JP4622401B2 - Inkjet recording device - Google Patents

Description

The present invention relates to an ink jet recording apparatus having a recording head for discharging droplets.

  An ink jet recording head generally includes a nozzle for discharging ink and an ink flow path communicating with the nozzle, and discharges ink from the nozzle by supplying energy to the ink in the ink flow path. .

  In such a nozzle, since the ink existing in the vicinity of the nozzle directly touches the atmosphere, the evaporation of the moisture of the ink is easily promoted, and the ink is relatively easily thickened. If ink thickening occurs in the nozzles and the like in this way, ejection failure such as deflection of the ink ejection direction and a decrease in the ejection amount, or if the degree of thickening is significant, the nozzles etc. increase. So-called clogging, which is blocked by viscous ink, may occur, resulting in non-ejection of ink.

  For this reason, the ink ejection state of the recording head is detected, and processing such as restoring the nozzle clogging state, substituting with another nozzle, or making the omission inconspicuous by image processing is performed according to the state. That is necessary to maintain image quality.

  On the other hand, in a recording apparatus having a size that allows the recording head to cover the recording medium width at a time, the number of nozzles is enormous. To check the ink ejection state of each nozzle, for example, as in Patent Document 1, check There is a method of printing a pattern for recording on a recording medium and visually confirming this, and in addition to this, a method of arranging a recording medium width sensor to read the pattern and confirming the ink ejection state, etc. Can be considered.

However, these methods require a recording medium every time the ink ejection state is checked, and the method of reading a pattern with a sensor for the recording medium width further requires the sensor, and the corresponding cost. Will be applied.
JP-A-5-338199

In consideration of the above-described facts, an object of the present invention is to provide an ink jet recording apparatus capable of checking the ink discharge state without using a recording medium.

In order to achieve the above object, the invention described in claim 1 includes a conveying belt that conveys a recording medium, a recording head that discharges droplets from nozzles to the recording medium, and an opening provided in the conveying belt. And a pattern recording member capable of printing droplets ejected from the nozzle through the opening, the pattern recording member being an endless belt, and the endless belt printing the pattern The printed surface is conveyed in the width direction of the conveyance belt perpendicular to the conveyance direction of the conveyance belt.

  According to the first aspect of the present invention, the opening is provided in the conveying belt for conveying the recording medium. Further, a pattern recording member is provided so that droplets ejected from the nozzle can be printed on the pattern recording member through the opening.

  Thus, by providing the pattern recording member and printing on the pattern recording member, it is possible to detect the ejection state of the nozzles. Further, by forming a pattern for detecting the ejection state of the nozzles on the pattern recording member, it is not necessary to use a recording medium conveyed by a conveying belt in order to form the pattern.

According to a second aspect of the invention, in the ink jet recording apparatus according to claim 1, wherein the opening, before obliquely to Ki搬 feeding direction, the beam portion connecting the long sides of the opening is provided It is characterized by that.

  In the invention according to claim 2, the conveying belt is reinforced by providing a beam portion that connects the long sides of the opening.

Here, when droplets are ejected from a nozzle disposed at a position facing the beam portion, the beam portion is contaminated by the droplet, but the beam portion is provided obliquely with respect to the conveyance direction of the conveyance belt. Therefore, when the transport belt is moved, the position of the nozzle facing the beam portion changes. Therefore, the position of the nozzle facing the beam portion is changed along with the movement of the transport belt, so that the liquid from all nozzles is not contaminated. Drops can be ejected.

According to a third aspect of the present invention, the opening is configured such that a plurality of rows formed by a plurality of small openings arranged along the width direction are arranged in the transport direction. The end portions in the width direction of the adjacent small openings overlap with each other in the transport direction.

In the third aspect of the invention, by arranging the small openings as described above and arranging the small openings in a staggered manner, the position of the nozzle corresponding to the small opening changes as the transport belt moves. Therefore, it is possible to discharge droplets from all the nozzles without polluting the conveyor belt.

The invention according to claim 4, in contact before Kimutan belt cleaning device for removing the printed pattern into an endless belt is characterized in that provided through the opening.

In the invention described in claim 4, the cleaning device, by removing the printed pattern to the endless belt, moving the endless belt, the endless belt is automatically clean.

The invention described in claim 5 is characterized in that a reading device for reading a pattern on the endless belt is provided.

In the invention according to claim 5, by providing a reading device that reads the pattern on the endless belt, when the endless belt is moved, the pattern is automatically read by the reading device, and the ejection state of the nozzle is mechanically detected. can do.

Further, by reading the pattern on the printing surface conveyed in the width direction of the conveying belt so that the discharge state of all the nozzles can be detected, the length of the reading device may be as long as the width of the nozzle surface. Therefore, the cost can be reduced as compared with the case where the pattern is read by a reading device having a length substantially the same as the length of the nozzle surface in the longitudinal direction.

  According to a sixth aspect of the invention, the recording head ejects droplets from the nozzle in a plurality of times to the opening portion whose position is changed by the movement of the conveying belt in the conveying direction.

In the invention according to claim 6, the droplets are ejected from the nozzle in a plurality of times to the opening whose position is changed by the movement of the conveyance belt in the conveyance direction so that the conveyance belt is not soiled. can do.

  According to a seventh aspect of the present invention, the recording head ejects droplets from the nozzles so that dots ejected from different adjacent nozzles among the dots forming the pattern do not overlap.

According to the seventh aspect of the invention, in the pattern formed on the endless belt, dots (ink) ejected from different adjacent nozzles are prevented from overlapping so that when the pattern is read by the reading device, the pattern is clear. As a simple image, it is easy to read, and the reading accuracy of the reading device can be lowered, and the cost can be reduced.

  Since the present invention is configured as described above, in the first aspect of the present invention, a pattern for detecting the discharge state of the nozzles is formed on the pattern recording member, so that the pattern is formed by the conveyance belt. There is no need to use a recorded recording medium.

  In the invention according to claim 2, the conveying belt is reinforced by providing a beam portion that connects the long sides of the opening. In addition, by providing the beam portion obliquely with respect to the recording medium conveyance direction, when the conveyance belt is moved, the position of the nozzle facing the beam portion changes. It is possible to discharge droplets from all nozzles without changing the position of the nozzles and fouling the beam portion.

  In the invention according to claim 3, by arranging the small openings in a staggered manner, the position of the nozzle corresponding to the small opening is changed along with the movement of the conveyance belt. Droplets can be ejected.

In the invention described in claim 4 , when the endless belt is moved by removing the pattern printed on the endless belt by the cleaning device, the endless belt is automatically cleaned.

In the invention according to claim 5, by providing a reading device that reads the pattern on the endless belt, when the endless belt is moved, the pattern is automatically read by the reading device, and the ejection state of the nozzle is mechanically detected. can do. Further, by reading the pattern on the printing surface conveyed in the width direction of the conveyance belt so that the discharge state of all the nozzles can be detected, the length of the reading device may be as long as the width of all the nozzles. Therefore, the cost can be reduced as compared with the case where the pattern is read by a reading device having a length substantially the same as the length of the nozzle surface in the longitudinal direction.

In the invention of claim 6, the droplets are discharged from the nozzle in a plurality of times to the opening whose position changes due to the movement of the conveyance belt in the conveyance direction so that the conveyance belt is not soiled. Can be.

According to the seventh aspect of the invention, in the pattern formed on the endless belt, dots (ink) ejected from different adjacent nozzles are prevented from overlapping so that when the pattern is read by the reading device, the pattern is clear. As a simple image, it is easy to read, and the reading accuracy of the reading device can be lowered, and the cost can be reduced.

  Hereinafter, an ink jet recording apparatus according to an embodiment of the present invention will be described.

  First, an outline of the ink jet recording apparatus 10 shown in FIG. 1 will be described. The recording medium is recording paper P, and the conveyance direction of the recording paper P is the main scanning direction. The ink jet recording apparatus 10 is a so-called FWA type ink jet recording apparatus that performs recording while transporting only the recording paper P while the recording head 12 is fixed.

  A driving roller 16 and a driven roller 18 constituting a main scanning mechanism are disposed at both ends in the main scanning direction of the ink jet recording apparatus 10, and a conveying belt 20 is bridged between the driving roller 16 and the driven roller 18. Has been. The driving force from the motor 24 is transmitted through the gear 22 connected to the driving roller 16 so that the conveying belt 20 rotates.

  The recording head 12 is disposed above the conveying belt 20 on the driving roller 16 side of the conveying belt 20, and ink is ejected from a plurality of nozzles 26 (see FIG. 4A) constituting the recording head 12. Ink is printed on the recording paper P transported by the transport belt 20.

  On the other hand, a transparent pattern belt 28 is disposed in the space formed by the conveying belt 20, and a driving roller 30 and a driven roller 32 are disposed at both ends. , It is laid over. The driving force from the motor 36 is transmitted through a gear 34 connected to the driving roller 30 so that the pattern belt 28 rotates.

  Incidentally, a substantially rectangular opening 38 (described later) is formed in the transport belt 20 so as to be able to face the recording head 12.

  In addition, a position detection device 44 including an optical transmitter 40 and an optical receiver 42 is disposed on the conveyor belt 20, and an opening 38 is disposed between the optical transmitter 40 and the optical receiver 42. Then, the light is received by the optical receiver 42. Thus, when a predetermined time determined from the conveyance speed of the conveyance belt 20 has elapsed, the opening 38 is disposed below the recording head 12.

  In this way, when the opening 38 is disposed below the recording head 12, ink is ejected from the nozzles 26 of the recording head 12, and the ejected ink is printed on the pattern belt 28 through the opening 38. .

  Here, in the opening portion 38, a beam portion 46 that bridges the long sides facing each other is formed so as to be inclined with respect to the conveying direction of the conveying belt 20, and the opening portion 38 is partitioned into a plurality of blocks. Thus, the opening 38 is divided into a parallelogram-shaped opening 38A and a trapezoidal opening 38B.

  As described above, by providing the beam portion 46 in the opening portion 38, when ink is ejected from the nozzle 26 (see FIG. 4A) disposed at a position facing the beam portion 46, the beam portion 46 is made of ink. As shown in FIGS. 2A to 2C, when the conveyor belt 20 is moved by inclining the beam section 46 with respect to the conveyance direction of the conveyor belt 20, as shown in FIGS. The position of the nozzle 26 facing 46 changes. For this reason, ink can be ejected from all the nozzles 26 without changing the position of the nozzles 26 that the beam portions 46 face with the movement of the conveying belt 20 and making the beam portions 46 dirty.

That is, as shown in FIG. 2A, ink is ejected from the areas A _{1 to} A ₃ of the nozzle 26 facing the openings 38A and 38B. When the transport belt 20 is moved, as shown in FIG. 2B, the area of the nozzle 26 facing the openings 38A and 38B increases, but the area B ₁ excluding the areas A _{1 to} A ₃ of the nozzle 26. the ink is ejected from ~B _3. Further, the transport belt 20 is moved, and ink is ejected from the region C of the nozzle 26. As a result, ink can be ejected from all the nozzles 26 without staining the beam portion 46 with ink.

  Here, the ink is ejected from the nozzles in three times, but it is sufficient if the ink can be ejected from all the nozzles 26 without soiling the beam portion 46 with the ink. It doesn't matter.

  Further, as shown in FIG. 3A, a plurality of openings 48A and openings 48B are arranged at predetermined intervals along a direction orthogonal to the conveyance direction of the recording paper P, and adjacent openings in the conveyance direction. The openings 48A and 48B may be arranged in a staggered manner so that the ends of the part 48A and the opening 48B overlap.

  As a result, as shown in FIG. 3B, ink is ejected from the region D of the nozzle 26 facing the opening 48A in a state where the opening 48A and a part of the nozzle surface 27 face each other. When the transport belt 20 is moved, as shown in FIG. 3C, the position of the nozzle 26 facing the opening 48A is shifted, so the position of the nozzle 26 is shifted in accordance with the movement of the transport belt 20 ( Ink is ejected while the area of the region D increases.

  Further, the transport belt 20 is moved, and ink is ejected from the region E of the nozzle 26 facing the opening 48B in a state where the opening 48B and a part of the nozzle surface 27 face each other. Then, ink is ejected while shifting the position of the nozzles 26 in accordance with the movement of the conveying belt 20 (while the area of the region E is widened). As a result, as shown in FIG. 3D, ink can be ejected from all the nozzles 26 without soiling the conveyor belt 20.

  On the other hand, as shown in FIGS. 1 and 6A, a reading device 50 is disposed above the pattern belt 28 on the drive roller 30 side of the pattern belt 28, and reading is performed below the pattern belt 28. A light source unit 52 is disposed corresponding to the device 50. The light source section 52 irradiates the pattern belt 28, and the image printed on the pattern belt 28 is read by the reading device 50.

  Here, as shown in FIG. 4A, when the nozzles 26 are arranged in a line, the nozzle pitch P becomes narrow, and when the ink 31 is discharged from all the nozzles 26 at the same time, as shown in FIG. As a result, the inks 31 overlap. This makes it difficult to detect nozzle defects such as non-ejection. Therefore, as shown in FIG. 4C, the nozzles 26 are thinned out, and printing is performed in a plurality of times, thereby detecting non-ejection of the nozzles 26.

  On the other hand, as shown in FIG. 5A, by arranging the nozzles 26 in a matrix (two-dimensional), the nozzle pitch in the longitudinal direction of the nozzle surface 27 is 4P (FIG. 4A). In the width direction of the nozzle surface 27, the nozzle pitch can be 2P.

  That is, while maintaining effective resolution as a two-dimensional head, the interval between the nozzles 26 on the ink jet recording head 32 can be increased, and ink 31 is ejected from all the nozzles 26 at once as shown in FIG. This makes it possible to print a pattern. For this reason, the non-ejection detection of the nozzle 26 can be performed once.

  On the other hand, as shown in FIGS. 1 and 7A, a cleaning device 54 composed of a rubber blade or the like is disposed on the downstream side of the reading device 50, and comes into contact with the pattern belt 28. The ink printed on the pattern belt 28 is scraped to clean the pattern belt 28.

  However, the present invention is not limited to this as long as the ink printed on the pattern belt 28 can be removed. For example, the felt 55 is brought into contact with the surface of the pattern belt 28 as shown in FIG. You may make it wipe off. For this reason, it is more effective to arrange the felt 55 at a position facing the drive roller 30. Further, the pattern belt 28 may be subjected to a surface treatment in order to improve printing removal performance.

  By the way, the reading device 50 is connected to a control unit (not shown), detects the ink discharge state of the nozzles 26 based on the data read by the reading device 50, and performs idle discharge or suction as necessary. For example, the clogged state of the nozzles 26 is recovered by other means, the other nozzles 26 are substituted, or the image processing is complemented.

  Next, the operation of the ink jet recording head according to the embodiment of the present invention will be described.

  As shown in FIG. 1, by forming a pattern for detecting the ejection state of the nozzle 26 on the pattern belt 28 through the opening 38, it is not necessary to use the recording paper P to form the pattern. Further, the conveyor belt 20 can be reinforced by providing the beam portion 46 that bridges the long sides of the opening 38 formed in the conveyor belt 20.

  Further, by inclining the beam portion 46 with respect to the conveyance direction of the recording paper P, the conveyance belt 20 is moved, and the position of the nozzle 26 facing the beam portion 46 is changed to eject ink. Liquid droplets can be discharged from all the nozzles 26 without polluting the beam portion 46.

  Further, the reading device 50 can detect the discharge state of all the nozzles 26 by reading the pattern on the pattern belt 28 provided along the direction orthogonal to the conveying belt 20, so that the reading device 50 can detect the width of the nozzle surface 27. Therefore, the cost can be reduced as compared with the case where the pattern is read by a reading device having a length in the longitudinal direction of the nozzle surface 27.

  Further, as shown in FIGS. 4A and 4B, when non-ejection of the nozzle 26 is detected, reading is performed by preventing the adjacent inks 31 from overlapping in the pattern formed on the pattern belt 28. When the pattern is read by the apparatus 50, it is easy to read as a clear image, and the reading accuracy of the reading apparatus 50 can be lowered, and the cost can be reduced.

  Of course, the present invention is not limited to this embodiment. For example, the pattern belt 28 for forming the pattern is bridged by the driving roller 30 and the driven roller 32, but it is sufficient that the pattern can be formed through the opening 38 formed in the conveying belt 20, so that the plate material is reciprocated. It is also possible to adopt a configuration such as

  In the present invention, as shown in FIG. 6A, the reading device 50 is provided above the pattern belt 28 and the light source unit 52 is provided below the pattern belt 28. Since it is sufficient that the pattern can be read, the present invention is not limited to this.

  For example, as shown in FIG. 6B, the arrangement of the reading device 50 and the light source unit 52 is reversed, the light source unit 52 is provided above the pattern belt 28, and the reading device 50 is installed below the pattern belt 28. It may be provided.

  Although the transparent pattern belt 28 has been described here, an opaque belt may be used. In this case, the light source unit 52 is disposed in the vicinity of the reading device 50 as shown in FIG. Become. Further, since the position of the reading device 50 may be on the upstream side of the cleaning device 54, the position shown in FIG.

  Further, the ink jet recording in the present invention is not limited to the recording of characters and images on the recording paper P. That is, the recording medium is not limited to paper, and the liquid to be ejected is not limited to ink. For example, the recording head 12 according to the present invention is applied to all industrially used liquid droplet ejecting apparatuses, such as creating a color filter for display by discharging ink onto a polymer film or glass. Can do.

1 is a perspective view showing an ink jet recording apparatus according to an embodiment of the present invention. (A)-(C) are explanatory drawings which show the ink discharge method of the recording head of the inkjet recording device which concerns on embodiment of this invention. (A), (B) is explanatory drawing which shows the modification of the ink discharge method of the recording head of the inkjet recording device which concerns on embodiment of this invention. (C), (D) is explanatory drawing which shows the modification of the ink discharge method of the recording head of the inkjet recording device which concerns on embodiment of this invention. (A)-(C) is an explanatory view showing the relationship between the arrangement of nozzles of the recording head of the ink jet recording apparatus according to the embodiment of the present invention and the ink ejection state. (A), (B) is explanatory drawing which shows the comparison with FIG. (A) is a layout view of the reading device and the light source of the ink jet recording apparatus according to the embodiment of the present invention, and (B) to (D) are modified examples of (A). (A) is explanatory drawing of the cleaning apparatus of the inkjet recording device which concerns on embodiment of this invention, (B) is a modification of (A).

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Inkjet recording device 12 Recording head 26 Nozzle 28 Pattern belt (pattern recording member, endless belt)
38 opening portion 46 beam portion 48A opening portion 48B opening portion 50 reading device 52 light source portion 54 cleaning device 55 felt (cleaning device)

Claims (7)

A conveying belt for conveying a recording medium;
A recording head for discharging droplets from nozzles to the recording medium;
An opening provided in the conveyor belt;
A pattern recording member capable of printing droplets ejected from the nozzle through the opening,
Have
The pattern recording member is an endless belt;
The endless belt is an ink jet recording apparatus in which a printing surface on which the pattern is printed is conveyed in the width direction of the conveyance belt perpendicular to the conveyance direction of the conveyance belt. The opening, before obliquely to Ki搬 feeding direction, the ink jet recording apparatus according to claim 1, wherein a beam portion connecting the long sides of the opening is provided.   The opening is formed by arranging a plurality of rows formed by a plurality of small openings arranged along the width direction in the transport direction, and the width in the small openings adjacent in the transport direction. The inkjet recording apparatus according to claim 1, wherein end portions in the direction overlap with the transport direction.   The inkjet recording apparatus according to any one of claims 1 to 3, further comprising a cleaning device that contacts the endless belt and removes a pattern printed on the endless belt through the opening.   The inkjet recording apparatus according to claim 1, further comprising a reading device that reads a pattern on the endless belt.   6. The recording head according to claim 1, wherein the recording head ejects liquid droplets from the nozzle in a plurality of times to the opening portion whose position is changed by movement of the transport belt in the transport direction. The ink jet recording apparatus described.   The said recording head discharges a droplet from the said nozzle so that the dot discharged from the adjacent different nozzle among the dots which form the said pattern may not overlap. Inkjet recording device.

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