JP2004330599A - Ink jet recorder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ink jet recorder in which ink mist can be collected effectively through a small and simple structure without requiring an additional device. <P>SOLUTION: A box type carriage 10 is held on a shaft (not shown) and reciprocated in the arrow direction while keeping a constant interval to a sheet when print operation is performed. An air intake 12 is provided in the surface becoming the head or the rear end when the carriage 10 is reciprocated and air is sucked from the air inlet 12 by traveling wind pressure (ram pressure) being generated as the carriage 10 is reciprocated. The air inlet 12 is connected with an exhaust duct 14 and the sucked air is discharged from an exhaust opening 16. The exhaust duct 14 is coupled with a negative pressure duct 20 extended in the direction of an ink ejection surface 24 through a coupling part 18 and the negative pressure duct 20 is coupled with a mist suction opening 22 provided in the ink ejection surface 24. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an inkjet recording device.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, it has been known that when an ink droplet is ejected from a recording head in an ink jet recording apparatus, it is separated into a relatively large ink droplet called a main droplet and a small droplet called a satellite. Further, fine droplets (ink mist) smaller than the satellite may be formed.
[0003]
Smaller satellites with lower speeds are more susceptible to the effects of the surrounding airflow before they reach the paper from the printhead, and the main droplets reach the print paper and adhere to locations away from the dots where they were formed. Therefore, the image becomes dirty. Or, it may not reach the paper and float inside the recording device to contaminate the inside of the recording device.
[0004]
Further, mist smaller than the satellite does not reach the recording surface, and floats near the paper, and then contaminates the inside of the apparatus and the margins of the recording paper.
[0005]
Therefore, there is disclosed a configuration in which a fan is forcibly generated airflow by a fan during printing, and a part of the floating satellite or mist is collected by a filter or the like (for example, see Patent Document 1).
[0006]
However, the above method requires a space for installing a fan that generates airflow, which leads to an increase in the size of the recording device. In addition, the problem of increased power consumption and noise caused by the fan also occurs. In particular, this is a serious problem for an ink jet printer characterized by its small size, low power consumption, and quietness.
[0007]
Alternatively, an apparatus for collecting mist without newly adding a driving part such as a fan is disclosed (for example, see Patent Document 2). In this method, a mist collecting means is provided on a carriage on which a recording head is mounted and which scans, and an air flow generated by scanning the carriage is used for collecting the mist. It is also disclosed to install a rectifying plate for more effective recovery.
[0008]
However, the device disclosed in Patent Literature 2 does not have a configuration in which the airflow collides with the current plate and the airflow around the current plate is disturbed, so that the mist is further scattered. Further, the configuration is based on the premise that the mist exists in a region very close to the recording head, and that an air flow near the recording head is generated in a direction opposite to the carriage scanning direction.
[0009]
However, the following was found from the results of detailed observations of the flow of airflow around the recording head when the carriage was scanned, the generation of mist, and the floating state when the carriage was scanned.
[0010]
That is, the mist that does not reach the paper separates from the trajectory of the main droplet from a place away from the recording head by a certain distance, depending on the size of the mist and the scanning speed of the carriage, and starts floating, not in a place very close to the recording head. . The airflow generated by the scanning of the carriage is generated in a direction opposite to the scanning direction of the carriage in a region where the main droplet reaches, which is close to the recording paper, but flies toward the recording head downstream in the scanning direction of the carriage, and the recording head discharges. In an area very close to the surface, the direction is the same as the carriage scanning direction.
[0011]
These observations led to the finding that the most effective way to collect the mist near the printhead in some way was to collect the mist that flew toward the printhead downstream in the carriage scanning direction. . That is, a desired effect cannot be obtained with the structure disclosed in Japanese Patent Application Laid-Open No. H11-157572 in which the airflow near the ejection surface of the recording head is introduced indiscriminately. Therefore, a structure for actively sucking the airflow near the recording head ejection surface is required.
[0012]
Further, in recent years, high-speed printing of the ink jet recording apparatus has been advanced, and the frequency (printing frequency) at which ink droplets are repeatedly ejected has been increased. In this case, the amount of mist may be further increased. In addition, the service life of the print head has been prolonged due to the improvement in the reliability of the print head, and the number of ink droplets that can be ejected before the service life of the print head has also increased, resulting in an increase in the total amount of mist generated as a result. In this case, it is necessary to improve the collecting ability of the collecting plate for collecting the mist. However, usually, it is effective to increase the surface area of the collecting plate in contact with the mist to improve the mist collecting ability. However, in the structure disclosed in Patent Literature 2, since the accumulation plate for accumulating mist is provided inside the carriage, the size of the carriage is increased.
[0013]
[Patent Document 1]
JP-A-11-138779 (FIG. 3, page 4 to page 8)
[Patent Document 2]
JP-A-2000-263814 (FIG. 4, page 4 to page 6)
[0014]
[Problems to be solved by the invention]
The present invention has been made in view of the above circumstances, and has as its object to provide an ink jet recording apparatus that effectively collects ink mist with a small and simple structure without adding an additional device.
[0015]
Means for Solving the Invention
The inkjet recording apparatus according to claim 1, comprising: a recording head having a plurality of nozzles for ejecting ink droplets onto recording paper to form an image; and a carriage for holding and moving the recording head. An air intake port provided in the carriage and opened in the moving direction of the carriage; an exhaust duct for exhausting air taken in from the air intake port; and an airflow connected to the exhaust duct and flowing through the exhaust duct. And a mist collecting port formed in the air intake of the negative pressure duct for sucking and collecting ink mist.
[0016]
In the invention having the above configuration, the air mist generated by the movement of the carriage is introduced from the air intake port provided in the carriage, and the ink mist is collected from the mist collection port by using the negative pressure generated when the air is exhausted from the exhaust duct. Can be sucked and collected. Therefore, the mist can be collected more efficiently than a structure in which a mist collecting port is simply provided in the carriage or the recording head, and a simple and compact structure can be achieved without providing an additional device such as an intake fan. it can.
[0017]
An ink jet recording apparatus according to a second aspect is characterized in that one or a plurality of ink mist accumulating means for accumulating the collected ink mist is replaceably provided in an exhaust duct.
[0018]
In the invention having the above configuration, the ink mist collecting means is replaceably provided, so that the collected ink mist is collected so as not to be scattered inside the machine again, and is replaced even if the collecting means becomes saturated with the ink mist. This makes it possible to always integrate.
[0019]
4. The ink jet recording apparatus according to claim 3, further comprising: a counting unit for counting the number of printed pixels; and a notifying unit for notifying the replacement time of the mist accumulating unit based on the accumulated number of pixels from the counting unit. And
[0020]
In the invention having the above configuration, by counting the number of printed pixels, the amount of ink ejected from the accumulated number of pixels, and thus the amount of generated ink mist can be calculated, so that the accumulated amount of mist collected by the mist accumulating means is calculated, The replacement time can be predicted before the mist accumulation means becomes saturated, and the user can be notified.
[0021]
An ink jet recording apparatus according to a fourth aspect is characterized in that the mist accumulating means is provided with a display means for notifying the replacement time of the mist accumulating means.
[0022]
In the invention having the above configuration, the display means for notifying the replacement time is provided to the mist collecting means itself, so that the user can be notified of the replacement time of the mist collecting means without any additional device.
[0023]
BEST MODE FOR CARRYING OUT THE INVENTION
1 and 2 show a carriage of an ink jet recording apparatus according to a first embodiment of the present invention.
[0024]
As shown in FIG. 1, the carriage 10 has a box shape, is held by a shaft (not shown), and reciprocates in a direction indicated by an arrow while maintaining a constant interval with a sheet when a printing operation is performed.
[0025]
When the carriage 10 reciprocates, an air intake port 12 is provided on the front or rear end surface, and air is sucked in from the air intake port 12 by running wind pressure (ram pressure) generated as the carriage 10 reciprocates. I do.
[0026]
The air intake 12 is directly connected to the exhaust duct 14, and the intake air is exhausted from the exhaust port 16.
[0027]
The exhaust duct 14 is connected to a negative pressure duct 20 extending in the direction of the ink discharge surface 24 by a connecting portion 18, and the negative pressure duct 20 is connected to a mist suction port 22 provided on the ink discharge surface 24.
[0028]
The internal structure described above has a rotationally symmetric structure, and when the carriage 10 reciprocates, the two sets of the air intake 12, the exhaust duct 14, and the exhaust An opening 16, a connecting portion 18, a negative pressure duct 20, and a mist inlet 22 are provided.
[0029]
As shown in the three views of FIG. 2, a recording head 28 of the number of ink colors is provided in a gap provided at the center of the carriage 10. The recording head 28 is held by the carriage 10 which reciprocates and ejects ink droplets from the nozzle surface 28A to form an image on a sheet.
[0030]
A filter 26 is detachably provided on the top surface of the carriage 10 so as to cover the exhaust port 16, and ink mist sucked from the mist inlet port 22 through the negative pressure duct 20 does not leak from the outlet port 16. And collect it.
[0031]
FIG. 3 shows the operation principle of the carriage of the ink jet recording apparatus according to the first embodiment of the present invention.
[0032]
As shown in FIG. 3, when the carriage 10 moves in the direction of the oblique arrow (right in the drawing), air flows into the air intake port 12 by the wind pressure into the exhaust duct 14 as indicated by the white arrow, and exits to the exhaust port 16.
[0033]
At this time, the air flow (white arrow) flowing through the exhaust duct 14 creates a negative pressure in the vicinity of the connecting portion 18, so that the inside of the negative pressure duct 20 also has a negative pressure, and a pressure acts in a direction to suck air from the mist inlet 22. .
[0034]
On the other hand, at the same time as the carriage 10 moves in the diagonal arrow direction by the printing operation, ink droplets are ejected from the nozzle surface 28A of the recording head 28 to form an image. At this time, ink mist is generated and floats between the paper surface 30 and the ink ejection surface 24 as indicated by a black arrow.
[0035]
Since the mist suction port 22 is open to the ink discharge surface 24, the ink mist floating near the ink discharge surface 24 due to the negative pressure of the negative pressure duct 20 is sucked from the mist suction port 22 as indicated by a black arrow, and It is carried to the negative pressure duct 20.
[0036]
Since the negative pressure duct 20 joins the exhaust duct 14 at the connecting portion 18, the sucked ink mist also passes through the exhaust duct 14 toward the exhaust port 16.
[0037]
If the ink mist is discharged from the exhaust port 16 as it is, the inside of the machine is contaminated. Therefore, only the ink mist is trapped and collected by the filter 26 provided in the exhaust port 16.
[0038]
Every time the filter 26 traps and collects ink mist, waste ink accumulates inside. Therefore, by replacing the filter after collecting a certain amount of ink mist, it is possible to prevent a reduction in processing capacity.
[0039]
The filter 26 is held by the holder 32, and by replacing the holder 32 at the time of replacement, there is no possibility that the surroundings will be contaminated with ink during the replacement operation.
[0040]
Normally, the total amount of mist generated depends on the number of ejected ink droplets. If the filter 26 does not have the ability to accumulate the total amount of mist generated during the life of the recording head 28, the filter 26 needs to be replaced before the life of the recording head 28. Therefore, it has a means for counting the number of ejected ink droplets (the number of printed pixels), and a means for generating information urging the user to replace the ink droplet when a predetermined count value is reached. Alternatively, if the information is displayed on a PC or the like connected to the ink jet recording apparatus, it is possible to prevent the filter 26 from being replaced and the inside of the machine and the paper surface from being contaminated by ink mist.
[0041]
Further, the filter 26 itself may be formed of a material having a color that makes it easy to visually check the contamination by ink such as white, so that the user can confirm the replacement time of the filter 26 by color. Alternatively, the above two methods may be used simultaneously.
[0042]
FIGS. 4, 5, 6, and 7 show data that is the basis of the operation principle of the carriage of the inkjet recording apparatus according to the first embodiment of the present invention.
[0043]
4 and 5 show the results of observing the airflow between the nozzle surface 28A and the paper surface 30 when the carriage 10 moves during the printing operation.
[0044]
In FIG. 4, the carriage 10 (= recording head 28) is moving at a speed of 0.5 m / s in the direction of the oblique arrow. The distance from the nozzle surface 28A from which the ink droplet 36 is ejected to the paper surface 30 is 1.5 mm.
[0045]
In the figure, white arrows show the outline of the movement of the airflow. FIG. 4 shows that the carriage 10 (= recording head 28) is moving at a speed of 0.5 m / s in the direction of the arrow, and FIG. 5 is moving at a speed of 1 m / s.
[0046]
As described above, due to the movement of the carriage 10, an airflow is generated from the upstream to the downstream (from right to left in the drawing) in the vicinity of the sheet surface 30, but rises from the middle to the direction of the nozzle surface 28A, and In the vicinity of 28A, the flow changes to an upstream direction (from left to right in the figure).
[0047]
6 and 7 show the results of observing the ink mist between the nozzle surface 28A and the paper surface 30 when the carriage 10 moves during the printing operation.
[0048]
The results of observing the ejection state of the ink droplets 36 and the floating state of the mist 38 when the carriage 10 moves during the printing operation using a PIV (Particle Image Velocimetry) for observing the floating state of small particles are shown in FIG. 6 and FIG. 7, in which the carriage 10 (recording head 28) is moving at a speed of 0.5 m / s in the direction of the oblique arrow.
[0049]
The distance from the nozzle surface 28A from which the ink droplet 36 is ejected to the paper surface 30 is 1.5 mm, which is a standard distance in an ink jet printing apparatus. The main droplet group of the ink droplets 36 reaches the paper, but the mist 38 floats from the intermediate position between the nozzle surface and the recording paper from the downstream side to the upstream side in the carriage movement direction. The mist does not float near the nozzle surface 28A but floats near the paper surface 30.
[0050]
FIG. 7 shows a case where the moving speed of the carriage 10 is 1 m / s. The ink mist 38 floats from a substantially intermediate position between the nozzle surface 28A and the paper surface 30 from the downstream side to the upstream side (from right to left in the drawing) in the moving direction of the carriage 10 as in FIG. 6 is closer to the nozzle surface 28A from the sheet surface 30 as compared to FIG. 6 (0.5 m / s).
[0051]
From the above, the ink mist flows in the direction opposite to the recording head 28 (= carriage 10) near the paper surface 30 by riding on the airflow between the nozzle surface 28A and the paper surface 30, and the recording head 28 near the nozzle surface 28A. It can be seen that it flows in the same direction as (= carriage 10).
[0052]
In other words, the height at which the airflow occurs varies depending on the moving speed of the recording head 28, but there is no change in the direction of the airflow. Since the airflow flows near the nozzle surface 28A in the same direction as the recording head 28 (= carriage 10), Even if the mist suction port 22 is provided on the nozzle surface 28A (the ink discharge surface 24), since the carriage 10 and the airflow (ink mist 38) move in the same direction, it is not possible to efficiently collect the ink mist 38. Can not.
[0053]
In the present invention, the mist suction port 22 is provided on the ink discharge surface 24, and the ink mist 38 can be positively sucked and collected by applying a negative pressure to the mist suction port 22.
[0054]
Further, since the mist suction port 22 is provided at the rear end side of the ink discharge surface 24, the ink mist 38 approaching the ink discharge surface 24 by the airflow shown in FIGS. 4 and 5 can be efficiently collected. it can.
[0055]
Further, air inlets 12 are provided on both sides of the carriage 10 in the moving direction, so that when the carriage 10 reciprocates, two sets of air inlets 12 and an exhaust duct are provided so that the air inlets 12 operate equally regardless of which side is the leading side. 14, an exhaust port 16, a connecting portion 18, a negative pressure duct 20, and a mist suction port 22 are provided. As a result, the ink mist 38 is collected by the carriage 10 on the outward path and the return path even during the reciprocating printing operation.
[0056]
【The invention's effect】
Since the present invention has the above-described configuration, it is possible to provide an ink jet recording apparatus that can effectively collect ink mist with a small and simple structure without adding an additional device.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a carriage according to a first embodiment of the present invention.
FIG. 2 is a plan view illustrating a carriage and a recording head according to a first embodiment of the present invention.
FIG. 3 is an explanatory diagram illustrating an operation of the carriage according to the first embodiment of the present invention.
FIG. 4 is a side view showing an airflow between a recording head and a sheet according to the first embodiment of the present invention.
FIG. 5 is a side view showing an air flow between the recording head and a sheet according to the first embodiment of the present invention.
FIG. 6 is a side view showing a mist distribution between a recording head and a sheet according to the first embodiment of the present invention.
FIG. 7 is a side view showing a mist distribution between a recording head and a sheet according to the first embodiment of the present invention.
[Explanation of symbols]
Reference Signs List 10 Carriage 12 Air intake port 14 Exhaust duct 16 Exhaust port 18 Connecting part 20 Negative pressure duct 22 Mist intake port 24 Ink ejection surface 26 Filter 28 Recording head

Claims (4)

A recording head having a plurality of nozzles for ejecting ink droplets on recording paper to form an image,
A carriage for holding and moving the recording head, and an inkjet recording apparatus comprising:
An air intake port provided in the carriage and opened in a moving direction of the carriage;
An exhaust duct for exhausting air taken in from the air intake;
A negative pressure duct connected in the middle of the exhaust duct and flowing air in a direction to be sucked up by an airflow flowing through the exhaust duct,
An ink jet recording apparatus, comprising: a mist collection port formed at an air intake of the negative pressure duct to suction and collect ink mist. 2. The ink jet recording apparatus according to claim 1, wherein one or more ink mist accumulating means for accumulating the collected ink mist is replaceably provided in the exhaust duct. Counting means for counting the number of printed pixels;
3. The ink jet recording apparatus according to claim 2, further comprising: a notifying unit for notifying a replacement time of the mist accumulating unit based on the accumulated number of pixels from the counting unit. 4. The ink jet recording apparatus according to claim 2, wherein the mist accumulating means is provided with a display means for notifying a time of replacement of the mist accumulating means.

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