JP2008093849A - Droplet discharge head and droplet discharge device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a head with a floating mist collecting mechanism in a droplet discharge device (inkjet recording apparatus). <P>SOLUTION: The head or a carriage is covered by an auxiliary member (mist collecting member) with an ink passing opening. Mist floating in the neighborhood of a head face is absorbed in the mist collecting member to prevent the mist from spreading into a machine. In addition, by providing a venting hole in the mist collecting member, air flow generated by operating the carriage is made to flow into the mist collecting member, and only satellite is caught in the collecting member by utilizing a difference between the main droplet and the mass of the satellite. In addition, by connecting a mist sucking fan and a mist absorbing filter to one end of the mist collecting member, mist collecting function is improved. By the above described constitution, it is possible to collect the satellite at an earlier stage after delivery, to decrease generation of the ink mist, and to provide a recording apparatus with higher quality and higher accuracy. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  More particularly, the present invention relates to an ink jet recording apparatus head that performs recording on a recording medium by discharging ink droplets, and the recording apparatus.

  Many recording apparatuses have been proposed so far, and among them, there is a drop-on-demand ink jet recording system. The ink jet recording method simply ejects ink droplets with physical force (ink film boiling phenomenon caused by rapid heating) and landes on the recording medium for recording, so it can be recorded on various recording media. In addition, there is a feature that high-definition images can be obtained at low cost without requiring special processing for fixing the ink. Because of these advantages, the inkjet recording method is used as recording means for printers, copiers, facsimiles, etc. as computer peripherals as one of inexpensive and easy recording devices, and as output means for image documents at home and office. Widely used. In recent years, with the spread of digital cameras, it has been used as digital image output at home, and high-definition output is required. For this reason, attempts have been made to reduce the size of the image forming dots by reducing the size of the discharged droplets and to increase the discharge frequency in order to increase the printing speed.

For example, Patent Document 1 and Patent Document 2 can be cited as conventional examples.
JP 07-101082 A Japanese Patent Laid-Open No. 10-016231

  With such miniaturization of ejected droplets, problems that have not occurred so far have become apparent, and one of them is the problem of ink mist. The secondary droplets (hereinafter referred to as satellites) generated following the main droplets of the ejected droplets float in the machine and become ink mist due to the airflow caused by the carriage operation, and the recording medium, head and unspecified in the machine This may cause a decrease in printing quality or malfunction of the recording apparatus.

  The decrease in print quality is primarily due to the ink mist adhering directly to the recording medium and the ink mist adhering to the member indirectly soiling the recording medium. Specifically, among the members, members that are in direct contact with the recording medium during a printing operation, such as a pickup roller (paper feeding unit) and a pinch roller (paper discharging unit), generate charges due to friction with the recording medium, Are attracted to these charged members, and ink mist is deposited. The accumulated ink mist comes into contact with the recording medium during printing, and the printing surface and back surface of the recording medium are soiled. The second cause of the deterioration in print quality is ejection disturbance due to ink mist adhering to the vicinity of the ejection port. Due to the interaction between the ink mist adhering to the vicinity of the ejection port and the ejection droplet, the ejection trajectory of the ejection droplet deviates from the planned trajectory, and the landing accuracy of the ejection droplet deteriorates. Leading to a decline. The influence of the ink adhering to the vicinity of the ejection port tends to increase as the mass of the ejected droplet decreases, and this problem is caused by the smaller droplet size of ink droplets accompanying the recent high performance of inkjet printers. It is expected to manifest.

  Further, the ink mist may cause malfunction of the ink jet recording apparatus. If ink mist adheres to the encoder film for detecting the carriage position or the light receiving part of the sensor, the carriage position cannot be detected accurately, and the printer operation may be stopped due to printing failure or carriage error. Also, ink mist may adhere to the substrate wiring of the recording apparatus, and the wiring may be short-circuited.

  Thus, since ink mist causes the quality of the recording apparatus to deteriorate, reduction of ink mist is an important issue.

  As countermeasures against these problems, neutralization work for members to which ink mist easily adheres, improvement of the shape of the encoder portion, and the like have been made, and partial effects have been achieved. As a method of actively collecting ink mist, an air flow is generated between the head and the print medium, and a fan is installed to prevent the ink mist from staying. Although it has been devised to electrically pull the recording medium, there are many practically difficult points, and no effective method for reducing in-flight mist has been found.

  An object of the present invention is to provide a high-definition and high-quality ink-jet recording apparatus equipped with an ink-jet recording head that can effectively recover ink mist that causes the above-described problems and eject small droplets.

  According to the first aspect of the present invention, in the droplet discharge head provided with a plurality of discharge ports for discharging droplets, the droplet discharge head or the carriage thereof has an ink passage port. (Hereinafter referred to as an ink mist collecting member).

  Thus, by covering the head and the carriage with the ink mist collecting member, the influence of the air flow generated by the carriage operation is eliminated, and the ink mist floating near the head face surface is collected and prevented from being diffused into the apparatus. effective. In the second aspect of the present invention, the ink absorption amount can be increased by providing the droplet absorbing member in the vicinity of the ink passage opening of the ink mist collecting member and on the inner wall of the member. The shape of the passage opening of the collecting member is approximately circular corresponding to the discharge opening in a one-to-one correspondence (claim 3), and it is easy to trap the satellite. From the viewpoint of the alignment accuracy of the collecting member, it may have a slit shape in which the passage opening is opened substantially in the nozzle row direction (claim 4). Further, in order to enhance the ink mist collecting effect, the droplet absorbing member is a charging member (Claim 5), and at least one end of the accessory member is connected to an air suction fan and an ink absorbing filter ( The ink mist drifting in the vicinity of the head face surface may be positively sucked.

  According to a seventh aspect of the present invention, in the droplet discharge head provided with a plurality of discharge ports for discharging droplets, the head or the carriage includes at least one vent hole, an air flow path, and an ink passage port. It is covered with the ink mist collection member which has this. In this way, a vent is provided in a part of the accessory member (both end surfaces in the carriage scanning direction), air is introduced from the vent, and a lateral wind is applied to the flying droplet immediately after ejection, thereby allowing the main droplet and the satellite to By utilizing the difference in mass, only the satellite can be trapped in the ink collecting member (FIG. 8). Therefore, not only small satellites floating in the vicinity of the discharge port but also large satellites that adversely affect the image can be collected.

  As described above, in a droplet discharge head provided with a plurality of discharge ports for discharging droplets, the head or the carriage is covered with an accessory member (mist collecting member) having an ink passage port. It is characterized by. Thereby, there is an effect of collecting the mist floating near the head discharge port surface and preventing the mist from spreading. By using the inner wall of the attachment member as a droplet absorbing member, it is possible to promote adsorption of mist and enhance the mist collecting effect. Further, by providing a vent hole in the mist collecting member and allowing an air flow generated by the carriage operation to flow in, satellites can be trapped by the mist collecting member using the mass difference between the main droplet and the satellite. This makes it possible to effectively collect satellites that cause mist generation immediately after droplet formation. Furthermore, the mist collection effect can be enhanced by connecting an air suction fan and an ink absorption filter to at least one end of the mist collection member.

  Hereinafter, specific embodiments of the present invention, particularly ink jet recording apparatuses, will be described in detail with reference to the drawings.

(Outline of configuration of inkjet recording apparatus)
FIG. 1 is a schematic diagram of an ink jet recording apparatus 1 suitable for the present invention. The recording medium is installed in the paper feed tray 2 and conveyed in the recording medium conveyance direction. Correspondingly, the carriage 4 fixed to the shaft 3 reciprocates in the direction perpendicular to the recording medium conveyance direction, and ejects droplets from the droplet ejection head to print on the recording medium.

  Hereinafter, the mist collecting function provided in the carriage 4 which is the main part of the present invention will be described with various embodiments.

  A first embodiment is shown in FIG. FIG. 2 is a schematic view of a cross section of the carriage 4 of the ink jet recording apparatus 1 suitable for the present invention. In a droplet discharge head 5 provided with a plurality of discharge ports for discharging droplets, the surface of the discharge port and the discharge head 5 are covered with an attachment member 7 (hereinafter referred to as an ink mist collecting member) having an ink passage port 6. The droplet absorbing member 8 is provided in the vicinity of the passage opening. In this embodiment, the mist collecting member 7 covers the carriage 4 and is integrated with the carriage 4.

  As described above, the main cause of the occurrence of ink mist is the satellite of the ejected droplets, and these sizes are droplets having a diameter of 2 μm to 10 μm and a velocity of 10 m / s or less. Conventionally, these small droplets cannot reach the surface of the paper due to air resistance, become floating mist drifting near the head face surface, and are diffused in the machine due to the influence of the airflow generated by the carriage operation. The mist collecting member 7 of the present invention shown in FIG. 2 has an effect of covering the carriage, eliminating the influence of the airflow generated by the carriage operation on the floating mist, and preventing the floating mist from diffusing into the machine. Further, the ink absorbing member 8 provided in the vicinity of the ink passage opening has an effect of promoting the absorption of floating mist and preventing ink leakage from the ink mist collecting member 7.

  The ink mist collecting member 7 is a material such as an absorbent polymer made of an electrolyte for the ink absorbing member, such as a light-weight, low-strength, low-water-absorbing PPE (polyphenylene ether) resin or a glass fiber in them. It is desirable to be formed from.

  Here, as a variation of the first embodiment, the droplet discharge head 5 itself is formed with an ink mist collecting member (FIG. 3), or the ink mist collecting member 7 can be separated from the carriage 4 and the head 5, Including forms that can be easily removed directly. As shown in FIG. 9, the shape of the ink passage port 6 is not limited to a substantially circular shape corresponding to the ejection port of the recording head 5, and may be a substantially circular shape such as an ellipse or a polygonal shape. Moreover, as shown in FIG. 10, you may have the slit shape opened in the nozzle row direction. Further, by providing an open surface on the ink mist collecting member 7 separately from the vent 9 (preferably a direction perpendicular to the main scanning direction of the carriage), the head face surface may be capped or wiped. .

  As a second embodiment, in addition to the first embodiment described above, a part of the ink mist collecting member has at least one vent hole.

  As shown in FIG. 4, the basic configuration of the ink mist collecting mechanism of the present embodiment is the same as that of the first embodiment, but a vent hole 9 is provided on the scanning direction surface of the carriage of the ink mist collecting member 7. It is characterized by. By providing the air vent 9 and allowing the air flow generated by the carriage operation to flow from the air vent 9, the satellite collection efficiency at the ink passage port 6 can be increased. As shown in FIG. 8, the satellite has a smaller mass than the main droplet and is easily affected by the external airflow. Therefore, when air is introduced from the air vent 9 and a cross wind is applied to the flying droplet, the satellite orbit is displaced more greatly than the main droplet, and the satellite cannot pass through the ink passage port 6, so that the satellite is misted (FIG. 11). Can be trapped. Thereby, generation | occurrence | production of ink mist can be suppressed, it can collect efficiently, and the generation amount of mist can be reduced. Here, the mist collecting effect is enhanced as the diameter of the ink passage port 6 is reduced to approach the discharge port diameter of the droplet discharge head 5. As shown in FIG. 9, the shape of the ink passage port 6 is not limited to a substantially circular shape corresponding to the ejection port of the recording head 5, and may be a substantially circular shape such as an ellipse or a polygonal shape. Moreover, as shown in FIG. 10, you may have the slit shape opened in the nozzle row direction.

  Here, as a variation of the second embodiment, an ink mist collecting member is formed on the droplet discharge head 5 itself (FIG. 5), or the ink mist collecting member 7 is integrated with the carriage 4 or the head 5. In addition to the above, there may be a form that can be easily removed directly. Further, by providing an open surface on the ink mist collecting member 7 in addition to the vent hole 9 (preferably in a direction perpendicular to the main scanning direction of the carriage), capping and wiping of the head face surface may be performed. .

  As a third embodiment, as shown in FIG. 6, at least one end of the ink collecting member 7 is connected to the air suction fan 10 and the ink absorption filter 11. Unlike the embodiment described above, a fan for sucking ink is provided to positively collect ink mist. Thereby, generation | occurrence | production of ink mist can be suppressed.

  Here, as a variation of the third embodiment, as in the second embodiment, the ink collecting member 7 may have a vent 9. (FIG. 7) As shown in FIG. 9, the shape of the ink passage port 6 is not limited to a substantially circular shape corresponding to the ejection port of the recording head 5, but may be a substantially circular shape such as an ellipse or a polygonal shape. It may be. Moreover, as shown in FIG. 10, you may have the slit shape opened in the nozzle row direction.

It is a schematic diagram of implementation of the droplet discharge device suitable for the present invention. It is one of the schematic schematic drawings of a carriage and a mist collecting member cross section of the droplet discharge device according to the first embodiment of the present invention. The entire carriage is covered with a mist collecting member. It is one of the schematic schematic drawings of a carriage and a mist collecting member cross section of the droplet discharge device according to the first embodiment of the present invention. The entire droplet discharge head is covered with a mist collecting member. It is one of the schematic schematic diagrams of a carriage and a mist collecting member cross section of a droplet discharge device according to a second embodiment of the present invention. The entire carriage is covered with a mist collecting member. It is one of the schematic schematic diagrams of a carriage and a mist collecting member cross section of a droplet discharge device according to a second embodiment of the present invention. The entire droplet discharge head is covered with a mist collecting member. In this invention, it is the figure which wrote typically the mechanism which catches a satellite with a mist collection member. It is one of the schematic schematic diagrams of a carriage and a mist collecting member cross section of a droplet discharge device according to a third embodiment of the present invention. The entire carriage is covered with a mist collecting member, and one end of the mist collecting member is connected to a mist suction fan and a mist absorbing filter. It is a figure for demonstrating the mechanism which catches a satellite. It is a figure which shows the passage opening shape of a mist collection member. It is a figure which shows the passage opening shape of a mist collection member. It is a figure for demonstrating the droplet distribution of a discharge droplet.

Claims (24)

  A droplet discharge head provided with a plurality of discharge ports for discharging droplets, wherein the head or the carriage is covered with an accessory member having an ink passage port. .   The droplet discharge head according to claim 1, wherein a droplet absorbing member is provided in the vicinity of the passage opening and on the inner wall of the accessory member in the accessory member.   The droplet discharge head according to claim 2, wherein the attachment member has a substantially circular shape and has a one-to-one correspondence with the discharge port.   The droplet discharge head according to claim 2, wherein the attachment member has a slit shape in which the passage port is opened in a nozzle row direction.   5. The droplet discharge head according to claim 3, wherein the droplet absorbing member is a charging member.   5. The droplet discharge head according to claim 3, wherein at least one end of the attachment member is connected to an air suction fan and an ink absorption filter.   In a droplet discharge head provided with a plurality of discharge ports for discharging droplets, the head or the carriage is covered with an accessory member having at least one ventilation port, an air flow path, and an ink passage port. A droplet discharge head characterized by that.   8. The droplet discharge head according to claim 7, wherein a droplet absorbing member is provided in the vicinity of the passage opening and on the inner wall of the accessory member in the head accessory member.   8. The droplet discharge head according to claim 7, wherein in the attachment member, the passage port has a substantially circular shape and has a one-to-one correspondence with the discharge port.   8. The droplet discharge head according to claim 7, wherein the attachment member has a slit shape in which the passage opening is opened in a nozzle row direction. 9.   The droplet discharge head according to claim 9, wherein the droplet absorbing member is a charging member.   11. The droplet discharge head according to claim 9, wherein at least one end of the attachment member is connected to an air suction fan and an ink absorption filter.   A droplet discharge apparatus provided with a plurality of discharge ports for discharging droplets, wherein the head or the carriage is covered with an accessory member having an ink passage port. .   14. The droplet discharge head according to claim 13, wherein a droplet absorbing member is provided in the vicinity of the passage opening and on the inner wall of the accessory member in the accessory member.   The droplet discharge device according to claim 14, wherein in the attachment member, the passage port has a substantially circular shape and has a one-to-one correspondence with the discharge port.   The droplet discharge device according to claim 14, wherein the attachment member has a slit shape in which the passage port is opened in a nozzle row direction.   The liquid droplet ejection apparatus according to claim 15, wherein the liquid droplet absorbing member is a charging member.   17. The droplet discharge device according to claim 15, wherein at least one end of the attachment member is connected to an air suction fan and an ink absorption filter.   In a droplet discharge head provided with a plurality of discharge ports for discharging droplets, the head or the carriage is covered with an accessory member having at least one ventilation port, an air flow path, and an ink passage port. A droplet discharge device characterized by that.   20. The droplet discharge device according to claim 19, wherein the head attachment member is provided with a droplet absorption member in the vicinity of the passage opening and on the inner wall of the attachment member.   The droplet discharge device according to claim 19, wherein the attachment member has a substantially circular shape and has a one-to-one correspondence with the discharge port.   The droplet discharge device according to claim 19, wherein the attachment member has a slit shape in which the passage opening is opened in a nozzle row direction.   23. The droplet discharge device according to claim 21, wherein the droplet absorbing member is a charging member.   23. The droplet discharge device according to claim 21, wherein at least one end of the attachment member is connected to an air suction fan and an ink absorption filter.

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