JP7690834B2 - Liquid ejection device and embroidery system - Google Patents

Description

The present invention relates to a liquid ejection device and an embroidery system.

Conventionally, liquid ejection devices that eject liquid onto a linear medium such as a thread are known.

As a liquid ejection device, technology has been disclosed that uses a tension sensor to maintain a constant tension in the thread (see, for example, Patent Document 1).

Liquid ejection devices require stable image quality.

The aim of the present invention is to stabilize image quality.

A liquid ejection device according to one aspect of the present invention has a head that ejects liquid based on image data onto a linear medium being transported, and an adjustment means that is arranged downstream of the head in the transport direction of the linear medium and adjusts the transport speed of the linear medium, the adjustment means increasing the transport distance of the linear medium when the transport speed falls below a predetermined value , and the head stopping ejection of the liquid when the adjustment means cannot adjust the transport speed .

The present invention makes it possible to stabilize image quality.

1 is a diagram illustrating an example of an overall configuration of an embroidery system according to an embodiment; 2 is a diagram illustrating a functional configuration of a control unit in the embroidery system of FIG. 1 . 4A to 4C are diagrams illustrating an example of the operation of an adjustment unit in the embroidery system of FIG. 1 . 4 is a flow diagram illustrating a transport speed adjustment operation of the embroidery system of FIG. 1; 10A and 10B are diagrams illustrating the results of adjusting the conveying speed in the embroidery system of FIG. 1 .

Below, the embodiments of the invention will be described in detail with reference to the drawings. In each drawing, the same components are given the same reference numerals, and duplicate explanations will be omitted as appropriate.

The following describes an embodiment using an embroidery system that includes a liquid ejection device and an embroidery device as an example.

[Embodiment]
<Overall configuration example of embroidery system 1>
1 is a diagram illustrating an example of the overall configuration of an embroidery system 1. The embroidery system 1 includes a liquid ejection device 2 and an embroidery device 3. The liquid ejection device 2 is communicably connected to the embroidery device 3 via wire or wirelessly. The liquid ejection device 2 dyes the thread M by ejecting liquid onto the thread M. The embroidery device 3 performs embroidery using the thread M dyed by the liquid ejection device 2.

The thread M is an example of a linear medium. The thread M is a glass fiber thread, a wool thread, a cotton thread, a synthetic thread, a metal thread, a wool, cotton, polymer, or metal blend thread, a yarn, a filament, or a linear member (continuous substrate) to which a liquid can be applied. The thread M also includes braids, flat cords, etc.

The liquid ejection device 2 has a head 21 and an adjustment means 22. The liquid ejection device 2 ejects liquid from the head 21 onto the thread M, which is supplied from the thread spool 11 and transported along the transport direction 10, to dye the thread M.

The embroidery device 3 has a needle 31 connected to the thread M. The embroidery device 3 embroiders the fabric C with the needle 31 using the dyed thread M supplied from the liquid ejection device 2 through a through hole 33 provided in the housing 32, forming an embroidery pattern on the fabric C. The thread M is pulled out from the spool 11 and transported along the transport direction 10 as the thread M is embroidered on the fabric C by the embroidery device 3.

The head 21 ejects liquid onto the transported thread M based on image data that is the basis of the image to be formed on the thread M using the liquid.

The adjustment means 22 has a first nip roller 221, a second nip roller 222, a dancer roller 223, and a support roller 224. The adjustment means 22 is provided downstream of the head 21 in the conveying direction 10.

The first nip roller 221 and the second nip roller 222 each include a pair of rotatable rollers that sandwich and transport the yarn M between the pair of rollers. The dancer roller 223 is provided between the first nip roller 221 and the second nip roller 222, and is a roller that can move along the moving direction 20 indicated by the arrow while rotating. The support roller 224 is provided downstream of the second nip roller 222 in the transport direction 10, and is a roller that supports the yarn M.

The adjustment means 22 can adjust the conveying speed V of the yarn M by moving the dancer roller 223 along the moving direction 20 and changing the conveying distance of the yarn M conveyed by the adjustment means 22.

The liquid ejection device 2 also has a control means 23, a rotary encoder 24, a guide roller 25, a first sensor 26, and a second sensor 27.

The control means 23 controls the operation of the head 21 and the adjustment means 22. The rotary encoder 24 is provided upstream of the head 21 in the transport direction 10, and outputs a signal that detects the transport state of the yarn M to the control means 23. The transport state of the yarn M is, for example, the supply speed of the yarn M supplied from the spool 11, the state in which the yarn M is taut due to tension, etc. The control means 23 causes the head 21 to eject liquid in response to a signal from the rotary encoder 24 based on image data.

The guide roller 25 is composed of a pair of rollers arranged to sandwich the yarn M, and guides the yarn M dyed with the liquid toward the adjustment means 22.

The first sensor 26 is provided upstream of the adjustment means 22 in the conveying direction 10 and outputs a detection signal of the yarn M to the control means 23. The second sensor 27 is provided downstream of the adjustment means 22 in the conveying direction 10 and is an example of a detection means that outputs a detection signal of the yarn M to the control means 23.

The second sensor 27 includes, for example, a rotary encoder that is provided on a rotating body that contacts the yarn M and outputs a detection signal of the rotation angle that the rotating body rotates per unit time. The rotating body is a roller or the like that can rotate while supporting the yarn M by contacting the yarn M. However, the configuration of the second sensor 27 is not limited to this. For example, the second sensor 27 can also include a camera or the like that outputs a detection signal of an image formed on the yarn M by the liquid ejected from the head 21.

Based on the detection signal from the second sensor 27, the control means 23 calculates and obtains information on the conveying speed V of the yarn M downstream of the adjustment means 22 in the conveying direction 10, and outputs the information to the adjustment means 22. The adjustment means 22 can obtain information on the conveying speed V of the yarn M from the control means 23.

<Example of functional configuration of control means 23>
2 is a block diagram showing an example of a functional configuration of the control unit 23. The control unit 23 has an input/output unit 231, a determination unit 232, a conveying speed acquisition unit 233, an adjustment control unit 234, a discharge control unit 235, and a stop control unit 236.

The control means 23 may realize these functions by electrical circuits, or may realize some or all of these functions by software (CPU; Central Processing Unit). The control means 23 may realize these functions by multiple circuits or multiple pieces of software.

The input/output unit 231 controls the input/output of signals or data to the control means 23.

The determination unit 232 determines the lower limit value Lt of the conveying speed V of the yarn M based on image data Im input from an external device such as a PC (Personal Computer) via the input/output unit 231. The lower limit value Lt is an example of a predetermined value. For example, the determination unit 232 determines the lower limit value Lt based on a value obtained by converting the conveying speed V of the yarn M into a discharge frequency.

After careful consideration, the inventors found that ejection becomes unstable at around 10 Hz. Therefore, it is preferable to set the lower limit Lt to 10 Hz or higher.

The conveying speed acquisition unit 233 acquires information on the conveying speed V of the yarn M by calculation based on the detection signals from the first sensor 26 and the second sensor 27.

The adjustment control unit 234 adjusts the conveying speed V using the adjustment means 22 based on the information on the conveying speed V of the yarn M acquired by the conveying speed acquisition unit 233.

In particular, in this embodiment, when the conveying speed V of the yarn M falls below the lower limit value Lt, the adjustment control unit 234 adjusts the conveying speed V of the yarn M by increasing the conveying distance of the yarn M using the adjustment means 22.

For example, when the conveying speed Vd of the yarn M downstream of the adjustment means 22 in the conveying direction 10 falls below the lower limit value Lt, the adjustment control unit 234 increases the conveying distance of the yarn M using the adjustment means 22, thereby adjusting the conveying speed Vu of the yarn M upstream of the adjustment means 22 in the conveying direction 10 so that it does not fall below the lower limit value Lt. For example, when the conveying speed V of the yarn M converted into a discharge frequency falls below 10 Hz, the adjustment control unit 234 increases the conveying distance of the yarn M by moving the dancer roller 223 along the movement direction 20 using the adjustment means 22.

The ejection control unit 235 ejects liquid from the head 21 in response to a signal from the rotary encoder 24 based on the image data Im.

If the adjustment means 22 cannot adjust the conveying speed V of the yarn M, the stop control unit 236 causes the head 21 to stop ejecting liquid. For example, the stop control unit 236 can determine whether the adjustment means 22 can adjust the conveying speed V of the yarn M based on a detection signal from at least one of the first sensor 26 and the second sensor 27.

<Example of operation of embroidery system 1>
3 is a diagram illustrating an example of the operation of the adjustment means 22 in the embroidery system 1. When the conveying speed V of the thread M falls below a lower limit value Lt, under the control of the control means 23, the adjustment means 22 moves the dancer roller 223 in the direction indicated by the arrow of the movement direction 20 to increase the conveying distance of the thread M, thereby adjusting the conveying speed V of the thread M.

For example, when the conveying speed Vd of the yarn M downstream of the adjustment means 22 in the conveying direction 10 falls below the lower limit value Lt, the adjustment means 22 increases the conveying distance of the yarn M to adjust the conveying speed Vu of the yarn M upstream of the adjustment means 22 in the conveying direction 10 so that it does not fall below the lower limit value Lt. When the value of the conveying speed V of the yarn M converted to a discharge frequency by the determination unit 232 falls below 10 Hz, the adjustment means 22 increases the conveying distance of the yarn M.

Here, the head 21 may stop discharging liquid under the control of the control means 23 when the dancer roller 223 has moved through the movable range along the movement direction 20. When the head 21 stops discharging, the adjustment means 22 moves the dancer roller 223 in the direction opposite to the direction indicated by the arrow of the movement direction 20, thereby reducing the transport distance of the yarn M. After the dancer roller 223 is thus able to move along the movement direction 20, the head 21 resumes discharging liquid.

Figure 4 is a flowchart illustrating an example of the operation of adjusting the transport speed in the embroidery system 1. After an embroidery design is determined by a user of the embroidery system 1, the embroidery system 1 starts the operation of Figure 4 by inputting image data Im corresponding to the embroidery design.

First, in step S41, the embroidery system 1 determines the lower limit value Lt of the transport speed V of the thread M based on the image data Im using the determination unit 232. The determination unit 232 determines the transport speed V of the thread M by determining the liquid application amount (gradation) per unit length of the thread M based on the image data Im, and then converts the transport speed V into a discharge frequency to determine the lower limit value Lt.

Next, in step S42, the embroidery system 1 acquires information on the transport speed V of the thread M by calculation using the transport speed acquisition unit 233 based on the detection signals from the first sensor 26 and the second sensor 27.

Next, in step S43, the embroidery system 1 determines, via the adjustment control unit 234, whether the conveying speed V falls below the lower limit value Lt.

If it is determined in step S43 that the value is not less than the threshold (step S43, No), the embroidery system 1 ends its operation.

On the other hand, if it is determined in step S43 that the conveyance speed V falls below the predetermined value (step S43, Yes), the embroidery system 1 adjusts the conveyance speed V by increasing the conveyance distance of the thread M using the adjustment means 22 based on the information on the conveyance speed V of the thread M.

In this way, the embroidery system 1 can adjust the transport speed V of the thread M.

<Example of Adjustment Results of Conveying Speed V>
Fig. 5 is a diagram illustrating an example of the adjustment result of the conveying speed V by the embroidery system 1. The horizontal axis of Fig. 5 indicates time t, and the vertical axis indicates the conveying speed V. In Fig. 5, the solid line graph indicates the conveying speed Vd of the thread M downstream of the adjustment means 22 in the conveying direction 10. The dashed dotted line graph indicates the conveying speed Vu of the thread M upstream of the adjustment means 22 in the conveying direction 10.

As shown in FIG. 5, when the conveying speed Vd changes, the embroidery system 1 adjusts the conveying speed V of the thread M by the adjustment means 22 in accordance with the lower limit value Lt determined by the determination unit 232 so that the conveying speed Vu of the thread M upstream of the adjustment means 22 in the conveying direction 10 does not fall below the lower limit value Lt.

The hatched area 51 in FIG. 5 corresponds to the difference in the conveying speed V on the upstream and downstream sides of the adjustment means 22 in the conveying direction 10, and represents the adjustment of the conveying speed V by the adjustment means 22.

<Functions and Effects of Liquid Ejection Device 2>
The effects of the liquid ejection device 2 in the embroidery system 1 will be described.

Conventionally, in an embroidery system having a liquid ejection device and an embroidery device, the user must manually pull the thread just before starting embroidery to align the beginning of the embroidery pattern to be formed on the fabric with the tip of the needle to which the thread is connected. At this time, the thread transport speed may suddenly change.

In addition, if the stitching method changes significantly due to the embroidery design or if the stitching position jumps, the thread transport speed will change suddenly.

The liquid ejection device in the embroidery system ejects liquid while changing the ejection frequency in accordance with the thread transport speed to dye the thread M. Therefore, if the ejection frequency changes suddenly in accordance with the thread transport speed, the ejection may become unstable, or the image quality may deteriorate at color transitions or overlapping positions due to misalignment of the liquid applied to the thread.

In addition, if the tension of the thread transported in the embroidery system becomes too high, it will put a strain on the needle and the embroidery device itself. In embroidery systems that have a liquid ejection device, the tension of the thread may become high, so a configuration that can maintain a specified tension is required.

The liquid ejection device 2 according to this embodiment includes a head 21 that ejects liquid based on image data onto the transported thread M (linear medium), and an adjustment means 22 that is provided downstream of the head 21 in the transport direction 10 of the thread M and adjusts the transport speed V of the thread M. The adjustment means 22 increases the transport distance of the thread M when the transport speed V falls below a lower limit Lt (predetermined value). With this configuration, the liquid ejection device 2 can suppress abrupt changes in the transport speed of the thread M and suppress abrupt changes in the ejection frequency matched with the transport speed of the thread M, and as a result of stabilizing the ejection of liquid by the head 21, the image quality can be stabilized. In addition, the liquid ejection device 2 can maintain the tension of the transported thread M at a predetermined tension by adjusting the transport speed of the thread M, thereby reducing the burden on the needle and the embroidery device itself.

In addition, in this embodiment, when the conveying speed Vd downstream of the adjustment means 22 in the conveying direction 10 falls below the lower limit value Lt, the adjustment means 22 increases the conveying distance of the yarn M to adjust the conveying speed Vu upstream of the adjustment means 22 in the conveying direction 10 so that it does not fall below the lower limit value Lt. This allows the liquid ejection device 2 to suppress sudden changes in the conveying speed of the yarn M and to suppress sudden changes in the ejection frequency matched to the conveying speed of the yarn M, stabilizing the ejection of liquid by the head 21 and thereby stabilizing image quality.

Furthermore, as a result of careful consideration by the inventors, it was found that when the value obtained by converting the conveying speed V of the yarn M into a discharge frequency is close to 10 Hz, the discharge by the head 21 becomes unstable. Therefore, it is preferable to set the lower limit value Lt to 10 Hz or more. For example, it is preferable for the adjustment means 22 to increase the conveying distance when the value obtained by converting the conveying speed V into a discharge frequency falls below 10 Hz. This makes it possible to stabilize the discharge by the head 21 and stabilize the image quality by the liquid discharge device 2.

In addition, in this embodiment, the adjustment means 22 increases the conveying distance of the yarn M by moving the dancer roller 223, but when the dancer roller 223 moves to its limit, the conveying speed V cannot be adjusted. Therefore, when the adjustment means 22 cannot adjust the conveying speed V, it is preferable that the head 21 stops discharging liquid under the control of the stop control unit 236. This makes it possible to prevent a decrease in image quality due to an inability to adjust the conveying speed V. While the liquid discharge by the head 21 is stopped, the liquid discharge device 2 returns the position of the dancer roller 223 to make the conveying speed V adjustable again, and after the conveying speed V becomes adjustable, the head 21 can resume discharging liquid.

In addition, in this embodiment, the liquid ejection device 2 has a second sensor 27 (detection means) that is provided downstream of the adjustment means 22 in the conveying direction 10 and outputs a detection signal of the yarn M. The adjustment means 22 acquires information on the conveying speed V based on the detection signal from the second sensor 27. For example, the second sensor 27 includes a rotary encoder that is provided on a rotating body that contacts the yarn M and outputs a detection signal of the rotation angle that the rotating body rotates per unit time. The liquid ejection device 2 can accurately adjust the conveying speed V by adjusting the conveying speed V based on the acquired information on the conveying speed V.

Instead of a rotary encoder, the second sensor 27 may include a camera that outputs a detection signal of the image formed on the yarn M by the liquid ejected from the head 21.

[Other Preferred Embodiments]
Although the preferred embodiments have been described in detail above, the present invention is not limited to the above-described embodiments, and various modifications and substitutions can be made to the above-described embodiments without departing from the scope of the claims.

The "liquid" is not particularly limited as long as it has a viscosity and surface tension that allows it to be discharged from the head, but it is preferable that the viscosity is 30 mPa·s or less at room temperature and pressure, or when heated or cooled. More specifically, it is a solution, suspension, emulsion, etc. that contains a solvent such as water or an organic solvent, a colorant such as a dye or pigment, a functionalizing material such as a polymerizable compound, a resin, or a surfactant, a biocompatible material such as DNA, amino acids, proteins, or calcium, an edible material such as a natural dye, etc.

The energy sources for discharging liquid include piezoelectric actuators (laminated piezoelectric elements and thin-film piezoelectric elements), thermal actuators that use electrothermal conversion elements such as heating resistors, and electrostatic actuators that consist of a vibration plate and an opposing electrode.

In addition, in the terms used in the embodiments, image formation, recording, printing, imprinting, printing, modeling, etc. are all synonymous.

The ordinal numbers, quantities, and other numbers used in the description of the embodiments are all provided as examples to specifically explain the technology of the present invention, and the present invention is not limited to the exemplified numbers. In addition, the connections between the components are provided as examples to specifically explain the technology of the present invention, and do not limit the connections that realize the functions of the present invention.

Each function of the embodiments can be realized by one or more processing circuits. Here, the term "processing circuit" in this specification includes a processor programmed to execute each function by software, such as a processor implemented by an electronic circuit, and devices such as an ASIC (Application Specific Integrated Circuit), DSP (digital signal processor), FPGA (field programmable gate array), and conventional circuit modules designed to execute each function described above.

REFERENCE SIGNS LIST 1 embroidery system 11 thread winder 2 liquid ejection device 21 head 22 adjustment means 221 first nip roller 222 second nip roller 223 dancer roller 224 support roller 23 control means 231 input/output section 232 determination section 233 conveying speed acquisition section 234 adjustment control section 235 ejection control section 236 stop control section 24 rotary encoder 25 guide roller 26 first sensor 27 second sensor (an example of a detection means)
3 Embroidery device 10 Conveying direction 20 Moving direction 31 Needle 32 Housing 33 Through hole C Cloth Im Image data Lt Lower limit value (an example of a predetermined value)
M: Thread (an example of a linear medium)
V, Vd, Vu Transport speed

Japanese Patent Application Publication No. 7-000661

Claims (9)

a head that ejects liquid onto a linear medium being conveyed based on image data;
an adjustment unit that is provided downstream of the head in a transport direction of the linear medium and adjusts a transport speed of the linear medium,
the adjusting means increases a transport distance of the linear medium when the transport speed is lower than a predetermined value ;
The liquid ejection device , wherein the head stops ejecting the liquid when the conveying speed cannot be adjusted by the adjustment means . a head that ejects liquid onto a linear medium being conveyed based on image data;
an adjustment unit provided downstream of the head in a transport direction of the linear medium, the adjustment unit adjusting a transport speed of the linear medium;
a detection unit that is provided downstream of the adjustment unit in the transport direction and that outputs a detection signal for the linear medium,
The adjustment means acquires information about the transport speed based on the detection signal from the detection means, and increases a transport distance of the linear medium when the transport speed falls below a predetermined value. A liquid ejection device as described in claim 1 or 2, wherein the adjustment means adjusts the transport speed upstream of the adjustment means in the transport direction so that it does not fall below the predetermined value by increasing the transport distance of the linear medium when the transport speed downstream of the adjustment means in the transport direction falls below the predetermined value . The liquid ejection device according to claim 1 or 2, wherein the adjustment means increases the conveying distance when the conveying speed converted into an ejection frequency falls below 10 Hz. 3. The liquid ejection device according to claim 2, wherein the detection means is provided on a rotating body that is in contact with the linear medium, and outputs a detection signal indicating a rotation angle of the rotating body per unit time. 3. The liquid ejection apparatus according to claim 2, wherein the detection means outputs a detection signal of an image formed on the linear medium by the liquid ejected from the head. A liquid ejection device as described in claim 5 or 6, wherein the adjustment means adjusts the transport speed upstream of the adjustment means in the transport direction so that it does not fall below the predetermined value by increasing the transport distance of the linear medium when the transport speed downstream of the adjustment means in the transport direction falls below the predetermined value. 7. The liquid ejection device according to claim 5, wherein the adjustment means increases the transport distance when a value of the transport speed converted into an ejection frequency falls below 10 Hz. A liquid ejection device according to claim 1 ,
an embroidery device that performs embroidery using the linear medium to which the liquid has been applied by the liquid ejection device.

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