JP3135376U - Inkjet recording device - Google Patents

Abstract

An object of the present invention is to slow down the airflow in the vicinity of the nozzle of the ink head when performing sheet suction conveyance below the ink head, making ink droplets ejected from the nozzle less susceptible to the influence of the airflow, and generating mist and landing position misalignment. Suppress.
SOLUTION: A large number of air intake holes are provided, an endless transport belt 4 for transporting printing paper, and air is sucked from the back side of the transport belt through the air suction holes so that the printing paper is placed on the surface of the transport belt. In an ink jet recording apparatus including a suction fan 6 to be adsorbed on a print paper and an ink head 10 that discharges ink droplets from a nozzle to the print paper and records an image on the print paper, the ink jet recording apparatus is provided so as to surround an outer periphery of the ink head. An intake guide 11 having an upper end opening 12 through which air sucked into the suction fan flows, and a lower end opening 13 located near the nozzle and having a larger opening area than the upper end opening and through which air flowing in from the upper end opening flows out. Prepare.
[Selection] Figure 3

Description

  The present invention relates to an ink jet recording apparatus that records an image on a recording medium by ejecting ink droplets from nozzles of an ink head.

  In order to increase printing accuracy in an ink jet recording apparatus, it is necessary to keep the distance between the ink head and the printing paper (recording medium) constant. Therefore, below the ink head, the printing paper is conveyed in a state of being stuck on the conveying surface of the conveying belt.

  In this case, the conveyance belt that conveys the printing paper is provided with a large number of intake holes penetrating between the front surface and the back surface of the belt serving as a paper conveyance surface, and is sucked by a suction fan provided on the back surface side of the conveyance belt. By sucking air through the holes, the printing paper is adsorbed onto the conveying surface (the surface of the conveying belt).

  In the paper suction conveyance as described above, the suction force by the suction fan is further increased, so that even distorted and deformed printing paper is conveyed flatly, and the distance between the ink head and the printing paper is constant. Can be printed with high accuracy. Further, the deformed printing paper does not collide with the ink head.

  However, when the sheet is sucked and conveyed under the ink head, the air flow around the nozzles for ejecting ink droplets becomes faster because the suction fan sucks air around the ink head. As a result, the ink droplets flying between the ink head (nozzles) and the printing paper are affected by the air flow, which may cause mist (scattering of satellite droplets attached to the main droplets) and landing position deviation. there were.

  In addition, the ink jet recording apparatus disclosed in Patent Document 1 described below reduces inward airflow with respect to the arrangement direction of a plurality of arranged discharge ports in a space sandwiched between the discharge ports of the recording head and the recording medium. Airflow control means is provided.

As shown in FIG. 6A, on both sides of the recording head unit 100 in the sub-scanning direction, a bar 101 extends along the main scanning direction so as to sandwich the recording head unit 100. Further, the rod 101 is provided with a wire 102 protruding in the radial direction. The bar 101 rotates in the direction of the arrow in FIG. 5B as the recording head unit 100 advances in the main scanning direction. As the bar 101 rotates, the wire 102 rotates, and an outward airflow is generated. In Patent Document 1 below, it is verified that the airflow that causes the landing position deviation of the ink droplets is a drawing flow (inward airflow) from both ends in the arrangement direction of the discharge ports, and the drawing flow is outside. It is described that it is offset by the airflow in the direction, and as a result, the landing position deviation of the ink droplet can be suppressed.
Japanese Patent Laid-Open No. 2005-7660

  However, in order to perform airflow control (see FIG. 6) as in the ink jet recording apparatus disclosed in Patent Document 1, a drive source for rotating the bar 101 is required, and further, the bar 101 has a radial direction. There is a problem that the configuration is complicated, for example, the protruding wire 102 is provided.

  Further, for example, even when the outward airflow is faster than the entrainment flow (inward airflow), the landing position deviation of the ink droplets is generated, and therefore the outward flow is sufficient to cancel out the entrainment flow that causes the landing position deviation. Setting the rotation speed of the bar 101 so as to generate an air current is not a little troublesome.

  Therefore, in order to solve the above problems, the present invention slows the air flow in the vicinity of the nozzles of the ink head with a simple configuration that does not require a drive source when the recording medium is sucked and conveyed below the ink head. Accordingly, an object of the present invention is to provide an ink jet recording apparatus in which ink droplets ejected from a nozzle are not affected by an air current, and mist and landing position deviation are suppressed.

Next, means for solving the above problems will be described with reference to the drawings corresponding to the embodiments.
The ink jet recording apparatus according to claim 1 of the present invention is provided with a plurality of air intake holes 5 penetrating between the front surface and the back surface, and an endless transport belt 4 for transporting the recording medium P;
A suction fan 6 for sucking the recording medium P onto the surface of the transport belt 4 by sucking air from the back surface side of the transport belt 4 through the intake holes 5;
In an ink jet recording apparatus comprising: an ink head that ejects ink droplets from nozzles to the recording medium P conveyed by the conveying belt 4 to record an image on the recording medium P;
Provided around the outer periphery of the ink head 10;
An upper end opening 12 through which air sucked into the suction fan 6 flows;
The intake guide 11 includes a lower end opening 13 that is located in the vicinity of the nozzle and has an opening area larger than that of the upper end opening 12 and through which air flowing in from the upper end opening 12 flows out.

  According to such a configuration, air flows from the upper end opening 12 of the intake guide 11 and flows out from the lower end opening 13. At this time, since the inflow flow rate of air per unit time in the upper end opening 12 and the outflow flow rate per unit time in the lower end opening 13 are the same amount according to the law of constant flow rate, the inflow rate of air in the upper end opening 12 is fast. However, the outflow speed of the lower end opening 13 is slow. That is, the airflow near the nozzle from which the ink droplets are ejected becomes slow. As a result, the ink droplets ejected from the nozzles are not affected by the air current, and mist and landing position deviation do not occur.

  The ink jet recording apparatus according to claim 2 is characterized in that an opening area ratio between the upper end opening 12 and the lower end opening 13 in the intake guide 11 is adjusted.

  According to such a configuration, for example, when it is desired to further slow down the airflow in the vicinity of the nozzle, the user uses the intake guide 11 of the lower end opening 13 having a larger opening area. By selecting it, the air flow near the nozzle can be made to an optimum speed.

  The ink jet recording apparatus according to claim 3 is characterized in that the suction fan 6 further speeds up the air flow outside the intake guide 11.

  According to such a configuration, the suction force with respect to the recording medium P can be increased while the airflow in the vicinity of the nozzle is slow.

The ink jet recording apparatus according to claim 4, wherein the ink head 10 is a line head type ink jet recording apparatus in which the ink heads 10 are arranged in a direction orthogonal to the transport direction X of the transport belt 4.
The intake guide 21 is provided so as to surround the outermost periphery of the line head 20.

  According to such a configuration, the airflow in the vicinity of the nozzles of all the ink heads 10 forming the line head 20 can be delayed by only one intake guide 21.

  According to the ink jet recording apparatus of the present invention, the air flow in the vicinity of the nozzle from which ink droplets are ejected is slowed by simply attaching an intake guide having a simple configuration to the ink head. For example, even if the suction force is increased for suction conveyance, The ink droplets are not affected by the air flow, and the occurrence of mist and landing position deviation can be suppressed, and the printing accuracy is improved.

Embodiments of the present invention will be specifically described below with reference to the drawings.
1 is a plan view showing a recording portion of an ink jet recording apparatus according to the present invention, FIG. 2 is a perspective view of an ink head provided in the ink jet recording apparatus, FIG. 3 is a cross-sectional view taken along line AA in FIG. FIG.

  The ink jet recording apparatus of this embodiment is a line head type ink jet recording apparatus in which the ink heads are arranged in a staggered manner along the direction (main scanning direction) orthogonal to the transport direction of the transport belt described later for each color. .

  As shown in FIGS. 1 and 3, a recording unit 1 for performing an image recording process in an ink jet recording apparatus includes a paper transport unit 2, a suction fan 6, and an ink head 10.

  As shown in FIG. 3, the paper transport unit 2 includes a plurality of rollers 3 and a transport belt 4 that is wound around the rollers 3. The plurality of rollers 3 are provided between the pair of rollers 3 a and 3 b provided side by side in the transport direction X and the pair of rollers 3 a and 3 b, and a roller 3 c for applying tension to the transport belt 4. It consists of. Of the pair of rollers 3a and 3b, one of the rollers 3a (3b) is a drive roller connected to a drive motor (not shown), and the other roller 3b (3a) is a driven roller.

  As shown in FIG. 1, the above-described transport belt 4 is an endless belt, and is provided with a large number of air intake holes 5 penetrating between the front surface and the back surface of the print paper (recording medium) P. Yes. The transport belt 4 rotates in the transport direction X by the rotation of the rollers 3a to 3c to which power is transmitted from the drive motor, and transports the printing paper P in the transport direction X.

  As shown in FIG. 3, a plurality of (three in the figure) suction fans 6 are provided in the transport direction X on the back side of the transport belt 4. The suction fan 6 sucks air through the suction holes 5 of the transport belt 4 to adsorb the printing paper P transported by the transport belt 4 onto the surface of the belt 4.

  As shown in FIGS. 1 and 3, the ink head 10 is provided on the paper transport surface (front surface) of the transport belt 4. In addition, nozzles (not shown) that selectively eject ink droplets are arranged in the ink head 10 so as to face the printing paper P on the surface of the conveyor belt 4 while being arranged at a predetermined pitch. Further, as shown in FIG. 1, the ink head 10 is arranged in a direction (main scanning direction) orthogonal to the transport direction X for each color of black (K), cyan (C), magenta (M), and yellow (Y). A line head 20 is formed by being arranged in a zigzag pattern.

  As shown in FIG. 2, each ink head 10 is provided with a substantially cylindrical intake guide 11 surrounding the outer periphery of the ink head 10 so as to accommodate the ink head 10 therein. The intake guide 11 has an upper end opening 12 and a lower end opening 13. Of these, the upper end opening 12 is formed to have a diameter slightly larger than the outer shape of the ink head 10, and the lower end opening 13 is an upper end opening. The opening area is larger than 12. The inside of the intake guide 11 is gradually widened from the upper end opening 12 to the lower end opening 13, and when the intake guide 11 is attached to the ink head 10, the lower end opening 13 is positioned near the nozzles of the ink head 10. . The intake guide 11 can be easily attached to and detached from the ink head 10. In addition, if several types are prepared by adjusting the opening area ratio between the upper end opening 12 and the lower end opening 13, the user can select the intake guide 10 appropriately according to the printing conditions.

Hereinafter, the flow of air around the ink head in the sheet suction conveyance will be described with reference to FIG.
As shown in FIG. 4, around the ink head 10, air sucked by the suction fan 6 (see FIG. 3) flows into the intake guide 11 from the upper end opening 12. Then, the air flowing into the intake guide 11 flows out from the lower end opening 13 and flows to the back side of the belt 4 through the intake holes 5 of the conveyor belt 4. At this time, since the inflow flow rate of air per unit time in the upper end opening 12 and the outflow flow rate of air per unit time in the lower end opening 13 are the same by the constant flow rate, the upper end opening 12 having a small opening area On the contrary, the flow of air is slow, and the flow is slow in the lower end opening 13 having a large opening area. As a result, the ink droplets ejected from the nozzles are not affected by the airflow by the lower end opening 13, and mist, landing position deviation, and the like do not occur.

  Further, between the adjacent ink heads 10, 10, the closer to the sheet conveyance surface (front surface) of the conveyance belt 4, the narrower the air flow path becomes due to the lower end openings 13, 13 of the respective intake guides 11, 11. The flow becomes faster. As a result, a secondary effect of increasing the suction force for sucking and conveying the paper is also obtained. Further, by further increasing the flow of air around the ink head 10 by the suction fan 6, only the suction force can be increased while the airflow in the vicinity of the nozzle is slow.

  In the above-described embodiment, the intake guide 11 is provided for each ink head 10. However, as shown in FIG. 5, the plurality of ink heads 10 are orthogonal to the transport direction X (main scanning direction). In the line head type ink jet recording apparatus arranged in a zigzag pattern along the head), an air intake guide 21 surrounding the outermost periphery of the entire ink head 10 forming the line head 20 may be provided. As shown in the figure, also in this intake guide 21, since the opening area of the lower end opening 13 is larger than the upper end opening 12, the air flow in the lower end opening 13 becomes slow, and the ink droplets ejected from the nozzles are affected by the air flow. There will be nothing. As a result, in addition to being able to suppress the occurrence of mist and landing position deviation as described above, it is only necessary to provide one intake guide 21 for all the ink heads 10 forming the line head 20, and the configuration is further simplified. There is also an effect that the

It is a top view which shows the recording part of the inkjet recording device by this invention. It is a perspective view which shows the air intake guide with which the same inkjet recording device is provided. It is AA sectional drawing in FIG. FIG. 4 is a partially enlarged view of FIG. 3. It is a perspective view which shows the air intake guide with which the inkjet recording device of other embodiment by this invention is provided. (A), (b) It is a figure which shows the airflow control in the conventional inkjet recording device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 4 ... Conveyance belt 5 ... Intake hole 6 ... Suction fan 10 ... Ink head 11, 21 ... Intake guide 12 ... Upper end opening 13 ... Lower end opening 20 ... Line head P ... Printing paper as a recording medium X ... Conveyance direction

Claims (4)

A large number of air intake holes penetrating between the front surface and the back surface, and an endless transport belt for transporting the recording medium;
A suction fan for adsorbing the recording medium onto the surface of the transport belt by sucking air from the back surface side of the transport belt through the intake holes;
In an ink jet recording apparatus comprising: an ink head that discharges ink droplets from nozzles to the recording medium conveyed by the conveying belt to record an image on the recording medium;
Provided around the outer periphery of the ink head;
An upper end opening through which air sucked into the suction fan flows,
An ink jet recording apparatus comprising: an air intake guide that is located in the vicinity of the nozzle and has a larger opening area than the upper end opening, and a lower end opening through which air flowing in from the upper end opening flows out.   2. The ink jet recording apparatus according to claim 1, wherein an opening area ratio between the upper end opening and the lower end opening in the intake guide is adjusted.   3. The ink jet recording apparatus according to claim 1, wherein the suction fan further accelerates the flow of air outside the intake guide. In the line head type ink jet recording apparatus in which the ink heads are arranged in a direction orthogonal to the transport direction of the transport belt,
The inkjet recording apparatus according to claim 1, wherein the intake guide is provided so as to surround an outermost periphery of the line head.

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