Rotary screen printing machine scraper device

Abstract

The present invention discloses a scraper device for a rotary screen printing machine to meet the complex requirements of the rotary screen printing machine for the scraper device. The present invention sets a first frame as a translation mechanism, sets a second frame and a third frame as a rotation mechanism, the third frame can drive the scraper assembly to rotate around the second rotating shaft, the second frame can drive the scraper assembly to rotate around the first rotating shaft as the center, and a fourth frame is set to fix the scraper assembly and drive it to move up and down. The screen frame is respectively provided with a push mechanism and a third rotating shaft on both sides of the central axis of the screen drum, and the push mechanism drives the screen drum to be lifted or dropped horizontally around the third rotating shaft. The beneficial effects of the present invention are: easy installation, the ability to accurately control the timing and displacement of the scraper movement and rotation, and ensure efficient and stable operation of the screen printing machine.

Description

Technical Field

[0001] The invention relates to the technical field of rotary screen printing machines, and in particular to a scraper device of a rotary screen printing machine. Background Art

[0002] The rotary screen printer is a device that performs high-speed printing on a wide range of materials such as cloth and paper. It consists of a screen printing plate and a scraper. The scraper is used to press out ink from the through holes formed on the surface of the cylindrical screen printing plate and transfer the pressed ink to the printed material. Usually, the method in which end rings as supporting members are installed at both ends of the cylindrical screen printing plate is called a rotary screen, and the scraper is installed inside the rotary screen.

[0003] The requirements for the scraper device of the rotary screen printing machine are relatively complex: (1) The printing pressure can be adjusted and the scraper printing pressure does not change when the screen roller and the impression roller are adjusted when the paper thickness changes; (2) The scraper angle can be adjusted and the scraper impression point and printing pressure do not change when the angle is adjusted; (3) The scraper can be disengaged and engaged and disengaged before the screen roller and later than the screen roller to avoid damage to the screen printing plate; (4) The scraper impression point can be adjusted forward and backward according to the different conditions of printing solid graphics and fine lines; (5) During normal printing, the scraper is slightly lifted before the tail of the paper reaches the scraper and dropped before the front of the paper reaches the scraper to avoid damage to the screen printing plate and ensure printing quality; (6) The scraper can be easily installed and removed from the cylindrical screen printing plate. The above requirements put forward high demands on the design of the scraper device of the rotary screen printing machine. Summary of the invention

[0004] The invention provides a scraper device of a rotary screen printing machine to meet the complex requirements of the rotary screen printing machine for the scraper device.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0006] A rotary screen printing machine scraper device is designed, comprising a screen cylinder and an impression cylinder arranged opposite to each other, the screen cylinder is mounted on a screen frame, the impression cylinder is mounted on a main frame, and a scraper assembly is arranged in the screen cylinder, wherein:

[0007] The scraper is connected with a translation mechanism, a rotation mechanism, and a lifting mechanism. The translation mechanism includes a first frame and a translation drive unit. The translation drive unit is used to drive the first frame to move horizontally.

[0008] The rotating mechanism includes a second frame, a third frame, a first rotating shaft, and a second rotating shaft. The first rotating shaft is located within a certain range above and below the horizontal plane of the embossing line of the screen roller and the embossing roller, for example, within a range of 50 mm above and below, and is preferably located on the horizontal plane of the embossing line of the screen roller and the embossing roller. The center line of the second rotating shaft coincides with the working tip edge line of the scraper. The second rotating shaft can rotate around the first rotating shaft. The second frame can drive the scraper assembly to rotate around the first rotating shaft as the center. The third frame can drive the scraper assembly to rotate around the second rotating shaft. The third frame is provided with an upper and lower linear drive mechanism and is connected to the fourth frame through a linear guide rail. The scraper assembly is fixed on the fourth frame, and the upper and lower linear drive mechanism can drive the scraper assembly to move up and down.

[0009] The present invention arranges four layers of racks on the outer sides of the screen racks on both sides of the screen printing plate of the rotary screen printing machine:

[0010] The first frame is slidably mounted on the screen frame by a linear moving mechanism such as a linear guide rail and is fixed to the screen frame by a linear drive mechanism such as a screw nut mechanism or a servo motor linear drive mechanism. It can be moved back and forth relative to the screen frame by the linear drive mechanism. The first frame is designed to adjust the front and rear position of the scraper stamping point.

[0011] The second frame is rotatably mounted on the first frame, and the rotation center axis is defined as the first rotation axis Z1. The first rotation axis Z1 is located near the horizontal plane of the printing line of the screen roller and the printing roller. One end of the second frame is fixedly connected to the screen printing plate device frame through a linear drive mechanism such as a cylinder and a limit mechanism or a servo motor linear drive mechanism. The linear drive mechanism can drive the second frame to rotate around the first rotation axis Z1 and fix it at a certain position. The rotation of the second frame around the first rotation axis Z1 is designed as a mechanism for adjusting the scraper clutch pressure and lifting the scraper as well as the printing pressure.

[0012] The third frame is rotatably mounted on the second frame, and the rotation center axis is defined as the second rotation axis Z2. The second rotation axis Z2 coincides with the sharp edge line of the scraper, and the trajectory of its rotation around the first rotation axis Z1 passes through the printing line of the screen roller and the printing roller. The third frame and the second frame are fixedly connected by a linear drive mechanism such as a screw nut mechanism or a servo motor linear drive mechanism. The linear drive mechanism can drive the third frame to rotate around the second rotation axis Z2. The rotation of the third frame around the second rotation axis Z2 is designed as an angle adjustment mechanism for the scraper.

[0013] The third frame is provided with a vertical part, and the fourth frame is slidably installed on the vertical part of the third frame by a linear moving mechanism such as a linear guide rail and is fixed to the third frame by a linear driving mechanism such as a cylinder and a limit mechanism or a servo motor linear driving mechanism. The fourth frame is provided with a mounting part for a scraper holder, and the scraper holder of the scraper is mounted on the fourth frames on both sides. After the scraper is installed, the working sharp edge line of the scraper coincides with the second rotating axis Z2, so that when the scraper angle is adjusted, the position of the working sharp edge line of the scraper will not be changed, that is, the printing point and printing pressure of the scraper will not be changed; the fourth frame on one side of the printing machine (generally the operating side) is detachably installed with a scraper loading and unloading mechanism above the scraper mounting part, and the scraper loading and unloading mechanism is provided with a movable long sliding rod, which can slide deep into the inside of the rolled silk screen printing plate and can also be pulled out outside the silk screen printing plate. The installation of the scraper is carried out as follows: first, the fourth frame is raised to the top of the third frame by the linear drive mechanism, and then the scraper loading and unloading mechanism is fixed on the fourth frame on one side, and the long slide bar is pulled out to the outside of the screen printing plate. At this time, the two ends of the scraper bracket (together with the scraper) are loosely connected to the long slide bar. At this position, the long slide bar together with the scraper bracket and the scraper are in a position where they can avoid the supporting sleeve and other components of the screen roller device and smoothly enter the internal space of the screen printing plate. Push the long slide bar to send the scraper bracket together with the scraper into the screen printing plate. At this time, loosen the loose connection between the scraper bracket and the long slide bar, and the scraper bracket falls to the scraper installation position of the fourth frame. Position and tighten the scraper bracket on the fourth frame on both sides, pull out the long slide bar, remove the scraper loading and unloading mechanism, drive the linear drive mechanism to drop the fourth frame to the bottom of the third frame, and the installation of the scraper is completed. The steps for removing the scraper are opposite to the installation steps.

[0014] A knife lifting mechanism is installed on the wire mesh frame, and the knife lifting mechanism is provided with a connecting rod. A rotatable support shaft is installed in the middle of the connecting rod, and the support shaft is fixed on the wire mesh frame. One end of the connecting rod is fixed to the wire mesh frame through a linear drive mechanism such as a cylinder and a limit mechanism or a servo motor linear drive mechanism. An impact bearing is installed on the other end of the connecting rod. The impact bearing can push the second frame to rotate and position around the first rotation axis Z1. The knife lifting action is achieved by driving the linear drive mechanism to drive the impact bearing on the connecting rod to push the second frame. In the closing position, there is a certain gap between the second frame and the impact bearing, and it should be ensured that there is still a gap when the scraper pressure is adjusted to the maximum, that is, the scraper lifting mechanism cannot affect the adjustment of the scraper pressure during closing; at the same time, when the scraper is lifted, the scraper working edge and the screen printing plate are just in contact or have a slight pressure state. This state ensures that the scraper does not damage the screen printing plate when passing through the tail edge of the paper and the gap of the printing roller during closing printing, and at the same time ensures that when the scraper is lifted, the ink inside the screen printing plate will not run from the back of the scraper to the front of the scraper in large quantities, and when the scraper falls, the ink can quickly gather between the scraper and the screen printing plate to achieve a stable printing state. In addition, it can also ensure that when the paper thickness is changed, the position distance between the scraper and the screen printing plate does not change after the scraper is lifted.

[0015] Furthermore, a pushing mechanism and a third rotating shaft are respectively arranged on both sides of the central axis of the wire mesh drum on the wire mesh frame. The pushing mechanism drives the wire mesh drum to lift or drop horizontally around the third rotating shaft. The pushing mechanism includes a support shaft, a cylinder installed on the support shaft, and a wire mesh drum clutch shaft installed on the wire mesh frame. The cylinder is connected to the wire mesh drum clutch shaft through a cylinder connecting rod.

[0016] Furthermore, it also includes a closing position adjustment unit, which includes a first top seat, a first frame, a first top pin, a first wedge block, a first nut wedge block, and a first screw rod. The first top seat is fixedly mounted on the main machine frame, and the first wedge block is movably mounted in the first frame. The first wedge block and the inclined surface of the first nut wedge block are in sliding contact, the first top pin is mounted on the first wedge block, the first screw rod and the first nut wedge block are connected by threads, and the first top seat limits the first top pin.

[0017] Furthermore, the translation driving unit includes a nut and a screw rod, the nut is connected to the first frame, and the rotating screw rod can drive the first frame to move horizontally through the nut.

[0018] Further, the second frame is rotatably connected to the first frame via a first rotating shaft, and the third frame is rotatably connected to the second frame via a second rotating shaft.

[0019] Furthermore, the second frame is connected with a limiting unit, which includes a second frame, a second push pin, a second wedge block, a second nut wedge block, and a second screw rod. The second frame is fixedly mounted on the wire mesh frame, the second push pin is fixedly mounted on the second wedge block, the second wedge block is movably mounted in the second frame, the second wedge block and the second nut wedge block are in sliding contact with each other on inclined surfaces, the second screw rod and the second nut wedge block are connected by threads, and the second push pin limits the second frame.

[0020] Furthermore, when the blade is not lifted, the minimum gap between the impact bearing and the second frame is limited to not affecting the adjustment of the scraper pressure by the second frame, and a limiting screw is provided on the side of the connecting rod to limit the connecting rod.

[0021] Furthermore, the portion where the second frame contacts the second ejector pin is arranged to be consistent with the surface curve of the embossing roller before and after the embossing point, and the portion where the second frame contacts the impact bearing is arranged to be consistent with the inner surface curve of the screen roller before and after the embossing point.

[0022] Furthermore, it also includes a scraper loading and unloading mechanism, which includes a slide seat and a long slide rod. The lower part of the long slide rod is used to carry the scraper assembly, and the slide seat can be installed on the fourth frame.

[0023] Compared with the prior art, the beneficial technical effects of the present invention are:

[0024] 1. The present invention can adjust the front and rear positions of the scraper impression point by horizontal movement of the first frame, adjust the printing pressure, clutch pressure and scraper lifting by rotating the second frame around the first rotation axis Z1, adjust the angle of the scraper by rotating the third frame around the second rotation axis Z2, complete the installation of the scraper by the fourth frame and cooperate with the first, second and third frames to complete the adjustment of the scraper during the printing process of the screen printing machine.

[0025] 2. The present invention sets a closing and pressing position adjustment unit between the screen cylinder and the impression cylinder, and uses a wedge to adjust the closing and pressing position to adapt to papers of different thicknesses. The closing and pressing action time is set by the electronic control system of the printing press, so that the closing and pressing action of the scraper is later than that of the screen cylinder, and the opening and closing action of the scraper is earlier than that of the screen cylinder.

[0026] 3. The present invention delivers the scraper assembly into the screen printing plate through the long slide bar, positions and fastens the scraper on the fourth frame on both sides, and then pulls out the long slide bar to complete the installation of the scraper, which is easy to operate.

[0027] 4. The present invention sets a blade lifting mechanism at the end of the second frame, and lifts the scraper when the notch of the impression roller and the tail of the printing paper arrive, so as to prevent the scraper from damaging the screen printing plate. When the scraper is lifted, it is in a state of just contacting with the screen printing plate or with slight pressure. This state ensures that the scraper does not damage the screen printing plate when passing through the edge of the tail of the paper and the notch of the impression roller during the combined printing. At the same time, it ensures that when the scraper is lifted, the ink inside the screen printing plate will not run from the back of the scraper to the front of the scraper in large quantities. When the scraper falls, the ink can quickly gather between the scraper and the screen printing plate to achieve a stable printing state. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a side view of the scraper device in the present invention.

[0029] Figure 2 for Figure 1 Cross-sectional view along the AA direction.

[0030] Figure 3 It is a schematic structural diagram of the screen roller clutch press in the present invention.

[0031] Figure 4 It is a schematic diagram of the position of the scraper during the combined printing in the present invention.

[0032] Figure 5 It is a schematic diagram of the position of loading and unloading the scraper in the present invention.

[0033] Figure 6 It is a schematic diagram of the state of the scraper during the combined printing in the present invention.

[0034] Figure 7 It is a schematic diagram of the state of the scraper when the printing is not in progress in the present invention.

[0035] In the figure, 100 main frame, 101a main frame, 101b main frame, 200 paper transfer roller, 300 impression roller, 301 impression roller bite, 400 screen roller unit, 401a screen frame, 401b screen frame, 402 screen roller, 402a screen printing plate, 402b end ring, 402c end ring, 403a support sleeve, 403b support sleeve, 500 scraper device, 501 first frame, 502 second frame, 503 third frame, 504 fourth frame, 505 scraper assembly, 505a scraper frame, 505b scraper support plate, 505c scraper pressure plate, 505d scraper, 506 linear guide rail, 507 nut, 508 lead screw, 509 adjustment hand wheel assembly one, 510 bearing, 511 pin shaft, 512 gland, 513 spacer, 514 spacer, 515 connecting block, 516 cylinder connecting rod, 517 cylinder, 518a support shaft, 518b support shaft, 519 second screw rod, 520 second screw nut wedge block, 521 second wedge block, 522 second top pin, 523 second frame, 524 adjusting hand wheel assembly 2, 525 screw rod, 526 screw nut, 527 support shaft, 528 universal shaft, 529 adjusting hand wheel assembly 3, 530 linear guide rail, 531 support plate, 532 cylinder, 533 cylinder connecting rod, 534 support shaft, 535 limit block, 536 scraper loading and unloading mechanism, 536a handle, 536b slide seat, 536c long slide rod, 536d handle, 536e handle connecting seat, 537 screw, 538 scraper fixing fixed screw, 539 lifting support shaft, 540 impact bearing, 541 connecting rod, 542 pin shaft, 543 pin shaft, 544 cylinder connecting rod, 545 cylinder, 546 support shaft, 547 limit screw, 548 pin shaft, 600 screen clutch and pressure mechanism, 601 third rotating shaft, 602 support, 603 screen cylinder clutch shaft, 604 push cylinder, 605 cylinder connecting rod, 606 push support shaft, 607 first screw rod, 608 first screw nut wedge block, 609 first wedge block, 610 first push pin, 611 first frame, 612 adjusting hand wheel assembly four, 613 first top seat, 701 single sheet of paper, Z1 first rotating shaft, Z2 second rotating shaft, Z2h scraper angle adjustment shaft pressure position, Z2l scraper angle adjustment shaft pressure position, Z2 tThe lifting position of the scraper angle adjustment shaft, Z3The support shaft of the screen roller device, Z4The clutch shaft of the screen roller, Z4hThe closing position of the clutch shaft of the screen roller, Z4lThe disengaging position of the clutch shaft of the screen roller, PThe horizontal plane of the screen roller and the impression roller, DlhThe clutch pressure and lifting position trajectory of the scraper, SlhThe position trajectory of the clutch pressure of the screen roller, ShThe closing position of the screen roller, SlThe disengaging position of the screen roller, QThe rolling surface notch of the impression roller, HThe lifting distance of the scraper when loading and unloading the scraper, CThe adjustment angle of the scraper, HDhThe closing distance of the scraper, HDlThe disengaging distance of the scraper, HSlThe disengaging distance of the screen, dpsThe distance between the outer surface of the screen printing plate and the paper, dpThe thickness of the paper, dsThe thickness of the screen, LThe printing working circumference,lpw is the distance between the end of the lifting knife and the end of the paper, lqt is the distance between the end of the lifting knife and the edge of the notch on the roller surface, lpt is the distance between the end of the knife drop and the start line of the paper printing, t is the gap between the lifting knife bearing and the second frame, X1 is the pressure release angle of the screen roller, and X2 is the pressure release angle of the scraper. DETAILED DESCRIPTION

[0036] The screen printing plate of a rotary screen printer is a cylindrical body formed of thin fabric or thin plate, on which small holes corresponding to the pattern are etched. The printing work is completed by relying on a scraper device to squeeze the ink set inside the screen printing plate from the small holes corresponding to the pattern on the screen printing plate onto a substrate such as paper.

[0037] The scraper angle, pressure, and front and rear positions of the embossing point need to be adjusted according to the paper thickness, paper size, ink, screen printing plate thickness, and printed pattern content. The scraper's clutch pressure setting also needs to be coordinated with the screen roller's clutch pressure. (1) When the screen roller clutches and presses, the screen printing plate moves a large distance, and the scraper cannot damage the screen printing. Therefore, the scraper's closing action should be later than the screen roller's closing action, and the scraper's separation action should be earlier than the screen roller's separation action. (2) The circumferential surface of the impression roller of the single-sheet rotary screen printing machine, which serves as the printing roller, is not continuous, and a notch is required to install the paper-gripping teeth. During the printing process, when the notch of the rotating screen roller and the impression roller are opposite, the scraper's pressure on the screen printing plate is no longer supported. If no measures are taken, the scraper will damage the screen printing plate. The scraper needs to be lifted before the notch of the impression roller arrives, and the scraper needs to be lowered after the notch passes and before the paper arrives. (3) Since it is necessary to have a gap between the scraper and the screen printing plate, the scraper needs to be lifted before the notch of the impression roller arrives, and the scraper needs to be lowered after the notch passes and before the paper arrives. A certain amount of ink accumulation is formed to ensure the printing quality. Therefore, lifting the scraper is different from lifting the pressure. The scraper should be slightly lifted until the sharp edge of the scraper is in slight contact or pressure with the inner wall of the screen printing plate to avoid damaging the printing plate while preventing all the ink between the scraper and the screen printing plate from moving from under the scraper to in front of the scraper so that the ink can be quickly gathered when the scraper falls to ensure the quality of printing; (4) Similar to the notch of the impression roller, when the printing paper is thicker, the step between the tail of the paper and the impression roller will also cause the scraper to damage the screen printing plate. It is also necessary to lift the scraper before the tail of the paper moves to the scraper; (5) The screen roller is in the shape of a long cylinder. It is more difficult to install a longer scraper, which requires a certain mechanism.

[0038] It can be seen that the scraper device of the rotary screen printing machine is complex and precise. The specific implementation of the present invention is described below in conjunction with the drawings and embodiments. However, the following embodiments are only used to illustrate the present invention in detail and do not limit the scope of the present invention in any way.

[0039] Embodiment 1: A rotary screen printing machine scraper device, see Figure 1 and Figure 2The rotating screen cylinder unit 400 is installed on the main frame 100 through the cylinder clutch unit 600, and the screen cylinder 402 is set above the impression cylinder 300, and the two rotate to roll for printing. A third rotating shaft 601 is fixedly installed on one side of the screen cylinder 402 of the rotating screen cylinder unit 400 and the screen frames 401a and 401b, and supports 602 are fixedly installed on the main frames 101a and 101b respectively. The two ends of the third rotating shaft 601 and the supports 602 on both sides are rotatably fixed, and the rotating screen cylinder unit 400 can rotate around the third rotating shaft 601. The center line of the third rotating shaft 601 is defined as the support axis Z3 of the screen cylinder device.The other side of the screen roller 402 on the rotating screen roller unit 400 and the screen frames 401a and 401b are fixedly installed with a screen roller clutch shaft 603, and the main frame 101a and 101b are respectively fixedly installed with a push support shaft 606, and the push support shaft 606 is respectively installed with a push cylinder 604, and the push cylinder 604 is connected and fixed to the screen roller clutch shaft 603 through a cylinder connecting rod 605. The center line of the screen roller clutch shaft 603 is defined as the screen roller clutch rotating shaft Z4. Through the off-pressure signal of the rotary screen printing machine, the push cylinder 604 pushes the screen roller clutch shaft 603 together with the screen roller unit 400 to wind the wire. The support shaft Z3 of the screen cylinder device rotates upward, and the screen cylinder 402 moves upward away from the impression cylinder 300, completing the depressing of the screen cylinder. The screen cylinder is in the depressing position S1, which is also the position for installing and maintaining the screen cylinder 402. Through the closing pressure signal of the rotary screen printing press, the push cylinder 604 pushes the shaft 603 together with the rotary screen cylinder unit 400 to rotate downward around the support shaft Z3 of the screen cylinder device, and the screen cylinder 402 moves downward toward the impression cylinder 300, completing the closing pressure of the screen cylinder. The screen cylinder 402 is in the closing pressure position Sh. Different from the depressing position, the closing pressure position of the screen cylinder 402 has precise requirements. It depends on the distance between the outer surface of the screen printing plate 402a and the surface of the paper required for press printing. This distance can be adjusted and controlled by adjusting the press position Sh of the screen roller 402. It is designed to be 0~0.5mm and can be adjusted. In addition, when the paper thickness changes, the press position Sh of the screen roller 402 is also adjusted to ensure the set roller printing distance. For this purpose, an adjustment and positioning link is provided. A first top seat 613 is provided on the main frame 101a, 101b, respectively, and a first top pin 610 is provided on the screen frame 401a, 401b, respectively. The first top pin 610 is installed on the first wedge block 609. The first wedge The block 609 and the first nut wedge block 608 are installed together in the first frame 611, and the first frame 611 is fixedly installed on the screen frame 401a, 401b. The inclined surfaces of the first wedge block 609 and the first nut wedge block 608 are connected, and the first nut wedge block 608 is threadedly connected to the first screw rod 607. One end of the first screw rod 607 is fixedly connected to the adjusting hand wheel assembly 412. The adjusting hand wheel is rotated, and then the first screw rod 607 is rotated to drive the first nut wedge block 608 to move forward and backward, and the first wedge block 609 can be pushed to drive the first top pin 610 to move up and down. The mutual distance between the rollers when they are pressed together can be determined by the limit of the first top seat 613. When the thickness dp of the paper 701 or (and) the thickness ds of the screen printing plate 402a changes significantly, the pressing distance dps can be changed by adjusting the hand wheel assembly 412.

[0040] Figure 3It is a schematic diagram of the clutch and pressure of the screen drum 402. The screen drum 402 rotates upward at an angle of X1 around the support axis Z3 of the screen drum device. The center of the screen drum moves along the arc Slh. The screen drum 402 moves from the closed pressure state Sh to the released pressure state Sl. The screen drum clutch shaft Z4 also moves from the closed pressure state Z4h to the released pressure state Z4l. The released pressure distance of the screen drum 402 is HSl.

[0041] like Figure 1 , Figure 2As shown, four layers of frames 501, 502, 503, and 504 are respectively arranged on the outside of the wire mesh frames 401a and 401b. The first frame 501 is connected to the wire mesh frames 401a and 401b through a linear guide rail 506. A nut 507 is fixed to the first frame 501. The nut 507 and the screw rod 508 are threadedly connected. The shaft end of the screw rod 508 is fixedly connected to the adjusting hand wheel assembly 509. The adjusting hand wheel is rotated to rotate the screw rod 508, and the first frame can be driven to move forward and backward through the nut 507. The second frame 502 and the first frame 501 are rotatably connected and are connected to each other through bearings 510 and 511. The pin shaft 511, the pressure cover 512, the spacer 513, the spacer 514, etc. are rotatably connected together, and the rotation center is defined as the first rotation axis Z1. The second frame is connected to the cylinder 517 and the cylinder connecting rod 516 through the connecting block 515, the pin shaft 548, and the cylinder 517. The cylinder 517 is fixedly connected to the wire mesh frames 401a and 401b through the support shafts 518a and 518b, respectively. The cylinder 517 can push the second frame 502 to rotate around the first frame 501 with the first rotation axis Z1 as the center; the third frame 503 and the second frame 502 are rotatably connected to each other through the bearing 510, the pin shaft 511, the pressure cover 512, the spacer 513, the spacer 514, etc. The sleeve 513, the spacer sleeve 514, etc. are rotatably connected together, and the rotation center is defined as the second rotation axis Z2. The third frame 503 is simultaneously connected to the second frame 502 through the support shaft 527, the nut 526, and the screw rod 525. The support shaft 527 is fixed to the second frame 502, the nut 526 is fixed to the third frame 503, the screw rod 525 is limitedly connected to the support shaft 527 and is threadedly connected to the nut 526, one end of the screw rod 525 is fixedly connected to the universal shaft 528 and the adjusting hand wheel assembly 3 529, and the adjusting hand wheel is rotated to rotate the screw rod 525 through the universal shaft 528, and the third frame 502 is driven through the nut 526. 03 rotates around the second frame 502 with the second rotation axis Z2 as the center; linear guides 530 and support plates 531 are vertically installed on the third frames 503 on both sides, and the fourth frame 504 is fixedly installed on the slide seat of the linear guides 530, and the cylinder 532 is fixed on the support plate 531. The cylinder 532 is fixedly connected with the support shaft 534 fixed on the fourth frame 504 through the cylinder connecting rod 533, and the cylinder 532 pushes the fourth frame 504 downward and is fixed at the limit block 535. The scraper assembly 505 is fixedly installed on the fourth frame 504 on both sides, and the working sharp edge of the scraper 505d after installation coincides with the second rotation axis Z2.

[0042] Through the above settings, such as Figure 1 , Figure 2 , Figure 4 As shown, the scraper device works like this:

[0043] Firstly, the rotating axes Z1 and Z2 are designed as follows: the first rotating axis Z1 is located on the horizontal plane of the embossing line between the screen cylinder 402 and the impression cylinder 300, and the second rotating axis Z2 can rotate around the first rotating axis Z1, and its rotation trajectory Dlh is designed to pass through the embossing line between the screen cylinder 402 and the impression cylinder 300, and the initial position of the second rotating axis Z2 is set to the position where the working sharp edge of the scraper 505d and the inner wall of the screen printing plate 402a just touch in the double-press printing state.

[0044] By the off-pressure signal of the rotary screen printing machine, the cylinder 517 pushes the second frame 502 to move upward, and the second frame 502 drives the third frame 503 and the fourth frame 504, and then drives the scraper assembly 505 to rotate upward at an angle X2 relative to the frame 501 with the first rotating shaft Z1 as the center to the off-pressure position. The off-pressure position does not need to be accurately set, and it can be the end of the cylinder's stroke. At this time, the second rotating shaft Z2 is at the off-pressure position Z2l, and the off-pressure distance of the scraper 505d is HDl; by the on-pressure signal of the rotary screen printing machine, the cylinder 517 pushes the second frame 502 to move downward, and the second frame 50 2 drives the third frame 503 and the fourth frame 504 to drive the scraper assembly 505 to rotate downward at an angle X3 relative to the frame 501 with the first rotating shaft Z1 as the center to the pressing position. The second rotating shaft Z2 is at the pressing position Z2h. The pressing distance of the scraper 505d is HDh. According to the pressing distance of the scraper 505d, the sharp edge of the scraper 505d should pass through the screen printing plate 402a and the paper 701 and be located below the paper. In fact, this size first eliminates the gap between the screen printing plate 402a and the paper 701, and then the deformation of the scraper 505d is produced. The pressure source for squeezing the ink is generated. The closing distance HDh only indicates the distance that the scraper 505d moves downward relative to the initial position during closing. Different from the off-press position, the closing position of the scraper assembly 505 has precise requirements. According to the hardness, working angle, ink, paper, etc. of the scraper 505d, the scraper 505d requires different working pressures. It precisely controls the limit of the second frame 502 during closing. The second frames 523 are fixedly provided on the screen frames 401a and 401b on both sides. The second wedge block 521 and the second wire wedge block 523 are provided in the second frame 523. 20. The second push pin 522 is installed on the second wedge block 521. The second wedge block 521 and the inclined surface of the second nut wedge block 520 are connected. The second nut wedge block 520 is threadedly connected with the second screw rod 519. One end of the second screw rod 519 is fixedly connected to the adjusting handwheel assembly 2 524. The adjusting handwheel is rotated, and then the second screw rod 519 is rotated to drive the second nut wedge block 520 to move forward and backward, which can push the second wedge block 521 to drive the second push pin 522 to move up and down. The second push pin 522 limits the downward position of the second frame. The adjusting handwheel assembly 2 524 can accurately adjust the pressing position of the scraper 505d. For the above-mentioned separation and closing pressure actions, the mechanisms on both sides of the machine should be kept synchronized, which is achieved by the electronic control program of the rotary screen printing machine. Moreover, there is a sequence requirement for the separation and closing pressure of the scraper and the separation and closing pressure of the screen roller. The closing pressure should be later than the closing time of the screen roller, and the separation pressure should be earlier than the separation time of the screen roller. Otherwise, the scraper will damage the screen printing plate, which is also achieved by the electronic control program of the rotary screen printing machine.

[0045] As can be concluded from the above analysis, during the printing process, the scraper needs to be lifted when passing through the tail of the paper and the gap of the printing roller to avoid damage to the screen printing plate while ensuring that the ink can be quickly gathered when the scraper falls to achieve stable quality printing. For this purpose, a scraper lifting mechanism is provided. A scraper lifting support shaft 539 is fixedly installed on the frames 402a and 402b of the screen printing plate device. A connecting rod 541 is rotatably installed on the scraper lifting support shaft 539. A pin shaft 542 and an impact bearing 540 are provided at one end of the connecting rod 541. The other end of the connecting rod is connected to a cylinder connecting rod 544 and a cylinder 545 through a pin shaft 543. The cylinder 54 The cylinder 545 is fixed to the frames 402a and 402b through the support shaft 546. The cylinder 545 can pull the connecting rod 541 to drive the impact bearing 540 to move and impact the second frame 502, thereby pushing the second frame 502 to rotate around the first rotation axis Z1 to realize the scraper lifting action. The scraper lifting is only required in the press printing state. Therefore, in the non-pressing state, the distance between the impact bearing 540 and the second frame 502 is relatively far, and the action stroke of the cylinder 545 will not cause the impact bearing 540 and the second frame 502 to contact. In the press state, the impact bearing 540 and the second frame 502 are not lifted when the scraper is not lifted. A certain gap t needs to be maintained between the two, and the gap should ensure that the bearing 540 and the second frame 502 do not contact when the pressure of the scraper 505d is adjusted to the maximum, that is, the blade lifting mechanism does not affect the pressure adjustment of the scraper. The gap t can be achieved by adjusting the stroke end position of the cylinder 545. When the rotary screen printing machine receives the blade lifting command during the combined printing, the cylinder 545 is activated, pulling the connecting rod 541 to drive the impact bearing 540 to move, and then pushing the second frame to rotate around the first rotation axis Z1 to lift the blade. The blade lifting position needs to be precisely controlled. For this purpose, the frames 402a and 402 A limit screw 547 is set on b to limit the knife lifting position of the connecting rod 541. The limit position can be adjusted by adjusting the limit screw 547. When the rotary screen printing machine receives a knife-dropping command, the cylinder 545 is actuated to push the connecting rod 541 to drive the impact bearing 540 to move in the opposite direction, and then the cylinder 517 drives the second frame 502 to rotate around the first rotation axis Z1 to drop the knife. After the scraper 505d falls, a gap t is maintained between the impact bearing 540 and the second frame 502 to prepare for the next knife-lifting action. The knife-lifting pressure of the cylinder 545 should be greater than and overcome the combined pressure of the cylinder 517.

[0046] By rotating the adjustment hand wheel assembly 509, and then rotating the screw rod 508, the first frame 501 can be driven to move forward and backward through the nut 507, so as to adjust the front and rear position of the printing point of the scraper 505a. The adjustment of the front and rear position of the scraper will not affect the scraper's pressing distance and the lifting position. However, since the surfaces of the impression roller 300 and the screen roller are curved, the scraper moves forward and backward so that the scraper's pressing point position drops and the inner wall of the screen printing plate at the lifting position moves upward. In order to keep the scraper pressure unchanged when closing the pressure and the gap with the inner wall of the screen printing plate unchanged when lifting the blade, the scraper's pressing distance and the lifting position should be increased accordingly. This can be achieved by changing The shape of the corresponding part of the second frame 502 contacted by the second ejector pin 522 and the shape of the corresponding part of the second frame 502 contacted by the impact bearing 540 are changed to be consistent with the surface curvature of the printing roller 300 before and after the printing point, and the shape of the corresponding part of the second frame 502 contacted by the impact bearing 540 is changed to be consistent with the inner surface curvature of the screen printing plate 402 before and after the printing point. Then, the adjustment of the front and rear positions of the scraper will correspondingly increase the scraper's pressing distance and raise the scraper lifting position, so that the scraper pressure remains unchanged and the scraper lifting effect is consistent.

[0047] Before and after printing, the scraper assembly 505 needs to be loaded or removed from the long cylindrical screen cylinder 402, which cannot be done by hand. For this purpose, a scraper loading and unloading mechanism is provided. Figure 1 and Figure 5As shown, the scraper loading and unloading mechanism 536 is installed above the scraper mounting part of the fourth frame 504 on one side, and the sliding seat 536b, the long sliding rod 536c, the handle 536d, the handle connecting seat 536e and other components are connected as an assembly that can be removed and installed from the fourth frame 504, and fixed by the handle 536a during installation. The scraper is installed as follows: when the screen roller 402 and the scraper 505 are in the de-pressed position, the cylinder 532 is manually commanded to move, and the fourth frame 504 is driven to move to the top through the cylinder connecting rod 533 and the support shaft 534, and the sliding seat 536b, the long sliding rod 536c, the handle 536d, the handle connecting seat 536e and other components are fixed to the fourth frame 504 with screws 536a, the long sliding rod 536c is pulled out to the outermost edge, and the scraper assembly 505 is hung under the long sliding rod 536c with screws 537. At this position, the long sliding rod 536c and the scraper assembly 505 are spatially located within the minimum inner diameter circular cross-section range of the support sleeves 403a, 403b and the end rings 402b, 402c, and will not interfere with the long sliding rod. The rod 536c and the scraper assembly 505 enter the interior of the screen cylinder 402, push the handle 536d, push the long slide rod 536c together with the scraper assembly 505 into the interior of the screen cylinder 402, manually position the scraper assembly on both sides, and fasten it to the fourth frame 504 on both sides with the scraper fixing screws 538, remove the screws 537, pull the long slide rod 536c out of the machine, loosen the handle 536a, take out the slide seat 536b, the long slide rod 536c, the handle 536d, the handle connecting seat 536e and other components from the fourth frame 504, manually command the cylinder 532 to move, and drop the fourth frame 504 together with the scraper assembly 505 to the limit block 535, completing the installation of the scraper, and the removal of the scraper is the opposite of the above steps.

[0048] Figure 6Schematic diagram of the operation status of the scraper during the combined printing process, wherein L is a printing working circumference, that is, one rotation of the screen roller 402, Q is the roller surface notch of the impression roller 300, the thickness of the paper 701 is dp, the thickness of the screen printing plate 402a is ds, the distance between the paper surface and the outer surface of the screen printing plate during the printing process is dps, and the position where the working tip of the scraper 505d just touches the inner wall of the screen roller is taken as the benchmark. This position is the lifting position of the scraper 505d, the scraper's separation distance is HDl, and the scraper's combined pressing distance is HDh. The combined pressing distance is essentially the distance that the scraper 505d moves downward, which first presses the thin wall of the screen printing plate 402a to the paper surface, thereby generating elastic deformation, and applying pressure to the screen printing plate 402a and the paper 701, which is the printing pressure. The scraper 505d should complete the lifting action at a certain distance lpw before the tail of the paper 701 and a certain distance lqt before the notch Q of the impression roller to avoid damage to the screen printing plate 402a, and should fall to the pressing position at a certain distance lpt before the printing plate head to stabilize the printing quality as soon as possible. It can be seen that the scraper 505d needs to be lifted before the tail of the paper and before the notch of the roller. The lifting command can be applied twice, but the implementation effect is that the lifting command is only executed once before the tail of the paper. In addition, due to the change in the length of the paper, the position of the tail of the paper is not fixed. The paper length information can be manually input into the human-machine interface of the rotary screen printing machine, which is all implemented by the electronic control program of the rotary screen printing machine.

[0049] Figure 7 Schematic diagram of the scraper state when it is off-press and not printing, where HS1 is the off-press distance of the screen, HD1 is the off-press distance of the scraper, and H is the distance the scraper is lifted when loading and unloading the scraper.

[0050] The adjustment of the position, pressure, angle and clutch pressure of the scraper device is essentially to solve the relationship between the scraper and the screen printing plate. Through the above design, the rotary screen scraper device of the invention has obvious advantages:

[0051] The first, second, third and fourth frames 501, 502, 503 and 504 of the scraper device are directly or indirectly fixed to the screen frames 401a and 401b of the rotating screen cylinder device, and the clutch pressure of the screen cylinder and the change of the closing pressure distance of the screen cylinder due to the change of paper thickness will not affect the positional relationship between the scraper 505d and the screen cylinder 402;

[0052] The first rotation axis Z1 is located on the horizontal plane of the nip line of the screen cylinder 402 and the impression cylinder 300, the working sharp edge of the scraper 505d coincides with the second rotation axis Z2, and the second rotation axis Z2 rotates around the first rotation axis Z1. The trajectory Dlh passes through the nip line of the screen cylinder 402 and the impression cylinder 300, so that when the printing pressure of the scraper 505d is adjusted, the change of the up and down position of the sharp edge of the scraper 505d has the least effect on the change of its front and rear position, and its front and rear impression points are basically not changed;

[0053] Adjustment of the angle of the scraper 505d does not affect the printing pressure and the nip point;

[0054] The position of the lifting blade is only related to the thickness of the screen printing plate 402a. The adjustment of the pressing position of the roller, the pressing position of the scraper, the angle of the scraper, etc. does not affect the position of the lifting blade.

[0055] The adjustment of the front and rear positions of the scraper after the improvement will not affect the pressing pressure of the scraper 505d and the distance between the scraper 505d and the inner wall of the screen printing plate 402a after the scraper is lifted.

[0056] The adjustment of the pressing position of the screen roller 402, the adjustment of the pressing position and pressure of the scraper 505d, the adjustment of the angle of the scraper 505d, the adjustment of the front and rear positions of the printing point of the scraper 505d, and the adjustment of the lifting position of the scraper, the adjustment of each link will not cause changes in other adjustment links, which makes the complex adjustment of the scraper device of the rotary screen printing machine simple and easy to control.

[0057] The present invention has been described in detail above with reference to the accompanying drawings and embodiments. However, those skilled in the art will appreciate that, without departing from the spirit of the present invention, the specific parameters in the above embodiments may be changed to form a plurality of specific embodiments, which are all within the common variation range of the present invention and will not be described in detail herein.

Claims

1. A rotary screen printing machine scraper device, comprising a screen cylinder and an impression cylinder arranged opposite to each other, wherein the screen cylinder is mounted on a screen frame, the impression cylinder is mounted on a main frame, a scraper assembly is arranged in the screen cylinder, and the scraper assembly comprises a scraper, characterized in that: The scraper assembly is connected with a translation mechanism, a rotation mechanism, and a lifting mechanism, wherein the translation mechanism comprises a first frame and a translation drive unit, and the translation drive unit is used to drive the first frame to move horizontally; The rotating mechanism includes a second frame, a third frame, a first rotating shaft, and a second rotating shaft. The center line of the second rotating shaft coincides with the working tip edge line of the scraper. The second rotating shaft can rotate around the first rotating shaft. The second frame can drive the scraper assembly to rotate around the first rotating shaft as the center. The third frame can drive the scraper assembly to rotate around the second rotating shaft. The third frame is provided with an upper and lower linear drive mechanism and is connected to the fourth frame through a linear guide rail. The scraper assembly is fixed on the fourth frame. The upper and lower linear drive mechanism can drive the scraper assembly to move up and down. The wire mesh frame is provided with a pushing mechanism and a third rotating shaft on both sides of the central axis of the wire mesh drum, respectively. The pushing mechanism drives the wire mesh drum to be lifted or lowered horizontally around the third rotating shaft. The pushing mechanism includes a pushing support shaft, a pushing cylinder installed on the pushing support shaft, and a wire mesh drum clutch shaft installed on the wire mesh frame. The pushing cylinder is connected to the wire mesh drum clutch shaft through a cylinder connecting rod. The second frame is connected to a limiting unit, and the limiting unit includes a second frame, a second top pin, a second wedge block, a second nut wedge block, and a second screw rod. The second frame is fixedly mounted on the wire mesh frame, the second top pin is fixedly mounted on the second wedge block, the second wedge block is movably mounted in the second frame, the second wedge block and the inclined surface of the second nut wedge block are in sliding contact, the second screw rod and the second nut wedge block are connected by threads, and the second top pin limits the second frame. One end of the second frame is connected to a knife lifting mechanism, and the knife lifting mechanism includes a knife lifting support shaft, on which a connecting rod is rotatably mounted, and one end of the connecting rod is provided with a pin shaft and an impact bearing, and the connecting rod can drive the impact bearing to move and impact the second frame to make it rotate around the first rotating shaft. When the blade is not lifted, the minimum gap between the impact bearing and the second frame is limited to not affecting the adjustment of the scraper pressure by the second frame, and a limiting screw is provided on the side of the connecting rod to limit the connecting rod.

2. The rotary screen printing machine scraper device according to claim 1, characterized in that: It also includes a pressing position adjustment unit, which includes a first frame, a first top seat, a first top pin, a first wedge block, a first nut wedge block, and a first screw rod. The first top seat is fixedly mounted on the main machine frame, the first frame is fixedly mounted on the wire mesh frame, the first wedge block is movably mounted in the first frame, the first wedge block and the inclined surface of the first nut wedge block are in sliding contact, the first top pin is mounted on the first wedge block, the first screw rod and the first nut wedge block are connected by threads, and the first top seat and the first top pin limit the pressing position of the wire mesh roller.

3. The rotary screen printing machine scraper device according to claim 1, characterized in that: The translation driving unit includes a nut and a lead screw. The nut is connected to an end of the first frame. The lead screw can be rotated to drive the first frame to move horizontally through the nut.

4. The scraper device of a rotary screen printing machine according to claim 1, characterized in that: The second frame is rotatably connected to the first frame via the first rotating shaft, and the third frame is rotatably connected to the second frame via the second rotating shaft.

5. The rotary screen printing machine scraper device according to claim 1, characterized in that: The portion where the second frame contacts the second ejector pin is set to be consistent with the surface curve of the impression roller before and after the impression point, and the portion where the second frame contacts the impact bearing is set to be consistent with the inner surface curve of the screen roller before and after the impression point.

6. The rotary screen printing machine scraper device according to claim 1, characterized in that: It also includes a scraper loading and unloading mechanism, which includes a slide seat and a long slide rod. The lower part of the long slide rod is used to carry the scraper assembly, and the slide seat can be installed on the fourth frame.

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