Printer and its control method

Abstract

The present invention provides a printer and its control method that can accurately determine the starting position for printing on a printing medium while suppressing cost increases. [Solution] The printer (100) according to this disclosure includes a transport unit (10) that transports a plurality of printing media (B) connected with gaps (G) in the transport direction (D), a detection unit (8) that outputs a detection signal capable of detecting the positions of the printing media (B) and the gaps (G), a printing unit (60) that prints print information on the printing media (B) from the print start position, and a control unit (110) for these. The control unit (110) then determines the print start position based on the detection signal.

Description

Technical Field

[0001] The present disclosure relates to a printer and a control method thereof.

Background Art

[0002] Conventionally, as a means for detecting the reference position of a print medium in a printer, a method is known in which marks are provided on the print medium, or gaps are formed between the print media, and the print start position (print position) is determined by detecting these marks or gaps. For example, Patent Document 1 describes a control method in which a reflective optical sensor is used in a label printer to detect a maximum value or a minimum value of an analog waveform acquired during label conveyance, so as to identify the central portion of a position detection mark.

Prior Art Document

Patent Document

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, when the spot diameter of the sensor is excessively large relative to the mark or gap that is the detection target, there is a problem that a large error occurs between the detected position and the actual position. On the other hand, if a high-precision sensor with a small spot diameter is used, the detection accuracy of the boundary (edge) of the mark or gap can be ensured, but as a result, the problem arises that the entire apparatus becomes high in cost.

[0005] The present disclosure has been made in view of the above problems, and an object of the present disclosure is to provide a printer and a control method thereof, which are capable of accurately determining the print start position on a print medium and can suppress an increase in cost.

Means for Solving the Problems

[0006] [1] To achieve the above objective, the printer according to this disclosure comprises a transport unit that transports a plurality of printing media connected with gaps between them in a predetermined transport direction, a detection unit that outputs a detection signal capable of detecting the position of the printing media and the gaps, a printing unit that prints print information on the printing media from a print start position, and a control unit that controls the transport unit, the detection unit, and the printing unit. The control unit determines the print start position based on the detection signal. In this disclosure, "printing" is a concept that includes "printing".

[0007] In a printer with such a configuration, a transport unit transports the printing medium in a predetermined direction while a printing unit prints the print information. Multiple printing media are connected via connecting members, and gaps are provided between the printing media. A detection unit detects the position of the printing media and the gaps during transport, and a control unit determines the printing start position based on the detection signals. Thus, in this disclosure, instead of directly determining the printing start position from the detection positions of marks on the printing media or gaps as in the conventional method, the printing start position is determined based on the detection results of the printing media. As a result, errors included in the detection results of the printing media do not propagate, or errors can be canceled out, thereby improving the accuracy of the printing start position.

[0008] [2] In this case, the control unit may identify a reference position based on the position of the printing medium and the gap, obtain the leading edge position in the transport direction of the printing medium based on that reference position, and determine the printing start position based on that leading edge position. In this way, first, the reference position is identified based on the position of the printing medium and the gap, and then the printing start position on the printing medium is determined using the leading edge position information obtained from that reference position. Thus, the printing start position can be determined accurately and easily.

[0009] [3] Specifically, the control unit may identify the center of the printing medium in the width direction as the reference position and calculate the leading edge position based on the reference position and the width dimension of the printing medium. In this case, since the reference position is the center of the printing medium in the width direction, the leading edge position in the width direction of the printing medium corresponds to a position located half the width (width distance) of the printing medium downstream (towards the leading edge in the transport direction) from that reference position. As a result, the printing area of ​​the printing medium can be determined more accurately and easily, and the accuracy of the printing start position can be further improved.

[0010] [4] More specifically, the control unit may acquire singularities indicating the position of the gap from the rising and falling edges of the waveform of the detection signal, and identify the widthwise center as the reference position from these singularities. In this way, by using information from at least two singularities related to the gap to calculate the widthwise center of the printing medium, the errors contained in each are canceled out, the widthwise center of the printing medium can be identified more accurately, and the accuracy of the printing start position can be further improved.

[0011] [5] In this case, the control unit may detect singularities based on the slope or curvature before and after the peak in the waveform of the detection signal. In this case, for example, two singularities corresponding to signal values ​​with equivalent slope or curvature before and after the peak may be located equidistant from the widthwise center of the printing medium toward the upstream and downstream sides, and their midpoint may correspond to the widthwise center of the printing medium. Therefore, by calculating these midpoints, the reference position can be determined more accurately and simply.

[0012] [6] The control unit may also detect the maximum gradient point or inflection point before and after the peak in the waveform of the detection signal as singular points. These maximum gradient points or inflection points are located equidistant from the center of the printing medium in the width direction toward the upstream and downstream sides, and their midpoints may correspond to the center of the printing medium in the width direction. Therefore, by calculating these midpoints, the reference position can be determined more accurately and simply.

[0013] [7] Furthermore, the detection unit may have a through-type or reflective (diffuse reflection type or retroreflection type) optical sensor, a capacitive sensor, or an ultrasonic sensor. In this disclosure, these sensors can be appropriately selected and used, and even if the spot diameter of the sensor is excessively large relative to the gap in the printing medium, the printing start position can be determined with high precision by the control described above. This reduces the overall cost of the device without requiring high precision in the detection unit.

[0014] [8] The present disclosure is particularly useful for configurations in which printing media are connected via connecting members, and the connecting members are formed to be expandable and contractible in a predetermined direction. Examples of such connecting members include those made of elastic material or those having a bellows structure. When the connecting members of the printing media are expandable and contractible in a predetermined direction, the gap between the printing media may not be constant, making it easy for the printing position to shift. In contrast, the printer of the present disclosure can accurately determine the printing start position based on the actual detection results of the printing media, and is therefore particularly effective for printing media that are prone to such printing position shifts.

[0015] [9] The printer control method according to the present disclosure is a printer control method comprising a transport unit, a detection unit, a printing unit, and a control unit, wherein the transport unit transports a plurality of printing media connected with gaps between them in a predetermined transport direction, the detection unit outputs a detection signal capable of detecting the positions of the printing media and the gaps, the printing unit prints print information on the printing media from a print start position, and the control unit identifies a reference position (reference position) for determining the print start position of the printing media based on the detection signal, obtains the leading edge position of the printing media in the transport direction based on the reference position, and determines the print start position based on the leading edge position. [Brief explanation of the drawing]

[0016] [Figure 1] This is a perspective view showing an example of the external configuration of the printer 100 according to this embodiment, and shows the printer as viewed from slightly to the left when facing its front. [Figure 2]FIG. 1 is a perspective view showing an example of the external appearance configuration of a printer 100 according to the present embodiment, and shows a state in which the printer is viewed from a slightly left side toward the back surface thereof. [Figure 3] FIG. 2 is a perspective view showing a state in which the lid portion of the printer 100 is opened and viewed from a slightly diagonally front upper side, and shows a state in which a consumable M1 is set. [Figure 4] FIG. 3 is a plan view schematically showing the configuration and positional relationship of part of members incorporated in the printer 100. [Figure 5] FIG. 4 is a block diagram showing an example of the hardware configuration and functional configuration of the printer 100. [Figure 6] (A) and (B) are a plan view (top view) and a front view, respectively, showing a part of the consumable M1. [Figure 7] (A) to (C) are a plan view (top view), a front view, and a side view, respectively, showing one structural unit of the consumable M1. [Figure 8] FIG. 7 is a side view schematically showing a state in which a print medium B in one structural unit of the consumable M1 being conveyed is detected by a sensor unit 8. [Figure 9] FIG. 9 is a flowchart showing an example of an operation procedure for determining a print start position on an unprinted (pre-printing) print medium B located on the upstream side of a print medium B after printing or during printing. [Figure 10] (A) is a top view schematically showing a part of the consumable M1 being conveyed, and (B) is a graph showing an example of actually measured waveforms when the print medium B and a gap G are detected for the consumable M1 in the system shown in FIG. 8. [Description of Embodiments]

[0017] Hereinafter, the present embodiment will be described with reference to the accompanying drawings. To facilitate understanding of the description, the same components in each drawing are denoted by the same reference numerals as much as possible, and duplicate descriptions are omitted. However, the embodiments described below are merely examples, and are not intended to exclude various modifications and applications of techniques not explicitly described below. That is, an example of the present disclosure can be implemented in various modified forms without departing from the gist thereof. In addition, the drawings are schematic, and do not necessarily match actual dimensions, ratios, and the like. Furthermore, parts with different dimensional relationships and ratios between the drawings may be included. It goes without saying that the embodiments described below are partial embodiments of the present disclosure, and are not all embodiments. Furthermore, all other embodiments obtained by a person skilled in the art based on the embodiments of the present disclosure without creative efforts shall fall within the protection scope of the present disclosure.

[0018] <Example of external configuration of printer 100> Figure 1 and Figure 2 are perspective views showing an example of the external configuration of the printer 100 according to the present embodiment. Figure 1 shows a state where the printer 100 is viewed from a slightly left side toward its front face, and Figure 2 shows a state where the printer 100 is viewed from a slightly left side toward its back face. As shown in these figures, the printer 100 includes a main body portion 1, and a lid portion 2 attached to the upper part thereof so as to be openable and closable. In addition, the main body portion 1 and the lid portion 2 are both housings having a substantially rectangular parallelepiped shape, for example, and the boundary between the two is formed on their front faces 1F, 2F and back faces 1B, 2B. The main body portion 1 and the lid portion 2 are connected at the boundary portion of their right side faces 1SR, 2SR, and the left side face 2SL of the lid portion 2 pivots around the boundary portion as an axis, so that the lid portion 2 can be opened and closed.

[0019] Furthermore, the front 1F of the main unit 1 is provided with a display / input / output unit 3 for performing various input operations and output displays to the printer 100, and an operation button 4 for fully cutting consumables. On the other hand, the rear 1B of the main unit 1 is provided with a connector unit 5 including a power switch and ports for connecting power cables and other communication cables. In addition, the display / input / output unit 3 has a screen such as a liquid crystal display or an organic EL display, and displays multiple operation buttons such as character buttons, number buttons, and a print start button, a settings screen, notification output to the user, and other necessary information based on commands from the control unit 110, which will be described later. Thus, the display of the display / input / output unit 3 also functions as a touch panel or touchscreen, and receives key inputs pressed by the user (for example, characters, numbers, symbols, designs, etc. to be printed on the printing medium B that constitutes consumable M1, or requests to select the type of consumable M1 or printing medium B), generates corresponding operation signals, and outputs them to the control unit 110, which will be described later.

[0020] Furthermore, the right side 1SR and left side 1SL of the main body 1 are provided with an insertion port SI and an outlet port SO for the consumables M1, which will be described later. On the other hand, the left side 2SL of the lid 2 is provided with an operating part 6 for opening and closing the lid 2.

[0021] <Example of internal configuration of printer 100> Next, Figure 3 is a perspective view showing the printer 100 with the lid 2 open, viewed from a slightly oblique frontal angle above, and shows the consumable M1 (a connected unit of printing media B) with multiple printing media B linked together set in place. Figure 4 is a schematic plan view showing the configuration and positional relationships of some of the components built into the printer 100.

[0022] As described above, the lid 2 is opened and closed by operating the operating unit 6 (for example, by pulling up a biased handle or button). Specifically, the lid 2 is closed when the locking claw E2 of the lid 2 engages with the locking receiver E1 of the main body 1 shown in Figure 3, and the lid 2 can be opened when this engagement is released by operating the operating unit 6. Also, as shown in the same figure, the printer 100 mainly contains a platen unit 10 (corresponding to an example of a "transport unit" in this disclosure), a positioning guide 20, an encoder unit 30, and a cutting unit 40, which are provided on the main body 1 side, and an ink ribbon unit 50 and a printer head 60 (corresponding to an example of a "printing unit" in this disclosure), which are provided on the lid 2 side. Furthermore, as shown in Figure 4, a sensor unit 8 (corresponding to an example of a "detection unit" in this disclosure) is positioned upstream of the platen unit 10 and the printer head 60 to detect the printing medium B and gap G (both described later) that constitute the consumable M1 and output the detection signal to the control unit 110, which will be described later.

[0023] The platen unit 10 includes, for example, a shaft 11 that is generally cylindrical in shape, and a cylindrical roller 12 fitted onto the shaft 11 so as to cover a part of the outer circumferential surface of the central part of the shaft 11. As will be described later, the consumable M1 conveyed by the platen unit 10 has a special shape with legs 71 protruding from the lower surface of the main body B, and the surface of the cylindrical roller 12 is not flat, but is shaped so that the legs 71 of the consumable M1 that reach the cylindrical roller 12 fit into it. The platen unit 10 is a component used when printing the consumable M1 and is replaceably attached to the main body 1 of the printer 100. More specifically, the platen unit 10 is rotatably and detachably supported on a bearing J provided on the downstream side in the forward conveying direction D of the consumable M1 (direction from the right side 1SR to the left side 1SL of the main body 1). Furthermore, in this state, the platen unit 10 is driven to rotate (forward or reverse) via the platen gear PG by a transport motor 13 (e.g., a stepping motor) driven based on a drive signal from the control unit 110, which will be described later. As a result, during normal transport, the consumables M1 are transported along the forward transport direction D, and, if necessary, during reverse transport, the consumables M1 are transported along the reverse transport direction (from the left side 1SL of the main body 1 to the right side 1SR).

[0024] The positioning guide 20 is provided along the transport direction of the consumable M1 and has two pairs of guides 21 and 22 for positioning the consumable M1 from both sides and guiding it to the printing position on the platen unit 10. These guides 21 and 22 are arranged on the upstream and downstream sides, respectively, in the forward transport direction D of the consumable M1. An attachment 7 for guiding the consumable M1 to the printing position on the platen unit 10 is detachably mounted between the two pairs of guides 21 and 22.

[0025] The encoder unit 30 is a component that enables printing on the same transport path even if the type of consumable M1 or printing medium B is different. For example, in the case of a consumable that has a different shape from consumable M1 and does not use the attachment 7, it has a feed amount detection roller (not shown) for detecting the feed amount (travel amount). In this embodiment, where printing is performed on the printing medium B that constitutes consumable M1, the attachment 7 is used and the feed amount detection roller is not used, so the encoder unit 30 is housed in the lower part of the main body 1 so as to be retracted from the transport path of consumable M1 (Figure 3 shows this state).

[0026] The cutting unit 40 is located downstream of the platen unit 10 and the printer head 60 in the forward transport direction D of the consumables M1, and has a cutter (not shown) for fully cutting the consumables into individual printing media B. The cutting unit 40 cuts the consumables M1 at predetermined positions using a cutting motor (not shown) driven based on a drive signal from the control unit 110, which will be described later.

[0027] The ink ribbon unit 50 includes an ink ribbon R and a bobbin 51 and cassette 52 that are detachably attached to both sides of the printer head 60 and house the ink ribbon R in a wound state. In this ink ribbon unit 50, for example, an appropriate rotary motor (not shown) that rotates the cassette 52 is configured to discharge the ink ribbon R from the bobbin 51 and collect it in the cassette 52 during the sequential transport of consumables M1.

[0028] The printer head 60 is positioned opposite the platen unit 10 and prints predetermined characters and numbers on the printing surface of the printing medium B constituting the consumable M1 by applying recording energy supplied from a head drive circuit (not shown) to the ink ribbon R. The printer head 60 moves closer to or away from the platen unit 10 by an appropriate head movement mechanism (not shown). Furthermore, during transport and printing of the consumable M1 in the forward transport direction D, the printer head 60 is pressed against the platen unit 10 with a predetermined pressure by a head pressing mechanism (not shown) and is configured to come into contact with it via the ink ribbon R.

[0029] <Example of Printer 100 Block Configuration> Figure 5 is a block diagram showing an example of the hardware and functional configuration of printer 100. As shown in the figure, printer 100 is equipped with a control unit 110 for controlling the operation of the entire device. The control unit 110 (processor) includes, for example, one or more CPUs, MPUs, GPUs, etc., and executes processes, functions, or methods realized by code or instructions contained in information processing programs stored in the memory 120 or storage 130 described later. This control unit 110 controls each part of printer 100 to realize the printing process on printing medium B, including the correction of misalignment of the transport of consumables M1.

[0030] Furthermore, the control unit 110 is connected to the display / input / output unit 3, sensor unit 8, platen unit 10, encoder unit 30, cut unit 40, ink ribbon unit 50, printer head 60, memory 120, storage 130, and interface 140 via an appropriate communication bus. Examples of communication buses include parallel buses, serial buses, memory buses, input / output buses, high-performance buses that integrate these, or buses based on communication standards similar to or conforming to these.

[0031] Furthermore, among these components, the memory 120 (corresponding to an example of a "storage unit" in this disclosure) is configured to include semiconductor memory such as DRAM, SRAM, DDR, ROM, flash memory, NVMe, MRAM, FRAM (registered trademark), and temporarily stores various data such as information processing and printing programs loaded from the storage 130, shape information including the widthwise dimensions of consumables M1 and printing medium B (such as the short side length Wa described later), printing information, detection information of the positions of printing medium B and gap G, position information calculated therefrom, theoretical transport amount and actual transport amount, correction amount calculated therefrom, and other calculation results, and provides a work area to the control unit 110.

[0032] The storage 130 stores the above-mentioned information processing program and various data. Examples of the storage 130 include one or more magnetic disk storage devices, optical disk storage devices, flash memory devices, and other non-volatile solid-state storage devices.

[0033] Interface 140 mediates various operations on the printer 100 and data communication with other parts, and may also include, as necessary, information output devices such as displays, speakers, and projectors other than the display / input / output unit 3, information input devices such as keyboards, mice, microphones, cameras, sensors, barcode readers, and scanners, and devices that serve as both input and output devices.

[0034] <Overview of the configuration of consumables M1> Figures 6(A) and (B) are a plan view (top view) and a front view, respectively, showing a part of the consumable M1, and Figures 7(A) to (C) are a plan view (top view), a front view, and a side view, respectively, showing one component unit of the consumable M1. As shown in these figures, the consumable M1 is a long body in which multiple rectangular plate-shaped printing media B (B1, B2, B3, ...) made of resin, for example, are connected with gaps G (G12, G23, ...) between them. The printing media B also has a short side Sa and a long side Sb, and the top surface is the printing surface. Furthermore, multiple legs 71 extending in the direction of the short side Sa are provided on the lower surface of the printing media B, projecting diagonally outward, and the lower end 71t of each leg 71 is bent so as to be parallel to the plane of the printing media B.

[0035] Furthermore, multiple printing media B are connected via connecting members 72 attached to the side wall Ss on the long side Sb. Each connecting member 72 has a simple bellows structure with one fold and is formed to expand and contract freely in the forward transport direction D of the consumable M1 (the direction in which the printing media B are connected). This connecting structure via connecting members 72 is configured so that the width of the gap G between each printing media B changes as needed during the transport of the consumable M1. That is, in the state shown in Figures 6(A) and (B), for example, the width W23 of the gap G23 between printing media B2 and B3 may be larger than the width W12 of the gap G12 between printing media B1 and B2. When printing of the consumable M1 having such a configuration is completed, printed printing media B are obtained. The lower ends of the legs 71 of the printing media B are fixed to a predetermined position on a terminal block by fitting them, for example, into each pole (hole) that constitutes a terminal block to which multiple wires are connected.

[0036] <Example configuration of sensor unit 8> Figure 8 is a schematic side view showing the state in which the sensor unit 8 detects the printing medium B in one component unit of the consumable M1 during transport. As shown in the figure, the sensor unit 8 is, for example, a retroreflective optical sensor and has a sensor section 81 and a reflector 82 that are arranged opposite each other so as to sandwich one end (shown as enclosed by a dashed circle in Figure 8) in the direction of the long side Sb of the printing medium B that constitutes the consumable M1. The sensor section 81 consists of a light-emitting section 81H including a light-emitting element (LED, LD, etc.) and a light-receiving section 81J including a light-receiving element (PD, CCD / CMOS sensor, etc.), as well as a lens, collimator, optical filter, drive circuit, and signal processing circuit. The reflector 82 has a reflective mirror, lens, etc., for defining an optical path to return the light P emitted from the light-emitting section 81H to the light-receiving section 81J.

[0037] <Example of operation with printer 100> Figure 9 is a flowchart showing an example of an operation procedure for determining the printing start position on an unprinted (pre-printing) printing medium B located upstream of a printing medium B that has been printed or is currently being printed. After starting the printing process, in step S10, the control unit 110 drives the transport motor 13 of the platen unit 10 with one pulse to transport the consumable M1 one (print) line (one step). On the printing medium B that is being printed, printing is continuously performed on the printing surface by the printer head 60 in one line increment with each such line transport. In this case, in ideal transport without transport unevenness, each printing medium B theoretically moves forward by one line width with one pulse drive of the transport motor 13.

[0038] Here, Figure 10(A) is a schematic top view showing a portion of the consumables M1 being transported, and Figure 10(B) is a graph showing an example of the measured waveform of the detection signal (a waveform showing the estimated position of the printing medium B and the gap G) when the printing medium B and the gap G are detected for the target consumables M1 in the system shown in Figure 8 (a dotted line curve L1). In Figure 10(B), the X axis indicates the position in the forward transport direction D. The Y axis shows the value obtained by A / D conversion of the analog output voltage from the sensor unit 8, which corresponds to the amount of light P emitted from the light-emitting part 81H of the sensor part 81 and returned to the light-receiving part 81J (i.e., the amount transmitted).

[0039] The control unit 110 can determine the printing start position for each printing medium B based on the following algorithm. Specifically, the control unit 110 first analyzes the curve L1, which is a waveform generated from the detection signal, to identify the reference position of the consumable M1 on each printing medium B. Furthermore, it calculates the leading edge position (X coordinate = X0) of the consumable M1 based on that reference position, and by applying the printing format to the calculated leading edge position, it determines the printing start position according to that leading edge position and printing information. Specifically, the widthwise center C (X coordinate = Xc) of the printing medium B can be identified as this reference position, and the leading edge position can be calculated based on that reference position and the widthwise dimension (short side length Wa, etc.) along the forward transport direction D of the printing medium B. That is, if the reference position is the widthwise center C of the printing medium B, it can be seen that the position located half the widthwise distance Wa of the printing medium B (Wa / 2) downstream corresponds to the leading edge position in the widthwise direction of the printing medium B.

[0040] At that time, the control unit 110 acquires positional information upstream and downstream of the widthwise center C of the target printing medium B based on the waveform curve L1 of the detection signal, and identifies the widthwise center C as the reference position. That is, from the plot of curve L1, it can be seen that when the printing medium B enters the detection range of the sensor unit 8 as the consumable M1 is transported, the amount of returned light decreases, and a convex upward peak (a negative peak in the Y-axis direction) is shown at the widthwise center C (X coordinate = Xc) along the short side Sa of the printing medium B. Also, when the gap G between the printing mediums B passes through the field of view of the sensor unit 8, the amount of returned light increases, and a convex downward peak (a positive peak in the Y-axis direction) is shown at the center of the gap G. At this time, since the light P has a finite spot diameter, although the slopes of the rising and falling parts of curve L1 are steep, they do not change vertically, but rather have a shape with a certain degree of inclination.

[0041] Therefore, in step S20 of Figure 9, the control unit 110 determines whether or not a singularity SP2 has been detected downstream of the center C in the width direction of the printing medium B (towards the leading edge in the forward transport direction D) based on the waveform of the detection signal, which is curve L1. If no singularity SP2 is detected (No in step S20), the control unit 110 repeats the process of step S10 (1 line transport). The detection of the singularity SP2 can be performed, for example, by the following method. That is, the control unit 110 detects the position coordinates of the point of maximum gradient or inflection point (the point where the unevenness reverses) before the peak of curve L1, based on the gradient or curvature of the rising portion of curve L1. In the example of curve L1, the control unit 110 analyzes the numerical changes in the rising portion before the peak and calculates the gradient and curvature, or their rate of change (derivative value), for each predetermined section. Then, the point of maximum gradient or inflection on the downstream side (long side Sb2 side) is detected as a singular point SP2 (X coordinate = X2: corresponding to an example of "downstream position information" in this disclosure).

[0042] When a singular point SP2 on the downstream (leading edge) side of the printing medium B is detected (Yes in step S20), the control unit 110 records the position information (X coordinate = X2) of the singular point SP2 in the memory 120 in step S30. Next, in step S40, the control unit 110 drives the transport motor 13 of the platen unit 10 with one pulse, similar to step S10, and transports one line.

[0043] In step S50, the control unit 110 determines whether a singularity SP1 has been detected upstream of the center C in the width direction of the printing medium B (towards the rear end in the forward transport direction D), based on the waveform of the detection signal, curve L1. If no singularity SP1 is detected (No in step S50), the control unit 110 repeats the process in step S40 (1 line transport). The detection of the singularity SP1 can be performed, for example, by the following method. That is, the control unit 110 detects the position coordinates of the point of maximum gradient or inflection point (the point where the unevenness reverses) after the peak of the curve L1, based on the gradient or curvature of the falling portion of the curve L1. In the example of curve L1, the control unit 110 analyzes the numerical changes in the falling portion after the peak and calculates the gradient and curvature, or their rate of change (derivative value), for each predetermined section. Then, the point of maximum gradient or inflection on the upstream side (long side Sb1 side) is detected as a singular point SP1 (X coordinate = X1: corresponding to an example of "upstream position information" in this disclosure).

[0044] When a singularity SP1 on the upstream (rear end) side of the printing medium B is detected (Yes in step S50), the control unit 110 records the position information (X coordinate = X1) of the singularity SP1 in the memory 120 in step S60. Next, in step S70, the control unit 110 calculates the position of the widthwise center C of the printing medium B (X coordinate = Xc) based on the positions of the singularities SP1 and SP2 (X coordinates = X1, X2) from the relationship expressed by the following equation (1). Xc = (X1 + X2) / 2 …(1)

[0045] As described above, the leading edge position in the width direction of the printing medium B is located downstream (towards the leading edge) by half the short side length Wa (Wa / 2) from the width direction center C. Therefore, in step S80, the control unit 110 calculates the X coordinate X0 of the leading edge position from the relationship expressed by equation (2) or equation (2)' below, and determines the printing start position on the printing medium B from the leading edge position and the printing information. X0 = Xc + Wa / 2 …(2) X0=(X1+X2+Wa) / 2 …(2)'

[0046] With the printer 100 and its control method configured as described above, a sensor unit 8 positioned upstream of the printer head 60 detects the printing medium B with high accuracy while the platen unit 10 is transporting the consumable M1. At this time, the waveform of the detection signal acquired by the sensor unit 8 has a shape that shows characteristic peaks in the region of the printing medium B and the region of the gap G, as shown in curve L1. Based on this waveform information, the control unit 110 accurately identifies the reference position of each printing medium B of the consumable M1 and further calculates the X coordinate X0 of the leading edge position of the printing medium B. Based on this, the print layout is applied and the print start position according to the print information of each printing medium B is determined. In contrast, in the conventional technology, the print start position was determined based on the detection position of marks or gaps on the printing medium, but in the printer 100 of this disclosure, the print start position is determined starting from the reference position identified based on the detection result of the printing medium B, so that the propagation of errors can be suppressed or canceled out. As a result, the accuracy of the print start position is improved and high-quality printing can be achieved.

[0047] Furthermore, the control unit 110 identifies the widthwise center C of the printing medium B as a reference position and calculates the leading edge position of the printing medium B with high precision based on this reference position and the shape information (short side length Wa) of the printing medium B. Specifically, as shown in equation (1) above, the leading edge position of the printing medium B is determined to be a position offset downstream from the widthwise center C by half the short side length Wa (Wa / 2). This makes it possible to accurately and easily grasp the printing area on the printing medium B, and further improves the accuracy of the printing start position.

[0048] Furthermore, the control unit 110 acquires positional information (X coordinates X1, X2) of singular points SP1 and SP2 upstream and downstream of the widthwise center C of the printing medium B, based on the waveform (curve L1) of the detection signal. By using this positional information to identify the widthwise center C as the reference position, errors contained in each can be canceled out, making it possible to more accurately identify the widthwise center C of the printing medium B, and as a result, the accuracy of the printing start position can be further improved.

[0049] In this case, the control unit 110 detects singular points SP1 and SP2 based on the slope or curvature of the rising portion before the peak and the falling portion after the peak in the waveform (curve L1) of the detection signal, more specifically, the point of maximum slope or inflection point before and after the peak. In this case, these singular points SP1 and SP2 are located on the upstream and downstream sides, equidistant from the widthwise center C of the printing medium B, and their midpoint corresponds to the widthwise center C of the printing medium B. Therefore, as shown in equation (1) above, the reference position can be determined more accurately and simply by calculating their midpoint.

[0050] Furthermore, the sensor unit 8 employs a retroreflective optical sensor comprising a sensor section 81 including a light-emitting section 81H and a light-receiving section 81J, and a reflector 82 with a defined retroreflective path. This makes it possible to determine the printing start position with high precision through the control described above, even if the spot diameter of the light P emitted from the light-emitting section 81H is excessively large relative to the gap G in the printing medium B. As a result, it is possible to reduce the overall cost of the device without requiring high-precision sensors.

[0051] In addition, in the consumable M1, the connecting member 72 that connects the printing media B is formed to be expandable and contractible along the forward transport direction D, so the gaps G12 and G23 between the printing media B may not be constant. In such situations, the conventional technology tended to cause misalignment of the printing position, but the printer 100 according to this disclosure determines the printing start position based on the actual detection result of the printing media B, thereby improving the accuracy of the printing position. Therefore, this disclosure is particularly effective for printing media that are prone to misalignment of the printing position, such as the consumable M1, and enables highly reliable printing.

[0052] The embodiments described above with reference to specific examples are for the purpose of facilitating understanding of this disclosure and are not intended to limit its interpretation. In other words, this disclosure is not limited to these specific examples, and designs modified by those skilled in the art are also included within the technical scope of this disclosure, as long as they retain the features of this disclosure. Furthermore, the elements, arrangements, materials, conditions, shapes, dimensions, scales, etc., of each of the aforementioned specific examples are not limited to those exemplified unless otherwise specified, and can be modified as appropriate. Moreover, the elements of each of the aforementioned specific examples can be combined in different ways as appropriate, as long as no technical inconsistencies arise.

[0053] In other words, for example, the printing medium may be a consumable item on which a print marker is displayed and no gap G is provided, and the consumable item M1 does not need to be connected to the printing medium B by an expandable and contractible connecting member 72 (the connecting member 72 does not need to be expandable and contractible). Furthermore, the sensor provided in the sensor unit 8 may be a transmissive optical sensor, a reflective optical sensor, a capacitive sensor, or an ultrasonic sensor. Furthermore, the connecting member 72 may be singular, and may be formed of an appropriate elastic member instead of a bellows structure. In addition, the cutting unit 40 may have, as necessary, a half-cutter for half-cutting the upper surface of the consumable item M1 and a full-cutter for fully cutting the consumable item M1, depending on the form of the consumable item M1. [Explanation of Symbols]

[0054] 1...Main unit, 1B...Rear, 1F...Front, 1SL...Left side, 1SR...Right side, 2...Lid, 2B...Rear, 2F...Front, 2SL...Left side, 2SR...Right side, 3...Display / Input / Output unit, 4...Operation buttons, 5...Connector unit, 6...Operation unit, 7...Attachment, 8...Sensor unit (detection unit), 10...Platen unit (transport unit), 11...Shaft, 12...Cylindrical roller, 13...Transport motor, 20, 21, 22...Guide, 30...Encoder unit, 40...Cut unit, 50...Ink ribbon unit, 51...Bobbin, 52...Cassette, 60...Printer head (printing unit), 71...Legs, 71t...Lower end, 72...Connecting member, 81...Sensor unit, 81...Sensor 81H…Light-emitting part, 81J…Light-receiving part, 82…Reflector, 100…Printer, 110…Control unit, 120…Memory (storage unit), 130…Storage, 140…Interface, B, B1, B2, B3…Printing medium, C…Width direction center, D…Forward transport direction, E1…Locking receiver, E2…Locking claw, G, G12, G23…Gap, J…Bearing part, L1…Curve (waveform of detection signal), M1…Consumables, P…Light, PG…Platen gear, R…Ink ribbon, Sa…Short side, Sb, Sb1, Sb2…Long side, SI…Inlet, SO…Outlet, SP1, SP2…Singularity, Ss…Side wall, W12, W23…Gap width, Wa…Short side length, X0…X coordinate of tip position, X1, X2…X coordinate of singularity

Claims

1. A transport unit that transports multiple printing media connected with gaps between them in a predetermined transport direction, A detection unit that outputs a detection signal capable of detecting the position of the printing medium and the gap, A printing unit that prints print information onto the printing medium starting from the printing start position, A control unit that controls the transport unit, the detection unit, and the printing unit, Equipped with, The control unit determines the print start position based on the detection signal. Printer.

2. The control unit identifies a reference position based on the position of the printing medium and the gap, obtains the leading edge position of the printing medium in the transport direction based on the reference position, and determines the printing start position based on the leading edge position. The printer according to claim 1.

3. The printer according to claim 2, wherein the control unit identifies the center in the width direction of the printing medium as the reference position and calculates the tip position based on the reference position and the width direction dimension of the printing medium.

4. The printer according to claim 3, wherein the control unit obtains a singularity indicating the position of the gap from the rising and falling portions of the waveform of the detection signal, and identifies the center in the width direction as the reference position from the singularity.

5. The printer according to claim 4, wherein the control unit detects the singularity based on the slope or curvature before and after the peak in the waveform of the detection signal.

6. The printer according to claim 5, wherein the control unit detects the maximum gradient point or inflection point before and after the peak in the waveform of the detection signal as the singular point.

7. The printer according to claim 1, wherein the detection unit has a through-type or reflective optical sensor, a capacitive sensor, or an ultrasonic sensor.

8. The aforementioned printing media are connected via connecting members, The connecting member is formed to be expandable and contractible in the transport direction. The printer according to claim 1.

9. A control method for a printer comprising a transport unit, a detection unit, a printing unit, and a control unit, The transport unit transports a plurality of printing media connected with gaps between them in a predetermined transport direction. The detection unit outputs a detection signal capable of detecting the position of the printing medium and the gap, The printing unit prints the printing information onto the printing medium starting from the printing start position. The control unit identifies a reference position for determining the printing start position based on the detection signal, obtains the leading edge position of the printing medium in the transport direction based on the reference position, and determines the printing start position based on the leading edge position. How to control the printer.

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