JP2008178998A - Inkjet recorder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent clogging of an ink ejection port by preventing drying of ink in the ink ejection port at the time of non printing in an inkjet recorder which uses the water-based ink. <P>SOLUTION: A waste ink pipe 51 and a steam pipe 52 are formed between a cap member 3 which covers the ink ejection port 21 of a recording head 2 at the time of non printing and a waste ink tank 4. The waste ink tank 4 is heated by a heater H to fill the interior of the cap member 3 with the ink steam. From the viewpoint of filling the interior of the cap member 3 with the ink steam and saving of energy, it is preferable to heat the waste ink stored in the waste ink tank 4 to 40-80°C. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an ink jet recording apparatus, and more particularly to an ink jet recording apparatus used in a recording apparatus such as a facsimile, a printer, and a copying machine.

  An ink jet recording apparatus is a recording apparatus that directly prints on a recording medium by ejecting minute ink droplets from a plurality of ink discharge ports formed in a recording head, and is capable of simple and high-speed printing. In this ink jet recording apparatus, in order to perform printing with high image quality and high resolution, it is necessary to make the diameter of the ink ejection port minute. However, if the diameter of the ink ejection port is made minute, the ink viscosity must be printed for a long time. Becomes higher, and the ink discharge port is likely to be clogged. When the ink discharge port is clogged, printing defects such as missing dots and vertical stripes occur.

  Therefore, in the conventional ink jet apparatus, when printing is not performed, the recording head is covered with a cap member to prevent drying of ink in the ink discharge port and mixing of dust or the like. Even during printing, the recording head is moved to the capping position every predetermined number of times or every predetermined time, and ink is discharged from all ink discharge ports, so-called purging is performed to prevent clogging of the ink discharge ports. It was. Further, if necessary, the ink is forcibly discharged from the ink discharge port by suctioning the pump, thereby eliminating the clogging of the ink discharge port.

In Patent Document 1, an ink reservoir for storing a certain amount of waste ink is provided between the cap member and the waste ink tank, and a fiber member is inserted between the ink reservoir and the cap member. A technique has been proposed in which a path is formed and the cap member is always filled with ink vapor to prevent clogging of the ink discharge port.
Japanese Utility Model Publication No. 6-21939 JP-A-11-157090

  However, in the proposed technique, if the ambient temperature around the cap member and the ink reservoir is low, the cap member may not be sufficiently filled with ink vapor. In particular, when a line head is used as the recording head, the cap member that covers the line head is also large, so it is more difficult to fill the cap member with ink vapor.

  The present invention has been made in view of such a conventional problem, and an object of the present invention is to prevent ink from drying in an ink discharge port when the recording apparatus is not used, and to provide an ink jet with high printing reliability. It is to provide a recording apparatus.

  According to the present invention, in an ink jet recording apparatus that performs printing on paper by discharging aqueous ink from a plurality of ink discharge ports formed in the recording head, the cap member that covers the ink discharge ports of the recording head when not printing And a waste ink tank for storing waste ink, a heating member for heating the waste ink tank, and a waste ink flow path and a vapor flow path formed between the cap member and the waste ink tank, An inkjet recording apparatus is provided.

  From the viewpoint of filling the cap member with ink vapor and saving energy, it is preferable that the waste ink stored in the waste ink tank is heated to 40 to 80 ° C.

  From the viewpoint of fully enjoying the effects of the present invention, it is preferable to use a so-called line head having 500 or more ink discharge ports as the recording head.

  In the ink jet recording apparatus of the present invention, the heating member is provided to heat the waste ink tank and the ink vapor is actively generated from the waste ink tank. Therefore, unlike the conventional apparatus, the ambient temperature is low. However, the cap member can be sufficiently filled with ink vapor without running out of ink vapor. Even when a line head having a width wider than that of the serial head is used, the cap member can be sufficiently filled with ink vapor. In addition, since the waste ink in the waste ink tank is heated and concentrated, the volume of the waste ink tank can be made smaller than before.

  When the temperature of the waste ink stored in the waste ink tank is 40 to 80 ° C., the cap member can be filled with ink vapor and at the same time energy saving can be achieved.

  When a so-called line head having 500 or more ink discharge ports is used as the recording head, the effects of the present invention are sufficiently exhibited.

  Hereinafter, the ink jet recording apparatus of the present invention will be described with reference to the drawings. The present invention is not limited to these embodiments.

FIG. 1 is a schematic view showing an embodiment of an ink jet recording apparatus according to the present invention. In the ink jet recording apparatus of FIG. 1, the paper P conveyed from a paper feed cassette (not shown) moves in the direction of the arrow in the figure. A drive shaft 61 and a support shaft 62 are attached in parallel to opposite side plates (not shown) so as to be orthogonal to the transport direction of the paper P. A carriage 1 having a recording head 2 (shown in FIG. 2) attached to the surface facing the paper P is attached to a drive shaft 61 and a support shaft 62 so as to be movable in the axial direction. Specifically, the drive shaft 61 is a male screw, and a female screw is formed on the inner peripheral surface of the through hole 13 of the carriage 1 through which the drive shaft 61 is inserted. A motor M ₂ is attached to one end of the drive shaft 61. On the other hand, a linear groove 12 is formed in the axial direction on the protrusion 11 protruding from the side surface of the carriage 1, and a support shaft 62 is engaged with the groove 12. Drive shaft 61 and the motor M ₂ rotates is rotated, the carriage 1 is prevented from rotating together of the carriage 1 by the support shaft 62 moves in the axial direction.

  The carriage 1 moves in a direction orthogonal to the paper transport direction while the transport of the paper P that is intermittently transported is stopped, and a plurality of ink discharge ports 21 (shown in FIG. 2) attached to the carriage 1 during this time. Predetermined printing is performed on the paper by the formed recording head 2 (shown in FIG. 2).

  A position (home position) where the carriage 1 stands by when not printing is provided outside the sheet conveyance area (right side in the figure). Here, a cap member 3 that covers the ink discharge port 21 of the recording head 2 is provided. In addition, a waste ink tank 4 for collecting waste ink purged from the recording head 2 is provided, and a heater (heating member) H is attached to the outside of the waste ink tank 4. The cap member 3 and the waste ink tank 4 are communicated by a waste ink pipe (waste ink flow path) 51 and a vapor pipe (vapor flow path) 52.

The cap member 3 has a box shape in which a surface facing the recording head 2 is opened, and a protrusion 31 in which a through hole 32 is formed extends on a side surface of the cap member 3. A female screw is formed on the inner peripheral surface of the through hole 32, and a drive shaft 63 made of a male screw is inserted through the through hole 32. A motor M ₁ is attached to one end of the drive shaft 63, and when the motor M ₁ rotates, the drive shaft 63 rotates and the cap member 3 moves in the axial direction.

When the printing operation is completed, the carriage 1 moves to the home position, and the cap member 3 is raised by the rotation of the motor M ₁ and is attached to the recording head 2 so as to cover the ink discharge port 21 as shown in FIG. An elastic sealing material 33 is attached to the upper inner periphery of the cap member 3 in order to improve airtightness.

  When the cap member 3 is attached to the recording head 2, the first valve 71 provided in the middle of the waste ink pipe 51 is closed, and the second valve 72 provided in the middle of the vapor pipe 52 is opened. On the other hand, since the waste ink in the waste ink tank 4 is heated by the heater H, when the second valve 72 is opened, the ink vapor flows into the cap member 3 through the vapor pipe 52, and the inside of the cap member 3 is High humidity is maintained by ink vapor. As a result, clogging due to drying and solidification of ink at the ink discharge port 21 that has occurred in the past can be effectively suppressed.

  When the print start signal is input, the second valve 72 is closed and the first valve 71 is opened, a purge is performed to eject ink from all the ink ejection ports 21, and the ink that has been in contact with the ink vapor is discarded. This is because there is a possibility that the density of the ink may be reduced due to contact with the ink vapor. Of course, the purge may not be performed when the concentration of the ink in contact with the ink vapor is within a practical range. The purged waste ink flows to the waste ink tank 4 through the waste ink pipe 51. The first valve 71 may be left open until the recording head 2 returns to the home position again. However, from the viewpoint of preventing the entry of foreign matter and the discharge of ink vapor, the ink purge is completed. It is better to close it after a while.

  The set temperature of the heater H, that is, the retention temperature of the waste ink in the waste ink tank 4 is usually preferably about 40 ° C. to 50 ° C. from the viewpoint of energy saving. However, when the main power of the apparatus is turned on, the apparatus may not be used for a long period of time. Therefore, it is preferable to set the set temperature of the heater H as high as 70 to 80 ° C. As a result, even if the ink is dried and solidified at the ink discharge port 21, the solidified product can be dissolved by the ink vapor.

  The ink used in the present invention needs to be a water-based ink. This is because in the case of water-based ink, the ink vapor generated by heating is almost water vapor. In the present specification, the water-based ink is one having a water content of 50% by weight or more. In addition, at the beginning of use of the apparatus, the waste ink tank is filled with a small amount of ink or water in advance.

(Preparation of pigment dispersion)
The following raw materials were mixed, and 0.5 mm zirconia beads were used and dispersed with a ball mill until the average particle size became 100 nm to obtain a magenta pigment dispersion. The average particle size is measured using a dynamic light scattering particle size distribution measuring device ("LB-550" manufactured by HORIBA) after diluting the pigment dispersion with ion-exchanged water 5 times.
C. I. Pigment Red 122 30wt%
Jonkrill 61 15wt%
(Acrylic-styrene resin, manufactured by Johnson)
Glycerin 10wt%
Ion exchange water 45wt%

(Preparation of ink)
Using the prepared magenta pigment dispersion, each material was blended so as to have the following composition, sufficiently stirred, and then filtered using a filter having a pore size of 5 μm to obtain an ink.
Surfactant 0.5wt%
("Orphine E1010" manufactured by Nissin Chemical Industry Co., Ltd.)
Hexylene glycol 5wt%
2-pyrrolidone 5wt%
Glycerin 10wt%
Pigment dispersion 20wt%
Water remaining

(Example 1)
The ink prepared above is mounted on the ink jet recording apparatus having the structure shown in FIG. 1 and FIG. went. A schematic diagram of the printing test results is shown in FIG.

(Comparative Example 1)
A printing test was conducted in the same manner as in Example 1 except that the heater was not attached to the waste ink tank, and the waste ink tank was left at room temperature for 30 days. A schematic diagram of the print test results is shown in FIG.

  As can be seen from FIG. 3, in the ink jet recording apparatus of Example 1, the waste ink tank was kept at 40 ° C., so the ink discharge port was not clogged and the dots were printed cleanly from the start of ink discharge. ing. On the other hand, as shown in FIG. 4, in the ink jet recording apparatus of Comparative Example 1, the waste ink tank was kept at the ambient temperature without being heated. It was “missing”. Also, dots having a high ink density were printed for a while after the second time.

1 is a schematic diagram illustrating an embodiment of a printing unit of an ink jet recording apparatus according to the present invention. It is an operation | movement figure in the home position of a cap member. FIG. 3 is a schematic diagram showing a print test result of the ink jet recording apparatus of Example 1. 6 is a schematic diagram showing a print test result of the ink jet recording apparatus of Comparative Example 1. FIG.

Explanation of symbols

1 Carriage 2 Recording Head 3 Cap Member 4 Waste Ink Tank H Heater (Heating Member)
P Paper 21 Ink protrusion hole 51 Waste ink tube (Waste ink flow path)
52 Steam pipe (steam channel)

Claims (3)

In an inkjet recording apparatus that performs printing on paper by discharging aqueous ink from a plurality of ink discharge ports formed in a recording head,
A cap member that covers the ink discharge port of the recording head during non-printing, a waste ink tank that stores waste ink, a heating member that heats the waste ink tank, and waste formed between the cap member and the waste ink tank. An ink jet recording apparatus comprising an ink channel and a vapor channel.   2. The ink jet recording apparatus according to claim 1, wherein the waste ink stored in the waste ink tank is heated to 40 to 80 [deg.] C. by the heating member.   The inkjet recording apparatus according to claim 1, wherein the recording head has 500 or more ink discharge ports.