JP2016084227A - Inkjet recorder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inkjet recorder which prevent the generation of bubbles on a belt, removes an ink, fuzz, yarn wastes or the like adhering on the belt, and can stabilize the quality of a printed product.SOLUTION: The inkjet recorder which discharges inks, and can record an image on a recording medium 61 comprises recording means 20 in which nozzles for discharging inks are formed, and an endless belt 11 arranged at a lower side of the recording means. The inkjet recorder also comprises: transport means 10 which rotates the endless belt to one direction, and makes the recording medium which is set on a transport face formed at an external peripheral face of the endless belt pass to the recording means from one end side, and in which a feed path for transportation to the other end side and a return path including a range in which the endless belt moves to one end side from the other end side are formed; and washing means 30 composed of a first cleaning part 31 which cleans the external peripheral face of the endless belt at the return path, and a second cleaning part 32 which is arranged at a downstream position of the first cleaning part. Each cleaning part has washing rollers 33, 34, and can independently adjust rotation numbers of the washing rollers.SELECTED DRAWING: Figure 1

Description

The present invention relates to an ink jet recording apparatus that forms an image by ejecting ink onto a recording medium, and more particularly to an ink jet recording apparatus that includes a cleaning unit for cleaning an endless belt that supports the recording medium.

In Patent Document 1, a plurality of cleaning rollers are provided that can be pressed against the conveyor belt and that cleans the conveyor belt. In addition, a cleaning liquid for removing dirt attached to each cleaning roller is stored, and each cleaning roller is immersed in the cleaning liquid. There is disclosed an invention in which a plurality of cleaning water tanks are provided, and waste liquid that can no longer be used as cleaning liquid in the downstream cleaning water tank is used as cleaning liquid in the upstream cleaning water tank.

However, when a large amount of ink stains remain on the belt, the cleaning roller in the first tank first drops it, so that a large amount of ink is mixed into the cleaning liquid. At this time, the cleaning roller of the first tank is immersed in the cleaning water of the cleaning water tank, and the cleaning liquid containing a large amount of ink is stirred by the cleaning roller.
For this reason, if the ink contains a chemical that easily generates bubbles, such as a surfactant, a large amount of bubbles are generated.

  The speed of the conveying device also affects the generation of bubbles. If the transport speed is slow, it takes time until the next recording, so it can be washed slowly and without foaming. However, if the transport speed is fast, the belt must be cleaned quickly before the next recording operation, so bubbles tend to form. An environment is born.

Further, it greatly depends on the form of the recording medium. In a medium having many voids such as a fabric, the ink ejected on the surface tends to pass through. That is, the conveyor belt is easily soiled. If the amount of dirt is large, the cleaning means must scrape a large amount of ink, which inevitably increases the generation of bubbles. In the prior art, bubbles overflow to the back of the belt and the outside of the tank, the apparatus and its surroundings become dirty, and the back of the belt rotates around the belt surface as the belt rotates, and eventually the fabric is soiled.

JP 2005-212277 A

The present invention has been made to solve the above-described problems, and can prevent bubbles from adhering to the belt and reliably remove the ink adhering to the belt. An object of the present invention is to provide an ink jet recording apparatus that enables stable quality.

An ink jet recording apparatus according to the present invention is an ink jet recording apparatus capable of recording an image on a recording medium by ejecting ink, and a recording unit in which a nozzle for ejecting the ink is formed, and a lower side of the recording unit. An endless belt is provided, and the endless belt is rotated in one direction so that the recording medium set on the conveying surface formed on the outer peripheral surface of the endless belt is passed through the recording means from one end side. Conveying means in which a feed path for conveying to the end side, a return path including a range in which the endless belt moves from the other end side to the one end side, and the outer periphery of the endless belt in the return path A first cleaning section for cleaning the surface and a cleaning means comprising a second cleaning section disposed at a downstream position of the first cleaning section, each of the cleaning sections has a cleaning roller, and the rotation of the cleaning roller The number is configured to be adjusted individually.

In addition, the present invention has the following characteristics. The first cleaning unit and / or the second cleaning unit includes a suction device.

Furthermore, it is preferable that α <β, where α is the rotational speed of the cleaning roller of the first cleaning section and β is the rotational speed of the cleaning roller of the second cleaning section.

According to the present invention, a plurality of cleaning units are provided, and the number of rotations of the cleaning roller of each cleaning unit can be adjusted independently, so that the first cleaning unit can perform maximum ink cleaning while suppressing the generation of bubbles. The ink speed can be adjusted, and ink remaining on the endless belt can be removed by wiping off the remaining ink at the second cleaning section.
Furthermore, in the drainage port of the first cleaning unit and / or the second cleaning unit, when natural drainage alone does not have sufficient drainage capacity, and bubbles do not fall off, bubbles can be generated in the cleaning unit by providing a foam suction device. The generation of bubbles can be suppressed without accumulating.

1 is a schematic configuration diagram illustrating an example of an image recording apparatus according to the present invention. It is a schematic block diagram which shows a part of washing roller which concerns on this invention. It is a schematic block diagram which shows an example of the suction device which concerns on this invention

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. The present invention is not limited to the configurations described below, and various configurations can be employed in the same technical idea. For example, some of the configurations shown below may be omitted or replaced with other configurations. Other configurations may be included.
FIG. 1 is a schematic configuration diagram illustrating an example of an ink jet recording apparatus 1 according to the present invention. The ink jet recording apparatus 1 includes a transport unit 10, a recording unit 20, and a cleaning unit 30.
In the conveying means 10, an endless belt having a predetermined width is stretched across a plurality of (two in FIG. 1) pulleys 15 arranged in parallel at a predetermined interval.
The upper surface of the endless belt 11 spanned between the pulleys 15 is a mounting surface on which the recording medium 60 is placed in close contact.
One pulley is a main driving pulley 12 connected to a sub-scanning motor (not shown) so as to be able to transmit a driving force, and the other pulley is a driven pulley 13. The main driving pulley 12 is driven by the rotational driving of the sub-scanning motor in FIG. By rotating at a predetermined speed in the direction of arrow c (counterclockwise), the endless belt 11 spanned between the driven pulley 13 is rotated and the recording medium 60 placed on the upper surface of the endless belt 11 is rotated. The sheet is conveyed in the scanning direction a direction in the figure.

As the recording medium 60, for example, a recording medium usually used for ink jet recording, such as paper, fabric, and plastic film, can be used.
The recording medium 60 may be in the form of a sheet cut to a predetermined size, or may be in the form of a long sheet that is continuously fed out from the original winding wound in a roll shape.
In particular, since the fabric has a large number of voids and ink can easily pass through, there is a high possibility that a large amount of ink will adhere to the surface of the endless belt 11, and a particularly remarkable effect can be obtained by providing the cleaning means 30 described later. Hereinafter, the recording medium 60 will be described based on the example of the fabric 61.

The endless belt 11 as a fabric support is wound around the main pulley 12 and the driven pulley 13 and rotates in the direction of the arrow c. An adhesive layer (not shown) is formed on the surface of the endless belt 11, and a constant tension is applied to the endless belt 11 by a tension mechanism (not shown).

On the feed side of the endless belt 11, a pressing roller 14 is provided for the driven pulley 13, and the fabric 61 is inserted between the pressing roller 14 and the receiving portion 16.

The fabric 61 on which the image is printed is fed out from a roll (not shown), inserted between the pressing roller 14 and the receiving portion 16, and pressed by the pressing roller 14 with a certain pressure so as not to cause wrinkles, It is adhesively fixed to the surface of the endless belt 11.

The cloth 61 adhered and fixed to the endless belt 11 is transported to the feeding side integrally with the endless belt 11, and ink is applied to the cloth 61 by the ink jet head 21 which is the recording means 20 provided at an appropriate position in the middle. Is granted. The ink-jet head 21 is mounted on a carriage (not shown) disposed at a predetermined interval above the surface on which the fabric 61 is placed. The ink-jet head 21 discharges and the endless belt 11 rotates and moves. According to the timing, ink is applied by sequentially ejecting ink droplets from a large number of nozzles (not shown) provided on the lower surface of the fabric 61 on the endless belt 11, and a desired image is printed.

The inkjet head 21 may be a serial type recording unit that reciprocates in the main scanning direction orthogonal to the conveyance direction of the recording medium 60 that is intermittently conveyed, or is fixed across the width direction of the endless belt 11. It may be a line-type recording unit that records an image by ejecting ink droplets onto a recording medium 60 that is stretched over and continuously conveyed.

When the printing of the image on the fabric 61 is finished, the fabric 61 is peeled off from the endless belt 11 near the main pulley 12, is pulled away in the direction of the arrow b, and is wound on a roll (not shown) after the drying process.

Since the surface of the endless belt 11 after the printed fabric 61 is peeled off is ink, fluff, lint, etc. as described above, the d direction on the return side of the endless belt 11 is used to remove these. The cleaning means 30 is provided at an appropriate position.

In the present invention, the cleaning means 30 is provided in the return path of the conveying means 10 and is disposed in the vicinity of the main pulley 12 in this embodiment.
The cleaning means 30 is provided with a plurality of cleaning sections (first cleaning section 31 and second cleaning section 32) in order along the moving direction of the endless belt 11.
The first cleaning unit 31 includes a cleaning roller (1) 33, a cleaning pipe 35, a wiping blade (1) 36, and a cleaning tank (1) 38. In order to efficiently remove the dirt on the washing roller (1) 33 and the dirt on the endless belt 11, it is preferable to have the washing pipe 35 and the wiping blade (1).
The second cleaning unit 32 includes a cleaning roller (2) 34, a wiping blade (2) 37, a cleaning water storage tank 40, and a cleaning tank (2) 39. In order to efficiently remove the dirt on the endless belt 11 and the dirt on the washing roller (2) 34, it is preferable to have a wiping blade (2) 37 and a washing water storage tank 40.

The cleaning pipe 35 of the first cleaning unit 31 is stretched over the entire width of the endless belt 11, and a number of nozzles (not shown) are provided along the length direction at a portion facing the surface of the endless belt 11. Are arranged.
For example, industrial water is pumped to the cleaning pipe 35, and the pumped industrial water is sprayed from the nozzle toward the cleaning roller (1) 33.
The tip of the cleaning roller (1) 33 is always in contact with the surface of the endless belt 11, and is rotated at a predetermined speed in a direction opposite to the moving direction of the endless belt 11 by a drive motor (not shown). The surface of 11 is rubbed, and the ink adhering to the surface of the endless belt 11 is washed.

Incidentally, as shown in FIG. 2, in the case where the brush bristles 45 are spirally implanted around the rotary shaft 44 spanning the entire width of the endless belt 11 in the cleaning roller 48, the brush pitch 46, the channel Depending on the width 47, the ratio of the area where the brush bristles 45 contact the endless belt 11 while the cleaning roller 48 makes one rotation changes.
For example, when the brush pitch is 12 mm and the channel width is 5 mm, the area ratio occupied by the channel is 42%.
Even if the endless belt 11 side is stopped, if the brush bristles 45 cannot be completely contacted with the endless belt 11 unless it is rotated about 2.4 times, the dirt of the endless belt 11 is completely removed. It is necessary to rotate the cleaning roller 48 at high speed.
Further, as the number of rotations of the cleaning roller 48 is higher, the area where the brush bristles 45 contact the endless belt 11 per unit time increases.
As described above, the higher the rotation speed of the cleaning roller 48, the higher the ability to remove ink attached to the endless belt 11. Here, the diameter of the cleaning roller 48 is preferably about 70 to 130 mm in consideration of the ink scraping ability.

It is preferable that the drainage liquid containing a large amount of ink scraped off by the cleaning roller (1) 33 is immediately discharged without being stored in the cleaning tank (1).
In the case of a thin fabric or a coarse fabric, when ink droplets are ejected onto the fabric 61 by the recording means 20, not all of the ink stays on the fabric 61, but penetrates onto the endless belt 11 below it. End up.
In this case, if the amount of ink scraped off by the cleaning roller (1) 33 of the first cleaning unit 31 is excessive, the ink adhering to the cleaning roller (1) 33 and the cleaning water or the sewage collected in the cleaning tank (1) 38 However, since it is agitated by the rotation of the cleaning roller (1) 33, a large amount of bubbles are generated in proportion to the amount of ink contained in the sewage and the rotational speed of the cleaning roller (1) 33.

Therefore, the rotation speed of the cleaning roller (1) 33 of the first cleaning unit 31 is set to a rotation speed α (rpm) at which bubbles are not generated from the back-through ink attached to the endless belt 11. Here, α is preferably about 30 to 60 rpm.
In this state, the ink adhering to the endless belt 11 is not completely removed, and as it is, the placed fabric 61 is contaminated with ink that could not be removed. Therefore, the second cleaning unit 32 is installed for the purpose of removing ink that could not be removed by the first cleaning unit 31.

The cleaning roller (2) 34 is formed in a roller shape by, for example, brush bristles 45 being planted around a rotating shaft that spans the entire width of the endless belt 11. A part of the cleaning roller (2) 34 is immersed in the cleaning water tank 40, and the cleaning water tank 40 is always replenished with a certain amount of cleaning water (for example, industrial water).
The tip of the cleaning roller (2) 34 is always in contact with the surface of the endless belt 11, and is rotated at a predetermined speed in a direction opposite to the moving direction of the endless belt 11 by a drive motor (not shown). The surface of 11 is rubbed, and the ink adhering to the surface of the endless belt 11 is washed.

The rotational speed of the cleaning roller (2) 34 of the second cleaning unit 32 is such that the cleaning roller (2) 34 contacts the endless belt 11 per unit time in order to reliably remove the ink remaining on the endless belt 11. Rotate at high speed to increase area. This number of rotations is β (rpm). At this time, since most of the ink adhering to the endless belt 11 has been removed by the first cleaning unit 31, a large amount of bubbles are not generated even if the rotational speed β (rpm) is high, and dirt is removed. It is possible to increase the rotational speed to be removable. Here, as β, about 100 to 160 rpm is preferable.
Thereby, the ink that could not be removed by the first cleaning unit 31 can be removed by the second cleaning unit 32.
At this time, the rotational speed of the cleaning roller (2) 34 of the second cleaning unit 32 is made faster than the rotational speed of the cleaning roller (1) 33 of the first cleaning unit 31 so that the rotational speed β> the rotational speed α. It is a point.
Therefore, it is necessary that the number of rotations of the cleaning roller 48 can be adjusted individually. In order to realize this, for example, an inverter circuit for driving the cleaning roller (1) 33 and the cleaning roller (2) 34 is individually provided so that the rotational speed can be adjusted individually.

In the present embodiment, the wiping blade (1) 36 and the wiping blade (2) 37 are disposed on the first cleaning unit 31 and the second cleaning unit 32, respectively, but the wiping blade (2) of the second cleaning unit 32 is provided. In order to remove water droplets that could not be removed at 37, a water absorption roll 41 is provided on the downstream side of the second cleaning unit 32.
In addition, in order to suppress generation | occurrence | production of a foam in each cleaning part, each drain outlet (1) 42 and drain outlet (2) 43 of the 1st cleaning part 31 and / or the 2nd cleaning part 32 are like FIG. It is preferable to attach the suction device 50 and suck the sewage and bubbles. By attaching the suction device 50, it is possible to reduce the contamination of the endless belt 11 even if some bubbles are generated.

The suction device 50 is installed below the cleaning roller 48 as shown in FIG. Here, it is installed in the first cleaning unit 31. The suction device 50 includes a suction pipe 51, a separator 52, a filter 53, a blower 54, and a waste liquid port 55. Not only the 1st cleaning part 31 but you may install in the 2nd cleaning part 32, and you may install in both the 1st cleaning part 31 and the 2nd cleaning part 32.

In the cleaning means 30 configured as described above, the cleaning roller 48 spanned in the width direction of the endless belt 11 by a drive motor (not shown) repeatedly brushes the surface of the endless belt 11 after the fabric 61 is peeled off. Will do. For this reason, residual substances such as ink, bubbles, fluff, and lint attached to the surface of the endless belt 11 are physically scraped out, and these residuals are further collected by the suction device 50 disposed below the cleaning roller 48. The material is aspirated and removed with the cleaning solution. Therefore, according to this cleaning means 30, not only liquid substances such as residual ink and bubbles but also residual solid substances such as fluff, yarn waste, and dust, whose residuals cause problems in ink jet printing, can be removed.

<Another embodiment>
If the amount of ink passing through the recording medium 60 is extremely large and there is a large amount of ink on the endless belt 11, the rotation speed of the cleaning roller (1) 33 is prevented so that a large amount of bubbles are not generated in the first cleaning unit 31. Therefore, a large amount of ink that could not be removed remains on the endless belt 11.
When the cleaning roller (2) 34 is rotated at a high speed in order to completely remove the residual ink by the second cleaning unit 32, a large amount of bubbles may be generated in the second cleaning unit 32.
In this case, the rotational speed of the cleaning roller (2) 34 of the second cleaning unit 32 is also set to a rotational speed γ (rpm) at which bubbles are not generated from the back-through ink attached to the endless belt 11.

Therefore, a third cleaning unit (not shown) is installed for the purpose of removing ink that could not be removed by the second cleaning unit 32. The number of rotations δ (rpm) of the cleaning roller (3) (not shown) of the third cleaning unit is set so that the cleaning roller (2 of the second cleaning unit 32 can remove the ink remaining on the endless belt 11 with certainty. ) 34 is higher than the rotation speed γ (rpm).
Similarly, when bubbles are generated in the third cleaning unit, the number of rotations of the cleaning roller (3) of the third cleaning unit is set so as not to generate bubbles, and a fourth cleaning unit (not shown) is provided. In this way, it is possible to respond by providing a plurality of cleaning units according to the situation.

DESCRIPTION OF SYMBOLS 1 Inkjet recording device 10 Conveying means 11 Endless belt 12 Driven pulley 13 Driven pulley 14 Pressing roller 15 Pulley 20 Recording means 21 Inkjet head 30 Cleaning means 31 First cleaning part 32 Second cleaning part 33 Cleaning roller (1)
34 Cleaning roller (2)
35 Cleaning pipe 36 Wiping blade (1)
37 Wiping blade (2)
38 Washing tank (1)
39 Washing tank (2)
40 Washing water tank 41 Water supply roll 42 Drain port (1)
43 Drainage port (2)
44 Rotating shaft 45 Brush hair 46 Brush pitch 47 Channel width 48 Cleaning roller 50 Suction device 51 Suction pipe 52 Separator 53 Filter 54 Blower 55 Waste liquid port 60 Recording medium 61 Fabric

Claims (3)

An ink jet recording apparatus capable of ejecting ink and recording an image on a recording medium, comprising: a recording means on which a nozzle for ejecting the ink is formed; and an endless belt installed below the recording means, A feed path for rotating the endless belt in one direction and transporting the recording medium set on the transport surface formed on the outer peripheral surface of the endless belt from one end side to the other end side through the recording means A conveying means formed with a return path including a range in which the endless belt moves from the other end side to the one end side, and a first cleaning unit that cleans the outer peripheral surface of the endless belt in the return path; Cleaning means comprising a second cleaning unit disposed downstream of the first cleaning unit, wherein each cleaning unit has a cleaning roller, and the number of rotations of the cleaning roller can be individually adjusted. Do Ink jet recording apparatus.   The inkjet recording apparatus according to claim 1, wherein the first cleaning unit and / or the second cleaning unit includes a suction device. 3. The inkjet recording according to claim 1, wherein α <β, where α is the rotation number of the cleaning roller of the first cleaning unit and β is the rotation number of the cleaning roller of the second cleaning unit. apparatus.