Small thermal transfer printer

Abstract

The application discloses a small thermal transfer printer capable of effectively improving the space utilization rate in a machine shell. A main control circuit board assembly and a printing head assembly are arranged on two sides of a ribbon corresponding to a printing position. The printing head assembly and the main control circuit board are respectively arranged on two sides of a ribbon cartridge. Elastic touch pressure type printing head electromechanical contact elements and circuit board electromechanical contact elements are arranged to electrically connect the wire harnesses of the printing head assembly and the main control circuit board with the printing head electromechanical contact elements and the circuit board electromechanical contact elements. The printing head electromechanical contact elements and the circuit board electromechanical contact elements are elastically connected to realize the electrical connection between the printing head assembly and the main control circuit board. The conductive performance is stable, long and multiple power supply wires arranged in a narrow space are avoided, the small thermal transfer printer is miniaturized, and after printing, the machine cover is automatically popped up upward under the elastic effect of the elastic touch pressure type printing head electromechanical contact elements and / or the circuit board electromechanical contact elements in the moment when the machine cover is opened.

Description

Technical Field

[0001] This invention relates to thermal transfer printers, and more particularly to a thermal transfer printer that can make full use of the space inside the casing. Background Technology

[0002] Existing small thermal transfer printers include a housing, a printhead assembly, a ribbon cartridge assembly, a printing roller, a main control circuit board, and a power battery, all housed within the housing. The housing further includes a cover and a base, with the ribbon cartridge assembly positioned between the printhead assembly and the printing roller.

[0003] To ensure the printer remains stable on the workbench during use without tipping over, the total weight of all components within the base must be sufficient to keep the printer's center of gravity within the base even when the cover is open. Heavier components, such as the power battery and main control circuit board, are typically housed within the base. There are two methods for mounting the printhead:

[0004] 1. A type of printer in which the printhead assembly, power battery, and main control circuit board are all located inside the base, and the printing roller is located on the cover (e.g., Chinese Invention Patent, Patent No.: CN202011054431.8, Publication Date: 2022.01.28, Title: A Thermal Transfer Printer).

[0005] This structure has the following shortcomings:

[0006] 1) Assembling heavier and larger components inside the base results in the underutilization of space inside the cover, making it difficult to miniaturize the size of this type of printer.

[0007] 2) Because the print head's heating element is facing upwards, if there is some dust on the printing medium during use, this dust will fall onto the surface of the print head. Large dust particles can easily scratch the print head during printing, especially when used outdoors.

[0008] 3) The drive unit that drives the printing roller and the transmission mechanism between the printing roller occupy a large amount of internal space.

[0009] 2. Another type has the printing roller, power battery, and main control circuit board all located inside the machine base, while the print head assembly is located on the machine cover.

[0010] This structure has the following shortcomings:

[0011] 1) The wiring harness (including power supply wires and signal wires) that controls the operation of the heating wires of the printhead assembly needs to be electrically connected to the main control circuit board through a male and female connector structure. This wiring harness needs to be connected to the circuit board through the cover and the base. Additional parts are needed to complete the above functions, which greatly increases the size and structural complexity.

[0012] 2) The wiring harness (including power supply wires and signal wires) that controls the operation of the heating wires of the printhead assembly is concentrated together and has a large diameter. If the wiring is connected by running the wires from top to bottom inside the casing, it will hinder the normal operation of some components inside the casing. If the wires are run through the hinge shaft connecting the cover and the base, the diameter of the hinge shaft is large, which increases the size of the machine and makes it impossible to achieve miniaturization. Summary of the Invention

[0013] The technical problem to be solved by the present invention is to provide a small thermal transfer printer that can effectively improve the utilization rate of internal space.

[0014] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0015] The present invention relates to a small thermal transfer printer, comprising a main control circuit board assembly, a printhead assembly, and an ink ribbon, characterized in that: the main control circuit board assembly and the printhead assembly are respectively disposed on both sides of the ink ribbon corresponding to the printing position.

[0016] The printhead assembly includes one or more printhead electromechanical contacts, and the printhead wiring harness connected to the printhead is connected to the printhead electromechanical contacts. The main control circuit board assembly includes one or more circuit board electromechanical contacts, and the circuit board wiring harness connected to the main control circuit board is connected to the circuit board electromechanical contacts. When the printhead is pressed onto the printing roller by the ribbon, the printhead electromechanical contacts and the corresponding circuit board electromechanical contacts are electrically connected in an elastic compression contact manner.

[0017] Both the printhead electromechanical contact and the circuit board electromechanical contact are elastic conductive posts, or one of the printhead electromechanical contact and the circuit board electromechanical contact is an elastic conductive post and the other is a fixed conductive contact.

[0018] The elastic conductive column consists of a conductive column cavity, a compression spring placed inside the conductive column cavity, and a conductive column. The compression spring is placed inside the conductive column cavity and is located between the top end of the conductive column and the top surface inside the conductive column cavity. The conductive column is in contact with the inner wall of the conductive column cavity and can move up and down inside the conductive column cavity.

[0019] The conductive contact is shaped as a planar or curved surface depression.

[0020] Two modules, each consisting of multiple printhead electromechanical contacts and a corresponding number of circuit board electromechanical contacts, are respectively located on the left and right sides of the printer. In each module, multiple conductive channels consisting of multiple printhead electromechanical contacts and circuit board electromechanical contacts are power supply connection channels or electrical signal transmission channels, or a portion of them are power supply connection channels and another portion are electrical signal transmission channels.

[0021] There is a power compartment on each side inside the printer housing. Each power compartment is equipped with a back panel and a cover panel. The inner side of the back panel and the outer side of the cover panel are fastened together to form a box with a hollow cavity. The circuit board electromechanical contact assembly is set on the top panel of the cover panel.

[0022] The printhead assembly is mounted on the inner surface of the printer's cover, the main control circuit board is mounted inside the printer's base, and the circuit board wiring harness passes downward through the housing and is electrically connected to the main control circuit board.

[0023] A switch hole is provided at each end of the cover, and an elastic latch is provided in the switch hole. Correspondingly, a lock hole is provided on the back panel of the compartment. When the latch of the elastic latch is engaged in the lock hole, it fastens the cover to the base. At the same time, the elastic conductive pin is pressed into the corresponding conductive contact. At the moment when the latch moves out of the lock hole, the cover pops up on the opening side under the action of the compression spring.

[0024] The cover is hinged to the base, and the diameter of the hinge shaft is between 0.8mm and 2.5mm.

[0025] This invention mounts the printhead assembly and the main control circuit board on opposite sides of the ribbon cartridge. By incorporating elastic, pressure-sensitive printhead electromechanical contacts and circuit board electromechanical contacts, the wiring harnesses supplying the printhead assembly and main control circuit board are electrically connected to these contacts. During printing, the printhead and circuit board contacts elastically connect to achieve electrical connection between the printhead assembly and the main control circuit board. This provides stable conductivity, avoiding the need for long and numerous conductive wires in a confined space, thus facilitating the miniaturization of the thermal transfer printer. Furthermore, after printing, the cover automatically pops upwards the instant it is opened, due to the elastic action of the elastic printhead and / or circuit board electromechanical contacts. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the thermal transfer printer of the present invention.

[0027] Figure 2 To open Figure 1 A diagram showing the back of the printer's cover.

[0028] Figure 3 To be Figure 2 A schematic diagram of the ribbon cartridge assembly after it has been removed.

[0029] Figure 4 for Figure 1 A schematic diagram showing the machine after the cover, base, and ribbon cartridge components have been removed.

[0030] Figure 5for Figure 4 A schematic diagram showing the paper feed path after the support plate and feed roller have been removed.

[0031] Figure 6 for Figure 1 A schematic diagram of the main internal components of a printer.

[0032] Figure 7 for Figure 6 A diagram showing the view from below.

[0033] Figure 8 for Figure 6 An explosion diagram.

[0034] Figure 9 for Figure 7 An explosion diagram.

[0035] Figure 10 for Figure 6 A diagram illustrating the printhead descending and pressing against the ribbon.

[0036] Figure 11 for Figure 10 A diagram showing the removal of the ear clip plate.

[0037] Figure 12 for Figure 6 This is a diagram showing the printhead being lifted and released from pressure on the ribbon.

[0038] Figure 13 for Figure 12 A diagram illustrating the removal of the ear clip plate.

[0039] Figure 14 for Figure 5 A schematic diagram of its breakdown.

[0040] Figure 15 for Figure 5 Right side view of the right power compartment.

[0041] Figure 15a for Figure 15 An enlarged schematic diagram.

[0042] Figure 15b for Figure 15a A schematic diagram after the power compartment has been removed.

[0043] Figure 16 for Figure 15 An exploded view of the right power compartment.

[0044] Figure 17 for Figure 5 Left side view of the left power compartment.

[0045] Figure 17a for Figure 17 An enlarged schematic diagram.

[0046] Figure 17b for Figure 17a A schematic diagram after the power compartment has been removed.

[0047] Figure 18 for Figure 17 An exploded view of the left power compartment.

[0048] Figure 19 for Figure 2 A schematic diagram from another perspective.

[0049] Figure 20 for Figure 19 A schematic diagram of its breakdown.

[0050] Figure 21 for Figure 20 A schematic diagram showing the combination of the power compartment, ribbon cartridge assembly, and engine cover.

[0051] Figure 22 for Figure 21 A schematic diagram showing the ribbon cartridge assembly assembled with the power compartment.

[0052] Figure 23 for Figure 22 A schematic diagram of its breakdown.

[0053] Figure 24 for Figure 22 A schematic diagram showing the separation of the middle color ribbon box assembly from the power compartment.

[0054] Figure 25 for Figure 22 A schematic diagram of the ribbon cartridge assembly combined with the power compartment.

[0055] Figure 26 for Figure 1 A plan view of the front side of the printer.

[0056] Figure 27 for Figure 26 A sectional view along the AA direction.

[0057] Figure 28 for Figure 1 A diagram showing the printer with its cover just opened.

[0058] The attached figures are labeled as follows:

[0059] Printer 1, Housing 11, Cover 12, Base 13, Side Cover 14 、 15 feed rollers 、 Elastic pressure component 16 、 Support plate 17, printing roller 18 、Printhead 21, Print base plate 22, Ear holder plate 23, Ribbon cassette 3, Base plate 31, Unwind cassette 32, Rewind cassette 33, Ribbon unwinding shaft 34, Ribbon 35, Power compartment 4, Compartment back plate 41, Compartment cover plate 42, Cartridge body 43, Ear plate window 44, First power compartment 45, First motor 451, First power transmission mechanism 452, Second power compartment 46 、 Second motor 461, second power transmission mechanism 462, transmission shaft 47, lifting connecting rod plate 5, support rod shaft 51, eccentric cam 52, drive end 53, lifting end 54 、 Printhead electromechanical contact 61, circuit board electromechanical contact 62, elastic conductive post 63, conductive post cavity 64, compression spring 65, conductive post 66, conductive contact 67, switch hole 71, lock hole 72, elastic latch 73, lever 74, moving plate 75, locking tongue 76, reset spring 77, limit baffle 78, damping component 81, cover plate 82, 82, window hole 83, upper recess 84, lower recess 85. Detailed Implementation

[0060] like Figure 1-3 , Figures 6-13 As shown, the small thermal transfer printer 1 of the present invention (hereinafter also referred to as printer 1) has external dimensions of (220mm-320mm)×(50mm-75mm)×(40mm-57mm) with length×width×thickness, preferably 317mm×73.6mm×51.5mm with length×width×thickness; its weight is 500g-1000g, preferably 800g, and the printing width of the printing medium is 220mm-260mm. Because this invention is compact, lightweight, and has a large effective printing width with a width utilization rate of up to 82% (formula: printing width of printing medium 260 / external dimensions 317 * 100%), while the existing small thermal transfer printers (see Chinese Invention Patent, patent number: CN202011054431.8) have a width utilization rate of only 67% (formula: printing width of printing medium 210 / external dimensions 310 * 100%), it is a printer that is highly valued by personnel who often need to print blank printing media on-site when working outdoors.

[0061] The printing medium referred to in this invention is a paper label printing medium with self-adhesive paper, or a soft plastic thin card printing medium with an easily stickable ribbon 35, or a thin metal sheet / plate sign printing medium with an easily hookable ribbon 35.

[0062] The small thermal transfer printer 1 of the present invention is particularly suitable for printing on printing media such as single labels, single aluminum-plastic labels or single signs with self-adhesive paper when on-the-go workers in the fields of power, communications, petrochemicals and transportation need to make and replace power signs and traffic signs on the go.

[0063] The printer 1 of the present invention has the following improvements over the small thermal transfer printer 1 in the prior art:

[0064] 1. A paper feed roller 15 is provided between the paper inlet of printer 1 and the print head 21. This facilitates the entry of printing media into the paper feed channel and allows the printing media entering the paper feed channel to move smoothly and at a constant speed to the printing position while controlling the travel speed.

[0065] 2. The printhead 21 is configured as a liftable structure. This liftable structure allows the printhead 21 to rise a small distance before the printing medium is conveyed to the printing position. This allows the ribbon 35, which is pressed downward by the heating wire of the printhead 21, to rebound under the tension of the ribbon 35 material and move away from the printing roller 18 located below the printhead 21 (preferably, the height of the ribbon 35 away from the printing roller 18 should be higher than the upper surface of the printing medium before it reaches the printing position). This creates height space for the printing medium to smoothly enter the printing position (directly below the printhead 21). In other words, the printing medium does not enter the printing position by the rolling action of the printing roller 18 (i.e., the "paper feed roller 15" mentioned in the background art), the ribbon 35, and the printhead 21. Instead, it is easily pushed into the printing position by the paper feed roller 15 and the printing roller 18 together when there are no obstacles above the printing medium. This structure can effectively prevent printing failures such as the ribbon 35 being scratched or pulled out due to a small amount of adhesive seeping from the front edge of the printing medium (the position on the printing medium that first enters the paper feed) or irregular front edge (with burrs or a slightly curved front edge) sticking to the ribbon 35.

[0066] Once the printing media has successfully entered the printing position, the print head 21 drops down and presses the ribbon 35 and the printing media against the printing roller 18 for normal printing.

[0067] 3. In order to make the above-mentioned printing media travel more smoothly in the paper feeding channel and avoid its leading edge being blocked (the reason for the blockage is the "sticking" between it and the ribbon 35 mentioned above), the paper feeding channel is set as a rigid paper feeding channel, which is composed of an upper limit plate and a lower limit plate made of rigid material.

[0068] 4. This invention features an independent paper feeding mechanism (i.e., paper feeding roller 15) and an independent printhead 21 lifting mechanism, allowing the printhead 21 to no longer press against the print roller 18 when printing is not required. When printing is needed, the independent paper feeding mechanism feeds the printing medium into the printing position below the printhead 21. The printhead 21 then lowers and presses the ribbon 35 to be printed onto the printing medium and the print roller 18. The printer 1 drives the print roller 18 to complete the printing of the current color. Afterward, the printhead 21 rises and moves away from the print roller 18. The paper feeding mechanism then recycles the printed medium and feeds it back into the printing position. The printhead 21 then presses the ribbon 35 of another color to be printed onto the printing medium and the print roller 18, driving the print roller 18 to complete the printing of the other color. This process can be repeated multiple times to achieve multi-color overprinting.

[0069] In addition, multi-color overprinting can be completed without the printing media fed into the paper path being sent out. Specifically, after printing one color, the print head 21 is raised, and the printing media retraction drive is activated to retract the printing media to the initial printing position. At this time, different colors on the same ribbon 35 are above the printing position. The print head 21 is lowered to press the ribbon 35 corresponding to that color onto the printing media for printing that color.

[0070] The present invention will now be described in detail with reference to the accompanying drawings:

[0071] I. Printer 1's casing 11

[0072] like Figure 1-3 As shown, the housing 11 consists of a cover 12, a base 13, and two side covers 14 on the left and right sides, as follows. Figure 2 , Figure 6-9 As shown, the printhead 21, ribbon cartridge assembly, paper feed roller 15, printing roller 18 and paper feed channel are arranged in a cavity formed by the cover 12, the base 13 and two side covers 14. The cover 12 is connected to the base 13 by a single-sided hinge. The diameter of the hinge shaft is 0.8mm-2.5mm, preferably 2.0mm.

[0073] The power transmission mechanism that controls the lifting and lowering of the print head 21, the winding of the ribbon cartridge 3, and the rotation of the paper feed roller 15 and the printing roller 18 is centrally located in the power chambers 4 on the left and right sides of the base 13 inside the housing 11.

[0074] The paper feeding path is horizontally set, which, compared with the inclined paper feeding path in the prior art, allows the paper feed roller 15 and the printing roller 18 to be set in the same plane, improving the utilization rate of the internal space and providing a basis for further miniaturization of the printer 1. The paper feed port and paper output port of the paper feeding path are respectively set on the front and rear sides of the housing 11 (the paper feed port is located at the front of the housing 11, and the paper output port is located at the rear of the housing 11), preferably at the joint after the cover 12 and the base 13 are fastened together.

[0075] The casing 11 of the present invention is preferably made of plastic or aluminum alloy.

[0076] II. Paper feed roller 15

[0077] like Figure 6-9 As shown, the present invention preferably places the paper feed roller 15 at the paper feed inlet, and provides an elastic pressing component 16 above it to further help the printing medium enter the paper feed channel quickly. The elastic pressing component 16 is a freely rotatable upper roller, pressing plate or pressing shaft.

[0078] The drive unit for driving the paper feed roller 15 can be a separate motor, or it can be connected to the drive unit for driving the printing roller 18 via a gear transmission mechanism. The power transmission components that drive the paper feed roller 15 and the printing roller 18 are centrally located in the power chamber 4.

[0079] III. Rigid Paper Feeding Channel

[0080] In order to ensure that the aforementioned printing media with self-adhesive or ultra-thin metal sheets / plates can reach the printing position smoothly, the present invention sets the paper feeding channel as a rigid paper feeding channel. Specifically, a channel composed of an upper limit plate and a lower limit plate made of rigid material is set from the paper inlet of the printer 1 to below the print head 21 and between the ribbon 35 and the printing roller 18.

[0081] In this invention, the upper limit plate is preferably the base plate 31 of the ribbon cartridge 3, and the lower limit plate is the support plate 17 that supports the printing medium in the paper feeding channel.

[0082] The gap between the upper limit plate and the lower limit plate is 1.0mm-5.0mm.

[0083] Ideally, a rigid paper feed path should extend from the paper inlet to the paper outlet.

[0084] IV. Ribbon Cartridge Assembly

[0085] The unwind cassette 32 and the rewind cassette 33 each include a housing, a roll, and an unwind ribbon 35 (a new ribbon 35 without printed content) or a rewind ribbon 35 (a recycled ribbon 35 with printed content) wound on the corresponding roll. The unwind cassette 32 and the rewind cassette 33 are arranged horizontally at intervals, located on the front and rear sides of the base 13 respectively. The ribbon 35 is output from the unwind cassette 32, passes under the print head 21, and is retrieved by the rewind cassette 33. The power transmission component that drives the rewind roll to rotate is located in the power chamber 4.

[0086] To prevent the unwinding drum from slackening due to changes in linear velocity when outputting the ribbon at 35°, the present invention provides an unwinding damping component 81 on the unwinding drum.

[0087] V. Printing roller 18

[0088] The power transmission component that drives the rotation of the machine is located in the power chamber 4 and is situated within the base 13 and below the gap between the unwinding box 32 and the rewinding box 33.

[0089] VI. Printhead Assembly

[0090] like Figure 8-13 As shown, the assembly includes a printing plate (also called a printhead support) 22, a printhead 21 mounted on the printing plate 22, and ear plates 23 disposed on the left and right sides of the printing plate 22. The printhead 21 is set at a certain angle with the support plate 17 between the printing roller 18 and the paper feed roller 15. The angle is 8°-15°. The printing line (also called the heating line) is located at the bottom of the printhead 21. The ear plates 23 are in the shape of an inverted "U". When the printhead assembly is installed in the housing 11, the left and right ear plates 23 are respectively locked at the left and right ends of the roller shaft of the printing roller 18.

[0091] The lifting mechanism that drives the print head 21 to rise and fall is located in the power chamber 4. It consists of a lifting linkage plate 5, a support rod shaft 51, and an eccentric cam 52. The lifting linkage plate 5 is an integral structure with a shape approximately “Z”. It is mounted on the chamber wall of the power chamber 4 via the support rod shaft 51.

[0092] The lifting linkage plate 5 is divided into a driving section at the front and a lifting section at the rear, with the support rod shaft 51 as the boundary. The end of the driving section (called the driving end 53) is preferably located near the paper inlet, and the end of the lifting section (called the lifting end 54) is located below the end of the roller shaft of the printing roller 18 and is vertically opposite to the ear plate 23.

[0093] A return spring is provided on the lifting connecting rod plate 5 to reset the lifting connecting rod plate 5 when the lifting end 54 falls. The return spring can be a torsion spring or a tension spring, with a torsion spring being preferred.

[0094] The eccentric cam 52 is disposed above or below the drive end 53. In this invention, it is preferably disposed above the drive end 53. The motor that drives the eccentric cam 52 to rotate is disposed outside the power chamber 4 and below the paper feed roller 15 inside the base 13. The lifting end 54 is a double fork plate with a "U" shaped notch.

[0095] When the eccentric cam 52 drives the drive end 53 to move downward, the double fork plate exerts upward force on the ear buckle plate fastened to the end of the roller shaft of the printing roller 18 and lifts the print head 21 to disengage from the pressure on the ribbon 35.

[0096] VII. Power Compartment

[0097] like Figures 1-5 , Figures 14-18 As shown, the housing 11 is composed of a cover 12, a base 13 and two side covers 14 on the left and right sides. The housing 11 contains a main control circuit board, a battery power supply, a printhead assembly, a ribbon cartridge assembly and a printing roller 18.

[0098] Its characteristic is that there is a power chamber 4 on each of the left and right sides inside the housing 11, namely the first power chamber 45 and the second power chamber 46, and the print head assembly, ribbon cartridge assembly and printing roller 18 are located between the two power chambers 4.

[0099] Each power compartment 4 of the present invention is preferably composed of a back panel 41 and a cover panel 42. The inner side of the back panel 41 (inner side pointing to the inside of the housing 11 and outer side pointing to the outside of the housing 11) and the outer side of the cover panel 42 are fastened together to form a box 43 with a hollow cavity.

[0100] The two power compartments 4 are preferably an integral structure made by injection molding, with the bottom end of the box 43 being open; or the two power compartments 4 are composed of a compartment back plate 41 and a compartment cover plate 42 connected by snaps, screws or adhesive.

[0101] 1. First power compartment 45

[0102] The first power transmission mechanism 452 is used to install the first power transmission mechanism 452 and the drive device (hereinafter referred to as the first motor 451) that drives the first power transmission mechanism 452 to operate. The first motor 451 drives the ribbon cartridge assembly and the printing roller 18 through the first power transmission mechanism 452. The first power transmission mechanism 452 is centrally located in the first power chamber 45 and forms a standardized module. The power transmission performance, operational reliability and stability of the standardized module can be independently tested before it is assembled into the printer 1.

[0103] The power input terminals of the ribbon cartridge assembly and the printing roller 18 are directly connected to the corresponding power output terminals in the first power transmission mechanism 452 via snap-fit, gear meshing, or male-female mating.

[0104] The present invention also provides a paper feed roller 15 on the paper feed side of the printer 1. The paper feed roller 15 rotates synchronously with the printing roller 18. Its power input end is connected to the corresponding power output end in the first power transmission mechanism 452 by means of snap-fit, gear meshing or male-female mating.

[0105] The first motor 451 is installed on the inner side of the back plate 41 of the first power compartment 45, and the gear set in the first power transmission mechanism 452 is installed on the outer side of the back plate 41 of the first power compartment 45.

[0106] The ribbon 35 take-up spool in the ribbon cartridge assembly is directly connected to the corresponding power output terminal of the first power transmission mechanism 452 via a clutch assembly. This clutch assembly engages the ribbon 35 take-up spool with the first power transmission mechanism 452 during printing by the print head 21, and disengages the ribbon 35 take-up spool from the first power transmission mechanism 452 when printing is complete and the print head 21 is raised. For a detailed technical description of the clutch assembly, please refer to the national invention patent application filed by the applicant on January 17, 2024 (title: Thermal transfer printer 1 and ribbon 35 take-up drive mechanism assembled therein, application number: 202410069406.9).

[0107] The clutch component of the clutch assembly is installed inside the housing 43 of the first power compartment 45.

[0108] 2. Second power compartment 46

[0109] The second power transmission mechanism 462 is used to install the drive device (hereinafter referred to as the second motor 461) that drives the second power transmission mechanism 462 to operate. The second motor 461 drives the lifting mechanism of the print head 21 in the print head assembly to rise or fall through the second power transmission mechanism 462. Similarly, the second power transmission mechanism 462 is centrally located in the second power chamber 46 and forms a standardized module. The power transmission performance, operational reliability and stability of the standardized module can be independently tested before it is assembled in the printer 1.

[0110] The lifting mechanism consists of two sets, each installed in a corresponding housing 43 within one of the two power compartments 4. The power transmission between the two sets of lifting mechanisms is connected via a transmission shaft 47. The power input end of the lifting mechanism is plugged into and connected to the corresponding power output end of the second power transmission mechanism 462 via a snap-fit, gear engagement, or male-female mating method.

[0111] The second motor 461 is installed on the inner side of the back plate 41 of the second power compartment 46, and the second gear set in the second power transmission mechanism 462 is installed on the outer side of the back plate 41 of the second power compartment 46 and connected to the power output shaft of the second motor 461.

[0112] The first motor 451 and the second motor 461 are arranged opposite each other and are located in the installation space provided by the lower side of the cover plate 42 on the corresponding side.

[0113] The lifting mechanism consists of a lifting connecting rod plate 5, a support rod shaft 51, and an eccentric cam 52. The lifting connecting rod plate 5 is an integral structure that is rotatably sleeved on the support rod shaft 51. The support rod shaft 51 is installed in the corresponding box 43 between the back plate 41 and the cover plate 42.

[0114] The lifting linkage plate 5 is an integral structure, which can be divided into a drive section, a balance section, and a lifting section. The end of the drive section is called the drive end 53, the balance section is called the balance plate, and the end of the lifting section is called the lifting end 54. The balance plate is connected to the support rod shaft 51. The drive end 53 and the lifting end 54 are respectively located on the front and rear sides of the balance plate. A return spring that allows the lifting end 54 to fall is fastened to the lifting linkage plate 5. The eccentric cam 52 is located on the side of the drive end 53 and contacts the drive end 53. The ear plates 23 located on the left and right sides of the print head 21 bracket are located on the side of the lifting end 54. Under the rotation of the eccentric cam 52, the drive end 53 and the lifting end 54 move in opposite directions, one up and one down.

[0115] The top surface of the cover plate 42 is provided with an ear plate window 44. When the second motor 461 drives the eccentric cam 52 to rotate to the point where the convex part faces upward through the two-speed gear set, the drive end 53 moves upward under the action of the return spring. At this time, the print head 21 descends, and the lower end of the ear plate 23 can pass through the ear plate window 44 and be mounted on the end of the roller shaft of the printing roller 18 and is vertically opposite to the lifting end 54. When the second motor 461 drives the drive end 53 to move downward, the lifting end 54 moves upward and lifts the ear plate 23. At this time, the print head 21 moves upward and is released from the pressure of the ribbon 35 below it.

[0116] Preferably, the drive end 53 is located on the paper inlet side, the eccentric cam 52 is positioned above the drive end 53, and the lifting end 54 is a double-forked plate with a "U"-shaped notch. Correspondingly, the ear plate 23 is also preferably the same shape as the lifting end 54, i.e., a double-forked plate with a "U"-shaped notch. When the lifting end 54 moves upward, the double-forked plate of the lifting end 54 exerts upward force on the ear plate 23, which is fastened to the end of the printing roller 18, and lifts the print head 21 upward.

[0117] Inside the housing 43, there is also a photoelectric sensor that can detect the position of the lifting end 54 when it rises. Based on this setting, the height of the lifting end 54 can be adjusted.

[0118] The present invention installs the first motor 451 and the first power transmission mechanism 452, the second motor 461 and the second power transmission mechanism 462 respectively in the first power chamber 45 and the second power chamber 46 to form a standardized module whose power transmission effect, operational reliability and stability can be tested offline. Moreover, compared with the prior art, it can print a wider printing medium with the same width size. For example, the existing small thermal transfer printer 1 with an external width of 310mm can print a medium with a width of 210mm, while the present invention can print a medium with a width of 260mm, which improves the width utilization rate by 15% (82%-67%=15%).

[0119] 8. Electrical connection between printhead assembly and main control circuit board

[0120] like Figures 1-3 , Figures 19-20 , Figures 26-28 As shown, it includes a main control circuit board assembly, a printhead assembly, a ribbon cartridge assembly, and a printing roller 18. One feature of this invention is that it improves the structure of the small thermal transfer printer 1 in the prior art, which often places the main control circuit board assembly and the printhead assembly in the bottom of the housing 11, by setting the two separately. One is set on the inner surface of the cover 12 of the printer 1, and the other is set in the bottom of the base 13 of the printer 1. The ribbon cartridge assembly is placed in the housing 11 and between the printhead assembly and the main control circuit board assembly when the cover 12 and the base 13 are fastened together. The printing roller 18 is placed between the ribbon cartridge assembly and the main control circuit board assembly.

[0121] The present invention preferably places the printhead assembly on the inner surface of the cover 12 of the printer 1, and places the main control circuit board and power battery in the main control circuit board assembly at the bottom of the base 13 of the printer 1. In this way, the space inside the casing 11 can be fully utilized, thereby facilitating the miniaturization of the printer 1.

[0122] After separating the two components, the arrangement of the power and signal lines (hereinafter referred to as wiring harnesses) between the printhead assembly and the main control circuit board assembly becomes a very challenging problem. Since the wiring harnesses are concentrated together and have a large diameter, if they are connected by vertical wiring within the housing 11, it will hinder the normal operation of some components within the housing 11. If the wiring is routed through the hinge joint connecting the cover 12 and the base 13, this connection method is not feasible due to the small diameter of the hinge joint (in this invention, which is a small printer 1, the diameter of the hinge joint is between 0.8mm and 2.5mm, preferably 2.0mm). Therefore, this invention adopts the following structure for electrically connecting the printhead assembly and the main control circuit board:

[0123] The printhead assembly includes one or more printhead electromechanical contacts 61, which are disposed beside the printhead. The printhead 21 wiring harness connected to the printhead 21 is connected to the printhead electromechanical contact 61. The main control circuit board assembly includes one or more circuit board electromechanical contacts 62, which are disposed beside the main control circuit board or on the main control circuit board. The circuit board wiring harness connected to the main control circuit board is connected to the circuit board contact. The number of printhead electromechanical contacts 61 and circuit board electromechanical contacts 62 are the same and they correspond one-to-one. The electrical connection between a printhead electromechanical contact 61 and a corresponding circuit board electromechanical contact 62 is referred to as the printhead main board electrical path (also known as a conductive path).

[0124] Preferably, the present invention provides multiple printhead mainboard electrical paths on one side of the printer. The rated conduction current of these printhead mainboard electrical paths can be the same or different. At the same time, these printhead mainboard electrical paths can be only power supply connection channels that provide power to the heating wires in the printhead assembly, or electrical signal transmission channels that provide 5V power and / or control signals to the sub-circuits in the printhead assembly. Alternatively, some can be power supply connection channels and others can be electrical signal transmission channels.

[0125] Preferably, the present invention comprises two modules consisting of multiple printhead mainboard electrical paths, which are respectively arranged on the left and right sides of the printer.

[0126] When the print head 21 is pressed onto the printing roller 18 by the ribbon 35, the print head electromechanical contact 61 and the corresponding circuit board electromechanical contact 62 are electrically connected in an elastic compression contact manner.

[0127] To achieve an electrical connection via elastic compression contact, the printhead electromechanical contact 61 and the circuit board electromechanical contact 62 can adopt the following two structures:

[0128] 1) Both the printhead electromechanical contact 61 and the circuit board electromechanical contact 62 are elastic conductive posts 63. The elastic conductive post 63 is composed of a conductive post cavity 64, a compression spring 65 placed in the conductive post cavity 64, and a conductive post 66. The compression spring 65 is placed in the conductive post cavity 64 and is located between the top end of the conductive post 66 and the top end surface inside the conductive post cavity 64. The conductive post 66 contacts the inner wall of the conductive post cavity 64 and can move up and down within the conductive post cavity 64.

[0129] When the printhead electromechanical contact 61 is connected to the circuit board electromechanical contact 62, the conductive posts 66 in both contacts elastically against each other, thereby achieving an electrical connection.

[0130] 2) One of the printhead electromechanical contact 61 and the circuit board electromechanical contact 62 adopts the elastic conductive post 63, and the other is a fixed conductive contact 67. The shape of the conductive contact 67 can be a plane or a concave pit with an arc surface. The present invention preferably adopts a concave pit with an arc surface.

[0131] When the printhead electromechanical contact 61 is connected to the circuit board electromechanical contact 62, the conductive post 66 in one part elastically abuts against the conductive contact 67 in the other part, thereby achieving electrical connection.

[0132] Preferably, the printhead electromechanical contact 61 is an elastic conductive post 63, and the circuit board electromechanical contact 62 is a conductive contact 67. Also preferably, the elastic conductive post 63 is disposed on the cover 12, and the conductive contact 67 is disposed on the left and right power chambers 4 inside the printer 1 housing 11.

[0133] Preferably, a cover plate 82 is provided on the inner surface of the cover 12 at a position opposite to the box body 43, and the elastic conductive post 63 is disposed on the cover plate 82; each power compartment 4 is composed of a compartment back plate 41 and a compartment cover plate 42, the inner side of the compartment back plate 41 and the outer side of the compartment cover plate 42 are fastened together to form a box body 43 with a hollow cavity, and the conductive contact 67 is disposed on the top panel of the compartment cover plate 42. The circuit board wiring harness passes downward through the box body 43 and is electrically connected to the main control circuit board.

[0134] The preferred locking mechanism between the cover 12 and the base 13 of the present invention adopts the following structure:

[0135] A switch hole 71 is provided at each end of the cover 12. An elastic buckle 73 is provided in the switch hole 71. Correspondingly, a lock hole 72 is provided on the back plate 41. When the locking tongue 76 of the elastic buckle 73 is engaged in the lock hole 72, it fastens the cover 12 to the base 13. At the same time, it presses the elastic conductive post 63 into the corresponding conductive contact 67.

[0136] The elastic latch 73 consists of a lever 74, a movable plate 75, a locking tongue 76, and a return spring 77. A sliding groove is provided on the inner surface of the cover 12 near the switch hole 71. The lever 74 is fixed to the upper surface of the movable plate 75 and is placed inside the switch hole 71. The movable plate 75 is placed on the inner surface of the cover 12 and can move back and forth along the sliding groove. The locking tongue 76 is located at the outer end of the movable plate 75. The return spring 77 is sleeved on a short shaft located at the inner end of the movable plate 75. A limiting baffle 78 is provided on the inner surface of the cover 12 to limit the return spring 77.

[0137] By manually moving the lever 74 inward, the locking tongue 76 moves out of the lock hole 72. At the moment the locking tongue 76 moves out of the lock hole 72, the opening side of the cover 12 automatically pops up and opens the cover 12 under the action of the compression spring 65 in the elastic conductive post 63.

[0138] Because of the use of the elastic conductive post 63, the present invention does not require a special elastic component for opening the cover 12.

[0139] IX. Damping Structure

[0140] like Figure 20-25 As shown, the damping structure of the present invention can ensure that the ribbon 35 is stretched. It is provided with a damping component 81 on the ribbon feeding shaft 34 at the ribbon 35 supply end of the ribbon cartridge 3, so that when the ribbon is fed, the ribbon 35 passes between the print head 21 and the printing medium in a straight and unfolded manner.

[0141] like Figures 1-3 As shown, power chambers 4 are provided on both sides of the housing 11 of the thermal transfer printer 1 using the ribbon cartridge 3. The top surface of the cover plate 42 of the power chamber 4 is provided with a downward recessed position 85. A cover plate 82 is provided on the inner side of the cover 12 of the thermal transfer printer 1 at a position opposite to the cover plate 42. An upward recessed position 84 is provided on the cover plate 82 at a position opposite to the downward recessed position 85.

[0142] The damping component 81 is preferably a torsion spring, which is mounted inside the housing 43 of the power compartment via a support shaft. When the ribbon cartridge 3 is installed inside the housing 11, the end of the ribbon feeding shaft 34 is confined within a shaft limiting hole formed by an upper recess 84 and a lower recess 85. A window 83 communicating with the housing 43 is provided on the concave wall of the lower recess 85. One torsion arm of the torsion spring presses against the outer wall of the ribbon feeding shaft 34, ensuring a constant elastic force that resists the ribbon feeding shaft 34. This prevents the ribbon 35 from wrinkling or curling when the ribbon 35 is pulled by the ribbon reel. Preferably, the upper end of the torsion arm is elastically exposed above the window 83 when the ribbon cartridge 3 is removed.

Claims

1. A small thermal transfer printer, comprising a main control circuit board assembly, a printhead assembly, and a ribbon (35), characterized in that: The main control circuit board assembly and the printhead assembly are respectively located on both sides of the ribbon (35) corresponding to the printing position; The printhead assembly is mounted on the inner surface of the cover (12) of the printer (1). The main control circuit board assembly includes a main control circuit board, which is mounted in the base (13) of the printer (1). The cover (12) and the base (13) are hinged together, and the diameter of the hinge axis is between 0.8mm and 2.5mm. The printhead assembly includes one or more printhead electromechanical contacts (61) disposed beside the printhead (21), and the printhead wiring harness connected to the printhead (21) is connected to the printhead electromechanical contact (61); the main control circuit board assembly includes one or more circuit board electromechanical contacts (62) disposed beside the main control circuit board or on the main control circuit board, and the circuit board wiring harness connected to the main control circuit board is connected to the circuit board electromechanical contact (62); the number of printhead electromechanical contacts (61) and circuit board electromechanical contacts (62) are the same and they correspond one-to-one; when the printhead (21) is pressed onto the printing roller (18) by the ribbon (35), the printhead electromechanical contact (61) and the corresponding circuit board electromechanical contact (62) are electrically connected by elastic compression contact; One of the printhead electromechanical contact (61) and the circuit board electromechanical contact (62) is an elastic conductive post (63), and the other is a fixed conductive contact (67); or, both the printhead electromechanical contact (61) and the circuit board electromechanical contact (62) are elastic conductive posts (63); a compression spring (65) is provided inside the elastic conductive post (63); A switch hole (71) is provided at each end of the cover (12), and an elastic latch (73) is provided in the switch hole (71). Correspondingly, a lock hole (72) is provided on the base (13). When the latch (76) of the elastic latch (73) is inserted into the lock hole (72), the cover (12) is tightly fastened to the base (13). At the same time, the elastic conductive post (63) is pressed into the corresponding conductive contact (67). At the moment when the latch (76) moves out of the lock hole (72), the cover (12) pops up on the opening side under the action of the compression spring (65).

2. The small thermal transfer printer according to claim 1, characterized in that: The elastic conductive post (63) consists of a conductive post cavity (64), a compression spring (65) placed in the conductive post cavity (64), and a conductive post (66). The compression spring (65) is placed in the conductive post cavity (64) and is located between the top end of the conductive post (66) and the top end surface inside the conductive post cavity (64). The conductive post (66) contacts the inner wall of the conductive post cavity (64) and can move up and down inside the conductive post cavity (64).

3. The small thermal transfer printer according to claim 1, characterized in that: The conductive contact (67) is a planar or arc-shaped depression.

4. The small thermal transfer printer according to claim 1, characterized in that: Two modules are formed by multiple printhead electromechanical contacts (61) and a corresponding number of circuit board electromechanical contacts, respectively located on the left and right sides of the printer (1); in each module, multiple conductive channels formed by multiple printhead electromechanical contacts (61) and circuit board electromechanical contacts (62) are power supply connection channels or electrical signal transmission channels, or a portion of them are power supply connection channels and another portion are electrical signal transmission channels.

5. The small thermal transfer printer according to claim 1, characterized in that: A power chamber (4) is provided on each side inside the casing (11) of the printer (1). Each power chamber (4) is provided with a back panel (41) and a cover panel (42). The inner side of the back panel (41) and the outer side of the cover panel (42) are fastened together to form a box (43) with a hollow cavity. The circuit board electromechanical contact (62) is provided on the top panel of the cover panel (42).

6. The small thermal transfer printer according to claim 5, characterized in that: The circuit board wiring harness passes downward through the box (43) and is electrically connected to the main control circuit board.

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