JP2005041190A - Inkjet recorder and recovery apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inkjet recorder provided with a recovery means for efficiently recovering a recording head with a simple constitution. <P>SOLUTION: The inkjet recorder makes recording by discharging ink from a nozzle 8 provided in a recording head 14, and is provided with the recovery means for drawing out and removing viscosity-increased ink or foreign matters from the nozzle 8 of the recording head 14. The recovery means is provide with: a capillary force generating section 3 to generate a capillary force stronger than that of the nozzle 8 of the recording head 14; and a moving means for moving the capillary force generating section 3 such that the section 3 is brought into contact with or separated from the nozzle 8 by relatively moving the section 3 forward and backward against the nozzle 8. Further, the capillary force generating section 3 has a structure wherein the capillary force increases as the section 3 is separated from the nozzle 8. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

    The present invention relates to an ink jet recording apparatus and a recovery apparatus provided with recovery means for drawing out and removing thickened ink or foreign matter from nozzles of a recording head.

  Since the ink jet recording apparatus employs a method of performing recording by ejecting ink droplets from the recording head, when the nozzles of the recording head are exposed to the atmosphere, the moisture of the ink evaporates and the viscosity increases (hereinafter, (This is called thickening) and foreign matter such as paper dust enters the recording head, making it difficult for the ink to be ejected when recording starts, or causing the ink to become completely unejected. May cause defects.

In such a case, in an ink jet recording apparatus, a recovery process is generally performed in which ink and foreign matters that are not suitable for ejection inside the nozzle are removed, and the inside of the nozzle is replaced with fresh ink to enable an appropriate recording operation. .
Conventionally, as this recovery process, by covering the nozzle with an ink cap when necessary (hereinafter, this operation is referred to as capping), by sucking the inside of the cap and sucking out the thickened ink or foreign matter in the nozzle from the nozzle, The suction recovery operation to make the recording head recordable again, and the recording head forcibly discharges the ink and foreign matter that are thickened from the nozzles by pressurizing the ink from the upstream part in the ink supply flow path to the recording head. Has been performed, such as a pressure recovery operation to make a recordable state.

  However, when the recording head to be subjected to the recovery process is a long full line head in which nozzles are arranged over the entire width of the recording area of the recording medium, in the suction recovery operation as described above, capping is performed on the recording head. However, there was a problem that it could not be performed accurately.

  In addition, when a pressure recovery operation is performed on a full line head, ink is discharged from all nozzles, so ink is also discharged from many nozzles that do not require recovery processing. Therefore, there is a problem that the amount of ink ejected in the recovery process becomes larger than necessary.

  However, for this problem, measures are taken to avoid an increase in ink consumption by adopting an ink recycling system that returns the discharged ink to the ink tank through a filter. In such an ink recycling system, in addition to the problem that the ink flow path connecting each unit constituting the system becomes complicated, the ink flow path is pressurized by the pressurizing means, so that the connection between the units in each flow path is There is a new problem that the portion is easy to loosen, and in some cases, ink leaks from the coupling portion.

  Therefore, as a recovery process for a full-line head that is simpler and more efficient than suction recovery processing or pressure recovery processing, the capillary force generating member is simply pressed against the nozzle or inserted into the nozzle. It has been proposed to recover by extracting and removing foreign matters such as thickened ink, bubbles and paper dust in the nozzle of the recording head by the generated capillary force (see, for example, Patent Document 1).

JP-A-6-336032

  However, the recovery process by the recovery device disclosed in the above-mentioned patent document, that is, by simply pressing a single capillary force generating member against the nozzle of the recording head or inserting it into the nozzle, the increase in the nozzle in the recording head is achieved. At present, foreign substances such as viscous ink, bubbles and paper dust cannot be completely drawn out and removed, and an efficient recovery operation has not been realized.

  Therefore, in this recovery process using the capillary force generating member, in order to perform an efficient recovery operation, the capillary force generating member disposed in the capping mechanism is pressed or inserted into the nozzle, and then the nozzle is operated with a relatively small force. Although a method of performing a recovery operation by suction or pressurization is considered, after all, this requires a device for suction or pressurization, and does not solve the above-described problem, An increase in the size of the ink jet recording apparatus main body and an increase in manufacturing cost cannot be avoided.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide an inkjet recording apparatus and a recovery apparatus that include recovery means capable of efficiently recovering a recording head with a simple configuration. On offer.

In order to achieve the above object, the present invention has the following configuration.
That is, the present invention provides an ink jet recording apparatus that performs a recording operation by ejecting ink from nozzles provided in a recording head, and includes recovery means that draws and removes thickened ink or foreign matter from the nozzles of the recording head. The recovery means includes an ink suction portion that sucks ink by generating a capillary force larger than the nozzle of the recording head, and the capillary force generation portion by moving the capillary force generation member relative to the nozzle. Moving means for moving the ink in contact with and away from the nozzle, and the ink suction portion has a structure in which a capillary force increases in a direction away from the nozzle.

  As described above, in the present invention, since the capillary force generating member has a structure in which the capillary force increases in the direction away from the nozzle, the ink inside the nozzle can be drawn out smoothly and continuously. It becomes possible. For this reason, a suction device or a pressurizing device having a complicated structure which has been conventionally used is not required, and the main body device can be reduced in size and cost.

Embodiments of the present invention will be described with reference to the drawings.
Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.
First, an ink jet recording apparatus according to an embodiment of the present invention and a full line type recording head applied thereto will be described.

FIG. 1 is a perspective view illustrating a part of an ink jet recording apparatus according to an embodiment of the present invention.
In FIG. 1, an ink jet recording apparatus 30 is mainly fed from the four recording heads 14 to 17 and a supply unit 20 for supplying recording paper 18 as a recording medium into the recording apparatus main body 21, and the supply unit 20. A unit 19 for transporting the recording paper 18 to a position facing the recording heads 14 to 17, a recovery device for stabilizing the ejection of ink in the recording heads 14 to 17, and a control device for controlling the entire device. It has composition which has.

  Here, the supply unit 20 holds a roll-shaped recording paper 18, and the transport unit 19 continuously transports the recording paper 18 to the recording heads 14 to 17 and the rear thereof. Each of the recording heads 14 to 17 ejects ink when the reference position of the recording paper moves downward. In this embodiment, a black recording head 14, a cyan recording head 15, a magenta recording head 16, and a yellow recording head 17 are sequentially arranged along the recording sheet conveyance direction. Ink is ejected in the order of cyan, magenta, and yellow, thereby forming a color image.

  In the figure, reference numeral 22 denotes an opening / closing door for exposing the internal structure in the operation of replacing the ink cartridge provided in the recording apparatus main body 21.

  FIG. 2 is a schematic diagram for explaining the internal structure of the recording heads 14 to 17 used in this embodiment. Since each recording head has the same internal structure, the following description will be made taking one recording head 14 as an example.

  Each nozzle 12 of the recording head 14 is provided with a corresponding heating element 14 (heater), and when the head drive circuit supplies a predetermined energy to the heater 14, the heater 14 is heated and placed in the ink. Bubbles are generated, and ink droplets are discharged from the ink discharge port 8a by the generated energy (pressure) of the bubbles. The heater 14 is formed on the silicon substrate 7 by the same method as in the semiconductor manufacturing process. Further, 9 is a nozzle partition that constitutes each nozzle 12, 11 is a common liquid chamber for supplying ink to each nozzle 12, and 13 is a top plate.

  The recording head 14 having the internal structure as described above is a long full line head in which the nozzles 12 are formed over a width equal to or larger than the maximum width of the recording medium to be used. The recording heads are arranged such that the longitudinal direction (nozzle arrangement direction) is perpendicular to the conveyance direction of the recording medium 18 as shown in FIG.

  FIG. 3 is a longitudinal side view showing a schematic configuration of a recovery device as recovery means for removing thickened ink remaining in each nozzle and foreign matters such as paper dust and dust with respect to the full line head. .

  The recovery device 1 shown here includes a container-shaped recovery device member 2 that does not have ink permeability, and an ink absorption unit 3 that is accommodated in the recovery device member 2. The recording head 14 is provided at a position facing the ejection port 8a.

  Further, the recovery device member 2 is provided so as to be lifted and lowered by a lifting mechanism (not shown). When the lifting device member 2 is lifted, the ink absorbing portion 3 is formed at the lower end of the recording head 14 as shown in FIG. At the time of lowering, the recording medium 18 is separated from the recording head 14 and can move to the space therebetween.

  The ink absorbing portion 3 may be provided corresponding to each recording head 14 in the recovery device member 2, but the recovery device member 2 is provided for each recording head 14, and the recording head 14 is provided with respect to each recording head 14. It is also possible to adopt a configuration that can be raised and lowered separately.

  The ink absorbing section 3 in this embodiment includes an upper porous member 3a as a capillary force generating member that contacts the nozzle 8 of the recording head 14, and a capillary that superposes in the vertical direction with respect to the upper porous member 3a. The lower porous body 3b as a force generating member forms a two-layer structure. The upper porous member 3a is formed with pores having a smaller diameter than the ink discharge port 8a provided in the nozzle 8 of the recording head 14, and is formed relatively thin. The lower porous body 3b is a high-density porous body in which the elevation is further smaller than that of the upper porous member 3a, and is thicker than the upper porous member 3a.

  Here, as the upper porous member 3a, for example, there is a polypropylene porous film in which pores having a diameter of about 0.2 μm are formed in about 35% of the total volume, and the lower porous body 3b. As such, a lump of polypropylene fibers of 2 diol fiber (density: 0.025 g / c) can be applied.

Next, the operation of the recovery device having the above configuration will be described.
When recovering the full line head 4, the upper porous member 3 a of the ink absorbing portion 3 is pressed or inserted into the nozzle 8 by pressing against the nozzle 5 of the full line head 4.

  When discharging the thickened ink remaining in the nozzle 8 to the recording head 14, the ink absorbing portion 3 is raised together with the recovery device member 2 by a lifting mechanism (not shown). As a result, the ink absorbing portion 3 rises from the standby state shown in FIG. 1A to the recovered state shown in FIG. 1B and contacts the nozzles 8 of the recording head 14.

  As is well known, since the capillary force increases as the capillary radius decreases, when the ink absorbing portion 3 having a small hole sufficiently smaller than the nozzle diameter is brought into contact with the nozzle 8 as described above, the capillary due to the surface tension of the ink is used. The ink in the nozzle 8 is first drawn by the upper porous member 3 a disposed above the ink absorbing portion 3 by the action of the ink absorbing portion 3 that generates a capillary force larger than the force.

  Next, the ink drawn from the nozzle 8 is once absorbed by the upper porous member 3a as a capillary force generating member, but gravity acts on the ink itself, and the upper porous member 3a is thin and has a low density. Therefore, the ink reaches the bottom surface of the lower porous body 3b disposed immediately below the upper porous member 3a. Since the lower porous body 3b is formed at a higher density than the upper porous member 3a and generates a larger capillary force, the ink that has reached the lower porous body 3b enters the lower porous body 3b. It moves smoothly and finally reaches the bottom surface of the recovery device member 2 that holds the lower porous body 3b. Thereafter, the ink that has reached the bottom surface is collected in an ink discharge port 6 formed on the side along the bottom surface, and is transported from here to a tank (not shown) by its own weight and collected.

  Although FIG. 3 shows the case where the bottom surface portion of the recovery device member 2 is formed horizontally, the shape of the bottom surface portion of the recovery device member 2 is changed to the ink discharge port in order to enhance the liquid collecting effect of the drawn ink. The ink discharge port may be arranged at the center of gravity of the bottom surface portion of the recovery device member, and the shape of the bottom surface portion of the recovery device member is directed toward the ink discharge port. It is also effective to use a funnel.

  As described above, in this embodiment, the lower porous member 3b for generating a larger capillary force is provided immediately below the upper porous member 3a for generating a larger capillary force for the nozzle 8, and this lower porosity is provided. Since the material member 3b is formed thick to secure a large ink receiving amount, a series of suctions for smoothly moving the ink once sucked by the upper porous member 3a to the lower porous member 3b, By the discharging operation, the thickened ink in the nozzle 8 can be drawn out smoothly and continuously, and an excellent ink discharging ability can be obtained for the nozzle 8. For this reason, the suction recovery mechanism or the pressure recovery mechanism having a complicated configuration which has been conventionally used is not required, and the cost of the ink jet recording apparatus can be reduced.

  By the way, in the said embodiment, although the ink absorption part 3 was comprised so that a two-layer structure might be comprised by two types of porous bodies 3a and 3b from which capillary force differs, three or more types of porous bodies are turned downward one by one. It is also possible to form a multilayer structure by polymerizing in such a manner. Also in this case, it is necessary to polymerize each porous body from the one having a low capillary force toward the lower side sequentially.

  In addition, the ink absorbing portion is not limited to the porous member, and can be constituted by other members. In short, in the contact state with the nozzle, the capillary force is stepwise or continuous along the direction away from the nozzle. What is necessary is just to comprise so that it may increase.

  For example, the ink absorbing portion is constituted by a thin tube assembly in which thin tubes (capillary force generating members) smaller than the nozzle diameter are assembled, and the diameter of the thin tube is set in a direction away from the nozzle in a contact state with the nozzle. The diameter may be reduced.

  In this case, when the ink absorbing portion is moved to the nozzle side, the thin tube can be inserted into the nozzle, and the thickened ink in the nozzle can be removed more reliably. If the extending direction of the ink is made coincident with the direction of gravity, the ink can be guided in the discharging direction by capillary force and gravity, and a higher ink discharging ability can be obtained.

  Also, by knitting by combining the fiber direction vertically and horizontally, a plurality of ink absorbers (capillary force generating members) with a small gap smaller than the nozzle diameter of the recording head are polymerized, and the capillary force of each ink absorber is It is also possible to configure the ink absorbing portion so as to sequentially increase along the direction away from the nozzle. In this case, the ink moves not only in the vertical direction but also in the horizontal direction. The liquid collecting effect to the discharge port can be enhanced.

Furthermore, a wire assembly formed by assembling a large number of wires extending in a certain direction is configured as a capillary force generating member, and a minute gap formed between each wire of the wire assembly is formed as a nozzle diameter. If it is formed to be narrower and the minute gap is reduced along the direction away from the nozzle, it can be used as an ink suction portion.
Even in this case, if the extending direction of the wire is arranged along the direction of gravity, the ink can be discharged more smoothly by the weight of the ink.

  Further, in the above embodiment, the ink sucked from the nozzle by the ink absorbing portion is discharged from the discharge port of the recovery device member in a liquid state, but the portion located below the ink absorbing portion (separated from the nozzle) If the surface is exposed to the atmosphere and the water that occupies most of the ink components is evaporated at the bottom, the ink can be held in a small amount of condensed state instead of liquid. It becomes possible.

  In the above embodiment, the inkjet recording apparatus using a long full line head has been described as an example. However, the short recording head performs a recording operation while moving in a direction orthogonal to the recording medium conveyance direction. The present invention can also be applied to a serial type ink jet recording apparatus. In this case, a recovery device member and an ink absorbing portion having a length corresponding to the recording head are provided at a position where the recording head is out of the recording area, and contact and separation operations between the recording head and the recovery device member are performed by well-known recording heads. This can be realized by using a lifting mechanism or a lifting mechanism of a recovery member.

  In addition, the present invention is not limited to using a recording head provided with a heater as an energy generating element for ejecting ink from a nozzle, and other energy generating elements such as a piezo are provided with a recording head provided with an energy generating element. It is also applicable to what is used.

FIG. 3 is an explanatory perspective view illustrating a part of the ink jet recording apparatus according to the embodiment of the present invention. FIG. 2 is a partially cutaway perspective view showing an internal configuration of a recording head in an embodiment of the present invention. FIG. 2 is a longitudinal side view illustrating a recovery device of the ink jet recording apparatus according to the embodiment of the present invention, in which (a) shows a state before the recovery operation, and (b) presses the capillary force generation unit against the nozzle to perform the recovery operation. Each state is shown. It is a vertical front view which shows the capillary force generation | occurrence | production part provided in the recovery apparatus in embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Recovery apparatus 2 Recovery apparatus member 3 Capillary force generating part 3a Upper porous member 3b Lower porous member 7 Silicon substrate 8 Nozzle 8a Ink ejection port 9 Nozzle partition wall 13 Top plate 14 Black recording head 15 Cyan recording head 16 Magenta Recording head 17 yellow recording head 18 recording medium 19 carry-out unit 20 supply unit 21 recording apparatus main body

Claims (14)

In an ink jet recording apparatus comprising a recovery means for discharging ink from a nozzle of the recording head and performing a recording operation by discharging ink from the nozzle provided in the recording head, and extracting and removing the thickened ink or foreign matter from the nozzle of the recording head.
The recovery means includes
An ink suction section for sucking ink by generating a capillary force larger than the nozzle of the recording head;
A moving means for moving the capillary force generating portion toward and away from the nozzle by relatively moving the nozzle and the capillary force generating member;
The ink jet recording apparatus, wherein the ink suction portion has a structure in which a capillary force increases in a direction away from the nozzle.   The ink jet recording apparatus according to claim 1, wherein the ink suction unit has a structure in which the density sequentially increases along a direction away from the nozzle when contacting the nozzle.   The ink suction portion is configured by a plurality of capillary force generation members that overlap in a direction away from the nozzle in a contact state with the nozzle, and the plurality of capillary force generation members are in the contact state with the nozzle. The ink jet recording apparatus according to claim 1, wherein a larger capillary distance is provided at a position where the distance from the head is larger.   The ink suction portion is configured by a plurality of capillary force generation members that overlap in a direction away from the nozzle in a contact state with the nozzle, and the plurality of capillary force generation members have a distance interval from the nozzle. 4. The ink jet recording apparatus according to claim 1, wherein the largest position has the maximum thickness.   4. The ink jet recording apparatus according to claim 1, wherein the capillary force generating member is a porous member having a gap smaller than a nozzle diameter of the recording head.   6. The ink suction unit according to claim 5, wherein porous members having different densities are polymerized, and each porous member is formed with a higher density as the distance from the nozzle increases. The ink jet recording apparatus described.   The ink jet recording apparatus according to claim 1, wherein the capillary force generating member is a thin tube having an opening diameter smaller than a nozzle diameter of the recording head.   8. The ink suction unit according to claim 7, wherein the ink suction unit includes a thin tube assembly in which the thin tubes are assembled, and the diameter of each thin tube is reduced in a direction away from the nozzle in a contact state with the nozzle. The ink jet recording apparatus described.   4. The capillary force generating member is made of an ink absorber formed by knitting fibers vertically and horizontally, and a gap smaller than the nozzle diameter is formed between the fibers. Inkjet recording apparatus.   The ink suction unit is formed by polymerizing a plurality of ink absorbers, and the gaps between the fibers of each ink absorber are sequentially reduced along the direction away from the nozzles when in contact with the nozzles. The inkjet recording apparatus according to claim 9, wherein   The capillary force generating member is composed of a wire assembly in which a large number of wires extending in a certain direction are assembled, and a minute gap formed between the wires is formed narrower than the diameter of the nozzle. An ink jet recording apparatus according to any one of claims 1 to 3.   12. The ink suction part according to claim 11, wherein the ink suction part sequentially reduces a minute gap formed between the wire members of the wire assembly in a direction away from the nozzle in a contact state with the nozzle. The ink jet recording apparatus described.   The ink jet recording apparatus according to claim 1, wherein the ink suction unit generates a capillary force along a vertical direction. In a recovery device that pulls out and removes thickened ink or foreign matter from the nozzles of the recording head used in the inkjet recording apparatus,
A capillary force generating member for generating a capillary force larger than the nozzle of the recording head;
Moving means for moving the capillary force generating member toward and away from the nozzle by relatively moving the nozzle and the capillary force generating member;
The recovery device according to claim 1, wherein the capillary force generating member has a structure in which the capillary force increases in a direction away from the nozzle.

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