JP5317506B2 - Inkjet printing method and inkjet printing apparatus - Google Patents

Description

  The present invention relates to an inkjet printing method and an inkjet printing apparatus.

Conventionally, screen printing apparatuses, roller printing apparatuses, and the like have been widely used as apparatuses for printing on fabrics such as cotton, silk, and polyester. However, these printing apparatuses need to prepare a screen frame, an engraving roller, and the like for each pattern. However, the screen frame and the engraving roller are expensive, and thus are not suitable for printing a small variety of products. On the other hand, the ink jet textile printing apparatus is suitable for production of a small quantity and a wide variety of products since it can cope with the change of the design only by changing the digital data, and has been widely used in recent years. This ink jet textile printing apparatus can be roughly divided into a serial head system and a line head system. In one of these, a line head type ink jet printing apparatus has a plurality of head units each having a plurality of ejection openings arranged in the width direction of a printing object such as a cloth (a direction perpendicular to the traveling direction of the cloth). A line head is provided (for example, Patent Document 1). This line head type ink jet printing apparatus has the merit that the printing time can be shortened because the object to be printed can be continuously conveyed.
JP 2004-167847 A

  By the way, if the ink jet printing apparatus continues to discharge ink for a long time, the ink may be clogged in the discharge port of the head unit, something that obstructs discharge may adhere, or the discharge may not be deflected or discharged. It is necessary to interrupt and clean each head unit. In addition, the printing process may be temporarily interrupted for other reasons. However, once the printing process is stopped, when the printing process is restarted, the fabric transport speed at the time of start-up is slower than the normal transport speed. There is a problem in that the ink landing position shift and the discharge amount unevenness occur in the boundary portion with the printed region printed later, and the color unevenness occurs as compared with other portions.

  Accordingly, an object of the present invention is to provide an ink-jet printing method and an ink-jet printing apparatus capable of uniformly printing the boundary portion even when printing is interrupted halfway and printing is started again. To do.

  An inkjet printing method according to the present invention is made to solve the above-described problem, and includes a printing unit having a line head in which a plurality of head units each having a plurality of discharge ports arranged in the width direction of a printing object. An ink-jet printing method for printing a material to be printed, comprising: a first transporting process for transporting a printed material in a traveling direction; and each head unit of a printing unit during the first transporting process, A first discharge step for discharging ink, a stop step for stopping the first transport step and the first discharge step, and after the stop step, the printed material is transported for a predetermined distance in a direction opposite to the traveling direction. After the retreating process, after the retreating process, a second transporting process for transporting the printed material again in the advancing direction, and stopping the first transporting process for the printed material from the predetermined distance in the second transporting process. The A second discharge step of discharging ink to the printed material again from each head unit of the printing portion when the printed material is conveyed by a distance obtained by subtracting the braking distance advanced by the inertia force. Yes.

  In the above-described ink jet printing method, after stopping the first conveying step and the first discharging step, the printed material is once retracted by a predetermined distance in the retreating step, and then the printed material is again returned in the second conveying step. Transport in the direction of travel. Then, from the predetermined distance retracted in the retreating process, when the first conveying process is stopped, the printed material is conveyed in the traveling direction by a distance obtained by subtracting the braking distance advanced by the inertial force, and then the second discharge. Ink is ejected onto the object to be printed in the process. Thus, instead of starting ink discharge immediately after the start-up after resumption, since the article to be printed is once transported and the ink is discharged after the transport speed is stabilized, printing is performed in the first ejection step. The boundary portion between the printed area and the printed area in the second discharge process can be printed uniformly. The “predetermined distance” to be moved backward may be a distance that allows the conveyance speed to be stabilized, and varies depending on the function and speed of the inkjet printing apparatus, but is usually a distance obtained by adding about 50 to 100 mm to the braking distance. If it is. In addition, the braking distance traveled by the article to be printed by the inertial force includes a case where the distance is 0 mm. In this case, in the second ejection step, the ink may be ejected when the printed material is conveyed by a predetermined distance conveyed in the retreating step.

  The ink-jet textile printing method can be variously modified. For example, the ink-jet printing method further includes a capping step for preventing drying of the discharge port of each head unit and a cleaning step of cleaning the discharge port of each head unit in the stop step. It is preferable. As a result, clogging of the head unit with ink can be prevented.

  An inkjet printing apparatus according to the present invention has been made to solve the above-described problems, and is an inkjet printing apparatus for printing a printed material, and a conveyor belt for placing and conveying the printed material; A printing unit having a line head installed above the transport belt and having a plurality of head units formed with a plurality of discharge ports arranged in the width direction of the object to be printed; and the transport belt is driven in the forward and backward directions. And a control unit that controls the drive unit to advance and retreat the conveying belt by a predetermined distance and sends a signal to eject the ink to the textile printing unit.

  According to this ink jet textile printing apparatus, the driving means can drive the conveying belt not only in the traveling direction but also in the backward direction, and the control unit signals that the ink is ejected to the textile printing section while the conveying belt is advanced and retracted by a predetermined distance. Is configured to be able to send. For this reason, when printing is started again after the printing is temporarily stopped, the object to be printed is once retracted by a predetermined distance, then conveyed in the traveling direction, and advanced by a distance obtained by subtracting the braking distance from the retracted distance. At that time, ink can be ejected from the textile printing unit. As a result, ink discharge is not started immediately at the time of start-up after restarting, but is printed in the first discharge process because the printing object is conveyed by a predetermined distance and ink is discharged after the conveyance speed is stabilized. It is possible to uniformly print the boundary portion between the printed area and the printed area in the second ejection step.

  ADVANTAGE OF THE INVENTION According to this invention, even if it is a case where printing is interrupted and printing is started again, the inkjet printing method and inkjet printing apparatus which can print the boundary part uniformly can be provided.

  Hereinafter, embodiments of an ink jet textile printing apparatus according to the present invention will be described with reference to the drawings. FIG. 1 is a schematic perspective view of an ink jet printing apparatus according to this embodiment, and FIG. 2 is a schematic bottom view of a printing section according to this embodiment. The left side of FIG. 1 is referred to as the upstream side, the right side is referred to as the downstream side, the direction toward the downstream side is referred to as the traveling direction, and the direction toward the upstream side in the opposite direction is referred to as the backward direction.

  As shown in FIG. 1, an inkjet printing apparatus 1 includes an unwinding roller 2 that unwinds a fabric (printed object) C, an endless transport belt 3 that transports the fabric C, and an upstream side that drives the transport belt 3. A driving roller 4 and a downstream driving roller 5 are provided. A printing unit 6 for printing the fabric C is installed between the upstream driving roller 4 and the downstream driving roller 5 and above the conveying belt 3. The printing unit 6 and the upstream driving roller 4 are connected to the printing unit 6 and the upstream driving roller 4. A control unit 7 is connected. In addition, a pasting roller 8 is provided above the upstream drive roller 4 to attach the fabric C onto the transport belt 3. Still further, a take-up roller 9 that winds the fabric C conveyed to the downstream drive roller 5 and a dryer for drying the fabric C that has been peeled off from the downstream drive roller 5 and taken up by the take-up roller 9. A heater plate 10 is installed.

  Hereinafter, each member which comprises the inkjet textile printing apparatus 1 mentioned above is demonstrated.

  The transport belt 3 can employ various materials such as metal, rubber, and plastic, and an adhesive surface is formed on the outer surface thereof. This pressure-sensitive adhesive surface can be formed, for example, by applying a pressure-sensitive pressure-sensitive adhesive to the surface of the conveyor belt 3. Thus, since the adhesive surface is formed on the surface of the conveyance belt 3, the cloth C is affixed on the conveyance belt 3 by pressing the fabric C onto the conveyance belt 3 with the sticking roller 8 described later. Can do.

  The upstream drive roller 4 and the downstream drive roller 5 rotate in the forward direction and the reverse direction by rotating clockwise and counterclockwise in FIG. 1 using a motor (not shown) as a drive source. The upstream drive roller 4 and the downstream drive roller 5 are rotating at the same timing and at the same speed.

  As shown in FIG. 2, the printing unit 6 employs a line head system, and includes a line head 61 in which a plurality of head units 601 are arranged in a staggered manner in the width direction of the fabric C. Each head unit 601 is formed with an ejection port (not shown) for ejecting ink.

  The control unit 7 is connected to the upstream drive roller 4, can detect the rotation amount of the drive roller 4, and can calculate the conveyance amount of the conveyance belt 3, that is, the movement distance of the fabric C from the rotation amount. The control unit 7 is also connected to the textile printing unit 6, and sends a signal to eject the ink to the textile printing unit 6 based on the movement distance of the fabric C calculated from the rotation amount of the upstream drive roller 4. Send.

  The affixing roller 8 is installed on the upstream side of the conveyor belt 3 and presses the fabric C against the conveyor belt 3 by its own weight. The affixing roller 8 is in contact with the conveyor belt 3, and is configured to rotate along with the traveling of the conveyor belt 3.

  Next, a printing method using the above-described inkjet printing apparatus 1 will be described with reference to the drawings.

  First, as shown in FIG. 1, the fabric C unwound from the unwinding roller 2 is passed between the conveyance belt 3 and the sticking roller 8. As a result, the fabric C is pressed onto the transport belt 3 by the weight of the sticking roller 8 and is pasted onto the transport belt 3. The pressing force by the sticking roller 8 can be adjusted by changing the weight of the sticking roller 8 or can be adjusted by supporting both ends of the sticking roller 8 with a piston (not shown).

  The fabric C stuck on the transport belt 3 as described above is transported in the traveling direction by driving the transport belt 3 by the upstream drive roller 4 and the downstream drive roller 5 (first transport process). ). Then, while the fabric C is being transported in the traveling direction by the transport belt 3, the fabric C is printed by discharging ink from each head unit 601 of the line head 61 of the printing unit 6 to the fabric C (first). Discharge process). Then, the fabric C printed in this way is conveyed to the downstream drive roller 5, peeled off from the conveyance belt 3, and taken up by the take-up roller 9. The fabric C is heated and dried by the drying heater plate 10 until it is peeled off from the downstream drive roller 5 and taken up by the take-up roller 9.

  If the printing of the fabric C is continued for a long time by the above method, the ink adheres to the discharge surface around the discharge port of each head unit 601 of the line head 61 in the printing unit 6. It is necessary to stop the ejection and clean the ejection surface of the head unit 601. In addition, the conveyance of the fabric C and the discharge of the ink may be stopped halfway for various reasons (stop process). The case where the printing of the fabric C is started again after the conveyance of the fabric C and the ejection of the ink are once stopped for cleaning or other reasons will be described with reference to FIG.

  First, when the ejection of the ink from the line head 6 is stopped and the conveyance of the fabric C by the conveyance belt 3 is stopped, the conveyance belt 3 and the fabric C conveyed to the conveyance belt 3 are moved in the traveling direction by the braking distance a by the inertia force (see FIG. 3 (right side of FIG. 3) (FIG. 3A). The braking distance a is calculated by the control unit 7 from the rotation amount of the upstream drive roller 4.

  Then, from the state where the ink discharge and the conveyance of the fabric C are stopped in this way (FIG. 3A), the upstream drive roller 4 and the downstream drive roller 5 are once rotated counterclockwise to change the fabric C. Retreat by a predetermined distance L in the retreat direction (FIG. 3B) (retreat process). The predetermined distance L is preferably a distance obtained by adding about 50 to 100 mm to the braking distance a, and is calculated by the control unit 7 that detects the amount of rotation of the upstream drive roller 4. Then, after retracting by a predetermined distance L, the upstream drive roller 4 and the downstream drive roller 5 are rotated clockwise to convey the fabric C in the traveling direction (second conveying step), and the predetermined distance L When the control unit 7 detects that the braking distance a has been subtracted from the braking distance a (La), the control unit 7 sends a signal to the printing unit 6 to eject ink from each head unit 601 of the printing unit 6. Thus, the printing of the fabric C is resumed (FIG. 3C) (second discharge step). The head unit 601 can be cleaned by a known cleaning method such as wiping the ejection surface of the head unit 601 with a wiper, for example.

  As described above, according to the present embodiment, after the first conveyance process and the first discharge process are stopped, the fabric C is once retracted by the predetermined distance L in the retraction process, and then the fabric is again used in the second conveyance process. Transport C in the direction of travel. Then, the ink is ejected onto the fabric C in the second ejection step after being conveyed in the traveling direction by a distance (L−a) obtained by subtracting the braking distance a from the predetermined distance L retracted in the backward step. As described above, since the ink discharge is not started immediately at the time of start-up after the resumption of printing, but the fabric C is transported by the distance (La) and the transport speed is stabilized, the ink is started to be ejected. The boundary portion between the region printed in the discharging step and the region printed in the second discharging step can be printed uniformly.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to these, A various change is possible unless it deviates from the meaning of this invention. For example, in the above-described embodiment, the control unit 7 calculates the transport distance of the fabric C from the rotation amount of the upstream drive roller 4 and sends a discharge start signal to the textile printing unit 6. For example, it is connected to the downstream drive roller 5, and the transport distance of the fabric C may be calculated from the rotation amount of the downstream drive roller 5.

  In the above embodiment, the upstream drive roller 4 and the downstream drive roller 5 are rotated by a drive source such as a motor. However, the present invention is not limited to this, and for example, only the downstream drive roller 5 is driven. It may be rotated by the source, or only the upstream drive roller 4 may be rotated by the drive source. When only the downstream drive roller 5 is rotated, the control unit 7 is preferably connected to the downstream drive roller 5. When only the upstream drive roller 4 is rotated, the control unit 7 is connected to the upstream drive roller 4. It is preferable to connect.

It is a schematic perspective view which shows embodiment of the inkjet textile printing apparatus which concerns on this invention. It is a bottom view which shows the detail of the textile printing part which concerns on this embodiment. It is explanatory drawing which shows embodiment of the inkjet textile printing method which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Inkjet printing apparatus 3 Conveyor belt 4 Upstream drive roller (drive means)
5 Downstream drive roller (drive means)
6 Printing section 7 Control section

Claims (3)

An inkjet printing method for printing a printed material by a printing unit having a line head in which a plurality of head units in which a plurality of discharge ports are formed are arranged in the width direction of the printed material,
A first transporting process for transporting the printed material in the traveling direction;
A first discharge step of discharging ink from each head unit of the printing unit to the object to be printed during the first conveying step;
A stopping step of stopping the first conveying step and the first discharging step;
After the stopping step, a retreating step of conveying the printed material for a predetermined distance in the direction opposite to the traveling direction;
After the retreating step, a second conveying step for conveying the printed material again in the traveling direction;
When the printed material is conveyed by the distance obtained by subtracting the braking distance that the printed material has advanced due to inertia when the first conveying step is stopped from the predetermined distance in the second conveying step, the printing is performed again. A second ejection step of ejecting ink from each head unit of the section to the object to be printed;
An ink-jet textile printing method.   The ink-jet textile printing method according to claim 1, further comprising a cleaning step of cleaning a discharge port of each head unit in the stopping step. An ink jet printing apparatus for printing an object to be printed,
A transport belt for placing and transporting the object to be printed;
A printing unit having a line head installed above the transport belt and having a plurality of head units in which a plurality of discharge ports are formed arranged in the width direction of the object to be printed;
Drive means for driving the conveyor belt in the forward and backward directions;
A control unit for controlling the driving unit to advance and retreat the conveying belt by a predetermined distance and to send a signal to eject the ink to the printing unit;
An inkjet printing apparatus comprising:

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