WO2019037560A1

WO2019037560A1 - Printing platform for inkjet printing equipment

Info

Publication number: WO2019037560A1
Application number: PCT/CN2018/095743
Authority: WO
Inventors: 李支斌
Original assignee: 杭州专色数码科技有限公司
Priority date: 2017-08-25
Filing date: 2018-07-16
Publication date: 2019-02-28
Also published as: EP3575094A4; EP3575094A1; CN107364242A; EP3575094B1; CN107364242B; ES2900498T3

Abstract

A printing platform (1), located between a paper feeding platform and a paper discharging platform (e). The surface of the printing platform (1) in contact with a printing medium is provided with a plurality of convex planes (2) and downwards-concave planes (3) which are staggered in the X direction of the printing platform (1) and stretch across the Y direction of the printing platform (1). The paper discharging ends of the downwards-concave planes (3) are arranged in an opening manner.

Description

Printing platform of inkjet printing device

Technical field

The present invention relates to the field of printers, and more particularly to a media-supported printing and printing platform for an inkjet printing device.

Background technique

As the main equipment for digital printing, printers are becoming more and more widely used. As the mainstream of printing equipment, inkjet printing can be printed on a variety of different media, such as various paper, polymer film media and film, all kinds of cloth, etc., is playing an increasingly important role. Color inkjet has high requirements for color reproduction. Generally, the printed medium controls the diffusion of ink droplets and absorbs ink by coating or treating the surface of the substrate. For paper or other water-absorbing medium whose medium substrate is plant fiber, after the inkjet, the substrate will be deformed by the absorption of the ink, and local bulging will occur on the printing platform, which will affect the printing precision effect, and the heavy one will scratch. To the print head, causing expensive nozzle damage or scrapping of printed products. This problem has increasingly affected the normal operation of printers, especially in the field of productive applications, such as digital textile printing industrial decorative painting, which has a particularly high requirement for work stability. Since the effective distance accuracy of the print head and the platform has a significant influence on the printing effect, the traditional machine design tries to ensure the flatness of the printing platform, and minimizes the spacing between the nozzle and the printing platform, as well as the printing platform and the inkjet printing machine. The parallelism between the movements. Therefore, the printing platform is very flat, especially in the production of large format printing equipment. However, in order to effectively control the problem that the medium bulges on the platform after absorbing the printing liquid.

Conventional printing platform design, need to ensure the flatness, while arranging some suction structure, so that the medium is close to the platform, there are three typical types:

1. The platform is arranged with a certain density of suction holes, which generates low pressure adsorption through the fan below the platform, as shown in Figure 1 and Figure 2.

2. The platform is equipped with some suction holes, and combined with some groove design to increase the suction area. The groove design is generally based on the material selected for the platform. There are two types:

(1) Injection molding plastic platform or casting mold metal platform, generally can use some oblique or criss-crossing grooves to increase the suction area and increase the suction uniformity. As shown in Figure 3.

(2) Extrusion profile platforms, such as platforms for processing aluminum extrusion materials, may arrange some lateral grooves in the length direction of the extrusion.

3. A few companies will also use the platform to arrange some suction holes, and dig a large area around the suction holes to form some shallow suction pools to increase the suction area. However, such structures are generally designed to improve the suction effect, so the outer circumference of the pool is flush with the printing platform to ensure that the height of the paper is substantially unaffected. As shown in Figure 4.

technical problem

The prior art defect: since the water absorbing medium absorbs the ink, the substrate is caused to expand, and the medium is in the paper feeding direction (Y direction) due to the combination of the paper feeding wheel pushing and the winding direction of the paper feeding direction. Irregular vertical arching creates a drum that affects print quality. When the partial drum height is high, the print head is scratched and the screen is scrapped. The wrinkling and bulging in actual work is shown in Fig. 5 and Fig. 6. The position and height of the wrinkles are uncertain.

Technical solution

In order to solve the deficiencies in the prior art, the present invention provides a printing platform structure capable of uniformly absorbing the bulging of the medium and significantly eliminating the upward arching of the medium. This completely prevents the media from squeezing and scratching the print head, and improves the image quality and printing results.

A printing platform is disposed between a paper feeding platform and a paper discharge platform, and a side of the printing platform contacting the printing medium is provided with a plurality of convex planes and a concave plane, the convex planes and The concave planes are staggered with each other along the X direction of the printing platform, and the convex plane and the concave plane straddle the Y direction of the printing platform; the lower concave plane is provided with an opening end (not prefabricated with a convexity) The structure of the plane height).

Preferably, the printing platform located on the concave plane is provided with a suction hole.

Preferably, the printing platform located on the convex plane is provided with a plurality of air suction holes.

Preferably, the height difference H between the convex plane and the concave plane is greater than or equal to ΔE/(2N), ΔE is the length increased after the medium absorbs the ink, and N is the number of convex planes on the printing platform.

More preferably, the height difference H between the convex plane and the concave plane is greater than or equal to 0.1 mm and less than or equal to 0.8 mm; and the lateral width of the concave plane is greater than 0.4 mm.

Preferably, the concave plane at the paper feed end is closed, and the concave plane gradually increases in width along the paper discharge direction of the printing platform.

Preferably, the printing platform is further provided with a length of a convex plane a, which starts from the paper feeding end, and the convex plane a is staggered with the convex plane of the printer platform.

Preferably, a plurality of grooves or other auxiliary suction structures are formed on the convex plane and the concave plane of the printing platform.

Preferably, the height of the highest portion of the paper discharge platform is less than the height of the convex plane of the printing platform or less than the height of the concave plane.

Preferably, a guiding section B segment and a C segment are added between the paper feeding platform and the printing platform, and a guiding segment E segment is added between the paper discharging platform and the printing platform, and the height of the highest point of the BCE segment is smaller than printing. The height of the concave plane of the platform.

Preferably, the printing platforms can be spliced to each other.

The definition of "printing platform" (or "printing platform" and "printing main platform") in the present invention refers to a platform with a partial width corresponding to the width (Y direction) of the printing head, that is, the real-time spraying of the printing head when the printer is in operation. The platform part corresponding to the ink. Sometimes referred to as the main printing platform in the industry. In the printer structure, there is often an auxiliary paper feed platform at the front end of the printing platform (near the paper feed shaft); and an auxiliary paper output platform at the rear end of the printing platform (near the winding portion).

All of the raised planes extend longitudinally throughout the width of the platform (Y-direction), and all of the concave planes extend longitudinally throughout the width of the platform (Y-direction).

There should be no transverse or (X-direction) ribs or other structures in the concave plane to affect the overall concave absorption and longitudinal motion of the medium. If the suction effect is enhanced, the arranged rib structure needs to be lower than the convex plane. Since the inkjet is generally multi-PASS superimposed, the amount of ink is gradually increased toward the rear end (the paper exit end), so the paper exit end of the concave plane cannot be raised high, and the front end (near the paper feed end) is more ink. Low, it is possible to arrange the structure such as “ribs” moderately, which can be flush with the plane of the protrusion. The paper exit end of the concave plane is penetrated, and there is no high-rise structure. The overall sinking design of the auxiliary paper discharge platform combined with the rear end (below the convex plane or not lower than the concave plane) constitutes the gist of the present invention. This is also the fundamental point of the present invention in the processing principle and design of the printing medium bulging different from other manufacturers.

All of the concave planes must have sufficient width to facilitate the media to sag under the aid of suction and to absorb the amount of expansion of the medium. Generally, the lateral width of each concave plane should be greater than 5 mm. The specific need to calculate and evaluate the test according to the rigidity of the medium and the suction suction force and the tension of the winding.

The height difference between the convex plane and the concave plane is small. For a print head with a low flying speed and a small ink drop, it is generally between 0.1 mm and 0.8 mm. For a print head with fast ink droplets and large ink drops, the height difference can be moderately large, and the maximum is generally no more than 4 mm.

A large overall expansion absorption is achieved by distributing a sufficient number of raised and depressed planes throughout the platform. When the overall absorption amount is sufficient for the use, the height difference between the convex plane and the concave plane is minimized to ensure that the printing effect is not affected.

The suction holes or other suction structures are mainly arranged in the concave planar area. A certain number of suction holes are also arranged on the convex plane, and may not be arranged in the convex plane.

The platform is more suitable for plastic mold making or metal casting mold segmentation production. Machining methods can also be used, but the relative cost is relatively high. It is also possible to use other auxiliary means such as a pasting method to manufacture the convex plane.

The height of the highest part of the rear end discharge platform should be lower than the height of the convex plane, at least close to the concave plane.

The portion of the rear end of the paper exit platform can also be vacated for a free distribution of the arched portion of the medium.

Structural analysis and design implementation:

1. Under normal conditions, the medium will swell after absorbing ink. For example, a medium of normal length L increases the length after absorption by ΔE. As shown in Figure 8. The size of ΔE depends on a number of factors such as the dielectric substrate and coating characteristics, the amount of ink printed, the printing speed, and the residence time. But generally can be based on actual working conditions test.

Second, at present, several working platforms on the market, under the combined effect of medium friction, roll tension, suction suction, and picture ink distribution, irregular local arching will occur. As shown in Figure 8, Figure 5, Figure 6. Moreover, the feature is that the height of the arch is different and unpredictable, resulting in localized special protrusions.

The structural design of the new printing platform is shown in Figure 9. The projections and depressions of the platform are evenly distributed across the platform in accordance with the width of A and B. The height of the bump is H. The size of A and B needs to be determined according to the thickness and rigidity of the medium, the water absorption characteristics of the dielectric coating, the strength of the suction, and the pulling force of the paper. In practice, it can be tested by working conditions. In general, A can be smaller. B needs to be of sufficient size to overcome the rigidity of the medium and smoothly sag under the combined action of suction and winding tension. The size of H can be calculated from the number of protrusions N and the total ΔE over the entire width of the platform:

H≧ΔE/(2N)

Under the absorption condition satisfying ΔE, H should be minimized to ensure that the printing effect is not affected. The effect of the design scheme is shown in Fig. 10. ΔE is digested and absorbed by a number of uniformly distributed irregularities. In the actual test, we obtained the appropriate size of H, even in the most severe sensitive colors, such as neutral gray and gradient color transition images, the platform has no visual impact on the printing effect. Therefore, this patent is highly implementable. As shown in FIG. 11, the actual measurement after the implementation of the principle of the platform can be seen that it is no longer the uncontrollable state of the protrusions in FIG. 5 and FIG. The medium in Figure 11 has been able to fully conform to the surface of the printing platform without special abnormal protrusions. This state can greatly improve the print quality and solve the problem of scratching the print head, so that the device can work stably for a long time under complicated working conditions.

The principle of the present invention is based on the bulging deformation of the in-situ absorption medium, so that the concave planes at the paper exit end in the Y direction are all open-ended, which is the point of distinction. That is, the concave plane does not have other structures at the exit end, and at the same time, the further sinking design of the paper discharge platform can be combined, so that the expansion amount of the medium is sufficiently lowered to be close to the lower concave plane to obtain the absorption.

On the basis of theory and testing, the invention breaks through the conventional reconfiguration of the platform, controls the problem of media bulging, and does not affect the overall printing accuracy, thereby ensuring the printing medium in various ink quantities and water-absorbing media. Long-term stable work. The invention has been designed and produced for the products, and is used in batches for industrial customers, and has achieved remarkable results.

Why can't the traditional platform structure solve the inflation problem? Because the previous industry's thinking is basically to flatten the medium or absorb the wind by external force. However, due to the uneven distribution of the modulus of the printing area and the rigidity of the medium itself hindering the uniform conduction of the tensile force, the effect cannot be solved. Similarly, the strong adsorption itself and the transport of the medium are contradictory, and the rigidity of the medium and the characteristics of the indeterminate area of the ink jet are also destined to have poor adsorption performance. Moreover, fundamentally, if a flat platform does not have a longitudinal structure that accommodates excess dimensions, it is impossible to fundamentally solve the problem of increased ΔE size of the media bulging, and finally only ΔE can be measured at several heights. Wrinkles up, causing the print head to scratch and damage the picture. As shown in Figure 8, Figure 5, Figure 6.

Beneficial effect

It solves the problem of drumming of inkjet printing media that has long plagued the industry for a long time, especially for large-volume wide-format printing devices. Through the platform's ground-breaking non-planar embossing design, it is cleverly based on the bulging deformation of the local absorption medium. The unevenness of the platform that the industry is worried about will affect the printing effect. Since the ink droplets fly vertically downwards, a slight height difference can be ignored within a certain stroke. The actual test also proved that the printed effect is better than the original. It is this tiny height difference H that, through the accumulation of many segments, can eventually digest a large ΔE, which perfectly solves this problem.

DRAWINGS

1 is a three-dimensional effect diagram of a printing platform portion of a conventional printing apparatus.

2 is a three-dimensional wire block diagram of a printing platform portion of a conventional printing apparatus.

Figure 3 is a print device platform with a grooved design on the market.

Figure 4 is a printing device platform with a suction basin on the market.

Figure 5 is a photograph of a swell of the printing platform.

Figure 6 is a photograph of a swell of another printing platform.

Figure 7 is a three-dimensional rendering of the platform of the inventive concept.

Fig. 8 is a schematic view showing the analysis of the bulging profile of the printing platform on the market.

Figure 9 is a schematic view showing the principle of the platform structure of the present invention.

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

Figure 11 is a photograph of a practical application test of the present invention.

Figure 12 is a three-dimensional design of the front and rear auxiliary platform of the present invention (Embodiment 1).

Fig. 13 is a view of the essential points and working states of the front and rear auxiliary platforms of the present invention (Embodiment 1).

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

Figure 15 is a schematic view of Embodiment 3 of the present invention.

Figure 16 is a schematic view of Embodiment 4 of the present invention.

Figure 17 is a schematic view of Embodiment 5 of the present invention.

Figure 18 is a schematic view of Embodiment 6 of the present invention.

Figure 19 is a schematic view of Embodiment 7 of the present invention.

Figure 20 is a schematic view of Embodiment 8 of the present invention.

LIST OF REFERENCE NUMERALS: a-suction hole, b-jet ink cart, c-pressure feed roller, d-printing platform, e-paper exit platform, f-suction hole and suction groove, f'-assisted suction Vortex pool, 1-printing platform, 2-bump plane, 3-lower plane, 11-suction hole, 12-groove.

BEST MODE FOR CARRYING OUT THE INVENTION

The present invention is further described below in conjunction with the accompanying drawings:

1 to 6 show the case of a printer in the prior art, and Fig. 1 is a three-dimensional effect view of a printing platform portion of a conventional printing device. 2 is a three-dimensional wire block diagram of a printing platform portion of a conventional printing apparatus. Figure 3 is a print device platform with a grooved design on the market. Figure 4 is a printing device platform with a suction basin on the market. Figure 5 is a photograph of a swell of the printing platform. Figure 6 is a photograph of a swell of another printing platform.

A printing platform structure comprising a vertical convex plane with a certain width, uniformly distributed in the X direction of the entire platform (ie, the printing width direction); and a concave plane of a certain width, and the convex plane are alternately arranged. Moreover, a plurality of suction holes are arranged in the concave plane, and a certain number of suction holes or convex surfaces are also arranged on the convex plane. As shown in Figure 7.

Figure 7 is a schematic view showing the structure of the present invention. The printing platform structure of the present invention comprises a printing platform between the paper feeding platform and the paper discharge platform, and the printing platform 1 is provided with a plurality of sides in contact with the printing medium. a convex plane 2 and a concave plane 3 which are staggered with each other along the length direction of the printing platform 1, and the convex plane and the concave plane straddle the Y direction of the printing platform 1 ( Along the paper exit direction of the printing platform). The lower concave plane 3 is provided with an opening, that is, the lower concave plane does not have other structures that are raised at the outlet end. The printing platform 1 on the concave plane is provided with a suction hole 11; the height difference H between the convex plane 2 and the concave plane 3 is greater than or equal to ΔE/(2N), and ΔE is increased after the medium absorbs ink. The length, N is the number of convex planes in the width of the entire X direction of the printing platform, as shown in FIG.

Preferably, the height difference H between the convex plane and the concave plane is greater than or equal to 0.1 mm and less than or equal to 0.8 mm; and the X-direction of the concave plane is greater than 4 mm.

As shown in Figure 9, the projections and depressions of the printing platform of the present invention are laterally uniform across the platform in accordance with the width of A and B. As shown in Fig. 10, ΔE is digested and absorbed by a plurality of uniformly distributed unevenness amounts. In the actual test, we obtained the appropriate size of H, even in the most severe sensitive colors, such as neutral gray and gradient color transition images, the platform has no visual impact on the printing effect. As shown in FIG. 11, the actual measurement after the implementation of the principle of the platform can be seen that it is no longer the uncontrollable state of the protrusions in FIG. 5 and FIG. The medium in Figure 11 has been able to fully conform to the surface of the printing platform without special abnormal protrusions. This state can greatly improve the print quality and solve the problem of scratching the print head, so that the device can work stably for a long time under complicated working conditions.

As shown in FIG. 12-13, a guiding section B segment and a C segment are added between the paper feeding platform and the printing platform, and a guiding segment E segment is added between the paper discharging platform and the printing platform, and the guiding segment BCE segment is added. The highest point is less than the height of the concave plane of the printing platform. The height of the highest part of the paper discharge platform may be smaller than the height of the convex plane of the printing platform (the height of the highest part of the paper discharge platform may also be smaller than the height of the concave plane), and the medium is pulled up as shown in the figure. Under the combined action of the suction suction, it will fully adsorb to the concave plane, so as to effectively absorb the expansion amount of the digestive medium.

Preferably, as shown in FIG. 14, the printing platform 1 on the convex plane 2 is provided with a plurality of air suction holes. In order to further improve the air suction effect of the printing platform, some grooves 12 or other small holes may be further assisted. The design of the concave plane, as shown in Figure 14, is based on the principle that the suction plane is larger than the convex plane.

In the present invention, the shape of the convex plane on the printing platform 1 is matched with the shape of the concave plane. As shown in FIGS. 15-19, the convex plane 2 and the concave plane 3 on the printing platform 1 may have a mutual matching shape. If it can be rectangular, triangular, wavy or other suitable shape; the concave plane shown in Figure 16 is closed at the paper feed end, and its width gradually increases along the width direction of the printer, that is, the paper exit direction, reaching out The concave plane at the end of the paper is completely open.

As shown in FIG. 19, a convex plane a is further disposed between the convex planes of the printing platform 1, and the convex plane 1 starts at the paper feeding end and terminates at a certain position on the printing platform. The plane a is interlaced with the raised planes across the width of the printing platform.

As shown in FIG. 20, a plurality of printing platforms can be spliced together to form a larger printing platform, and FIG. 20 is only a splicing between the printing platforms of the convex planes having different shapes of the present invention. It is not limited to that shown in FIG.

Considering that most of the ink is printed, the PASS gradually increases the amount of ink absorbed, so the depressed area can be narrower at the beginning, and gradually widened in the Y direction (the direction of the paper exit, that is, near the winding paper), as shown in the figure. As shown in Fig. 15, the concave area is narrow and wide at the front, and gradually increases, but they are all released.

Further extreme, as shown in Fig. 16, the front recessed area is closed, where the initial print area is completely flush with the raised plane; the rear end is completely released at the exit portion, here the end print position. This approach may be appropriate for printing Y to a wider multi-header machine.

Deformed platform treatment, including various tread configurations, by way of example and not limitation.

The convex plane is reduced to the way of becoming a rib, as shown in FIG. This kind of situation is more suitable for media with higher tension and higher hardness, which can relatively diffuse the curvature of some ribs.

On the basis of the above embodiment, considering the progressive increase characteristic of the ink absorption amount, a dense rib is arranged at the beginning of the platform, and is released at the paper discharge end, as shown in FIG.

The printing platform of the present invention has the characteristics that the longitudinal direction (Y direction) can be spliced, and can be used for a printing apparatus in which more nozzles are integrated. As shown in Figure 20. All of the embodiments have a horizontal (X-direction) infinite splicing property. Stitching generally refers to the case where the printing platform is manufactured by plastic mold or metal casting mold. If the overall profile is processed, there may be little or no splicing.

Embodiments of the invention

The description paragraphs of the embodiments of the present invention are entered here.

Industrial applicability

Type the industrial usability description paragraph here.

Sequence table free content

Type the sequence table free content description paragraph here.

Claims

A printing platform structure comprising a printing platform between a paper feeding platform and a paper discharge platform, wherein: the printing platform is provided with a plurality of convex planes and concave planes on a side in contact with the printing medium. The raised plane and the concave plane are staggered with each other along the X direction of the printing platform, and the convex plane and the concave plane straddle the Y direction of the printing platform; the lower concave plane of the paper exit is open.
A printing platform structure according to claim 1, wherein the printing platform located on the concave plane is provided with a suction hole.
The printing platform structure according to claim 1 or 2, wherein the printing platform located on the convex plane is provided with a plurality of air suction holes.
A printing platform structure according to claim 1, wherein a height difference H between said convex plane and a concave plane is greater than or equal to ΔE/(2N), and ΔE is an increased length after the medium absorbs ink, N Is the number of raised planes on the print platform.
A printing platform structure according to claim 1, wherein said concave plane at the paper feed end is closed, and the concave plane gradually increases in width along a paper discharge direction of the printing platform.
A printing platform structure according to any one of claims 1 to 4, characterized in that the printing platform is further provided with a convex plane a having a smaller length, the convex plane a starting from the paper feeding end. The raised plane a is staggered with the convex plane of the printer platform.
A printing platform structure according to any one of claims 1-4, wherein a plurality of grooves or other auxiliary suction structures are formed on the convex plane and the concave plane of the printing platform.
A printing platform structure according to any one of claims 1 to 4, characterized in that the height of the highest portion of the paper discharge platform is smaller than the height of the convex plane of the printing platform or smaller than the height of the concave plane.
A printing platform structure according to any one of claims 1 to 4, characterized in that: between the paper feeding platform and the printing platform, a guiding section B segment and a C segment are added, between the paper discharging platform and the printing platform. A segment E segment is added, and the height of the highest point of the BCE segment is smaller than the height of the concave plane of the printing platform.
A printing platform structure according to any of claims 1-4, wherein the printing platforms are spliced to each other.