Digital textile printing system for knit fabric

Abstract

This digital textile printing system for knit fabric comprises: a transport device including a transport belt that receives knit fabric at a supply position and transports the received knit fabric along a transport path while supporting the received knit fabric on an upper surface; a Webster guide that receives the knit fabric from the outside, spreads the received knit fabric, and supplies the knit fabric to the transport belt; and a press roller that is disposed at the supply position and guides the knit fabric supplied from the Webster guide to the upper surface of the transport belt. The Webster guide includes: an unwinder unit that spreads the knit fabric received from the outside; a fabric supply unit that supplies the knit fabric spread by the unwinder unit to the transport belt; and a control unit that controls operation of the fabric supply unit. The Webster guide may supply the knit fabric to the supply position from a position higher than the press roller.

Description

Digital textile printing system for knit fabrics

[0001] The present invention relates to a digital textile printing system, and in particular to a digital textile printing system comprising a Webster guide capable of unfolding and transporting a knitted fabric.

[0002] Fabric refers to a material that serves as a raw material for clothing. It is used not only as a fabric for forming human clothing but also for interior decoration, medical, transportation, and industrial materials. In order to enhance the aesthetic appeal according to the intended use, various types of patterns, logos, characters, and other images are printed on the surface of the fabric.

[0003] A representative fabric printing technique is screen printing, an analog method. In this process, the design to be printed is separated into individual colors, and ink is applied to the prepared color plates. The ink then penetrates the plates and transfers to the surface of the fabric. While this method allows for consistent print quality control and is suitable for mass production, it inevitably incurs initial costs and requires setup time due to the production of individual color plates, making it difficult to efficiently meet the demand for small-batch printing. In particular, the wastewater generated during the plate-making process contains a large amount of pollutants. Furthermore, significant amounts of wastewater are produced during post-processing steps (washing, steaming) performed to improve dye adhesion and ensure colorfastness, necessitating separate purification facilities.

[0004] As an alternative to overcome the economic and environmental limitations of such analog printing techniques, Digital Textile Printers (DTP) using inkjet printing technology have been introduced and are being used for printing on fabrics in the clothing sector, starting with sportswear, and in the home textile sector, such as curtains and rugs.

[0005] In order for DTP to print an image on the surface of a fabric using inkjet printing technology, a series of fabric transport processes is required to evenly spread out the fabric, which is rolled up or stacked on a cart, and supply it to the printing device. This transport process needs to satisfy various requirements depending on the weave structure of the fabric, the thickness of the yarn, and the type of yarn material.

[0006] In the case of a woven fabric with a structure in which weft threads (horizontal threads) and warp threads (vertical threads) are interwoven, the allowable tensile strength is determined by the yarn material and the thickness of the threads (number of threads, denier number). When the fabric is transported by a conventional DTP roll-to-roll transport device, the tension applied to the fabric does not exceed the allowable tensile strength, and since the shrinkage rate of the woven fabric is typically managed within a maximum of 3%, there are no major difficulties in fabric transport and inkjet printing, and it can be easily implemented if one has general knowledge regarding roll-to-roll transport.

[0007] However, in the case of knit fabrics with a structure in which stitches are woven one by one using a single thread, the main characteristic is that they have excellent elasticity depending on the weaving structure. When knit fabrics are transported using conventional DTP roll-to-roll transport technology, the fabric is supplied to the printing device in an elongated state due to the tension applied to it, and an image is printed. When printing is finished and the tension applied to the fabric is released, the fabric returns to its original state, causing the image to shrink in the longitudinal direction (the direction of fabric transport). Additionally, if the tension applied during fabric transport is excessive, there is a possibility that permanent deformation may occur in some cases.

[0008] Furthermore, due to their structural characteristics, knit fabrics exhibit a curling phenomenon where the edges curl in a direction perpendicular to the direction of applied tension. If supplied to a printing device without countermeasures against this curling, there is a risk of printhead damage caused by head friction and poor print quality.

[0009] In this regard, Registered Patent Publication No. 10-2286068 discloses an invention regarding a water-based coating system for an oil-based ink printed fabric.

[0010] The aforementioned background technology is one that the inventor possessed or acquired in the process of deriving the content of the disclosure of the present application, and it cannot be considered as prior art disclosed to the general public prior to the filing of this application.

[0011] One objective according to embodiments of the present invention is to provide a digital textile printing system for knit fabrics that can spread out and transport knit fabrics for image printing on knit fabrics.

[0012] One objective according to the embodiments of the present invention is to provide a textile printing system for knitwear that minimizes deformation of the fabric by minimizing the load (tension) applied to the knitwear during the process of conveying the knitwear.

[0013] One objective according to embodiments of the present invention is to provide a digital textile printing system for knitwear that can transport the fabric while minimizing the load (tension) applied to the fabric by varying the movement speed of the fabric passing through a specific location during the process of transporting the knitwear fabric.

[0014] A digital textile printing system for knit fabric according to one embodiment may include: a conveying device comprising a conveying belt that receives a knit fabric at a supply position and conveys the received knit fabric along a conveying path while supporting it through an upper surface; a Webster guide that receives the knit fabric from the outside and spreads the received knit fabric to the conveying belt; and a press roller disposed at the supply position and guiding the knit fabric supplied from the Webster guide to the upper surface of the conveying belt.

[0015] The above Webster guide may include an unwinder unit that unfolds a knit fabric supplied from the outside; a fabric supply unit that supplies the knit fabric unfolded by the unwinder unit to the conveyor belt; and a control unit that controls the operation of the fabric supply unit.

[0016] The above Webster guide can feed the knit fabric to the feed position at a position higher than the press roller.

[0017] In one embodiment, the unwinder may include a pair of support rollers that each rotate freely around a rotation axis parallel to one another and support the lower side of the knit fabric; and a first spreading roller that rotates around a rotation axis parallel to the pair of support rollers, contacts the portion of the knit fabric supported by the pair of support rollers, and spreads the knit fabric.

[0018] In one embodiment, the first spreading roller may be positioned between the pair of support rollers and configured so that its surface contacts the knit fabric on the upper side of the knit fabric portion.

[0019] In one embodiment, the first spreading roller may have a screw-shaped pattern formed on its surface extending from the center toward both ends of the rotation axis of the first spreading roller.

[0020] In one embodiment, the digital textile printing system for the knit fabric may further include a second spreading roller that is positioned adjacent to the press roller, rotates around a rotation axis parallel to the first spreading roller, and spreads the portion of the knit fabric supplied to the supply position and delivers it to the press roller.

[0021] In one embodiment, the second spreading roller may be configured so that its surface contacts the knit fabric at the lower side of the portion of the knit fabric supplied to the supply position.

[0022] In one embodiment, the fabric supply unit may include a drive roller that rotates around a drive shaft and has a rubber member mounted on its surface; and a drive motor that rotates the drive roller.

[0023] The above driving roller may be configured to support the lower side of the knit fabric and to transport the knit fabric to the conveying device through a rotational movement.

[0024] In one embodiment, the drive roller can move in both directions along the drive shaft.

[0025] In one embodiment, the fabric supply unit may further include a moving unit that moves the drive roller along the drive axis; and a guide sensor that detects the position of the knit fabric relative to the drive roller on the drive axis.

[0026] The above control unit can control the operation of the moving unit based on the detection information of the guide sensor.

[0027] In one embodiment, the digital textile printing system for knit fabric may further include a fabric detection unit positioned between the press roller and the fabric feeder, which detects whether the knit fabric is located at a detection position lower than the conveyor belt.

[0028] In one embodiment, the control unit may be configured to stop the operation of the fabric supply unit when it is determined that the knit fabric is located at the detection position, and to resume the operation of the fabric supply unit when it is determined that the knit fabric is not located at the detection position.

[0029] In one embodiment, the fabric sensing unit may include an optical laser that irradiates light; and a light detector that receives the light irradiated by the optical laser.

[0030] The control unit can determine that it is located at a detection position on the knit fabric if light is not received by the light detection unit.

[0031] In one embodiment, the digital textile printing system for knit fabric further includes a support frame that supports the lower side of the Webster guide, and the fabric sensing unit may be installed on the support frame.

[0032] In one embodiment, an additional fabric sensing unit located above the fabric sensing unit may be further included.

[0033] In one embodiment, the control unit may be configured to stop the operation of the fabric supply unit when it is determined that the knit fabric is not located at the detection position of the additional fabric detection unit, and to resume the operation of the fabric supply unit when it is determined that the knit fabric is located at the detection position of the additional fabric detection unit.

[0034] In one embodiment, the lower part of the fabric detection unit may further include a limit sensor to perform the role of the fabric detection unit when the fabric detection unit is not operating normally.

[0035] In one embodiment, the press roller may be movable in the vertical direction and configured to supply the knit fabric by pressing it against the upper surface of the conveyor belt.

[0036] In one embodiment, the digital textile printing system for the knit fabric may further include a textile printing device for printing on the knit fabric at a printing position located on the upper part of the conveyor belt and on the conveyor path.

[0037] In one embodiment, the conveyor belt forms a closed loop and rotates along the conveying path, and an adhesive material to which the knit fabric is adhered may be applied to the surface of the conveyor belt.

[0038] A digital textile printing system for knit fabric according to embodiments of the present invention can convey a knit fabric while spreading out the edges of the knit fabric through a spreading roller that rotates freely and contacts the surface of the knit fabric.

[0039] A digital textile printing system for knit fabric according to the embodiments can minimize the tension applied to the knit fabric by supplying the knit fabric through a fabric feeder positioned higher than the conveying device.

[0040] A digital textile printing system for knit fabric according to the embodiments can synchronize the supply speed of the knit fabric through the fabric supply unit and the transfer speed of the knit fabric through the transfer device by detecting the stretching of the knit fabric through the fabric detection unit.

[0041] The effects of the digital textile printing system for knit fabrics according to the embodiments are not limited to those mentioned above, and other effects not mentioned will be clearly understood by a person skilled in the art from the description below.

[0042] FIG. 1 is a schematic diagram of a digital textile printing system for knit fabric according to one embodiment.

[0043] FIG. 2a is an exemplary perspective view of a fabric supply unit illustrating a first spreading roller according to one embodiment.

[0044] FIG. 2b is a partial perspective view of a digital textile printing system for knit fabrics illustrating a second spreading roller according to one embodiment.

[0045] FIGS. 3A and FIGS. 3B are drawings illustrating the axis alignment operation of a drive roller according to one embodiment.

[0046] FIG. 4 is an exemplary drawing for explaining a fabric sensing unit according to one embodiment.

[0047] FIG. 5 is a schematic diagram showing a case where a knit fabric is excessively stretched in a digital textile printing system according to one embodiment.

[0048] FIG. 6 is a schematic diagram showing the case where a knit fabric is excessively pulled in a digital textile printing system according to one embodiment.

[0049] FIG. 7a is an image of a knit fabric when the knit fabric is supplied using a fabric supply method according to the prior art.

[0050] FIG. 7b shows an image of a knit fabric when the knit fabric is supplied using a digital textile printing system according to the present invention.

[0051] The various embodiments described in this specification are illustrative for the purpose of clearly explaining the technical concept of the present invention and are not intended to limit it to specific embodiments. The technical concept of the present invention includes various modifications, equivalents, alternatives, and embodiments selectively combined from all or part of each embodiment described in this specification. Furthermore, the scope of the technical concept of the present invention is not limited to the various embodiments presented below or the specific descriptions thereof.

[0052] Terms used in this specification, including technical or scientific terms, may have the meaning generally understood by those skilled in the art to which the present invention pertains, unless otherwise defined.

[0053] Expressions used herein such as “comprising,” “may compose,” “possessing,” “possessing,” “having,” and “possessing” imply the existence of the subject feature (e.g., function, operation, or component, etc.) and do not exclude the existence of other additional features. That is, such expressions should be understood as open-ended terms implying the possibility of including a second embodiment.

[0054] Expressions such as "first," "second," or "first," "second" as used in this specification are used to distinguish one object from another when referring to a plurality of objects of the same kind, unless otherwise indicated by the context, and do not limit the order or importance of said objects.

[0055]

[0056] FIG. 1 is a schematic diagram of a digital textile printing system for knit fabric according to one embodiment. FIG. 2a is an exemplary perspective view of a fabric feed unit illustrating a first spreading roller according to one embodiment. FIG. 2b is a partial perspective view of a digital textile printing system for knit fabric illustrating a second spreading roller according to one embodiment.

[0057] Referring to FIGS. 1, 2a, and 2b, a digital textile printing system (1) according to one embodiment can be used in a process of printing an image on a fabric, particularly a knit fabric. For example, the digital textile printing system (1) can move a manufactured knit fabric (K) along a set path and print an image (e.g., a logo, a print) on the surface of the knit fabric (K) at a printing position located on the set path. During the process of moving the knit fabric (K), the digital textile printing system (1) can spread out the edges of the knit fabric (K) to enable efficient printing on the knit fabric (K). During the process of spreading out and moving the knit fabric (K), the digital textile printing system (1) can reduce or minimize the tension applied to the knit fabric (K) to reduce or prevent damage to the knit fabric (K).

[0058] In one embodiment, the fabric conveyed through the digital textile printing system (1) may be a knit fabric. Knit refers to a fabric made by weaving threads formed by twisting fibers into loops, and may mean a fabric made by a so-called knitting method. Since a knit fabric can stretch and deform when tension is applied, it is necessary to minimize the tension applied to the knit fabric (K) when moving the knit fabric.

[0059] In one embodiment, the digital textile printing system (1) can reduce the load applied to the knit fabric (K) while spreading and moving the knit fabric (K). In the present invention, the fabric used in the digital textile printing system (1) is described as being a knit fabric (K), but it should be noted that the fabric used in the digital textile printing system (1) is not necessarily limited to a knit material fabric, and various types of fabrics susceptible to tension can be used in the digital textile printing system (1).

[0060] Additionally, in the illustrated embodiment, the knit fabric (K) is illustrated as being transported through the digital textile printing system (1). It should be noted that the knit fabric (K) fed into the digital textile printing system (1) may be fed in an initially crumpled state, but is not necessarily limited thereto.

[0061] In one embodiment, a digital textile printing system (1) for knit fabric may include a support frame (150), a Webster guide including a first spreading roller (122), a plurality of guide rollers (171), a conveying device (100), a press roller (162), a second spreading roller (161), a fabric detection unit (180), a control unit (not shown), and a textile printing device (110).

[0062] In one embodiment, as illustrated, the knit fabric (K) can be fed into the Webster guide and then supplied to the transfer device (100) in a spread-out state by the Webster guide. The knit fabric (K) fed into the digital textile printing system (1) can be moved in one direction by the movement of the Webster guide and the transfer device (100) and can be printed sequentially at the printing position.

[0063] In one embodiment, the Webster guide may be positioned on the upper part of the support frame (150). The Webster guide may be positioned by the support frame (150) at a higher position than the conveyor belt (101) of the conveyor device (100) described later. In one embodiment, the Webster guide may receive a knitted fabric (K) from the outside, and may spread out the received knitted fabric (K) and supply it to the conveyor device (100).

[0064] The Webster guide may include an unwinder unit (120) that unfolds the supplied knit fabric (K), and a fabric supply unit (130) that applies an external force to the knit fabric (K) unfolded by the unwinder unit (120) and supplies it to a conveying device (100).

[0065] In one embodiment, the unwinder part (120) may include a pair of support rollers (121a, 121b) that support the lower side of the knit fabric (K), and a first spreading roller (122) that contacts the surface of the knit fabric (K) supported by the pair of support rollers (121a, 121b).

[0066] In one embodiment, a pair of support rollers (121a, 121b) may be arranged parallel to each other. A pair of support rollers (121a, 121b) may each be configured to rotate freely around a rotation axis parallel to each other. A pair of support rollers (121a, 121b) may have substantially the same diameter, but are not limited thereto. The rotation axes of a pair of support rollers (121a, 121b) may be arranged at substantially the same height relative to the ground.

[0067] A knit fabric (K) introduced from the outside is partially stretched over a pair of support rollers (121a, 121b) and can be partially spread out parallel to the ground by the pair of support rollers (121a, 121b). In one embodiment, since the pair of support rollers (121a, 121b) are not connected to a separate power source and can rotate freely, they can rotate in one direction (e.g., counterclockwise in FIG. 1) in accordance with the movement of the knit fabric (K) stretched over the top.

[0068] In one embodiment, the first spreading roller (122) may be positioned between a pair of support rollers (121a, 121b). The first spreading roller (122) may rotate around a rotation axis parallel to the pair of support rollers (121a, 121b) (e.g., an axis parallel to the Y-axis). The rotation axis of the first spreading roller (122) may be located at a position higher than the rotation axis of the pair of support rollers (121a, 121b) relative to the ground.

[0069] In one embodiment, the first spreading roller (122) may come into contact with a portion of the knit fabric (K) supported by a pair of support rollers (121a, 121b), for example, the upper surface of the knit fabric (K) spanning over the upper side of the pair of support rollers (121a, 121b). The first spreading roller (122) may rotate around a rotation axis (e.g., clockwise in FIG. 1) in accordance with the conveyance of the knit fabric (K).

[0070] In one embodiment, the first spreading roller (122) rotates while in contact with the upper surface of the knit fabric (K) and can function to spread the contacted portion of the knit fabric (K) toward both edges (e.g., the Y-axis direction of FIG. 1).

[0071] In one embodiment, the first spreading roller (122) may have a pattern formed on its surface to spread the contacted knit fabric (K) in the width direction. For example, as shown in FIG. 2a, the first spreading roller (122) may have a screw-shaped pattern formed on its surface extending from the axial center toward both ends of the rotation axis. However, it should be noted that the above-described pattern is merely an example for convenience of explanation, and the surface shape of the first spreading roller (122), or the pattern formed on its surface, may be formed in various known shapes capable of spreading the contacted fabric. In one embodiment, the knit fabric (K) passes through the unwinder section (120), spreads in the width direction, and can be supplied to the fabric supply section (130).

[0072] In one embodiment, the fabric supply unit (130) can transfer the knit fabric (K) that has been unfolded and passed through the unwinder unit (120) to the transfer device (100). The fabric supply unit (130) is controlled by a control unit, thereby selectively implementing the transfer operation of the knit fabric (K) to the transfer device (100).

[0073] In one embodiment, the fabric supply unit (130) may include a drive roller (131) that rotates around a drive shaft (A), a drive motor (133) that drives the drive roller (131), a moving unit that translates the drive roller (131) along the drive shaft (A), and a guide sensor (140) that detects the position of the knit fabric (K) wound on the drive roller (131).

[0074] In one embodiment, the drive roller (131) can rotate in both directions around the drive axis (A). The drive axis (A) of the drive roller (131) can be parallel to the axis of rotation of a pair of support rollers (121a, 121b) (e.g., parallel to the Y-axis of FIG. 1).

[0075] In one embodiment, a drive motor (133) may be connected to the drive shaft (A) of the drive roller (131). The drive roller (131) may rotate in both directions around the drive shaft (A) by the drive motor (133).

[0076] In one embodiment, a rubber member (132) having a predetermined frictional force may be mounted on the surface of the drive roller (131), for example, the outer surface.

[0077] In one embodiment, the drive roller (131) can support the lower side of the knit fabric (K) that has passed through the unwinder section (120). In other words, the knit fabric (K) can be partially stretched over the upper side of the surface of the drive roller (131). In one embodiment, the drive roller (131) is rotated by a drive motor (133) and can apply an external force to the knit fabric (K) stretched over the upper side. When the drive roller (131) rotates (e.g., counterclockwise in FIG. 1), the knit fabric (K) can be transported toward the conveying device (100) by the frictional force of the rubber member (132). The drive roller (131) applies an external force to the knit fabric (K) that is stretched across the upper surface by the frictional force of the rubber member (132), and since the knit fabric (K) moves downward from the drive roller (131) by gravity, the external force applied to the knit fabric (K) can be minimized or reduced compared to the case where the knit fabric (K) is wound around the drive roller (131) and moves.

[0078] In one embodiment, the drive roller (131) can partially translate along the drive axis (A) (e.g., in the Y-axis direction). The drive axis (A) of the drive roller (131) can be connected to a moving part, and the linear position of the drive roller (131) in the direction of the drive axis (A) can be partially adjusted by the operation of the moving part.

[0079] In one embodiment, the guide sensor (140) can detect the position of the knit fabric (K) across the drive roller (131) along the drive axis (A). The guide sensor (140) can detect whether the knit fabric (K) across the drive roller (131) is eccentric along the direction of the drive axis (A). Based on the information detected by the guide sensor (140), the moving part can align the position of the drive roller (131) along the direction of the drive axis (A). A detailed explanation thereof will be provided later.

[0080] In one embodiment, the knit fabric (K) that has passed through the fabric supply unit (130) may be supplied to the conveying device (100). In one embodiment, a plurality of guide rollers (171) that partially contact the surface of the knit fabric (K) may be arranged between the fabric supply unit (130) and the conveying device (100). The plurality of guide rollers (171) guide the movement of the knit fabric (K) moving between the fabric supply unit (130) and the conveying device (100) and may rotate freely around their respective rotation axes. Although an embodiment in which three guide rollers (171) are arranged is shown in FIG. 1, it should be noted that this is an example for convenience of explanation, and various arrangements and numbers of guide rollers (171) may be provided in the digital textile printing system (1).

[0081] In one embodiment, the conveying device (100) can receive a knit fabric (K) in an unfolded state and convey it along a set path. In one embodiment, the conveying device (100) can receive a knit fabric (K) at a supply location and convey the received knit fabric (K) along a conveying path. In one embodiment, the conveying device (100) may include a conveying belt (101) that moves while supporting the received knit fabric (K) through its upper surface. For example, the conveying belt (101) may be provided in the form of a conveyor belt that rotates in a closed loop by being wound around a conveyor roller (102) as shown in FIG. 2b, but the form of the conveying belt (101) is not limited thereto.

[0082] The conveyor belt (101) supports the knit fabric (K) supplied through its upper surface (e.g., a surface facing the +Z direction) and can transport the supported knit fabric (K) along a transport path. The conveyor belt (101) is configured to receive the knit fabric (K) at a supply location where a press roller (162), described later, is positioned, transport the supplied knit fabric (K) along the transport path, and then discharge it to the outside at a discharge location located at the end of the transport path.

[0083] In one embodiment, a printing position where a textile printing device (110), described later, performs printing may be located on the conveying path where the conveying belt (101) conveys the knit fabric (K), but is not necessarily limited thereto. For example, the textile printing device (110) may not be placed on the conveying path of the conveying belt (101).

[0084] In one embodiment, the conveyor belt (101) may be formed to have a certain frictional force so that the knit fabric (K) supported on its upper surface does not slip during the process of conveying the knit fabric (K). For example, the surface of the conveyor belt (101) may be formed of a material having frictional force, such as rubber. In another example, an adhesive material having a certain adhesive force may be applied to the surface of the conveyor belt (101) so that the knit fabric (K) placed thereon can be stably adhered. Known adhesive materials may be used as adhesive materials in the present invention, and for example, an acrylic adhesive is preferred.

[0085] In one embodiment, a press roller (162) is installed at a supply position and can guide the supply of knit fabric (K) to a conveyor belt (101). In one embodiment, the press roller (162) may be positioned on the upper side of the conveyor belt (101). The knit fabric (K) can be supplied to a conveyor device (100) through the space between the press roller (162) and the upper surface of the conveyor belt (101).

[0086] In one embodiment, the press roller (162) may rotate around a rotation axis (e.g., a rotation axis parallel to the Y-axis direction of FIG. 1). The press roller (162) may come into contact with the upper surface of the knit fabric (K) located at the supply position. In one embodiment, the press roller (162) may move partially along an up-and-down direction perpendicular to the ground.

[0087] According to this structure, the press roller (162) can press the knit fabric (K) toward the upper surface of the conveyor belt (101), for example, toward the lower side. By pressing the portion of the knit fabric (K) in contact with the lower side against the upper surface of the conveyor belt (101), the press roller (162) can settle the portion of the knit fabric (K) supplied to the supply position onto the upper surface of the conveyor belt (101).

[0088] The press roller (162) can rotate freely around a rotation axis. Accordingly, when the knit fabric (K) is conveyed according to the rotational movement of the fabric supply unit (130) and the conveyor belt (101), the press roller (162) rotates in accordance with the movement of the contacted knit fabric (K) (e.g., clockwise in FIG. 1) and can guide the conveyance of the knit fabric (K).

[0089] In one embodiment, the second spreading roller (161) is positioned adjacent to the supply position and can spread out the knit fabric (K) and supply it between the press roller (162) and the conveyor belt (101). In one embodiment, the second spreading roller (161) can rotate freely around a rotation axis parallel to the first spreading roller (122).

[0090] In one embodiment, the second spreading roller (161) can support the lower side of the portion of the knit fabric (K) supplied to the supply position. For example, the knit fabric (K) can be partially stretched over the upper side of the surface of the second spreading roller (161).

[0091] In one embodiment, the second spreading roller (161) may have a pattern formed on its surface to spread the contacted knit fabric (K) in the width direction. For example, the first spreading roller (122) may have a screw-shaped pattern formed on its surface extending from the axial center toward both ends of the rotation axis, as shown in FIG. 2b. However, it should be noted that the above-described pattern is merely an example for convenience of explanation, and the surface shape of the second spreading roller (161), or the pattern formed on its surface, may be formed in various known shapes capable of spreading the contacted fabric. In one embodiment, the knit fabric (K) spread by the second spreading roller (161) may be supplied between the press roller (162) and the conveyor belt (101).

[0092] In one embodiment, the second spreading roller (161) can be in contact with the lower surface of the knit fabric (K) to spread the knit fabric (K) in the width direction. In one embodiment, since the first spreading roller (122) is in contact with the upper surface of the knit fabric (K) and the second spreading roller (161) is in contact with the lower surface of the knit fabric (K), the digital textile printing system (1) can spread both surfaces of the knit fabric (K) conveyed through the first spreading roller (122) and the second spreading roller (161) toward the width direction edges and convey them.

[0093] In one embodiment, a fabric detection unit (180) is positioned between a press roller (162) and a fabric supply unit (130) and can detect whether the knit fabric (K) supplied from the fabric supply unit (130) is located at a position lower than the conveyor belt (101). For example, the fabric detection unit (180) can detect that the knit fabric (K) is excessively supplied by the fabric supply unit (130), causing the knit fabric (K) to sag downwards. Based on the information detected by the fabric detection unit (180), a control unit can control the operation of the fabric supply unit (130). This will be described later.

[0094] In one embodiment, the textile printing device (110) can print on the surface of a unfolded knit fabric (K). In one embodiment, the textile printing device (110) can perform printing on the surface of a fabric being transported along a transport path through a transport device (100). For example, the textile printing device (110) may be positioned above the transport device (100), such as above a transport belt (101), and may perform printing on the knit fabric (K) through a print head (111) at a printing position located on the transport path. The textile printing device (110) may be provided in various forms of devices capable of performing printing on the fabric. In the drawing, an embodiment is shown in which a textile printing device (110) is provided on the upper part of a conveying device (100), but alternatively, the textile printing device (110) may be positioned at the rear end of the conveying device (100) to perform printing on the surface of a knit fabric (K) discharged from the conveying device (100), and in other examples, it may be omitted from the digital textile printing system (1).

[0095] In one embodiment, the control unit can control the operation of the fabric supply unit (130).

[0096] FIGS. 3A and FIGS. 3B are drawings illustrating the axis alignment operation of a drive roller according to one embodiment.

[0097] With reference to FIGS. 3a and 3b, the axis alignment operation of the drive roller (131) through the control unit will be described. In one embodiment, the drive roller (131) is in contact with the knit fabric (K) to partially support the lower side of the knit fabric (K), and can transport the knit fabric (K) toward the conveying device (100) through frictional force due to rotation. Since the knit fabric (K) moves while being stretched across a part of the surface of the drive roller (131), the position of the knit fabric (K) stretched across the drive roller (131) can be partially eccentric along the direction of the drive axis (A) of the drive roller (131).

[0098] In one embodiment, the drive roller (131) may partially translate along the drive axis (A). For example, the drive roller (131) may partially move along the drive axis (A) by the operation of the moving part. As the drive roller (131) partially moves along the drive axis (A), the position of the knit fabric (K) across the drive roller (131) may be aligned with respect to the drive roller (131). For example, alignment of the knit fabric (K) with respect to the drive roller (131) may mean that the width-direction center of the knit fabric (K) coincides with the drive axis (A)-direction center of the drive roller (131).

[0099] In one embodiment, the guide sensor (140) can detect the alignment state of the knit fabric (K) with respect to the drive roller (131). For example, the guide sensor (140) may be positioned below the drive roller (131). In one embodiment, the guide sensor (140) is provided in plurality, and the plurality of guide sensors (140) may be arranged side by side at regular intervals along the width direction of the knit fabric (K). For example, the guide sensors (140) may be arranged at intervals of 1 to 50 mm, a spacing of 5 to 30 mm is more preferable, and a spacing of 7 to 15 mm is possible.

[0100] In one embodiment, a plurality of guide sensors (140) can detect whether the knit fabric (K) is eccentric in the width direction. For example, the guide sensors (140) may be provided in the form of light sensors that irradiate light toward the surface of the knit fabric (K). For instance, as shown in FIG. 3a, if the knit fabric (K) is eccentric in one direction (e.g., to the left) relative to the drive roller (131), the light irradiated by some of the guide sensors (140) located on the right among the plurality of guide sensors (140) may not be irradiated toward the surface of the knit fabric (K). Based on the information detected by the plurality of guide sensors (140), the control unit can detect the alignment state of the knit fabric (K) relative to the drive roller (131), for example, the eccentric state of the knit fabric (K) relative to the drive roller (131). If the control unit determines that the knit fabric (K) is eccentric in one direction with respect to the drive axis (A) of the drive roller (131), it can move the drive roller (131) in the direction of the drive axis (A) so that the center of the drive roller (131) in the direction of the drive axis (A) is aligned with the center of the knit fabric (K) in the width direction. For example, the control unit can move the drive roller (131) in the direction of the drive axis (A) through the operation of the moving unit. For example, if it is detected that the knit fabric (K) is eccentric to the left of the drive roller (131) as in FIG. 3a, the control unit can align the drive roller (131) to the center of the knit fabric (K) in the width direction by moving the drive roller (131) to the right along the direction of the drive axis (A) as in FIG. 3b. According to this operation, the phenomenon in which the knit fabric (K) across the drive roller (131) is skewed in one direction and the edge in the width direction is wrinkled can be reduced or prevented.

[0101] FIG. 4 is an exemplary drawing for explaining a fabric sensing unit according to one embodiment. FIG. 5 is a schematic diagram of a digital textile printing system (1) for knit fabric for explaining the operation of a fabric sensing unit according to one embodiment.

[0102] Referring to FIGS. 4 and 5, the control unit can synchronize the supply speed of the knit fabric (K) through the fabric supply unit (130) via the fabric detection unit (180) with the transfer speed of the knit fabric (K) through the transfer device (100).

[0103] In one embodiment, the Webster guide, i.e., the fabric supply unit (130), can supply the knit fabric (K) at a position higher than the press roller (162) positioned at the supply position of the conveying device (100). The portion of the knit fabric (K) discharged from the fabric supply unit (130) can be supplied to the lower side of the fabric supply unit (130) and then supplied to the supply position of the conveying device (100) through the second spreading roller (161) and the press roller (162).

[0104] According to this structure, the fabric discharged from the fabric supply unit (130) is naturally stretched by gravity and supplied to the conveying device (100), so the tension acting on the knit fabric (K) can be minimized or reduced. At this time, it is important to appropriately adjust the speed at which the knit fabric (K) is discharged from the fabric supply unit (130) and the speed at which the knit fabric (K) is conveyed through the conveying device (100) so that the tension acting on the knit fabric (K) is minimized. For example, if the speed at which the knit fabric (K) is discharged (feeded) from the fabric supply unit (130) is excessively faster than the speed at which the knit fabric (K) is conveyed through the conveying device (100), as shown in FIG. 5, a phenomenon may occur where the portion of the knit fabric (K) located between the fabric supply unit (130) and the conveying device (100) stretches downward toward the conveying device (100). If the knit fabric (K) stretches excessively in this way, a load is generated due to its own weight, so excessive tension may be applied. If an excessive load is applied to the knit fabric (K), left-right curling occurs. Additionally, if the load is inconsistent, the degree of stretching changes, resulting in an uneven image after printing. Therefore, it is important to minimize the load (tension) applied to the knit fabric (K) while maintaining it consistently.

[0105] Conversely, it is also undesirable for the knit fabric (K) located between the fabric supply unit (130) and the conveying device (100) to be kept excessively taut, as this puts a load on the fabric. As shown in FIG. 6, if the knit fabric (K) between the fabric supply unit (130) and the conveying device (100) is kept taut without any stretching, excessive tension is applied in the same way as when it is excessively stretched, and problems as described above may occur.

[0106] Accordingly, as illustrated in FIG. 1, the load can be minimized by maintaining the knit fabric (K) to a degree that naturally stretches between the fabric supply unit (130) and the conveying device (100).

[0107] In one embodiment, the fabric detection unit (180) is positioned between the fabric supply unit (130) and the conveying device (100), and can detect whether the degree to which the knit fabric (K) discharged from the fabric supply unit (130) is stretched downwards toward the conveying device (100) is maintained at a constant level. For example, the fabric detection unit (180) may be positioned between the press roller (162) positioned at the supply position of the conveying device (100) and the fabric supply unit (130). The fabric detection unit (180) can detect whether the knit fabric (K) is located at a detection position lower than the conveying belt (101) and provide the detected information to the control unit.

[0108] In one embodiment, the fabric sensing unit (180) may be placed on a support frame (150) that supports the fabric supply unit (130), as shown in FIG. 4. However, this is merely an example, and the location of the fabric sensing unit (180) is not limited thereto.

[0109] The fabric detection unit (180) may include an optical laser (181) that emits light at a detection location and a light detection unit (182) that receives the light emitted by the optical laser (181). In one embodiment, the detection location may be located 1 to 20 cm below the lowest guide roller (171), preferably 2 to 10 cm below, and most preferably 3 to 7 cm below. By configuring it in this way, the knit fabric (K) can be prevented from stretching excessively and a minimum load can be applied consistently. For example, a state in which the knit fabric (K) is located at a height below the detection location can be understood as a state in which the knit fabric (K) is excessively stretched because the fabric transport speed of the fabric supply unit (130) and the transport device (100) is not synchronized at an appropriate speed.

[0110] In one embodiment, as shown in FIG. 5, when the knit fabric (K) is stretched to a height below the detection position, the light irradiated from the optical laser (181) may be blocked by the knit fabric (K) located at the detection position and may not be irradiated to the light detection unit (182). On the other hand, as shown in FIG. 1, when the knit fabric (K) is supplied from the fabric supply unit (130) to the transfer device (100) at a normal speed, the knit fabric (K) is positioned at a higher position than the detection position, so the light detection unit (182) can receive the light irradiated from the optical laser (181).

[0111] In one embodiment, when light from the optical laser (181) is not received by the light detector (182), the control unit may determine that the knit fabric (K) is in a state where it is located at the detection position, for example, that the knit fabric (K) is excessively stretched downwards on the conveyor belt (101). On the other hand, when light from the optical laser (181) is received by the light detector (182), the control unit may determine that the knit fabric (K) is being conveyed in a normal state as shown in FIG. 1.

[0112] In one embodiment, when the control unit determines that the knit fabric (K) is located at the detection position, it may stop the operation of the fabric supply unit (130), for example, stop the rotation of the drive roller (131). In this case, when the knit fabric (K) is transported by the conveyor belt (101), the knit fabric (K) is removed from the normal state position, i.e., the detection position, and the light of the optical laser (181) can be received again by the light detection unit (182). When the control unit determines that the knit fabric (K) is not located at the detection position, it may rotate the drive roller (131) to resume the operation of the fabric supply unit (130).

[0113] In another example, the control unit may be configured to reduce the rotational speed of the drive roller (131) to reduce the speed at which the knit fabric (K) is discharged from the fabric supply unit (130) when it is determined that the knit fabric (K) is located at the detection position based on the detection information of the fabric detection unit (180), or to reverse the rotation of the drive roller (131) (e.g., clockwise rotation in FIG. 5) to position the knit fabric (K) in a normal state. For example, the digital textile printing system (1) may be configured to supply the knit fabric (K) to the upper part of the conveying belt (101) in a sufficiently unfolded state by spreading the knit fabric (K) with a certain level of tension applied based on the detection information of the fabric detection unit (180) and supplying it to the conveying device (100).

[0114] In one embodiment, the fabric detection unit (180) may be composed of two or more. For example, an additional fabric detection unit (not shown) may be configured to detect a position where the knit fabric (K) is excessively pulled as shown in FIG. 6. In such an embodiment, the detection position may be a position corresponding to the lowest guide roller (171) or located at a certain distance below the lowest guide roller (171), but above the detection position for detecting the state where the knit fabric (K) is excessively stretched. For example, the detection position may be located 0.1 to 10 cm below the lowest guide roller (171), preferably 0.1 to 5 cm below, and most preferably 0.5 to 3 cm below. The additional fabric detection unit may determine that the knit fabric (K) is excessively pulled if the knit fabric (K) is not located at the detection position, and determine that the knit fabric (K) is maintained in a naturally stretched state so that a minimum load is applied if it is located at the detection position.

[0115] In one embodiment, the control unit is configured to stop the operation of the fabric supply unit when it is determined that the knit fabric (K) is not located at the detection position of the additional fabric detection unit, and to resume the operation of the fabric supply unit when it is determined that the knit fabric (K) is located at the detection position of the additional fabric detection unit, thereby allowing the position of the lowest part of the knit fabric (K) to be maintained at a constant level.

[0116] In another example, if the control unit determines that the knit fabric (K) is not located at the detection position of an additional fabric detection unit, it may be configured to reduce the rotational speed of the drive roller (131) to reduce the speed at which the knit fabric (K) is discharged from the fabric supply unit (130), or to reverse the drive roller (131) (e.g., clockwise rotation in FIG. 6) to position the knit fabric (K) in a normal state.

[0117] In this way, by arranging two fabric sensing units at regular intervals, the bottom part of the knit fabric (K) can be maintained at a constant position, and thereby a constant load can be maintained on the knit fabric (K).

[0118] In one embodiment, the printing system of the present invention may additionally be provided with one or more limit sensors (not shown). The limit sensors may be provided at the lower end of the fabric detection unit in case the fabric detection unit does not operate normally.

[0119] The above one or more limit sensors are provided at the bottom of each fabric detection unit and can perform the role of the fabric detection unit when the fabric detection unit does not operate normally due to reasons such as a malfunction, and with this configuration, it is possible to ensure that no excessive load is applied to the knit fabric under any circumstances.

[0120] FIG. 7a is an image of a knit fabric when supplied using a fabric supply method according to the prior art, and FIG. 7b is an image of a knit fabric when supplied using the digital textile printing system of the present invention. In FIG. 7a, a portion of the edge measuring approximately 3 to 5 cm is rolled inward, making it impossible to print smoothly and thus preventing the provision of high-quality printed material. On the other hand, in FIG. 7b, the fabric is spread out to the outermost side of the knit fabric, allowing for the utilization of a large area of ​​the fabric and enabling high-quality printing.

[0121]

[0122] As explained above, a person skilled in the art to which the present invention pertains will understand that the present invention may be implemented in other specific forms without altering its technical concept or essential features. Therefore, the embodiments described above should be understood as illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims set forth below rather than by the detailed description, and all modifications or variations derived from the meaning and scope of the claims and equivalent concepts should be interpreted as being included within the scope of the present invention.

[0123] The features and advantages described herein are not all included, and in particular, many additional features and advantages will become apparent to those skilled in the art by considering the drawings, the specification, and the claims. Furthermore, it should be noted that the language used in this specification has been chosen primarily for readability and instructional purposes and may not be chosen to describe or limit the subject matter of the invention.

[0124] The foregoing description of the embodiments of the present invention is provided for illustrative purposes only. It is not intended to limit the invention to the exact form disclosed or to make it without omission. Those skilled in the art will understand that many modifications and variations are possible in light of the foregoing disclosure.

[0125] Therefore, the scope of the present invention is not limited by the detailed description but by any of the claims of the application based thereon. Accordingly, the disclosure of embodiments of the present invention is illustrative and does not limit the scope of the present invention as set forth in the following claims.

Claims

1. In a digital textile printing system for knit fabrics, A conveying device comprising a conveying belt that receives a knitted fabric at a supply location and conveys the knitted fabric received through an upper surface while supporting it along a conveying path; A Webster guide that receives the knit fabric from the outside, unfolds the received knit fabric, and supplies it to the conveyor belt; and It includes a press roller positioned at the above supply location and guiding the knit fabric supplied from the Webster guide to the upper surface of the conveyor belt, The above Webster Guide is, An unwinder unit for unfolding knit fabric supplied from the outside; A fabric supply unit that supplies the knit fabric unfolded by the above unwinder unit to the above conveyor belt; and It includes a control unit that controls the operation of the above-mentioned fabric supply unit, and A digital textile printing system for knit fabric, wherein the above Webster guide feeds the knit fabric to the feed position at a position higher than the press roller.

2. In Paragraph 1, The above unwinder unit is, A pair of support rollers that each rotate freely around a rotation axis parallel to one another and support the lower side of the knit fabric; and A digital textile printing system for knit fabric, comprising a first spreading roller that rotates around a rotation axis parallel to the pair of support rollers, contacts the portion of the knit fabric supported by the pair of support rollers, and spreads the knit fabric.

3. In Paragraph 2, The above-mentioned first spreading roller is, A digital textile printing system for knit fabrics, positioned between the above-mentioned pair of support rollers and configured so that the surface contacts the knit fabric on the upper side of the knit fabric portion.

4. In Paragraph 2, The above-mentioned first spreading roller is, A digital textile printing system for knit fabrics, wherein a screw-shaped pattern extending from the center toward both ends of the rotation axis of the first expansion roller is formed on the surface.

5. In Paragraph 3, A digital textile printing system for knit fabric, further comprising a second spreading roller positioned adjacent to the press roller, rotating about a rotation axis parallel to the first spreading roller, spreading out the portion of the knit fabric supplied to the supply position and transferring it to the press roller.

6. In Paragraph 5, The above second spreading roller is, A digital textile printing system for knit fabrics configured such that a surface contacts the knit fabric at the lower side of the knit fabric portion supplied to the above supply position.

7. In Paragraph 1, The above fabric supply unit is, A drive roller that rotates around a drive shaft and has a rubber member mounted on its surface; and It includes a drive motor that rotates the above drive roller, and A digital textile printing system for knit fabric, wherein the above-described drive roller supports the lower side of the knit fabric and is configured to transfer the knit fabric to the transfer device through a rotational movement.

8. In Paragraph 7, A digital textile printing system for knit fabrics, wherein the above-described drive roller is movable in both directions along the drive shaft.

9. In Paragraph 8, The above fabric supply unit is, A moving part that moves the above-mentioned drive roller along the drive shaft; and It further includes a guide sensor for detecting the position of the knit fabric relative to the drive roller on the drive shaft, and A digital textile printing system for knit fabrics, wherein the control unit controls the operation of the moving unit based on detection information of the guide sensor.

10. In Paragraph 1, It further includes a fabric detection unit disposed between the press roller and the fabric supply unit, which detects whether the knit fabric is located at a detection position lower than the conveyor belt. A digital textile printing system for knit fabric, wherein the control unit is configured to stop the operation of the fabric supply unit when it is determined that the knit fabric is located at the detection position, and to resume the operation of the fabric supply unit when it is determined that the knit fabric is not located at the detection position.

11. In Paragraph 10, The fabric sensing unit above is, An optical laser that irradiates light; and It includes a light detector that receives light irradiated by the optical laser, and A digital textile printing system for knit fabric, wherein the control unit determines that the knit fabric is located at a detection position if light is not received by the light detection unit.

12. In Paragraph 10, It further includes a support frame that supports the lower side of the above Webster guide, and A digital textile printing system for knit fabrics, wherein the fabric sensing unit is installed on the support frame.

13. In Paragraph 10, It further includes an additional fabric sensing unit located above the fabric sensing unit, and A digital textile printing system for knit fabric, wherein the control unit is configured to stop the operation of the fabric supply unit when it is determined that the knit fabric is not located at the detection position of the additional fabric detection unit, and to resume the operation of the fabric supply unit when it is determined that the knit fabric is located at the detection position of the additional fabric detection unit.

14. In Paragraph 10, A digital textile printing system for knit fabrics, further comprising a limit sensor at the bottom of the fabric detection unit to perform the role of the fabric detection unit when the fabric detection unit is not operating normally.

15. In Paragraph 1, The above press roller is movable in the up and down direction, and A digital textile printing system for knit fabrics configured to supply the knit fabric in close contact with the upper surface of the conveyor belt.

16. In Paragraph 1, A digital textile printing system for knit fabric, further comprising a textile printing device for printing on the knit fabric at a printing position located on the upper part of the conveyor belt and on the conveyor path.

17. In Paragraph 1, The above conveyor belt forms a closed loop and rotates along the conveyor path, and A digital textile printing system for knit fabrics, wherein an adhesive material to which the knit fabric is adhered is applied to the surface of the above-mentioned conveyor belt.

Images