Printer core and printer

Abstract

The invention relates to the technical field of printers, and particularly discloses a printer core and a printer.The printer core comprises a rack, a swing arm, a first gear, a second gear and a third gear, the swing arm, the first gear, the second gear and the third gear are rotationally arranged on the rack, and the first gear is tightly matched with the swing arm to drive the swing arm to be switched between a first state and a second state; the second gear is meshed with the first gear, a one-way clutch structure is arranged between the second gear and the third gear and enables the second gear to drive the third gear to synchronously rotate in the first direction, in the first state, the swing arm is separated from the third gear, and in the second state, the swing arm is driven by the third gear to rotate synchronously. The swing arm abuts against the third gear to limit rotation of the third gear. When the scheme is applied to the printer, the first gear can be connected with the paper roller rotating shaft, and the third gear can be connected with the thermal transfer ribbon roller rotating shaft, so that the used thermal transfer ribbon cannot pass through the printing head again along with paper returning, and the printing effect is ensured.

Description

Technical Field

[0001] This invention relates to the field of printer technology, and more particularly to a printer mechanism and printer. Background Technology

[0002] In the field of thermal transfer printing technology, thermal transfer printers are widely used in many scenarios such as logistics label printing, product identification printing, and invoice printing due to their advantages such as clear printing and high durability. The core principle of thermal transfer printing is to heat the print head and accurately transfer the toner on the ribbon to the printing medium, thereby forming clear and durable text or images.

[0003] In actual use, due to unavoidable mechanical failures such as gear wear and loose drive belts, thermal transfer printers often encounter situations where too much paper is output, meaning the length of the paper output by the printer exceeds the actual printing requirements. When this happens and the paper needs to be retracted, the ribbon that has already partially passed through the printhead will move in the opposite direction as the paper retracts. However, when the ribbon that has already passed through the printhead for the first time passes through, some toner may be transferred to the paper due to the heat of the printhead. This affects the uniformity and tightness of the remaining toner adhesion. If such a ribbon passes through the printhead again, the toner cannot be transferred to the printing medium as evenly and completely as a brand new ribbon, resulting in poor print quality, such as blurry text or images, uneven colors, spots, or streaks, seriously affecting print quality. Summary of the Invention

[0004] This invention discloses a printer mechanism and a printer to solve the aforementioned technical problems existing in related technologies.

[0005] To solve the above problems, the present invention adopts the following technical solution: In a first aspect, this application provides a printer mechanism for use in a printer, comprising a frame and a swing arm rotatably mounted on the frame, a first gear, a second gear, and a third gear; wherein: The swing arm has a mounting groove, the first gear is fitted into the mounting groove, and the first gear is tightly engaged with the swing arm, so that the swing arm can rotate with the rotation of the first gear to switch between a first state and a second state. The second gear meshes with the first gear, and a one-way clutch structure is provided between the second gear and the third gear. When the second gear rotates in the first direction, the one-way clutch structure is configured to drive the third gear to rotate synchronously. In the first state, the swing arm is separated from the third gear, allowing the third gear to rotate with the rotation of the second gear. In the second state, the swing arm abuts against the third gear to restrict the rotation of the third gear.

[0006] Secondly, this application also provides a printer, the disclosed printer including the aforementioned printer mechanism.

[0007] The technical solution adopted in this invention can achieve the following beneficial effects: The printer mechanism and printer of the present invention have a first gear that can be connected to the paper roller shaft for transmission, and a third gear that can be coaxially connected to the ribbon roller shaft. The drive source drives the first gear to rotate in a second direction, and simultaneously drives the second gear and the third gear to rotate in a first direction. At this time, the swing arm is in a first state, and the paper roller shaft and the ribbon roller shaft rotate synchronously. During the paper feeding process, the ribbon is wound up synchronously for inking and printing. When the paper output by the printer is too long and exceeds the actual needs, and the paper needs to be retracted, the drive source drives the first gear to rotate in the first direction. At this time, the swing arm switches from the first state to the second state, and the paper roller shaft rotates in the opposite direction to retract the paper. At this time, the third gear is separated from the second gear, and with the anti-stopping effect of the swing arm, the ribbon roller shaft is stably kept in the current stationary state. This design ensures that used ribbons do not re-pass through the printhead as the paper retracts. Ribbons that do not retract with the paper remain in the position after their first print, and the distribution of remaining toner is relatively fixed. This avoids the uneven and loosely adhered toner that cannot be transferred to the paper as evenly and completely as a brand new ribbon when it passes through the printhead a second time. This effectively prevents the printing quality from deteriorating, ensuring that the printed text is clear, the image colors are uniform, and there are no spots or streaks or other quality issues, thus guaranteeing the printing effect. Attached Figure Description

[0008] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0009] Figure 1 This is one of the schematic diagrams of the printer mechanism in an embodiment of this application; Figure 2 This is one of the exploded schematic diagrams of the printer mechanism according to an embodiment of this application; Figure 3 This is a second schematic diagram of the printer mechanism according to an embodiment of this application; Figure 4 This is a cross-sectional schematic diagram of the printer mechanism according to an embodiment of this application; Figure 5 This is a schematic diagram of the connection between the adapter and the damping bushing according to an embodiment of this application; Figure 6 This is the second exploded view of the printer mechanism in an embodiment of this application.

[0010] In the picture: 100, Frame; 200, Swing arm; 210, Mounting slot; 220, Pawl portion; 300, First gear; 400, Second gear; 410, First ratchet portion; 500, Third gear; 510, Second ratchet portion; 520, Positioning protrusion; 600, First elastic element; 700, Second elastic element; 800, Paper roller shaft; 900, Carbon ribbon roller shaft; 910, Disc portion; 911, Insertion recess; 1000, Damping bushing; 1010, Inner ring portion; 1020, Outer ring portion; 1021, Positioning recess; 1030, Accommodation gap; 1100, Adapter; 1110, Insertion portion; 1200, Fourth gear; 1300, Drive source; a, First direction; b, Second direction. Detailed Implementation

[0011] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be described in detail below. Obviously, the described embodiments are merely some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other implementation methods obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0012] This application provides a printer mechanism and a printer, which are described below in conjunction with the accompanying drawings. Figures 1-6 The printer mechanism and printing provided in this application will be described in detail through specific embodiments and application scenarios.

[0013] like Figure 1 , Figure 2 and Figure 3 As shown in the figure, this application discloses a printer mechanism. The disclosed printer mechanism is applied to a printer, especially to the linkage between the paper roller and the ribbon roller in the printer. Specifically, the disclosed printer mechanism includes a frame 100, a swing arm 200, a first gear 300, a second gear 400, and a third gear 500. The frame 100 is the basic component of the printer mechanism and can provide an installation base for the swing arm 200, the first gear 300, the second gear 400, and the third gear 500. The swing arm 200, the first gear 300, the second gear 400, and the third gear 500 are all rotatably arranged relative to the frame 100.

[0014] Specifically, the swing arm 200 has a mounting groove 210, and the first gear 300 is assembled in the mounting groove 210. The first gear 300 and the swing arm 200 are closely engaged. It should be noted that, in the embodiments of this application, the close engagement between the first gear 300 and the swing arm 200 means that there is a certain frictional force between the first gear 300 and the swing arm 200. When the first gear 300 is driven to rotate, the frictional force between it and the swing arm 200 can prevent relative sliding between the first gear 300 and the swing arm 200, and the two maintain synchronous rotation (the swing arm 200 swings relative to the frame 100) until the swing arm 200 is subjected to external resistance (for example, the swing arm 200 abuts against the frame 100) and the external resistance is greater than the maximum static friction force between the swing arm 200 and the first gear 300.

[0015] For example, the swing arm 200 can be a plastic component. The two sides of the first gear 300 are tightly attached to the corresponding two side walls of the mounting groove 210. That is, the two side walls of the mounting groove 210 have a clamping effect on the first gear 300. When the first gear 300 is driven to rotate, it can drive the swing arm 200 to rotate synchronously until the swing of the swing arm 200 is limited. The rotation of the swing arm 200 can switch between the first state and the second state. The first state and the second state of the swing arm 200 will be described in detail later.

[0016] In this embodiment, the second gear 400 meshes with the first gear 300, and the rotation of the first gear 300 directly drives the second gear 400 to rotate, and the two rotate in opposite directions. Figure 2 As shown, a one-way clutch structure is provided between the second gear 400 and the third gear 500. When the second gear 400 rotates along the first direction a, the second gear 400 can drive the third gear 500 to rotate synchronously along the first direction a through the one-way clutch structure. When the second gear 400 rotates along the second direction b, the one-way clutch structure disengages the transmission relationship between the second gear 400 and the third gear 500. At this time, the second gear 400 cannot transmit torque to the third gear 500, that is, the third gear 500 cannot rotate along the second direction b. The first direction a and the second direction b are opposite to each other. For example, the first direction a can be... Figure 2 In the counterclockwise direction, the second direction b can be Figure 2 The clockwise direction in the middle.

[0017] It is understood that the rotation direction of the first gear 300 determines the current state of the swing arm 200 and the rotation direction of the second gear 400. In this embodiment, when the first gear 300 rotates along the first direction a, the swing arm 200 can switch from the second state to the first state. At this time, the swing arm 200 swings clockwise and separates from the third gear 500. When the first gear 300 rotates along the second direction b, the swing arm 200 can switch from the first state to the second state. At this time, the swing arm 200 swings counterclockwise and lifts up to abut against the third gear 500 to restrict the rotation of the third gear 500.

[0018] When the drive source 1300 drives the first gear 300 to rotate clockwise, the swing arm 200 can swing clockwise until it abuts against the frame 100. At this time, the swing arm 200 is in the first state. The second gear 400, which meshes with the first gear 300, rotates counterclockwise and drives the third gear 500 to rotate counterclockwise through the one-way clutch structure. When the drive source 1300 drives the first gear 300 to rotate counterclockwise, the swing arm 200 swings counterclockwise and lifts up until it abuts against the third gear 500. The second gear 400, which meshes with the first gear 300, rotates clockwise. The third gear 500 separates from the second gear 400 and remains in the current non-rotating state. Based on the abutment of the swing arm 200, the stability of the third gear 500 in the current state can be ensured.

[0019] When the printer mechanism of this embodiment is applied to a printer, the first gear 300 can be connected to the paper roller shaft 800 for transmission, and the third gear 500 can be coaxially connected to the ribbon roller shaft 900. As mentioned above, the rotation direction of the first gear 300 is opposite to the rotation direction of the second gear 400 and the third gear 500. To ensure the same direction of rotation of the paper roller shaft 800 and the ribbon roller shaft 900 during synchronous rotation, as follows... Figure 3 As shown, the first gear 300 is also meshed with a fourth gear 1200, and the paper roller shaft 800 is coaxially connected with the fourth gear 1200.

[0020] With this setup, during paper feeding, the drive source 1300 drives the first gear 300 to rotate clockwise, and simultaneously drives the third gear 500 and the fourth gear 1200 to rotate counterclockwise. That is, the paper roller shaft 800 and the ribbon roller shaft 900 rotate synchronously, and the ribbon is wound up simultaneously for inking during paper feeding. When the paper output by the printer is too long and the paper needs to be retracted, the drive source 1300 drives the first gear 300 to rotate counterclockwise, and the fourth gear 1200 drives the paper roller shaft 800 to rotate clockwise to retract the paper. At this time, the third gear 500 is separated from the second gear 400, and with the stop action of the swing arm 200, the ribbon roller shaft 900 is kept stably in its current stationary state.

[0021] This design ensures that used ribbons do not re-pass through the printhead as the paper retracts. Ribbons that do not retract with the paper remain in the position after their first print, and the distribution of their remaining toner is relatively fixed. This avoids the uneven and loosely adhered toner that cannot be transferred to the paper as evenly and completely as a brand new ribbon when it passes through the printhead a second time. This effectively prevents the printing effect from deteriorating, ensuring that the printed text is clear, the image color is uniform, and there are no quality problems such as spots or streaks.

[0022] As mentioned above, the first gear 300 and the swing arm 200 are closely matched. The rotation of the first gear 300 can drive the swing arm 200 to swing synchronously until the swing of the swing arm 200 is limited. However, after the printer has been used for a long time, the swing arm 200 may loosen its grip on the first gear 300.

[0023] Given this situation, such as Figure 1 and Figure 2 As shown, in some embodiments of this application, the printer mechanism may further include a first elastic element 600, which is connected to at least one of the swing arm 200 and the first gear 300. The first elastic element 600 is configured to apply an elastic force to at least one of the swing arm 200 and the first gear 300, so that the swing arm 200 and the first gear 300 are kept in a tightly engaged state.

[0024] For example, such as Figure 1 As shown, the first elastic element 600 can be an elastic clip, which can clamp the outer sides of the two side walls of the mounting groove 210, thereby pressing the two side walls of the mounting groove 210 inward, so that the two side walls of the mounting groove 210 abut against the two sides of the first gear 300 to maintain a tight fit; or, the first elastic element 600 can be a helical spring provided in the mounting groove 210, one end of which abuts against one side of the first gear 300, and the other end of which abuts against one side wall of the mounting groove 210, which can also make the other side of the first gear 300 abut against the other side wall of the mounting groove 210 to maintain a tight fit; or, the first elastic element 600 can be an elastic clip, one side of which is fixed, for example, it can be fixed to the frame 100, and the other side of which abuts against the first gear 300, so that the first gear 300 abuts against the side wall of the mounting groove 210 to maintain a tight fit. In other words, the first elastic element 600 can be arranged in various ways, as long as the rocker arm 200 and the first gear 300 can maintain a tight fit. This application does not impose any specific restrictions on this.

[0025] When the clamping action of the rocker arm 200 on the first gear 300 tends to loosen, the elastic force of the first elastic element 600 will promptly come into play to compensate for this loosening tendency, continuing to apply force to the rocker arm 200 and / or the first gear 300, so that they regain a tight fit. This ensures that the first gear 300 can stably drive the rocker arm 200 to swing until the swing of the rocker arm 200 is restricted to a first or second state. It is understandable that when the rocker arm 200 is in the first or second state, because the swing of the rocker arm 200 is restricted, the first gear 300 can rotate relative to the rocker arm 200 to ensure normal torque transmission.

[0026] In the embodiments of this application, such as Figure 2 , Figure 3 and Figure 4 As shown, the one-way clutch structure includes a first ratchet portion 410 and a second ratchet portion 510, wherein the first ratchet portion 410 is disposed on the second gear 400, and the second ratchet portion 510 is disposed on the third gear 500, and the first ratchet portion 410 and the second ratchet portion 510 are opposite to each other and in a meshing engagement state. Figure 2 and Figure 4 As shown, when the second gear 400 rotates along the first direction a, the first ratchet part 410 and the second ratchet part 510 can transmit torque to drive the third gear 500 to rotate. When the second gear 400 rotates along the second direction b, the first ratchet part 410 slides relative to the second ratchet part 510. At this time, the swing arm 200 switches from the first state to the second state and abuts against the third gear 500 to keep the third gear 500 stable.

[0027] In the embodiments of this application, such as Figure 2 and Figure 4As shown, the printer mechanism may further include a second elastic element 700, which is connected to the third gear 500. The second elastic element 700 is configured to apply an elastic force to the third gear 500, causing the first ratchet portion 410 and the second ratchet portion 510 to axially abut against each other. For example, the second elastic element 700 may be a coil spring, with one end abutting against the frame 100 and the other end against the side of the third gear 500 opposite to the second gear 400. That is, after installation, the coil spring is in a compressed state, thereby applying an axial elastic force to the third gear 500, causing the second ratchet portion 510 and the first ratchet portion 410 to axially abut against each other. When the second gear 400 rotates along the first direction a, the first ratchet portion 410 and the second ratchet portion 510 mesh tightly to transmit torque. The introduction of the second elastic member 700 can reduce or even eliminate the gap between the first ratchet portion 410 and the second ratchet portion 510, thus avoiding torque loss or unstable transmission. When the second gear 400 rotates along the second direction b, the helical spring can undergo a certain axial deformation to adapt to the floating of the third gear 500 in the axial direction.

[0028] In this embodiment, the third gear 500 can be a spur gear or a helical gear, and is preferably a helical gear, such as... Figure 2 and Figure 3 As shown, the teeth of the third gear 500 face the second direction b. The rocker arm 200 has a pawl portion 220. When the rocker arm 200 switches from the first state to the second state, the pawl portion 220 of the rocker arm 200 can swing and probe into the tooth gap of the third gear 500 to restrict the rotation of the third gear 500. Since the teeth of the helical gear are inclined, the contact surface between the pawl portion 220 and the teeth is larger, which can generate greater friction and resistance, thereby more effectively restricting the rotation of the third gear 500.

[0029] like Figures 2-6 As shown, the disclosed printer mechanism also includes a paper roller shaft 800, a ribbon roller shaft 900, and the aforementioned printer mechanism. The paper roller shaft 800 is connected to the first gear 300, and the ribbon roller shaft 900 is connected to the third gear 500. To ensure the consistency of the rotation direction of the paper roller shaft 800 and the ribbon roller shaft 900, the printer mechanism also includes a fourth gear 1200 rotatably disposed relative to the frame 100. The fourth gear 1200 meshes with the first gear 300. The paper roller shaft 800 is coaxially connected to the fourth gear 1200, and the ribbon roller shaft 900 is coaxially connected to the third gear 500.

[0030] In the embodiments of this application, such as Figure 2 , Figure 4 and Figure 6As shown, the printer mechanism also includes a damping bushing 1000 and an adapter 1100. The damping bushing 1000 is fitted onto the ribbon roller shaft 900 and is located inside the third gear 500. A concave-convex fitting structure is provided between the third gear 500 and the damping bushing 1000. The concave-convex fitting structure is configured to allow the damping bushing 1000 to rotate with the rotation of the third gear 500. In other words, the concave-convex fitting structure can transmit the torque of the third gear 500 to the damping bushing 1000.

[0031] In this embodiment, the adapter 1100 connects the damping sleeve 1000 and the carbon ribbon roller shaft 900. The adapter 1100 is configured to transmit torque between the damping sleeve 1000 and the carbon ribbon roller shaft 900, so that the carbon ribbon roller shaft 900 rotates with the damping sleeve 1000. When the rotational damping of the carbon ribbon roller shaft 900 exceeds a preset threshold, the damping sleeve 1000 and the adapter 1100 slide relative to each other, that is, slippage occurs between the damping sleeve 1000 and the adapter 1100. For example, the adapter 1100 can be a helical spring or a ring-shaped component. The adapter 1100 can be connected to the damping sleeve 1000 in a tight fit manner, so that the torque of the damping sleeve 1000 can be transmitted to the carbon ribbon roller shaft 900, and slippage can occur when the rotational damping of the carbon ribbon roller shaft 900 is large.

[0032] Based on the above technical solution, on the one hand, the damping sleeve 1000 itself has certain damping characteristics, which can play a buffering and stabilizing role in the torque transmission process. For example, when the rotation speed of the third gear 500 changes instantaneously, the damping sleeve 1000 can absorb some of the impact energy, making the torque transmitted to the ribbon roller shaft 900 more stable, reducing fluctuations in the ribbon conveying process, and improving printing quality. On the other hand, when the speed of the ribbon roller shaft 900 is faster than that of the paper roller shaft 800 due to the difference in the transmission path, the rotational damping of the ribbon roller shaft 900 will gradually increase until it exceeds the preset threshold. At this time, the damping sleeve 1000 and the adapter 1100 slide relative to each other (slippage) and cut off the torque transmission. The speed of the ribbon roller shaft 900 naturally decreases until it is rematched with the speed of the paper roller shaft 800. Compared with the traditional rigid key connection, this method can avoid the ribbon being overstretched, which could cause the ribbon to break or the transmission system to jam.

[0033] In the embodiments of this application, such as Figure 2As shown, the concave-convex adapter structure includes a matching positioning protrusion 520 and a positioning recess 1021. One of the positioning protrusion 520 and the positioning recess 1021 is located on the third gear 500, and the other is located on the damping bushing 1000. For example, the inner side of the third gear 500 is provided with a plurality of positioning protrusions 520 distributed circumferentially thereon, and the outer side of the damping bushing 1000 is provided with a plurality of positioning recesses 1021 distributed circumferentially thereon. The positioning protrusions 520 and the positioning recesses 1021 are positioned and matched. The plurality of positioning protrusions 520 and the positioning recesses 1021 are distributed circumferentially. This distribution method can ensure that the torque can be transmitted evenly during rotation, and avoid structural damage or transmission instability caused by uneven local force. At the same time, the cooperation of multiple positioning protrusions 520 and positioning recesses 1021 also increases the reliability and stability of torque transmission. Even if some of the positioning protrusions 520 and positioning recesses 1021 have a problem with cooperation, the other positioning protrusions 520 and positioning recesses 1021 can still continue to transmit torque.

[0034] In the embodiments of this application, such as Figure 5 As shown, the damping bushing 1000 includes an inner ring portion 1010 and an outer ring portion 1020. The inner ring portion 1010 is connected to the outer ring portion 1020 to form a receiving gap 1030 between them. The inner ring portion 1010 is sleeved on the carbon ribbon roller shaft 900. The receiving gap 1030 is used to receive the adapter 1100. The outer side of the adapter 1100 is tightly fitted with the inner side of the outer ring portion 1020. When the damping bushing 1000 rotates, the static friction between the outer ring portion 1020 and the adapter 1100 can drive the carbon ribbon roller shaft 900 to rotate. When the resistance experienced by the carbon ribbon roller shaft 900 causes the torque transmission capacity of the adapter 1100 to reach its limit, the friction between the adapter 1100 and the outer ring portion 1020 is insufficient to maintain the synchronous rotation of the carbon ribbon roller shaft 900 and the paper roller shaft 800, resulting in slippage until the speeds of the two are rematched.

[0035] In the embodiments of this application, such as Figure 2 and Figure 6 As shown, the carbon belt roller shaft 900 is provided with a radially protruding disc portion 910, and the disc portion 910 is provided with an insertion recess 911. The adapter 1100 has an insertion portion 1110, which is engaged with the insertion recess 911 to achieve torque transmission.

[0036] This application also discloses a printer, which includes the aforementioned printer mechanism.

[0037] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0038] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A printer mechanism, characterized in that, It includes a frame (100) and a swing arm (200) rotatably mounted on the frame (100), a first gear (300), a second gear (400), and a third gear (500); wherein: The swing arm (200) has a mounting groove (210), the first gear (300) is fitted into the mounting groove (210), and the first gear (300) is in close contact with the swing arm (200), so that the swing arm (200) can rotate with the rotation of the first gear (300) to switch between a first state and a second state. The second gear (400) meshes with the first gear (300), and a one-way clutch structure is provided between the second gear (400) and the third gear (500). When the second gear (400) rotates in the first direction, the one-way clutch structure is configured to drive the third gear (500) to rotate synchronously. In the first state, the swing arm (200) is separated from the third gear (500), so that the third gear (500) can rotate with the rotation of the second gear (400); in the second state, the swing arm (200) abuts against the third gear (500) to restrict the rotation of the third gear (500).

2. The printer mechanism according to claim 1, characterized in that, It also includes a first elastic element (600) connected to at least one of the swing arm (200) and the first gear (300), the first elastic element (600) being configured to apply an elastic force to at least one of the swing arm (200) and the first gear (300) so that the swing arm (200) and the first gear (300) are in close engagement.

3. The printer mechanism according to claim 1, characterized in that, The one-way clutch structure includes a first ratchet part (410) and a second ratchet part (510), wherein the first ratchet part (410) is disposed on the second gear (400), the second ratchet part (510) is disposed on the third gear (500), and the first ratchet part (410) and the second ratchet part (510) cooperate with each other.

4. The printer mechanism according to claim 3, characterized in that, It also includes a second elastic element (700) connected to the third gear (500), the second elastic element (700) being configured to apply an elastic force to the third gear (500) so that the first ratchet portion (410) and the second ratchet portion (510) abut against each other axially.

5. The printer mechanism according to claim 1, characterized in that, The teeth of the third gear (500) are unidirectionally inclined, and the teeth of the third gear (500) are inclined in the second direction. The swing arm (200) has a pawl (220). In the second state, the pawl (220) probes into the tooth gap of the third gear (500) to restrict the rotation of the third gear (500).

6. The printer mechanism according to any one of claims 1 to 5, characterized in that, It also includes a paper roller shaft (800) and a carbon ribbon roller shaft (900). The paper roller shaft (800) is connected to the first gear (300) for transmission. The paper roller shaft (800) can rotate with the rotation of the first gear (300). The carbon ribbon roller shaft (900) is connected to the third gear (500).

7. The printer mechanism according to claim 6, characterized in that, It also includes a damping bushing (1000) and an adapter (1100); wherein: The damping bushing (1000) is located between the third gear (500) and the carbon belt roller shaft (900). A concave-convex fitting structure is provided between the third gear (500) and the damping bushing (1000). The concave-convex fitting structure is configured to allow the damping bushing (1000) to rotate with the rotation of the third gear (500). The adapter (1100) connects the damping bushing (1000) and the carbon belt roller shaft (900). The adapter (1100) is configured to transmit torque between the damping bushing (1000) and the carbon belt roller shaft (900), and when the rotational damping of the carbon belt roller shaft (900) exceeds a preset threshold, the damping bushing (1000) and the adapter (1100) slide relative to each other.

8. The printer mechanism according to claim 7, characterized in that, The concave-convex adapter structure includes a matching positioning protrusion (520) and a positioning recess (1021). One of the positioning protrusion (520) and the positioning recess (1021) is located on the third gear (500), and the other is located on the damping bushing (1000). The positioning protrusion (520) and the positioning recess (1021) extend in the axial direction of the carbon belt roller shaft (900).

9. The printer mechanism according to claim 7, characterized in that, The damping bushing (1000) includes an inner ring portion (1010) and an outer ring portion (1020). One end of the inner ring portion (1010) is integrally connected to one end of the outer ring portion (1020) to form a receiving gap (1030) between them. The receiving gap (1030) is used to receive the adapter (1100), and the adapter (1100) is tightly fitted with the inner side of the outer ring portion (1020). And / or, the carbon belt roller shaft (900) is provided with a radially protruding disc portion (910), the disc portion (910) is provided with a plug-in recess (911), the adapter (1100) has a plug-in portion (1110), the plug-in portion (1110) is plugged into the plug-in recess (911).

10. A printer, characterized in that, Includes the printer mechanism as described in any one of claims 1 to 9.

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