Thermal printer and method

Abstract

The present application relates to a thermal printer for printing on a print medium, comprising: a printhead (110, 110 ', 110' '), a printhead positioning device (120) for moving the printhead, a ribbon supply device comprising a print ribbon unwinder (150) and a ribbon rewinder (151), at least one roller (162). In operation, the printhead positioning device is configured to displace the printhead to at least three positions: a first position, applying a first amount of pressure to the print media, a second position, applying a second amount of pressure to the print media, and a third position wherein the printhead is spaced from the print media and does not apply pressure to the print media.

Description

Technical Field

[0001] The present application generally relates to apparatus in a printer. In a particular aspect, the present application relates to a thermal printer including an apparatus for controlling the position of a print head. The apparatus of the present application can be applied to general industrial printer applications, particularly label printers. Background Art

[0002] The demand for sustainable solutions is growing in the industrial printing market, especially for label printers and label applicators (Print & Apply). Thermal technology is commonly used to print labels, including self-adhesive labels. Thermal technology can be divided into two main sub-technologies: thermal direct technology and thermal transfer technology.

[0003] Thermal Direct technology uses thermal labels that change color, contrast or light reflectance when heated. The thermal printhead has an array of small heat elements that are used to expose, activate and modify the contrast of specific areas of the label as it passes over the printhead and vice versa.

[0004] Thermal transfer printing involves the use of a heat-sensitive ink ribbon that holds the ink, creating contrast. It also utilizes a thermal print head with an array of small heating elements to transfer the ink from the ribbon to the label.

[0005] Ink ribbons can be made up of several layers: a substrate, an ink layer, and a back coating. The substrate is usually made of polyester and provides support for the ribbon. The ink layer contains the actual ink, which is usually made up of wax, resin, or a combination of both. The back coating helps protect the printhead from damage and ensures smooth movement in the printer.

[0006] When printing, the ribbon is located between the print head and the print media. The printer applies heat to the print head, causing the ink on the ribbon to melt and transfer to the print media (such as paper or labels). The ink adheres to the print media to form a permanent image.

[0007] Thermal transfer printers are often used for applications that require high-quality, long-lasting prints, such as barcode labels, product packaging, and identification tags. Using ribbons can provide greater durability and resistance to environmental factors, making printouts more resistant to fading, moisture, and abrasion than direct thermal printing.

[0008] There are two main types of thermal printheads: near-edge printheads and flat-head printheads.

[0009] Near-edge printheads (sometimes called corner-edge printheads) have rows of heating elements located near the edge of the printhead. This allows for quick transfer of heat from the heating elements to the ribbon, allowing for high-speed printing. However, being near a corner makes the heating elements more exposed to debris. An ink ribbon helps protect the printhead. Near-edge printheads are less suitable for direct thermal applications. A significant advantage of near-edge printheads is that they can print at high speeds and can be removed from the label, keeping the ribbon at rest when not in use. This feature is often referred to as "ribbon saving."

[0010] Flat head printheads have rows of heating elements located farther away in the corners of the printhead, allowing the printhead to be angled more horizontally relative to the label than near edge printheads. Flat head printheads are generally more robust than near edge printheads, but they have lower top print speeds and require alignment with the drive roller within tighter tolerances to properly print the label. Flat head printheads may require precise alignment with the print / drive roller under the label to achieve good print quality. A significant advantage of flat head printheads is that they can be used for both thermal transfer and direct thermal applications.

[0011] 1 shows an exemplary printer 10 known in the prior art. The exemplary printer 10 may include an exemplary label printer 10 including a print head 11, a label supply spool 12 of label material mounted on a supply spool support 13, a take-up spool 14, an ink ribbon supply spool 15, an ink ribbon take-up spool 16, and a plurality of rollers 17, 18, and 19.

[0012] The label web extends from the supply spool 12 along a web path 20 , around roller 17 , along roller 19 , over drive roller 18 , around a label peeling nozzle 21 , and is wound onto the take-up spool 14 .

[0013] The ink ribbon extends from a supply spool 15, passes through 11 printing elements (not shown) of the print head and is wound onto a take-up spool 16. In this embodiment, the print head comprises a near edge print head. During the printing operation, the ink carried on the ribbon is transferred to the label to be printed. To achieve the transfer of ink, the print head contacts the ribbon, which contacts the label and is pressed against the drive roller 18. Summary of the invention

[0014] The present application proposes a method and device for processing the print head of a printer (especially an industrial printer) so as to save thermal printing ribbon and / or print head and / or print / drive roller during non-printing and / or service time.

[0015] Exemplary devices of the present application provide features such as lifting the printhead in multiple positions, providing accurate printhead alignment to ensure print quality regardless of printhead type over a full range of pressures, fast operation and accurate label delivery and ink ribbon delivery.

[0016] According to a first aspect, a thermal printer for printing on a print medium comprises: a print head, a print head positioning device for moving the print head, a ribbon feed device including a print ribbon unwinder and a ribbon rewinder, and at least one roller. In operation, the print head positioning device is configured to displace the print head to at least three positions: a first position, applying a first amount of pressure to the print medium, a second position, applying a second amount of pressure to the print medium, and a third position, wherein the print head is kept at a distance from the print medium and does not apply pressure to the print medium. In an exemplary embodiment, the print head positioning device is configured to apply the same pressure as the pressure applied to the print medium to a print ribbon configured to be substantially parallel to the print medium. In another example, the print head positioning device comprises a first arm, one end of which is connected to an actuator and a shaft that rotatably attaches the print head to a support structure, wherein the first arm is configured to displace the print head to the at least three positions. In one example, the first arm is mechanically and rotatably connected to the print head support structure so that the print head is located between the at least three positions. Therefore, the second arm is configured to apply a force to the print head support structure. In one example, the thermal printer may further include a sensor configured to provide a position of an actuator connected to the first arm upon activation. The memory may be arranged and configured to store a reference position, i.e., a fixed stop position of movement of the first arm. In one example, the second position printhead is adjacent to but a distance from a print ribbon between the print medium and the printhead.

[0017] According to a second aspect, a method for controlling the position of a print head in a thermal printer is provided. The thermal printer comprises: a print head positioning device for moving the print head, a print ribbon supply device comprising a ribbon unwinder and a ribbon rewinder, and at least one roller. The method comprises: moving the print head to at least three positions: a first position, applying a first amount of pressure on the print medium between the print head and the roller during a printing operation; a second position, applying a second amount of pressure on the print medium when a printing operation is not performed; a third position, wherein the print head maintains a distance from the print medium and does not apply pressure to the print medium. The method may include receiving information indicating the position of the print head at the first position, applying a predetermined force Fdot on the print head; at the first position, when a valid printing task ends, moving the print head to the second position; and optionally moving to the third position upon receiving an instruction. In one example, the rewinder is torque controlled in the first position and speed controlled in the third position. The method may also include:

[0018] In a first position, the web path is controlled by the roller so that the print head abuts the roller with a predetermined pressure; the length of the print media and the print media rewind diameter are measured; the print head is shifted to a second position during a print cycle but not actively printed based on the measured length and rewind diameter; and the label rewind speed is controlled, wherein the print media feed is at least assisted by the roller pushing the print media toward it during the print cycle. The first position is a printing position, the second position is a non-printing position, and the third position allows access to thermal printer components. In one example, the second position print head is adjacent to but at a distance from the print media and the print ribbon between the print head.

[0019] It will be apparent to a person skilled in the art that the above-mentioned aspects, the appended claims and / or the examples disclosed above and below may be appropriately combined with each other.

[0020] Additional features and advantages are disclosed in the following description, claims and drawings, and some features and advantages will be obvious to those skilled in the art or recognized by practicing the disclosure described herein. This article also discloses a control unit, a computer-readable medium and a computer program product related to the above technical advantages. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] With reference to the accompanying drawings, aspects of the present application cited as examples will be described in more detail below. With reference to the accompanying drawings, elements with the same reference numerals represent the same elements throughout.

[0022] FIG1 shows an exemplary printer according to the prior art;

[0023] Figure 2 shows a schematic side view of a printer comprising an exemplary apparatus according to the first aspect of the present application;

[0024] Figure 3 Shows Figure 2 A portion of the printer is in a first operating state;

[0025] Figure 4 Shows Figure 2 A portion of the printer is in a second operating state;

[0026] Figure 5 Schematic showing how the forces counteract each other to increase stiffness and print quality;

[0027] Figure 6 Shows Figure 2 The main view of the printer;

[0028] Figure 7 shows a schematic side view of a printer comprising an exemplary apparatus according to the second aspect of the application;

[0029] Figure 8 Shows Figure 7 A portion of the printer is in another operating state;

[0030] Fig. 9 shows a schematic side view of a printer including an exemplary apparatus according to the third aspect of the present application;

[0031] Fig.10 Shows Fig. 9 A portion of the printer is in another operating state;

[0032] Fig.11 is based on Figure 2 Schematic and exemplary representation of a printer device;

[0033] Fig.12 is a schematic diagram of an exemplary controller and connected entities;

[0034] Fig.13 is an exemplary schematic controller according to one aspect of the present application; and

[0035] Fig.14 and Fig.15 An arrangement of a media sensor according to one aspect of the present application is shown. DETAILED DESCRIPTION

[0036] The term "industrial printer," also known as "industrial-grade printer," as used in this article can refer to types of printers that are specifically designed for heavy-duty printing tasks in industrial environments. These types of printers are designed to handle high volumes of printing, are typically fast, highly accurate, and able to print on a variety of materials such as paper, cardboard, labels, plastics, and metals. Industrial printers as referred to in this article are typically used in industries such as manufacturing, logistics, packaging, and retail that require efficient, reliable printing solutions. They are often more rugged than standard office printers because they need to withstand harsher conditions and longer operating times.

[0037] Industrial label printers may use different printing technologies depending on the application. Some common types may include:

[0038] - Thermal Transfer Printers (TTP): These printers use heat to transfer the ink from the ribbon to the printing material, such as labels or tags. They are widely used in barcode printing and labeling applications.

[0039] - Direct Thermal Printers (DTP): These printers use thermal paper that turns black when exposed to heat, printing the desired pattern. They are often used to print receipts, shipping labels, or temporary labels.

[0040] -Inkjet Printers: Industrial inkjet printers use inkjet technology to eject tiny droplets of ink onto a printing surface. They can print high-resolution images and are suitable for printing on a variety of materials, including paper, plastic, and metal.

[0041] -Laser Printers: Industrial laser printers use laser technology to create the desired prints. They are typically used for high-speed and high-volume printing applications.

[0042] Industrial printers may also include additional features such as advanced connectivity options, rugged housings, automatic label applicators, inline verification, imaging solutions or integrated systems for data management and control. These features can improve their productivity, efficiency and integration with other industrial processes.

[0043] Thermal printers may also include thermal transfer printing (TTO) technology, where the printer also uses a thermal transfer printing method. The printer has a thermal print head, which contains an array of tiny heating elements. When the print head comes into contact with the (thermal transfer) ribbon and packaging material, it selectively heats the ribbon to transfer the ink to the substrate, creating the desired print effect. TTO printers are typically used for flexible packaging materials such as films, foils, papers, and labels. They can print on a variety of packaging surfaces, including continuous roll materials or preformed packaging such as bags and pouches.

[0044] As used herein, the terms "ribbon," "color ribbon," or "ink ribbon" generally refer to a consumable component used to transfer ink to a print medium, typically paper or labels.

[0045] The term "label" as used herein may include information carrier media that may be made from a variety of materials, depending on the specific requirements and application. Some common materials used for printer labels may include (but are not limited to): paper, synthetic materials, card stock, clear transparencies, thermal labels, and specialty materials.

[0046] The term "label backing" or "liner" as used herein may include different carriers, which may be made of different materials. A carrier may include a protective layer that covers the adhesive side of a label before it is applied to a surface. It is designed to be easily peeled off, allowing the label to be adhered in place.

[0047] The present invention relates to a design and arrangement for saving printheads and / or ink ribbons that can handle both near edge and flat head printheads. In the case of flat head printheads, the arrangement of the present application can allow one printer to print using both direct thermal labels and thermal transfer ribbons. This provides full flexibility to switch between the two technologies without wasting more ink ribbon than necessary when using thermal transfer technology.

[0048] As described below, this arrangement allows the printhead to be in at least three positions: a printing position, a ribbon and / or printhead and / or drive roller storage position, and a service position. It also provides suitable gearing for all three positions. In addition, no parts are exposed to wear and no surfaces rub against each other without bearings.

[0049] Figure 2 An exemplary printer 100 is schematically shown including an apparatus according to the present invention for positioning a print head 110. The printer 100 further includes an apparatus 120 for moving the print head 110, a label supply spool 130 of label material mounted to a supply spool support 131, a label take-up spool 140, an ink ribbon supply spool 150, an ink ribbon take-up spool 151, a plurality of (drive) rollers 161, 162 and 163, and a label peeling nozzle 170.

[0050] The print head 110 may be mounted on one or more print head supports 111. For example, in the case of two supports, the print head may be sandwiched between the two supports.

[0051] According to this example, the print head displacement device 120 includes a driving mechanism, such as a motor (not shown), a driving shaft 121 , a first arm 122 , a second arm 123 , and a second arm shaft 1231 .

[0052] The bracket 111 is generally rectangular in shape with a generally convex middle portion 113. One end of the bracket 111 is rotatably connected to the printer support wall or main frame by a bracket shaft 112, which is located opposite the printing element of the print head. The second arm 123 of the displacement device is rotatably connected to the generally convex portion 113 of the bracket by a second arm shaft 1231, which is located at one end of the second arm. At the other end, the second arm 123 is rotatably connected to one end of the first arm 122 by a shaft or pin. The other end of the first arm 122 is connected to a drive shaft 121. The drive shaft 121 is associated with a motor, for example, by a gear, a gearbox or a drive belt, such as a timing belt. This therefore allows the print head connected to the bracket 111 to be rotatably displaced around the axis of the shaft 112.

[0053] The actuator / motor and the motors for the rollers and spool supports may be controlled by a controller, as will be described in more detail below.

[0054] Figure 2The print head 110 is further shown in the printing position. When the print head is in the printing position and the correct (sufficient) pressure is applied to the front drive roller 162, the wrapper trajectory / speed (e.g., driven by the drive roller followed by the web) can be mainly controlled by the front drive roller 162. The rear drive roller 163 follows the front drive roller but in the opposite direction (as shown by the arrow). In one embodiment, during a complete printing cycle, the first label after a label change is printed with the print head in the printing position. During this printing cycle, the label rewinder can be mainly controlled by torque. This allows feeding a known portion of the base paper and measuring the label rewinder diameter. The printer controller can have information about the known portion of the base paper, which controls the rollers and the label web path. When the two parameters of label length and label rewinder diameter are known, the print head can be lifted during the printing cycle to save ribbon when printing is not required. This can also save print head wear and front drive roller wear. The speed ( / position) of the label rewinder is then mainly controlled to ensure that the label is fed correctly.

[0055] When the printer begins operation, for example, whether it is performing a media / gap sensor calibration or printing a label, a "print" torque is applied to the motor. The print torque can cause the print head to apply approximately 25-50N of pressure on the print media. The controller calculates the print torque and the calculated "print" torque for all relevant possible positions of the print position can be stored in the controller memory. The possible positions of the print position may vary due to label thickness, drive roller wear and printhead thickness variations. The "print" torque can be pre-calculated using a transmission device generated by the arm angle using the actual print head position of the print position, and can be defined as the number of motor pulses below the reference position. Therefore, the print head is now in the print position and is pushed by the "print" torque.

[0056] The rear drive roller 163 assists in the feeding of the paper track, against which the paper track pushes during the printing cycle.

[0057] Figure 3 Shows Figure 2 As previously mentioned, the print head lifting mechanism 120 is composed of a motor 124 and two arms 122 and 123 for positioning the print head support 111, thereby positioning the print head 110. The drive mechanism of the motor 124 and the arm includes a belt 125 and a pulley 126, which are shown in dotted lines because they can be arranged behind the support wall or the main frame 101. The motor can be a stepper motor or a brushless motor, which can arrange a drive wheel on the shaft and connect to the pulley 126 through the belt 125.

[0058] The first arm 122 is driven by a motor 124 and the second arm 123 is connected to the first arm and to a bracket 111 holding the print head. The rotational position of the motor can be measured, for example, by an encoder and the motor torque can be measured, for example, by measuring the drive motor current. At start-up, the print head positioning system can be calibrated using a sensor or, for example, by operating to an upper stop position. The sensor can, for example, be a print head positioning rotation sensor or a relative print head positioning sensor. The print head is then lifted and pushed down with a known force by measuring the torque and position. The print head lifting mechanism can also be designed to allow the high pressures required to bring the print head close to the label. Figure 3 In the figure, the motor rotates counterclockwise, driving the pulley 126 to rotate counterclockwise, and the first arm 122 is fixed on the driving shaft of the pulley 126. The first arm rotates with the pulley and rotates along the central axis of the shaft 121, pulling the second arm 123 upward (relative to the drawing). This movement pulls the bracket 111 in the middle part, and the bracket 111 rotates along the central axis of the shaft 112, thereby lifting the print head 110. The print head does not contact the ribbon or label, so it will not cause wear to the ribbon or the print head, thereby avoiding wear of the print head, the driving roller and the ribbon.

[0059] Of course, the belts and pulleys may be replaced by gears and a gearbox or any other suitable drive mechanism.

[0060] In some exemplary embodiments, when the printer is operating in direct thermal mode and reaches an area where there is no print job, the motor can switch to a "print head holding" torque until a print job is available again, at which point the motor switches back to a "print" torque. This may change the mechanical print head position very slightly due to reduced compression of the drive / print roller, but the motor controller does not need to actively assume the new position.

[0061] When access is required, such as for label replacement or cleaning operations, ie, a service position, the printhead can be moved further away from the label (or print media) and print / drive roller. Figure 4 Shown with Figure 3 The same part of the printer 100 in FIG.

[0062] exist Figure 4 In the process, the motor 124 further rotates counterclockwise, driving the pulley 126 to rotate counterclockwise, causing the first arm 122 to rotate, thereby pulling the second arm 123 further upward (relative to the drawing). The bracket 111 is further pulled in the middle part and rotated along the central axis of the shaft 112, so that the print head 110 is further lifted. This allows easy access to the interior of the printer, especially the space between the print head and the front roller 162, and allows easy replacement of labels, cleaning or replacement of the drive roller, or cleaning or replacement of the print head.

[0063] In one embodiment, the distance d1 of the ribbon (and / or print head) storage position, that is, the distance between the print head element and the ribbon / medium (label) can be less than 0.1mm-2mm, preferably less than 1mm above the printing position, which means that the movement from the printing position to the ribbon storage position is very fast.

[0064] In one embodiment, in the service position, the distance d2 (ie the distance between the print head element and the ribbon / media (label)) may be 2 cm - 10 cm, preferably 6 cm above the printing position.

[0065] During a printing operation, when a no-print area is indicated and the print head is allowed to be lifted, the controller shifts the print head to a ribbon saving position, which also saves wear on the print head and roller 162. Ribbon saving can also be defined as n pulses above the printing position, i.e. n pulses (control signals) to step or drive the motor. Each time the printing position is reached, the printing position can be redefined. When the ribbon saving position is reached, the motor position is maintained. As soon as a printing operation is required, the motor rotates in the opposite direction to move the print head to the printing position again by applying a "printing" torque. Due to the short distance between the ribbon saving position and the printing position, the need for label (printing medium) feed speed control can be eliminated.

[0066] The printer may need to calibrate the position of the print head. To do this, the print head is raised at a fixed slow speed until the motor stops. This can be defined by the controller as no input pulses from the pulse encoder on the motor for a set period of time. Motor torque can be limited by motor current limiting.

[0067] The stop position is stored in a memory that communicates with the controller as a "reference" position. In one embodiment, the stop position can be defined as a position where the motor cannot be driven further because the first arm 123 is prevented from moving further by the component 129 (e.g., Figure 4 ). The service position can be defined as m motor pulses (forwards or backwards depending on the configuration) from the "reference" position. In the case of moving the print head up and down, it is m pulses below the reference position. The motor then moves down to the service position with m pulses. When the service position is reached, this position is maintained until the user performs the necessary actions and activates the printer. The service position can be entered manually by the user (operator) or automatically if, for example, the printer detects that the printer needs to be serviced, the printer is out of labels or ribbon.

[0068] When the printer is set to active mode, the print head moves out of service mode at a fixed speed. As the print head approaches the drive / print roller, the transmission provided by the two arms will slow down and increase torque. When the motor is stopped (defined as no pulses from the motor pulse encoder), an idle torque can be applied to the motor. The print head is now in the printing position and is pushed toward the print media and roller by the "idle" torque. In some exemplary embodiments, the idle torque can be less than 50% to 90% of the printing torque, preferably 75%.

[0069] Figure 5 Depicts how some of the forces in the printer assembly counteract each other to improve stiffness and print quality. In the printing position, the angles of the two arms 122 and 123 are such that the corresponding transmission ratio between the motor 124 and the distance d is low, and Fdot is high. If the motor instead engages the printhead support shaft 1231, the transmission ratio should be significantly higher, and in one embodiment, the transmission ratio can be 17:1, which is 5.67 times the 3:1 of the present application, which means that a gearbox may be required.

[0070] The precise arm angle, and thus the precise transmission, can be continuously monitored. This can be accomplished by calculating angles, lookup tables, etc. Changes in label thickness, printhead thickness, and drive roller diameter may vary over time, which may result in changes in the arm angle, and thus in the transmission, such as through input of the motor shaft angle. The magnitude of the motor torque can then be adjusted to achieve a substantially constant and correct pressure (Fdot) on the drive roller 162.

[0071] Both the first arm 122 and the printhead support 111 may be connected by ball bearings in common mechanical parts inside and outside the printhead, which ensures precise tolerances and rigidity.

[0072] The device of the present invention also offsets the outer common bracket 102 ( Figure 6 ) and only Fphps-x and Fphbs-x of equal magnitude and opposite direction are left. This offsetting effect has a great impact on the inner and outer brackets 103 ( Figure 6 ) applies less pressure. This minimized torsional force between the inner and outer brackets ensures proper alignment of the printhead, even under the relatively high forces required for thermal printheads (e.g., flat-head types).

[0073] Figure 7 and Figure 8An alternative solution for the drive mechanism for moving the print head 110' is shown. In this case, the bracket is provided with an axis 112' in approximately the middle of the generally rectangular bracket 11T. The drive mechanism also includes a motor 124', which is connected to a pulley 126' connected to a first arm 122' via a drive belt 125'. The first arm 122' is rotatably connected to a second arm 123', which is connected to the end of the bracket 11T. The bracket 11T is pivotally arranged on the axis 112'. The second arm 123' is slightly bent at the end connected to the first arm. The motor 124' is displaced to the front of the printer, i.e. the label feed side of the printer.

[0074] Figure 7 The print head 110' is shown in the printing position when the second arm lifts the end of the support 111' and applies pressure to the front roller.

[0075] Figure 8 The print head is shown in the so-called service position. The motor 124' rotates clockwise, driving the pulley 126' to rotate, thereby rotating the first arm upward, pushing the second arm 123' downward, thereby pushing the end of the bracket 111' downward, and the bracket pivots about the axis of rotation of the shaft 112', lifting the print head 110' to the service position. All directions are relative to the plane of the drawing.

[0076] For example, the print head and ribbon storage position is achieved by rotating the motor slightly clockwise from the printing position.

[0077] Fig. 9 and 10 Yet another alternative solution for the drive mechanism for moving the print head 110" is shown. In this case, the bracket 111" is provided with a shaft 112". The bracket 111" comprises a middle portion protruding on the upper side, which is substantially sinusoidal in shape. The drive mechanism further comprises a motor 124", which is connected via a belt 125" to a pulley 126" connected to a first arm 122". The first arm 122" is rotatably connected to a substantially circular or wheel-shaped actuator 123", which is in contact with the protruding middle portion 113" of the bracket 111". The bracket 111" is rotatably arranged on the shaft 112". The end portion of the bracket 111" is provided with a spring 128 via an extension, which is connected to the bottom portion of the printer. The spring 128 is arranged to pull the end portion of the bracket downwards. Obviously, the operation and direction of movement of the spring can be changed.

[0078] Fig. 9The printhead 110" is shown in the printing position, where the actuator 123" applies pressure on the top of the raised portion and lifts the end portion of the bracket 111", biasing the spring 128 and applying pressure to the front roller (and ribbon / media). For example, the printhead and ribbon storage position can be achieved by rotating the motor slightly counterclockwise from the printing position.

[0079] Fig.10 The print head is shown in the service position. The motor 124" rotates counterclockwise, rotating the pulley 126', thereby rotating the first arm upward, causing the actuator 123" to roll over the protrusion, causing the spring to pull the end of the bracket 111" back downward, and the bracket pivots about the rotation axis of the shaft 112", raising the print head 110" to the service position.

[0080] In some exemplary embodiments, the drive to move the print head can be driven directly by a motor or through a flexible coupling with defined characteristics. In some exemplary embodiments, the user / operator can set the print head in the service position and keep the print head raised and use the printer as a label dispenser.

[0081] Fig.11 An example of how to set the parameters of a printhead controller is shown. A typical flat head type printhead may need to be pushed against the drive roller with a force of 40N (measured at the dot row (Fdot)). In addition, some major factors may change that the design needs to be robust enough to handle. These factors may include:

[0082] Variation in label thickness;

[0083] Changing print head thickness; and

[0084] ·The diameter of the drive roller changes due to wear.

[0085] The variation is also measured at the point row and the total tolerance (d mm) is added up.

[0086] The label thickness may vary less than 0.5 mm measured at the dot row, the printhead thickness will vary less than 0.5 mm, and the drive roller will vary less than 0.5 mm (equal to a drive roller diameter reduction of less than 1 mm). Therefore, the total tolerance required at d is 1.5 mm.

[0087] This example will manage the required 1.5mm tolerance with a good margin. The distance d can be allowed to vary up to 2.51mm while maintaining Fdot>40N. This can be achieved with a brushless DC (BLDC) motor capable of providing 0.21Nm torque and using a 3:1 reduction gear before driving ribbon arm 1. Ribbon arm 2 is connected to ribbon arm 1 and the printhead holder.

[0088] The figure also illustrates that the torque force (Fhx) is a maximum of 14.58 N. This is compared to the case where the printhead support is driven directly via the printhead support shaft. The torque force will be 30-50 N, preferably 40 N, which is 174.3% higher than 14.58 N.

[0089] Fig.12 1 is an exemplary controller 1300 that communicates with and / or controls various units of an exemplary printer (e.g., a printer previously described in the present application). Controller 1300 can communicate with various sensors of the printer, such as encoders for motors 124, 124', and 124". The motors can include motors for driving spools, printhead displacement motors, rollers, etc. The controller can also be part of a printer controller that controls the operation of the printhead and can also communicate with other devices.

[0090] In some exemplary embodiments, the arrangement of the present application content can be implemented in a label printer using linerless labels. In this case, a linerless label strip is used, which can consist of adhesive-coated labels without any backing material. After printing and (pre)cutting the labels, they are peeled off the roll and presented to the label applicator one by one.

[0091] Fig.13 1 is a schematic diagram of an exemplary controller 1300 described above, in which the methods and systems described herein may be implemented. The controller 1300 may include a bus 1310, a processor 1320, a memory 1330, a read-only memory (ROM) 1340, a storage device 1350, an input device 1360, an output device 1370, and a communication interface 1380. The bus 1310 allows communication between components of the controller 1300. The bus may be any of several types of bus structures, which may also be interconnected with a memory bus (with or without a memory controller), a peripheral bus, and / or a local bus using any of a variety of bus architectures. The bus 1310 allows communication between components of the controller 1300. The controller 1300 may also include one or more power supplies (not shown). Those skilled in the art will recognize that the controller 1300 may be configured in a variety of other ways and may include other or different elements.

[0092] Processor 1320 may include any type of processor or microprocessor that interprets and executes instructions. Processor 1320 may include, for example, a general purpose processor, a special purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), a circuit containing a processing component, a group of distributed processing components, a group of distributed computers configured for processing, or other programmable logic devices, discrete gate or transistor logic, discrete hardware components, or any combination of functions designed to perform the functions described herein. The processor may also include computer executable code that controls the operation of the programmable device. Processor 1320 may also include logic that can receive and compile instructions and interpret different signals and generate outputs to, for example, speakers, displays, etc.

[0093] Memory 1330 may include random access memory (RAM) or another dynamic storage device for storing information and instructions for execution by processor 1320. Memory 1330 may also be used to store temporary variables or other intermediate information during the execution of instructions by processor 1320. Memory 1330 may be one or more devices for storing data and / or computer code to complete or facilitate the methods described herein. Memory may include database components, object code components, script components, or other types of information structures for supporting various activities described herein. Any distributed or local memory device may be used with the systems and methods of this specification. Memory may be communicatively connected to a processor device (e.g., via a circuit or any other wired, wireless, or network connection) and may include computer code for executing one or more processes described herein. The memory may include nonvolatile memory 1340 (e.g., read-only memory (ROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), etc.) and volatile memory (e.g., random access memory (RAM)), or any other medium that can be used to carry or store desired program code in the form of machine-executable instructions or data structures and can be accessed by a computer or other machine with a processor. A basic input / output system (BIOS) may be stored in the nonvolatile memory 1340 and may include basic routines that help transfer information between elements within the controller.

[0094] ROM 1340 may include conventional ROM devices and / or other static storage devices for storing static information and instructions for processor 1320. Storage device 1350 may include a magnetic or optical disk and its corresponding drive and / or some other type of magnetic or optical recording medium for storing information and instructions and its corresponding drive. Storage device 1350 may also include a flash memory (e.g., an electrically erasable programmable read-only memory (EEPROM)) device for storing information and instructions.

[0095] The input device 1360 may include one or more conventional mechanisms for allowing a user to input information to the controller 1300, such as a keyboard, a keypad, a directional pad, a mouse, a pen, voice recognition, a touch screen, and / or a biometric recognition mechanism, etc. The output device 1370 may include one or more conventional mechanisms for outputting information to the user, including a display, a printer, one or more speakers, etc. The communication interface 1380 may include any transceiver-type mechanism that enables the controller 1300 to communicate with other devices and / or systems. For example, the communication interface 1380 may include a modem or an Ethernet interface to a LAN. Alternatively, or in addition, the communication interface 1380 may include other mechanisms for communicating over a network (e.g., a wireless network). For example, the communication interface may include a radio frequency (RF) transmitter and receiver and one or more antennas for sending and receiving RF data.

[0096] In accordance with the present application, the controller 1300 provides a platform through which various functions of the labeling machine, either independently or in combination with a printer, can be controlled. The controller 1300 can also display information related to the label application status of printer-related information.

[0097] According to an exemplary embodiment, the controller 1300 may perform various processes in response to the processor 1320 executing the instruction sequence contained in the memory 1330. Such instructions may be read into the memory 1330 from another computer-readable medium (e.g., storage device 1350) or from a separate device through the communication interface 1380. It should be understood that the computer-readable medium may include one or more storage devices or carrier waves. Executing the instruction sequence contained in the memory 1330 causes the processor 1320 to perform the described actions. In alternative embodiments, hard-wired circuits may be used instead of or in combination with software instructions to implement aspects consistent with the present application. Therefore, the present application is not limited to any specific combination of hardware circuits and software.

[0098] Gap sensors can also be installed in label dispensers for dispensing pre-printed labels. Both the printer and the dispenser need to detect the starting position of a new label so that the label can be delivered correctly. The label printer also needs to print in the correct position.

[0099] There are two main designs of label printer / dispensers: open and closed. The open design is the most common. The closed design is more robust and requires no adjustments, but it has some known disadvantages, which are addressed in this article.

[0100] The open design is the most common design for label printers and label dispensers / applicators. This design can be described as a large two-legged fork, where new media, labels and ribbons can be loaded from the side between the two fork legs when in use.

[0101] The open design makes it easy to load new media and eliminates the risk of errors such as labels not passing the sensor, but the stability / rigidity of the design becomes a challenge. This is especially true when using a thermal printhead that needs to be pressed hard against the label material.

[0102] One way to overcome this challenge is to add an openable connection between the printhead holder and the part that holds the drive / print roller, with the two pushing against each other. This mechanism adds stability, but it needs to be very durable and very precise so as not to affect the tight tolerances required of label printers.

[0103] Label / media sensors typically have a fixed gap and fork shape, the label must be guided between the two media sensor fork legs. This fits in well with the open design.

[0104] Standard forked label / media sensors read the label and the liner / backing paper to detect the gap between labels. This can be done through several different methods such as infrared, ultrasonic or by reading the change in capacitance created by the gap between labels.

[0105] If an ink ribbon is used in a label printer, the ink ribbon will not normally pass through the label / media / gap sensor.

[0106] This means that with an open design a wide range of different label / media / gap sensors can be used, giving the flexibility to handle different types of labels and ink ribbons (if used).

[0107] In summary, open designs are generally easy to use and flexible; however, adjustments may be required to handle mechanical tolerances in the design and changes over time.

[0108] The design can also be closed. When produced with precision tools (such as CNS machines) and combined with precision components (such as ball bearings), the complete solution becomes extremely precise and robust, requiring no adjustments from the outset and over time.

[0109] The main challenge with the enclosed design is the label / media / gap sensor. Due to the enclosed design, labels cannot be loaded from the side using the standard fork-type label / media / gap sensor.

[0110] The closed design can be compared to a gate or door that needs to open wide enough so that a hand can pass through it to load media. Using a normal form media sensor with a small gap would be a poor choice and complicate label changes.

[0111] There are at least two previously known methods for easily changing labels when using a closed design, but both suffer from the drawback of media flexibility.

[0112] One solution is to use a reflective label / media / gap sensor that looks at the backing / liner from below, such as using infrared, and detects the change in contrast when there is a gap between labels. This approach solves many problems, but reflective sensors cannot reliably detect label gaps when there is print underneath the labels or very strong contrast pre-printed on top of the labels.

[0113] Another approach, often used in label printers, is to read both the label and the backing / liner, but split the sensor into two parts. One part (transmitter or receiver) is placed under the backing / liner, and the other part (transmitter or receiver) is placed in the part that holds the print head, which is usually moved away from the label when a label needs to be changed.

[0114] This creates a natural opening for easy label changes. However, when used in conjunction with a ribbon, it introduces some serious limitations. When the two sensor parts are placed in this way, there is not only the label and liner / pad between the two sensor parts, but also the ribbon. Infrared light has difficulty penetrating the ribbon and will add significant noise to the ultrasonic signal, making it unreliable. The capacitive sensor will still be able to detect the label gap, but the gap will cause the distance between the sensor parts to change, which will interfere with the signal. It is possible to compensate for the mechanical movement by adding additional capacitive sensors, but this will create a very complex sensor.

[0115] The media / label / gap sensor according to the present application can be used in a closed design and it allows the label to be changed as easily as the reflective sensor option and the reflective sensor option described above. However, the device according to one aspect of the present application has the following two main features:

[0116] 1. It does not use a reflective reading method from underneath the paper / substrate. It reads both the label and the backing paper / substrate simultaneously.

[0117] 2. It can read labels and paper / substrates, but will not read ribbon, which makes it as flexible as a standard type media / label / gap sensor.

[0118] According to the present application, a media / label / gap sensor can be combined with a closed, adjustment-free design while maintaining ease of use and maintaining sensor performance and flexibility.

[0119] The teachings of the present application also allow the label printer to align the label to or near the center of the printhead, which is not possible with a standard fork type media sensor because the fork legs are typically too short.

[0120] Label applicator systems and print and apply labeling systems often need to accommodate uneven surfaces when applying labels. This is because the target product is not always perfectly flat and / or aligned.

[0121] Label applicator solutions are designed to accommodate uneven surfaces and work best if they can operate in a symmetrical manner, placing the label in the center of the label applicator.

[0122] This can be achieved by making a mechanical adjustment / configuration between the label printer / dispenser and the label application module to ensure that the label is always presented / fed to the applicator adjusted to the center line.

[0123] However, this can also be achieved by always adjusting the label roll to the centerline of the label printer / dispenser.

[0124] In addition, many product packaging / sealing machines output products in the center of the conveyor. Often, when using different sized labels on the same production line, the label should be applied to the target product aligned with the center of the conveyor.

[0125] To achieve labeling in the center of the product conveyor, it is best to make as few mechanical adjustments as possible.

[0126] This is achieved by mechanically fastening the three main modules in the system together by adjusting the label roll to the center of the label printer / label dispenser, resulting in a simple overall system with no further mechanical adjustments required. All three modules are:

[0127] 1. Label Printer / Dispenser

[0128] 2. Label applicator

[0129] 3. Conveyor belt / production line

[0130] The most common label printer and label dispenser design is to adjust the label to one side. Left or right, making it impossible to fix the three modules above to each other.

[0131] Therefore, when labels are adjusted to the left or right of the label printer / dispenser, the label applicator module must be moved left / right relative to the label printer / dispenser in order to feed the labels onto the center label applicator.

[0132] The label applicator module can be fixed in an inclined position in the print and apply system by adjusting the label to the center of the print head. Adjusting both the label applicator module and the label to the center of the print head allows symmetrical adaptation to uneven surfaces.

[0133] In an exemplary design according to the present application, Fig.14 and 15As shown, a portion 190 of the media detection sensor can be located in a fixed portion below the backing paper at a certain angle, while another portion 180 is located above and beside the label path 160, such as in the main frame 101, and the label replacement process will be very easy. The paper track can move up and down but cannot move sideways, which will ensure the accuracy of label edge detection. Therefore, the sensor portion forms the vertex of a roughly right triangle, and the electromagnetic signals sent and received by the sensor portion constitute the hypotenuse of the triangle side, so that the vertex angle is different from 90 degrees.

[0134] It should be noted that the word "comprising" does not exclude the existence of other elements or steps than those listed, and the word "a" or "an" before an element does not exclude the existence of multiple such elements. It should also be noted that any reference symbol does not limit the scope of the claims, the content of the present application can be at least partially implemented by hardware and software, and multiple "devices", "units" or "equipment" can be represented by the same hardware.

[0135] The terms used herein are only used to describe specific aspects and are not intended to limit the content of this application. As used herein, unless the context clearly indicates otherwise, the singular forms "one", "an" and "said" are also intended to include plural forms. As used herein, the term "and / or" includes any and all combinations of one or more related listed items. It should be further understood that the terms "include", "comprise", "contain" and / or "contain" used herein specify the presence of the features, whole pieces, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, whole pieces, steps, operations, elements, components and / or their groups.

[0136] It should be understood that although the terms "first", "second", etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another element. For example, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element without departing from the scope of the present application.

[0137] Relative terms such as "lower" or "upper" or "above" or "below" or "horizontally" or "vertically" may be used herein to describe the relationship between one element and another element as shown in the figures. It should be understood that these terms and the above terms are intended to cover different orientations of the device in addition to the orientation shown in the figures. It should be understood that when an element is referred to as being "connected" or "coupled" to another element, it can be directly connected or coupled to the other element, or there can be intervening elements. In contrast, when an element is referred to as being "directly connected" or "directly coupled" to another element, there are no intervening elements.

[0138] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as those commonly understood by ordinary technicians in the field to which this application belongs. It should also be understood that the terms used herein should be interpreted as having the same meaning as in the context of this specification and the relevant field, and should not be interpreted in an idealized or overly formal sense unless explicitly defined herein.

[0139] Software and web implementations of various embodiments of the disclosed methods can be implemented through standard programming techniques, wherein rule-based logic and other logic are employed to implement various database search steps or processes, association steps or processes, comparison steps or processes, and decision steps or processes. It should be noted that the terms "component" and "module" as used herein and in the following claims are intended to cover implementations using one or more lines of software code, and / or hardware implementations, and / or devices for receiving manual input.

[0140] It should be understood that the present application is not limited to the aspects described above and shown in the accompanying drawings; on the contrary, those skilled in the art will recognize that many changes and modifications may be made within the scope of the present application and the appended claims. In the drawings and description, aspects have been disclosed for illustrative purposes only and not for limiting purposes, and the scope of the inventive concept is set forth in the following claims.

Claims

1. A thermal printer for printing on a print medium, comprising: - a print head (110, 110', 110"), - a print head positioning device (120) for moving the print head, - a ribbon supply device, comprising a printing ribbon unwinder (150) and a ribbon rewinder (151), - at least one roller (162), and Wherein, in operation, the print head positioning device is configured to shift the print head to at least three positions: a first position where a first amount of pressure is applied to the print medium, a second position where a second amount of pressure is applied to the print medium, and a third position where the print head maintains a distance from the print medium and does not apply pressure to the print medium.

2. The thermal printer according to claim 1, wherein: The print head positioning device is configured to apply the same pressure on the print ribbon configured to extend substantially parallel to the print medium as applied to the print medium.

3. The thermal printer according to claim 1 or 2, wherein: The print head positioning device comprises a first arm (122, 122', 122"), one end of which is connected to an actuator (124, 124', 124") and an axis (112, 112', 112") that rotatably attaches the print head to a support structure (101), wherein the first arm is configured to shift the print head to the at least three positions.

4. The thermal printer of claim 3, wherein the first arm is connected to a second arm (122, 122', 122"), the second arm mechanically connecting the first arm to the actuator.

5. The thermal printer according to claim 4, wherein: The first arm is mechanically and rotatably connected to the print head support structure (111, 111') and thus to the print head between said at least three positions.

6. The thermal printer of claim 4, wherein the second arm (123") is configured to apply a force to the print head support structure (111").

7. The thermal printer of claim 6, further comprising a spring mechanism (128) mechanically attached to one end of the print head support structure and configured to apply a second force to the print head support structure and position the print head in the at least three positions.

8. The thermal printer according to claim 3 further includes a bearing for holding at least one roller, an axis and an axis for a print head support structure, wherein the bearing is attached to at least a first bracket (101) on a first side of the thermal printer and a second bracket (102) on a second side of the thermal printer, and the first bracket (101) and the second bracket (102) are mechanically connected.

9. A thermal printer according to any one of claims 3 to 8, further comprising a sensor configured to provide a position of an actuator connected to the first arm when activated.

10. The thermal printer of claim 9, wherein the sensor comprises one of a print head positioning rotation sensor or a relative print head positioning sensor.

11. The thermal printer according to any one of claims 3 to 10, comprising a memory configured to store a reference position and a fixed stop position of the movement of the first arm.

12. The thermal printer according to any one of the preceding claims, further comprising a print media sensor, the print media sensor comprising at least a first portion and a second portion: the first portion is configured as a transmitter for sending an electromagnetic signal and the second portion is configured as a receiver for receiving the electromagnetic signal, wherein The first portion and the second portion are arranged such that they form vertices of a substantially right triangle and the electromagnetic signal path is the hypotenuse of the sides of the triangle.

13. The thermal printer according to any one of claims 1 to 12, wherein: In the second position, the printhead is adjacent to the print medium and the print ribbon between the printhead but spaced apart from the print ribbon.

14. The thermal printer of claim 1 including a flexible coupling having defined characteristics for moving the print head.

15. The thermal printer according to any one of claims 1 to 14, wherein: The print head is configured to be disposed in a third position and to remain in the third position to allow the printer to operate as a label dispenser.

16. A method for controlling the position of a print head (110, 110', 110") in a thermal printer, the thermal printer comprising: a print head positioning device (120) for moving the print head, A printing ribbon supply device, comprising a ribbon unwinder (150) and a ribbon rewinder (151), at least one roller (162), and The method comprises: - Move the print head to at least three positions: - a first position, applying a first amount of pressure on the print medium between the print head and the roller during a printing operation; - a second position, when no printing operation is performed, applying a second amount of pressure on the print medium, - A third position, in which the print head is kept at a distance from the print medium and does not apply pressure to the print medium.

17. The method according to claim 16, further comprising: - receiving information indicating the position of the print head at said first location and exerting a predetermined force F on the print head dot ; - when the active printing task is finished in the first position, moving the print head to the second position; optionally - Move to the third position after receiving the command.

18. The method according to claim 16 or 17, wherein: The rewinder is torque controlled in the first position and speed controlled in the third position.

19. The method according to any one of claims 16 to 18, further comprising: - in a first position, the web path is controlled by a roller, wherein the print head applies a predetermined pressure to the roller; -Measure the length of the printed media and the diameter of the printed media rewind; - shifting the print head to a second position during the print cycle without actively printing based on the measured length and rewind diameter; and - Controlling the label rewind speed, wherein during the printing cycle the feeding of the print medium is assisted at least by a roller having the print medium pushed towards it.

20. A method according to any one of claims 16 to 19, wherein the print head positioning device (120) includes two arms for moving the print head, wherein the angles of the two arms (122, 123) are monitored substantially continuously to detect changes in print medium thickness, print head thickness and roller diameter, thereby adjusting the amount of torque from the actuator to achieve a substantially constant first pressure.

21. A method according to any one of claims 16 to 20, wherein the first position is a printing position, the second position is a non-printing position, and the third position allows access to thermal printer components.

22. A method according to any one of claims 16 to 21, wherein in the second position the print head is adjacent to but spaced apart from the print medium and the print ribbon between the print head.

Images