CN107364242B

CN107364242B - A printing platform for inkjet printing equipment

Info

Publication number: CN107364242B
Application number: CN201710747038.9A
Authority: CN
Inventors: 李支斌
Original assignee: Hangzhou Zhuanse Digital Technology Co ltd
Current assignee: Hangzhou Zhuanse Digital Technology Co ltd
Priority date: 2017-08-25
Filing date: 2017-08-25
Publication date: 2020-05-08
Anticipated expiration: 2037-08-25
Also published as: EP3575094B1; ES2900498T3; EP3575094A1; WO2019037560A1; CN107364242A; EP3575094A4

Abstract

The invention relates to the field of printers, in particular to a printing platform, the printing platform is located between a paper feeding platform and a paper output platform, and a surface of the printing platform in contact with the printing medium is provided with several convex planes and concave depressions plane, the convex plane and the concave plane are staggered along the X direction of the printing platform, and the convex plane and the concave plane span the Y direction of the printing platform; the paper exit end of the concave plane is open of. The invention well solves the problem of drumming of the inkjet printing medium that has plagued the industry for a long time, especially the large ink volume and wide format printing equipment. Through the breakthrough non-planar concave-convex design of the platform itself, it is subtly based on the bulging deformation of the in-situ absorption medium. The original industry worried that the uneven platform will affect the printing effect. Since the ink droplets fly vertically downward, within a certain stroke, the slight height difference can be ignored. The actual test also proved that the printing effect is better than the original.

Description

Printing platform of ink-jet printing equipment

Technical Field

The invention relates to the field of printers, in particular to a medium bearing jet printing platform of an ink jet printing device.

Background

Printers are becoming widely used as the main devices for digital printing. Inkjet printing is the mainstream of printing equipment, and can realize inkjet printing on various media, such as various papers, polymer film media, films, various kinds of cloth, and the like, and plays an increasingly important role. Because of the high requirements for color reduction, color inkjet printing is generally used for printing media by applying a coating or treatment to the surface of a substrate to control the spreading of ink droplets and absorb ink. For paper with plant fiber as a medium substrate or other water-absorbing media, after ink is jetted, the substrate can expand and deform due to ink absorption and generate local swelling on a printing platform, so that the printing precision effect is influenced by a light person, and a printing head is scraped by a heavy person, so that an expensive nozzle is damaged or a batch of printed products are scrapped. This problem has increasingly affected the proper functioning of the printer, especially in the field of productive applications, such as the printing of decorative drawings in the digital textile printing industry, where the stability requirements for the operation are particularly high. Because the effective distance precision of the printing head and the platform has obvious influence on the printing effect, the traditional machine design tries to ensure the smoothness of the printing platform, reduces the distance between the spray head and the printing platform as much as possible, and ensures the motion parallelism between the printing platform and the spray printing ink vehicle. Therefore, the printing platform is flat, especially in a large-format printing device with productivity. However, in order to effectively control the problem that the medium swells and deforms on the platform after absorbing the jet printing liquid.

The conventional printing platform design needs to ensure flatness, and arranges some air suction structures to ensure that media are tightly attached to the platform, wherein the conventional printing platform design typically comprises the following three types:

1. the platform is provided with a certain density of air suction holes, and low-pressure adsorption is generated by a fan below the platform, as shown in figures 1 and 2.

2. The platform is provided with a plurality of air suction holes and is combined with a plurality of groove designs for enlarging air suction area. The trench design is generally divided into two types according to the material selected by the platform:

(1) the injection molding plastic platform or the casting mold metal platform can flexibly adopt a plurality of oblique or criss-cross grooves to increase the air suction area and increase the air suction uniformity. As shown in fig. 3.

(2) Extruded profile platforms, such as those used in processing aluminum alloy extruded stock, may have transverse grooves running the length of the extrusion.

3. A few companies also adopt the platform to arrange a plurality of air suction holes, and dig a large area around the air suction holes to form a plurality of shallow air suction pools to increase the air suction area. However, such structures are generally designed with a view to improving the air suction effect, and therefore, the outer ring of the pool is flush with the printing platform, so that the height of the paper is not affected basically. As shown in fig. 4.

The prior art has the defects that: the absorbent media can cause the base material to swell after absorbing ink, and the media is pushed out by the paper feeding wheel and rolled and pulled in the paper collecting direction, so that the media generate irregular vertical arching and bulging in the paper feeding direction (Y direction), and the printing image quality is influenced. When the local rise height is high, the print head is scratched and the picture is discarded. The wrinkling bulge condition in actual work is shown in fig. 5 and 6, and the position and height of wrinkling have uncertainty.

Disclosure of Invention

In order to solve the defects in the prior art, the invention provides the printing platform structure which can uniformly absorb medium bulging and obviously eliminate the upward arching of the medium. Thereby thoroughly avoiding the medium from bulging and scratching the printing head and improving the image quality and the printing effect.

A printing platform is positioned between a paper feeding platform and a paper discharging platform, a plurality of convex planes and concave planes are arranged on one surface of the printing platform, which is contacted with a printing medium, the convex planes and the concave planes are arranged in a staggered manner along the X direction of the printing platform, and the convex planes and the concave planes stretch across the Y direction of the printing platform; the paper outlet end of the lower concave plane is arranged in an opening mode (a structure close to the height of the convex plane cannot be preset).

Preferably, the printing platform positioned on the lower concave plane is provided with an air 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 Δ E/(2N), Δ E is the length of the medium after absorbing 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 more than or equal to 0.1mm and less than or equal to 0.8 mm; the transverse width of the concave plane is more than 0.4 mm.

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

Preferably, the printing platform is further provided with a section of protruding plane a with a smaller length, the protruding plane a starts from the paper feeding end, and the protruding plane a and the protruding plane of the printing platform are arranged in a staggered mode.

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

Preferably, the height of the highest position of the paper discharge platform is smaller than the height of a convex plane of the printing platform or smaller than the height of a concave plane.

Preferably, a guide section B section and a guide section C section are additionally arranged between the paper feeding platform and the printing platform, a guide section E section is additionally arranged between the paper discharging platform and the printing platform, and the height of the highest point of the BCE section is smaller than the height of the lower concave plane of the printing platform.

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

The definition of "printing platform" (or "jet printing platform" or "main printing 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, a platform part corresponding to the real-time ink jetting of the printing head when the printer is working. Sometimes also referred to in the industry as the main printing platform. In the printer structure, an auxiliary paper feeding platform is often arranged at the front end (near the paper feeding shaft) of the printing platform; an auxiliary paper outlet platform is arranged at the rear end (close to the rolling part) of the printing platform.

All raised planes extend longitudinally through the width (Y-direction) of the entire platform, and all depressed planes extend longitudinally through the width (Y-direction) of the entire platform.

There should be no ribs or other structures in the undercut plane that are as high as the transverse (X-direction) and convex planes to affect the overall undercut absorption and longitudinal motion effects of the media. If it is considered that the suction effect is enhanced, the rib structures are arranged below the plane of the protrusions. Because the ink jet is generally formed by overlapping a plurality of PASS, the ink quantity is gradually increased towards the rear end (paper outlet end), so that the paper outlet end of a lower concave plane cannot be particularly raised, and the front end (close to the paper inlet end) can be properly arranged with structures such as ribs and the like because the ink quantity is lower, and can be maximally leveled with a convex plane. The paper outlet end of the concave plane penetrates through the paper outlet end of the paper outlet device, a raised structure cannot be formed, and the main point of the paper outlet device is formed by combining the integral sinking design (lower than the convex plane or not higher than the concave plane) of the auxiliary paper outlet platform at the rear end. This is also the root of the present invention in the handling principle and design of print media bulging, which is different from other manufacturers.

All recessed surfaces must be of sufficient width to facilitate the sinking of the media with the assistance of the suction to absorb the amount of expansion of the media. The transverse width of the concave surface of each section should generally be greater than 5 mm. The test is reasonably calculated and evaluated according to the rigidity of the medium, the suction force of air suction and the magnitude of rolling tension.

The difference in height between the convex plane and the concave plane is small. For a print head with low ink drop flying speed and small ink drops, the flying speed is generally between 0.1mm and 0.8 mm. For a printhead with fast ink drop flight and large ink drops, the height difference can be reasonably large, typically no more than 4mm at most.

The large expansion absorption capacity of the whole platform is achieved by uniformly distributing a sufficient number of convex and concave planes on the whole platform. And under the condition that the integral absorption capacity meets the use requirement and is enough, the height difference between the convex plane and the concave plane is reduced as much as possible so as to ensure that the printing effect is not influenced.

Air suction holes or other air suction structures are arranged in the concave plane area in an emphasized mode. A certain number of air suction holes are also arranged on the plane of the bulge, or not arranged on the plane of the bulge.

The platform is relatively suitable for manufacturing plastic molds or producing metal casting molds in sections. And a machining mode can be adopted, but the relative cost is higher. Other aids such as adhesive means may also be used to create the raised flat surfaces.

The height of the highest part of the rear paper outlet platform is lower than that of the convex plane and at least close to that of the concave plane.

The part of the rear paper-out platform can be emptied for a while, which is beneficial to the free dispersion of the arched part of the medium.

Structural analysis and design implementation:

first, in a normal state, the medium swells after absorbing ink. Such as a length of media of normal length L, the length increases by Δ E upon absorption of water. As shown in fig. 8. The magnitude of Δ E depends on many factors, including media substrate and coating characteristics, print ink volume, print speed, and dwell time. But can generally be derived from actual operating conditions.

Secondly, irregular local arching can occur on a plurality of working platforms on the market under the combined action of medium friction force, paper rolling tension, air suction force and picture ink amount distribution. As shown in fig. 8, 5 and 6. Moreover, the characteristic is that the camber is not uniform in height and unpredictable, and locally distinctive protrusions are generated.

The structural design of the new printing platform is shown in figure 9. The bulges and the depressions of the platform are transversely and uniformly distributed on the platform according to the widths A and B. The height of the projections is H. The sizes of A and B are comprehensively determined according to the factors of the thickness and the rigidity of the medium, the water absorption characteristic of the medium coating, the strength of air suction, the tension of the roll paper and the like. And the working condition can be tested in practice. In general, a may be smaller. And B needs to have enough size to overcome the rigidity of the medium and successfully recess under the combined action of suction force and rolling tension. The magnitude of H can then be calculated from the number N of protrusions within the entire width of the platform and the total Δ E:

H≧ΔE/(2N)

under absorption conditions that satisfy Δ E, H should be minimized to ensure that printing is not affected. The effect of the design is shown in fig. 10, where Δ E is digested and absorbed by a number of evenly distributed asperities. In practical tests, after we have found the appropriate size of H, the platform has no appreciable effect on the printing effect even in the most severe images of sensitive colors, such as neutral gray and gradient color transitions. Therefore, the method has high practicability. As shown in fig. 11, the actual printing measurement after the platform principle is implemented can be seen, which is no longer the uncontrollable state of the protrusion in fig. 5 and 6. The media of fig. 11 has been able to fully conform to the surface of the printing platform without the presence of particular anomalous projections. This state can greatly improve the printing quality, solve the problem of scratching the printing head and ensure the equipment to stably work for a long time under complex working conditions.

The principle of the invention is based on the fact that the bulging deformation of the medium is absorbed in situ, so that the concave planes at the Y-direction exit end are all open-ended, which is the distinguishing point. That is, the concave plane does not have other structures of the height at the outlet end, and simultaneously can be combined with the further sinking design of the paper outlet platform, so that the expansion amount of the medium is fully sunk and is close to the concave plane, and the medium is accommodated and absorbed.

On the basis of theory and test, the invention breaks through the conventional reconstruction of the platform, controls the medium bulging problem, and simultaneously does not influence the overall printing precision, thereby ensuring the long-term stable work of the jet printing equipment under various ink quantities and water-absorbing media. The invention has already carried on the design production of the products, and is used for the customer use of trade in batches, have achieved the apparent effect.

Why is the conventional platform structure unable to solve the bulging problem? Because the thought in the prior art is to flatten the medium by external force or strongly suck the medium by air suction. However, the effect is not solved because the uneven distribution of the modulus of the printing area and the rigidity of the medium per se can prevent the uniform transmission of the tensile force. Also, strong adsorption itself is contradictory to the transport of the medium, and the rigidity of the medium and the characteristics of the ink-jetting indeterminate areas are also determined to be poor in adsorption effect. Moreover, if a flat platform is used, there is no structure for longitudinally accommodating and absorbing the excess size, the problem of the increased Δ E size of the media swelling cannot be fundamentally solved, and finally, the Δ E wrinkles upwards at an undetectable height, causing the printing head to scratch and damaging the picture. As shown in fig. 8, 5 and 6.

The invention has the beneficial effects that: the problem of the bulging of the ink-jet printing medium, which is troubled for a long time in the industry, is well solved, and the ink-jet printing medium is particularly suitable for large-ink-volume wide-width printing equipment. The platform is skillfully based on absorbing the bulging deformation of the medium in situ through a breakthrough non-planar concave-convex design. The uneven platform worried in the industry originally can influence the printing effect, and because the ink drops fly vertically downwards, a slightly small height difference can be ignored within a certain stroke. And actual tests also prove that the printing effect is better than the original effect. The small height difference H can be accumulated through distribution of a plurality of sections, and finally, a large Delta E can be digested, so that the problem is perfectly solved.

Drawings

Fig. 1 is a three-dimensional effect diagram of a printing platform part of a conventional printing device.

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

Fig. 3 is a printing apparatus platform with a gutter design on the market.

Fig. 4 is a printing apparatus platform with an air suction pool on the market.

Figure 5 is a photograph of a print deck with measured bulge and corrugation.

Figure 6 is a photograph of measured bulge wrinkles of another printing deck.

Fig. 7 is a three-dimensional effect diagram of a platform of the inventive concept.

Fig. 8 is a schematic diagram of a commercial printing platform bulge and wrinkle profile analysis.

Fig. 9 is a schematic diagram of the platform structure of the present invention.

FIG. 10 is a schematic diagram of the analysis of the effect of the platform structure according to the present invention.

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

FIG. 12 is a three-dimensional design of a mating fore-aft auxiliary platform of the present invention (example 1).

Fig. 13 is a point and operation state annotation of the auxiliary platform before and after the completion of the present invention (example 1).

FIG. 14 is a further design of the present invention (example 2).

Fig. 15 is a schematic view of embodiment 3 of the present invention.

Fig. 16 is a schematic view of embodiment 4 of the present invention.

Fig. 17 is a schematic view of embodiment 5 of the present invention.

Fig. 18 is a schematic view of embodiment 6 of the present invention.

Fig. 19 is a schematic view of embodiment 7 of the present invention.

Fig. 20 is a schematic view of embodiment 8 of the present invention.

Reference numerals: the printing device comprises a suction hole a, a nozzle ink vehicle b, a pressure paper feeding wheel c, a printing platform d, a paper discharging platform e, an air suction hole f, an air suction groove f, an auxiliary air suction concave pool f, a printing platform 1, a convex plane 2, a concave plane 3, an air suction hole 11 and a groove 12.

Detailed Description

The invention is further described below with reference to the accompanying drawings:

fig. 1-6 show a prior art printer, and fig. 1 is a three-dimensional effect diagram of a printing platform part of a conventional printing device. Fig. 2 is a three-dimensional wire frame diagram of a printing platform portion of a conventional printing apparatus. Fig. 3 is a printing apparatus platform with a gutter design on the market. Fig. 4 is a printing apparatus platform with an air suction pool on the market. Figure 5 is a photograph of a print deck with measured bulge and corrugation. Figure 6 is a photograph of measured bulge wrinkles of another printing deck.

A printing platform structure comprises vertical raised planes with a certain width, which are uniformly distributed in the X direction (namely the printing width direction) of the whole platform; meanwhile, concave planes with certain width and convex planes are alternately arranged. And a plurality of air suction holes are arranged in the lower concave plane, and a certain number of air suction holes are also arranged on the convex plane or the convex plane is not arranged. As shown in fig. 7.

Fig. 7 is a schematic structural diagram of the present invention, and the printing platform structure provided by the present invention includes a printing platform located between a paper feeding platform and a paper discharging platform, wherein a plurality of convex planes 2 and concave planes 3 are arranged on a surface of the printing platform 1 contacting with a printing medium, the convex planes 2 and the concave planes 3 are arranged in a staggered manner along a length direction of the printing platform 1, and the convex planes and the concave planes cross a Y direction of the printing platform 1 (along a paper discharging direction of the printing platform). The depressed plane 3 is open-ended, i.e. there is no raised other structure of the depressed plane at the outlet end. An air suction hole 11 is formed in the printing platform 1 on the lower concave plane; the height difference H between the raised plane 2 and the recessed plane 3 is greater than or equal to Δ E/(2N), Δ E is the length of the medium after absorbing ink, and N is the number of raised planes in the entire width of the printing platform in the X direction, as shown in fig. 8.

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

As shown in fig. 9, the projections and depressions of the printing platform of the present invention are laterally evenly distributed on the platform according to the widths a and B. As shown in fig. 10, Δ E is digested and absorbed by the number of uniformly distributed irregularities. In practical tests, after we have found the appropriate size of H, the platform has no appreciable effect on the printing effect even in the most severe images of sensitive colors, such as neutral gray and gradient color transitions. As shown in fig. 11, the actual printing measurement after the platform principle is implemented can be seen, which is no longer the uncontrollable state of the protrusion in fig. 5 and 6. The media of fig. 11 has been able to fully conform to the surface of the printing platform without the presence of particular anomalous projections. This state can greatly improve the printing quality, solve the problem of scratching the printing head and ensure the equipment to stably work for a long time under complex working conditions.

As shown in fig. 12-13, a guiding section B and a guiding section C are additionally arranged between the paper feeding platform and the printing platform, a guiding section E is additionally arranged between the paper discharging platform and the printing platform, and the highest point of the guiding section BCE is smaller than the height of the concave plane of the printing platform. The height of the highest part of the paper discharging platform can be smaller than that of the convex plane of the printing platform (the height of the highest part of the paper discharging platform can also be smaller than that of the concave plane), so that the medium can be fully adsorbed to the concave plane under the combined action of the rolling pulling force and the air suction force as shown in the figure, and the expansion amount of the digestion medium can be effectively absorbed.

Preferably, as shown in fig. 14, the printing platform 1 located on the convex plane 2 is provided with a plurality of air suction holes, and in order to further improve the air suction effect of the printing platform, the design of some grooves 12 or other small concave planes may be assisted, and as shown in fig. 14, the distribution principle of the suction force is that the lower concave plane is larger than the convex plane.

The shape of the convex plane and the shape of the concave plane on the printing platform 1 are matched, as shown in fig. 15-19, the convex plane 2 and the concave plane 3 on the printing platform 1 can be matched with each other, such as rectangle, triangle, wave or other suitable shapes; the depressed plane shown in fig. 16 is closed at the paper feed end, and its width gradually increases in the width direction of the printer, i.e., the paper discharge direction, and the depressed plane reaching the paper discharge end is completely open.

As shown in fig. 19, a section of convex plane a is further provided between the convex planes of the printing platform 1, the convex plane 1 starts from the paper feeding end and ends at a certain position on the printing platform, and the convex plane a and the convex plane across the whole width of the printing platform are staggered.

As shown in fig. 20, several printing platforms can be assembled together to form a larger printing platform, and fig. 20 shows only the assembly of the printing platforms with different shapes of raised planes according to the present invention, and the present invention is not limited to the one shown in fig. 20.

Considering that most of the ink absorption is increased by the PASS, the depressed area may be initially narrower and gradually widen in the Y direction (the paper output direction, i.e. the direction close to the paper roll), as shown in fig. 15, and the depressed area is narrower in the front and wider in the back, and gradually increases, but is released.

Further endpointing, as shown in FIG. 16, the front depressed area is closed, where the initial print area is completely flush with the raised plane; the trailing end is completely released at the paper discharge position, which is the end print position. This approach may be appropriate for printing multiple printhead machines that are wider in the Y-direction.

Modified platform processes, including various tread configurations, by way of example and not limitation, fig. 17.

The raised flat surfaces are reduced to a ribbed pattern as shown in fig. 18. The condition is more suitable for the medium with larger tension and higher hardness, and can relatively diffuse the radian change of some ribs.

On the basis of the above embodiment, in consideration of the gradual increase characteristic of the ink absorption amount, a rib is arranged a little bit densely at the initial stage of the stage and is released at the paper output end as shown in fig. 19.

The printing platform has the characteristic of splicing in the longitudinal direction (Y direction), and can be used for printing equipment with more nozzles. As shown in fig. 20. All embodiments have infinite stitching characteristics in the transverse direction (X direction). Stitching generally refers to the case where the printing platform is manufactured in sections by plastic or metal casting molds. If the integral profile is adopted for processing, little or no splicing is possible.

Claims

1. a printing platform of an inkjet printing device, comprising a printing platform positioned between a paper feeding platform and a paper output platform, it is characterized in that: the one side that the printing platform contacts with the printing medium is provided with several raised planes and the concave plane, the convex plane and the concave plane are staggered along the X direction of the printing platform, and the convex plane and the concave plane span the Y direction of the printing platform; the paper exit end of the concave plane It is set with an opening, and a suction hole is opened on the printing platform on the concave plane; the height difference H between the convex plane and the concave plane is greater than or equal to ΔE/(2N), and ΔE is the length that the medium increases after absorbing ink , N is the number of raised planes on the printing platform.

2 . The printing platform according to claim 1 , wherein the printing platform located on the raised plane is provided with a plurality of air suction holes. 3 .

3 . The printing platform according to claim 1 , wherein the concave plane at the paper feeding end is closed, and the width of the concave plane gradually increases along the paper output direction of the printing platform. 4 .

4. A printing platform according to claim 1 or 2, characterized in that: the printing platform is further provided with a raised plane a with a shorter length, and the raised plane a starts from the paper feeding end, The raised plane a is staggered with the raised plane of the printer platform.

5. A printing platform according to claim 1 or 2, wherein a plurality of grooves or other auxiliary air suction structures are formed on the convex plane and the concave plane of the printing platform.

6 . The printing platform according to claim 1 or 2 , wherein the height of the highest part of the paper output platform is less than the height of the raised plane or the height of the concave plane of the printing platform. 7 .

7. A printing platform according to claim 1 or 2, wherein a guide section B and C are added between the paper feeding platform and the printing platform, and a guide section B and C are added between the paper output platform and the printing platform. For the guide segment E, the height of the highest point of the BCE segment is smaller than the height of the concave plane of the printing platform.

8. A printing platform according to claim 1 or 2, wherein the printing platforms can be spliced with each other.