Paper collecting and releasing constant tension device of printer

Abstract

A constant-tension device for paper winding and unwinding of a printer comprises a paper unwinding tension assembly and a paper winding tension assembly. The paper feeding tension assembly comprises two first fixing frames, a first swing frame is rotationally installed between the two first fixing frames, a first paper feeding roller is rotationally installed on the rear side portion of the first swing frame, a first balance weight roller is installed on the front side portion of the first swing frame, and a paper feeding sensor assembly is installed on the first fixing frame on the right side. The paper collecting tension assembly comprises two second fixing frames, a second swing frame is rotationally installed between the two second fixing frames, a second paper feeding roller is rotationally installed on the front side portion of the second swing frame, a second balance weight roller is installed on the rear side portion of the second swing frame, and a paper collecting sensor assembly is installed on the second fixing frame on the right side. According to the utility model, the paper stacking or tensioning condition at the paper collecting and releasing position in the printing process of the printer can be avoided, the paper is prevented from being folded or damaged due to too tight tension, the paper shortage signal can be detected in time, the design is scientific, and the structure is reasonable.

Description

Technical Field

[0001] The utility model relates to the field of printer equipment, in particular to a constant tension device for retracting and releasing paper of a printer. Background Art

[0002] When the printer is printing the medium, the rotation speed of the take-up roller and the unwinding roller is usually uniform, while the paper moves intermittently when passing through the printing platform. In this case, paper may be piled up or stretched at the take-up roller and the unwinding roller, causing the paper to be folded or damaged due to excessive tension. Moreover, as the printing process proceeds, the diameter of the roll on the take-up roller gradually increases. Therefore, the linear speed of the paper wound onto the take-up roller gradually increases, and the paper rewinding speed of the take-up roller gradually increases. At the same time, the diameter of the roll on the unwinding roller gradually decreases. Therefore, the linear speed of the paper released from the unwinding roller gradually decreases, and the paper releasing speed of the unwinding roller gradually decreases. This will cause the paper releasing speed to fail to keep up with the printing speed, and the printing speed to fail to keep up with the paper receiving speed, which will also cause the paper to be damaged due to excessive tension. Furthermore, when the paper on the unwinding roller has been released, the unwinding roller is still idling, and the paper shortage signal cannot be detected in time.

[0003] In order to solve the above problems, people have been seeking an ideal technical solution. Summary of the invention

[0004] The purpose of the utility model is to address the deficiencies of the prior art and thus provide a constant tension device for paper retracting and releasing in a printer. The utility model can avoid paper accumulation or tension at the paper retracting and releasing position during the printing process of the printer, prevent paper from being folded or damaged by being pulled too tight, and can also detect paper shortage signals in a timely manner. The design is scientific and the structure is reasonable.

[0005] In order to achieve the above-mentioned purpose, the technical scheme adopted by the utility model is as follows: a constant tension device for retracting and releasing paper of a printer comprises a paper releasing tension assembly and a paper receiving tension assembly, with the paper traveling direction as the front side, the paper releasing tension assembly is installed on the front lower side of the unwinding roller, and the paper receiving tension assembly is installed on the rear upper side of the receiving roller; the paper releasing tension assembly comprises two first fixed frames, the two first fixed frames are symmetrically installed on both sides of the printer frame and located on the front lower side of the unwinding roller, a first swinging frame is rotatably installed between the two first fixed frames, a first paper feeding roller located behind its rotating shaft and parallel to its rotating shaft is rotatably installed on the rear side of the first swinging frame, a first counterweight roller capable of moving forward and backward and adjusting is installed on the front side of the first swinging frame, the first counterweight roller is located in front of the rotating shaft of the first swinging frame and is parallel to the first paper feeding roller, the first paper feeding roller, the first counterweight roller and the first swinging frame constitute a lever mechanism with the rotating shaft of the first swinging frame as the fulcrum, the torque of the first paper feeding roller is greater than the torque of the first counterweight roller, and a paper releasing sensor assembly for detecting the paper releasing state is installed on the first fixed frame on the right side;

[0006] The paper receiving force assembly includes two second fixed frames, which are symmetrically mounted on both sides of the printer frame and located on the upper rear side of the winding roller. A second swing frame is rotatably mounted between the two second fixed frames. A second paper feeding roller located in front of and parallel to its rotating shaft is rotatably mounted on the front side of the second swing frame. A second counterweight roller capable of front and rear adjustable movement is mounted on the rear side of the second swing frame. The second counterweight roller is located behind the rotating shaft of the second swing frame and is parallel to the second paper feeding roller. The second paper feeding roller, the second counterweight roller and the second swing frame form a lever mechanism with the rotating shaft of the second swing frame as the fulcrum. The torque of the second paper feeding roller is greater than the torque of the second counterweight roller. A paper receiving sensor assembly for detecting the paper receiving state is mounted on the second fixed frame on the right side.

[0007] The paper is unwound from the front lower side of the unwinding roller and passes forward and downward around the lower side of the first paper feed roller. Then the paper enters the printing platform forward and upward. After coming out from the front side of the printing platform, the paper passes forward and downward around the front side of the second paper feed roller. Finally, the paper is wound onto the winding roller from the front lower side of the winding roller. The first paper feed roller and the second paper feed roller are always pressed on the paper and provide tension to the paper.

[0008] Based on the above, the first swing frame includes a first left connecting plate and a first right connecting plate, the first left connecting plate and the first right connecting plate have the same structure and are symmetrically arranged between the two first fixed frames, the first left connecting plate and the first right connecting plate are tilted and arranged with a height higher in the front and a height lower in the rear, a first swing beam is fixedly connected between the middle parts of the first left connecting plate and the first right connecting plate, a first rotating shaft is fixedly installed on the left middle part of the first left connecting plate and the right middle part of the first right connecting plate, the first rotating shaft on the left side is rotatably installed on the first fixed frame on the left side, and the first rotating shaft on the right side is rotatably installed on the first fixed frame on the right side, two ends of the first paper feeding roller are respectively rotatably installed on the rear edge part of the first left connecting plate and the rear edge part of the first right connecting plate, the front side part of the first left connecting plate and the front side part of the first right connecting plate are both provided with a first adjusting long hole in the front-to-back direction, the first counterweight roller is arranged between the front side part of the first left connecting plate and the front side part of the first right connecting plate, and two ends of the first counterweight roller are respectively fixedly connected to one of the first adjusting long holes on both sides by fasteners.

[0009] Based on the above, the paper release sensor assembly includes a speed-up paper release signal proximity switch, a paper shortage signal proximity switch and a slow-down paper release signal proximity switch. The rear side of the first fixing frame on the right side is fixedly connected with a first mounting plate which is parallel to the first right connecting plate and is located on the right side of the first right connecting plate. The first mounting plate is located on the rear side of the first rotating shaft. A second adjustment long hole is vertically opened on the rear upper part of the first mounting plate, a third adjustment long hole is vertically opened on the front upper part of the first mounting plate, and a fourth adjustment long hole is vertically opened on the lower middle part of the first mounting plate. The speed-up paper release signal proximity switch is fixedly installed on a certain position on the second adjustment long hole and higher than the rear side of the first right connecting plate through a fastener. The paper shortage signal proximity switch is fixedly installed on a certain position on the third adjustment long hole and higher than the rear side of the first right connecting plate through a fastener. The slow-down paper release signal proximity switch is fixedly installed on a certain position on the fourth adjustment long hole and lower than the rear side of the first right connecting plate through a fastener. When the first paper feeding roller is lifted upward, the first right connecting plate swings clockwise, and the speed-up paper release signal proximity switch detects the first right connecting plate before the paper shortage signal proximity switch.

[0010] Based on the above, the second swing frame includes a second left connecting plate and a second right connecting plate, the second left connecting plate and the second right connecting plate have the same structure and are symmetrically arranged between the two second fixed frames, the second left connecting plate and the second right connecting plate are both spoon-shaped bent plates, the spoon portion of the second left connecting plate and the second right connecting plate is in the front, and the spoon handle portion is in the back, the spoon portion of the second left connecting plate and the second right connecting plate has an open side facing downward and covers directly above the winding roller, the spoon handle portion of the second left connecting plate and the second right connecting plate is located at the rear and lower part of the winding roller, a second swing beam is fixedly connected between the middle portions of the second left connecting plate and the second right connecting plate, the middle portion of the left side of the second left connecting plate and the right side of the second right connecting plate A second rotating shaft is fixedly installed on the middle part of each side, the second rotating shaft on the left side is rotatably installed on the second fixed frame on the left side, and the second rotating shaft on the right side is rotatably installed on the second fixed frame on the right side, two ends of the second paper feeding roller are rotatably installed on the front edge of the spoon part of the second left connecting plate and the front edge of the spoon part of the second right connecting plate respectively, the rear side of the spoon handle part of the second left connecting plate and the rear side of the spoon handle part of the second right connecting plate are both provided with a fifth adjusting long hole in the front-to-back direction, the second counterweight roller is arranged between the rear side of the spoon handle part of the second left connecting plate and the rear side of the spoon handle part of the second right connecting plate, and the two ends of the second counterweight roller are fixedly connected to a certain point on the fifth adjusting long hole on both sides by fasteners respectively.

[0011] Based on the above, the paper collection sensor assembly includes a speed-up paper collection signal proximity switch and a slow-down paper collection signal proximity switch. The front side of the second fixed frame on the right is fixedly connected with a second mounting plate which is parallel to the second right connecting plate and located on the right side of the second right connecting plate. The second mounting plate is located on the front side of the second rotating shaft. A sixth adjustment long hole is vertically opened on the lower middle side of the second mounting plate, and a seventh adjustment long hole is vertically opened on the upper middle side of the second mounting plate. The speed-up paper collection signal proximity switch is fixedly installed on a certain position of the sixth adjustment long hole and is lower than the front side of the second right connecting plate through fasteners. The slow-down paper collection signal proximity switch is fixedly installed on a certain position of the seventh adjustment long hole and is higher than the front side of the second right connecting plate through fasteners.

[0012] The utility model has substantial characteristics and progress compared with the prior art. Specifically, the working principle of the utility model is as follows: the utility model can adjust the torque of the first counterweight roller and the second counterweight roller by adjusting the front and rear positions of the first counterweight roller and the second counterweight roller respectively according to the material of the paper, and then the tension applied by the first paper feed roller and the second paper feed roller on the paper can be adjusted to ensure appropriate tension. The specific operation is: adjusting the installation positions of the two ends of the first counterweight roller on the first adjustment long hole of the first left connecting plate and the first adjustment long hole of the first right connecting plate, and adjusting the installation positions of the two ends of the second counterweight roller on the fifth adjustment long hole of the second left connecting plate and the fifth adjustment long hole of the second right connecting plate; when a lot of paper is released from the unwinding position of the unwinding roller, the first paper feed roller will move down and always press on the paper, thereby driving the first swing frame to swing counterclockwise, and the first right connecting plate will swing counterclockwise, slowing down the paper release signal. When the proximity switch detects the first right connecting plate, it triggers the driving device of the unwinding roller to reduce the driving speed, slowing down When the printing process is in progress, the diameter of the roll on the unwinding roller gradually decreases, the paper feeding speed decreases, and the paper feeding speed cannot keep up with the printing speed, the paper length between the printing platform and the unwinding roller becomes smaller, which will cause the first paper feed roller to lift up, thereby driving the first swing frame to swing clockwise, and then the first right connecting plate will swing clockwise, accelerating the paper feeding signal proximity switch to detect the first right connecting plate, triggering the driving device of the unwinding roller to increase the driving speed, and accelerating the paper feeding speed of the unwinding roller. When the paper on the unwinding roller is finished, the first paper feed roller loses the support of the paper and will swing down at a certain speed. Due to inertia, the first paper feed roller drives the first swing frame to swing counterclockwise, so that the front side of the first right connecting plate swings upward across the vertical line and approaches the paper out signal proximity switch, and then the paper out signal proximity switch detects the first right connecting plate, triggering the printer paper out alarm signal, reminding the user to change the roll as soon as possible to continue printing.

[0013] When the paper is to be reeled in by the winding roller, the second paper feed roller will move downward and always press on the paper, thereby driving the second swing frame to swing clockwise, and the second right connecting plate will swing clockwise, speeding up the paper collection signal. When the proximity switch detects the second right connecting plate, it will trigger the driving device of the winding roller to increase the driving speed, thereby speeding up the paper collection speed of the winding roller. On the contrary, when the paper is to be reeled in by the winding roller, the diameter of the roll on the winding roller gradually increases with the progress of the printing process, the paper collection speed increases, and the printing speed cannot keep up with the paper collection speed, the paper length between the printing platform and the winding roller becomes smaller, which will cause the second paper feed roller to lift up, thereby driving the second swing frame to swing counterclockwise, and the second right connecting plate will swing counterclockwise, slowing down the paper collection signal. When the proximity switch detects the second right connecting plate, it will trigger the driving device of the winding roller to reduce the driving speed, thereby slowing down the paper collection speed of the winding roller.

[0014] Among them, the second left connecting plate and the second right connecting plate are both spoon-shaped bent plates. Such a shape can well adapt to the paper receiving space and contour of the winding roller, making the structure installed on the printer more compact and reasonable, with better swing space. Furthermore, the positions of the paper release signal proximity switch, paper out signal proximity switch, slow paper release signal proximity switch, speed up paper receiving signal proximity switch and slow paper receiving signal proximity switch can be easily adjusted and reasonably arranged according to actual conditions.

[0015] Through the above working principle, the utility model can avoid paper accumulation or tension at the paper receiving and releasing part during the printing process of the printer, prevent the paper from being folded or damaged by being pulled too tight, and can also detect paper shortage signals in time, with scientific design and reasonable structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a structural schematic diagram of the paper placing force assembly of the utility model.

[0017] Figure 2 It is a structural schematic diagram of the paper collection force assembly of the utility model.

[0018] In the figure: 1. first fixed frame; 2. first paper feed roller; 3. first counterweight roller; 4. second fixed frame; 5. second paper feed roller; 6. second counterweight roller; 7. first left connecting plate; 8. first right connecting plate; 9. first swinging beam; 10. first rotating shaft; 11. first adjusting long hole; 12. speed up paper feeding signal proximity switch; 13. paper shortage signal proximity switch; 14. slow down paper feeding signal proximity switch; 15. first mounting plate; 16. second adjusting long hole; 17. third adjusting long hole; 18. fourth adjusting long hole; 19. second left connecting plate; 20. second right connecting plate; 21. second swinging beam; 22. second rotating shaft; 23. fifth adjusting long hole; 24. speed up paper receiving signal proximity switch; 25. slow down paper receiving signal proximity switch; 26. second mounting plate; 27. sixth adjusting long hole; 28. seventh adjusting long hole. DETAILED DESCRIPTION

[0019] The technical solution of the utility model is further described in detail below through specific implementation methods.

[0020] like Figure 1 and Figure 2 As shown, the constant tension device for retracting and releasing paper of the printer comprises a paper releasing tension assembly and a paper receiving tension assembly. With the paper traveling direction as the front side, the paper releasing tension assembly is mounted on the front lower side of the unwinding roller, and the paper receiving tension assembly is mounted on the rear upper side of the receiving roller. The paper releasing tension assembly comprises two first fixed frames 1, which are symmetrically mounted on both sides of the printer frame and located on the front lower side of the unwinding roller. A first swing frame is rotatably mounted between the two first fixed frames 1. A first paper feeding roller 2 which is located behind and parallel to its rotating shaft is rotatably mounted on the rear side of the first swing frame. A first counterweight roller 3 which can be moved and adjusted forward and backward is mounted on the front side of the first swing frame. The first counterweight roller 3 is located in front of the rotating shaft of the first swing frame and is parallel to the first paper feeding roller 2. The first paper feeding roller 2, the first counterweight roller 3 and the first swing frame constitute a lever mechanism with the rotating shaft of the first swing frame as the fulcrum. The torque of the first paper feeding roller 2 is greater than the torque of the first counterweight roller 3. A paper releasing sensor assembly for detecting the paper releasing state is mounted on the first fixed frame 1 on the right side.

[0021] The paper receiving force assembly includes two second fixed frames 4, which are symmetrically installed on both sides of the printer frame and located on the upper rear side of the winding roller. A second swing frame is rotatably installed between the two second fixed frames 4. A second paper feeding roller 5 located in front of and parallel to its rotating shaft is rotatably installed on the front side of the second swing frame. A second counterweight roller 6 that can be moved forward and backward and adjusted is installed on the rear side of the second swing frame. The second counterweight roller 6 is located behind the rotating shaft of the second swing frame and is parallel to the second paper feeding roller 5. The second paper feeding roller 5, the second counterweight roller 6 and the second swing frame constitute a lever mechanism with the rotating shaft of the second swing frame as the fulcrum. The torque of the second paper feeding roller 5 is greater than the torque of the second counterweight roller 6. A paper receiving sensor assembly for detecting the paper receiving state is installed on the second fixed frame 4 on the right side;

[0022] The paper is unwound from the front lower side of the unwinding roller and passes forward and downward around the lower side of the first paper feed roller 2. Then the paper enters the printing platform forward and upward. After coming out from the front side of the printing platform, the paper passes forward and downward around the front side of the second paper feed roller 5. Finally, the paper is wound onto the winding roller from the front lower side of the winding roller. The first paper feed roller 2 and the second paper feed roller 5 are always pressed on the paper and provide tension to the paper.

[0023] The first swing frame includes a first left connecting plate 7 and a first right connecting plate 8. The first left connecting plate 7 and the first right connecting plate 8 have the same structure and are symmetrically arranged between the two first fixed frames 1. The first left connecting plate 7 and the first right connecting plate 8 are tilted so that they are higher in the front and lower in the back. A first swing beam 9 is fixedly connected between the middle parts of the first left connecting plate 7 and the first right connecting plate 8. A first rotating shaft 10 is fixedly installed on the middle part of the left side of the first left connecting plate 7 and the middle part of the right side of the first right connecting plate 8. The first rotating shaft 10 on the left side is rotatably installed on the first fixed frame 1 on the left side, and the first rotating shaft 10 on the right side is rotatably installed on the first fixed frame 1 on the left side. The first rotating shaft 10 on the side is rotatably mounted on the first fixed frame 1 on the right side, and the two ends of the first paper feeding roller 2 are rotatably mounted on the rear edge of the first left connecting plate 7 and the rear edge of the first right connecting plate 8 respectively. The front side of the first left connecting plate 7 and the front side of the first right connecting plate 8 are both provided with a first adjusting long hole 11 along the front-to-back direction, and the first counterweight roller 3 is arranged between the front side of the first left connecting plate 7 and the front side of the first right connecting plate 8. The two ends of the first counterweight roller 3 are fixedly connected to one of the first adjusting long holes 11 on both sides by fasteners.

[0024] The paper placing sensor assembly includes a speed-up paper placing signal proximity switch 12, a paper shortage signal proximity switch 13 and a slow-down paper placing signal proximity switch 14. The rear side of the first fixing frame 1 on the right side is fixedly connected with a first mounting plate 15 which is parallel to the first right connecting plate 8 and is located on the right side of the first right connecting plate 8. The first mounting plate 15 is located on the rear side of the first rotating shaft 10. A second adjustment long hole 16 is vertically opened at the upper rear part of the first mounting plate 15, a third adjustment long hole 17 is vertically opened at the upper front part of the first mounting plate 15, and a fourth adjustment long hole 18 is vertically opened at the lower middle part of the first mounting plate 15. The speed-up paper placing signal proximity switch 12, the paper shortage signal proximity switch 13 and the slow-down paper placing signal proximity switch 14 are fixedly connected to the rear side of the first fixing frame 1 on the right side. The first mounting plate 15 is parallel to the first right connecting plate 8 and is located on the right side of the first right connecting plate 8. The first mounting plate 15 is located on the rear side of the first rotating shaft 10. A second adjustment long hole 16 is vertically opened at the upper rear part of the first mounting plate 15, a third adjustment long hole 17 is vertically opened at the upper front part of the first mounting plate 15, and a fourth adjustment long hole 18 is vertically opened at the lower middle part of the first mounting plate 15. The proximity switch 12 is fixedly installed at a certain position on the second adjustment long hole 16 and higher than the rear side of the first right connecting plate 8 through fasteners. The paper out signal proximity switch 13 is fixedly installed at a certain position on the third adjustment long hole 17 and higher than the rear side of the first right connecting plate 8 through fasteners. The slow paper release signal proximity switch 14 is fixedly installed at a certain position on the fourth adjustment long hole 18 and lower than the rear side of the first right connecting plate 8 through fasteners. When the first paper feed roller 2 is lifted upward, the first right connecting plate 8 swings clockwise, and the speed-up paper release signal proximity switch 12 detects the first right connecting plate 8 before the paper out signal proximity switch 13.

[0025] The second swing frame includes a second left connecting plate 19 and a second right connecting plate 20. The second left connecting plate 19 and the second right connecting plate 20 have the same structure and are symmetrically arranged between the two second fixed frames 4. The second left connecting plate 19 and the second right connecting plate 20 are both spoon-shaped bent plates. The spoon portion of the second left connecting plate 19 and the second right connecting plate 20 is in the front and the spoon handle portion is in the back. The open side of the spoon portion of the second left connecting plate 19 and the second right connecting plate 20 faces downward and covers the top of the winding roller. The spoon handle portion of the second left connecting plate 19 and the second right connecting plate 20 is located at the rear and lower part of the winding roller. A second swing beam 21 is fixedly connected between the middle parts of the second left connecting plate 19 and the second right connecting plate 20. The middle part of the left side of the second left connecting plate 19 and the second right connecting plate 20 A second rotating shaft 22 is fixedly installed in the middle of the right side, the second rotating shaft 22 on the left side is rotatably installed on the second fixed frame 4 on the left side, and the second rotating shaft 22 on the right side is rotatably installed on the second fixed frame 4 on the right side. The two ends of the second paper feeding roller 5 are rotatably installed on the front edge of the spoon part of the second left connecting plate 19 and the front edge of the spoon part of the second right connecting plate 20 respectively. The rear side of the spoon handle part of the second left connecting plate 19 and the rear side of the spoon handle part of the second right connecting plate 20 are both provided with a fifth adjusting long hole 23 along the front-to-back direction. The second counterweight roller 6 is arranged between the rear side of the spoon handle part of the second left connecting plate 19 and the rear side of the spoon handle part of the second right connecting plate 20. The two ends of the second counterweight roller 6 are fixedly connected to a certain point on the fifth adjusting long hole 23 on both sides by fasteners.

[0026] The paper receiving sensor assembly includes a speed-up paper receiving signal proximity switch 24 and a slow-down paper receiving signal proximity switch 25. The front side of the second fixed frame 4 on the right is fixedly connected with a second mounting plate 26 which is parallel to the second right connecting plate 20 and located on the right side of the second right connecting plate 20. The second mounting plate 26 is located on the front side of the second rotating shaft 22. A sixth adjustment long hole 27 is vertically opened on the lower middle side of the second mounting plate 26, and a seventh adjustment long hole 28 is vertically opened on the upper middle side of the second mounting plate 26. The speed-up paper receiving signal proximity switch 24 is fixedly installed on a certain position of the sixth adjustment long hole 27 and is lower than the front side of the second right connecting plate 20 by fasteners. The slow-down paper receiving signal proximity switch 25 is fixedly installed on a certain position of the seventh adjustment long hole 28 and is higher than the front side of the second right connecting plate 20 by fasteners.

[0027] The fasteners are not shown in the figure, and the fasteners are common fastening bolts or other similar connecting parts.

[0028] The paper release signal proximity switch, paper shortage signal proximity switch 13, slow paper release signal proximity switch 14, speed up paper collection signal proximity switch 24 and slow paper collection signal proximity switch 25 are all conventional technologies and can be purchased on the market, and the specific structure and working principle are not repeated here.

[0029] The working principle of the utility model is as follows: the utility model can adjust the torque of the first counterweight roller 3 and the second counterweight roller 6 by adjusting the front and rear positions of the first counterweight roller 3 and the second counterweight roller 6 according to the material of the paper, and then adjust the tension applied by the first paper feed roller 2 and the second paper feed roller 5 on the paper to ensure that the tension is appropriate. The specific operation is: adjust the installation positions of the two ends of the first counterweight roller 3 on the first adjustment long hole 11 of the first left connecting plate 7 and the first adjustment long hole 11 of the first right connecting plate 8, and adjust the installation positions of the two ends of the second counterweight roller 6 on the fifth adjustment long hole 23 of the second left connecting plate 19 and the fifth adjustment long hole 23 of the second right connecting plate 20; when a lot of paper is released from the unwinding position of the unwinding roller, the first paper feed roller 2 will move down and always press on the paper, thereby driving the first swing frame to swing counterclockwise, and the first right connecting plate 8 will swing counterclockwise, slowing down the paper release signal. When the proximity switch 14 detects the first right connecting plate 8, it triggers the driving device of the unwinding roller to reduce the driving speed, slowing down the paper release of the unwinding roller. When the printing process is in progress, the diameter of the roll on the unwinding roller gradually decreases, the paper feeding speed decreases, and the paper feeding speed cannot keep up with the printing speed, the length of the paper between the printing platform and the unwinding roller becomes smaller, which will cause the first paper feed roller 2 to lift up, thereby driving the first swing frame to swing clockwise, and then the first right connecting plate 8 will swing clockwise, accelerating the paper feeding signal proximity switch 12 to detect the first right connecting plate 8, triggering the driving device of the unwinding roller to increase the driving speed, and accelerating the paper feeding speed of the unwinding roller. When the paper on the unwinding roller is finished, the first paper feed roller 2 loses the support of the paper and will swing down at a certain speed. Due to inertia, the first paper feed roller 2 drives the first swing frame to swing counterclockwise, so that the front side of the first right connecting plate 8 swings upward across the vertical line and approaches the paper out signal proximity switch 13, and then the paper out signal proximity switch 13 detects the first right connecting plate 8, and triggers the printer paper out alarm signal, reminding the user to change the roll as soon as possible to continue printing.

[0030] When the second right connecting plate 20 is detected, the driving device of the winding roller 20 is triggered to increase the driving speed, thereby accelerating the paper receiving speed of the winding roller. On the contrary, when there is less paper to be received at the winding position of the winding roller, or as the printing process proceeds, the diameter of the roll on the winding roller gradually increases, the paper receiving speed increases, and the printing speed cannot keep up with the paper receiving speed, the paper length between the printing platform and the winding roller becomes smaller, which will cause the second paper feeding roller 5 to be lifted upward, thereby driving the second swing frame to swing counterclockwise, and the second right connecting plate 20 is swung counterclockwise, and the slow paper receiving signal proximity switch 25 detects the second right connecting plate 20, thereby triggering the driving device of the winding roller to reduce the driving speed, thereby slowing down the paper receiving speed of the winding roller.

[0031] Among them, the second left connecting plate 19 and the second right connecting plate 20 are both spoon-shaped bending plates. Such a shape can be well adapted to the paper receiving space and contour of the winding roller, making the structure installed on the printer more compact and reasonable, and having a good swing space. Furthermore, the positions of the paper release signal proximity switch, the paper shortage signal proximity switch 13, the slow paper release signal proximity switch 14, the speed up paper receiving signal proximity switch 24 and the slow paper receiving signal proximity switch 25 can be conveniently adjusted and reasonably arranged according to actual conditions.

[0032] Through the above working principle, the utility model can avoid paper accumulation or tension at the paper receiving and releasing part during the printing process of the printer, prevent the paper from being folded or damaged by being pulled too tight, and can also detect paper shortage signals in time, with scientific design and reasonable structure.

[0033] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model rather than to limit it. Although the utility model has been described in detail with reference to the preferred embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the utility model can still be modified or some technical features can be replaced by equivalents without departing from the spirit of the technical solution of the utility model, which should be included in the scope of the technical solution for protection of the utility model.

Claims

1. The printer paper retracting and releasing constant tension device is characterized by: The paper unwinding roller is a paper unwinding roller, and the paper unwinding roller is a paper unwinding roller. The paper unwinding roller is a paper unwinding roller, and the paper unwinding roller is a paper unwinding roller. The paper unwinding roller is a paper unwinding roller, and the paper unwinding roller is a paper unwinding roller. The paper unwinding roller is a paper unwinding roller, and the paper unwinding roller is a paper unwinding roller. The paper unwinding roller is a paper unwinding roller, and the paper unwinding roller is a paper unwinding roller. The paper unwinding roller is a paper unwinding roller, and the paper unwinding roller is a paper unwinding roller. The paper unwinding roller is a paper unwinding roller, and the paper unwinding roller is a paper unwinding roller. The paper unwinding roller is a paper unwinding roller, and the paper unwinding roller is a paper unwinding roller. The paper receiving force assembly includes two second fixed frames, which are symmetrically mounted on both sides of the printer frame and located on the upper rear side of the winding roller. A second swing frame is rotatably mounted between the two second fixed frames. A second paper feeding roller located in front of and parallel to its rotating shaft is rotatably mounted on the front side of the second swing frame. A second counterweight roller capable of front and rear adjustable movement is mounted on the rear side of the second swing frame. The second counterweight roller is located behind the rotating shaft of the second swing frame and is parallel to the second paper feeding roller. The second paper feeding roller, the second counterweight roller and the second swing frame form a lever mechanism with the rotating shaft of the second swing frame as the fulcrum. The torque of the second paper feeding roller is greater than the torque of the second counterweight roller. A paper receiving sensor assembly for detecting the paper receiving state is mounted on the second fixed frame on the right side. The paper is unwound from the front lower side of the unwinding roller and passes forward and downward around the lower side of the first paper feed roller. Then the paper enters the printing platform forward and upward. After coming out from the front side of the printing platform, the paper passes forward and downward around the front side of the second paper feed roller. Finally, the paper is wound onto the winding roller from the front lower side of the winding roller. The first paper feed roller and the second paper feed roller are always pressed on the paper and provide tension to the paper.

2. The constant tension device for retracting and releasing paper of a printer according to claim 1, characterized in that: The first swing frame includes a first left connecting plate and a first right connecting plate, the first left connecting plate and the first right connecting plate having the same structure and being symmetrically arranged between the two first fixed frames, the first left connecting plate and the first right connecting plate being inclined and arranged with a higher front and a lower rear, a first swing beam being fixedly connected between the middle portions of the first left connecting plate and the first right connecting plate, a first rotating shaft being fixedly installed on the left middle portion of the first left connecting plate and the right middle portion of the first right connecting plate, the first rotating shaft on the left side being rotatably installed on the first fixed frame on the left side, and the first rotating shaft on the right side being rotatably installed on the first fixed frame on the right side, two ends of the first paper feeding roller being rotatably installed on the rear edge portion of the first left connecting plate and the rear edge portion of the first right connecting plate, the front side portion of the first left connecting plate and the front side portion of the first right connecting plate are both provided with a first adjusting long hole in the front-to-back direction, the first counterweight roller being arranged between the front side portion of the first left connecting plate and the front side portion of the first right connecting plate, and two ends of the first counterweight roller being fixedly connected to one of the first adjusting long holes on both sides by fasteners.

3. The constant tension device for retracting and releasing paper of a printer according to claim 2, characterized in that: The paper placing sensor assembly includes a speed-up paper placing signal proximity switch, a paper shortage signal proximity switch and a slow-down paper placing signal proximity switch. The rear side portion of the first fixing frame on the right side is fixedly connected with a first mounting plate which is parallel to the first right connecting plate and is located on the right side of the first right connecting plate. The first mounting plate is located on the rear side of the first rotating shaft. A second adjusting long hole is vertically opened on the rear upper portion of the first mounting plate, a third adjusting long hole is vertically opened on the front upper portion of the first mounting plate, and a fourth adjusting long hole is vertically opened on the middle lower side of the first mounting plate. The speed-up paper placing signal proximity switch is fixedly installed at a certain position on the second adjusting long hole and higher than the rear side portion of the first right connecting plate through a fastener. The paper shortage signal proximity switch is fixedly installed at a certain position on the third adjusting long hole and higher than the rear side portion of the first right connecting plate through a fastener. The slow-down paper placing signal proximity switch is fixedly installed at a certain position on the fourth adjusting long hole and lower than the rear side portion of the first right connecting plate through a fastener. When the first paper feeding roller is lifted upward, the first right connecting plate swings clockwise, and the speed-up paper placing signal proximity switch detects the first right connecting plate before the paper shortage signal proximity switch.

4. The constant tension device for retracting and releasing paper of a printer according to claim 1, characterized in that: The second swing frame includes a second left connecting plate and a second right connecting plate, the second left connecting plate and the second right connecting plate have the same structure and are symmetrically arranged between the two second fixed frames, the second left connecting plate and the second right connecting plate are both spoon-shaped bent plates, the spoon portion of the second left connecting plate and the second right connecting plate is in the front, and the spoon handle portion is in the back, the spoon portion of the second left connecting plate and the second right connecting plate has an open side facing downward and covers the top of the winding roller, the spoon handle portion of the second left connecting plate and the second right connecting plate is located at the rear and lower part of the winding roller, a second swing beam is fixedly connected between the middle portions of the second left connecting plate and the second right connecting plate, the middle portion of the left side of the second left connecting plate and the middle portion of the right side of the second right connecting plate Both are fixedly installed with a second shaft, the second shaft on the left side is rotatably installed on the second fixed frame on the left side, and the second shaft on the right side is rotatably installed on the second fixed frame on the right side, two ends of the second paper feeding roller are rotatably installed on the front edge of the spoon part of the second left connecting plate and the front edge of the spoon part of the second right connecting plate respectively, the rear side of the spoon handle part of the second left connecting plate and the rear side of the spoon handle part of the second right connecting plate are both provided with a fifth adjusting long hole along the front-to-back direction, the second counterweight roller is arranged between the rear side of the spoon handle part of the second left connecting plate and the rear side of the spoon handle part of the second right connecting plate, and the two ends of the second counterweight roller are fixedly connected to a certain point on the fifth adjusting long hole on both sides by fasteners.

5. The constant tension device for retracting and releasing paper of a printer according to claim 4, characterized in that: The paper receiving sensor assembly includes a speed-up paper receiving signal proximity switch and a slow-down paper receiving signal proximity switch. The front side of the second fixed frame on the right is fixedly connected with a second mounting plate which is parallel to the second right connecting plate and located on the right side of the second right connecting plate. The second mounting plate is located on the front side of the second rotating shaft. A sixth adjustment long hole is vertically opened on the lower middle side of the second mounting plate, and a seventh adjustment long hole is vertically opened on the upper middle side of the second mounting plate. The speed-up paper receiving signal proximity switch is fixedly installed at a certain position on the sixth adjustment long hole and is lower than the front side of the second right connecting plate through fasteners. The slow-down paper receiving signal proximity switch is fixedly installed at a certain position on the seventh adjustment long hole and is higher than the front side of the second right connecting plate through fasteners.

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