Ink-jet printing method and equipment

Abstract

The invention discloses an ink-jet printing method and equipment, and the equipment comprises a feeding device which is used for placing a printing medium; the printing assembly is used for printing the printing medium; the drying device is used for drying the printed printing medium; the preheating device is used for heating the printing medium before the printing medium enters the printing assembly; and the cooling device is used for cooling the dried printing medium. The printing method comprises a preheating process for avoiding arching or wrinkling caused by temperature shock before printing of a printing medium and a cooling process for avoiding viscosity caused by too high ink temperature after printing. According to the scheme, the problem that arching or wrinkling is caused by too fast heating of the printing medium can be solved, and the problem that the printing medium or the printing effect is damaged due to the fact that adhesion is prone to occurring when the printed printing medium is collected can be solved.

Description

Technical Field

[0001] The present invention relates to the field of printing, and specifically to an inkjet printing method and device. Background Art

[0002] During the process of inkjet printing on PVC films (usually with a thickness of about 70um - 90um in the wood grain industry and usually using solvent inks) and soft film printing media, referring to Figure 1 and 2 As shown, it consists of a feeding device 101, a printing platform 102, a printing device 103, a drying device 104, and a winding device 105. Generally, the following steps are required: Heating of the printing platform: Affected by ink, printing media, regional climate, etc., it is necessary to heat the printing media or the ambient temperature 201 (due to the characteristics of materials and inks, generally the ambient temperature is preferably between 18°C and 28°C) to reach the appropriate printing temperature 202 (usually between 30°C and 35°C) to improve the ink absorption ability and maintain good printing quality; Printing by the printing device: Printing is performed by the printing device. Drying by the drying device: Raise to the drying temperature 203 (50°C, which can be specifically determined according to the printing media material, and the drying wattage per unit area can be 3500W / m 2 ((3500W / 1.800m*0.400mm)*70%) to accelerate the evaporation of the water in the ink and improve the ink absorption effect; Winding by the winding device: Wind and store the printed material.

[0003] Between the drying step and the winding step, the printing media is naturally cooled 204 (at a moving speed of 40m / hour, about 1 - 1.5m cooling distance) affected by the ambient temperature, humidity, winding distance, etc. However, during this process, the following problems often occur: (1) Too fast cooling causes deformation, incorrect size or wrinkling of the printed material; (2) Too fast cooling causes distortion of the winding size and may form wrinkles; (3) Insufficient cooling (factors such as insufficient cooling distance, too high drying temperature or too high ambient temperature, etc.), after winding, the ink will have stickiness with the printing media, resulting in damage to the printing effect or damage to the printing media.

[0004] In addition, in order to quickly reach the appropriate temperature at the printing platform position for the printing media or the ambient temperature, the temperature will change violently during this process, which is also likely to cause problems such as arching and wrinkling of the printing media.

[0005] Therefore, in the existing solutions, there are problems such as the printing medium arching or wrinkling due to the over - rapid heating of the printing medium, and the printing medium wrinkling or not being cooled in time after printing, resulting in the ink being prone to stickiness and affecting the printing effect. In order to eliminate the stickiness of the ink after cooling, it is necessary to lengthen the material receiving path, which also leads to the problem of increased equipment volume. At least one of the above problems needs to be solved at present. Summary of the Invention

[0006] Aiming at the deficiencies of the existing technology, the purpose of the present invention is to provide an ink - jet printing method and device. According to different selected implementation schemes, it can solve the problem of the printing medium arching or wrinkling due to over - rapid heating, and / or can solve the problem of the printing medium being easily stuck and damaged or the printing effect being affected when receiving the printed printing medium.

[0007] To achieve the above purpose, the present invention provides the following technical solutions: An ink - jet printing device, comprising: a feeding device for placing a printing medium; a printing component for printing on the printing medium; a drying device for drying the printed printing medium; characterized in that it further comprises: a pre - heating device for heating the printing medium before it enters the printing component; and / or a cooling device for cooling the dried printing medium.

[0008] As a further improvement of the present invention, it further comprises a material receiving device for stacking or winding the printed printing medium.

[0009] As a further improvement of the present invention, when the ink - jet printing device includes the pre - heating device, the pre - heating device is a heating device with an adjustable heating gradient for gradually or step - by - step heating the printing medium.

[0010] As a further improvement of the present invention, when the ink - jet printing device includes the pre - heating device, the pre - heating device is a roller capable of providing heating, and the printing medium contacts the roller.

[0011] As a further improvement of the present invention, the pre - heating device is a roller for providing gradual heating for gradually heating the printing medium.

[0012] As a further improvement of the present invention, the position where the pre - heating device contacts the printing medium gradually or step - by - step increases in temperature from the path corresponding to the feeding device towards the path of the printing component.

[0013] As a further improvement of the present invention, the pre - heating device includes a heating device and a roller, and the heating device and the roller cooperate with each other to pre - adjust the temperature of the printing medium.

[0014] As a further improvement of the present invention, the heating device can adjust the heating rate, and / or the roller can provide heating to the printing medium.

[0015] As a further improvement of the present invention, the position where the heating device and / or the roller contacts the printing medium gradually or stepwise increases in temperature from the path of the corresponding feeding device towards the path of the printing assembly.

[0016] As a further improvement of the present invention, when the inkjet printing device includes the cooling device, the cooling device is an air-cooling device or a water-cooling device.

[0017] As a further improvement of the present invention, the cooling device includes an air-cooling device and a water-cooling device, and the air-cooling device and the water-cooling device cooperate with each other to cool the printing medium.

[0018] As a further improvement of the present invention, the air-cooling device is used to control the cooling rate of the printing medium, and the water-cooling device is used to control the temperature of the printing medium when it is being collected.

[0019] As a further improvement of the present invention, the air-cooling device controls the cooling rate of the printing medium to be a gradual cooling or a stepwise cooling.

[0020] As a further improvement of the present invention, the air-cooling device is used to cool the printing surface of the printing medium, and the water-cooling device is used to cool the printing medium; and / or the air-cooling device is used to cool the printing surface of the printing medium, and the water-cooling device is used to cool the printing medium and the printing surface.

[0021] An inkjet printing method includes a preheating process to avoid arching or wrinkling caused by sudden temperature changes before printing on the printing medium; and / or a first cooling process to avoid sudden temperature drops of the printing medium after printing; and / or a second cooling process to avoid excessive viscosity of the ink due to high temperature after printing.

[0022] As a further improvement of the present invention, the preheating process uses a gradual or stepwise preheating and preheats to the printing temperature required for the printing medium.

[0023] As a further improvement of the present invention, the second cooling process reduces the temperature of the printing medium to at least a temperature at which the ink is not sticky.

[0024] As a further improvement of the present invention, it further includes a drying process for drying the printing medium and / or the ink before the first cooling process, and this drying process increases the temperature of the printing medium and / or the ink.

[0025] As a further improvement of the present invention, the first cooling process performs a gradual cooling or a stepwise cooling on the printed printing medium.

[0026] As a further improvement of the present invention, during printing, the printing platform maintains the temperature of the printing medium after preheating.

[0027] Advantages of the present invention: By preheating the printing medium, problems such as arching or wrinkling caused by sudden temperature changes during printing are avoided; by cooling the printed printing medium, the ink is prevented from being damaged due to insufficient cooling and resulting in stickiness. The above preheating process and cooling process can be applied simultaneously to provide a better cooperation effect, or one of the schemes can be selected for application to produce the desired effect. Description of the Drawings

[0028] Figure 1 It is a schematic diagram of a device module in the prior art; Figure 2 It is a temperature change diagram in the prior art; Figure 3 It is a schematic diagram of a scheme module of the present invention with a preheating device and a cooling device; Figure 4 It is a stepped temperature change diagram of the present invention; Figure 5 It is a progressive temperature change diagram of the present invention; Figure 6 It is a schematic diagram of one implementation manner of the cooling device of the present invention; Figure 7 It is a schematic diagram of another implementation manner of the cooling device of the present invention. Detailed Embodiments

[0029] The present invention will be further described in detail below with reference to the embodiments given in the drawings.

[0030] Refer to Figure 3 、 4 、5 shown, An inkjet printing device includes A feeding device 301 for placing a printing medium; A printing assembly 302 for printing on the printing medium; A drying device 303 for drying the printed printing medium; A preheating device 304 for heating the printing medium before the printing medium enters the printing assembly; and / or A cooling device 305 for cooling the printed printing medium.

[0031] In the present solution, one of the preheating device and the cooling device can be selected for application, or both can be provided to produce a better application effect.

[0032] General printing media need to meet appropriate printing temperatures at the position of the printing component. At this time, rapid heating is required. Under the action of this rapid heating, the printing media are prone to arching and wrinkling, especially when the printing media are made of paper and flexible films.

[0033] In addition, after printing, drying is required. Since drying further heats up, the moisture of the ink volatilizes faster. At this time, the temperature of the printing media will further increase. After drying, the printing media need to be collected. The printing media generally have a certain travel distance from the drying device to the collection position. At present, the cooling process of the printing media after drying is mainly natural cooling during this travel. The cooling speed of natural cooling is limited, and it is easy for the printing media not to be completely cooled when they reach the collection position. At this time, the ink still has a certain viscosity, making the printing media prone to sticking when stacked or wound. At this time, it is easy to damage the printing media and the printing effect.

[0034] In this solution, after the printing media are output from the feeding device 301, they are first heated to a preset temperature 401 (such as 30 - 35 °C) by the preheating device 304. This preset temperature 401 can directly meet the temperature required for printing, or it can be a temperature that has not yet met the printing requirements (as Figure 5 shown), but it can be further heated and raised in temperature by the printing component 302. Since this is a preheating process, there is no need to rapidly raise the temperature to meet the printing requirements. Therefore, it is possible to eliminate the arching and wrinkling of the material due to rapid temperature rise at the position of the printing component 305, ensuring a flat surface during printing. The heated printing media enter the printing component 302 to complete inkjet printing, and then reach the drying temperature 402 (50 °C - 60 °C, preferably 50 °C - 55 °C. When the printing media is thinner, such as 70 μm, the heating temperature is set at a lower temperature of 50 °C) through the drying device 303 (such as an infrared heater or an electric wire heating and blowing device, etc.) to rapidly cure the ink (in this way, the length of movement of the printing media in the printing device can be shortened). The dried printing media are cooled by the cooling device 305 (such as an air-cooling fan or a water-cooling pipe) until the ink is no longer sticky. The cooling temperature 403 is usually the ambient temperature, which is about 18 °C - 28 °C with reference to the material characteristics of the printing media, to avoid the remaining heat causing the ink to stick. The temperature of the cooling temperature 403 can be selected to be slightly lower (with reference to Figure 4The part within the hatching lines is at a relatively low temperature, slightly lower than room temperature, such as 16°C). At the same time, in order to prevent the printing medium from undergoing excessive shrinkage and forming dimensional deformation due to too rapid cooling during the cooling process, or uneven shrinkage and forming wrinkles, the cooling process must be controlled at an appropriate cooling gradient (taking natural cooling as an example, the cooling distance is about 1 - 1.5 m @ a printing medium moving speed of 40 m / hour. For better control of the cooling gradient, further explanations will be provided later). The synergistic effect of preheating and cooling significantly improves the smoothness and durability of the printed product, and can enhance the quality of inkjet printing. Figure 4 The dashed line part in it is the temperature change in the prior art.

[0035] The above-mentioned preheating device 304 and cooling device 305 can also be selected and implemented separately, or both can be implemented simultaneously.

[0036] In an optional solution, a receiving device 306 can also be additionally provided for stacking or winding the printed printing medium.

[0037] The cooled printing medium is automatically wound by an electric roller, or a reciprocating finishing device can also be used to stack the printing medium.

[0038] Among them, the feeding device 301 can also be a roller, for example, a roller without power. The rolled printing medium is coaxially placed on this roller and can automatically feed as the receiving device pulls during the receiving process. The feeding device 301 can have a certain damping, which can form a tension cooperation with the receiving device, making the printing effect of the printing medium more stable under the action of tension. And this structure for providing tension is simple and can also improve production efficiency.

[0039] Specifically, when the inkjet printing device includes a preheating device 304, the preheating device 304 is a heating device 3041 with an adjustable heating gradient for gradually heating or stepwise heating the printing medium.

[0040] As an adjustable heating gradient, the preheating device 304 can refer to Figure 4 the temperature gradient diagram in the preheating stage shown, and can adjust the heating speed of the printing medium to make the heating more stable and gentle, avoiding rapid heating at the position of the printing component.

[0041] On the basis of this solution, the platform 3021 of the printing component 302 can be only used to maintain the temperature required for printing, without the need to additionally heat the printing medium.

[0042] The preheating device 304 can adopt a resistance wire heater or an infrared heater, which can adjust the heating power and has a certain heating stroke. At this time, when the printing medium passes through this heating stroke, it will be gradually heated. By adjusting the heating power, the temperature of the printing medium when it passes through this heating stroke at a constant speed and leaves the preheating device 304 can be adjusted. In the implementation of this solution, it can be preferably that the temperature of the printing medium after leaving the preheating device 304 is the required printing temperature 401 for printing, and the printing component 302 cooperates to maintain this temperature. Of course, the temperature will fluctuate during the actual control process, and it still belongs to the category of maintaining this temperature within a certain range of fluctuations. For example, the temperature fluctuates within the range of ±1°C.

[0043] In specific applications, the preheating device 304 can be a roller 3042 that can be heated, which is used to gradually heat the printing medium. And this heatable roller 3042 provides progressive heating, and this progressive heating refers to Figure 5 the temperature gradient diagram of the preheating stage shown in. The process of this temperature heating can express the meaning of progressive heating. In this solution, the heatable roller 3042 can assist in tensioning the printing medium, and can also change the transmission path of the printing medium, and can play different roles in different applicable environments. The printing medium is transmitted closely against the roller surface, and an electric heating wire is arranged inside the roller 3042 to provide a heating effect.

[0044] This progressive temperature can gradually heat up the printing medium by the way of the heating stroke as described above. For example, the heating temperature remains unchanged, and the heating duration brought by the heating stroke is used for heating. It can also be implemented by the following solution. The position of the preheating device 304 corresponding to the printing medium gradually becomes higher or stepwise higher in temperature from the path of the corresponding feeding device towards the path of the printing component.

[0045] This path is the path for the printing medium to move towards the printing component. In this solution, under this path, the temperature of the preheating device 304 will gradually increase, thereby forming progressive or stepwise heating of the printing medium. Progressive means a more continuous and smooth heating shown in the figure, while stepwise means that there are certain temperature levels (which can be as Figure 4 shown). For example, there is a deviation of 1°C between 20°C and 21°C, and this deviation will form a step, while progressive means a smaller deviation level, such as 0.1°C. At this time, it is close to a continuous and smooth heating state. In an ideal state, there is no deviation level, but a continuous heating state.

[0046] The above-mentioned preheating device 304 can adopt a heating device 3041 or a roller 3042, but the two can also be used in combination at the same time. The preheating device 304 includes a heating device 3041 and a roller 3042, and the heating device 3041 and the roller 3042 cooperate with each other to pre-adjust the temperature of the printing medium.

[0047] In some scenarios, it is necessary to use the roller 3042 to adjust the conveying direction or tension of the printing medium. At this time, the roller 3042 can also provide a heating function and cooperate with the heating device 3041 for heating. The two cooperate with each other to heat and further stabilize the temperature of the printing medium, avoiding the problem that the temperature of the printing medium drops after passing through the roller and further temperature adjustment is required at the position of the printing assembly 302. The roller 3042 in this solution can also function as stabilizing the temperature or cooling. For example, the printing material can be naturally cooled after passing through the roller and then enter the printing assembly 302 for further heating. Different application environments are required for different printing media, but this application method cannot be excluded.

[0048] Based on the above solution in which the heating device 3041 and the roller 3042 are applied simultaneously, the heating device 3041 can adjust the heating gradient, and the roller 3042 can provide heating to the printing medium.

[0049] Among them, the positions where the heating device 3041 and / or the roller 3042 contact the printing medium gradually increase or stepwise increase in temperature along the path of the corresponding feeding device 301 towards the path of the printing assembly.

[0050] As an implementation of the cooling device 305, refer to Figure 6 As shown in, the cooling device 305 is an air-cooling device 3051 or a water-cooling device 3052. The air-cooling device 3051 can use a fan in combination with a refrigeration component or a heat-conducting component, or simply a fan to blow air flow to drive the cooling of the printing medium. The water-cooling device 3052 can be a device with a water pump, a water pipe, and a cooler in cooperation, which can drive the water circulation in the water pipe through the water pump, use this water circulation to take away the temperature of the printing medium, and cooperate with the cooler for cooling and then repeat the circulation action. The cooler can be a fan or a refrigeration component.

[0051] Of course, the cooling device 305 can also be an application method that simultaneously has an air-cooling device 3051 and a water-cooling device 3052. The dual-mode cooling method can make the cooling speed faster, shorten the material receiving stroke, and the dual-mode cooling can also make the medium cool evenly as a whole, avoiding the curling problem caused by unilateral cooling. When the cooling device 305 cools, it can adopt progressive cooling or stepped cooling, and control the cooling speed through this progressive or stepped cooling, avoiding uneven cooling speed and the change in the size of the printing medium caused by too fast cooling.

[0052] During the application process, refer to Figure 6 As shown in, the air-cooling device 3051 is used to cool the printing surface of the printing medium, and the water-cooling device 3052 is used to cool the printing medium; and / or, Refer to Figure 7As shown, the air-cooling device 3051 is used to cool the printing surface of the printing medium, and the water-cooling device 3052 is used to cool the printing medium and the printing surface.

[0053] The air-cooling device 3051 cooling the printing surface can further remove the moisture of the ink, accelerate the drying of the ink, and the combined cooling can make the ink lose its viscosity. Of course, the water-cooling device 3052 can also cool the printing surface in a non-contact manner.

[0054] Referring to Figure 4 and 5 the temperature change in

[0055] In the foregoing embodiments, the printing assembly is composed of components such as a printing platform, a print head, a heater, etc., which belong to the existing printing assembly and will not be elaborated here.

[0056] The foregoing introduced an inkjet printing device. Based on this innovative concept, the following also provides an inkjet printing method, including a preheating process to avoid arching or wrinkling caused by sudden temperature changes before printing on the printing medium; and / or a first cooling process to avoid sudden temperature drop of the printing medium after printing; and / or a second cooling process to avoid excessive ink temperature and resulting viscosity after printing.

[0057] The preheating process uses progressive or stepped preheating and preheats to the printing temperature required for the printing medium.

[0058] The second cooling process reduces the temperature of the printing medium to at least the temperature at which the ink is not sticky. The temperature at which the ink is not sticky varies depending on the specific ink material and is usually the ambient temperature, which is about 18°C to 28°C with reference to the material characteristics of the printing medium.

[0059] It also includes a drying process for drying the printing medium and / or the ink before the first cooling process, and this drying process raises the temperature of the printing medium and / or the ink.

[0060] The first cooling process performs progressive cooling or stepped cooling on the printed printing medium.

[0061] During printing, the printing platform maintains the temperature of the printing medium after preheating.

[0062] The above are only the preferred embodiments of the present invention. The protection scope of the present invention is not limited to the above embodiments. All technical solutions falling within the concept of the present invention belong to the protection scope of the present invention. It should be noted that for those of ordinary skill in the art, several improvements and refinements made without departing from the principle of the present invention should also be regarded as within the protection scope of the present invention.

Claims

1. An inkjet printing device, comprising a feeding device for placing a printing medium; a printing assembly for printing on the printing medium; a drying device for drying the printed printing medium; characterized in that it further comprises a preheating device for heating the printing medium before the printing medium enters the printing assembly; and / or a cooling device for cooling the dried printing medium.

2. The inkjet printing device according to claim 1, characterized in that, It further comprises a receiving device for stacking or winding the printed printing medium.

3. The inkjet printing device according to claim 1, characterized in that, When the inkjet printing device comprises the preheating device, the preheating device is a heating device with an adjustable heating gradient, and is used for gradually heating or stepwise heating the printing medium.

4. The inkjet printing device according to claim 1, characterized in that, When the inkjet printing device comprises the preheating device, the preheating device is a roller capable of providing heating, and the printing medium contacts the roller.

5. The inkjet printing device according to claim 4, wherein The preheating device is a roller for providing progressive heating, and is used for gradually heating the printing medium.

6. The inkjet printing device according to claim 3 or 5, characterized in that, The position of the preheating device corresponding to the printing medium has a gradually increasing or stepwise increasing temperature from the path of the corresponding feeding device towards the path of the printing assembly.

7. The inkjet printing device according to claim 1, characterized in that, The preheating device comprises a heating device and a roller, and the heating device and the roller cooperate with each other to pre-adjust the temperature of the printing medium.

8. The inkjet printing device according to claim 7, characterized in that the heating device can adjust the heating gradient, and / or the roller can provide heating to the printing medium.

9. The inkjet printing apparatus according to claim 8, wherein, The position where the heating device and / or the roller contacts the printing medium has a gradually increasing or stepwise increasing temperature from the path of the corresponding feeding device towards the path of the printing assembly.

10. The inkjet printing device according to claim 1, wherein When the inkjet printing device comprises the cooling device, the cooling device is an air cooling device or a water cooling device.

11. The inkjet printing device according to claim 1, characterized in that, When the inkjet printing device comprises the cooling device, the cooling device comprises an air cooling device and a water cooling device, and the air cooling device and the water cooling device cooperate with each other to cool the printing medium.

12. The inkjet printing device according to claim 11, wherein The air cooling device is used to control the cooling gradient of the printing medium, and the water cooling device is used to control the temperature of the printing medium during receiving.

13. The inkjet printing device according to claim 12, characterized in that, The air cooling device controls the cooling gradient of the printing medium to be progressive cooling or stepwise cooling.

14. The inkjet printing device according to claim 1, characterized in that, When the inkjet printing device comprises the cooling device, the cooling device performs progressive cooling or stepwise cooling on the printing medium.

15. The inkjet printing device according to claim 11, characterized in that the air cooling device is used to cool the printing surface of the printing medium, and the water cooling device is used to cool the printing medium; and / or, the air cooling device is used to cool the printing surface of the printing medium, and the water cooling device is used to cool the printing medium and the printing surface.

16. An inkjet printing method, characterized in that, It includes a preheating process to avoid arching or wrinkling caused by sudden temperature change before printing on the printing medium; and / or a first cooling process to avoid sudden temperature drop of the printing medium after printing; and / or a second cooling process to avoid excessive viscosity of the ink due to too high temperature of the ink after printing.

17. The inkjet printing method according to claim 16, wherein The preheating process adopts progressive or stepwise preheating and preheats to the printing temperature required by the printing medium.

18. The inkjet printing method according to claim 16 or 17, characterized in that, The second cooling process reduces the temperature of the printing medium to at least the temperature at which the ink is not sticky.

19. The inkjet printing method according to claim 16, wherein It further includes a drying process for drying the printing medium and / or the ink before the first cooling process, and this drying process increases the temperature of the printing medium and / or the ink.

20. The inkjet printing method according to claim 16, wherein The first cooling process performs progressive cooling or stepwise cooling on the printed printing medium.

21. The inkjet printing method according to claim 16 or 17 or 19 or 20, characterized in that, During printing, the printing platform maintains the temperature of the printing medium after preheating.

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