Printer

Abstract

To improve accuracy of a position at which printing of information on each printing medium is started, in printing the information on each printing medium of a continuous body including a belt-like mount and a plurality of printing media detachably attached onto the mount with an interval.SOLUTION: A printer according to one embodiment of the present invention comprises: a transport roller which transports a continuous body; a thermal head which has a projected heat generating portion and which holds the transport roller and the continuous body and prints information on a printing medium; a position identifying portion which identifies whether the heat generating portion is on a mount or on the printing medium; and a control portion which controls transportation of the continuous body by the transport roller in such a manner that the heat generating portion is positioned at a position at which printing on the printing medium is started, on the basis of a timing at which a position of the heat generating portion is shifted from a position on the mount to a position on the printing medium or a timing at which the position is shifted from the position on the printing medium to the position on the mount.SELECTED DRAWING: Figure 9

Description

[Technical field]

[0001] The present invention relates to a printer. [Background technology]

[0002] Conventionally, in a printer that transports continuous paper on which printing media such as labels are removably attached at intervals to a strip-shaped backing, there is known a printer that is provided with a sensor for detecting the printing medium when printing information such as letters, symbols, figures or bar codes on the printing medium. For example, Patent Document 1 describes a printer that has a sensor that detects the position of continuous paper transported to the top surface of a paper guide section, and is configured to print desired information on a label on the continuous paper by timing the printing based on the information detected by the sensor. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-73025 A Summary of the Invention [Problem to be solved by the invention]

[0004] In conventional printers, the sensor for detecting the print medium is installed at a relatively distant position upstream of the thermal head that performs printing on the print medium transport path. For example, in the printer described in the above-mentioned Patent Document 1 (see FIG. 9), a sensor unit including a sensor is installed at a relatively distant position upstream of the platen roller that holds the thermal head and the label when printing. Therefore, there may be cases where the accuracy of the print start position on the print medium based on the detection result of the sensor is not sufficient. The reasons for this are as follows.

[0005] The diameter of the platen roller of the printer expands or contracts with temperature changes, and contracts due to wear. In addition, when a print medium is transported, a large roll of paper is subject to a large transport load, making it slippery, especially at the point where the print medium is clamped between the thermal head and the platen roller at the start of transport. Therefore, even if the amount of rotation of the platen roller for transporting the continuous paper from the sensor detection position to the print start position is preset based on the physical distance, it may be slightly misaligned with respect to the print start position. In addition, when the distance of the transport path between the sensor detection position and the print start position is long, the amount of rotation of the platen roller that is set increases, so the influence of fluctuations in the diameter of the platen roller and slippage accumulates, and the deviation of the print start position may become significant. In particular, when the length of one label (print medium) in the transport direction is short and multiple labels are included between the sensor detection position and the thermal head, the platen roller is rotated forward and backward many times, which increases the effective transport amount, and the deviation of the print start position tends to become more noticeable.

[0006] Therefore, the present invention aims to improve the accuracy of the printing start position for each printing medium when printing information on each printing medium of a continuous body including a band-shaped backing paper and multiple sheets of printing medium removably attached at intervals on the backing paper. [Means for solving the problem]

[0007] One aspect of the present invention is a printer that stores a continuous body including a band-shaped backing and a plurality of sheets of print media releasably attached to the backing at intervals, the printer comprising: A conveying roller for conveying the continuous body; a thermal head having a convex heat generating portion and sandwiching the continuous body between the conveying roller and the thermal head to print information on the print medium; a position specifying unit that specifies whether the heat generating unit is on the mount or on the print medium; a control unit that controls the transport of the continuous web by the transport roller so that the heat generating unit is positioned at a print start position for the print medium based on a timing when the position of the heat generating unit changes from above the backing paper to above the print medium, or a timing when the position of the heat generating unit changes from above the print medium to above the backing paper; It is a printer equipped with. Effect of the Invention

[0008] According to one aspect of the present invention, when printing information on each piece of printing media in a continuous strip including a band-shaped backing and multiple sheets of printing media removably attached at intervals on the backing, the accuracy of the start printing position for each printing medium is improved. [Brief description of the drawings]

[0009] [Figure 1] 1 is a perspective view of a printer according to an embodiment. [Diagram 2] FIG. 1 is a perspective view of a printer according to an embodiment with the interior visible, along with the configuration of continuous paper. [Diagram 3] FIG. 1 is a side view of a printer according to one embodiment with an internal view. [Figure 4] FIG. 4A is a perspective view of the printing unit when the print head unit is in a closed state, and FIG. 4B is a perspective view of the printing unit when the print head unit is in an open state. [Diagram 5] FIG. 2 is a perspective view of a portion of a head mechanism of the printer according to the embodiment. [Figure 6] FIG. 6 is an exploded perspective view of a portion of the head mechanism shown in FIG. 5. [Figure 7] FIG. 6 is an exploded perspective view of a part of the head mechanism not shown in FIG. [Figure 8] FIG. 2 is a diagram illustrating a head mechanism of a printer according to an embodiment. [Figure 9] 11A and 11B are diagrams illustrating the operation of the displacement sensor when the heat generating portion of the thermal head is on a backing sheet and when it is on a label. [Figure 10] FIG. 2 is a functional block diagram of a printer according to an embodiment. [Figure 11]11A and 11B are diagrams illustrating the operation when the continuous paper is set to the print start position by backfeeding. [Figure 12] 11A and 11B are diagrams illustrating the change in the oscillation angle when the heat generating portion of the thermal head is on a backing sheet and when the heat generating portion is on a label. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] The embodiments described below are not limited to the drawings which are illustrated by the brief description of the drawings.

[0011] A first aspect of the present invention is a printer that stores a continuous body including a band-shaped backing and a plurality of sheets of print media releasably attached to the backing at intervals, the printer comprising: A conveying roller for conveying the continuous body; a thermal head having a convex heat generating portion and sandwiching the continuous body between the conveying roller and the thermal head to print information on the print medium; a position specifying unit that specifies whether the heat generating unit is on the mount or on the print medium; a control unit that controls the transport of the continuous web by the transport roller so that the heat generating unit is positioned at a print start position for the print medium based on a timing when the position of the heat generating unit changes from above the backing paper to above the print medium, or a timing when the position of the heat generating unit changes from above the print medium to above the backing paper; It is a printer equipped with.

[0012] According to a first aspect of the present invention, the timing when the position of the heat generating part of the thermal head changes from above the backing paper to above the print medium, or from above the print medium to above the backing paper, is used as a reference, so that the transport distance of the transport roller from that timing to the print start position on the print medium can be relatively short, thereby improving the accuracy of the print start position.

[0013] A second aspect of the present invention is a printer according to the first aspect, further comprising a displacement sensor that detects displacement of the heat generating portion in a direction perpendicular to the surface of the backing paper, and the identification unit identifies the position of the heat generating portion based on the detection result of the displacement sensor.

[0014] According to the second aspect of the present invention, the change in the position of the heat generating part of the thermal head can be identified with high accuracy based on the displacement detected by the displacement sensor.

[0015] A third aspect of the present invention is the printer according to the second aspect, further comprising a mounting portion to which the thermal head is attached, and the displacement sensor detects displacement of the mounting portion.

[0016] According to a third aspect of the present invention, the displacement of the thermal head is detected based on the displacement of the mounting portion of the thermal head, so that the degree of freedom in mounting the displacement sensor can be improved.

[0017] A fourth aspect of the present invention is a printer described in the second or third aspect, wherein the displacement sensor is positioned in the mounting portion at a position that overlaps with the heat generating portion when viewed from a direction perpendicular to the mounting surface of the thermal head.

[0018] According to a fourth aspect of the present invention, the displacement of the heat generating portion of the thermal head is accurately reflected in the displacement of the mounting portion, so that the change in position of the heat generating portion of the thermal head can be identified with high precision.

[0019] A fifth aspect of the present invention is a printer according to any one of the second to fourth aspects, further comprising a pivot shaft that pivots the mounting portion, and the displacement sensor is positioned such that the distance from the pivot shaft to the displacement sensor is the same as or farther than the distance from the pivot shaft to the heat generating portion.

[0020] According to a fifth aspect of the present invention, the displacement sensor is disposed at a position relatively far from the oscillation axis, so that the amount of displacement detected becomes relatively large, and a displacement sensor with low resolution can be used.

[0021] A sixth aspect of the present invention is a printer according to the first aspect, comprising a mounting portion to which the thermal head is attached, a swing shaft for swinging the mounting portion, and an angle sensor for detecting changes in the angle of the swing shaft, wherein the identification portion identifies the position of the heat generating portion based on the detection result of the angle sensor.

[0022] According to a sixth aspect of the present invention, even if a displacement sensor cannot be mounted in the vicinity of the thermal head, the position of the heat generating portion can be substantially identified by the angle sensor.

[0023] A seventh aspect of the present invention is a printer described in any one of the first to sixth aspects, wherein the control unit rotates the conveying roller in a reverse direction so that the heating element is positioned at the printing start position relative to the printing medium, based on the timing when the position of the heating element changes from on the printing medium to be printed onto the backing paper.

[0024] According to a seventh aspect of the present invention, by using the timing at which the position of the heat generating part of the thermal head changes from above the printing medium to be printed onto the backing paper as a reference, the heat generating part can be positioned at the printing start position with greater accuracy.

[0025] An eighth aspect of the present invention is a printer described in any one of the first to seventh aspects, further comprising an input unit that accepts operational input of an adjustment amount for the print start position in the transport direction of the continuous body or in the direction opposite to the transport direction, and the control unit changes the print start position based on the adjustment amount.

[0026] According to an eighth aspect of the present invention, it becomes possible to finely adjust the print start position in response to a request from a printer user.

[0027] Hereinafter, the embodiments will be described in detail with reference to the drawings. Figure 1 shows the external appearance of a printer 1 according to an embodiment. For ease of explanation, XYZ coordinates are defined below as shown in Figure 1. That is, +X and -X respectively indicate the left-right direction of the printer 1, +Y and -Y respectively indicate the front-rear direction of the printer 1, and +Z and -Z respectively indicate the up-down direction of the printer 1. An issuing port 5 for issuing (discharging) printed labels is provided in a front cover 2 on the front side of the printer 1. An open cover 6 is attached to one side of the printer 1 by two hinges 7 so that it can be opened and closed freely in the vertical direction.

[0028] 2 and 3 are respectively a perspective view and a side view of the main part of the printer 1 with the inside visible. Inside the printer 1, there are arranged a paper supply unit 10 located at the rear, a printing unit 11 located at the front, and an ink ribbon unit 12 located above.

[0029] The paper supply unit 10 is loaded with roll paper R. As shown in FIG. 2, the roll paper R is a continuous paper CP wound into a roll. The continuous paper CP includes a strip-shaped backing paper PM and a plurality of labels PL removably attached to the backing paper PM at intervals. The surface of the backing paper PM that comes into contact with the adhesive surface of the labels PL is coated with a release agent such as silicone, making it possible to easily peel off the labels PL. In addition, position detection marks indicating the position of the labels are formed at predetermined intervals along the longitudinal direction on the surface of the backing paper PM where the labels PL are not attached. The labels PL may be thermal paper or regular paper. In the case of thermal paper, a thermal coloring layer is formed on the surface of the paper that turns a specific color (black, red, etc.) when a predetermined temperature range is reached.

[0030] The paper supply unit 10 includes a support shaft 10a and a roll guide 10b, and holds the roll paper R and supplies the continuous paper CP paid out from the roll paper R to the printing unit 11. The support shaft 10a supports the roll paper R in a freely rotatable state. The roll guide 10b fixes the roll paper R and is installed in a freely movable state along the axial direction of the support shaft 10a so that its position can be changed according to the width of the roll paper R.

[0031] There are two types of continuous paper CP: front-wound labels and back-wound labels. Front-wound labels are wound with the label PL of the continuous paper CP located on the outer periphery of the roll paper R, and as shown in FIG. 3, the continuous paper CPs (dashed line) is fed from around the center of the height of the paper supply unit 10 toward the bottom of the printing unit 11. In contrast, back-wound labels are wound with the label PL of the continuous paper CP located on the inner periphery of the roll paper R, and as shown in FIG. 3, the continuous paper CPb (solid line) is fed from around the inner bottom of the printer 1 toward the bottom of the printing unit 11. Note that the paper feed route of the continuous paper CP (CPs, CPb) in the printing unit 11 is the same whether it is front-wound or back-wound. Whether it is front-wound or back-wound, the continuous paper CP is transported with the label PL facing the printing side up.

[0032] The printing unit 11 includes a print head unit 13, a support stand 14 arranged below the print head unit 13, and a damper 15, and performs printing on the labels PL of the continuous paper CP. The print head unit 13 is installed inside the printer 1 in a state in which it can be opened and closed freely, as described below. When the print head unit 13 is in a closed state, a paper passage route is formed between the print head unit 13 and the support base 14. The paper passage route is connected to the issuing port 5 (see FIG. 1). A head lock lever 16 that maintains the closed state of the print head unit 13 is installed on the support base 14. When the head lock lever 16 is operated, the closed state of the print head unit 13 is released, the front part of the print head unit 13 is lifted, and the print head unit 13 opens (moves away from the platen roller 23). Damper 15 applies tension to the continuous paper CP. In this embodiment, damper 15 includes outer damper 15a and inner damper 15b, and moves up and down (opens and closes) in conjunction with the opening and closing of print head unit 13. However, when print head unit 13 is in the closed state, outer damper 15a and inner damper 15b are installed in a state in which they can freely swing so that they can apply tension to the continuous paper CP.

[0033] The ink ribbon unit 12 includes a ribbon supply unit 12a and a ribbon winding unit 12b, and supplies and winds up the ink ribbon RB coated with printing ink. The ribbon supply unit 12a supports the ink ribbon RB wound in a roll so that it can rotate freely. The ribbon winding unit 12b winds up and collects the ink ribbon RB after printing. When the ink ribbon RB is used, the ink ribbon RB pulled out from the ribbon supply unit 12a is passed under the print head unit 13 and wound up by the ribbon winding unit 12b.

[0034] In this printer 1, the continuous paper CP (CPs, CPb) fed from the roll paper R in the paper supply unit 10 is transported to the paper route between the print head unit 13 and the support table 14 via the damper 15, and a printing process is performed on the label PL of the continuous paper CP along the way. After the printing process, the continuous paper CP is discharged from the issue port 5 to the outside of the printer 1.

[0035] Next, the configuration of the above-mentioned printing unit 11 will be described with reference to FIGS. 4A to 6. FIG. Fig. 4A is a perspective view of the printing unit 11 when the print head unit 13 is in a closed state, and Fig. 4B is a perspective view of the printing unit 11 when the print head unit 13 is in an open state. Fig. 5 is a perspective view of the main parts of a head mechanism unit 35 provided in the printing unit 11. Fig. 6 is an exploded perspective view of the main parts of the head mechanism unit 35 in Fig. 5.

[0036] As shown in FIGS. 4A and 4B, the print head unit 13 is supported by a head support plate 17 in a state in which it can freely swing (that is, open and close) around the X axis centered on a swing shaft S1 provided at the rear.

[0037] On the underside (surface facing the paper feed route) of the print head unit 13, a thermal head 18 is installed with its heat generating portion 18L (see FIG. 6) facing the paper feed route. The heat generating portion 18L of the thermal head 18 is formed of a glaze layer that protrudes a predetermined amount (e.g., several tens of μm) from the substrate of the thermal head 18, includes a plurality of heat generating resistors (heat generating elements) that generate heat when energized, and performs printing on the label PL of the continuous paper CP. The plurality of heat generating resistors are aligned and arranged along the width direction of the continuous paper CP (direction perpendicular to the transport direction of the continuous paper CP).

[0038] Concave claws 19, 19 (see FIG. 4B) are provided on the underside of the front side of the print head unit 13 so as to sandwich the thermal head 18. Behind the concave claws 19 on the underside of the print head unit 13, pins 20, 20 are provided which protrude outward from both side surfaces of the print head unit 13.

[0039] The print head unit 13 is biased in the open direction by a torsion spring (not shown) attached to the swing shaft S1, but is maintained in a closed state by locking claws 22, 22 of the support base 14 hooking onto pins 20, 20 at the bottom of the print head unit 13. When the head lock lever 16 is operated rearward, the locking claw 22 moves rearward in conjunction with this and disengages from the pin 20. When the locking claw 22 disengages from the pin 20, the print head unit 13 is designed to automatically open due to the biasing force of the torsion spring (not shown), as shown in Figure 4B.

[0040] When the print head unit 13 is in the closed state, the concave claws 19, 19 (see FIG. 4B) of the print head unit 13 are fitted onto both ends of the rotation shaft S2 of the platen roller .

[0041] The platen roller 23 transports the continuous paper CP fed from the paper supply unit 10 along a paper passage route to the issue port 5 (see FIG. 1). The platen roller 23 is installed on the upper part of the support base 14 in a state in which it can rotate in both forward and reverse directions, and during printing, it rotates while clamping the continuous paper CP together with the thermal head 18. A gear G1 is connected to one axial end of the rotation shaft S2 of the platen roller 23. This gear G1 is engaged with the rotation shaft of a stepping motor, for example, via a timing belt (not shown) or the like.

[0042] Next, the head mechanism provided in the print head unit 13 will be described with reference to FIGS. Fig. 5 is a perspective view of a main part of the head mechanism 35. Fig. 6 is an exploded perspective view of a main part of the head mechanism 35 of Fig. 5. Note that Fig. 5 virtually illustrates a displacement sensor 60, which will be described later. As shown in FIG. 6, the head mechanism section 35 (an example of a mounting section to which the thermal head 18 is attached) has a head slider section 36 and a head holding section 37 in this order from the bottom.

[0043] The head slider unit 36 ​​is a mechanical unit that moves the position of the heat generating part 18L of the thermal head 18 back and forth (forward and backward along the transport direction of the continuous paper CP) depending on the type of printing medium (thickness, hardness, etc.), and has a lower plate 36a, an upper plate 36b, a rotating shaft 36c, and a gear 36d. The lower plate 36a is detachably fixed by screws 36e to the rear surface (surface behind the printing surface) of the thermal head 18. At the front side of the lower plate 36a, both ends in the longitudinal direction (width direction of the continuous paper CP) of the lower plate 36a are partially bent upward, and concave claws 36f, 36f are formed at the upper tips. An upper plate 36b is placed on the lower plate 36a. A rotating shaft 36c is supported on the upper plate 36b in a freely rotatable state. Concave claws 36f, 36f of the lower plate 36a are fitted into both ends of the rotating shaft 36c in the longitudinal direction. This allows the lower plate 36a to engage with the rotating shaft 36c.

[0044] A gear 36d is connected to one end of the rotating shaft 36c. The part of the rotating shaft 36c into which the concave claw 36f is fitted is eccentric to the rotating shaft part between them and the center of the gear 36d. Therefore, when the gear 36d is rotated, the lower plate 36a engaged with the rotating shaft 36c moves back and forth. This allows the position of the heat generating part 18L of the thermal head 18 to be changed to an optimal position depending on the type of label PL (thickness, hardness, etc.), thereby improving the print quality.

[0045] The upper plate 36b has a hole 36g (see FIG. 6) that penetrates from the top to the bottom. A protrusion 18P provided on the back surface of the thermal head 18 is inserted into the hole 36g.

[0046] The head holding portion 37 has a pressing plate 37a and a coil spring 37b, and holds the thermal head 18 in a detachable state. The pressure plate 37a is installed on the upper plate 36b by screws 37c, 37c in a state in which it can move slightly along its longitudinal direction (the width direction of the continuous paper CP). The pressure plate 37a is formed with a hole 37d penetrating its upper and lower surfaces. The protrusion 18P of the thermal head 18 is inserted into the hole 37d. One longitudinal end of the pressure plate 37a is bent downward, and a head retention release portion 37e (see FIG. 6) is formed at that end. The lower tip of the head retention release portion 37e protrudes from the underside of the print head unit 13. The coil spring 37b is attached between the screws 37c, 37c. The pressing plate 37a is biased by the coil spring 37b in a direction in which the pressing plate 37a presses the protrusion 18P. In this way, the thermal head 18 is held in place.

[0047] When removing the thermal head 18, the head retention release portion 37e of the retaining plate 37a is moved in the opposite direction against the biasing force of the coil spring 37b to release the retaining plate 37a from pressing down on the protrusion 18P. On the other hand, when attaching the thermal head 18, the thermal head 18 is pushed in with the protrusion 18P inserted into the holes 36g and 37d. This makes it easy to attach and detach the thermal head 18.

[0048] Next, the pressing mechanism 38 and the displacement sensor 60 included in the head mechanism unit 35 will be described with reference to Fig. 7. Fig. 7 is an exploded perspective view of the pressing mechanism 38 and the displacement sensor 60 of the head mechanism unit 35. The pressing mechanism 38 and the displacement sensor 60 are disposed further above the pressing plate 37a (Fig. 6). As shown in FIG. 7, the pressing mechanism 38 includes a pair of head pressing plates 50, a pair of coil springs 44, and a support plate 41 fixed to the print head unit 13. The head holding plate 50 is configured to be able to swing around a swing shaft 51. Both ends of the swing shaft 51 are inserted into a pair of holes 41h provided in the support plate 41. A protrusion 50c that comes into contact with the thermal head 18 is provided on the distal end of the swing shaft 51 of the head holding plate 50. A coil spring 44 is attached between the top surface of the head pressing plate 50 and the support surface 41s, which is the bottom surface of the support plate 41. As a result, the restoring force of the coil spring 44 acts on the thermal head 18 through the protrusion 50c of the head pressing plate 50, so that the thermal head 18 can generate an appropriate pressing force against the platen roller 23 while sandwiching the continuous paper CP between the thermal head 18 and the platen roller 23. Note that the pressing mechanism 38 may be provided with a pressing force adjustment mechanism. For an example of providing a pressing force adjustment mechanism, see JP 2015-123628 A by the applicant of the present application.

[0049] As shown in FIG. 7, a displacement sensor 60 is attached to the support surface 41s of the support plate 41. The displacement sensor 60 is a sensor that detects the displacement of the heat generating part 18L of the thermal head 18 in a direction perpendicular to the surface of the backing paper PM. In one embodiment, the displacement sensor 60 is a contact type displacement sensor, has a movable part 61 as a pickup, and detects the displacement of the heat generating part 18L of the thermal head 18 based on the displacement of the movable part 61. The displacement sensor 60 is arranged so that the tip of the movable part 61 contacts the upper surface 36s (see FIG. 5) of the upper layer plate 36b. When the position of the heat generating part 18L of the thermal head 18 is displaced from the backing paper PM to the label PL, or from the label PL to the backing paper PM while the continuous paper CP is being transported, the upper surface 36s of the upper layer plate 36b is displaced in accordance with the displacement of the heat generating part 18L, and the movable part 61 is displaced, so that the displacement amount of the heat generating part 18L of the thermal head 18 can be known. In other words, in this embodiment, the displacement of the heat generating part 18L is indirectly detected by detecting the displacement of a part of the head mechanism part 35 that moves in conjunction with the thermal head 18, thereby improving the freedom of implementation of the displacement sensor 60. The displacement sensor 60 may be attached to the support surface 41s of the support plate 41 by any known method, for example, by using an adhesive.

[0050] 8 is a schematic side view showing the positional relationship between the head mechanism 35 and its peripheral components. As shown in FIG. 8, the biasing force of the coil spring 44 does not act on the lower plate 36a, the upper plate 36b, or the pressing plate 37a, but acts only on the protrusion 50c of the head pressing plate 50 to press the thermal head 18 against the platen roller 23. On the other hand, the movable part 61 of the displacement sensor 60 attached to the support plate 41 is in contact with the upper surface 36s of the upper plate 36b. When the thermal head 18 is displaced in a direction perpendicular to the surface of the continuous paper CP, the upper surface 36s of the upper plate 36b is displaced accordingly, and the movable part 61 moves in that direction, so that the displacement sensor 60 can detect the amount of displacement of the heat generating part 18L of the thermal head 18 in the direction perpendicular to the continuous paper CP (i.e., the up-down direction on the paper surface of FIG. 8).

[0051] Next, with reference to FIG. 9, the operation of the displacement sensor 60 when the heat generating portion 18L of the thermal head 18 is on the mount PM and when it is on the label PL will be described. As shown in FIG. 9, when the position of the heat generating part 18L of the thermal head 18 changes from the mount PM to the label PL in the transport state of the continuous paper CP, the thermal head 18 is displaced in a direction perpendicular to the surface of the mount PM by the thickness of the label PL, and the movable part 61 of the displacement sensor 60 is displaced accordingly (displacement amount D). When this displacement amount D is equal to or greater than a predetermined threshold, it can be determined that the position of the heat generating part 18L has changed from the mount PM to the label PL, or from the label PL to the mount PM. The threshold is set to an appropriate value according to the thickness of the label PL so as not to cause erroneous detection due to dust that may be present on the mount PM. As described above, in the printer 1 of this embodiment, by observing the displacement amount of the displacement sensor 60, it is possible to identify whether the heat generating part 18L is on the mount PM or on the label PL.

[0052] Next, the configuration of the printer 1 of this embodiment will be described with reference to the block diagram of FIG. As shown in FIG. 10, the control unit 8 of the printer 1 includes a CPU 81, a ROM 82, a RAM 83, an input interface (I / F) 84, a display control unit 85, a motor controller 86, a head controller 87, a sensor interface (I / F) 88, and a communication bus 89. The CPU 81 loads firmware stored in the ROM 82 into the RAM 83 and executes it to realize various functions of the printer 1. The input interface 84 is an interface that accepts operational inputs made to the input buttons 3 (not shown in FIG. 1; for example, a power button, directional key buttons, etc.) and transmits them to the CPU 81. The display control unit 85 displays an image on the display panel 4 (not shown in FIG. 1) based on the display data received from the CPU 81. The motor controller 86 includes a drive circuit that drives the stepping motor 9 based on a control signal sent from the firmware. The control signal includes, for example, information on the number of steps corresponding to the transport amount of the continuous paper CP. The head controller 87 includes an image buffer, and controls the flow of current selectively to a plurality of heating elements of the thermal head 18 in accordance with print data, based on a control signal (eg, a strobe signal) sent from the firmware. The sensor interface 88 receives the detection result (amount of displacement) of the displacement sensor 60 from the displacement sensor 60, converts it into a digital value, and transmits it to the CPU 81.

[0053] In one embodiment, the control unit 8 functions as a position specifying unit that specifies whether the heat generating unit 18L of the thermal head 18 is on the mount PM or on the label PL based on the detection result (amount of displacement) of the displacement sensor 60. This allows the change in the position of the heat generating unit 18L of the thermal head 18 to be specified with high accuracy. The control unit 8 controls the transport of the continuous paper CP by the platen roller 23 so that the heating unit 18L is positioned at the print start position of the label PL. In principle, the print start position is the leading edge of the label PL on the downstream side in the transport direction. If necessary, the print start position may be adjusted by an offset adjustment function (described later) so that the print start position is a user-specified distance, upstream or downstream, from the leading edge of the label.

[0054] In one embodiment, the control unit 8 controls the transport of the continuous paper CP by the platen roller 23 so that the heating unit 18L is positioned at the printing start position for the label PL based on the timing when the position of the heating unit 18L of the thermal head 18 changes from above the backing paper PM to above the label PL, or from above the label PL to above the backing paper PM.

[0055] In one embodiment, transport by the platen roller 23 is stopped when the position of the heat generating part 18L of the thermal head 18 changes from above the backing paper PM to above the label PL. Since the print start position of the label PL to be printed is in principle the downstream leading edge of the label PL, stopping transport at this timing makes the position of the heat generating part 18L the print start position, and it is possible to improve the accuracy of the print start position when actually printing.

[0056] In one embodiment, the control unit 8 may control the platen roller 23 to rotate in the reverse direction so that the heating element 18L is positioned at the printing start position of the label PL, based on the timing when the position of the heating element 18L of the thermal head 18 changes from on the label PL to be printed onto the backing paper PM. This control will be described with reference to FIG. 11. In FIG. 11, it is assumed that the labels PL1, PL2, PL3, ... are peelably attached on the backing paper PM in this order, and the label PL1 is the label to be printed. When the state ST2 is reached by backfeeding the continuous paper CP, this is the timing when the position of the heat generating part 18L of the thermal head 18 changes from on the label PL to on the backing paper PM. At this timing, the backfeed by the platen roller 23 is stopped. Since the print start position of the label PL to be printed is, in principle, the downstream leading edge of the label PL, by stopping the backfeed at this timing, the position of the heat generating part 18L becomes the print start position, and the accuracy of the print start position when actually printing can be improved. Alternatively, the following control may be used. State ST1 corresponds to the timing when the displacement sensor 60 detects that the position of the heat generating part 18L has changed from on the label PL to on the backing paper PM in the transport state (forward feed) of the continuous paper CP (that is, the heat generating part 18L has reached the rear end position of the label PL1 (the rear end position in the transport direction)). Then, the continuous paper CP may be fed back by the length of the label PL1 so that the position of the heat generating portion 18L is positioned at the print start position of the label PL1 (in this case, the position of the leading edge of the label PL1 in the transport direction) (state ST2).

[0057] The control unit 8 detects the leading edge position of the label PL in the transport direction at the timing when the position of the heat generating unit 18L changes from on the mount PM to on the label PL, and sets the leading edge position as the print start position. Also, the print start position may be set by backfeeding as shown in Figure 11. The reason for this is as follows. The detection result of the displacement sensor 60 tends to be more accurate when the position of the heat generating part 18L changes from on the label PL to on the liner PM than when the position changes from on the liner PM to on the label PL1. This is thought to be because the thermal head 18 is pressed toward the platen roller 23 by the coil spring 44 (see FIG. 8), so the displacement of the heat generating part 18L in the direction from the label PL to the liner PM (i.e., the direction toward the platen roller 23) is clearly indicated. Therefore, the accuracy of the print start position is higher when the continuous paper CP is fed back based on the timing when the position of the heat generating part 18L changes from on the label PL to on the liner PM.

[0058] In one embodiment, the printer 1 is equipped with an angle sensor that detects changes in the angle of the oscillating axis S1 instead of the displacement sensor 60, and the control unit 8 identifies the position of the heating element 18L (whether it is on the backing paper PM or on the label PL) based on the detection result of the angle sensor. 12 shows the change in angle (θ) from the oscillation axis S1 of the head mechanism unit 35 when the heat generating unit 18L of the thermal head 18 is on the mount PM (solid line) and when it is on the label PL (dotted line). Note that in FIG. 12, the displacement sensor 60 is shown virtually. As shown in FIG. 12, the displacement of the heat generating unit 18L of the thermal head 18 causes an angle change of the oscillation axis S1, so by providing a sensor on the oscillation axis S1 that detects the angle change of the oscillation axis S1, the position of the heat generating unit 18L (whether it is on the mount PM or on the label PL) can be practically identified. For example, when there is no space to mount a displacement sensor, an angle sensor may be mounted on the oscillation axis S1 instead of the displacement sensor.

[0059] In one embodiment, the displacement sensor 60 is disposed at a position overlapping with the heat generating part 18L of the thermal head 18 (for example, directly above the heat generating part 18L) when viewed from a direction perpendicular to the mounting surface of the thermal head 18 (corresponding to the lower surface of the lower plate 36a in FIG. 6) in the head mechanism part 35. This allows the displacement of the heat generating part 18L of the thermal head 18 to be accurately reflected in the displacement of the upper plate 36b, so that the change in the position of the heat generating part 18L of the thermal head 18 can be accurately identified. The position where the displacement sensor 60 is disposed may be set to any position depending on the layout with other components. For example, in the example shown in Fig. 8, the displacement sensor 60 is disposed slightly upstream of the heat generating unit 18L in the transport direction, but this is not limiting. The displacement sensor 60 may be disposed downstream of the heat generating unit 18L in the transport direction. The displacement sensor 60 can be disposed at any position in the left-right direction (X-axis direction).

[0060] As described above, the head mechanism unit 35 provided in the print head unit 13 swings around the swing axis S1. In one embodiment, the displacement sensor 60 is disposed at a position where the distance from the swing axis S1 to the displacement sensor 60 (more specifically, the movable unit 61) is equal to or greater than the distance from the swing axis S1 to the heat generating unit 18L. As a result, when the heat generating unit 18L climbs up from the backing paper PM onto the label PL, or when the heat generating unit 18L falls from the label PL onto the backing paper PM, the amount of displacement observed by the displacement sensor 60 becomes equal to or greater than the thickness of the label PL, so that the observed amount of displacement becomes relatively large, and a displacement sensor with low resolution can be used. In order to realize the above-described arrangement of the displacement sensor 60, for example, the upper plate 36b (see FIG. 6) may be extended forward and the displacement sensor 60 may be disposed on the extended portion.

[0061] In one embodiment, the printer 1 may have an offset adjustment function. In the offset adjustment function, the input button 3 (FIG. 10) accepts an operation input from the user regarding an adjustment amount for the print start position in the transport direction of the continuous paper CP or in the direction opposite to the transport direction, and the control unit 8 changes the print start position based on the adjustment amount. This makes it possible to fine-tune the print start position according to the desires of the user of the printer 1.

[0062] Although the embodiment of the printer of the present invention has been described above, the present invention is not limited to the above embodiment. Furthermore, the above embodiment can be improved or modified in various ways without departing from the spirit of the present invention. For example, in the above description, a contact type sensor is given as an example of the displacement sensor, but this is not limiting, and a non-contact type sensor (for example, a laser displacement meter) may also be used.

[0063] In the printer 1 described with reference to the drawings, the head mechanism 35 to which the thermal head 18 is attached is configured to be able to swing around a swing axis S1. Therefore, by detecting the displacement of any one point of the head mechanism 35, it is possible to detect the timing at which the position of the heat generating part 18L of the thermal head 18 is displaced from above the backing paper PM to above the label PL, or the timing at which it is displaced from above the label PL to above the backing paper PM. However, depending on the type of printer, there may be cases where the member to which the thermal head is fixed (head bracket, etc.) does not have a swing axis. Even in such a printer, it is sufficient to detect the displacement of the thermal head itself or the member (head bracket, etc.). [Explanation of symbols]

[0064] 1. Printer 2. Front cover 3...Enter button 4. Display panel 5…Issue port 6…Open cover 7…Hinge 8...Control section 81: CPU, 82: ROM, 83: RAM, 84: input interface, 85: display control unit, 86: motor controller, 87: head controller, 88: sensor interface 9...Stepping motor 10...Paper supply section 10a...Support shaft, 10b...Roll guide 11...Printing section 12...Ink ribbon section 13...Print head unit 14...Support stand 15…Damper 15a...Outer damper, 15b...Inner damper 16...Head lock lever 17...Head support plate 18…Thermal head 18L: Heating part, 18P: Protrusion 19…Concave claw 20…Pin 22...Lock claw 23...Platen roller 35...Head mechanism 36...Head slider section 36a...lower plate, 36b...upper plate, 36c...rotating shaft, 36d...gear, 36e...screw, 36f...concave claw, 36g...hole 37...Head holder 37a...pressure plate, 37b...coil spring, 37c...screw, 37d...hole, 37e...head retention release portion 38...Pressing mechanism 41...Support plate 41h…hole, 41s…support surface 44…Coil spring 50…Head holding plate 50c…Protrusion 51...Oscillating shaft 60...Displacement sensor 61...Movable part CP: Continuous paper PM: Mount, PL: Label RB…Ink ribbon R…Roll paper G1…Gear S1: Oscillation axis, S2: Rotation axis

Claims

1. A printer that stores a continuous body including a strip-shaped backing and a plurality of sheets of print media releasably attached to the backing at intervals, a conveying roller for conveying the continuous body; a thermal head having a convex heat generating portion and sandwiching the continuous body with the conveying roller to print information on the print medium; a position specifying unit that specifies whether the heat generating unit is on the mount or on the print medium; a control unit that controls the transport of the continuum by the transport rollers so that the heat generating unit is positioned at a print start position relative to the print medium, based on the timing when the position of the heat generating unit changes from above the backing paper to above the print medium, or from above the print medium to above the backing paper; A printer equipped with

2. a displacement sensor for detecting a displacement of the heat generating portion in a direction perpendicular to the surface of the mount; the position identifying unit identifies the position of the heat generating unit based on the detection result of the displacement sensor. The printer according to claim 1 .

3. a mounting portion to which the thermal head is attached, The displacement sensor detects a displacement of the mounting portion.

3. The printer according to claim 2.

4. the displacement sensor is disposed at a position on the mounting portion that overlaps with the heat generating portion when viewed from a direction perpendicular to the mounting surface of the thermal head; 4. The printer according to claim 3.

5. a swing shaft for swinging the mounting portion, The displacement sensor is disposed at a position where the distance from the oscillation shaft to the displacement sensor is equal to or greater than the distance from the oscillation shaft to the heat generating portion.

4. The printer according to claim 3.

6. a mounting portion to which the thermal head is attached; a swing shaft that swings the mounting portion; an angle sensor that detects a change in the angle of the swing shaft, the position identification unit identifies the position of the heat generating unit based on the detection result of the angle sensor. The printer according to claim 1 .

7. the control unit rotates the conveyance roller in the reverse direction so that the heat generating unit is positioned at the print start position relative to the print medium, based on the timing when the position of the heat generating unit changes from above the print medium to above the backing sheet. The printer according to any one of claims 1 to 3 and 6.

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