CN218020809U

CN218020809U - Ink jet printing system with external drying function

Info

Publication number: CN218020809U
Application number: CN202222025159.1U
Authority: CN
Inventors: 汤振华
Original assignee: Guangzhou Kingtau Machinery & Electronics Equipment Co ltd
Current assignee: Guangzhou Kingtau Machinery & Electronics Equipment Co ltd
Priority date: 2022-08-02
Filing date: 2022-08-02
Publication date: 2022-12-13
Anticipated expiration: 2032-08-02

Abstract

The utility model relates to an ink jet printing field discloses an ink jet printing system with external stoving. The system comprises an unwinding device, a roller printing device, a first drying device and a winding device, wherein a printing medium is unfolded by the unwinding device, subjected to ink jet printing by the roller printing device, dried by the first drying device, and finally coiled by the winding device. The unwinding device, the first drying device and the winding device are all located on the same side of the roller printing device, and the printing medium enters and leaves from the same side of the roller printing device. The scheme is used for solving the problem that the image-text is fuzzy after the undried ink on the surface of the printing medium is rubbed, and the effect of improving the quality of image-text ink-jet printing is achieved.

Description

Ink jet printing system with external drying function

Technical Field

The utility model relates to an inkjet printing field, more specifically relates to an inkjet printing system with external stoving.

Background

Ink jet printing is a contactless, pressure-free, plate-free printing. The principle of ink-jet printing is that firstly, the image-text information to be processed is input into an electronic computer, and after being edited and processed by an electronic color separation system, the stored image-text information is input into an ink-jet printer; under the control of an electronic computer, a nozzle of a printing nozzle sprays atomized tiny ink drops to the surface of a printing medium, and the ink drops directly form images on the surface of the printing medium according to the charge effect, so that image-text printing is realized. There are a flat printer and a roll printer according to a driving mechanism of a printing medium. The roller printer has advantages of fast printing speed, good color registration, etc., and is gradually applied to large-scale commercial printing.

The general structure of the roller type printer comprises a roller, a linear moving platform and a printing spray head assembly, wherein the roller is positioned below the linear moving platform and the printing spray head assembly, and a printing medium is wound and conveyed on the surface of the roller; the linear moving platform drives the printing nozzle assembly to adjust the distance between the printing nozzle assembly and the printing medium; the printing spray head assembly comprises a printing spray head array consisting of a plurality of printing spray heads and a spray head tray for mounting the printing spray head array; when the printing medium passes through the lower part of the printing spray head component, the fixed printing spray head component continuously sprays ink to finish image-text printing.

Inks used for inkjet printing are generally classified into oil-based inks, aqueous inks, and UV inks. The oil-based ink is an ink in which a water-insoluble solvent is used as a dissolving chromophore, the water-based ink is an ink in which water and a water-soluble solvent are used as dissolving chromophores, and the oil-based ink or the water-based ink is a solvent ink, and the ink adheres a pigment or a dye to a printing medium through permeation and evaporation of the solvent on the printing medium. UV inks are inks that use ultraviolet light of different wavelengths and different energies to cause ink droplets to film and dry under ultraviolet radiation. In the case of solvent inks, particularly aqueous inks, after the printing medium is printed, it is necessary to dry the printing medium for a long time to sufficiently adhere the ink to the surface. In the prior art, a roller printer using water-based ink is limited by the structure, and usually only a small drying device can be built in the roller printer, so that the drying process of the water-based ink is accelerated by the drying device to make up for the short printing speed of the roller printer. Because the roller running speed of the roller type printer and the ink jet speed of the printing nozzle assembly are high, the printing medium which completes the image-text printing quickly passes through the drying device. The effective drying time of the water-based ink on the printing medium is short, and the water-based ink is immediately conveyed to the next link without being sufficiently dried. The printing surface of the printing medium is rubbed by external force, so that part of the water-based ink on the surface of the printing medium is deviated and dispersed, the image and text are blurred, and the quality of ink-jet printing is seriously influenced. With the increase of the printing speed, the widening of the printing breadth, the increase of the image-text coverage rate and the deepening of the image-text color of the roller type printer and the increase of the total amount of the aqueous ink in the unit length of the printing medium, the lower the drying degree of the aqueous ink is, the more serious the image-text blurring condition is.

SUMMERY OF THE UTILITY MODEL

The utility model aims at overcoming at least one of the not enough of above-mentioned prior art, provide an inkjet printing system with external stoving for solve the not dry ink in print medium surface and suffer the back of rubbing, lead to the fuzzy problem of its picture and text, reach the effect that promotes picture and text inkjet printing quality.

The utility model provides a technical scheme who takes, an ink jet printing system with external stoving, including unwinding device, roller printing device, first drying device and coiling mechanism, print medium is launched by unwinding device, carries out ink jet printing through roller printing device, carries out the drying through first drying device again, carries out the lapping by coiling mechanism at last. The unwinding device, the first drying device and the winding device are all located on the same side of the roller printing device, and the printing medium enters and leaves from the same side of the roller printing device.

In this scheme, use roller printing device as the benchmark, the axial of its roller is the fore-and-aft direction, and the horizontal direction is left right direction, and vertical direction is upper and lower direction.

In the scheme, the printing medium is wound on the roller of the roller printing device, enters and leaves from the same side of the roller, is tensioned and reversed by the roller, and can enter the first drying device arranged on the same side to be dried without other devices for reversing or supporting. Therefore, in the process that the printing surface of the printing medium is conveyed to the first drying device after ink jet printing, undried ink on the surface of the printing medium can be effectively prevented from being rubbed by external force. Furthermore, the first drying device is arranged independently of the roller printing device, and the first drying device is not limited by the structure of the roller printing device. The first drying device can calculate the temperature and the effective length of the first drying device required to provide drying according to the drying speed of the ink, the printing speed of the roller printing device and the printing breadth. The first drying means, which is externally disposed without limitation, can ensure sufficient drying of the ink on the surface of the printing medium passing through the inside thereof. The first drying device may refer to a related standard product in the related art, and its inner structure is not in contact with the printing surface of the printing medium. Therefore, the undried ink on the surface of the printing medium can be gradually and sufficiently dried in a non-contact condition during the printing surface of the printing medium passes through the first drying device. The printing medium of this scheme gets into and leaves with one side from roller printing device, and the printing medium is after ink-jet printing, and direct output carries out abundant drying to the external first drying device who places in with one side, and then is used for solving the not dry ink in printing medium surface and suffers the back of rubbing, leads to the fuzzy problem of its picture and text, reaches the effect that promotes picture and text ink-jet printing quality.

In this embodiment, the printing medium is stored in a roll form. The printing medium can be input into the roller printing device for ink jet printing after being unfolded by the unwinding device, and is rolled by the winding device after the image-text printing is completed. The unwinding device and the winding device can refer to standard products in the prior art. The unwinding device and the winding device realize the automatic input and output of the printing medium of the ink jet printing system. Moreover, first drying device can adopt the modularized design, and its length can carry out nimble adjustment according to the required drying time of ink.

Preferably, the unwinding device comprises a first sensor and/or a second sensor, and the winding device comprises a first sensor and/or a second sensor; the first sensor is used for obtaining the thickness of the roll material by measuring the roll surface position of the printing medium; the second sensor is used for obtaining the offset of the roll stock by measuring the edge position of the printing medium.

In the scheme, the printing medium is placed on a rotating shaft of the unwinding device or the winding device in a roll material mode, and the first sensor is fixed at a certain position far away from the rotating shaft. The first sensor measures the position of the winding surface of the printing medium, namely the distance between the outer surface of the winding material and the first sensor, and then difference calculation is carried out, so that the thickness of the winding material can be obtained. The first sensor is arranged on the unwinding device, and the system can obtain the allowance of the unprinted printing medium so as to be convenient for feeding and supplementing in time; the first sensor is arranged on the winding device, and the system can obtain the stock of the printed printing medium so as to timely discharge and pack. Further, after the printing medium leaves the open roll or before the printing medium enters the winding device, the printing medium being transported may be offset from the roll on the rotating shaft. The second sensor obtains the offset of the printing medium by measuring the position deviation of the two side edges of the printing medium in conveying, and further obtains the offset of the coil stock on the rotating shaft, which needs to be adjusted, so as to realize the deviation rectifying function of the system. The unwinding device is provided with a second sensor, so that the unprinted printing medium can be centrally input to the roller printing device; the winding device is provided with a second sensor, so that the printed printing medium can be orderly rolled.

Preferably, the first drying device comprises a box body, and a heater, a cross flow fan and a driving roller which are arranged in an inner cavity of the box body; the transverse flow fans and the transmission rollers are arranged up and down oppositely, and the transmission rollers and the transverse flow fans are arranged at intervals along the length direction of the box body; the printing medium sequentially passes through gaps between the driving rollers and the cross flow fans.

Further, the box body sequentially comprises a horizontal section and an inclined section along the conveying direction of the printing medium, the ratio of the length of the inclined section to the length of the horizontal section is not less than 2, and the inclination angle of the inclined section is 25-30 degrees.

In the scheme, the heater is used for heating air in the closed space of the box body. The cross flow fan and the driving roller are positioned to correspond to each other, and the printing medium passes through a gap between the cross flow fan and the driving roller. The number of the driving rollers is larger than that of the driving rollers equal to the number of cross flow fans. When the printing surface of the printing medium faces downwards, the cross flow fan is arranged below, and the driving roller is arranged above; when the print side of the print medium is facing up, the cross flow fan is on top and the drive roller is under. The cross flow fan continuously blows hot air in the box body to the printing surface of the printing medium so as to dry ink on the surface of the printing medium; the driving roller supports the back surface of the printing medium to prevent the printing medium from being deformed. After the hot air is blown to the print medium, the hot air rises and gathers in the upper portion of the case. The box body of the inclined section can enable hot air at a lower position to be reused and blown to printing media at a higher position, so that the heat energy utilization efficiency in the box body is improved, and the power of the first drying device is reduced.

Further, the box body also comprises a heat exchange channel and a heat exchanger. The heat exchanger is communicated with the inner cavity of the box body through the heat exchange channel and is used for adjusting the temperature of the inner cavity of the box body so as to keep the temperature in the optimal ink drying temperature range.

Preferably, the winding device further comprises a guide belt, and the first drying device further comprises a traction mechanism arranged in an inner cavity of the box body; and the guide belt is unfolded by the winding device, is clamped by the traction mechanism and is conveyed to the other side of the box body along the reverse direction of the conveying direction of the printing medium, and sequentially passes through gaps between the plurality of driving rollers and the plurality of cross flow fans.

In this scheme, when printing for the first time, print medium expandes from unwinding device, need just can become to wrap up in coiling mechanism behind roller printing device and the first drying device. And the length of the first drying device is usually longer in order to match the high-speed printing of the roller printing device. Therefore, the print medium will be wasted for a long period of time and cannot be ink-jet printed. In addition, under the state that does not pull, need open first drying device's box, the internal structure with print media passes first drying device manually, and the process is loaded down with trivial details. The provision of inexpensive guide belts and traction mechanisms can effectively address the above problems. The guiding belt is arranged on the winding device, and the traction mechanism is arranged in a box body of the first drying device. After the guide belt is unfolded, the guide belt is clamped and driven by a traction mechanism, moves along the direction opposite to the conveying direction of the printing medium, sequentially passes through a plurality of driving rollers and a plurality of cross flow fans, and finally reaches the input end of the first drying device. The guide belt can be further reversely wound around the roller printing device and then connected with the unfolded printing medium at one end of the unwinding device.

Optionally, a preheating device is further arranged between the unwinding device and the roller printing device, and the preheating device is used for preheating the passing printing medium. When printing at a high speed, the printing medium passes through the first heating roller and the second heating roller on the roller printing device quickly, the effective heating time of the printing medium is too short, sufficient heating is difficult to obtain, and the preheating device can effectively make up for the deficiency. The pre-heating device, the first heating roller and the second heating roller heat the printing medium in stages so that the printing medium reaches an ideal working temperature.

Preferably, the roller printing device comprises a roller, a linear moving assembly and a printing spray head assembly; the roller is used for winding and conveying the printing medium; the linear moving assembly is used for driving the printing nozzle assembly and adjusting the distance between the printing nozzle assembly and the surface of the roller; the printing nozzle assembly is used for carrying out ink jet printing on a printing medium. The printing spray head assembly comprises a spray head tray and printing spray heads arranged on the spray head tray, the printing spray heads are distributed on the spray head tray in a plurality of rows in parallel, and the printing spray heads on two adjacent rows are overlapped in a staggered manner; the printing nozzle is obliquely arranged relative to the nozzle tray; a plurality of rows of printing nozzles are arranged around the surface of the roller, the lower surfaces of the plurality of rows of printing nozzles are combined to form a concave ink jet surface, and each surface of the ink jet surface is tangent to the surface of the roller.

The specific numerical calculation of the inclination angle can be obtained by the following simplified relationship of the head tray and the printing heads. The spray head tray is provided with a first reference line, and the first reference line points to the circle center of the surface of the roller; the jet hole of the printing nozzle is provided with a second reference line, and the second reference line points to the ink jetting direction of the jet hole; an included angle between the first reference line and the second reference line is a deflection angle phi, and the printing spray head is obliquely arranged relative to the first reference line at the deflection angle phi;

the calculation formula of the deflection angle phi is as follows:

wherein, L is the distance from the jet orifice to the first reference line; h is the height from the spray head tray to the surface of the roller; alpha is the included angle between the moving direction of the spray hole and the first reference line; r is the radius of the roller surface.

Preferably, the roller printing device further comprises a first heating roller, or a first heating roller and a second heating roller; the first heating roller is used for heating the printing surface of the printing medium; the second heating roller is used for heating the back of the printing medium; the printing medium is sequentially wound around the first heating roller and the roller, or the printing medium is sequentially wound around the second heating roller, the first heating roller and the roller. The printing medium is heated and then is subjected to ink jet printing, so that the ink adhesion and the solvent drying are facilitated, the color quality of the image-text is improved, and the subsequent drying requirement on the first drying device is reduced. The two sides of the printing medium are heated, so that the phenomenon that the printing medium is folded and deformed due to heating can be avoided.

Optionally, the roller printing device further comprises a first UV curing assembly and a second UV curing assembly, and the first UV curing assembly and the second UV curing assembly are used for curing the ink attached to the surface of the printing medium in a divided manner; the plurality of groups of first UV curing assemblies are respectively arranged on one side of the nozzle tray of the plurality of groups of printing nozzle assemblies; the second UV curing assembly is arranged far away from the printing spray head assembly; the printing medium sequentially passes through the plurality of groups of printing spray head assemblies, the plurality of groups of first UV curing assemblies and the second UV curing assemblies.

In this scheme, to UV ink, then need adopt UV solidification subassembly to solidify it. In the ink-jet printing, color separation and multiple printing are adopted, and the printing nozzle assemblies are generally arranged into multiple groups, and each group of printing nozzle assemblies completes ink-jet printing of one color. When the printing medium sequentially passes through the plurality of groups of printing nozzle assemblies, when the ink-jet printing of one color is completed, the first UV curing assembly pre-cures the UV ink of the first UV curing assembly so as to prevent the un-dried UV inks of different colors from interfering with each other and causing unclear pictures and texts. After the printing medium is subjected to the inkjet printing of all colors, the second UV curing assembly is used for carrying out final complete curing on all colors of UV ink.

Preferably, the roller printing device further comprises an ion air bar for removing static electricity on the surface of the printing medium; the printing medium passes through the ion air bar and the printing spray head assembly in sequence.

Preferably, the roll printing device further comprises a tension roller assembly for adjusting the tension of the printing medium entering the roll printing device. The tension roller may move up and down to tension or loosen the printing medium wound thereon.

Optionally, the roller printing device further comprises a second drying device, and the second drying device is used for pre-drying the printing medium subjected to ink jet printing.

Compared with the prior art, the beneficial effects of the utility model are that:

the printing medium of this scheme gets into and leaves with one side from roller printing device, and the printing medium is after ink-jet printing, and direct output carries out abundant drying to the external first drying device who places in with one side, and then is used for solving the not dry ink in printing medium surface and suffers the back of rubbing, leads to the fuzzy problem of its picture and text, reaches the effect that promotes picture and text ink-jet printing quality.

Drawings

Fig. 1 is a plan view of embodiment 1 of the present invention.

Fig. 2 is a schematic view of the print heads in the embodiment 2 of the present invention in a staggered and overlapping distribution.

Fig. 3 is a schematic cross-sectional view of embodiment 2 of the present invention when two rows of printing heads are used.

Fig. 4 is a schematic cross-sectional view of embodiment 2 of the present invention when three rows of printing heads are used.

Fig. 5 is a schematic diagram illustrating calculation of a deflection angle Φ (α = 0) of a print head having a single row of orifices according to embodiment 2 of the present invention.

Fig. 6 is a schematic view of calculating a deflection angle Φ (α ≠ 0) of a print head with a single row of orifices according to embodiment 2 of the present invention.

Fig. 7 is a schematic diagram illustrating calculation of a deflection angle Φ (α ≠ 0) of a print head having a plurality of rows of orifices according to embodiment 2 of the present invention.

Fig. 8 is a cross-sectional view of a head tray according to embodiment 2 of the present invention.

Fig. 9 is a side view of embodiment 2 of the present invention.

Fig. 10 is a structural diagram of a first viewing angle in embodiment 2 of the present invention.

Fig. 11 is a structural diagram of a second viewing angle in embodiment 2 of the present invention.

Fig. 12 is a cross-sectional view of embodiment 3 of the present invention.

Fig. 13 is a schematic view of the connection between the printing medium and the guide belt according to embodiment 1 of the present invention.

Description of reference numerals 1: the roller printing device comprises a roller printing device 100, an unreeling device 200, a first sensor 210, a second sensor 220, a first drying device 300, a box body 310, a horizontal section 311, an inclined section 312, a cross flow fan 320, a driving roller 330, a heat exchanger 340, a traction mechanism 350, a second drying device 400, a reeling device 500 and a preheating device 600.

Description of reference numerals 2: the printing head comprises a printing head assembly 110, a head tray 111, a printing head 112, spray holes 113, a first mounting groove 114, a second mounting groove 115, a first reference line 121, a second reference line 122, a third reference line 123, a fourth reference line 124, a roller 130, a linear moving assembly 140, a servo motor 141, a lead screw nut 142, a slider 143, a guide rail 144, a connecting plate 145, a head cleaning assembly 150, a negative pressure suction nozzle 151, a reciprocating drive mechanism 152, a first heating roller 161, a second heating roller 162, a first UV curing assembly 171, a second UV curing assembly 172, an ion wind bar 180 and a tension roller assembly 190.

Detailed Description

The drawings of the present invention are for illustration purposes only and are not to be construed as limiting the invention. For a better understanding of the following embodiments, certain features of the drawings may be omitted, enlarged or reduced, and do not represent the size of an actual product; it will be understood by those skilled in the art that certain well-known structures in the drawings and descriptions thereof may be omitted.

Example 1

As shown in fig. 1, the present embodiment is an inkjet printing system with external drying, which includes an unwinding device 200, a roller printing device 100, a first drying device 300, and a winding device 500, wherein a printing medium is unwound by the unwinding device 200, subjected to inkjet printing by the roller printing device 100, dried by the first drying device 300, and finally wound by the winding device 500. The unwinding device 200, the first drying device 300, and the winding device 500 are all located at the same side of the roll printing device 100, and the printing medium enters and leaves from the same side of the roll printing device 100.

In this scheme, use roller printing device 100 as the benchmark, the axial of its roller is the fore-and-aft direction, and the horizontal direction is left and right sides direction, and vertical direction is upper and lower direction.

In the scheme, the printing medium is wound on the roller of the roller printing device 100, enters and leaves from the same side of the roller, is tensioned and reversed by the roller, and can enter the first drying device 300 arranged on the same side to be dried without other devices for reversing or supporting. Therefore, in the process of conveying the printing surface of the printing medium to the first drying device 300 after the ink-jet printing, the undried ink on the surface of the printing medium can be effectively prevented from being rubbed by external force. Furthermore, the first drying device 300 is provided independently of the roll printing device 100, and the first drying device 300 is not necessarily limited by the structure of the roll printing device 100. The first drying device 300 can calculate the temperature and effective length required for providing drying according to the drying speed of the ink, the printing speed of the roller printing device 100 and the printing width. The first drying device 300, which is externally disposed without limitation, can ensure sufficient drying of ink on the surface of the printing medium passing through the inside thereof. The first drying device 300 may refer to a related standard product in the related art, and its inner structure is not in contact with the printing surface of the printing medium. Therefore, the undried ink on the surface of the printing medium can be dried gradually and sufficiently in a non-contact condition while the printing surface of the printing medium passes through the first drying device 300. The printing medium of this scheme gets into and leaves with one side from roller printing device, and the printing medium is after ink-jet printing, and direct output carries out abundant drying to the external first drying device who places in with one side, and then is used for solving the not dry ink in printing medium surface and suffers the back of rubbing, leads to the fuzzy problem of its picture and text, reaches the effect that promotes picture and text ink-jet printing quality.

In this embodiment, the printing medium is stored in a roll form. The printing medium can be input into the roller printing device 100 for inkjet printing after being unwound by the unwinding device 200, and is rolled up by the winding device 500 after the image-text printing is completed. The unwinding device 200 and the winding device 500 can refer to standard products in the prior art. The unwinding device 200 and the winding device 500 realize automatic input and output of the printing medium of the inkjet printing system. Furthermore, the first drying device 300 may be of a modular design, and the length thereof can be flexibly adjusted according to the drying time required by the ink.

In this embodiment, the winding device 500, the first drying device 300, and the unwinding device 200 are sequentially located on the left side of the roller printing device 100 from left to right. The printing medium enters from the left side of the roller printing device 100, and after image-text printing is completed, the printing medium is folded back and still leaves from the left side of the roller printing device 100. The unwinding device 200 and the winding device 500 are driven by an ac servo motor to match the rotation of the roller 130, so as to prevent the printing medium from being pulled.

Preferably, the unwinding device 200 includes a first sensor 210 and/or a second sensor 220, and the winding device 500 includes the first sensor 210 and/or the second sensor 220; the first sensor 210 is used for obtaining the thickness of the roll stock by measuring the roll surface position of the printing medium; the second sensor 220 is used to obtain the offset of the web by measuring the edge position of the print medium.

In this embodiment, the printing medium is placed on the rotating shaft of the unwinding device 200 or the winding device 500 in a roll material manner, and the first sensor 210 is fixed at a position away from the rotating shaft. The first sensor 210 measures the roll surface position of the printing medium, i.e., the distance between the outer surface of the roll and the roll, and then calculates the difference value, so as to obtain the thickness of the roll. The first sensor 210 is installed on the unwinding device 200, and the system can obtain the remaining amount of the unprinted printing medium, so as to timely feed and supplement; the first sensor 210 is installed on the winding device 500, and the system can obtain the stock of the printed printing medium, so as to timely feed and pack. Furthermore, after the printing medium leaves the unwinding device 200 or before the printing medium enters the winding device 500, the printing medium being transported may deviate from the roll material on the spindle. The second sensor 220 obtains the offset of the printing medium by measuring the position deviation of the two side edges of the printing medium during conveying, and further obtains the offset of the roll material on the rotating shaft, which needs to be adjusted, so as to realize the deviation rectifying function of the system. The unwinding device 200 is provided with a second sensor 220, so that an unprinted printing medium can be centrally input to the roll printing device 100; the winding device 500 is provided with the second sensor 220, so that the printed printing medium can be orderly rolled.

In this embodiment, the first sensor 210 is a kirschner distance sensor, and is respectively installed below the unwinding device 200 and the winding device 500. The second sensor 220 of the unwinding device 200 is installed at an input end of the roll printing device 100, and the second sensor 220 of the winding device 500 is installed at an input end thereof.

Preferably, the first drying device 300 includes a cabinet 310, and a heater, a cross flow fan 320 and a driving roller 330 disposed in an inner cavity of the cabinet 310; the cross flow fan 320 and the driving roller 330 are arranged up and down oppositely, and a plurality of driving rollers 330 and a plurality of cross flow fans 320 are arranged at intervals along the length direction of the case 310; the printing medium sequentially passes through gaps between the plurality of driving rollers 330 and the plurality of cross flow fans 320.

Further, the box 310 sequentially comprises a horizontal section 311 and an inclined section 312 along the conveying direction of the printing medium, the ratio of the length of the inclined section 312 to the length of the horizontal section 311 is not less than 2, and the inclination angle of the inclined section 312 is 25-30 °.

In this embodiment, the heater is used to heat the air in the enclosed space of the box 310. The cross flow fan 320 and the driving roller 330 are positioned corresponding to each other, and the printing medium passes through a gap between the cross flow fan 320 and the driving roller 330. The number of the driving rollers 330 is equal to or greater than the number of the cross flow fans 320. With the print side of the print medium facing down, cross flow fan 320 is down and drive roller 330 is up; when the printing surface of the printing medium is facing up, the cross flow fan 320 is on top and the driving roller 330 is under. The cross flow fan 320 continuously blows hot air inside the cabinet 310 toward the printing surface of the printing medium to dry the ink on the surface thereof; the driving roller 330 supports the back surface of the printing medium to prevent the printing medium from being deformed. After the hot air is blown to the printing medium, it rises and gathers on the upper portion of the case 310. The box 310 of the inclined section 312 may enable the hot air at a lower position to be reused and blown to the printing medium at a higher position, thereby improving the heat energy utilization efficiency in the box 310 and reducing the power of the first drying device 300.

Further, the case 310 further includes a heat exchange passage and a heat exchanger 340. The heat exchanger 340 is communicated with the inner cavity of the box 310 through a heat exchange channel, and the heat exchanger 340 is used for adjusting the temperature of the inner cavity of the box 310 to maintain the temperature within an optimal ink drying temperature range.

In this embodiment, the cross flow fans 320 correspond to the driving rollers 330 one to one, and the number of the cross flow fans 320 is the same, and the driving rollers 330 are located below and above. The heater is integrated on the cross flow fan 320. The arrangement interval of the plurality of cross flow fans 320 and the plurality of driving rollers 330 is 800 to 1000mm. The cross flow fan 320 and/or the driving roller 330 may be detachably taken out from the front and rear sides of the cabinet 310 to facilitate daily maintenance. The printing medium enters from the input end of the right side of the cabinet 310, sequentially passes through the gaps between the plurality of driving rollers 330 and the plurality of cross-flow fans 320, and is dried, and finally exits from the output end of the left side of the cabinet 310.

As shown in fig. 13, preferably, the winding device 500 further includes a guide belt, and the first drying device 300 further includes a traction mechanism 350 disposed in an inner cavity of the box 310 thereof; the guide tape is unwound by the winding device 500, is clamped by the traction mechanism 350, and is transported to the other side of the box 310 along the direction opposite to the transportation direction of the printing medium, and sequentially passes through gaps between the plurality of driving rollers 330 and the plurality of cross flow fans 320.

In this scheme, when printing for the first time, the printing medium is unwound from the unwinding device 200, and needs to pass through the roller printing device 100 and the first drying device 300 before being wound on the winding device 500. And the length of the first drying device 300 is generally long in order to match the high-speed printing of the roll printing device 100. Therefore, the print medium will be wasted for a long period of time and cannot be ink-jet printed. In addition, in a state without traction, the cabinet 310 of the first drying device 300 needs to be opened, and the printing medium is manually inserted through the internal structure of the first drying device 300, which is a cumbersome process. The provision of an inexpensive leader and pull mechanism 350 effectively solves the above problems. The guide belt is disposed on the winding device 500, and the drawing mechanism 350 is disposed in the case 310 of the first drying device 300. After being unfolded, the guide belt is clamped and driven by the traction mechanism 350, moves in the direction opposite to the conveying direction of the printing medium, sequentially passes through the plurality of driving rollers 330 and the plurality of cross flow fans 320, and finally reaches the input end of the first drying device 300. The guide tape may be subsequently wound around the roll printing apparatus 100 in a further reverse direction, and then may be docked with the unwound printing medium at one end of the unwinding device 200.

In this embodiment, the guiding tape may be pre-wound on the rotating shaft of the winding device 500, or may be separately wound and juxtaposed on one side of the rotating shaft. The guide belt may be a single belt and the same width as the printing medium, or two or more belts. When the device is used, one end of the guide belt is fixed on the rotating shaft of the winding device 500, and the other end of the guide belt is connected with a printing medium in a connection mode. The drawing mechanism 350 may be a robot installed on the front and rear sides of the cassette 310, and the robot may grip the guide tape to move along the transfer trace of the printing medium. The guide belt is docked with the printing medium at the right side of the first drying device 300.

Preferably, a preheating device 600 is further disposed between the unwinding device 200 and the roller printing device, and the preheating device 600 is configured to preheat a passing printing medium. When printing at a high speed, the printing medium passes through the first heating roller and the second heating roller on the roller printing device quickly, the effective heating time of the printing medium is too short, sufficient heating is difficult to obtain, and the preheating device 600 can effectively make up for the deficiency. The preheating device 600, the first heating roller, and the second heating roller heat the printing medium in stages, so that the printing medium reaches an ideal operating temperature.

Optionally, a second drying device 400 is further disposed on the roller printing device 100, and the second drying device 400 is configured to pre-dry the printing medium after completing the inkjet printing.

Example 2

As shown in fig. 2, 3 and 4, the present embodiment is a printing head assembly with a deflection angle, which includes a head tray 111 and printing heads 112 mounted thereon, wherein the printing heads 112 are arranged in a plurality of rows on the head tray 111, and the printing heads 112 on two adjacent rows are overlapped in a staggered manner. The print head 112 is installed obliquely with respect to the head tray 111; rows of print heads 112 are arranged around a drum surface, and the lower surfaces of rows of print heads 112 combine to form a concave ink ejection surface, each side of the ink ejection surface being tangential to the drum surface.

In this embodiment, the length direction of the head tray 111 is the front-rear direction, the width direction thereof is the left-right direction, and the height direction thereof is the up-down direction. The ink ejection direction of the print head 112 is generally taken in its normal direction with the center position of the lower surface of the print head 112. Each row of print heads 112 is installed to be inclined with respect to head tray 111, and the ink ejecting direction of each row of print heads 112 is inclined with respect to a reference line of head tray 111, and the ink ejecting direction of each row of print heads 112 has a different inclination angle. Rows of print heads 112 are looped over the surface of the roll. The lower surfaces of the rows of print heads 112 are no longer planar and combine to form a concave ink ejection surface. When the nozzle tray 111 drives the printing nozzle 112 to be close to the surface of the roller, and the distance between the lower surface of the printing nozzle 112 and the surface of the roller is zero, each surface of the ink-jet surface is tangent to the surface of the roller. The ink ejection surface corresponds to a portion of the circumscribing polygon of the roller surface. This scheme is through installing every row of shower nozzle for the inclination of shower nozzle tray with the difference, makes the centre of a circle that the inkjet direction of printing the shower nozzle can point to the roller surface, and then solves the problem that the unable perpendicular to roller surface simultaneously of the crisscross shower nozzle of printing that overlaps of multirow reaches the effect that promotes the whole printing quality of printing shower nozzle subassembly.

As shown in fig. 5 to 7, specific numerical calculation for the inclination angle can be obtained by the following simplified relationship of the head tray 111 and the printing heads 112. The spray head tray 111 is provided with a first reference line 121, and the first reference line 121 points to the center of the roller surface; the jet orifice 113 of the print head 112 has a second reference line 122, and the second reference line 122 points to the ink ejection direction of the jet orifice 113; an included angle between the first reference line 121 and the second reference line 122 is a deflection angle phi, and the printing nozzle 112 is obliquely installed relative to the first reference line 121 at the deflection angle phi;

the calculation formula of the deflection angle phi is as follows:

In this embodiment, the first reference line 121 of the head tray 111 may be a center line of the head tray 111, with the first reference line 121 being a reference line. After the printing nozzles 112 are obliquely installed at the deflection angle phi relative to the first reference line 121 of the nozzle tray 111, as long as the first reference line 121 points to the center of the surface of the roller, the ink jetting direction of each row of printing nozzles 112 can be ensured to point to the center of the surface of the roller, and each row of printing nozzles 112 is perpendicular to the surface of the roller at the same time. The second reference line 122 points in the ink ejection direction of the nozzle 113 starting from the center of the nozzle 113 of the print head 112. When the orifices 113 of a single print head 112 are in a single row, the second reference line 122 is the ink ejection direction of the row of print heads 112, and the deflection angle Φ is the inclination angle of the row of print heads 112 relative to the head tray 111. When the plurality of rows of the nozzles 113 of the single print head 112 are provided, each row of the nozzles 113 has a second reference line 122, and a plurality of deflection angles Φ are calculated. Since the pitch of the plurality of rows of the nozzle holes 113 is short, an average value of the deflection angles Φ of the plurality of rows of the nozzle holes 113 or a deflection angle Φ of the middle position of the plurality of rows of the nozzle holes 113 can be calculated as the inclination angle at which the row of the print heads 112 is mounted with respect to the head tray 111. Within the tolerance, the ink jetting directions of the multiple rows of orifices 113 of the row of print heads 112 are all approximately perpendicular to the surface of the roll.

In this scheme, the height H from the nozzle tray to the surface of the roller varies within a certain range, and for each row of printing nozzles 112, a plurality of deflection angles phi can be calculated. Since the height H differs from the radius R of the cambered printing surface by several orders of magnitude, the variation range of the deflection angle Φ is small, and the average value thereof can be taken as the inclination angle of the row of printing heads 112 with respect to the head tray 111 within the error allowable range. When the height H from the spray head tray to the surface of the roller is zero, the lower surface of the spray head tray 111 and the imaginary extension plane thereof are tangent to the surface of the roller; the height H of the printhead tray to the roller surface corresponds to the working height of the print head 112. The distance L of the spray holes to the first reference line should be taken as the value when the height H of the spray head tray to the roller surface is zero. Furthermore, when the height H of the head tray 111 is adjusted, the head tray 111 does not necessarily move along the first reference line 121. When an included angle alpha between the moving direction of the spray hole and the first reference line is formed on the outer side of the surface of the roller, the included angle alpha takes a negative value; when an included angle alpha between the moving direction of the spray hole and the first reference line is formed on the inner side of the surface of the roller, the included angle alpha takes a positive value.

Preferably, the ratio between the radius R of the roller surface and the distance L of the orifice 113 to the first reference line 121 is: R/L is more than or equal to 10. For a print head 112 with multiple rows of orifices 113, the distance L from the orifices to the first reference line has a minimum value L _MIN And maximum value L _MAX . When calculating the R-L ratio, the distance L should be selected as L _MAX (ii) a Further, it is also necessary to satisfy R/(L) _MAX -L _MIN ) Is more than or equal to 20. On the one hand, when the R-L ratio differs by an order of magnitude, the numerical difference of the deflection angle Φ calculated by each row of orifices 113 of a single print head 112 is small, so that the average value of the deflection angles Φ of the rows of orifices 113 or the deflection angle Φ of the middle position of the rows of orifices 113 can be calculated as the inclination angle of the row of print heads 112 installed relative to the head tray 111. And the ink jetting directions of the multiple rows of jet holes 113 of the row of printing nozzles 112 are all approximately vertical to the surface of the roller within the tolerance range. On the other hand, each of the individual print heads 112 has an order of magnitude difference in R-L ratioThe distance between the rows of orifices 113 is correspondingly smaller, so that the heights of the rows of orifices 113 relative to the surface of the roller can be approximately equal, and the influence of the curvature of the surface of the roller on the spray quality of the printing nozzle 112 is further reduced.

Preferably, the moving direction of the head tray 111 includes an angle value with the first reference line 121, that is: the alpha is less than or equal to 20 degrees. When the head tray 111 is located at different heights H, the included angle α will affect the actual distance from the nozzle 113 of the print head 112 to the first reference line 121. When the included angle α takes a positive value, the included angle α increases the actual distance from the nozzle hole 113 to the first reference line 121; when the included angle α takes a negative value, the included angle α will decrease the actual distance from the nozzle 113 to the first reference line 121. This effect will be greater as the value of the angle a increases. In practical application, the value of the included angle α should not exceed 20 °, and the included angle α has a value range of [ -20 °,20 ° ].

Preferably, the deflection angle phi ranges from 1 deg. to 5 deg.. According to the calculation formula of the deflection angle phi, the deflection angle phi is comprehensively influenced by the distance L, the height H, the included angle alpha and the radius R. When the deflection angle phi of the orifices 113 of the print head 112 with respect to the first reference line 121 is between 1 deg. and 5 deg., the influence of the working height of the head tray 111 and the distribution of the orifices 113 of the print head 112 on the inclination angle of the print head 112 can be reduced. For example, for a print head 112 with multiple rows of orifices 113, when the print head 112 is mounted at an inclination of 3 ° with respect to the head tray 111, within an error range of 2 °, any row of orifices 113 on the print head 112 can be considered as perpendicular to the roll surface at any working height, with their ink ejection direction pointing to the center of the roll surface.

In this scheme, print shower nozzle 112 and for the installation of shower nozzle tray 111 slope, both connected modes include: the inclination angle is followed, namely the inclination angle of the printing nozzle 112 relative to the nozzle tray 111 can change under different conditions along with the change of the deflection angle, and the printing nozzle 112 is connected with the nozzle tray 111 through an automatic inclination angle adjusting device; the inclined angle is fixed, and the printing nozzle 112 is connected with the nozzle tray 111 through an inclined angle manual adjusting device (an adjusting sheet, an adjusting fastener and the like).

As shown in fig. 8 to 11, preferably, the inclination angle is fixed, and the head tray 111 is provided with a plurality of mounting grooves for fixing the printing heads 112; the center line of the mounting groove is a third reference line 123, and the third reference line 123 is inclined at a deflection angle phi with respect to the first reference line 121. The installation groove inclined at the deflection angle phi is processed in advance on the spray head tray 111, the printing spray head 112 is directly placed in the installation groove, the printing spray head 112 can be installed at the deflection angle phi in an inclined mode relative to the first reference line 121, and compared with a mode that the printing spray heads 112 are connected with the spray head tray one by one through adjusting sheets or adjusting fasteners, the installation efficiency and the installation accuracy of the inclined installation of the printing spray head 112 are greatly improved.

Further, the mounting groove comprises a first mounting groove 114 and a second mounting groove 115, the first mounting groove 114 and the second mounting groove 115 are symmetrically arranged along the first reference line 121, the intersection included angle of the lower surfaces of the first mounting groove 114 and the second mounting groove 115 is an installation included angle theta, and the installation included angle theta

The two rows of printing nozzles 112 can be spliced into an array of printing nozzles 112 by overlapping in a staggered manner, so that two rows of mounting grooves distributed in parallel are correspondingly arranged. The first and second mounting

grooves

114 and 115 are symmetrically disposed along the first reference line 121, which is advantageous to simplify the manufacturing process of the head tray 111. Further, the lower surfaces of the first mounting groove 114 and the second mounting groove 115 are flush with the lower surfaces of the two rows of print heads 112, respectively, so as to avoid interference influence on the inkjet process of the print heads 112, and thus the lower surfaces of the first mounting groove 114 and the second mounting groove 115 are also combined to form a concave surface, which coincides with the inkjet surface of the print heads 112.

In this embodiment, the printing heads 112 and the mounting grooves are both arranged in two rows and symmetrically arranged with respect to the first reference line 121 of the head tray 111. The single print head 112 has four rows of orifices 113, specifically of the type XAAR2001-GS12C. The printing head 112 is obliquely installed at an angle of deflection phi =2.56 ° with respect to the first reference line 121 of the head tray 111, the radius of the corresponding cambered printing surface is 570mm, the width of the printing head 112 is 50mm, and the installation included angle theta =174.88 ° between the first installation groove 114 and the second installation groove 115. The plurality of print heads 112 are mounted one by one in the first and second mounting

grooves

114 and 115 by fasteners. Furthermore, in other embodiments, the print heads 112 may be arranged in three rows in parallel, with the center line of the print heads 112 in the middle row coinciding with the first reference line 121.

As shown in fig. 9 to 11, optionally, a nozzle cleaning assembly 150 is further included, the nozzle cleaning assembly 150 is mounted on the nozzle tray 111, and the nozzle cleaning assembly 150 includes a negative pressure suction nozzle 151 and a reciprocating drive mechanism 152; the negative pressure suction nozzle 151 abuts against the lower surface of the printing head 112, and the reciprocating driving mechanism 152 drives the negative pressure suction nozzle 151 to reciprocate along the length direction of the head tray 111.

In this embodiment, the negative pressure suction nozzle 151 is located below the head tray 111, and the upper surface of the negative pressure suction nozzle 151 is the same as the ink ejection surface of the print head 112 and contacts with each other. The interior of the negative pressure suction nozzle 151 is communicated with an external negative pressure device, and when the negative pressure device works, the upper surface of the negative pressure suction nozzle 151 has suction force. The reciprocating driving mechanism 152 is installed on the head tray 111, and the reciprocating driving mechanism 152 drives the negative pressure suction nozzle 151 to reciprocate along the length direction of the head tray 111. When the printer is normally used, the negative pressure suction nozzle 151 stays at one end of the nozzle tray 111 in the length direction, and the normal operation of the printing nozzle 112 is not influenced; during cleaning, the reciprocating driving mechanism 152 pushes the negative pressure suction nozzle 151 to sequentially traverse all the print heads 112, and the negative pressure suction nozzle 151 dredges and cleans the nozzle holes 113 of the print heads 112 by suction on the upper surface. The setting of subassembly 150 is washd through the shower nozzle to this scheme, when printing shower nozzle 112 cleanness, just need not print the dismantlement of shower nozzle subassembly, and whole clean process automation goes on, and work efficiency greatly improves.

Example 3

As shown in fig. 12, this embodiment is a roll printing apparatus 100 having a deflection angle. The printing device comprises a roller 130, a linear moving component 140 and the printing nozzle component 110 with a deflection angle in the embodiment 2; the roll 130 is used for winding and conveying a printing medium; the linear moving assembly 140 is used for driving the print head assembly 110 and adjusting the distance between the print head assembly 110 and the surface of the roller 130; the print head assembly 110 is used to inkjet print media.

Preferably, the roller 130 is located below the linear moving assembly 140 and the print head assembly 110, and the vertical center line of the roller 130 is the fourth reference line 124; the four groups of printing nozzle assemblies 110 are sequentially arranged around the roller 130 at intervals from left to right and are symmetrically arranged relative to the fourth reference line 124; three groups of linear moving assemblies 140 are sequentially arranged around the roller 130 at intervals from left to right and are symmetrically arranged relative to the fourth reference line 124; the left printing nozzle assembly 110 is fixedly connected with the left linear moving assembly 140, the right printing nozzle assembly 110 is fixedly connected with the right linear moving assembly 140, and the middle two printing nozzle assemblies 110 are simultaneously and fixedly connected with the middle linear moving assembly 140; each set of linear motion assemblies 140 independently drives the print head assembly 110 to adjust the distance between the print head assembly 110 and the surface of the roll 130.

In the scheme, four groups of printing nozzle assemblies 110 are arranged and respectively correspond to four color divisions (CMYK) of color printing, each group of printing nozzle assemblies 110 is only responsible for painting one color, the number of printing nozzles 112 on the nozzle tray 111 is small (only two rows are required at the lowest), and the processing and manufacturing difficulty of the nozzle tray 111 is reduced. In addition, the left and right print head assemblies 110 are separately driven by the left and right linear movement assemblies 140, so that the movement direction of the print head assembly 110 coincides with the first reference line 121, that is, the included angle α is zero, and the influence of the included angle α on the printing of the print head 112 perpendicular to the surface of the roller 130 is avoided. Secondly, the two middle groups of print head assemblies 110 are driven by the middle linear moving assembly 140 at the same time, so that the number of the linear moving assemblies 140 can be reduced, and the overall size of the printing device can be reduced. Of course, in order to ensure the quality of the inkjet printing of the middle two sets of print head assemblies 110, the angle α between the moving direction of the nozzle holes and the first reference line should be as small as possible. The three groups of linear moving assemblies 140 drive the printing nozzle assembly 110 to move, so that the working height of the printing nozzle assembly 110 during spray painting is adjusted, and the requirements of printing media with different thicknesses and spray painting are met.

In this embodiment, the print head assembly 110 adopts the structure of embodiment 2, and the radius of the corresponding roller 130 is 570mm. The print head assemblies 110 are sequentially wound around the roll 130 at 30 ° intervals. The first reference line 121 of the middle two sets of print head assemblies 110 is at an angle of 15 deg. to the fourth reference line 124 of the roller 130.

In this embodiment, the linear moving assembly 140 includes a servo motor 141 for providing power, a lead screw nut 142, and the like, and a slider 143, a guide rail 144, a connection plate 145, and the like for providing support. The axis of the feed screw nut, i.e., the center line of the linear motion assembly 140, is directed toward the center of the roller 130. Three sets of linearly moving assemblies 140 are sequentially wound around the drum 130 at 45 ° intervals, and the center line of the middle linearly moving assembly 140 coincides with the fourth reference line 124 of the drum 130. Further, the left and right print head assemblies 110 are centrally installed on the lower portions of the connection plates 145 of the left and right linearly moving assemblies 140 by fasteners, respectively, with the first reference line 121 of the head tray 111 coinciding with the center line of the linearly moving assembly 140. The middle two print head assemblies 110 are simultaneously mounted by fasteners to the lower portion of the connecting plate 145 of the middle linear-motion assembly 140 with the first reference line 121 of the head tray 111 at a 15 deg. angle to the centerline of the linear-motion assembly 140.

In this embodiment, the outer surface of the roller 130 is provided with a plurality of air holes, the interior of the roller 130 is communicated with an external negative pressure device, and the roller 130 adsorbs the printing medium to the outer surface thereof through the air holes with negative pressure. The axial end of the roller 130 is connected with a driving device (such as a motor). After the roller 130 conveys the printing medium to a printing area, the air holes on the roller 130 are communicated with negative pressure, so that the printing medium is adsorbed on the outer surface of the roller; the roller 130 conveys the printing medium into or out of the printing area, the air holes on the roller 130 lose the negative pressure, and the printing medium is wound on the surface of the roller by means of the tension of the printing medium. The specific structure of the roller 130 can refer to Chinese patent-202110615060.4-printer roller with negative pressure adsorption.

Preferably, the roll printing apparatus 100 further includes a first heating roller 161, or a first heating roller 161 and a second heating roller 162; the first heating roller 161 is for heating a printing surface of the printing medium; the second heating roller 162 is for heating the back side of the printing medium; the printing medium is sequentially wound around the first heating roller 161 and the drum 130, or the printing medium is sequentially wound around the second heating roller 162, the first heating roller 161, and the drum 130. The printing medium is heated and then is subjected to ink jet printing, so that the ink adhesion and the solvent drying are facilitated, the image-text color quality is improved, and the subsequent drying requirement on the first drying device 300 is reduced. The two sides of the printing medium are heated, so that the phenomenon that the printing medium is folded and deformed due to heating can be avoided.

Optionally, the roll printing apparatus 100 further includes a first UV curing assembly 171 and a second UV curing assembly 172, the first UV curing assembly 171 and the second UV curing assembly 172 are used for curing the ink attached on the surface of the printing medium in multiple times; a plurality of groups of first UV curing assemblies 171 are respectively disposed at one side of the head tray 111 of the plurality of groups of print head assemblies 110; the second UV curing assembly 172 is disposed remotely from the print head assembly 110; the printing medium passes through a plurality of sets of printing head assemblies 110, a plurality of sets of first UV curing assemblies 171, and a plurality of sets of second UV curing assemblies 172 in sequence.

In this scheme, to the UV ink, then need adopt the UV solidification subassembly to solidify it. Where color-separation multi-pass printing is used for ink-jet printing, the print head assemblies 110 are typically arranged in multiple groups, with each group of print head assemblies 110 performing ink-jet printing of one color. When the printing medium passes through the plurality of groups of printing nozzle assemblies 110 in sequence, each time the inkjet printing of one color is completed, the first UV curing assembly 171 performs the pre-curing on the UV ink of the printing medium, so as to prevent the un-dried UV inks of different colors from interfering with each other, which results in unclear pictures and texts. After the printing medium is completely inkjet printed in all colors, the second UV curing assembly 172 performs final complete curing of all UV inks.

Preferably, the roll printing apparatus 100 further includes an ion air bar 180, and the ion air bar 180 is used for removing static electricity on the surface of the printing medium; the print media passes through the ion air bar 180 and the print head assembly 110 in sequence.

Preferably, the roll printing device 100 further comprises a tension roller assembly 190, and the tension roller assembly 190 is used for adjusting the tension of the printing medium entering the roll printing device 100. The tension roller may move up and down to tension or loosen the printing medium wound thereon.

In this embodiment, the input and output ends of the roll printing apparatus 100 are located on the left side, and the printing medium enters from the lower left side with the printing surface facing upward and exits from the lower left side with the printing surface facing downward. The tension roller assembly 190 is located at the leftmost side of the roller drum 130. The first and

second heating rollers

161 and 162 are positioned on the left side of the roller drum 130 and the right side of the tension roller, and the first heating roller 161 is positioned below the second heating roller 162. An ion wind bar 180 is positioned on the left side of the roller 130 above the second heated roller 162. The four sets of first UV curing assemblies 171 are respectively installed at the right side of the head tray 111 of the four sets of printing head assemblies 110, and the first UV curing assemblies 171 are all located above the rollers 130. A second UV curing assembly 172 is mounted to the right side of the roll 130. The second drying device 400 is installed at the lower right of the drum 130.

In this embodiment, the transport trajectory of the print medium is as follows: the printing medium is fed from the left side of the roll 130, and is wound around the tension roller, the second heating roller 162, and the first heating roller 161 in this order, and then is wound around the roll 130. The printing medium sequentially passes through the ion wind bar 180, the four groups of printing nozzle assemblies 110, the four corresponding groups of first UV curing assemblies 171, second UV curing assemblies 172 and second drying devices 400. After reversing around the roller 130, the printing medium exits from below the left side of the roller 130.

It should be understood that the above-mentioned embodiments of the present invention are only examples for clearly illustrating the technical solutions of the present invention, and are not limitations to the specific embodiments of the present invention. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An inkjet printing system with external drying comprises an unreeling device, a roller printing device, a first drying device and a reeling device; the method is characterized in that a printing medium is unfolded by an unwinding device, subjected to ink jet printing by a roller printing device, dried by a first drying device, and finally coiled by a winding device; the unwinding device, the first drying device and the winding device are all located on the same side of the roller printing device, and the printing medium enters and leaves from the same side of the roller printing device.

2. The inkjet printing system with external drying according to claim 1, wherein the unwinding device comprises a first sensor and/or a second sensor, and the winding device comprises a first sensor and/or a second sensor; the first sensor is used for obtaining the thickness of the roll material by measuring the roll surface position of the printing medium; the second sensor is used for obtaining the offset of the roll stock by measuring the edge position of the printing medium.

3. The inkjet printing system with external drying according to claim 1, wherein the first drying device comprises a box body, and a heater, a cross flow fan and a driving roller which are arranged in an inner cavity of the box body; the transverse flow fans and the transmission rollers are arranged up and down oppositely, and the transmission rollers and the transverse flow fans are arranged at intervals along the length direction of the box body; the printing medium sequentially passes through gaps between the driving rollers and the cross flow fans.

4. The inkjet printing system with external drying according to claim 3, wherein the box body comprises a horizontal section and an inclined section in sequence along the conveying direction of the printing medium, the ratio of the length of the inclined section to the length of the horizontal section is not less than 2, and the inclination angle of the inclined section is 25-30 degrees.

5. The inkjet printing system with external drying as claimed in claim 3, wherein the winding device further comprises a guide belt, and the first drying device further comprises a traction mechanism disposed in the inner cavity of the first drying device; and the guide belt is unfolded by the winding device, is clamped by the traction mechanism and is conveyed to the other side of the box body along the reverse direction of the conveying direction of the printing medium, and sequentially passes through gaps between the plurality of driving rollers and the plurality of cross flow fans.

6. The inkjet printing system with the external drying function according to any one of claims 1 to 5, wherein the roller printing device comprises a roller, a linear moving assembly and a printing nozzle assembly; the roller is used for winding and conveying the printing medium; the linear moving assembly is used for driving the printing nozzle assembly and adjusting the distance between the printing nozzle assembly and the surface of the roller; the printing nozzle assembly is used for carrying out ink jet printing on a printing medium;

the printing spray head assembly comprises a spray head tray and printing spray heads arranged on the spray head tray, the printing spray heads are distributed on the spray head tray in a plurality of rows in parallel, and the printing spray heads on two adjacent rows are overlapped in a staggered manner; the printing nozzle is obliquely arranged relative to the nozzle tray; a plurality of rows of printing nozzles are arranged around the surface of the roller, the lower surfaces of the plurality of rows of printing nozzles are combined to form a concave ink jet surface, and each surface of the ink jet surface is tangent to the surface of the roller.

7. The inkjet printing system with external drying as claimed in claim 6, wherein the nozzle tray has a first reference line, the first reference line points to the center of the roller surface; the jet orifice of the printing jet head is provided with a second reference line, and the second reference line points to the ink jetting direction of the jet orifice; an included angle between the first reference line and the second reference line is a deflection angle phi, and the printing spray head is obliquely arranged relative to the first reference line at the deflection angle phi;

the calculation formula of the deflection angle phi is as follows:

l is the distance from the spray hole to the first reference line;

h is the height from the spray head tray to the surface of the roller;

alpha is the included angle between the moving direction of the spray hole and the first reference line;

r is the radius of the roller surface.

8. The inkjet printing system with external drying according to claim 6, wherein the roller printing device further comprises a first heating roller, or a first heating roller and a second heating roller; the first heating roller is used for heating the printing surface of the printing medium; the second heating roller is used for heating the back of the printing medium; the printing medium is sequentially wound around the first heating roller and the roller, or the printing medium is sequentially wound around the second heating roller, the first heating roller and the roller.

9. The inkjet printing system with external drying according to claim 6, wherein the roller printing device further comprises a first UV curing assembly and a second UV curing assembly, and the first UV curing assembly and the second UV curing assembly are used for curing the ink attached to the surface of the printing medium in multiple times; the plurality of groups of first UV curing assemblies are respectively arranged on one side of the nozzle tray of the plurality of groups of printing nozzle assemblies; the second UV curing assembly is arranged far away from the printing spray head assembly; the printing medium sequentially passes through the plurality of groups of printing nozzle assemblies, the plurality of groups of first UV curing assemblies and the second UV curing assemblies.

10. The inkjet printing system with external drying according to claim 6, wherein the roller printing device further comprises an ion air bar for removing static electricity on the surface of the printing medium; the printing medium passes through the ion air bar and the printing spray head component in sequence.