A positioning device for a double-sided printing machine

Abstract

This invention discloses a positioning device for a double-sided printing machine, comprising a pair of active conveyor rollers, a guide roller, a speed-regulating roller, and a pair of tail conveyor rollers. The speed-regulating roller is located between and below the guide roller and the pair of tail conveyor rollers. The pair of tail conveyor rollers includes a fixed conveyor roller and a movable conveyor roller. The speed-regulating roller is equipped with a ratchet, which engages with a pawl. The pawl is equipped with a first magnet. The movable conveyor roller is connected to a second magnet. Changes in the fabric conveying speed cause changes in the swaying amplitude of the pawl, changes in the distance between the first and second magnets, changes in the attraction force of the first magnet on the second magnet, changes in the gap between the movable and fixed conveyor rollers, and changes in the friction force of the pair of tail conveyor rollers on the fabric. This achieves the goal of straightening and tightening the fabric under both fast and slow speed conditions, providing conditions for improving the printing effect of the double-sided printing machine on the fabric.

Description

Technical Field

[0001] This invention relates to printing equipment, specifically to double-sided printing equipment. Background Technology

[0002] A double-sided printing machine includes a positioning device for positioning the fabric and a printing device for double-sided printing on the fabric. The positioning device positions the fabric while simultaneously inputting and outputting the fabric to the printing device. To ensure the quality of the double-sided printing, the fabric needs to be flat and in a stretched and taut state during double-sided printing. Summary of the Invention

[0003] The technical problem solved by this invention is: how to tighten the fabric in a positioning device for positioning fabric.

[0004] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a positioning device for a double-sided printing machine, comprising a pair of active conveying rollers, a guide roller, a speed regulating roller, and a pair of tail conveying rollers. The pair of active conveying rollers are located in front of the printing device, and the guide roller, the speed regulating roller, and the pair of tail conveying rollers are located behind the printing device. The speed regulating roller is located between the guide roller and the pair of tail conveying rollers and is lower than the speed regulating roller and the pair of tail conveying rollers. The pair of tail conveying rollers includes a fixed conveying roller and a movable conveying roller. The speed regulating roller is provided with a ratchet, which cooperates with a pawl. The pawl is provided with a first magnet. The movable conveying roller is connected to a second magnet, which is adjacent to the first magnet.

[0005] After passing through a pair of tail conveyor rollers, the fabric goes down through the speed regulating rollers and then up through the guide rollers before entering the printing device. A pair of active conveyor rollers transport the fabric forward as a traction mechanism for the fabric.

[0006] During the fabric conveying process, the fabric moves forward at varying speeds due to the different shapes of the printed patterns. Regardless of the speed, the fabric must always remain taut.

[0007] If the fabric is conveyed at a high speed, the upward force exerted by the fabric on the speed-regulating roller increases, and the friction between the speed-regulating roller and the fabric increases. The fabric between the pair of active conveying rollers and the speed-regulating roller is stretched and tightened. Because the speed-regulating roller operates at a high speed, the ratchet mounted on it operates at a high speed. The time between the pawl disengaging from one ratchet tooth and engaging with another ratchet tooth is short. That is, after disengaging from one ratchet tooth, the pawl swings back slightly under the action of its own torsion spring before immediately engaging with another ratchet tooth. Thus, the rapid rotation of the ratchet results in a smaller swing amplitude of the pawl. The smaller swing amplitude of the pawl results in a greater distance between the first and second magnets, a smaller attraction force between the first and second magnets, a larger gap between the active and fixed conveying rollers, and less friction between the pair of tail conveying rollers on the fabric. This allows the fabric to quickly pass through the pair of tail conveying rollers, accommodating the rapid conveying of the fabric.

[0008] If the fabric conveying speed slows down, the upward force of the fabric on the speed-regulating roller decreases, and the friction between the speed-regulating roller and the fabric decreases. Because the speed-regulating roller is slow, the ratchet mounted on it also moves slowly. The time it takes for the pawl to disengage from one ratchet tooth and then re-engage with another is longer; that is, after disengaging from one ratchet tooth, the pawl swings back a significant amplitude under the action of its own torsion spring before engaging with another ratchet tooth. Thus, the slow rotation of the ratchet causes the pawl's swing amplitude to increase. The larger swing amplitude of the pawl brings the distance between the first and second magnets closer, increasing the attraction of the first magnet to the second magnet. This pulls the movable conveyor roller downwards, reducing the gap between it and the fixed conveyor roller. The friction between the pair of tail conveyor rollers and the fabric increases, and the fabric between the pair of active conveyor rollers and the pair of tail conveyor rollers is straightened and tightened.

[0009] This invention can straighten and tighten fabrics under both fast and slow operating conditions, providing conditions for improving the printing effect of double-sided printing machines on fabrics. Attached Figure Description

[0010] The invention will be further described below with reference to the accompanying drawings:

[0011] Figure 1 This is a schematic diagram of a positioning device for a double-sided printing machine;

[0012] Figure 2 for Figure 1 Top view;

[0013] Figure 3 A schematic diagram of the fabric being conveyed by the positioning device.

[0014] Explanation of symbols in the diagram:

[0015] 20. Guide rollers;

[0016] 30. Speed ​​regulating roller; 31. Ratchet;

[0017] 40. A pair of tail conveyor rollers; 41. Fixed conveyor roller; 410. Fixed conveyor roller shaft; 42. Movable conveyor roller; 420. Movable conveyor roller shaft; 43. Movable conveyor roller bracket; 430. Vertical strip groove; 44. Upper semi-circular component; 45. Lower semi-circular component; 46. Upper spring; 47. Lower spring; 48. Upper rod; 480. Upper rod guide structure; 49. Second magnet;

[0018] 50. Pawl; 501. Support shaft; 51. First magnet; 52. Lower rod; 520. Lower rod guide structure; 53. Fixing block;

[0019] 60. Rack;

[0020] 70. Fabric. Detailed Implementation

[0021] Combination Figure 1 , Figure 2 A positioning device for a double-sided printing machine includes a pair of active conveyor rollers, a guide roller 20, a speed regulating roller 30, and a pair of tail conveyor rollers 40. The pair of active conveyor rollers are located in front of the printing device, while the guide roller, speed regulating roller, and pair of tail conveyor rollers are located behind the printing device. The speed regulating roller is located between the guide roller and the pair of tail conveyor rollers and is lower than the speed regulating roller and the pair of tail conveyor rollers. The pair of tail conveyor rollers includes a fixed conveyor roller 41 and a movable conveyor roller 42. The speed regulating roller is provided with a ratchet 31, which engages with a pawl 50. The pawl is provided with a first magnet 51. The movable conveyor roller is connected to a second magnet 49, which is adjacent to the first magnet.

[0022] During the fabric conveying process, the fabric moves forward at varying speeds due to the different shapes of the printed patterns. Regardless of the speed, the fabric must always remain taut.

[0023] If the fabric 70 is conveyed at a high speed, the upward force of the fabric on the speed-regulating roller 30 increases, and the friction between the speed-regulating roller 30 and the fabric 70 increases. The fabric 70 between the pair of active conveying rollers and the speed-regulating roller 30 is straightened and tightened. Because the speed-regulating roller 30 moves quickly, the ratchet 31 mounted on it also moves quickly. The time between the pawl 50 disengaging from one ratchet tooth and engaging with another is short; that is, after disengaging from one ratchet tooth, the pawl 50 swings back slightly under the action of its own torsion spring before immediately engaging with another ratchet tooth. Thus, the rapid rotation of the ratchet 31 results in a smaller swing amplitude of the pawl 50. The smaller swing amplitude of the pawl 50 results in a greater distance between the first magnet 51 and the second magnet 49, a smaller attraction force between the first magnet 51 and the second magnet 49, a larger gap between the active conveying roller 42 and the fixed conveying roller 41, and less friction between the pair of tail conveying rollers 40 and the fabric 70. This allows the fabric to quickly pass through the pair of tail conveying rollers 40, accommodating rapid fabric conveying.

[0024] If the conveying speed of fabric 70 slows down, the upward force of the fabric on the speed regulating roller 30 decreases, and the frictional force of the speed regulating roller 30 on the fabric decreases. Because the speed regulating roller 30 is slow, the ratchet 31 mounted on it also moves slowly. The time it takes for the pawl 50 to disengage from one ratchet tooth and then re-engage with another is longer. That is, after disengaging from one ratchet tooth, the pawl 50 swings back significantly under the action of its own torsion spring before engaging with another ratchet tooth. Thus, the slow rotation of the ratchet 31 increases the swing amplitude of the pawl 50. The larger swing amplitude of the pawl 50 brings the distance between the first magnet 51 and the second magnet 49 closer, increasing the attraction of the first magnet 51 to the second magnet 49. This pulls down the movable conveyor roller 42, reducing the gap between it and the fixed conveyor roller 41. The frictional force of the pair of tail conveyor rollers 40 on the fabric 70 increases, and the fabric between the pair of active conveyor rollers and the pair of tail conveyor rollers 40 is straightened and tightened.

[0025] The movable conveyor roller 42 is mounted on the movable conveyor roller bracket 43, which is mounted on the frame 60. The movable conveyor roller bracket has a vertical strip groove 430, and the movable conveyor roller shaft 420 fits into the vertical strip groove. When the attraction force of the first magnet 51 on the second magnet 49 increases, the movable conveyor roller 42 is pulled down, and the movable conveyor roller shaft 420 moves down along the vertical strip groove 430.

[0026] An upper semi-circular component 44 and a lower semi-circular component 45 are fitted into the vertical strip groove 430. An upper spring 46 is provided between the upper semi-circular component and the top of the vertical strip groove, and a lower spring 47 is provided between the lower semi-circular component and the bottom of the vertical strip groove. The movable conveyor roller 420 is fitted between the upper and lower semi-circular components. The upper and lower semi-circular components 44 and 45 clamp the movable roller 420. The arrangement of the upper spring 46 and lower spring 47 can make the lifting and lowering of the movable conveyor roller 420 smooth, avoiding impact on the fabric 70. Among them, the elastic force of the lower spring 47 is greater than that of the upper spring 46, and the movable conveyor roller 420 has an upward displacement tendency.

[0027] An upper rod 48 is connected to the movable conveyor roller 42. The upper rod is fitted into an upper rod guide structure 480, which is mounted on the frame 60. A second magnet 49 is installed at the bottom of the upper rod. The upper rod guide structure 480 guides the lifting and lowering of the upper rod 48. The upper rod guide structure can be a guide groove on the frame 60. A vertical magnet groove is provided on the frame, and the first magnet 51 and the second magnet 49 are fitted into the magnet groove and can move up and down along the magnet groove.

[0028] A lower rod 52 is hinged to the pawl 50. The lower rod is fitted in the lower rod guide structure 520, which is set on the frame 60. The first magnet 51 is installed at the top of the lower rod.

[0029] As an improvement, a fixed iron block 53 is provided between the first magnet 51 and the second magnet 49, and the fixed iron block is mounted on the frame 60. The first magnet 51 moves up and down, approaching or moving away from the fixed iron block 53, and the fixed iron block 53 becomes magnetic due to the first magnet 51. The pawl 50 swings rapidly, causing the first magnet 51 to swing rapidly, and the rapid swing of the first magnet keeps the magnetic force of the fixed iron block 53 at a stable value. In this way, the second magnet 49 will not exhibit the same swinging behavior as the first magnet 51, which is beneficial to the stability of the fabric 70 conveying.

[0030] The support shaft 501 for fixing the conveyor roller shaft 410 and the pawl 50 is mounted on the frame 60, which is the frame of a double-sided printing machine.

[0031] The above description is only a preferred embodiment of the present invention. For those skilled in the art, there will be changes in the specific implementation and application scope based on the ideas of the present invention. The content of this specification should not be construed as a limitation of the present invention.

Claims

1. A positioning device for a double-sided printing machine, comprising a pair of active conveyor rollers, a guide roller (20), a speed regulating roller (30), and a pair of tail conveyor rollers (40), wherein the pair of active conveyor rollers are located in front of the printing device, the guide roller, the speed regulating roller, and the pair of tail conveyor rollers are located behind the printing device, and the speed regulating roller is located between the guide roller and the pair of tail conveyor rollers and is lower than the speed regulating roller and the pair of tail conveyor rollers, characterized in that: A pair of tail conveyor rollers includes a fixed conveyor roller (41) and a movable conveyor roller (42). The speed-regulating roller is provided with a ratchet (31), which engages with a pawl (50). The pawl is provided with a first magnet (51). The movable conveyor roller is connected to a second magnet (49), which is adjacent to the first magnet.

2. The positioning device for a double-sided printing machine as described in claim 1, characterized in that: The movable conveyor roller (42) is mounted on the movable conveyor roller bracket (43), which is mounted on the frame (60). The movable conveyor roller bracket has a vertical strip groove (430), and the movable conveyor roller shaft (420) fits into the vertical strip groove.

3. The positioning device for a double-sided printing machine as described in claim 2, characterized in that: The vertical strip groove (430) is fitted with an upper semi-circular part (44) and a lower semi-circular part (45). An upper spring (46) is provided between the upper semi-circular part and the top of the vertical strip groove, and a lower spring (47) is provided between the lower semi-circular part and the bottom of the vertical strip groove. The movable conveying roller shaft (420) is fitted between the upper semi-circular part and the lower semi-circular part.

4. The positioning device for a double-sided printing machine as described in claim 1, characterized in that: An upper rod (48) is connected to the movable conveyor roller (42). The upper rod is fitted in the upper rod guide structure (480). The upper rod guide structure is set on the frame (60). The second magnet (49) is installed at the bottom of the upper rod.

5. The positioning device for a double-sided printing machine as described in claim 1, characterized in that: A lower rod (52) is hinged to the pawl (50), and the lower rod is fitted in the lower rod guide structure (520). The lower rod guide structure is set on the frame (60), and the first magnet (51) is installed at the top of the lower rod.

6. The positioning device for a double-sided printing machine as described in claim 1, characterized in that: A fixing block (53) is provided between the first magnet (51) and the second magnet (49), and the fixing block is set on the frame (60).

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