ES2900498T3 - Printing platform for inkjet printing equipment - Google Patents

Abstract

Printing platform structure comprising a printing platform (1) located between a paper feeding platform and a paper output platform, where there are several convex planes (2) and concave planes (3) formed on one side that is in contact with the printing medium, where the convex planes (2) and the concave planes (3) are alternately along the X direction of the printing platform, and extend along the Y direction of the printing platform. printing platform; where the paper exit ends of the concave planes (3) are free of any bulging structure, characterized by the fact that on the printing platform (1) there are several air suction holes (11) located in the concave planes (3); and the height difference H between the convex planes (2) and the concave planes (3) is greater than or equal to ΔE/(2N), ΔE is the length increased after the medium absorbs the ink, and N is the amount of the convex planes on the printing platform.

Description

DESCRIPTION

Printing platform for inkjet printing equipment

field of invention

technical field

[0001] The present invention relates to the field of printers, and in particular to a medium support inkjet printing platform for inkjet printing equipment.

Antecedent technique

[0002] As the main equipment for digital printing, printers are used more and more widely. Inkjet printing, as the main printing equipment, can do inkjet printing on various different media, such as various types of paper, polymer film media and films, various types of cloth, etc, and it is playing a increasingly important role. Color inkjet has relatively high requirements on color reproduction, therefore, for general printing media, a coating or treatment agent is formed on the surface of base material to control the diffusion of inks. ink droplets and absorb the ink. In the case of paper with plant fiber base material or other water-absorbent media, after ink jetting, the base material swells and deforms by absorbing ink, and local bulging occurs on the printing platform , affecting the print accuracy effect in less severe cases and scratching the print head in more severe cases, causing damage to expensive sprayers or abandonment of batch printed products. This problem has increasingly affected the normal operation of printers, especially in the field of production application, for example the printing of decorative images in the digital textile printing industry, which requires a particularly high level of operational stability. Since the accuracy of the effective distance between the print head and the bed has an obvious influence on the printing effect, traditional machine designs try to ensure the flatness of the print bed and minimize the distance between the sprayer and the printing platform, as well as to guarantee the parallelism of movement between the printing platform and the inkjet printing carriage. Therefore, the print platforms are all flat, especially on productive large-format printing equipment. However, in order to effectively control the problem of bulging and deformation of the medium on the platform after absorbing the jet printing liquid, for the design of the conventional printing platform, it is necessary to provide some air suction structures while flatness is ensured, in order to allow the media to be adhered to the platform, typically including the following three ways:

1. Air suction holes of certain density are distributed on the platform, and low-pressure adsorption is generated through the fan under the platform, as shown in Figure 1 and Figure 2.

2. Some air suction holes are distributed on the platform, and they combine with the groove design to enlarge the air suction area. Depending on the material selected for the deck, two types of slot design can be used:

(1) In the case of plastic injection mold platform or metal casting mold platform, generally some intersecting or oblique intersecting grooves can be flexibly adopted, so as to enlarge the air suction area and increase the air suction uniformity, as shown in Figure 3.

(2) In the case of extruded profile decks, such as decks processed using aluminum alloy extruded raw material, transverse grooves may be distributed along the extrusion length direction.

3. Some companies may also distribute some air suction holes on the deck, and enlarge the area around these holes to form some shallow air suction cavities to enlarge the air suction area . But such structures generally concentrate on air suction effect enhancement design, so that the outer circles of the cavities are flush with the printing platform, in order to ensure that the height of the paper is not affected. Basically, as shown in Figure 4.

[0003] Defects of the existing technique: The base material swells after the water-absorbent medium absorbs the ink, due to the combined action of the winding tension of a feed roller in the directions of pushing and taking up the paper in the media, the media generates irregular vertical bowing and bulging in the paper feed direction (Y direction), which affects the print image quality. When the local bulge height is too large, the print head may be scratched and cause image deterioration. The wrinkling and bulging conditions in actual operation are shown in Figure 5 and Figure 6, and both the wrinkling position and height have uncertainty. US-B-6270215 discloses the preamble of claim 1.

Summary of the invention

[0004] In order to solve the drawbacks of the existing art, the present invention provides a printing platform structure that can evenly absorb the bulge of the medium and remarkably eliminate the upward bowing of the medium, so as to completely prevent wear. of a print head caused by medium bulge and improve the image quality and printing effect.

[0005] The present invention provides a printing platform, said platform is located between a paper feed platform and a paper output platform, there are several convex and concave planes formed on one side of the printing platform that is in contact with the printing medium, the convex planes and the concave planes alternately lie along the X direction of the printing platform, and extend along the Y direction of the printing platform; and the paper exit end of the concave planes is free of any bulging structure (There is no preset structure that comes close to the height of the convex planes). On the printing platform there are air suction holes located on the concave planes. The height difference H between the convex planes and the concave planes is greater than or equal to AE/(2N), AE is the length increased after the medium absorbs the ink, and N is the amount of the convex planes on the platform of impression.

[0006] Preferably, several air suction holes are provided on the printing platform located on the convex planes.

[0007] More preferably, the height difference H between the convex and concave planes is greater than or equal to 0.1 mm and less than or equal to 0.8 mm; and the horizontal width of the concave planes is greater than 0.4 mm.

[0008] Preferably, the concave planes at the paper feed end are closed, and the width of the concave planes gradually increases along the direction of paper exit from the printing platform.

[0009] Preferably, a convex plane a with relatively small length is set on the printing platform, said convex plane a starts from the paper feeding end, and the convex plane a and the convex planes of the printing platform are alternately distributed. .

[0010] Preferably, in the convex and concave planes of the printing platform there are several slots or other auxiliary air suction structure.

[0011] Preferably, the height of the highest part of the paper output platform is less than the height of the convex planes of the printing platform or less than the height of the concave planes.

[0012] Preferably, the guide sections B and C are additionally arranged between the paper feed platform and the printing platform, while the guide section E is additionally arranged between the paper output platform and the printing platform. , the height of the highest point of sections B, C and E is less than the height of the concave planes of the printing platform.

[0013] Preferably, the printing platforms can be joined to each other.

[0014] The Printing Platform (or Jet Printing Platform”, Main Printing Platform) described in the present invention refers to the partial width platform corresponding to the width (Y direction) of the print head, that is, the platform corresponding to the real-time ink jet of the print head during the operation of the printer. In the industry it is also called the main printing platform. In the printer structure, there is usually an auxiliary paper feed bed at the front end (near the feed roller) of the printing bed; and an auxiliary paper output platform at the rear end (near the winding part) of the printing platform.

[0015] All the convex planes extend in the width (Y-direction) of the entire platform in the longitudinal direction, and all the concave planes also extend in the width (Y-direction) of the entire platform in the longitudinal direction.

[0016] In the concave planes there should be no ribs or other horizontal structures (X direction) that have the same height as the convex planes, which affects the general effect of concave absorption and the effect of longitudinal movement of the medium. If the reinforcement of the air suction effect is considered, the planned rib structure should be lower than the convex planes. Multi-pass overlapping is generally adopted for ink jetting, the amount of ink is gradually increased as it approaches the trailing end (paper trailing end), so there should be no bulge at the trailing end of the paper of the concave planes, while the amount of ink at the leading end (near the trailing end) paper feed) is relatively small, structures such as ribs can be arranged properly, and can be flush with the convex planes at most. The paper exit end of the concave planes is at full length, there is no bulge structure, and it is combined with the integral sinking design of the auxiliary paper exit platform at the rear end (being lower than the convex planes, or not being higher than the concave planes), which is the key point of the present invention. This is the fundamental difference of the present invention from other manufacturers in the principle of printing medium bulge design and processing.

[0017] All the concave planes should have a sufficient width to be favorable for the sinking of the medium with the help of air suction, and absorb the swelling amount of the medium. In general, the horizontal width of each concave plane should be greater than 5mm. And the specific horizontal width should be reasonably calculated, estimated and tested according to the stiffness of the medium and the air suction force as well as the winding tension.

[0018] The difference in height between the convex and concave planes is relatively small. For the print head with low ink droplet flight speed and small ink droplets, the height difference is generally between 0.1mm and 0.8mm. While in the case of the print head with high ink drop flying speed and large ink drop, the height difference can suitably be larger, and is generally not more than 4mm at most.

[0019] A relatively large integral amount of swelling absorption is achieved by evenly distributing sufficient convex and concave planes throughout the platform. The height difference between convex planes and concave planes is minimized under the condition that the integral amount of absorption reaches the requirements of use, in order to ensure that the printing effect is not affected.

[0020] The arrangement of the air suction holes or other air suction structure is concentrated in the area of the concave planes. A certain number of air suction holes are also distributed in the convex planes, or they may not be distributed in the convex planes.

[0021] The platform is more suitable for the manufacture of plastic molds or the segmented production of metal casting molds. Machining mode can also be adopted, but the manufacturing cost is relatively high. Other auxiliary means such as gluing method can also be adopted to make the convex planes.

[0022] The height of the highest part of the paper output platform at the rear end should be less than the height of the convex planes, and at least close to the height of the concave planes.

[0023] There may also be an empty section in the paper exit platform at the rear end, which is favorable for the free dispersion of the arcuate part in the middle.

[0024] Analysis of structure and forms of application of the design:

1. In a normal state, the medium will swell after absorbing ink. For a section of media with a normal length L, the length increased after water absorption is AE, as shown in Figure 8. The size of AE depends on several factors, such as the characteristics of the base material of the media and coating, amount of printing ink, printing speed and duration time, but generally can be obtained by testing under actual working conditions.

2. Various work platforms on the market may exhibit irregular local bowing under the combined action of various factors, such as the friction force of the medium, the winding tension of the paper, the air suction force, and the distribution of the amount of image ink, as shown in Figure 8, Figure 5 and Figure 6. The characteristics are that the heights of the arcs are different and unpredictable, and special local protrusions may occur.

[0025] The structure design of the new printing platform is shown in Figure 9. The convex and concave parts of the platform are distributed horizontally and evenly on the platform according to the widths of A and B. The height of the convex parts is H. The size of A and B should be integrally determined according to the factors such as the thickness rigidity of the medium, the coating water absorption characteristic of the medium, the air suction force and the tensile stress. paper rolling. And they can be obtained by testing under the actual working conditions. In general, A can be relatively small. While B must have sufficient capacity to overcome the stiffness of the medium, and allow the medium to concave smoothly under the combined action of suction force and winding tension. The size of H can be calculated according to the number N of convex parts and the total AE in the total width of the platform:

H^AE/ (2N)

[0026] Under the condition of meeting the AE absorption condition, e1H should be minimized so that the printing effect is not affected. The effect of the design program is shown in Figure 10, AE is digested and absorbed by a plurality of uniformly distributed convex and concave quantities. In the actual test, After obtaining the proper H value, even in a more severe sensitive color, such as gradient and neutral gray color transition image, the platform has no visible influence on the printing effect. Therefore, the present patent has a high feasibility. Figure 11 is the actual measurement result of the impression after the application of the platform principle, and it can be seen that it is no longer in the uncontrollable bulging state as in Figure 5 and Figure 6. The middle in Figure 11 it may already be fully adhered to the surface of the printing platform, and there are no abnormal parts especially protruding. In this state, the print quality can be greatly improved, and the print head wear problem is solved, so that the equipment can work stably for a long time under difficult working conditions.

[0027] The principle of the present invention is based on absorbing the bulge and deformation of the medium in situ, and therefore, the concave planes at the exit end of the paper in the Y direction are designed with openings, which It is the key point of distinction. That is, there are no other bulging structures at the outlet end of the concave planes, and meanwhile, it is combined with the additional sinking design of the paper outlet platform, so that the swelling amount of the medium sinks from enough way to approach the concave planes, in order to be accommodated and absorbed.

[0028] Based on theory and tests, the invention has reconstructed the platform in an innovative way to control the medium bulge problem without affecting the overall printing accuracy, thus ensuring the long-term stable operation of the printing equipment. jet printing in various amounts of ink and water-absorbent media. The design and production of the product described by the present invention have already been carried out, and they have been used for customers in the industry in batches, and a remarkable effect has been obtained.

[0029] Why can't conventional platform structures solve the bulging problem? This is because the previous thought in the industry is that the medium is flattened by external force or adsorbed by strong air suction. However, the uniform stress conduction is affected by the possibility of non-uniform distribution of modules in the printing area and the stiffness of the medium, and the effect cannot be resolved. Also, the strong adsorption is incompatible with the transfer of the medium, meanwhile the stiffness of the medium and the uncertain area characteristic of the ink jet make the adsorption effect unsatisfactory. And fundamentally, if an entire platform does not have a longitudinal structure that can accommodate and absorb the extra dimension, the problem of AE dimension increase in the bulge of the middle cannot be essentially solved, and in the end AE can only wrinkle up several times. unmeasurable heights, resulting in printhead wear and image damage, as shown in Figure 8, Figure 5, and Figure 6.

[0030] Favorable Effects of the Present Invention: The present invention well solves the problem of ink jet printing medium bulging, which has troubled the industry for a long time, especially in the case of large-format printing equipment with lots of ink. Through the innovative non-planar convex-concave design of the platform, the present invention suitably relies on the absorption of bulge and deformation of the medium in situ. While for the problem that the printing effect is affected because the platform is uneven, which troubles the industry originally, since the ink drops fly down vertically, in a certain stroke, the problem can be ignored. little height difference. The actual test also shows that the printing effect is better than the original design. Precisely because of the small difference in height H, this problem is perfectly solved by the digestion of large AE through multiple distribution and accumulation sections.

Description of the drawings

[0031] Figure 1 is a three-dimensional effect diagram of the printing platform of conventional printing equipment.

Figure 2 is a three-dimensional line diagram of the printing platform of conventional printing equipment.

Figure 3 is a slot design printing equipment platform on the market.

Figure 4 is a platform of air suction cavity printing equipment on the market. Figure 5 is an image of actual measurement of bulging and wrinkling of a print bed. Figure 6 is an actual measurement image of bulge and wrinkle of another printing platform. Figure 7 is a three-dimensional effect diagram of a platform with the conception of the present invention.

Figure 8 is a schematic diagram of the analysis of the bulge and wrinkle section of the printing platform in the market.

Figure 9 is a schematic diagram of the structure principle of the platform of the present invention. Figure 10 is a schematic diagram of effect analysis of the platform structure of the present invention.

Figure 11 is an actual application test image of the present invention.

Figure 12 is a three-dimensional design program of the front and rear auxiliary platforms. coupled according to the present invention (example 1).

Figure 13 is a note of the key points and operating status of the front and rear auxiliary platforms coupled according to the present invention (case 1).

Figure 14 is an advanced design of the present invention (case 2).

Figure 15 is a schematic diagram of case 3 of the present invention.

Figure 16 is a schematic diagram of case 4 of the present invention.

Figure 17 is a schematic diagram of case 5 of the present invention.

Figure 18 is a schematic diagram of case 6 of the present invention.

Figure 19 is a schematic diagram of case 7 of the present invention.

Figure 20 is a schematic diagram of case 8 of the present invention.

[0032] In the drawings: a-air suction hole, b-spray ink carriage, c-pressure feed roller, d-printing platform, e-paper output platform, f-suction hole air slot and air suction slot, f'-air suction auxiliary cavity, 1-printing platform, 2-convex plane, 3-concave plane, 11-air suction hole, 12-slot

Detailed description of the invention

[0033] A more detailed description of the present invention is given below in conjunction with the attached drawings:

Figures 1 to 6 show the conditions of the printers of the existing art. Figure 1 is a three-dimensional effect diagram of the printing platform of conventional printing equipment. Figure 2 is a three-dimensional line diagram of the printing platform of conventional printing equipment. Figure 3 is a slot design printing equipment platform on the market. Figure 4 is a platform of air suction cavity printing equipment on the market. Figure 5 is an image of actual measurement of bulging and wrinkling of a print bed. Figure 6 is an actual measurement image of bulge and wrinkle of another printing platform.

[0034] A printing bed structure includes vertical convex planes with a certain width, which are evenly distributed along the X direction (ie, the printing width direction) of the entire bed; meanwhile, concave planes with certain width are presented which are combined with convex planes alternately. In addition, more air suction holes are distributed in the concave planes, and a certain number of air suction holes are distributed in the convex planes or not in the convex planes, as shown in Figure 7.

[0035] A schematic diagram of the structure of the present invention is shown in Figure 7 . The printing platform structure provided by this invention includes a printing platform located between a paper feeding platform and a paper output platform, there are several convex 2 and concave 3 planes formed on one side of said printing platform 1 which is in contact with the printing medium, the convex planes 2 and the concave planes 3 alternately lie along the length of the printing platform 1, and extend along the Y direction (along the printing platform paper exit direction) of the printing platform 1. The concave planes 3 are provided in an open way, that is, the exit end of the concave planes is free from any other bulging structure. On the printing platform 1, there are air suction holes 11 located in the concave planes. The height difference H between the convex 2 planes and the concave 3 planes is greater than or equal to AE/(2N), AE is the increase in length after the medium absorbs the ink, and N is the amount of the convex planes on the build platform across the entire width in the X direction, as shown in Figure 8.

[0036] Preferably, the height difference H between the convex and concave planes is greater than or equal to 0.1 mm and less than or equal to 0.8 mm; and the width of the concave planes in the X direction is greater than 0.4 mm.

[0037] As shown in Figure 9, the convex and concave parts of the printing platform of this invention are distributed horizontally and evenly on the platform according to the widths of A and B. As shown in Figure 10, AE is digested and absorbed by a plurality of evenly distributed convex and concave quantities. In the actual test, after obtaining the proper H value, even in a more severe sensitive color, such as gradient and neutral gray color transition image, the platform has no visible influence on the printing effect. Figure 11 is the actual measurement result of the impression after the application of the platform principle, and it can be seen that it is no longer in the uncontrollable bulging state as in Figure 5 and Figure 6. The middle in Figure 11 it may already be fully adhered to the surface of the printing platform, and there are no abnormal parts especially protruding. In this state, the print quality can be greatly improved, and the print head wear problem is solved, so that the equipment can work stably for a long time under difficult working conditions.

[0038] As shown in Figure 12 and Figure 13, the guide sections B and C are arranged additionally between the paper feed table and the printing table, while the guide section E is additionally arranged between the paper exit table and the printing table, the height of the highest point of the sections B, C and E is less than the height of the concave planes of the build platform. The height of the highest part of the paper exit platform may be less than the height of the convex planes of the printing platform (the height of the highest part of the paper exit platform may also be less than the height of the concave planes), therefore, the medium can be sufficiently adsorbed to the concave planes under the combined action of the winding tension and the air suction force as shown in the figures, which enables the adsorption and effective digestion of the amount of swelling of the medium.

[0039] Preferably, as shown in Figure 14, several air suction holes are provided on the printing platform 1 located on the convex planes 2, and in order to further improve the air suction effect of the printing platform, the additional design of some 12 grooves or other small concave planes can be adopted, as shown in Figure 14, the suction force distribution principle is that the suction force in the concave planes is stronger than in the convex planes.

[0040] The shape of the convex planes is combined with the shape of the concave planes on the printing platform 1 of this invention, as shown in Figures 15-19, the convex planes 2 and the concave planes 3 on the platform printing 1 can have mutually combined shapes, such as rectangle, triangle, wave shape or other suitable shapes. As shown in Figure 16, the concave planes are closed at the paper feed end, their width gradually increases along the width of the printer, that is, in the paper exit direction, and they are fully open. when reaching the exit end of the paper.

[0041] As shown in Figure 19, a convex plane a is arranged between the convex planes of the printing platform 1, said convex plane 1 starts from the paper feeding end and ends at a certain position of the printing platform. printing, and the convex plane a and the convex planes extending along the entire width of the printing platform are alternately provided.

[0042] As shown in Figure 20, several printing platforms can be joined together to form a relatively large printing platform, in Figure 20 only the splicing of part of the printing platforms with convex planes of different shapes is shown. of the present invention, and the present invention is not limited to what is shown in Figure 20.

[0043] Considering that the amount of ink absorption is gradually increased over several passes for most ink absorption printing, the concave area may be relatively narrow at first, and gradually widens toward the Y-direction (direction of ink exit). paper, that is, near the paper winding direction), as shown in Figure 15, the concave area is narrow at the front and wide at the rear, and gradually increases, but both are open.

[0044] Further, as shown in Figure 16, the concave area at the front end is closed, this place is the print start area, which is fully flush with the convex planes; the rear end is fully open at the paper exit side, and this place is the print finishing area. This way is possibly more suitable for machines with multiple print heads whose Y print direction is relatively wide.

[0045] The deformed platform processing contains several pattern structures, and is exemplified, but not limited to Figure 17.

[0046] The convex planes contract to be ribs, as shown in Fig. 18. This situation is suitable for media with relatively strong stress and relatively high hardness, and can relatively diffuse the radian shift of some ribs.

[0047] Based on the above embodiments and taking into account the characteristic of gradually increasing the amount of ink, relatively dense ribs are distributed in the initial section of the platform, and the exit end of the paper is open, as is shown in Figure 19.

[0048] The printing platform of the present invention has the feature of splicing along the longitudinal direction (Y direction), and can be applied to printing equipment with integration of more sprayers. As shown in Figure 20, all cases have the characteristic of horizontal infinity splice (X direction). Splicing generally refers to the situation that the printing platform is manufactured segmentally by plastic molds or metal casting molds. If integral profile processing is adopted, there may be fewer splices or no splices.

Claims (8)

1. Printing platform structure comprising a printing platform (1) located between a paper feed platform and a paper output platform, where there are several convex planes (2) and concave planes (3) formed on one side which is in contact with the printing medium, where the convex planes (2) and the concave planes (3) alternately lie along the X direction of the printing platform, and extend along the Y direction of the printing platform; where the paper exit ends of the concave planes (3) are free of any bulging structure, characterized by the fact that on the printing platform (1) there are several air suction holes (11) located in the concave planes (3); Y the difference in height H between the convex planes (2) and the concave planes (3) is greater than or equal to AE/(2N), AE is the length increased after the medium absorbs the ink, and N is the amount of the convex planes on the printing platform. 2. The printing platform structure according to claim 1, wherein there are several air suction holes (11) in the printing platform (1) located on the convex planes (2). 3. The printing platform structure of claim 1, wherein the concave planes (3) at the paper feed end are closed, and the width of the concave planes (3) gradually increases along the direction paper exit port on the print bed (1). 4. The printing platform structure according to any of claims 1 and 2, wherein a convex plane a with a relatively small length is provided on the printing platform (1), the convex plane a starts from the feeding end of the paper, and the convex plane a and the convex planes (2) of the printing platform are distributed alternately. 5. Printing platform structure according to any of claims 1 and 2, in which there are several slots (12) or other auxiliary air suction structure in the convex (2) and concave (3) planes of the printing platform (one). 6. Printing platform structure according to any of claims 1 and 2, in which the height of the highest part of the paper output platform is less than the height of the convex planes (2) of the printing platform (1) or less than the height of the concave planes (3). 7. Printing platform structure according to any of claims 1 and 2, wherein the guide sections B and C are further arranged between the paper feeding platform and the printing platform (1), while a guide section guide E is additionally arranged between the paper exit stage and the printing stage (1), and the height of the highest point of the sections B, C and E is less than the height of the concave planes (3) of the print platform (1). The printing platform structure according to any one of claims 1 and 2, wherein the printing platform (1) is a relatively large printing platform made up of a plurality of platforms that are joined together.