Thermal transfer printer ribbon tension stability control system and method

Abstract

The application discloses a thermal transfer printer ribbon tension stable control system and method. The system comprises a first driving assembly, a second driving assembly and a control module; the first driving assembly is connected with the second driving assembly through a ribbon; the control module is electrically connected with the first and second driving assemblies; in an initialization stage, the control module controls the first driving assembly to be in a motor mode and the second driving assembly to be in a power generation braking mode to make the ribbon forwardly travel a preset distance, and controls the first driving assembly to be switched to the power generation braking mode and the second driving assembly to be switched to a motor module to make the ribbon reversely travel a preset distance; in a thermal printing stage, the control module controls the first driving assembly to be switched to the motor mode again and the second driving assembly to be switched to the power generation braking module again to make the ribbon forwardly travel a thermal printing distance, and controls the first driving assembly to be switched to the power generation braking mode again and the second driving assembly to be switched to the motor module again to make the ribbon reversely travel a thermal printing distance. The application realizes stable control of the ribbon tension.

Description

Technical Field

[0001] This invention relates to the field of thermal transfer printing technology, and more particularly to a thermal transfer printer ribbon tension stabilization control system and method. Background Technology

[0002] In thermal transfer printers, to transfer the thermal transfer material from the ribbon to the packaging film, the ribbon tension needs to be maintained within a certain range. After one pattern is transferred, the ribbon needs to be fed to repeat the next transfer operation. For continuous thermal transfer, not only does the ribbon need to travel forward, but also needs to be stretched backward to a certain position to save ribbon and ensure continuous transfer. This process requires the ribbon to maintain a certain tension.

[0003] For conventional thermal transfer printers, including take-up and unwind stepper motors, the take-up and unwind motors move synchronously as the ribbon travels. Tension is controlled mechanically and by pressure during this movement to ensure stability. However, these methods have relatively complex mechanical structures and controls, and tension detection is often delayed, leading to tension instability. This results in unclear prints, inconsistent quality, a tendency for ribbon breakage, or slowed printing speeds, and is also relatively expensive. Summary of the Invention

[0004] This invention provides a control system and method for stabilizing the ribbon tension in a thermal transfer printer, achieving stable control of the ribbon tension during the thermal printing process.

[0005] To achieve the above objectives, in a first aspect, embodiments of the present invention provide a thermal printer ribbon tension stabilization control system, the system comprising: a first driving component, a second driving component, and a control module; the first driving component is connected to the second driving component via a ribbon;

[0006] The control module is electrically connected to the first drive component and the second drive component; the control module is used to control the first drive component to be in motor mode and the second drive component to be in generator braking mode during the initialization phase so that the ribbon travels forward a preset distance, and to control the first drive component to switch to generator braking mode and the second drive component to switch to motor mode so that the ribbon travels backward a preset distance.

[0007] It is also used to control the first drive component to switch back to the motor mode and the second drive component to switch back to the power generation braking mode during the thermal printing stage so that the ribbon travels the thermal printing distance in the forward direction, and to control the first drive component to switch back to the power generation braking mode and the second drive component to switch back to the motor mode so that the ribbon travels the thermal printing distance in the reverse direction.

[0008] Optionally, the first drive assembly includes at least two phases of first stator coils, a first rotor, at least one first damping resistor, and at least one first control switch; the maximum number of the first damping resistors is the same as the number of the first stator coils; the first damping resistors and the first control switch are connected in series; the first stator coils are connected in parallel with the first damping resistors and the first control switch.

[0009] Controlling the first drive component to be in motor mode includes:

[0010] The control module outputs pulse current to each of the first stator coils in the first drive assembly according to the first rotation command, and controls each of the first control switches to disconnect so that the first drive assembly is in the motor mode;

[0011] Controlling the first drive component to be in generator braking mode includes:

[0012] The control module controls the non-output of pulse current to each of the first stator coils in the first drive assembly according to the first braking command, and controls at least one of the first control switches to open at a first variable switching frequency so that the first drive assembly is in the power generation braking mode.

[0013] Optionally, the second drive assembly includes at least two phases of second stator coils, a second rotor, at least one second damping resistor, and at least one second control switch; the maximum number of the second damping resistors is the same as the number of the second stator coils.

[0014] The second damping resistor and the second control switch are connected in series; the second stator coil is connected in parallel with the second damping resistor and the second control switch.

[0015] Controlling the second drive component to be in motor mode includes:

[0016] The control module outputs pulse current to each of the second stator coils in the second drive assembly according to the second rotation command, and controls the second control switch to open so that the second drive assembly is in the motor mode;

[0017] Controlling the second drive component to be in generator braking mode includes:

[0018] The control module controls the output of pulse current to each of the second stator coils in the second drive assembly according to the second braking command, and controls at least one of the second control switches to open at a second variable switching frequency so that the second drive assembly is in the power generation braking mode.

[0019] Optionally, the control module includes a first controller and a second controller;

[0020] The first controller is used to control the first drive component or the second drive component to be in the motor mode;

[0021] The second controller is used to control the first drive component or the second drive component to be in the power generation and braking mode.

[0022] Optionally, the control module further includes a tension determination unit;

[0023] The tension determining unit is used to detect the tension of the ribbon on the ribbon based on the current in the first damping resistor or the second damping resistor.

[0024] Secondly, embodiments of the present invention also provide a method for stabilizing the tension of a thermal printing ribbon, which is applied to the thermal printing ribbon tension stabilization control system described in the first aspect above. The thermal printing ribbon tension stabilization control method includes:

[0025] During the initialization phase, the first drive component is controlled to be in motor mode and the second drive component is controlled to be in generator braking mode so that the ribbon travels forward a preset distance, and the first drive component is controlled to switch to generator braking mode and the second drive component is controlled to switch to motor mode so that the ribbon travels backward a preset distance;

[0026] Determine whether the preset distance is greater than the initial distance;

[0027] If so, the process enters the thermal printing stage, controlling the first drive component to switch to the motor mode and the second drive component to switch to the power generation braking mode to make the ribbon travel the thermal printing distance in the forward direction, and controlling the first drive component to switch to the power generation braking mode and the second drive component to switch to the motor mode to make the ribbon travel the thermal printing distance in the reverse direction.

[0028] Optionally, the first drive component is controlled to be in motor mode, specifically:

[0029] According to the first rotation command, a pulse current is output to each of the first stator coils in the first drive assembly, and each of the first control switches is controlled to be turned off so that the first drive assembly is in motor mode.

[0030] Specifically, controlling the first drive component to be in generator braking mode involves:

[0031] According to the first braking command, the pulse current is not output to each of the first stator coils in the first drive assembly, and at least one of the first control switches is controlled to open at a first variable switching frequency so that the first drive assembly is in the generator braking mode.

[0032] Optionally, the second drive component is controlled to be in motor mode, specifically:

[0033] According to the second rotation command, a pulse current is output to each of the second stator coils in the second drive assembly, and the second control switch is controlled to open so that the second drive assembly is in motor mode;

[0034] Specifically, the second drive component is controlled to be in the power generation and braking mode, as follows:

[0035] According to the second braking command, the pulse current is not output to each of the second stator coils in the second drive assembly, and at least one of the second control switches is controlled to open at a second variable switching frequency so that the second drive assembly is in the generator braking mode.

[0036] Optional, also includes:

[0037] Receive current from the first damping resistor or the second damping resistor;

[0038] The tension of the ribbon is detected based on the current in the first damping resistor or the second damping resistor.

[0039] In this embodiment of the invention, the first driving component is connected to the second driving component via a ribbon; the control module is electrically connected to both the first and second driving components. During the initialization phase, the control module controls the first driving component to be in motor mode and the second driving component to be in generator braking mode to allow the ribbon to travel a preset distance in the forward direction. It then controls the first driving component to switch to generator braking mode and the second driving component to switch to motor mode to allow the ribbon to travel the preset distance in the reverse direction. This ensures stable control of the ribbon tension during the thermal printing initialization phase, avoiding instability caused by synchronous movement of the driving components. Simultaneously, during the thermal printing phase, the control module controls the first driving component to switch back to motor mode and the second driving component to switch back to generator braking mode to allow the ribbon to travel the thermal printing distance in the forward direction. It then controls the first driving component to switch back to generator braking mode and the second driving component to switch back to motor mode to allow the ribbon to travel the thermal printing distance in the reverse direction, thus achieving stable control of the ribbon tension during the thermal printing process. Attached Figure Description

[0040] Figure 1 This is a schematic diagram of the structure of a ribbon tension stabilization control system for a thermal transfer printer provided in an embodiment of the present invention;

[0041] Figure 2 This is a schematic diagram of the specific structure of a thermal transfer printer ribbon tension stabilization control system provided in an embodiment of the present invention;

[0042] Figure 3 This is a flowchart of a method for stabilizing the tension of a thermal transfer printer ribbon, provided in an embodiment of the present invention.

[0043] Figure 4 This is a flowchart of another method for stabilizing the tension of a thermal transfer printer ribbon, provided in an embodiment of the present invention. Detailed Implementation

[0044] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0045] Figure 1 This is a schematic diagram of the structure of a ribbon tension stabilization control system for a thermal transfer printer provided in an embodiment of the present invention, as shown below. Figure 1 As shown, the system includes a first drive component 10, a second drive component 20, and a control module 30. The first drive component 10 is connected to the second drive component 20 via a ribbon 40. The control module 30 is connected to the first drive component 10 and the second drive component 20 via electrical signals. During the initialization phase, the control module 30 controls the first drive component 10 to be in motor mode and the second drive component 20 to be in generator braking mode so that the ribbon 40 travels a preset distance in the forward direction. It also controls the first drive component 10 to switch to generator braking mode and the second drive component 20 to switch to motor mode so that the ribbon 40 travels a preset distance in the reverse direction.

[0046] It is also used to control the first drive component 10 to switch to motor mode and the second drive component 20 to switch to generator braking mode during the thermal printing stage so that the ribbon travels forward for the thermal printing distance, and to control the first drive component 10 to switch to generator braking mode and the second drive component 20 to switch to motor module so that the ribbon travels backward for the thermal printing distance.

[0047] The first drive assembly 10 and the second drive assembly 20 each include two working modes: a motor mode and a generator braking mode. In the motor mode, each drive assembly generates traction force to drive the drive assembly forward. In the generator braking mode, each drive assembly generates braking force to prevent the drive assembly from moving forward and instead moves backward.

[0048] The actual thermal printing process is divided into an initialization phase and a thermal printing phase. During the initialization phase, the control module 30 controls the first drive component 10 to be in motor mode and the second drive component 20 to be in generator braking mode. If the traction force generated by the first drive component 10 in motor mode is greater than the braking force generated by the second drive component 20 in generator braking mode, the ribbon 40 travels forward. When the ribbon 40 has traveled a preset distance in the forward direction, the control module 30 switches the first drive component 10 to generator braking mode and the second drive component 20 to motor mode.

[0049] If the braking force of the first drive component 10 in generator braking mode is less than the traction force generated by the second drive component 20 switching to motor mode, the ribbon 40 travels in the opposite direction a preset distance; thus, during the initialization phase, because...

[0050] The two drive components move in opposite directions and not in a synchronous direction, which keeps the ribbon constantly stable.

[0051] Simultaneously, during the thermal printing stage, the first drive component 10 is switched to motor mode and the second drive component 20 is switched to generator braking mode. If the traction force generated by the first drive component 10 in motor mode is greater than the braking force generated by the second drive component 20 in generator braking mode, the ribbon travels in the forward direction. To save ribbon and ensure continuous transfer, when the ribbon has traveled the thermal printing distance in the forward direction, the first drive component 10 is switched back to generator braking mode and the second drive component 20 is switched back to motor mode. If the braking force generated by the first drive component 10 in generator braking mode is less than the traction force generated by the second drive component 20 in motor mode, the ribbon travels the thermal printing distance in the reverse direction. Thus, during the thermal printing stage, because the two drive components move in opposite directions and not in a synchronous direction, the ribbon remains stable.

[0052] Optionally, the above embodiments can be further refined. Figure 2 This is a schematic diagram of the specific structure of a thermal transfer printer ribbon tension stabilization control system provided in an embodiment of the present invention, as shown below. Figure 2 As shown, the first drive assembly 10 includes at least two phases of first stator coils 11 ( Figure 2 The diagram shows a three-phase first stator coil, a first rotor 12, at least one first damping resistor 13, and at least one first control switch 14; the maximum number of first damping resistors is the same as the number of first stator coils; the first damping resistor 13 and the first control switch 14 are connected in series; the first stator coil 11 is connected in parallel with the first damping resistor 13 and the first control switch 14.

[0053] The second drive assembly 20 includes at least two-phase second stator coils 21, a second rotor 22, at least one second damping resistor 23, and at least one second control switch 24; the maximum number of second damping resistors is the same as the number of second stator coils 21; the second damping resistors 23 and the second control switch 24 are connected in series; the second stator coils 21 are connected in parallel with the second damping resistors 23 and the second control switch 24.

[0054] In motor mode, the first drive component 10 and the second drive component 20 work on the same principle as a two-phase motor or a three-phase motor. That is, the control module 30 outputs pulse current to each phase stator coil, and each phase stator coil generates a magnetic field, which interacts with the magnetic field generated by the rotor, thereby driving the rotor to rotate, thus making the two-phase motor or the three-phase motor rotate.

[0055] The working principle of either the first drive assembly 10 or the second drive assembly 20 in the generator braking mode is as follows: Utilizing the principle of electromagnetic induction, the control module 30 does not output pulse current to each phase stator coil. At this time, since the other drive assembly is in motor mode, it will drive the rotor within that drive assembly to rotate, thereby generating a changing magnetic field. This changing magnetic field induces an electromotive force in each phase stator coil. Thus, each phase stator coil, damping resistor, and control switch form a closed loop that generates a damping current. This damping current generates a braking force that prevents the rotor from moving. The magnitude of the damping current is proportional to the braking force and also proportional to the ribbon tension. In this embodiment, the magnitude of the damping current can be adjusted by adjusting the frequency of the control switch, thereby adjusting the magnitude of the braking force and thus the magnitude of the ribbon tension; or the magnitude of the damping current can be adjusted by adjusting the magnitude of the damping resistor.

[0056] Specifically, the first drive assembly 10 is controlled to be in motor mode, that is, the control module 30 outputs pulse current to each of the first stator coils 11 in the first drive assembly 10 according to the first rotation command, and controls each of the first control switches 14 to be open so that the first drive assembly 10 is in motor mode; the first drive assembly 10 is controlled to be in generator braking mode, that is, the control module 30 controls not to output pulse current to each of the first stator coils 11 in the first drive assembly according to the first braking command, and controls at least one of the first control switches 14 to be opened at a preset first variable switching frequency so that the first drive assembly 10 is in generator braking mode. Similarly, the second drive assembly 20 is controlled to be in motor mode, that is, the control module 30 outputs pulse current to each of the second stator coils 21 in the second drive assembly 20 according to the second rotation command, and controls the second control switch 24 to be open so that the second drive assembly 20 is in motor mode; the second drive assembly 20 is controlled to be in generator braking mode, that is, the control module 30 controls not to output pulse current to each of the second stator coils 21 in the second drive assembly according to the second braking command, and controls at least one of the second control switches 24 to be opened at a second variable switching frequency so that the second drive assembly 20 is in generator braking mode.

[0057] It is understood that in this embodiment, the number of stator coils in each drive component can be two-phase or three-phase; there is no specific limitation on the number of stator coils in the drive component. In addition, the number of damping resistors and control switches in each drive component can be determined according to the actual required braking force generated by the drive component in the generator braking mode. If the required braking force is large, the number of damping resistors and control switches can be the same as the number of stator coils; if the required braking force is small, the number of damping resistors and control switches can be less than the number of stator coils. For example, if the first stator coil of the first drive component is two-phase, the number of the first damping resistor and the first control switch can both be set to 1 or 2; if the first stator coil of the first drive component is three-phase, the number of the first damping resistor and the first control switch can both be set to one, two, or three. There is no specific limitation on the number of damping resistors and control switches in the drive component.

[0058] Optional, continue to refer to Figure 2 The control module 30 includes a first controller 31 and a second controller 32. The first controller 31 is used to control the first drive component 10 or the second drive component 20 to be in motor mode. The second controller 32 is used to control the first drive component 10 or the second drive component 20 to be in generator braking mode. The first controller 31 and the second controller 32 are set separately for motor mode and generator braking mode control, respectively, to achieve redundant control.

[0059] Optional, continue to refer to Figure 2The control module 30 also includes a tension determination unit 33; the tension determination unit 33 is used to detect the tension of the ribbon on the ribbon based on the current in the first damping resistor or the second damping resistor. The magnitude of the damping current is proportional to the braking force and also proportional to the ribbon tension. In this embodiment, the tension determination unit 33 can detect the ribbon tension on the ribbon in real time based on the current in the first damping resistor or the second damping resistor, resulting in higher detection accuracy and avoiding the problems of complex overall system structure and low accuracy caused by detection using pressure sensors in the prior art.

[0060] Based on the same inventive concept, this invention also provides a method for stabilizing the tension of a thermal transfer printer ribbon, which is applied to the thermal transfer printer ribbon tension stabilization control system described in the above embodiments. Figure 3 This is a flowchart of a method for stabilizing the tension of a ribbon in a thermal transfer printer, provided by an embodiment of the present invention; as shown below. Figure 3 As shown, the method includes the following steps:

[0061] S110. During the initialization phase, the first drive component is controlled to be in motor mode and the second drive component is controlled to be in generator braking mode so that the ribbon travels forward a preset distance, and the first drive component is controlled to switch to generator braking mode and the second drive component is controlled to switch to motor module so that the ribbon travels backward a preset distance.

[0062] S120. Determine whether the preset distance is greater than the initial distance;

[0063] S130, If yes, then enter the thermal printing stage, control the first drive component to switch to motor mode and the second drive component to switch to generator braking module to make the ribbon travel forward thermal printing distance, and control the first drive component to switch to generator braking mode and the second drive component to switch to motor module to make the ribbon travel backward thermal printing.

[0064] In this solution, during the thermal printing initialization and thermal printing stages, the ribbon remains stable because the two driving components move in opposite directions and not in a synchronous direction.

[0065] Based on the above embodiments, the control process for motor mode and generator braking mode is further refined. Figure 4 This is a flowchart of a method for stabilizing the tension of a ribbon in a thermal transfer printer, provided by an embodiment of the present invention; as shown below. Figure 4 As shown, the method includes the following steps:

[0066] S210. During the initialization phase, according to the first rotation command, pulse current is output to each of the first stator coils in the first drive assembly, and each of the first control switches is controlled to be disconnected so that the first drive assembly is in motor mode; and according to the second braking command, pulse current is not output to each of the second stator coils in the second drive assembly, and at least one second control switch is controlled to be opened at a second variable switching frequency so that the second drive assembly is in generator braking mode.

[0067] Specifically, refer to Figure 2 The first drive assembly 10 includes at least two-phase first stator coils 11, a first rotor 12, at least one first damping resistor 13, and at least one first control switch 14; the maximum number of first damping resistors is the same as the number of first stator coils; the first damping resistor 13 and the first control switch 14 are connected in series; the first stator coil 11 is connected in parallel with the first damping resistor 13 and the first control switch 14. The second drive assembly 20 includes at least two-phase second stator coils 21, a second rotor 22, at least one second damping resistor 23, and at least one second control switch 24; the maximum number of second damping resistors is the same as the number of second stator coils 21; the second damping resistor 23 and the second control switch 24 are connected in series; the second stator coil 21 is connected in parallel with the second damping resistor 23 and the second control switch 24.

[0068] According to the first rotation command, pulse current is output to each of the first stator coils 11 in the first drive assembly 10, and each of the first control switches 14 is controlled to open, so that the first drive assembly 10 is in motor mode, thereby generating positive traction force; according to the second braking command, pulse current is not output to each of the second stator coils 21 in the second drive assembly 20, and at least one second control switch 24 is controlled to open at a second variable switching frequency, so that the second drive assembly 20 is in generator braking mode, thereby generating reverse braking force; thus, the stability of the ribbon tension is ensured in the initial stage.

[0069] It is understood that when the second drive component 20 is in the generator braking mode, at least one second control switch 24 needs to be opened at the second variable switching frequency. That is, all second control switches 24 can be opened at the same time to generate a large braking force, or one of the second control switches 24 can be opened at the second variable switching frequency to generate a certain braking force. In this embodiment, the number of second control switches 24 that are opened can be determined according to the actual braking force required, and no specific limitation is made here.

[0070] S220. Determine whether the preset travel distance of the ribbon is greater than the forward initialization distance;

[0071] S230, If so, then according to the first braking command, control not to output pulse current to each of the first stator coils in the first drive assembly, control at least one first control switch to open at the first variable switching frequency to switch the first drive assembly to the generator braking mode; and according to the second rotation command, output pulse current to each of the second stator coils in the second drive assembly, and control the second control switch to open to put the second drive assembly into motor mode.

[0072] In the process of switching from motor mode to generator braking mode, the first drive component can control the frequency of the first variable switch to be lower to ensure that the damping current changes less and can ensure smooth ribbon switching. After the switching is completed, the frequency of the first variable switch can be adjusted to be higher, so that the ribbon tension is greater. Similarly, in the process of switching from generator braking mode to motor mode, the second drive component can lower the frequency of the second variable switch in advance to ensure smooth ribbon switching.

[0073] S240. Determine whether the preset travel distance of the ribbon is greater than the reverse initialization distance;

[0074] S250, if so, then enter the thermal printing stage, output pulse current to each of the first stator coils in the first drive assembly according to the first rotation command, and control each of the first control switches to disconnect so that the first drive assembly switches back to motor mode; and control not to output pulse current to each of the second stator coils in the second drive assembly according to the second braking command, and control at least one second control switch to open at the second variable switching frequency so that the second drive assembly switches back to generator braking mode.

[0075] S260. Determine whether the preset travel distance of the ribbon is greater than the thermal printing distance;

[0076] S270, if so, then according to the first braking command, control not to output pulse current to each of the first stator coils in the first drive assembly, control at least one first control switch to open at the first variable switching frequency so that the first drive assembly is switched back to generator braking mode; and according to the second rotation command, output pulse current to each of the second stator coils in the second drive assembly, and control the second control switch to open so that the second drive assembly is switched back to motor mode until the ribbon travels the reverse thermal printing distance.

[0077] In this embodiment, the control process of motor mode and generator braking mode is further refined based on the composition of each drive component, thereby achieving stable control of ribbon tension at different thermal printing stages.

[0078] In addition, in this embodiment, while maintaining stable ribbon tension, the current on the second damping resistor or the first damping resistor can be received during the thermal printing initialization stage or the thermal printing stage; thereby, the ribbon tension on the ribbon can be detected in real time based on the current on the second damping resistor or the first damping resistor.

[0079] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, the scope of which is determined by the scope of the appended claims.

Claims

1. A thermal transfer printer ribbon tension stability control system characterized by, The application relates to a drive assembly for a thermal printer. The drive assembly comprises a first drive assembly, a second drive assembly and a control module; The first drive assembly is connected with the second drive assembly through a color band; The control module is connected with the first drive assembly and the second drive assembly through electric signals; the control module is used for controlling the first drive assembly to be in a motor mode and the second drive assembly to be in a power generation braking mode in an initialization stage so that the color band moves forward by a preset distance, and controlling the first drive assembly to be switched to the power generation braking mode and the second drive assembly to be switched to the motor mode so that the color band moves backward by the preset distance; It is judged whether the preset distance is greater than an initialization distance; If yes, a hot printing stage is entered, the first drive assembly is controlled to be switched to the motor mode again and the second drive assembly is controlled to be switched to the power generation braking mode again so that the color band moves forward by a hot printing distance, and the first drive assembly is controlled to be switched to the power generation braking mode again and the second drive assembly is controlled to be switched to the motor mode again so that the color band moves backward by the hot printing distance; The first drive assembly comprises at least two-phase first stator coils, a first rotor, at least one first damping resistor and at least one first control switch; the maximum number of the first damping resistors is the same as the number of the first stator coils; the first damping resistors and the first control switch are connected in series; the first stator coils are connected in parallel with the first damping resistors and the first control switch; The control module outputs pulse currents to each of the first stator coils in the first drive assembly according to a first rotation instruction, and controls each of the first control switches to be turned off so that the first drive assembly is in the motor mode; The control module controls no pulse current to be output to each of the first stator coils in the first drive assembly according to a first braking instruction, and controls at least one of the first control switches to be turned on at a first variable switch frequency so that the first drive assembly is in the power generation braking mode. The second drive assembly comprises at least two-phase second stator coils, a second rotor, at least one second damping resistor and at least one second control switch; the maximum number of the second damping resistors is the same as the number of the second stator coils; The second damping resistors and the second control switch are connected in series; the second stator coils are connected in parallel with the second damping resistors and the second control switch; 2. The thermal transfer printer ribbon tension stability control system of claim 1, wherein, The control module outputs pulse currents to each of the second stator coils in the second drive assembly according to a second rotation instruction, and controls the second control switch to be turned off so that the second drive assembly is in the motor mode; The control module controls no pulse current to be output to each of the second stator coils in the second drive assembly according to a second braking instruction, and controls at least one of the second control switches to be turned on at a second variable switch frequency so that the second drive assembly is in the power generation braking mode. ​ ​ ​ The control module controls not to output pulse current to each of the second stator coils in the second drive assembly according to a second braking instruction, and controls at least one of the second control switches to be opened at a second variable switching frequency so that the second drive assembly is in the power generation braking mode.

3. The thermal transfer printer ribbon tension stability control system of claim 2, wherein, The control module comprises a first controller and a second controller; The first controller is configured to control the first drive assembly or the second drive assembly to be in the motor mode. The second controller is configured to control the first drive assembly or the second drive assembly to be in the power generation braking mode.

4. The thermal transfer printer ribbon tension stability control system of claim 2, wherein, The control module further comprises a tension determination unit; The tension determination unit is configured to detect the ribbon tension on the ribbon according to the current on the first damping resistor or the second damping resistor.

5. A method of stable control of the tension of a ribbon of a thermal transfer printer, characterized by, The thermal transfer printer ribbon tension stable control method comprises: In the initialization stage, the first drive assembly is controlled to be in the motor mode and the second drive assembly is controlled to be in the power generation braking mode so that the ribbon is positively driven for a preset distance, and the first drive assembly is controlled to be switched to the power generation braking mode and the second drive assembly is controlled to be switched to the motor mode so that the ribbon is reversely driven for the preset distance; It is judged whether the preset distance is greater than an initialization distance; If yes, the thermal printing stage is entered, the first drive assembly is controlled to be switched to the motor mode again and the second drive assembly is controlled to be switched to the power generation braking mode again so that the ribbon is positively driven for a thermal printing distance, and the first drive assembly is controlled to be switched to the power generation braking mode again and the second drive assembly is controlled to be switched to the motor mode again so that the ribbon is reversely driven for the thermal printing distance.

6. The thermal transfer printer ribbon tension stability control method according to claim 5, characterized by, The first drive assembly is controlled to be in the motor mode, specifically: Pulse current is output to each of the first stator coils in the first drive assembly according to a first rotation instruction, and each of the first control switches is controlled to be turned off so that the first drive assembly is in the motor mode; The first drive assembly is controlled to be in the power generation braking mode, specifically: Pulse current is not output to each of the first stator coils in the first drive assembly according to a first braking instruction, and at least one of the first control switches is controlled to be opened at a first variable switching frequency so that the first drive assembly is in the power generation braking mode.

7. The thermal transfer printer ribbon tension stable control method according to claim 6, wherein The second drive assembly is controlled to be in the motor mode, specifically: Pulse current is output to each of the second stator coils in the second drive assembly according to a second rotation instruction, and the second control switches are controlled to be turned off so that the second drive assembly is in the motor mode; The second drive assembly is controlled to be in the power generation braking mode, specifically: Pulse current is not output to each of the second stator coils in the second drive assembly according to a second braking instruction, and at least one of the second control switches is controlled to be opened at a second variable switching frequency so that the second drive assembly is in the power generation braking mode.

8. The thermal transfer printer ribbon tension stability control method according to claim 7, characterized by, Further comprising: receiving a current on the first damping resistor or on the second damping resistor; detecting a ribbon tension on the ribbon from the current on the first damping resistor or on the second damping resistor.

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