Paper back coating equipment

Abstract

The utility model belongs to the technical field of paper processing equipment, and particularly relates to paper back coating equipment, which comprises a rack, and further comprises a guide structure comprising a support roller and a plurality of guide rollers and used for guiding and supporting paper; the coating mechanism is arranged on one side of the supporting roller, comprises a supply box and a coating roller arranged on the supply box, and is used for supplying coating liquid and coating the coating liquid onto the paper; the scraper mechanism is arranged on one side of the coating mechanism, is in contact with the paper and comprises a supporting seat and a scraper arranged on the supporting seat; the paper coating device further comprises a lubricating liquid spraying mechanism which is arranged on the other side of the coating mechanism, located on the edge of the supporting roller and used for spraying lubricating liquid to paper. The coating machine has the beneficial effects that the lubricating liquid spraying mechanism is arranged, so that the scraper can be protected and can float on lubricating oil and make contact with the lubricating oil, the scraper is prevented from making direct contact with dry paper without coating liquid, and abrasion is reduced.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of paper processing equipment, and particularly relates to a paper back coating equipment. BACKGROUND

[0002] A corresponding paper back coating equipment is needed to coat a pattern or a coating layer on the base paper to make the paper have different properties.

[0003] Patent with publication number US5048453A discloses a coating device for single or double-sided coating of a running web, comprising at least one backing roll and a coater cooperating with the backing roll to supply the backing roll with a paste or coating agent, and a device for smoothing the material supplied to the web, and optionally, also coating the other side of the web, the coating device comprising a self-supporting coating roll, a hearth whose surface cooperating with the support roll is provided with circumferentially extending, mutually parallel grooves or slots, which provide volumetric or metered application onto the surface of the support roll before contact with the web.

[0004] In the above patent, back coating is performed by the cooperation of the backing roll and the doctor blade. Although the effect of back coating can be achieved, in the prior art, when coating the paper, a part with a width of about 10 mm at the edge of the paper is not coated to avoid the problem that the coating liquid is deposited on the roll. However, the part without coating liquid will accelerate the wear of the doctor blade, and the doctor blade needs to be frequently replaced. The above patent does not solve the related problem, which will lead to frequent replacement of the doctor blade and increase the cost, and needs to be improved. SUMMARY

[0005] The application aims to provide a paper back coating equipment which can solve the above problems.

[0006] The application aims to provide a paper back coating equipment, which comprises a rack, and further comprises:

[0007] A guide structure comprising a support roll and a plurality of guide rolls for guiding and supporting the paper;

[0008] A coating mechanism arranged on one side of the support roll, comprising a supply box and a coating roll arranged on the supply box, for supplying and coating the coating liquid on the paper;

[0009] A doctor blade mechanism arranged on one side of the coating mechanism and in contact with the paper, comprising a support seat and a doctor blade arranged on the support seat;

[0010] Further comprising a lubricating liquid spraying mechanism arranged on the other side of the coating mechanism and located at the edge of the support roll, for spraying the lubricating liquid on the paper.

[0011] The paper back coating device comprises a supporting roller and a plurality of guide rollers for guiding the paper to be smoothly transmitted in the device and ensuring the paper to keep correct position and tension during the coating process. A coating mechanism is installed on one side of the supporting roller and comprises a supply box for storing coating liquid and a coating roller arranged on the supply box for uniformly coating the coating liquid onto the paper. A doctor blade mechanism is installed on one side of the coating mechanism and in contact with the paper and comprises a supporting seat and a doctor blade arranged on the supporting seat for removing the excess coating liquid on the coating roller to ensure the coating quality and simultaneously contacting the non-coated part of the paper edge. A lubricating liquid spraying mechanism is installed on the other side of the coating mechanism and at the edge of the supporting roller for spraying lubricating liquid onto the paper edge. The lubricating liquid is used for protecting the doctor blade so that the doctor blade can "float" on the lubricating oil and contact the lubricating oil to avoid direct contact with the dry paper without coating liquid and reduce the abrasion. The lubricating liquid here can be composed of water and substances dissolved therein such as carboxymethyl cellulose or starch which do not affect the performance of the ordinary coating liquid.

[0012] By spraying the lubricating liquid on the non-coated part of the paper edge, the contact between the doctor blade and the paper is changed from dry friction to lubricated friction, which significantly reduces the abrasion rate of the doctor blade, thereby prolonging the service life of the doctor blade, reducing the need for frequent replacement of the doctor blade and further reducing the equipment maintenance cost and downtime. At the same time, the lubricating liquid is composed of water and harmless substances dissolved therein, which is harmless to the environment.

[0013] Further, the lubricating liquid spraying mechanism comprises:

[0014] a mounting seat arranged on the rack and having a first chamber and a second chamber storing lubricating oil arranged inside;

[0015] a supply pipe arranged on the mounting seat and in communication with the first chamber and the second chamber for providing lubricating oil;

[0016] a spraying structure arranged on the mounting seat and in communication with the chamber for spraying the lubricating oil in the chamber onto the paper;

[0017] wherein the supply pipe has two and each of the supply pipes is provided with a metering pump for controlling metering.

[0018] The mounting seat is mounted on the rack as a support, and a first chamber and a second chamber storing lubricating oil are formed in the mounting seat. The two chambers can store different types of lubricating oil, and different lubricating oil can be sprayed according to requirements. The supply pipe is mounted on the mounting seat and communicates with the first chamber and the second chamber, and is used for conveying external lubricating oil into the first chamber and the second chamber. In order to accurately control the supply amount of lubricating oil, a metering pump is mounted on each supply pipe. The metering pump can accurately adjust the flow of lubricating oil, and ensures the uniformity and stability of spraying. The spraying structure is mounted on the mounting seat and communicates with the chamber, and is used for atomizing and uniformly spraying lubricating oil on the paper.

[0019] During the operation of the paper back coating equipment, when the paper passes through the lubricating liquid spraying mechanism, the lubricating oil in the chamber is conveyed into the spraying structure through the supply pipe under the action of the metering pump. The spraying structure atomizes and uniformly sprays the lubricating oil on the edge of the paper. The existence of the lubricating liquid avoids the direct contact of the scraper with the dry paper, and reduces the wear.

[0020] Further, the spraying structure comprises:

[0021] The first spraying structure is arranged on the mounting seat and connected with the first chamber.

[0022] The second spraying structure is arranged on the mounting seat and communicates with the second chamber.

[0023] The second spraying structure is located above the first spraying structure, and the second spraying structure and the first spraying structure are respectively used for spraying different lubricating oil.

[0024] The spraying structure is responsible for guiding the lubricating oil out of the chamber and uniformly spraying it on the paper. The spraying structure comprises a first spraying structure and a second spraying structure, which are respectively connected to the first chamber and the second chamber. The first spraying structure is mounted on the mounting seat and connected with the first chamber. The second spraying structure is also mounted on the mounting seat and located above the first spraying structure. By arranging two spraying structures and connecting different chambers respectively, different lubricating liquid can be sprayed for different requirements, and the flexibility and diversity of the equipment are improved.

[0025] Further, the first spraying structure comprises:

[0026] The support stand is arranged on the support seat.

[0027] The first guide pipe is arranged at the top of the support stand, one end of the first guide pipe communicates with the first chamber, and the other end of the first guide pipe is provided with a first nozzle.

[0028] The first guide plate is arranged on the support stand, and the surface of the first guide plate is provided with a positioning groove for mounting the first nozzle. The end of the first guide plate away from the support stand is arc-shaped and extends towards the support roller.

[0029] The first guide cavity is formed between the first guide plate and the second spraying structure, and the lubricating liquid is sprayed into the first guide cavity.

[0030] The support stand is installed on the support base as the support basis of the first spraying structure, which provides support to ensure the stability of the first spraying structure during the operation of the equipment. The first guide pipe is installed at the top of the support stand, one end of which is in communication with the first chamber, and is used to transport the lubricating oil in the chamber to the first nozzle, which is used to atomize and uniformly spray the lubricating oil on the paper. At the same time, the length and diameter of the first guide pipe can be adjusted according to the flow of lubricating oil and spraying requirements. The first guide plate is installed on the support stand, and the surface of the first guide plate is provided with a positioning groove for installing the first nozzle, which is used to ensure that the first nozzle is installed at a predetermined position to achieve accurate spraying effect. The end of the first guide plate away from the support stand is arc-shaped and extends towards the support roller, which helps to guide the lubricating oil more uniformly to the paper and reduces splashing and waste during spraying.

[0031] The first guide cavity is formed between the first guide plate and the second spraying structure, and when the lubricating oil is sprayed from the first nozzle, it will enter the first guide cavity and be guided to ensure that the lubricating oil can be accurately and uniformly sprayed to the edge of the paper, so that the edge of the doctor blade can be in contact with the lubricating oil.

[0032] Further, the second spraying structure comprises:

[0033] The limiting seat is provided on the first guide pipe, and the bottom of the limiting seat is provided with an extension plate, and the first guide cavity is located between the extension plate and the first guide plate;

[0034] The second guide pipe is in communication with the second chamber at one end and penetrates the limiting seat at the other end, and the second guide pipe is provided with a second nozzle at the end penetrating the limiting seat;

[0035] The second guide plate is provided on the limiting seat and located on both sides of the second nozzle;

[0036] The second guide plate is arc-shaped and extends towards the support roller, and the second guide cavity is formed between the two second guide plates for spraying the lubricating liquid.

[0037] The limiting seat is installed on the first guide pipe as the support of the second spraying structure, the bottom of the limiting seat is provided with an extension plate, and the extension plate and the first guide plate form a first guide cavity for guiding the lubricating oil sprayed by the first nozzle.

[0038] Further, the first nozzle and the second nozzle are each provided with a plurality of nozzles, and the plurality of first nozzles and the plurality of second nozzles are uniformly distributed.

[0039] In the first spraying structure and the second spraying structure, the first nozzle and the second nozzle are each provided with a plurality of nozzles, and the plurality of first nozzles and the plurality of second nozzles are uniformly distributed.

[0040] The beneficial effects of the present application are as follows:

[0041] 1. By providing the lubricating liquid spraying mechanism, the doctor blade can be protected and can "float" on the lubricating oil and contact the lubricating oil, thereby avoiding direct contact with the dry paper without coating liquid and reducing wear;

[0042] 2. By spraying lubricating liquid on the edge of the paper, the contact between the doctor blade and the paper is changed from dry friction to lubricated friction, which significantly reduces the wear rate of the doctor blade, thereby prolonging the service life of the doctor blade, reducing the need for frequent replacement of the doctor blade, and further reducing equipment maintenance costs and downtime;

[0043] 3. By installing the first guide cavity and the second guide cavity, the splashing and waste of lubricating oil are reduced, and the utilization rate of lubricating oil is improved. BRIEF DESCRIPTION OF DRAWINGS

[0044] Figure 1 is a structural schematic view of the present application;

[0045] Figure 2 is a structural schematic view of the lubricating liquid spraying mechanism of the present application.

[0046] In the figure, the reference signs are: 100, rack; 200, guide structure; 210, supporting roller; 220, guide roller; 300, coating mechanism; 310, supply box; 320, coating roller; 400, doctor mechanism; 410, supporting seat; 420, doctor blade; 500, lubricating liquid spraying mechanism; 510, mounting seat; 511, first chamber; 512, second chamber; 520, supply pipe; 530, first spraying structure; 531, supporting vertical plate; 532, first guide pipe; 533, first nozzle; 534, first guide plate; 535, positioning groove; 536, first guide cavity; 540, second spraying structure; 541, limiting seat; 542, extending plate; 543, second guide pipe; 544, second nozzle; 545, second guide plate; 546, second guide cavity; 550, metering pump. DETAILED DESCRIPTION

[0047] The technical solutions in the embodiments of the present application will be clearly described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art belong to the scope of protection of the present application.

[0048] The terms "first", "second", and the like in the specification and claims of the present application are used to distinguish similar objects, and are not used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged under appropriate circumstances, so that the embodiments of the present application can be implemented in an order other than those illustrated or described herein, and the objects distinguished by "first", "second", etc. are usually a category and do not limit the number of objects, for example, the first object can be one or more. In addition, "and / or" in the specification and claims indicates at least one of the connected objects, and the character " / ", generally indicates that the front and rear associated objects are in a "or" relationship.

[0049] A paper back coating device provided by the embodiments of the present application will be described in detail below with reference to the drawings and specific examples and their application scenarios.

[0050] Embodiment 1:

[0051] As shown in Figure 1 and Figure 2 The embodiments of the present application provide

[0052] A paper back coating device, comprising a rack 100, further comprising:

[0053] A guide structure 200, comprising a supporting roller 210 and a plurality of guide rollers 220, for guiding and supporting paper;

[0054] The coating mechanism 300 is arranged on one side of the supporting roller 210 and includes a supply box 310 and a coating roller 320 arranged on the supply box 310, which is used to supply and coat the coating liquid on the paper;

[0055] The scraper mechanism 400 is arranged on one side of the coating mechanism 300 and in contact with the paper, and includes a supporting seat 410 and a scraper 420 arranged on the supporting seat 410.

[0056] The lubricating liquid spraying mechanism 500 is arranged on the other side of the coating mechanism 300 and at the edge of the supporting roller 210, and is used to spray the lubricating liquid on the paper.

[0057] In some embodiments of the present application, as shown in Figure 1 Fig. 1, a paper back coating device is provided, which includes a supporting roller 210 and a plurality of guide rollers 220 for guiding the paper to be smoothly transmitted in the device and ensuring that the paper maintains the correct position and tension during the coating process. The coating mechanism 300 is mounted on one side of the supporting roller 210 and includes a supply box 310 and a coating roller 320 arranged on the supply box 310. The supply box 310 is used to store the coating liquid, and the coating roller 320 uniformly coats the coating liquid on the paper. The scraper mechanism 400 is mounted on one side of the coating mechanism 300 and in contact with the paper, and includes a supporting seat 410 and a scraper 420 arranged on the supporting seat 410. The scraper 420 is used to remove the excess coating liquid on the coating roller 320, ensuring the coating quality, and at the same time, it is in contact with the edge of the paper that is not coated. The lubricating liquid spraying mechanism 500 is mounted on the other side of the coating mechanism 300 and at the edge of the supporting roller 210, and is used to spray the lubricating liquid on the edge of the paper. The lubricating liquid is used to protect the scraper 420, so that it can "float" on the lubricating oil and be in contact with the lubricating oil, thereby avoiding direct contact with the dry paper without coating liquid and reducing wear. The lubricating liquid here can be composed of water and substances dissolved therein, such as carboxymethyl cellulose or starch, which do not affect the performance of ordinary coating liquid.

[0058] By spraying the lubricating liquid on the edge of the paper that is not coated, the contact between the scraper 420 and the paper changes from dry friction to lubricated friction, significantly reducing the wear rate of the scraper 420, thereby prolonging the service life of the scraper 420 and reducing the need for frequent replacement of the scraper 420, further reducing the equipment maintenance cost and downtime. At the same time, the lubricating liquid is composed of water and harmless substances dissolved therein, which is harmless to the environment.

[0059] Embodiment 2:

[0060] The paper back coating device provided by the embodiments of the present application further includes the following technical features in addition to the above technical features.

[0061] AsFigure 2 The lubricating liquid spraying mechanism 500 comprises:

[0062] The mounting base 510 is arranged on the frame 100, and a first chamber 511 and a second chamber 512 storing lubricating oil are arranged in the mounting base 510;

[0063] The supply pipe 520 is arranged on the mounting base 510 and communicates with the first chamber 511 and the second chamber 512, and is used for supplying lubricating oil;

[0064] The spraying structure is arranged on the mounting base 510 and communicates with the chambers, and is used for spraying the lubricating oil in the chambers to the paper;

[0065] The supply pipe 520 has two supply pipes, and a metering pump 550 for controlling metering is arranged on each supply pipe 520.

[0066] In the embodiment, the mounting base 510 is arranged on the frame 100 as a support, and a first chamber 511 and a second chamber 512 storing lubricating oil are arranged in the mounting base 510. The two chambers can store different types of lubricating oil, and different lubricating oils can be sprayed according to requirements. The supply pipe 520 is arranged on the mounting base 510 and communicates with the first chamber 511 and the second chamber 512, and is used for conveying external lubricating oil to the first chamber 511 and the second chamber 512. In order to accurately control the supply amount of the lubricating oil, the metering pump 550 is arranged on each supply pipe 520. The metering pump 550 can accurately adjust the flow of the lubricating oil, and ensures the uniformity and stability of spraying. The spraying structure is arranged on the mounting base 510 and communicates with the chambers, and is used for atomizing and uniformly spraying the lubricating oil to the paper.

[0067] During the operation of the paper back coating equipment, when the paper passes through the lubricating liquid spraying mechanism 500, the lubricating oil in the chambers is conveyed to the spraying structure through the supply pipe 520 under the action of the metering pump 550. The spraying structure atomizes and uniformly sprays the lubricating oil to the edge of the paper which is not coated. Through the existence of the lubricating liquid, the doctor blade 420 avoids direct contact with the dry paper, and the abrasion is reduced.

[0068] Further, the spraying structure comprises:

[0069] The first spraying structure 530 is arranged on the mounting base 510 and connected with the first chamber 511;

[0070] The second spraying structure 540 is arranged on the mounting base 510 and communicates with the second chamber 512;

[0071] The second spraying structure 540 is located above the first spraying structure 530, and the second spraying structure 540 and the first spraying structure 530 are respectively used for spraying different lubricating oils.

[0072] The spraying structure is responsible for guiding the lubricating oil out of the chamber and spraying it evenly onto the paper, which includes a first spraying structure 530 and a second spraying structure 540, which are respectively connected to the first chamber 511 and the second chamber 512. The first spraying structure 530 is mounted on the mounting seat 510 and connected to the first chamber 511. The second spraying structure 540 is also mounted on the mounting seat 510 and located above the first spraying structure 530. By setting two spraying structures and connecting different chambers respectively, different lubricating liquids can be sprayed for different needs, improving the flexibility and diversity of the equipment.

[0073] Embodiment 3:

[0074] The paper back coating equipment provided by the embodiment of the present application further comprises the following technical features in addition to the above technical features.

[0075] As shown in Figure 2 The first spraying structure 530 comprises:

[0076] The support stand 531 is arranged on the support seat 410.

[0077] The first guide pipe 532 is arranged on the top of the support stand 531, one end of which is communicated with the first chamber 511, and the other end is provided with the first nozzle 533.

[0078] The first guide plate 534 is arranged on the support stand 531, the surface of which is provided with a positioning groove 535 for mounting the first nozzle 533, and the end away from the support stand 531 is arc-shaped and extends in the direction of the support roller 210.

[0079] The first guide plate 534 and the second spraying structure 540 form a first guide chamber 536 for spraying lubricating oil.

[0080] In the embodiment of the present application, the support stand 410 is provided with a support upright plate 531, which serves as the support base of the first spraying structure 530 and provides support to ensure the stability of the first spraying structure 530 during the operation of the equipment. The first guide pipe 532 is installed on the top of the support upright plate 531, one end of which is in communication with the first chamber 511, and is used to transport the lubricating oil in the chamber to the first nozzle 533, which is used to atomize and uniformly spray the lubricating oil on the paper. At the same time, the length and diameter of the first guide pipe 532 can be adjusted according to the flow rate of the lubricating oil and the spraying requirements. The first guide plate 534 is installed on the support upright plate 531, and the surface thereof is provided with a positioning groove 535 for installing the first nozzle 533, which is used to ensure that the first nozzle 533 is installed at a predetermined position to achieve accurate spraying effect. The end of the first guide plate 534 away from the support upright plate 531 is arc-shaped and extends towards the support roller 210, which helps to more uniformly guide the lubricating oil to the paper and reduces splashing and waste during spraying.

[0081] The first guide cavity 536 is the space formed between the first guide plate 534 and the second spraying structure 540, and when the lubricating oil is sprayed out of the first nozzle 533, it will enter the first guide cavity 536 and be guided to ensure that the lubricating oil can be accurately and uniformly sprayed on the edge of the paper, so as to ensure that the edge of the doctor blade 420 can be in contact with the lubricating oil.

[0082] Embodiment 4:

[0083] The paper back coating equipment provided by the embodiment of the present application further comprises the following technical features in addition to the above technical features.

[0084] As shown in Figure 2 The second spraying structure 540 comprises:

[0085] The limiting seat 541 is arranged on the first guide pipe 532, and the bottom of the limiting seat 541 is provided with an extension plate 542, and the first guide cavity 536 is located between the extension plate 542 and the first guide plate 534;

[0086] The second guide pipe 543 has one end in communication with the second chamber 512 and the other end penetrating through the limiting seat 541, and the second guide pipe 543 is provided with the second nozzle 544 at the end penetrating through the limiting seat 541;

[0087] The second guide plate 545 is arranged on the limiting seat 541 and located on both sides of the second nozzle 544;

[0088] The second guide plate 545 is arc-shaped and extends towards the support roller 210, and the second guide cavity 546 for spraying lubricating liquid is formed between the two second guide plates 545.

[0089] In the embodiment of the present application, the limiting seat 541 is installed on the first guide pipe 532 as the support of the second spraying structure 540, and the bottom is provided with an extension plate 542, which forms a first guide cavity 536 with the first guide plate 534, for guiding the lubricating oil sprayed by the first nozzle 533. One end of the second guide pipe 543 communicates with the second cavity 512 for conveying the lubricating oil in the cavity to the second nozzle 544, and the other end penetrates the limiting seat 541 and is provided with the second nozzle 544 at the end penetrating the limiting seat 541. The second nozzle 544 is used for atomizing and uniformly spraying the lubricating oil on the paper. The second guide plate 545 is installed on the limiting seat 541 and located on both sides of the second nozzle 544, and the two guide plates are installed on both sides of the second nozzle 544 in an up-down interval, are arc-shaped and extend to the direction of the supporting roller 210, can guide the lubricating oil more uniformly on the paper, and reduce the splashing and waste in the spraying process. At the same time, the second guide cavity 546 is formed between the two second guide plates 545, and when the lubricating oil is sprayed from the second nozzle 544, it will first enter the second guide cavity 546 and be guided by the second guide cavity 546. Through the installation of the first guide cavity 536 and the second guide cavity 546, it is helpful to reduce the splashing and waste of the lubricating oil and improve the utilization rate of the lubricating oil.

[0090] Further, the first nozzle 533 and the second nozzle 544 are each provided with a plurality of first nozzles 533 and second nozzles 544, which are uniformly distributed.

[0091] In the first spraying structure 530 and the second spraying structure 540, the first nozzle 533 and the second nozzle 544 are each provided with a plurality of nozzles, and the nozzles are uniformly distributed, which can uniformly and efficiently spray the lubricating oil, ensure that the edges of the paper can be completely sprayed, and the first nozzle 533 and the second nozzle 544 are at least provided with two.

[0092] It should be noted that, in the present document, the terms "comprises", "comprising", or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can also include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element proceeded by "comprises... a" does not, without more constraints, exclude the presence of additional identical elements in the process, method, article, or apparatus that comprises the element. Furthermore, it is to be understood that the method and apparatus of the present application can be carried out by someone other than the person named in the independent claims, and that the scope of the independent claims is not limited to the person named in the independent claims. In addition, it should be noted that the scope of the method and apparatus of the present application is not limited to performing the functions in the order shown or discussed, but can also include performing the functions in a substantially simultaneous manner or in a reverse order, for example, the described method can be performed in an order different from that described, and various steps can be added, omitted, or combined. In addition, features described with reference to certain examples can be combined in other examples.

[0093] The embodiments of the present application are described above with reference to the accompanying drawings, but the present application is not limited to the specific embodiments described above, which are merely illustrative and not restrictive, and a person of ordinary skill in the art can make many forms under the inspiration of the present application without departing from the purpose of the present application and the scope protected by the claims.

Claims

1. A paper back-coating apparatus comprising a frame (100), characterized in that: Also comprising: a guide structure (200) comprising a support roller (210) and a plurality of guide rollers (220) for guiding and supporting the paper; a coating mechanism (300) disposed on one side of the support roller (210) and comprising a supply box (310) and a coating roller (320) disposed on the supply box (310) for supplying and coating the paper with coating liquid; a doctor blade mechanism (400) disposed on one side of the coating mechanism (300) and in contact with the paper and comprising a support seat (410) and a doctor blade (420) disposed on the support seat (410); wherein a lubricating liquid spraying mechanism (500) is further included and disposed on the other side of the coating mechanism (300) and at the edge of the support roller (210) for spraying lubricating liquid onto the paper.

2. A paper backcoating apparatus as claimed in claim 1, characterized in that: The lubricating liquid spraying mechanism (500) comprises: a mounting seat (510) disposed on the rack (100) and having a first chamber (511) and a second chamber (512) storing lubricating oil inside; a supply pipe (520) disposed on the mounting seat (510) and in communication with the first chamber (511) and the second chamber (512) for providing lubricating oil; a spraying structure disposed on the mounting seat (510) and in communication with the chambers for spraying the lubricating oil in the chambers onto the paper; wherein the supply pipe (520) has two and each supply pipe (520) is provided with a metering pump (550) for controlling metering.

3. A paper backcoating apparatus as claimed in claim 2, wherein: The spraying structure comprises: a first spraying structure (530) disposed on the mounting seat (510) and connected with the first chamber (511); a second spraying structure (540) disposed on the mounting seat (510) and in communication with the second chamber (512); wherein the second spraying structure (540) is located above the first spraying structure (530), and the second spraying structure (540) and the first spraying structure (530) are respectively used for spraying different lubricating oils.

4. A paper backcoating apparatus as claimed in claim 3, wherein: The first spraying structure (530) comprises: a support vertical plate (531) disposed on the support seat (410); a first guide pipe (532) disposed on the top of the support vertical plate (531) and having one end in communication with the first chamber (511) and the other end provided with a first nozzle (533); a first guide plate (534) disposed on the support vertical plate (531) and having a positioning groove (535) for mounting the first nozzle (533) on its surface, and an end away from the support vertical plate (531) being arc-shaped and extending towards the support roller (210); wherein the first guide plate (534) and the second spraying structure (540) form a first guide chamber (536) for spraying lubricating liquid.

5. A paper backcoating apparatus as claimed in claim 4, wherein: The second spraying structure (540) comprises: a limiting seat (541) disposed on the first guide pipe (532) and having an extension plate (542) disposed on its bottom, and the first guide chamber (536) being located between the extension plate (542) and the first guide plate (534); A second guide pipe (543) has one end communicated with the second chamber (512) and the other end penetrating the limiting seat (541), and the second guide pipe has a second nozzle (544) at the end penetrating the limiting seat (541); A second guide plate (545) is arranged on the limiting seat (541) and located on both sides of the second nozzle (544); Wherein, the second guide plate (545) is arc-shaped and extends to the direction of the supporting roller (210), and the second guide plate (545) forms a second guide cavity (546) for spraying lubricating liquid between the two second guide plates (545).

6. A paper backcoating apparatus as claimed in claim 5, wherein: The first nozzle (533) and the second nozzle (544) are both provided with multiple nozzles, and the multiple first nozzles (533) and the multiple second nozzles (544) are uniformly distributed.

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