprising: a first liquid channel;
The first liquid flow path is provided with a flow pump for flowing the liquid, and a first branch portion is provided upstream and a second branch portion is provided downstream of the flow pump. And
A second liquid channel connected to the first branch part and the second branch part, the second liquid channel communicating with the liquid in a flowable manner;
The liquid ejecting apparatus, wherein the second liquid channel is provided with a first on-off valve that opens at a predetermined pressure or higher. 2. The first liquid flow path is provided with a second opening / closing valve that opens at a predetermined pressure or less between the second branch portion and the liquid discharge portion. The liquid discharge apparatus as described. A recording head for discharging ink to a recording medium, an ink cartridge for storing the ink discharged from the recording head, and a first liquid in which the ink is connected between the ink cartridge and the recording head so as to be able to flow therethrough An ink jet recording apparatus comprising a flow path,
The first liquid flow path is provided with a flow pump for flowing the ink, and a first branch portion is provided on the upstream side and a second branch portion is provided on the downstream side of the flow pump. And
A second liquid channel connected to the first branch part and the second branch part, the second liquid channel communicating with the ink in a flowable manner;
The inkjet recording apparatus, wherein the second liquid channel is provided with a first opening / closing valve that opens at a predetermined pressure or higher.

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