JP2007245550A - Inkjet recording device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable it to prevent the deposition of a sticky ink formed in the retrieving domain of a waste ink by the means capable of making a device simpler and smaller than before. <P>SOLUTION: An inkjet recording device makes inks discharged from nozzles of a recording head 1 mounted in a carriage (not illustrated) which moves to and fro in the direction crossing against the direction of conveying a recording medium 5 and performs the recording on the recording medium 5. The inkjet recording device is equipped with a preliminary discharge receptacle 6 for receiving inks discharged preliminarily from the recording head 1 when the carriage has been arranged in a predetermined position. The preliminary discharge receptacle 6 has a slant face 6a inclined against a level surface to which inks discharged preliminarily from the recoding head 1 adheres. The inkjet recording device is also equipped with a heating element 8 for heating the slant face 6a. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an ink jet recording apparatus, and more particularly, to an ink jet recording apparatus used for a printer, a facsimile, or the like that performs recording by discharging ink.

  In this type of ink jet recording apparatus, for example, ink is supplied to the ink jet recording head from a cartridge-type ink tank filled with recording ink. Then, ink is ejected as recording droplets toward a recording material from an ejection port provided in the recording head, and recording is performed.

  In such an ink jet recording apparatus, dust and bubbles may be mixed in the ink supply system from the ink tank to the recording head. The ink discharge port provided in the recording head and the liquid path communicating with the ink discharge port generally have a very small inner diameter of about several μm to several tens of μm. For this reason, if dust or bubbles mixed in are guided to the liquid path of the recording head, they will adhere to the liquid path, obstructing the ink flow, reducing the ink discharge efficiency, or clogging in severe cases. There is a risk of causing a discharge failure. In addition, when ink is not ejected for a long time with the ink tank attached to the recording apparatus, the components constituting the ink may stick and cause abnormal ink ejection as well.

  In order to solve these problems, it is desirable to maintain ink discharge from the recording head in a good state during recording, and pressure recovery means, suction recovery means, and the like have been employed as recovery means for that purpose. It was. Among these, the suction recovery means sucks ink from the discharge port using a suction pump or the like while the peripheral portion of the ink discharge port of the recording head is closed with a cap, Obstacles such as bubbles and dust are removed from the liquid path.

  Also, in such an ink jet recording apparatus, in order to remove foreign matters that obstruct ink discharge such as ink and dust adhering to the discharge port surface of the recording head, the ink is discharged with a blade formed of an elastic body such as rubber. A wiping operation, which is a process of wiping and cleaning the exit surface, is performed.

  Furthermore, in order to prevent drying and sticking of nozzles that are not frequently used during recording, ejection as a recovery operation, that is, preliminary ejection operation is performed at regular intervals. In this case, ink is ejected from all the nozzles to a predetermined position outside the recording area at intervals (for example, every 20 seconds) at which the ink in the nozzles that are not ejected does not dry. In addition, preliminary discharge may be performed after the wiping operation for the purpose of stable discharge after wiping with a blade.

  The series of recovery means is generally performed by a recovery device including a cap, a suction pump, a blade, and the like provided outside the recording area of the recording head. Further, in the preliminary ejection operation, ink is generally ejected into a cap provided in the recovery device. However, when ink that is very easily fixed is used in a printer that performs bidirectional recording, stable ejection may not be ensured unless preliminary ejection is performed on both sides of the recording area during the recording operation. In this case, it is necessary to install preliminary discharge receptacles at a position on the recovery device side of the recording area and a position on the opposite side. As a conventional preliminary discharge receiving structure, a structure having a waste ink absorber disposed in a preliminary discharge area facing the recording head and allowing the predischarged ink to directly permeate the waste ink absorber is generally used. .

  However, in order to absorb a large amount of waste ink over a long period of time, the waste ink absorber needs a large waste ink absorber, and there is a problem that the recording apparatus itself becomes large. Furthermore, in recent years, various additives tend to be added to the ink in order to improve the image quality characteristics after recording of the liquid ink. For this reason, an ink that can shorten the speed at which the liquid ink is solidified and fixed (an ink having high fixability) has been used. In such highly fixable ink, viscosity increase or sticking occurs on the surface of the waste ink absorber before the ink itself is absorbed by the waste ink absorber. As a result, color materials such as pigments and dyes are deposited on the surface of the waste ink absorber, and the ink solvent remains between these color materials and continues to accumulate, resulting in a heaped state. When the preliminary ejection is performed, when the head moves to the preliminary ejection region, the ejection port surface of the recording head interferes with the ink accumulated in the piled state, causing the ejection port surface to be damaged and causing problems such as ejection failure. Sometimes.

As means for solving the above-mentioned problem, Patent Document 1 discloses that a certain amount or more of ink is discharged to a waste ink receiving portion by a method of breaking or dispersing using a mechanical operation member such as a gear, a gear pair, a scraper, or a shearing blade. It has been proposed to prevent height buildup.
Japanese Unexamined Patent Publication No. 7-251509

  However, this prior art configuration requires a mechanical working space for breaking the deposited ink, which complicates the configuration of the ink jet recording apparatus and leads to an increase in size.

  The present invention has been made in view of the above-described problems, and can prevent the thickened ink formed in the waste ink collecting area from being deposited by means that is simpler and more compact than before. An object is to provide an ink jet apparatus.

  In order to achieve the above object, an ink jet apparatus according to the present invention records on a recording medium by ejecting ink from nozzles of a recording head mounted on a carriage that reciprocates in a direction that intersects the conveyance direction of the recording medium. In the ink jet recording apparatus, the ink jet recording apparatus includes a preliminary discharge receiver that receives ink preliminarily discharged from the recording head. The preliminary ejection receiver has a slope portion inclined with respect to a horizontal plane to which ink preliminarily ejected from the recording head adheres, and further includes a heating means for heating the slope portion. Features.

  ADVANTAGE OF THE INVENTION According to this invention, the inkjet apparatus which can prevent accumulation of the thickened ink formed in a waste ink collection | recovery area | region with the means which can be reduced in size more simply than before can be provided.

  Next, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic perspective view showing an ink jet recording apparatus according to an embodiment of the present invention. FIG. 2 is a side view schematically showing the recording head and the preliminary ejection receiver and the surrounding structure in the ink jet recording apparatus shown in FIG.

  In the ink jet recording apparatus according to the present embodiment, a recording head 1 that records an image on a recording medium 5 by ejecting ink from a nozzle array on an ink ejection surface 2 is mounted on a carriage (not shown) that can move along a guide shaft 3. It is installed. The reciprocating movement of the recording head 1 is performed, for example, by a driving unit including a timing belt partially attached to the carriage and having pulleys wound around both ends and a carriage motor that rotationally drives one of the pulleys. As a result, the recording head 1 mounted on the carriage is reciprocated while being opposed to the recording medium 5. Further, the recording medium 5 is brought into pressure contact with a paper feed roller (not shown) and is conveyed by the rotation of the paper feed roller. Further, the recording medium 5 after recording is discharged out of the recording apparatus by a paper discharge roller (not shown). The conveyance direction of the recording medium 5 is a direction that intersects the reciprocating direction of the recording head 1.

  The recording head 1 is connected with ink tanks containing yellow, magenta, cyan, and black pigment inks, respectively, and an ink supply path extending from each ink tank is a nozzle row (not shown) provided in the recording element 4. Communicating with The nozzle rows are formed on the recording element 4 in a positional relationship such that they are aligned in a direction that intersects the carriage reciprocating direction. As the recording means by the recording element 4, if recording is performed by ejecting ink from a nozzle, a recording means that ejects ink using thermal energy, an electromechanical converter such as a piezoelectric element, and the like are used. Either recording means for ejecting ink may be used.

  A preliminary discharge receiver 6 is provided at a position opposite to the carriage home position across the conveyance path of the recording medium 5. On the other hand, a recovery device (not shown) is provided on the carriage home position side opposite to the preliminary discharge receiver 6. The recovery device prevents foreign matter such as paper dust attached to the ink discharge surface 2 of the recording element 4 and excess ink from being scraped off, covers the discharge surface 2 to prevent clogging of the discharge port, and prevents the recording head 1 from clogging. A cap and a pump for sucking ink from the nozzles of the ejection surface 2 are provided. The suction operation and the wiping operation by the recovery device are performed after replacement of the recording head 1, after a certain period of time during the recording operation, or when a recovery key on an operation panel (not shown) of the recording device is operated. Further, by performing preliminary ejection from the recording head 1 toward the preliminary ejection receiver 6 before and after the wiping operation or at regular intervals during the recording operation, the image quality of the recorded image can be stabilized.

  In the case where ink having high fixing properties is used, preliminary ejection is performed from the recording head 1 at positions on both sides of the conveyance path of the recording medium 5 during the recording operation. When performing preliminary discharge after the wiping operation or performing preliminary discharge on the home position side during the recording operation, the preliminary discharge is performed in the cap. Then, by driving the pump without covering the ejection surface 2 with the cap, the ink accumulated in the cap and the pump is discharged (empty suction operation).

  On the other hand, when preliminary ejection is performed on the side opposite to the home position during the recording operation, preliminary ejection is performed on the preliminary ejection receiver 6. The preliminary discharge receiver 6 is formed of resin integrally with the ink jet recording apparatus, and opens in a direction facing the discharge surface 2 of the recording head 1. In the region where the preliminarily ejected ink droplets first adhere directly, a slope portion 6a having an angle of about 45 ° with respect to the horizontal plane is provided, and below that is waste ink for storing the preliminarily ejected ink. A reservoir 7 is provided.

  Further, a heating element 8 is provided on the back surface of the inclined surface 6a to which ink droplets adhere. Although the heat generating body 8 may be in contact with the slope portion 6a or may not be in contact with the slope portion 6a, it is preferably in contact with the heat transfer efficiency. The heating element 8 is connected to a power source (not shown) in the ink jet recording apparatus, and the heating element 8 is appropriately set between the time when a recording signal is sent from a personal computer or the like (not shown) to the ink jet recording apparatus and the time when the recording operation is completed. It is controlled to be energized. The heating element 8 generates heat by energization, and the heat is conducted to the surface of the preliminary discharge receiver 6. The energy applied to the heating element 8 is controlled so that the surface of the inclined surface portion 6a of the preliminary discharge receiver 6 is about 40 ° C. Thus, when preliminary discharge is performed toward the slope portion 6a of the preliminary discharge receiver 6 during the recording operation, the slope portion 6a of the preliminary discharge receiver 6 is in a heated state.

  In general, as the temperature of a liquid such as ink increases, the viscosity decreases and the fluidity increases. Therefore, the ink 9 adhering to the inclined surface portion 6a of the preliminary ejection receiver 6 is heated and becomes highly fluid, and flows down along the inclined surface portion 6a and is stored in the waste ink storage portion 7. In this way, by performing preliminary ejection on the heated slope portion 6a, it is possible to prevent the thickened ink from remaining, adhering to the slope portion 6a, and being deposited. This prevents the deposited ink from interfering with the ejection surface 2 of the recording head 1 to cause recording failure.

  By heating at least the region where the pre-discharged ink adheres and the region through which the ink passes when the ink flows downward (gravity direction) from the inclined surface portion 6a of the pre-discharge receiver 6, It is possible to prevent the ink from sticking to the slope portion 6a. In addition, the water repellent treatment is performed on the surface of the slope portion 6a, thereby improving the ink flow-off property. Therefore, water repellent treatment may be performed, for example, with fluororesin or the like on both the regions of the slope portion 6a.

  In the present embodiment, the preliminary discharge receiver 6 is molded of resin integrally with the ink jet recording apparatus. However, the inclined portion 6 a of the preliminary discharge receiver 6 is more thermally conductive than the other portions of the preliminary discharge receiver 6. You may comprise with members, such as high metal. Thus, by constituting the slope portion 6a with a member having a relatively high thermal conductivity, the heat conduction efficiency from the heating element can be improved, and the energy consumption of the heating element can be reduced.

  In the present embodiment, the preliminary discharge receiver 6 has the inclined surface portion 6a. However, the preliminary discharge receiver 6 does not have the inclined surface portion 6a and has only the concave ink storage portion 7. Is also possible. In this case, preliminary ejection is performed toward the concave ink reservoir 7. However, in this configuration, since the distance until the ejected ink droplets land on the ink reservoir 7 becomes long, the ink droplets before landing float and diffuse as ink mist in the ink jet recording apparatus. There is a possibility that the harmful effect of soiling will occur. Therefore, it is preferable that the preliminary discharge receiver 6 has the inclined surface portion 6a as in the present embodiment. Further, in the present embodiment, as shown in FIGS. 1 and 2, by providing the preliminary discharge receiving portion 6 with the inclined surface portion 6a, a space is formed below the inclined surface portion 6a. A conveyance motor 10 for driving an unillustrated) is installed. As described above, by providing the inclined surface portion 6a in the preliminary discharge receiving portion 6, it is possible to arrange another part in the space below the preliminary discharge region, and thus the size of the ink jet recording apparatus can be reduced.

  In this embodiment, the temperature of the surface of the inclined surface 6a of the preliminary discharge receiver 6 is controlled to be about 40 ° C. However, if the temperature is too high, the solvent component of the ink evaporates and the viscosity of the ink is reversed. However, the fluidity decreases. FIG. 3 shows the distance (vertical axis) that each ink flowed down for 5 minutes after about 5 mg of each of the two types of inks A and B was dropped on the slope portion 6a of the preliminary discharge receiver 6 at an inclination angle of 45 °. It is a graph which shows the relationship with the surface temperature (horizontal axis) of the slope part 6a. The ink used in this embodiment is ink A.

  The composition of each ink is shown below.

Ink A
53% by weight of water
Cyan pigment 13% by weight
23% by weight of 1,3 butanediol
Glycerin 9% by weight
2-ethyl 1,3-hexanediol 2% by weight
Ink B
73% by weight of water
Magenta dye 6% by weight
Glycerin 10% by weight
Diethylene glycol 10% by weight
1% by weight of acetylenol
As can be seen from the graph, when the surface temperature of the slope portion 6a is 40 ° C. for both inks A and B, the distance that the ink flowed down is the longest, and this distance is the surface temperature of the slope portion 6a that does not heat the preliminary discharge receiver 6. Is about 1.7 times that at 25 ° C. On the other hand, when the surface temperature of the slope 6a rises to about 50 ° C., the solvent component of the ink evaporates, and the distance that the ink flows is shorter than when the surface temperature of the slope 6a is 25 ° C. The above experimental results are the results relating to the preliminary discharge receiver 6 of the present embodiment, and the optimum temperature of the slope portion 6a varies depending on the type of ink, the material of the slope portion 6a, the surface roughness, and the like. The set temperature is appropriately selected according to these factors.

  In the present embodiment, since the ink that has flowed into the waste ink storage unit 7 is configured to be thickened, fixed, and retained in the waste ink storage unit 7, a holding member such as a waste ink absorber is discarded. It is not installed in the ink reservoir 7. However, a holding member such as a waste ink absorber may be installed in the waste ink storage unit 7.

(Modification)
FIG. 4 is a view showing a modification of the ink jet recording apparatus shown in FIG. Unlike the configuration shown in FIG. 1 and the like, this modification does not have a dedicated heating element 8 for heating the preliminary discharge receiver 6. Instead, a conveyance motor 10 that drives a paper feed roller and a paper discharge roller (not shown) is used as a heat generating unit, and the conveyance motor 10 is disposed on the back side of the surface on which the ink is landed on the slope portion 6a. The conveyance motor 10 may be in contact with the surface on the back side of the surface on which the ink is landed on the inclined surface 6a, or may not be in contact with the surface, but is in contact with the heat transfer efficiency from the viewpoint. Is preferred.

  Since the paper feed roller and the paper discharge roller need to be rotated in order to transport the recording medium 5 during the recording operation, the transport motor 10 that rotates the roller is naturally driven. When the motor 10 is driven, the motor 10 itself generates heat with the loss energy of the motor as heat energy. Therefore, the transport motor 10 during the recording operation generates a considerable amount of heat, and the heat from the transport motor 10 is conducted to the inclined surface portion 6 a of the preliminary discharge receiver 6.

  Since the preliminary discharge to the preliminary discharge receiver 6 is performed during the recording operation, the preliminary discharge receiver 6 is heated as described above when preliminary discharge is performed to the preliminary discharge receiver 6. For this reason, the temperature of the ink preliminarily ejected to the preliminary ejection receptacle 6 is increased, the viscosity is decreased, and the fluidity is increased. Accordingly, as in the configuration shown in FIG. 1 and the like, the ink is liable to flow downward, so that it is possible to prevent the thickened ink from remaining on the slope portion 6a and sticking to the ink. Thus, by using the configuration in which the preliminary discharge receiver 6 is heated using the waste heat of the transport motor 10, the number of parts can be reduced compared to a configuration in which a heating element is separately provided, and the cost can be reduced. In addition, energy is saved because waste energy is used. In addition to the above configuration, if the inclined surface portion 6a of the preliminary discharge receiver 6 is made of a member having high thermal conductivity, or the surface of the inclined surface portion 6a is subjected to water repellent treatment, the ink is more likely to flow down, which is effective. It is. In this modification, the transport motor 10 is used as a heat generating means for heating the inclined surface portion 6 a of the preliminary discharge receptacle 6. However, the heat generating means for heating the inclined surface portion 6a may be any motor that generates heat by driving at least during the recording operation. For example, it may be a carriage motor that reciprocates the carriage.

1 is a schematic perspective view showing an ink jet recording apparatus according to an embodiment of the present invention. FIG. 2 is a side view schematically showing a recording head and a preliminary discharge receiver in the ink jet recording apparatus shown in FIG. 1 and a peripheral structure thereof. It is a graph which shows the relationship between the surface temperature of a slope part, and the distance which the ink flowed down. It is a figure which shows the modification of the inkjet recording device shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Recording head 2 Ink discharge surface 3 Guide shaft 4 Recording element 6 Preliminary discharge receptacle 6a Slope part 7 Waste ink storage part

Claims (6)

In an ink jet recording apparatus that performs recording on the recording medium by ejecting ink from nozzles of a recording head mounted on a carriage that reciprocates in a direction that intersects the conveyance direction of the recording medium.
A preliminary ejection receiver for receiving ink preliminarily ejected from the recording head, the preliminary ejection receiver having a slope portion inclined with respect to a horizontal plane to which the ink preliminarily ejected from the recording head adheres;
An ink jet recording apparatus, further comprising heat generating means for heating the inclined surface portion.   2. The ink jet recording apparatus according to claim 1, wherein the heat generating unit is in contact with a surface of the slope portion opposite to a surface to which ink preliminarily ejected from the recording head adheres.   2. The surface of the slope portion where the ink preliminarily ejected from the recording head adheres and the surface of the region where the ink passes when the ink flows down in the direction of gravity are subjected to water repellent treatment. Or the inkjet recording apparatus according to 2;   The slope portion is made of a member different from a member constituting a portion other than the slope portion of the preliminary discharge receptacle, and a thermal conductivity of a member constituting the slope portion is other than the slope portion of the preliminary discharge receptacle. The inkjet recording apparatus according to claim 1, wherein the inkjet recording apparatus has a thermal conductivity higher than that of a member constituting the portion.   5. The ink jet recording apparatus according to claim 1, wherein the heat generating unit is a motor installed in the ink jet recording apparatus and driven during a recording operation of the ink jet recording apparatus. The inkjet recording apparatus according to claim 5, wherein the motor is a conveyance motor that generates a driving force for conveying the recording medium or a carriage motor that generates a driving force for moving the carriage.

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