Paper biting mechanism and rotary screen printing machine

Abstract

The application discloses a paper biting tooth mechanism and a rotary screen printing machine to solve the technical problem that the existing paper biting tooth and the surface of the impression cylinder are prone to form steps and damage the screen printing plate. The paper biting tooth mechanism is arranged at the notch position of the impression cylinder and comprises a paper biting tooth piece and a tooth pad. The lower surface of the paper biting tooth piece is matched with the upper surface of the tooth pad, and the paper biting tooth piece is configured to be capable of linearly moving up and down. When the paper biting tooth piece clamps the paper, the back profile curved surface of the paper biting tooth piece and the upper surface of the paper attached to the surface of the impression cylinder form a smooth curved surface. The application also designs a driving mechanism for driving the paper biting tooth mechanism to move up and down. The paper biting tooth mechanism has the beneficial technical effects that the steps between the paper biting tooth and the surface of the impression cylinder are eliminated, the screen printing plate is protected, the adaptability of the rotary screen printing machine to the thickness of the paper is improved, and the product range of the rotary screen printing machine is expanded.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of printing machines, in particular to a paper biting tooth mechanism and a rotary screen printing machine. BACKGROUND

[0002] The paper conveying device (such as a paper feeding mechanism, a paper conveying cylinder, a paper collecting chain) or the printing device (such as a printing cylinder) of a conventional single sheet rotary printing machine is conveyed and printed by relying on the paper biting tooth to bite the paper. The paper biting tooth is installed on a paper biting tooth shaft, and the paper biting tooth is opened and closed by relying on the rotation of the paper biting tooth shaft to realize the functions of biting the paper and releasing the paper. The printing cylinder is a printing cylinder, and the printing cylinder is a printing cylinder. After the paper biting tooth bites the paper, the printing cylinder is pressed against the printing cylinder to complete the printing. The paper biting tooth is installed in the gap part of the printing cylinder body, and the printing cylinder (such as a rubber cylinder) also has a corresponding gap part. When printing by rolling, the gap part of the paper biting tooth corresponds to the gap part of the printing cylinder, as shown in FIG. 1. In addition to the requirement of the paper biting tooth to provide sufficient paper biting force in terms of function, the conventional printing machine does not have special restrictions on the size of the paper biting tooth. The size of the paper biting tooth basically exceeds the working outer surface of the printing cylinder. Figure 1

[0003] ​The requirements for the paper biting jaw of the impression cylinder of a rotary screen printing machine are much more complex. Since the screen printing plate is a cylinder formed by a thin fabric or a thin plate, the extrusion and impact from the outside and the inside will both cause damage to the screen printing plate. First, the screen cylinder is printed by the impression cylinder in a counter-rolling manner, which requires that the outer shape size of the paper biting jaw of the impression cylinder cannot exceed the working outer surface of the impression cylinder, otherwise the screen printing plate will be damaged by extrusion. Second, the screen printing is completed by moving the squeegee installed inside the screen cylinder downward to extrude the screen printing plate against the paper bitten by the impression cylinder, and the ink between the squeegee and the screen printing plate is extruded from the small holes corresponding to the pattern on the screen printing plate to the paper bitten by the impression cylinder to complete the printing. Since the paper has a certain thickness, a step will be formed between the paper tail and the surface of the cylinder. When the squeegee presses the screen printing plate against the paper to complete the printing and passes through the step of the paper tail, if no measures are taken, the squeegee will impact the screen printing plate, reducing the service life of the screen printing plate. Similarly or more seriously, when the screen cylinder and the impression cylinder are opposite to each other at the gap position, if no measures are taken, the squeegee will press the screen printing plate against the gap of the impression cylinder, causing damage to the screen printing plate. The conventional solution is to lift the squeegee before it passes through the paper tail or (and) before it passes through the gap of the impression cylinder, so that the inner surface of the squeegee and the screen printing plate are slightly in contact without pressure, avoiding damage to the screen printing plate by the squeegee. However, lifting the squeegee will cause new problems. After the squeegee is lifted, there is no printing pressure, and the ink accumulated between the squeegee and the screen printing plate will rotate from the back of the squeegee to the front of the squeegee with the screen printing plate, reducing the ink accumulated behind the squeegee. To ensure the quality of screen printing, it is necessary to provide stable and appropriate printing pressure by the squeegee, and sufficient ink should be accumulated behind the squeegee. Since the squeegee needs a certain distance to form stable and appropriate printing pressure after falling, and sufficient ink needs to be re-accumulated, if the squeegee falls on the working surface of the cylinder after passing through the gap of the impression cylinder, it means that the front edge of the paper cannot be printed stably, which will obviously sacrifice the adaptability of the printing layout. The correct solution should be to let the squeegee fall and form stable printing conditions before the front edge of the paper.

[0004] The above requirements for the paper biting jaw of the impression cylinder of a rotary screen printing machine are as follows: the outer shape size cannot be higher than the surface of the impression cylinder; stable support should be provided for the squeegee before the front edge of the paper. There are two common solutions: Figure 2 and 3As shown in patent EP-0723864A1, an active cover plate is arranged outside the paper biting teeth, which rotates and opens and closes like the paper biting teeth by cam and spring, opens before the paper biting teeth without affecting the opening of the paper biting teeth, closes later than the paper biting teeth without affecting the closing of the paper biting teeth, and the outer surface of the active cover plate forms the same outer profile as the outer surface of the impression cylinder after closing, so that the doctor blade can first fall on the active cover plate and then transition to the surface of the impression cylinder to form stable printing conditions before the front edge of the paper; another Figure 4 As shown in patent CN201310359285, the back surface of the paper biting tooth piece of the paper biting tooth of the impression cylinder is arranged as a curved surface consistent with the diameter of the impression cylinder, and the paper biting tooth forms the same outer profile as the impression cylinder after closing, and the doctor blade first falls on the back of the multiple paper biting tooth pieces arranged side by side and then transitions to the surface of the impression cylinder to form stable printing conditions before the front edge of the paper.

[0005] Both methods solve the problem of falling the doctor blade in advance before the front edge of the paper to form stable printing conditions, but whether the active cover plate or the paper biting tooth piece, they are all in rotary motion, see Figure 4 The paper biting pressure is not the same, the rear part always bites the paper first, the front part has smaller biting force, or even a gap, and this pressure difference is not obvious when the paper thickness is thin (≤0.15 mm), and the deformation of the paper eliminates the gap at the front end, but when the paper thickness reaches a certain thickness, the gap a between the front part of the paper biting tooth piece and the paper becomes larger or even exceeds the thickness of the thin paper, which causes new step collision damage to the screen printing plate during the running of the doctor blade, and this limits the adaptability of the rotary screen printing machine to the paper thickness. SUMMARY

[0006] The present application provides a paper biting tooth mechanism and a rotary screen printing machine to solve the technical problem that the existing paper biting tooth and the surface of the impression cylinder are prone to form steps and damage the screen printing plate.

[0007] To solve the above technical problems, the present application adopts the following technical solutions:

[0008] A paper biting tooth mechanism is designed and arranged at the notch part of the impression cylinder, which includes a paper biting tooth piece and a tooth pad, the lower surface of the paper biting tooth piece matches the upper surface of the tooth pad, and the two are used to clamp the paper, the paper biting tooth piece is configured to be able to move linearly up and down, and the back profile curved surface of the paper biting tooth piece and the upper surface of the paper attached to the surface of the impression cylinder form a smooth arc surface when clamping the paper.

[0009] Preferably, the paper biting tooth piece includes multiple pieces installed side by side on the paper biting tooth shaft, and the paper biting tooth piece and the paper biting tooth shaft move linearly up and down synchronously.

[0010] Preferably, the movable support shaft is installed in a linear sleeve, and the diameter of the linear sleeve matches the movable support shaft.

[0011] Preferably, the linear sleeve is a linear bearing fixed to the recessed part of the impression cylinder.

[0012] The application also discloses a rotary screen printing machine comprising the paper biting jaw mechanism and a driving mechanism for driving the paper biting jaw piece to perform linear motion.

[0013] Preferably, the driving mechanism comprises a swing arm fork, a rotating shaft and a cam, the swing arm fork comprises a central hole and first and second branches fixed to the central hole, the central hole is fixedly connected to the rotating shaft, the first branch comprises a U-shaped opening, the U-shaped opening is connected to the paper biting jaw shaft through a jaw bearing and a paper biting jaw piece, and the end of the second branch is provided with a swing arm bearing which is pressed against the cam.

[0014] Preferably, the swing arm fork further comprises a third branch, and the end of the third branch is connected to a pushing unit.

[0015] Preferably, the pushing unit comprises a spring rod, a spring and a spring support, the spring rod and the spring support are slidingly connected, the end of the spring rod is provided with a protrusion, and the spring is arranged between the protrusion and the spring support. The upper surface of the protrusion is a spherical surface, and the third branch is provided with a groove matched with the protrusion.

[0016] Compared with the prior art, the application has the beneficial technical effects that:

[0017] The application designs the rotary motion of the paper biting jaw as linear motion, fixes the paper biting jaw piece to the paper biting jaw shaft, and slidingly connects the paper biting jaw shaft and the impression cylinder body through a linear guide rail or a linear bearing. The paper biting jaw performs linear motion along the radial direction of the impression cylinder to realize the opening and closing of the paper biting jaw. Regardless of the thickness of the paper, the paper biting jaw piece bites the front and back width parts of the paper with a uniform biting pressure, the front end of the paper biting jaw piece does not tilt to form a gap with the paper, the back arc curve of the paper biting jaw piece and the surface curve of the paper attached to the surface of the impression cylinder smoothly transition, the impact of the tilted paper biting jaw piece on the screen printing plate is avoided, the screen printing plate is protected, the adaptability of the rotary screen printing machine to the thickness of the paper is improved, and the product range of the rotary screen printing machine is expanded. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 FIG. 1 is a schematic view of the positions of the paper biting jaw and the rubber blanket cylinder of a sheet-fed offset printing machine.

[0019] Figure 2Schematic diagram of the opening of the paper gripping teeth of the impression cylinder and the movable cover plate of the rotary screen printing machine.

[0020] Figure 3 Schematic diagram of the closing of the paper gripping teeth of the impression cylinder and the movable cover plate of the rotary screen printing machine.

[0021] Figure 4 Schematic diagram of the paper gripping teeth of the impression cylinder as a support for the doctor blade.

[0022] Figure 5 Analysis diagram of the gripping of the paper gripping teeth of the impression cylinder in the case of rotational movement.

[0023] Figure 6 Figure 5 Enlarged schematic diagram of part G.

[0024] Figure 7 Analysis diagram of the gripping of the paper gripping teeth of the impression cylinder in the case of linear movement.

[0025] Figure 8 Figure 7 Enlarged schematic diagram of part G'.

[0026] Figure 9 Schematic diagram of the opening of the paper gripping teeth of the invention.

[0027] Figure 10 Schematic diagram of the opening of the paper gripping teeth of the invention.

[0028] Figure 11 Example diagram of the impression cylinder of the rotary screen printing machine of the invention.

[0029] Figure 12 Figure 11 Sectional view in the direction of A-A.

[0030] Figure 13 Figure 11 Sectional view in the direction of B-B.

[0031] Figure 14 Figure 11 Sectional view in the direction of C-C.

[0032] Figure 15 Schematic diagram of the structure of the left swing arm fork.

[0033] Figure 16 Schematic diagram of the structure of the right swing arm fork.

[0034] Figure 17 Schematic diagram of the mechanism of the push unit of the invention.

[0035] ​​​​​01 printing cylinder, 01a printing cylinder body, 01a' printing cylinder outer surface profile line, 01b tooth pad, 01c paper biting jaw piece, 01d paper biting jaw axle, 01P printing cylinder gap, 02 rubber blanket cylinder, 02P rubber blanket cylinder gap, 03 paper, 04 rotary screen printing machine printing cylinder, 04a printing cylinder body, 04a' printing cylinder outer surface profile line, 04b tooth pad, 04c paper biting jaw piece, 04d paper biting jaw axle, 04e movable cover plate, 04f movable cover plate swing arm, 04g movable cover plate axle, 04h movable cover plate tooth opening swing arm, 04j movable cover plate tooth opening bearing, 04k movable cover plate tooth opening cam, 04P cylinder gap, 05 screen cylinder, 05a screen printing plate, 05b squeegee, 06 printing cylinder, 06a printing cylinder body, 06a' printing cylinder outer surface profile line, 06b tooth pad, 06c paper biting jaw piece, 06c' paper biting jaw piece back profile line, 06d paper biting jaw axle, 06e fixed cover plate, 06P printing cylinder gap, 07 screen cylinder, 07a screen printing plate, 07b squeegee, 08 printing cylinder, 08a printing cylinder body, 08a' printing cylinder outer surface profile line, 08b tooth pad, 08c paper biting jaw piece, 08c' paper biting jaw piece back profile line, 08d paper biting jaw axle, 08P printing cylinder gap, 09 screen cylinder, 09a screen printing plate, 09b squeegee, A paper biting jaw rotation angle, a paper biting jaw tip distance from paper distance, B paper biting jaw bite paper up and down movement distance, C paper biting jaw tooth opening movement distance, D paper biting jaw contact paper point, D' paper biting jaw contact paper surface, F ink, G enlarged range of schematic diagram, W paper biting jaw bite paper width, SL01 machine frame, SL02 machine frame, SL03 printing cylinder body, SL03P cylinder gap, SL04 paper biting jaw, SL04a paper biting jaw piece, SL05 paper biting jaw axle, SL06 tooth pad, SL07 movement support axle, SL08 linear bearing, SL09 tooth opening bearing, SL10 pressure cover, SL11 rotation axle, SL12 rotation axle support, SL13 support bearing, SL14 right swing arm yoke, SL15 swing arm bearing, SL16 cam, SL17 spring rod, SL18 spring, SL19 spring support, SL20 left swing arm yoke, SL21 first branch, SL22 second branch, SL23 third branch. DETAILED DESCRIPTION

[0036] The specific embodiments of the present application will be described below in conjunction with the drawings and examples, but the following examples are only used to illustrate the present application in detail, and do not limit the scope of the present application in any way.

[0037] Example 1: A paper biting jaw mechanism changes the paper biting jaw piece 01c from circular motion to linear motion. Specifically: see Figures 1 to 10 , wherein, Figure 1The figure shows the position relationship of the impression cylinder and the rubber blanket cylinder during printing, 01 is the impression cylinder, 02 is the rubber blanket cylinder, the paper biting jaw shaft 01d of the impression cylinder 01 is installed at the notch 01P of the impression cylinder body 01a, the paper biting jaw is installed on the paper biting jaw shaft 01d, the paper biting jaw piece 01c is closed together with the jaw pad 01b to bite the paper, at this time, the size of the paper biting jaw piece 01c exceeds the contour line 01a' of the outer surface of the impression cylinder, but during the printing of the impression cylinder 01 and the rubber blanket cylinder 02, the paper biting jaw piece 01c is at the notch 02P of the rubber blanket cylinder 02, so it will not interfere with the rubber blanket cylinder, but for the screen cylinder of the rotary screen printing machine, there is no notch 02P on the rubber blanket cylinder 02, so the protruding paper biting jaw piece 01c will collide with the screen cylinder, so this structure is not suitable for the rotary screen printing machine.

[0038] Therefore, the existing rotary screen printing machine has two improvements on the paper biting jaw mechanism shown in the figure. Figure 1 The first improvement is shown in the figure. Figure 2 And Figure 3 An active cover plate 04e is added, wherein, Figure 2 The paper biting jaw piece 04c and the active cover plate 04e are opened, Figure 3 The paper biting jaw piece 04c and the active cover plate 04e are closed, 04 is the impression cylinder, 05 is the screen cylinder, the paper biting jaw piece 04c and the active cover plate 04e are installed at the notch 04P of the impression cylinder body 04a, the paper biting jaw piece 04c rotates around the paper biting jaw shaft 04d, when closed, the paper biting jaw piece 04c and the jaw pad 04b together bite the paper, after the paper biting jaw is closed, the active cover plate 04e is also closed, the cam 04k drives the jaw opening bearing 04j, which drives the swing arm 04h, 04f, and then drives the active cover plate 04e to rotate around the active cover plate shaft 04g to cover the paper biting jaw piece 04c and abut against the impression cylinder body 04a, the back curved surface of the active cover plate 04e and the contour line 04a' of the outer surface of the impression cylinder become a curved surface, which provides the scraper 05b to fall in front of the paper at the front end and gather enough ink F between the screen printing plate 05a and form a stable and appropriate pressure to achieve good printing conditions. When the impression cylinder 04 receives and transmits the paper, the paper biting jaw piece 04c and the active cover plate 04e need to be opened, and the active cover plate 04e should be opened before the paper biting jaw to avoid interference.

[0039] The second improvement is shown in the figure. Figure 4The fixed cover plate 06e is added, wherein 06 is the impression cylinder, 07 is the screen cylinder, the paper biting mechanism is installed at the gap 06P of the impression cylinder body 06a, the paper biting piece 06c rotates around the paper biting shaft 06d, the paper biting piece 06c and the tooth pad 06b jointly bite the paper when closed, the fixed cover plate 06e protects most of the gap 06P and is provided with a comb-shaped gap at the paper biting position, which provides space when the paper biting piece is opened, the back curved surface of the fixed cover plate 06e and the back curved surface 06c' of the paper biting piece 06c form a curved surface coinciding with the contour line 06a' of the outer surface of the impression cylinder, so that the squeegee 07b can gather enough ink F in front of the paper and form a stable and suitable pressure, so as to achieve good printing conditions.

[0040] The existing impression cylinder paper biting mechanism is analyzed in the following Figure 5 and Figure 6 , Figure 6 is Figure 5 the enlarged view of G in FIG. 8, 03 is the paper, 08 is the impression cylinder, 09 is the screen cylinder, the paper biting mechanism is installed at the gap 08P of the impression cylinder body 08a, the paper biting piece 08c rotates around the paper biting shaft 08d, in the closed state without paper, the paper biting piece 08c is close to the upper plane of the tooth pad 08b, the back curved surface 08c' of the paper biting piece and the contour line 08a' of the outer surface of the impression cylinder form a common curved surface, when the paper biting piece 08c and the tooth pad 08b jointly bite the thicker paper 03, the paper biting piece 08c rotates an angle A around the paper biting shaft 08d relative to the state without paper, from Figure 6 The enlarged view shows that the paper biting piece 08c only contacts the paper 03 at the rear edge D of the biting width W, and a larger gap a is formed between the paper biting piece 08c and the paper 03 at the front edge of the biting width W, forming a step, when the squeegee 09b transitions to the paper 03 along the curved surface 08c', it will undoubtedly impact the screen printing plate 09a, reducing the service life of the screen printing plate 09a.

[0041] Based on the above reasons, the paper biting mechanism is provided, referring to Figure 7 and Figure 8 , Figure 8 is Figure 7In the enlarged view of section G, 03 is the paper, 08 is the impression cylinder, and 09 is the screen cylinder. The bite teeth are installed at the notch 08P of the impression cylinder body 08a. The bite tooth shaft 08d and the bite tooth piece 08c move linearly along the radial direction of the impression cylinder 08a (the direction of the double arrow in the figure). In the closed state without paper, the bite tooth piece 08c is close to the upper plane of the bite pad 08b. The back curved surface 08c' of the bite tooth piece 08c and the outer surface contour line 08a' of the impression cylinder 08a form a common curved surface. When the bite tooth piece 08c and the bite pad 08b are in the closed state, the back curved surface 08c' of the bite tooth piece 08c and the outer surface contour line 08a' of the impression cylinder 08a form a common curved surface. When the grippers 08b and 08c jointly bite the thicker paper 03, the grippers move upward a distance B compared to when there is no paper. The grippers 08c are in full contact with the paper 03 within the gripping width W. The back curved surface 08c' of the grippers 08c and the surface of the paper 03 attached to the impression cylinder body 08a form a common curved surface. This curved surface is higher than the original outer surface contour line 08a' of the impression cylinder by B, that is, the thickness of the paper. However, it is still a perfect common curved surface. The scraper can smoothly transition to the paper surface along the curved surface 08c' without impacting the screen printing plate 09a.

[0042] It should be noted that the bite tooth shaft 08d moves linearly along the radial direction of the impression cylinder 08a together with the bite tooth. The radial direction is not limited to passing through the center line of the impression cylinder, nor is it limited to being parallel to the center line connecting the impression cylinder 08 and the screen cylinder 09. Figure 9 and Figure 10 , Figure 9 The direction of movement is parallel to the center line between the impression cylinder 08 and the screen cylinder 09. Figure 10 The direction of movement and the center line of the impression cylinder 08 and the screen cylinder 09 are deflected by a certain angle. The above-mentioned paper bite mechanism greatly broadens the adaptability of the rotary screen printing machine to paper thickness and improves the life of the screen printing plate.

[0043] Example 2: A rotary screen printing machine, see Figures 11 to 17, the impression cylinder body SL03 is rotatably mounted on the two sides of the frame SL01 and SL02, the paper biting tooth SL04, the paper biting tooth shaft SL05 and the tooth pad SL06 are mounted at the gap SL03P of the impression cylinder body SL03, the paper biting tooth SL04 is mounted on the paper biting tooth shaft SL05, the paper biting tooth shaft SL05 and the two moving shafts SL07 on the left and right are fixedly connected, the two moving shafts SL07 and the linear bearing SL08 fixedly mounted at the gap SL03P are in sliding fit, the moving shaft SL07 can drive the paper biting tooth shaft SL05 and the paper biting tooth SL04 to move linearly up and down according to the linear position defined by the linear bearing SL08, the tooth pad SL06 is fixedly mounted on the impression cylinder body SL03, when the paper biting tooth SL04 moves up and down, the paper biting tooth piece SL04a can be in contact with the tooth pad SL06 and apply a certain pressure downward, and be separated from the tooth pad SL06 by a certain height upward, the up-and-down movement is the closing and opening action of the paper biting tooth SL04, which closes the paper and opens the paper, as analyzed above, when the paper biting tooth SL04 bites the paper, since it moves up and down, the back curved surface of the paper biting tooth piece SL04a and the surface of the paper attached to the impression cylinder body SL03 form a common curved surface, and the scraper can smoothly transition from the back curved surface of the paper biting tooth piece SL04a to the surface of the paper, without impacting the screen printing plate.

[0044] The up-and-down movement of the paper biting tooth SL04 is implemented through the following structure: at the gap SL03P, another rotating shaft SL11 is arranged adjacent to the side of the paper biting tooth shaft SL05, the rotating shaft SL11 is rotatably fixed at the gap SL03P by a plurality of rotating shaft supports SL12, the rotating shaft SL11 and the rotating shaft support SL12 are provided with the support bearing SL13, the two ends of the rotating shaft SL11 are respectively fixedly provided with the right swing arm yoke SL14 and the left swing arm yoke SL20, the circumferential positions of the two yokes are synchronous, and at the two side ends of the paper biting tooth shaft SL05, the split tooth bearing SL09 is fixedly mounted by the gland SL10, the two split tooth bearings SL09 are synchronously inserted into the first branch SL21 of the right swing arm yoke SL14 and the left swing arm yoke SL20, the right swing arm yoke SL14 and the left swing arm yoke SL20 and the linear bearing SL08 positionally limit the paper biting tooth shaft SL05 and the paper biting tooth SL04, and the spring support SL19 is fixedly mounted at the two side end faces of the impression cylinder body SL03, the spring rod SL17 is mounted on the spring support SL19, see Figure 17, spring rod SL17 and spring support SL19 sliding connection, spring rod SL17 top is equipped with a hemispherical protrusion, spring SL18 is arranged between the protrusion and the spring support, the third branch SL23 is equipped with a groove matched with the protrusion of spring rod SL17, spring rod SL17 is pressed on the third branch SL23 of right swing arm fork SL14 and left swing arm fork SL20 by spring SL18, second branch SL22 is arranged on right swing arm fork SL14, swing arm bearing SL15 is installed on the second branch SL22, at the same time, cam SL16 is fixedly installed on the rack SL01 of right swing arm fork SL14 side, swing arm bearing SL15 is pressed on cam SL16 by spring SL18. Cam SL16 is not arranged on the rack of left swing arm fork SL20 side, and left swing arm fork SL20 lacks second branch S22 and swing arm bearing SL15 compared with right swing arm fork SL14, and only supports.

[0045] When the impression cylinder rotates, swing arm bearing SL15 is pressed on the surface cam curve of cam SL16 by the spring pressure of spring SL18 and is driven to swing along with the cam curve to make right swing arm fork SL14 and left swing arm fork SL20 swing around rotation shaft SL11, the forks on both sides are synchronously driven to drive toothed shaft bearing SL09, and then drive paper biting tooth shaft SL05 and paper biting tooth SL04 to move up and down along the linear motion direction defined by linear bearing SL08. At the high point of the cam, paper biting tooth SL04 moves downward and contacts tooth pad SL06 to make a closing paper biting action, at the low point of the cam, paper biting tooth SL04 moves upward under the pressure of spring SL18 to open the paper, and the opening and closing positions of paper biting tooth SL04 can be accurately controlled by reasonably designing the surface curve of cam SL16.

[0046] The above describes the application in detail in combination with the drawings and examples, but those skilled in the art can understand that various specific parameters in the above examples can be changed to form multiple specific examples without departing from the purpose of the application, which are all within the common variation range of the application, and will not be described in detail.

Claims

1. A rotary screen printing machine characterized by, The paper biting mechanism is arranged at the gap part of the impression cylinder, and comprises a paper biting piece and a tooth pad, the lower surface of the paper biting piece and the upper surface of the tooth pad are matched, and the paper biting piece is configured to be linearly movable up and down. The rotary screen printing machine further comprises a driving mechanism for driving the paper biting piece to linearly move, the driving mechanism comprises a swing arm fork, a rotating shaft and a cam, the swing arm fork comprises a central hole and first and second branches fixed in the central hole, the central hole is fixedly connected to the rotating shaft, the first branch comprises a U-shaped opening, and a paper biting shaft bearing and a paper biting piece are connected through the U-shaped opening, and the end of the second branch is provided with a swing arm bearing which is pressed on the cam. The swing arm fork further comprises a third branch, the end of the third branch is connected with a pushing unit, the pushing unit comprises a spring rod, a spring and a spring support, the spring rod and the spring support are slidingly connected, the end of the spring rod is provided with a protrusion, the spring is arranged between the protrusion and the spring support, the upper surface of the protrusion is a spherical surface, and the third branch is provided with a groove matched with the protrusion.

2. The rotary screen printing machine according to claim 1, characterized in that The paper biting piece comprises a plurality of paper biting pieces which are installed side by side on the paper biting shaft and linearly move up and down synchronously.

3. The rotary screen printing machine according to claim 2, characterized in that The paper biting shaft is connected with a moving support shaft, and the moving support shaft is installed in a linear sleeve which has a diameter matched with the moving support shaft.

4. The rotary screen printing machine according to claim 3, characterized in that The linear sleeve is a linear bearing fixed at the gap part of the impression cylinder.

Images