JP5668783B2 - Inkjet recording device - Google Patents

Description

  The present invention relates to an ink jet recording apparatus.

2. Description of the Related Art Conventionally, an ink jet printer has been proposed and put into practical use as an image recording apparatus capable of recording an image on various recording media such as plain paper and plastic thin plate. The ink jet printer includes an ink jet head having an ink ejection port for ejecting ink. By ejecting ink as fine droplets from the ink ejection port of the ink jet head toward the recording medium, a predetermined amount is applied to the recording medium. An image is recorded. The ink jet head is fixedly mounted on a head folder of the printer main body.
In such an ink jet printer, it is known to attach a baffle plate to the head folder in order to weaken the wind that occurs during operation of the ink jet head or the like (see, for example, Patent Documents 1 and 2). It is also known that if there is a convex portion around the ink jet head, an upstream air flow is generated at the back of the convex portion during operation or the like (see, for example, Patent Documents 3 and 4).

JP 2000-108330 A JP 2004-174401 A JP-A-2005-114506 JP 2005-053067 A

By the way, the landing position of droplets is shifted by the air flow between the nozzle of the inkjet head and the recording medium, the amount of micro-droplets called satellites increases, and the satellites adhere to unexpected positions. It may affect the discharge of droplets. As a result, the quality of the printed matter may be deteriorated, and dirt may be generated inside the ink jet head or the printer due to floating of satellite droplets.
When the current plate is attached as in Patent Documents 1 and 2, turbulence may occur on the back surface of the current plate due to the current plate. Also, turbulence is likely to occur even when the nozzle surface and the head folder surface are not the same surface. For this reason, it is more affected by the discharge of the droplets, and the satellite droplets are liable to float, which worsens the above problem.
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an ink jet recording apparatus capable of suppressing the generation of turbulence and improving the printing quality.

In order to solve the above problems, the invention of claim 1 includes a recording head having a plurality of nozzles and ejecting ink onto a recording medium facing the plurality of nozzles;
In an inkjet recording apparatus that ejects ink from the plurality of nozzles to the recording medium while relatively moving the recording head and the recording medium,
The recording head is mounted on a head folder,
A convex body projecting from the facing surface to the recording medium side is provided on the facing surface of the head folder facing the recording medium and upstream of the recording head in the relative movement direction,
The convex body is longer than the tip of the recording head and has a plurality of vent holes through which an air flow passes during the relative movement .

The invention of claim 2 is the ink jet recording apparatus according to claim 1,
The opening ratio of the convex body is 10% or more and 90% or less.

The invention of claim 3 is the ink jet recording apparatus according to claim 1 or 2,
The convex body is further provided downstream of the recording head in the relative movement direction on the facing surface of the head folder facing the recording medium.

Invention of Claim 4 is an inkjet recording device as described in any one of Claims 1-3,
The plurality of vent holes are formed at the tip of the convex body on the recording medium side.

Invention of Claim 5 is an inkjet recording device as described in any one of Claims 1-3,
The plurality of vent holes are formed in the entire convex body.

The invention of claim 6 is the ink jet recording apparatus according to claim 5,
The vent hole formed at the base end on the head folder side of the convex body has a larger diameter than the vent hole formed at the tip end on the recording medium side.

The invention of claim 7 is the ink jet recording apparatus according to any one of claims 1 to 3,
The plurality of vent holes are formed at a base end of the convex body on the head folder side.

The invention of claim 8 is the ink jet recording apparatus according to any one of claims 1 to 7,
A plurality of the convex bodies are provided on the facing surface of the head folder facing the recording medium.

The invention of claim 9 is the ink jet recording apparatus according to claim 8,
Among the plurality of convex bodies, the diameter of the vent hole of the outer convex body located on the upstream side and the downstream side in the relative movement direction is larger on the inner side located on the midstream side than the outer convex body. It is smaller than the diameter of the vent hole of the convex body.

Invention of Claim 10 is an inkjet recording apparatus as described in any one of Claims 1-9.
The convex body is a metal plate.
The invention of claim 11 is the inkjet recording apparatus according to any one of claims 1 to 10,
The plurality of vent holes are filled with air.
The invention of claim 12 is the inkjet recording apparatus according to any one of claims 1 to 11,
A plurality of the recording heads arranged in the relative movement direction are mounted on the head folder,
The convex body is a facing surface of the head folder facing the recording medium, and is provided on the upstream side of the plurality of recording heads in the relative movement direction and protruding from the facing surface to the recording medium side. It is characterized by being.

  According to the present invention, the air flow generated during the relative movement of the head folder passes through the numerous holes. Therefore, generation | occurrence | production of turbulences, such as an updraft in the back part of a convex body, can be suppressed. As a result, it is possible to prevent the occurrence of erroneous ink landing and the occurrence of ink landing distribution, thereby improving the printing quality.

1 is a schematic configuration diagram illustrating an entire inkjet recording apparatus according to an embodiment of the present invention. (a)-(b) is the figure which showed typically the attachment state of a recording head, a head folder, and a baffle plate. (a)-(e) is for demonstrating other embodiment, and is the figure which showed typically the attachment state of a recording head, a head folder, and a baffle plate. 1 is a top view of a line head type inkjet recording apparatus 200. FIG.

  Hereinafter, embodiments of an ink jet recording apparatus according to the present invention will be described with reference to the drawings. However, the present invention is not limited to the illustrated example.

[First Embodiment]
First, the configuration of an inkjet recording apparatus 100 according to an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a schematic configuration diagram showing an entire inkjet recording apparatus 100 according to an embodiment of the present invention.

  As shown in FIG. 1, the ink jet recording apparatus 100 is a serial head type ink jet recording apparatus, and includes an apparatus main body 1. A platen 2 that supports the recording medium 8 from the non-recording surface side is disposed in the apparatus main body 1 so as to extend in the longitudinal direction of the apparatus main body 1. The area where the platen 2 is provided is a recording area for image recording, and the recording medium 8 is conveyed on the platen 2 in the sub-scanning direction Y, which is a predetermined conveying direction, by a conveying mechanism (not shown). ing.

  A rod-shaped guide rail 3 extending in the longitudinal direction of the apparatus main body 1 is provided above the platen 2 and upstream of the recording medium 8 in the sub-scanning direction Y. A head folder 4 is supported on the guide rail 3. The head folder 4 reciprocates along the guide rail 3 in the main scanning direction X orthogonal to the sub-scanning direction Y by a moving mechanism (not shown). In the following description, the case where the head folder 4 is moved in the right direction in the main scanning direction X in FIG.

In the head folder 4, ink is supplied from the ink tank 6 of each color (for example, yellow (Y), magenta (M), cyan (C), and black (K)) used in the ink jet recording apparatus 100 to the recording medium 8. A recording head 5 is mounted. Each color ink tank 6 and the corresponding recording head 5 are connected.
Note that the ink used in the inkjet recording apparatus 100 is not limited to the exemplified ones. For example, light yellow (LY), light magenta (LM), light cyan (LC), and other color inks such as white ink and transparent ink. Can also be used. In this case, the recording head 5 corresponding to each color is mounted on the head folder 4. Further, the number of recording heads 5 is not limited to the one exemplified here, and a larger number of recording heads 5 may be mounted on the head folder 4.

  Inside the recording head 5, a plurality of nozzles that eject ink (not shown) are provided in a row along the sub-scanning direction Y. An ink discharge port is formed.

  For example, a piezo element (not shown) as a piezoelectric element that is deformed by applying a voltage as an actuator is attached to the nozzle of each recording head 5. By applying a driving voltage to the piezo element, the piezo element is deformed, an ink flow path (not shown) is compressed, and ink is ejected from the ink ejection port of the nozzle. Note that ink is drawn inside the nozzle at the tip of the nozzle to form a curved surface shape (meniscus), and normal ink discharge can be performed if the meniscus shape is properly adjusted. It can be done.

FIG. 2 is a diagram schematically showing how the recording heads 5, the head folder 4, and the current plate 7 are attached.
The bottom surface of the head folder 4 is composed of a support plate 40, and each recording head 5 is supported on the support plate 40.
The bottom surface 51 of each recording head 5 is preferably mounted so as to be substantially flush with the bottom surface 41 of the support plate 40. However, as shown in FIG. 2 (a), the bottom surface 51 of the recording head 5 is slightly supported. The bottom plate 41 may protrude downward from the bottom surface 41 of the plate 40, or the bottom plate 41 of the support plate 40 may be mounted in a state where it is recessed from the bottom surface 51 of the recording head 5 as shown in FIG. good.
A rectifying plate (convex body) 7 projecting downward is attached to an upstream end portion in the main scanning direction X on the bottom surface 41 of the support plate 40. The rectifying plate 7 protrudes downward from the lower end (tip) of the recording head 5 and has a mesh structure in which a large number of fine holes 71 are formed. A large number of holes 71 are formed substantially uniformly throughout the current plate 7.

The opening ratio of the rectifying plate 7 is 10% or more and 90% or less. When the aperture ratio is less than 10%, the aperture ratio is too small to allow air to pass through and it is difficult to suppress the generation of turbulent airflow. When it exceeds 90%, air easily passes and the airflow is weak. This is because it must not.
The diameter of the fine hole 71 is preferably 5 μm or more and 100 μm or less. If it is less than 5 μm, the hole 71 is too small to allow air to pass, and if it exceeds 100 μm, the hole 71 is too large to weaken the air flow.
The material of the current plate 7 may be a metal or a resin. In the case of using a metal, the pattern can be easily changed by etching for the formation of many holes 71.

As described above, the recording head 5 of each color having a plurality of nozzles and the head folder 4 are provided, and the bottom surface 41 of the support plate 40 facing the recording medium 8 is positioned at the upstream end in the main scanning direction X at the bottom surface. The rectifying plate 7 projecting from 41 to the recording medium 8 side is longer than the tip of the recording head 5 and has a number of holes 71 and has a mesh structure. Therefore, the air flow generated during the main scanning of the head folder 4 passes through the many holes 71. Therefore, generation | occurrence | production of turbulences, such as an updraft, in the back part (downstream side) of the baffle plate 7 can be suppressed. As a result, ink landing and ink landing distribution can be prevented, and the print quality is excellent.
Moreover, since many holes 71 are formed in the whole baffle plate 7, an air flow can be weakened in the whole baffle plate 7. FIG. In this respect as well, the generation of turbulent airflow at the back of the current plate 7 can be suppressed.

[Second Embodiment]
In FIG. 3A, the rectifying plate 7A having the mesh structure described above is attached to both the upstream end and the downstream end in the main scanning direction X on the bottom surface 41 of the support plate 40, respectively.
Thus, by providing the rectifying plate 7A at both ends of the bottom surface 41 of the support plate 40, the air flow that has passed through the numerous holes 71A of the rectifying plate 7A provided at the upstream end is further changed in the main scanning direction X. The passage of the large number of holes 71A in the rectifying plate 7A at the downstream end of the turbulent air flow can reliably suppress the generation of turbulence.

[Third Embodiment]
In FIG. 3B, a large number of holes 71B formed in the rectifying plate 7B are formed in the distal end portion 7b on the recording medium 8 side of the rectifying plate 7B, and are formed in the base end portion 7a on the head folder 4 side. It has not been. In this case, the speed difference between the airflow passing through the numerous holes 71B formed in the tip 7b of the rectifying plate 7B and the airflow flowing between the rectifying plate 7B and the recording medium 8 is reduced. As a result, turbulence is less likely to occur.
Further, as shown in FIG. 3C, a large number of holes 71C may be formed in the base end portion 7a of the rectifying plate 7C. In this way, by forming the base end portion 7a of the rectifying plate 7B in a mesh structure, a downward airflow is generated from the base end portion 7a of the rectifying plate 7B toward the tip end portion 7b, and thus the generation of the upward airflow can be suppressed. it can.

[Fourth Embodiment]
In FIG. 3D, a large number of holes 71D and 72D formed in the rectifying plate 7D are formed in the entire rectifying plate 7D, and the diameter of the hole 71D on the base end portion 7a side is the hole on the tip end portion 7b side. It is larger than the diameter of 72D. Here, the hole diameter may be gradually increased from the distal end portion 7b side to the proximal end portion 7a side, or the hole size may be increased stepwise. May be.
In this way, by making the diameter of the hole 71D on the base end 7a side of the rectifying plate 7D larger than the diameter of the hole 72D on the tip end 7b side, the base end 7a of the rectifying plate 7D is directed toward the tip 7b. Since downward airflow is generated, generation of upward airflow can be suppressed.

[Fifth Embodiment]
In FIG. 3 (e), rectifying plates 7E and 7E are attached to both ends of the bottom surface 41 of the support plate 40, respectively, and two rectifying plates 7F and 7F are also attached to the inside of these rectifying plates 7E and 7E. ing. In this case, the diameter of the hole 71E of the rectifying plate 7E attached to both ends of the bottom surface 41 of the support plate 40 is smaller than the diameter of the hole 71F of the inner rectifying plate 7F.
Thus, by providing a plurality of rectifying plates 7E and 7F on both ends of the bottom surface of the support plate 40 and on the inside thereof, the speed of the air flow can be reliably reduced and the generation of turbulence can be reliably suppressed.
Further, by making the diameter of the hole 71E of the rectifying plate 7E at both ends of the bottom surface 41 of the support plate 40 smaller than the diameter of the hole 71F of the inner rectifying plate 7F, first, the rectification on the upstream side in the main scanning direction X is performed. The airflow can be rapidly reduced by the plate 7E, and then the velocity can be gradually reduced by the inner rectifying plate 7F and the downstream rectifying plate 7E. As a result, turbulence on the inner recording head 5 side hardly occurs.
Further, the number and arrangement of the rectifying plates 7E and 7F are not limited to those described above, and may be changed as appropriate.

In addition, this invention is not limited to the said embodiment, In the range which does not deviate from the summary, it can change suitably.
For example, the inkjet recording apparatus 100 has been described in the case of the serial method in which the head folder 4 on which the recording head 5 is mounted moves in the main scanning direction X and the recording medium 8 also moves in the sub-scanning direction Y. The present invention may also be applied to a line head system in which the recording medium 8 is fixed and moved.
FIG. 4 is a top view of the line head type ink jet recording apparatus 200. As shown in FIG. 4, a platen 202 that supports the non-recording surface of the recording medium 201 is provided on the bottom surface of the recording medium 201. Conveying rollers 203 a and 203 b for conveying the recording medium 201 are installed on the upstream and downstream sides in the conveying direction Z of the platen 202. The transport rollers 203a and 203b are coupled by a transport belt 203c, and the recording medium 201 is transported along the transport direction Z as the transport rollers 203a and 203b rotate.
Above the platen 202, a head folder 204 including line heads 205, 206, 207, and 208 for each color that forms an image on the recording surface of the recording medium 201 is disposed. The line heads 205, 206, 207, 208 are arranged from the upstream side to the downstream side in the transport direction Z, respectively. Each of the line heads 205, 206, 207, and 208 is a recording head that extends along the width direction of the recording medium 201 orthogonal to the transport direction Z. On the bottom surface (support plate) of such a head folder 204, a rectifying plate 7 similar to that of the first embodiment is provided toward the recording medium 201 side. The rectifying plate 7 is longer than the tips of the line heads 205, 206, 207, and 208, and has a large number of holes (not shown). In FIG. 4, reference numeral 209 denotes a line sensor as an image position detection device that can detect the position of an image formed on the recording medium 201 from the line heads 205, 206, 207, and 208 over the entire width.
The rectifying plates of the second to fifth embodiments can also be applied to the line head system.

4 Head folder 5 Recording head 7, 7A, 7B, 7C, 7D, 7E, 7F Current plate (convex body)
7a Base end portion 7b Front end portion 8 Recording medium 40 Support plates 71, 71A, 71B, 71C, 71D, 72D, 71E, 71F Hole 100 Inkjet recording apparatus X Main scanning direction Y Sub scanning direction

Claims (12)

A recording head having a plurality of nozzles and discharging ink to a recording medium facing the plurality of nozzles;
In an inkjet recording apparatus that ejects ink from the plurality of nozzles to the recording medium while relatively moving the recording head and the recording medium,
The recording head is mounted on a head folder,
A convex body projecting from the facing surface to the recording medium side is provided on the facing surface of the head folder facing the recording medium and upstream of the recording head in the relative movement direction,
The ink jet recording apparatus, wherein the convex body is longer than a tip of the recording head and has a plurality of air holes through which an air flow passes during the relative movement .   2. The ink jet recording apparatus according to claim 1, wherein an aperture ratio of the convex body is 10% or more and 90% or less.   3. The convex body is further provided on the opposite surface of the head folder facing the recording medium on the downstream side of the recording head in the relative movement direction. Inkjet recording apparatus. The inkjet recording apparatus according to any one of claims 1 to 3, wherein the plurality of vent holes are formed at a tip of the convex body on the recording medium side. The inkjet recording apparatus according to claim 1, wherein the plurality of ventilation holes are formed in the entire convex body. 6. The ink jet recording according to claim 5, wherein a vent hole formed at a base end of the convex body on the head folder side has a larger diameter than a vent hole formed at a tip end on the recording medium side. apparatus. The inkjet recording apparatus according to claim 1, wherein the plurality of ventilation holes are formed at a proximal end of the convex body on the head folder side.   The inkjet recording apparatus according to claim 1, wherein a plurality of the convex bodies are provided on the facing surface of the head folder that faces the recording medium. Among the plurality of convex bodies, the diameter of the vent hole of the outer convex body located on the upstream side and the downstream side in the relative movement direction is larger on the inner side located on the midstream side than the outer convex body. The inkjet recording apparatus according to claim 8, wherein the diameter is smaller than the diameter of the vent hole of the convex body.   The inkjet recording apparatus according to claim 1, wherein the convex body is a metal plate. The inkjet recording apparatus according to claim 1, wherein the plurality of ventilation holes are filled with air. A plurality of the recording heads arranged in the relative movement direction are mounted on the head folder,
The convex body is a facing surface of the head folder facing the recording medium, and is provided on the upstream side of the plurality of recording heads in the relative movement direction and protruding from the facing surface to the recording medium side. The ink jet recording apparatus according to claim 1, wherein the ink jet recording apparatus is provided.

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