printer

Abstract

To provide a printer that can peel and issue a label, which can be enhanced in workability in replacing a thermal head.SOLUTION: A printer which can peel a label from a mount of a printing medium having the label peelably attached to the mount and then issue the label, comprises: a conveying roller that conveys the printing medium; a printing head that prints information on the label while holding the printing medium together with the conveying roller; and a peeling unit that can move between a position where the unit covers at least a portion of the printing head and a position where the unit does not cover the printing head, while holding the peeling roller opposing to the conveying roller, when peeling the label and issuing the label. The printing head has a pair of shafts extending from both side surfaces to the outside and extends in a predetermined direction, in which a pair of grooves where the pair of shafts can be moved in the predetermined direction are formed. In the printer, a space for pulling out the printing head in the predetermined direction is formed, when the peeling unit is positioned at the position where the unit does not cover the printing head.SELECTED DRAWING: Figure 17

Description

Technical Field

[0001] The present invention relates to a printer.

Background Art

[0002] Generally, a label printer is configured to print desired information on a label while conveying a continuous paper by sandwiching the continuous paper, on which a plurality of labels are temporarily attached to a strip of backing paper, between a thermal head and a platen roller and rotating the platen roller. Conventionally, a label printer capable of switching between two types of issuing methods, continuous issuing and peeling issuing, is known (for example, Patent Document 1). The continuous issuing method is a method of issuing labels while temporarily attaching them to the backing paper, and the peeling issuing method is a method of issuing labels after peeling them from the backing paper. In the printer described in Patent Document 1, continuous issuing and peeling issuing are switched by moving the backing paper pressing roller support frame of the peeler unit (peeling unit) between the first turning position and the second turning position.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, in a printer capable of switching between continuous issuing and peeling issuing, for example, when a defect in printing dots occurs, it is necessary to replace the thermal head. However, conventionally, tools may be required when replacing the thermal head, and it has been difficult to say that the replacement workability is sufficiently good. In particular, in a printer capable of switching between continuous issuing and peeling issuing, since the peeling unit is configured to be movable between the continuous issuing position and the peeling issuing position, the peeling unit may become an obstacle to the replacement work of the thermal head.

[0005] Therefore, the present invention aims to improve the ease of replacing the thermal head in a printer capable of peel-off printing. [Means for solving the problem]

[0006] One aspect of the present invention is a printer capable of peeling off and issuing a label from a backing sheet of a printing medium having a label peelably attached to a backing sheet, comprising: a transport roller for transporting the printing medium; a print head for gripping the printing medium together with the transport roller and printing information on the label; and a peeling unit for holding a peeling roller facing the transport roller when peeling off and issuing the label, and which is movable between a position that covers at least a part of the print head and a position that does not cover the print head, wherein the print head has a pair of shafts extending outward from both sides and extending in a predetermined direction, a pair of grooves formed therein that allow the pair of shafts to move in the predetermined direction, and when the peeling unit is in a position that does not cover the print head, a space is formed for pulling out the print head in the predetermined direction. [Effects of the Invention]

[0007] According to one aspect of the present invention, the ease of replacing the thermal head in a peel-off printer can be improved. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1A is a perspective view of the printer according to the embodiment with the printer cover in the closed state, and Figure 1B is a perspective view of the printer according to the embodiment with the printer cover in the open state. [Figure 2] This is a perspective view of the printer according to the embodiment, with the printer cover open, the release unit open, and no roll paper stored inside. [Figure 3] This is a partial cross-sectional view illustrating continuous printing and peel-off printing in the printer of the embodiment. [Figure 4] This diagram illustrates the mechanism by which the printer cover is opened using the cover release button. [Figure 5] This diagram shows the positional relationship between the platen retaining bracket and the lever group. [Figure 6] This is a perspective view of the peeling unit in the open and closed positions. [Figure 7] This is a perspective view of the delamination unit when it is open, from a different viewpoint than that shown in Figure 6. [Figure 8] This diagram illustrates the relationship between the peeling unit release lever and the peeling unit during continuous printing and when the peeling unit release button is operated. [Figure 9] This diagram illustrates the relationship between the peeling unit release lever and the peeling unit during continuous printing and when the peeling unit release button is operated. [Figure 10] Figure 10A is a plan view of the printer cover of the printer of this embodiment, and Figure 10B is a cross-sectional view AA of Figure 10A. [Figure 11] This is a partially enlarged cross-sectional view of the vicinity of the peeling roller during peeling. [Figure 12] This diagram illustrates the operation of folding the peeling unit. [Figure 13] This diagram illustrates the operation of folding the peeling unit. [Figure 14] This diagram shows the sequence of operations when switching the printer of the embodiment from continuous printing to peel-off printing. [Figure 15] This diagram shows the sequence of operations when switching the printer of the embodiment from continuous printing to peel-off printing. [Figure 16] Figure 16A shows the front of the thermal head, and Figure 16B shows the rear of the thermal head. [Figure 17] This is a cross-sectional view showing enlarged sections AA and BB of Figure 16A. [Figure 18] This is a partial cross-sectional view of a printer including a bearing groove for the thermal head. [Figure 19] This diagram illustrates how to replace the thermal head. [Figure 20] The figure shows a convex portion provided in an inner frame and supporting a thermal head. [Figure 21] The figure illustrates the forces acting on the thermal head in the printer of the embodiment. FIG. 20A shows a cross section in a plane orthogonal to the vertical direction, and FIG. 20B shows a cross section in a plane orthogonal to the left-right direction. [Figure 22] FIG. 22A is a perspective view of a thermal head of another embodiment as viewed from the front, and FIG. 22B is a perspective view of a thermal head of another embodiment as viewed from the rear. [Figure 23] The perspective view of the plate-like member included in the thermal head of another embodiment. [Figure 24] The perspective view of the thermal head of another embodiment when viewed from a different perspective from FIG. 22. [Figure 25] The side view showing the positional relationship between the thermal head of another embodiment and the platen holding bracket.

Embodiments for Carrying Out the Invention

[0009] [Schematic Configuration of Printer 1] The printer 1 according to an embodiment of the present invention is a label printer configured to be able to switch between continuous printing and peeling printing. Hereinafter, the printer 1 will be described in detail with reference to the drawings. In each figure, for example, as shown in the perspective views of FIGS. 1A and 1B, the directions of up (UP), down (DN), left (LH), right (RH), front (FR), and rear (RR) are defined. However, this definition of the directions is solely for the convenience of explaining the drawings and is not intended to limit the posture of the printer of the present invention during use. In this definition of the directions, the "front-rear direction of the printer" means the front-rear direction of the printer 1. The "width direction of the printer" means the left-right direction or the lateral direction of the printer 1.

[0010] Figures 1A, 1B, and 2 are perspective views of the printer 1 of the embodiment, respectively. Figure 1A shows the printer cover 3 in the closed state, while Figures 1B and 2 show the printer cover 3 in the open state. Figure 1B shows the state with the roll paper R set, and Figure 2 shows the state of the printer 1 with the roll paper R and before the roll paper R is set.

[0011] As shown in Figure 1A, the printer 1 has its internal functional components protected by a main body case 2 and a printer cover 3. A label ejection unit 20 is provided on the top surface of the printer 1. In addition, while the printer 1 can be used with the output section 20 facing upwards (horizontal orientation), it can also be used with the output section 20 facing sideways (vertical orientation) by attaching the belt hook (not shown) provided on the bottom of the printer 1 to the operator's belt, or by attaching a shoulder belt (not shown) and suspending it over the operator's shoulder. In the main body case 2, a display panel 15 is provided in front of the output section 20. The display panel 15 may include a touch panel input mechanism that accepts operation input from the operator. The display panel 15 is connected to the circuit board inside the printer 1 and outputs images that show, for example, the operating status of the printer 1 or the user interface related to the operation of the printer 1, based on display signals supplied from the circuit board.

[0012] Although not shown in the diagram, the printer 1, which is enclosed by the main body case 2 and the printer cover 3, contains an internal frame for supporting or holding various functional components. This internal frame, along with the main body case 2 and the printer cover 3, constitutes the printer body.

[0013] The printer cover 3 is configured to swing between an open position that opens the inside of the printer 1 and a closed position that closes the inside of the printer 1. When the cover release button 51b located on the main unit case 2 is operated, the printer cover 3 opens as shown in Figure 1B. Opening the printer cover 3 exposes the roll paper storage compartment 9. The roll paper storage compartment 9 is a space for storing roll paper R (an example of a roll).

[0014] As shown in Figure 2, the roll paper R is made by winding a strip of continuous paper P into a roll. The continuous paper P has a strip of backing paper PM and a number of labels PL that are temporarily attached to the backing paper PM at predetermined intervals. The label attachment surface of the backing paper PM is coated with a release agent such as silicone so that the labels PL can be easily peeled off. In addition, position detection marks M indicating the reference position of the labels PL are formed on the back surface of the label attachment surface of the backing paper PM at predetermined intervals. The front side of the label PL is the printing surface where information is printed, and it has a heat-sensitive color-developing layer that changes to a specific color when it reaches a predetermined temperature range. The back side of the printing surface is the adhesive surface covered with adhesive, and the label PL is temporarily attached to the backing paper PM by sticking this adhesive surface to the label attachment surface of the backing paper PM.

[0015] A pair of roll paper guides 6a are installed in the roll paper storage chamber 9. The pair of roll paper guides 6a are members that support the roll paper R in a rotatable state while in contact with both sides of the roll paper R, and guide the transport of continuous paper drawn from the roll paper R. Preferably, they are movable along the width direction of the roll paper R so that their position can be changed according to the width of the roll paper R.

[0016] As shown in Figure 2, the printer cover 3 is pivotally supported on the main body case 2 by a hinge 8 so that the printer cover 3 can swing relative to the main body case 2 between an open position and a closed position. The hinge 8 has a hinge shaft 81, and a torsion spring (not shown) is provided on the hinge shaft 81 to bias the printer cover 3 from the closed position toward the open position.

[0017] As shown in Figure 2, a platen roller 10 (an example of a transport roller) is pivotally supported at the front of the printer cover 3, allowing it to rotate freely in forward and reverse directions. The platen roller 10 is a transport means for transporting continuous paper P drawn from a roll of paper R, and is formed to extend along the width direction of the continuous paper P. A gear 10b is connected to one end of the platen shaft 10a of the platen roller 10. This gear 10b engages with a gear 22b located inside the main body case 2 when the printer cover 3 is in the closed position, and is mechanically connected to a stepping motor (not shown) for roller driving via the gear 22b.

[0018] As shown in Figure 2, a release bar 12 is installed on the printer cover 3 near the platen roller 10, along the platen roller 10. This release bar 12 is a release member that separates the label PL from the backing paper PM, and both ends of it are fixed to the side walls of the printer cover 3. Alternatively, the release bar 12 may be fixed to both ends of the platen shaft 10a. In one embodiment, the cross-section of the peeling bar 12 is substantially triangular, but it is not limited to that and may be spherical or elliptical.

[0019] Inside the main case 2, there is a platen holding bracket 27 that holds the platen shaft 10a of the platen roller 10 when the printer cover 3 is closed. A thermal head 28 is positioned in front of the platen holding bracket 27.

[0020] The thermal head 28 (an example of a print head) is a printing means that prints information such as characters, symbols, figures, or barcodes onto a label PL that is temporarily attached to a backing sheet PM transported from a roll of paper R. The thermal head 28 is positioned to face the platen roller 10 when the printer cover 3 is closed. As will be described later, the thermal head 28 is detachably fitted with a flexible cable that connects to a circuit board (not shown). The thermal head 28 is equipped with multiple heating elements (heating resistors) arranged along the width direction of the continuous paper P, and prints by selectively energizing the multiple heating elements based on signals transmitted from the circuit board.

[0021] As shown in Figure 2, a coil spring 55 is positioned in front of the thermal head 28. One rear end of the coil spring 55 abuts against the thermal head 28, and the other front end of the coil spring 55 abuts against the internal frame (see also Figure 19). The coil spring 55 biases the thermal head 28 toward the platen roller 10 during printing, thereby pressing the thermal head 28 against the platen roller 10 with the optimal pressure for printing.

[0022] Printer 1 has a peeling unit 4, and performs continuous printing and peeling printing by moving the peeling unit 4 between a continuous printing position and a peeling printing position. As shown in Figure 1B, when the printer cover 3 is in the open position, the peeling unit release button 52b is exposed. By operating the peeling unit release button 52b, the peeling unit 4 can be operated. Figure 2 shows the state of the peeling unit 4 when the peeling unit release button 52b is operated. As will be described later, the button 52b for releasing the peeling unit is operated by the operator when switching from continuous firing to peeling firing.

[0023] As shown in Figure 2, the peeling unit 4 includes a peeling roller cover 41 and a peeling roller holding part 42 that holds the peeling roller 45. The peeling roller cover 41 is configured to cover the peeling roller holding part 42 during continuous firing. The peeling roller cover 41 is pivotally supported on an internal frame within the main body case 2 and swings from a closed position to an open position (the state shown in Figure 2) in response to the operation of the peeling unit release button 52b. The peeling roller holder 42 is pivotally supported by the peeling roller cover 41. During continuous firing, the peeling roller holder 42 is folded and housed beneath the back surface of the peeling roller cover 41. The peeling unit 4 will be described in detail later.

[0024] The printer cover 3 is equipped with a sensor 35. When the printer cover 3 is closed, the sensor 35 is positioned along the paper path from when the continuous paper P is pulled from the roll paper R until it reaches the platen roller 10, and detects the position of the label PL. It is preferable to control the amount of continuous paper P being transported based on the detection result of this sensor 35.

[0025] Although not shown in the diagram, it is advisable to provide a cutter to cut the backing paper PM of the continuous paper P after continuous printing. If a cutter is provided, it will be installed in the discharge section 20 in a state that extends along the width direction of the continuous paper P. Alternatively, the peeling bar 12 may be used as a cutter.

[0026] [Continuous issuance and peel-off issuance] Next, the continuous printing and peel-off printing functions of printer 1 will be explained with reference to Figure 3. Printer 1 is configured to allow switching between peel-and-print, which peels labels from the backing sheet of continuous paper and prints them, and continuous printing, which prints labels without peeling them from the backing sheet.

[0027] For continuous printing, a backing sheet with the required number of labels attached can be prepared, and the labels can be peeled off the backing sheet and applied on-site. This is suitable when the object to which the labels are to be applied is located far from the printer 1. For continuous printing, the peeling unit 4 attached to the printer 1 is set to the continuous printing position.

[0028] On the other hand, in the peel-off printing method, the labels are ejected one by one, peeled from the backing paper, making it suitable when the object to which the labels are to be applied is close to the operator. For peel-off printing, the peel-off unit 4 attached to the printer 1 is set to the peel-off printing position. As a result, when the platen roller 10 is rotated for printing and the continuous paper is transported, the backing paper is transported while sandwiched between the peel-off roller 45 and the platen roller 10, while the printed labels are peeled off the backing paper one by one and ejected outside the printer 1.

[0029] Figure 3 is a schematic partial cross-sectional view showing the positional relationship between the peeling unit 4, platen roller 10, peeling bar 12, and thermal head 28 during continuous and peeling peeling. In Figure 3, the peeling roller cover 41 and peeling roller holding part 42 of the peeling unit 4 are shown only by their outlines. The outline of the peeling roller cover 41 is shown by a dotted line. Furthermore, since the position of the peeling roller holding portion 42 differs between continuous printing and peeling printing, only the peeling roller holding portion 42 is marked with diagonal lines. The position of the peeling unit 4 during continuous printing corresponds to the continuous printing position, and the position of the peeling unit 4 during peel printing corresponds to the peel printing position.

[0030] As shown in Figure 3, during continuous printing, the peel roller holder 42 is housed under the peel roller cover 41, so that the peel roller 45 is positioned away from the platen roller 10 and does not obstruct the discharge of the continuous paper P. The continuous paper P drawn from the roll paper R is held between the platen roller 10 and the thermal head 28, and printed onto the label on the continuous paper P.

[0031] When switching from continuous printing to peel-off printing, the peel-off roller holder 42 is moved to the oscillating position shown in Figure 3, around the axis 42a. As shown in Figure 3, during peel-off printing, the peel-off roller 45 is positioned opposite the platen roller 10. In peel-off printing, the continuous paper P drawn from the roll paper R is held between the platen roller 10 and the thermal head 28, and printing is done on the label on the continuous paper P, just as in continuous printing. In peel-off printing, the backing paper PM of the continuous paper P drawn from the roll paper R is sharply rotated at the peel-off bar 12, and is held between the platen roller 10 and the peel-off roller 45 before being discharged. As the backing paper PM is sharply rotated at the peel-off bar 12, the label PL is peeled off the backing paper PM and discharged.

[0032] [Opening operation of printer cover 3] Next, the operation of opening the printer cover 3 will be explained with reference to Figures 4 and 5. The cover opening lever 51 and the peeling unit opening lever 52 will also be explained.

[0033] Figure 4 shows the cover release lever 51 when the printer cover is closed and when the cover release button is operated, the peeling unit release lever 52 (an example of a swinging member), the platen holding bracket 27 (an example of a locking member), and a side view of the peeling unit 4. In Figure 4, as an example, the case in which the peeling unit 4 is in the continuous printing position is shown. As shown in Figure 4, when viewed from the side, the cover release lever 51 and the peeling unit release lever 52 are positioned opposite each other in the front-to-back direction, while extending in the front-to-back direction at different heights, resulting in a space-efficient arrangement.

[0034] Figure 5 is a perspective view of the cover release lever 51, the peeling unit release lever 52, the platen holding bracket 27, and the peeling unit 4 from a rearward perspective when the printer cover is closed. In Figure 5, the peeling unit 4 is omitted from the illustration.

[0035] The cover release lever 51 has a cover release button 51b that is exposed to the outside, as shown in Figure 1A. The cover release lever 51 has a shaft insertion hole 51a, and this shaft insertion hole 51a is inserted into a shaft portion 56 (not shown in Figure 5) provided in the internal frame. As a result, the cover release lever 51 is configured to swing around the shaft portion 56. As shown in Figure 5, the cover release lever 51 has a projection 51c that protrudes inward.

[0036] As shown in Figure 5, the platen holding bracket 27 has a shaft 27a. One end of the shaft 27a is inserted into a boss 52a provided on the peeling unit release lever 52, and the other end of the shaft 27a is inserted into a boss provided on an internal frame (not shown). As a result, the platen holding bracket 27 is configured to swing around the shaft 27a. Although not visible in Figure 5, the lever 52 for opening the peeling unit has an inwardly protruding engaging projection 523 (see Figure 4). As will be described later, the engaging projection 523 engages with the peeling roller cover 41 of the peeling unit 4.

[0037] A hole 27c is formed in the side wall of the platen retaining bracket 27, and the projection 51c of the cover release lever 51 is inserted into the hole 27c. Here, the hole 27c is formed to be larger than the projection 51c when viewed from the side (i.e., there is play in the hole 27c), so the platen retaining bracket 27 can swing. The platen retaining bracket 27 swings around the shaft 27a, and the cover release lever 51 swings around the shaft portion 56 (see Figure 4), so the axes of oscillation are different for the two. Therefore, by providing play in the hole 27c, the difference in the trajectories of the hole 27c and the projection 51c due to the difference in the axes of oscillation is absorbed.

[0038] The peeling unit release lever 52 is configured to rotate (or swing) around a shaft 27a inserted into the boss 52a. That is, since the platen holding bracket 27 and the peeling unit release lever 52 share a single swing axis, shaft 27a, there is no need to provide a separate swing axis for the peeling unit release lever 52, which contributes to space saving and low cost. However, this is not limited to this configuration, and in another embodiment, separate swing axes may be set for the platen holding bracket 27 and the peeling unit release lever 52, respectively.

[0039] A coil spring 53 (an example of a biasing member) is positioned between the peeling unit release lever 52 and the internal frame (not shown) directly below the peeling unit release button 52b. When the peeling unit release lever 52 is pressed downward (operated) against the restoring force of the coil spring 53, the peeling unit release lever 52 swings around the axis 27a (swings clockwise in Figure 4). As will be described later, the peeling unit 4 swings via the engaging projection 523 in conjunction with the swing of the peeling unit release lever 52, moving from the closed position to the open position. When the downward pressing force of the peeling unit release button 52b is released, the peeling unit release lever 52 returns to its pre-press position (oscillates) due to the restoring force of the coil spring 53.

[0040] The platen retaining bracket 27 is biased by a pair of coil springs 29. In Figure 5, one end of each coil spring 29 is connected to the platen retaining bracket 27, and the other end of each coil spring 29 is connected to an internal frame (not shown). When no external force is applied to the platen retaining bracket 27, the platen retaining bracket 27 is in the position shown in Figure 4 when the printer cover is closed, and holds the platen shaft 10a in the groove 27b. This position is the locking position that locks the printer cover 3, to which the platen shaft 10a is connected, into the closed position.

[0041] When the cover release button 51b is pressed (operated), the cover release lever 51 swings around the shaft 56 (swings counterclockwise in Figure 4). As the cover release lever 51 swings, the projection 51c presses against the periphery of the hole 27c in the platen retaining bracket 27, causing the platen retaining bracket 27 to swing around the shaft 27a (clockwise in Figure 4) against the restoring force of the coil spring 29. As described above, the printer cover 3 to which the platen shaft 10a is attached is biased from the closed position to the open position. Therefore, when the platen shaft 10a disengages from the groove 27b due to the swinging of the platen retaining bracket 27, it moves to the open position. At this time, the position of the platen retaining bracket 27 is the unlocked position, which releases the lock in the closed position of the printer cover 3.

[0042] Conversely, when closing the printer cover 3, the pressing force applied by the operator closing the printer cover 3 causes the platen shaft 10a attached to the printer cover 3 to press against the inclined top of the platen retaining bracket 27, against the restoring force of the coil spring 29. This causes the platen retaining bracket 27 to swing clockwise as shown in Figure 4, and the platen shaft 10a is inserted into the groove 27b of the platen retaining bracket 27. With the platen shaft 10a inserted into the groove 27b, the platen retaining bracket 27 returns to the locked position when the printer cover is closed, as shown in Figure 4, due to the restoring force of the coil spring 29.

[0043] [Peeling Unit 4] Next, the peeling unit 4 will be explained with reference to Figures 6 to 9.

[0044] Figure 6 is a perspective view of the peeling unit 4 in the open and closed positions. Note that the peeling unit 4 in the closed position in Figure 6 is shown in the continuous emission position. The open position of the peeling unit 4 is the position in which the peeling roller cover 41 is opened when the peeling unit open button 52b is operated. In other words, the open position of the peeling unit 4 corresponds to the open position of the peeling roller cover 41.

[0045] The open position of the peeling roller cover 41 is, as shown in Figure 2, a position that opens at least a part of the inside of the printer 1, in other words, at least a part of the inside of the main body case 2. For example, as shown in Figure 2, when the peeling roller cover 41 is in the open position, the coil spring 55 and the flexible cable 57 connected to the thermal head 28 (see Figure 21) inside the main body case 2 are in an open state. From another perspective, the open position of the peeling roller cover 41 can also be said to be a position that opens the thermal head 28 inside the main body case 2. From yet another perspective, the open position of the peeling roller cover 41 can also be said to be a position that allows the peeling roller cover 41 to be opened when the peeling roller holding part 42 is in a position facing the back surface of the peeling roller cover 41. As shown in Figure 6, when the peeling roller cover 41 is in the open position (open state), the peeling roller holding part 42 is in a state of protruding upward (protruding state).

[0046] The closed position of the peeling unit 4 is the position where the peeling roller cover 41 is closed. In other words, the closed position of the peeling unit 4 corresponds to the closed position of the peeling roller cover 41. The closed position of the peel roller cover 41 is the position that closes at least a part of the inside of the printer 1 that is open when it is in the open position, in other words, the position that closes at least a part of the inside of the main body case 2 that is open when it is in the open position. For example, as shown in Figure 1, when the peel roller cover 41 is in the closed position, the coil spring 55, flexible cable 57, etc. are not visible from the outside and are in a closed state. From another perspective, the closed position of the peel roller cover 41 can also be said to be the position that closes at least a part of the thermal head 28 inside the main body case 2. Furthermore, from yet another perspective, the closed position of the peel roller cover 41 can also be said to be the position that keeps the peel roller cover 41 in that position without opening when the peel roller holding part 42 is in a position facing the back surface of the peel roller cover 41. When the peel roller cover 41 is in the closed position, the position of the peel roller holding part 42 differs between continuous printing and peel printing. As shown in Figure 6, when the peeling roller cover 41 is in the closed position during continuous printing (closed state), the peeling roller holding part 42 is housed beneath the peeling roller cover 41 (housed state).

[0047] Referring to Figure 6, the peeling roller cover 41 has a pair of shafts 41a (an example of a first shaft) and is a swinging member configured to swing around the shafts 41a. The shafts 41a have a circular cross-section and are inserted into a cylindrical portion (not shown) provided in the internal frame, and are configured to be rotatable. Preferably, the cylindrical portion has an elongated hole formed in the front-to-back direction of the printer so that the shafts 41a can be slightly displaced inside, for example, in the front-to-back direction of the printer. This allows for play in the front-to-back direction of the printer when the shafts 41a are inserted into the cylindrical portion, improving the impact resistance of the printer 1 against drops, etc. Furthermore, the direction of the elongated holes formed in the cylindrical portion is not limited to the front-to-back direction of the printer, but can be set to any direction in a plane perpendicular to the left-to-right direction of the printer 1, such as the up-and-down direction of the printer 1.

[0048] The peeling roller cover 41 extends in the same direction as the platen roller 10. The peeling roller cover 41 has a front surface 411 and a back surface 412. The front surface 411 is the surface that is exposed when the peeling roller cover 41 is in the closed position. The back surface 412 has a recess formed therein so that the peeling roller holding portion 42 can be accommodated. Conversely, the front surface 411 has a shape that bulges in the center in the front-to-back direction, which is convenient when a cutter is provided in the discharge portion 20 and when cutting the backing paper. The peeling roller cover 41 has an engagement hole 415 formed near the shaft 41a. As will be described later, the engagement projection 523 of the peeling unit release lever 52 is inserted into the engagement hole 415.

[0049] A pair of U-shaped grooves 413 (an example of a contact portion) may be provided on the side of the peeling roller cover 41. The U-shaped grooves 413 contact a projection 26 (see Figure 18) formed on the internal frame when the shaft 41a is in the closed position. By contacting the projection 26, the U-shaped grooves 413 function to position the peeling unit 4 in the vertical direction. When the U-shaped grooves 413 are in contact with the projection 26, a predetermined gap is provided between the peeling unit 4 and the thermal head 28. Therefore, interference between the peeling unit 4 and the thermal head 28 can be reliably prevented. As described above, the shaft 41a of the peeling unit 4 is preferably inserted into an elongated hole formed in the cylindrical part of the internal frame in the printer's front-to-back direction, thereby providing play in the printer's front-to-back direction. At this time, the U-shaped groove 413 abuts and engages with the projection 26 (see Figure 18), preventing the peeling unit 4 (peeling roller cover 41) from wobbling in the printer's front-to-back direction due to the play of the shaft 41a inserted into the elongated hole (i.e., it functions as a positioning mechanism for the peeling unit 4 in the printer's front-to-back direction).

[0050] It is not essential to provide the U-shaped groove 413 and the protrusion 26. It is sufficient that a part of the peeling unit 4 and the internal frame can come into contact with each other while maintaining a gap between the peeling unit 4 and the thermal head 28, and the shape of the contact portion can be formed as appropriate. Alternatively, instead of such a contact structure, the vertical positioning of the peeling unit 4 can be achieved, for example, by restricting the range of motion of the shaft 41a of the peeling roller cover 41.

[0051] A peeling sensor 47 is positioned on the surface 411 of the peeling roller cover 41. The peeling sensor 47 is a light-reflecting sensor that detects the presence or absence of a peeled label during peeling and issuance. In Figure 3, the label PL peeled off by the peeling bar 12 is transported under transport control so that a portion of it on the upstream side in the transport direction stops near the peeling bar 12. The peeled label PL remains on the peeling bar 12 due to its adhesive force, and the presence or absence of this label PL is detected by the peeling sensor 47. When the operator removes the peeled label, the peeling sensor 47 detects that there is no label PL and controls the machine to issue the next label.

[0052] Referring to Figure 6, the peeling roller holding portion 42 is a member that holds the peeling roller 45. The peeling roller holding portion 42 extends in the same direction as the platen roller 10, similar to the peeling roller cover 41. The pair of shafts 42a of the peeling roller holding portion 42 are positioned inward from the pair of shafts 41a of the peeling roller cover 41, so that the width of the peeling roller holding portion 42 is narrower than the width of the peeling roller cover 41, so that it can be housed under the back surface 412 of the peeling roller cover 41.

[0053] The peeling roller holding section 42 is a pivoting member having a pair of shafts 42a (an example of a second shaft) and configured to swing around the shafts 42a. The pair of shafts 42a are pivotally supported by the peeling roller cover 41 at a position spaced apart from the shaft 41a. The peeling roller 45 is positioned at the end of an arm 421 extending from the shafts 42a. Therefore, as shown in Figure 6, when the peeling unit 4 is opened, the peeling roller 45 protrudes significantly upward with respect to the shaft 41a.

[0054] In other words, the peeling roller holder 42 is pivotable between a housed position in which the peeling roller 45 is housed under the peeling roller cover 41 (an example of the first position of the peeling roller holder) and a protruding position in which the peeling roller 45 is not covered by the peeling roller cover 41 (an example of the second position of the peeling roller holder; the open position in Figure 6). The housed position of the peeling roller holder 42 is both a position facing the back surface 412 of the peeling roller cover 41 and a position covered by the peeling roller cover 41. When housing the peeling roller holder 42, the peeling roller holder 42 is swung around the shaft 42a to the back surface 412 of the peeling roller cover 41, and then the entire peeling roller cover 41 and peeling roller holder 42 are swung around the shaft 41a. As a result, the peeling roller holder 42 is folded and compactly housed under the peeling roller cover 41.

[0055] On the other hand, when the peeling roller cover 41 is in the open position, the peeling roller holder 42 is pivotable between the housed position and the protruding position. Furthermore, as will be described later, the peeling roller holder 42 is biased by the coil spring 43 from the housed position to the protruding position, so as soon as the peeling roller cover 41 moves from the closed position to the open position, the peeling roller holder 42 moves so as to pop out from the housed position to the protruding position. This allows the operator to immediately switch from continuous firing to peeling firing. Furthermore, when the peeling roller holding part 42 is in the protruding position, the peeling roller 45 protrudes higher, which allows the peeling roller 45 to be moved further away when setting the peeling unit 4 to the peeling and discharging position.

[0056] A pair of arms 421 extend from a pair of shafts 42a. At the tips of the pair of arms 421 are shafts 45a that rotate the peeling roller 45 and the auxiliary roller 46. The diameter of each auxiliary roller 46 is smaller than the diameter of the peeling roller 45. By providing auxiliary rollers 46 on both sides of the peeling roller 45, wide backing sheets can be smoothly discharged when peeling and issuing wide labels. In other words, if there were no auxiliary rollers 46, the wide backing sheet would move in the width direction (left and right direction), but by providing auxiliary rollers 46, stable transport of the wide backing sheet becomes possible. It should be noted that the auxiliary roller 46 is not mandatory. Even without the auxiliary roller 46, peeling can be performed as long as the peeling roller 45 is present. Each arm 421 has an outwardly protruding projection 422. As will be described later, the projection 422 is provided to engage the peeling unit 4 with the printer cover 3 during peeling and printing.

[0057] As shown in Figure 6, a pair of coil springs 43 (an example of a biasing member) are provided near the pair of shafts 42a of the peeling roller holder 42. Although not shown, one end of the coil spring 43 is connected to the peeling roller holder 42 and the other end is connected to the peeling roller cover 41, thereby biasing the peeling roller holder 42 in a direction that causes it to swing from the housed position to the protruding position. Therefore, when the peeling roller cover 41 is in the open position (i.e., when the peeling unit 4 is in the open position), the peeling roller holder 42 is always in the protruding position.

[0058] Figure 7 is a perspective view of the peeling unit 4 when it is open, from a different viewpoint than in Figure 6. When the peeling roller holder 42 is in the protruding position, a part of the arm 421 of the peeling roller holder 42 contacts the surface 411 of the peeling roller cover 41. That is, the surface 411 of the peeling roller cover 41 functions as a stopper for the peeling roller holder 42 which swings due to the coil spring 43.

[0059] Next, the operation of moving the peeling unit 4 to the open position from continuous firing will be explained with reference to Figures 8 and 9. Figures 8 and 9 are side views of the peeling unit release lever 52 and the peeling unit 4, and states S1 to S3 are sequential views of these side views in chronological order. State S1 indicates the state when the printer cover 3 is open during continuous printing, state S2 indicates the state when the button for opening the peeling unit is continuously operated, and state S3 indicates the state when the button for opening the peeling unit is released.

[0060] The peeling unit release lever 52 and the peeling unit 4 are engaged when the engaging projection 523 of the peeling unit release lever 52 is inserted from the inside into the engaging hole 415 of the peeling roller cover 41. The peeling unit release lever 52 swings to move the peeling roller cover 41 between the closed position and the open position. The engagement hole 415 is, for example, heart-shaped, and the engagement projection 523 is movable within the engagement hole 415. As shown in state S1 in Figure 8, when the printer cover 3 is opened during continuous printing, the engaging projection 523 is located below the engaging hole 415. At this time, the peeling roller holding part 42 is in a housed position below the back surface 412 (see Figure 6) of the peeling roller cover 41.

[0061] When the peeling unit release button 52b is pressed (operated), the peeling unit release lever 52 swings clockwise around the shaft 27a in Figure 8. As a result, the engaging projection 523 of the peeling unit release lever 52 moves upward within the engaging hole 415 and presses the peeling roller cover 41 upward at the upper edge of the engaging hole 415. As a result, the peeling roller cover 41 swings counterclockwise around the shaft 41a in Figure 8 toward the open position. As mentioned above, the peeling roller holding part 42 is biased by the coil spring 43 (see Figure 6) in the swinging direction from the housed position toward the protruding position. Therefore, when the peeling roller cover 41 swings toward the open position, the position restriction of the peeling roller holding part 42 by the second stopper 522 (described later) is released, and a space is created in which the peeling roller holding part 42 can swing, so the peeling roller holding part 42 swings to the protruding position as shown in state S2 in Figure 8.

[0062] As shown in state S2 of Figure 8, when the peel roller cover 41 is in the open position, the shaft 42a is at a higher position than when it is in the closed position. Also, as described above, when the peel roller cover 41 is in the open position, the printer 1 has a space that allows the peel roller holding part 42 to swing from the housed position to the protruding position. Therefore, the biasing force of the coil spring 43 can cause the peel roller holding part 42 to protrude upward with force.

[0063] When the release button 52b for releasing the peeling unit is released from the state shown in state S2, the restoring force of the coil spring 53 causes the peeling unit release lever 52 to swing counterclockwise around the axis 27a in Figure 8. As a result, the peeling unit release lever 52 and the peeling roller cover 41 return to the position of state S1. However, the peeling roller holding part 42, which has swung to the protruding position, does not return to the retracted position but remains in the protruding position. Consequently, the peeling unit 4 takes on the form shown in state S3 in Figure 9.

[0064] [Engagement between the release unit 4 and the printer cover 3] In printer 1, when the printer cover 3 is in state S3 as shown in Figure 9, the printer cover 3 is swung from the open position to the closed position, which allows the printer cover 3 and the peeling unit 4 to engage and set the peeling unit 4 to the peeling and issuing position. Therefore, the engagement between the peeling unit 4 and the printer cover 3 during peeling and printing will be explained below with reference to Figures 10 and 11. First, the structure of the printer cover 3 for engaging with the peeling unit 4 will be explained with reference to Figure 10. Figure 10A is a plan view of the printer cover 3, and Figure 10B is an enlarged cross-sectional view AA of Figure 10A.

[0065] As shown in Figure 10A, the printer cover 3 has a pair of peeling unit receiving sections 31 at its front end. The peeling unit receiving sections 31 are located near the positions where the platen roller 10 and the peeling bar 12 are supported. As shown in Figure 10B, the peeling unit receiving section 31 has a guide groove 31p that is open at the front. The guide groove 31p is a groove that is open only on the inside, along the direction from the front end to the rear end of the printer cover 3. The guide groove 31p receives the projection 422 (see Figure 9) of the peeling unit 4, which is located at the front during the process of closing the printer cover 3.

[0066] A roller pressing mechanism 37 is provided within the guide groove 31p. As will be described later, the roller pressing mechanism 37 presses the release roller 45 toward the platen roller 10 when the printer cover 3 is in the closed position, thereby generating the nip pressure when the backing paper is clamped between the release roller 45 and the platen roller 10. The roller pressing mechanism 37 includes a contact portion 32 positioned within the guide groove 31p and a coil spring 33 (an example of a biasing member) positioned behind the contact portion 32. As the printer cover 3 moves to the closed position, the projection 422 of the peeling unit 4 is guided to the contact portion 32.

[0067] When the printer cover 3 is moved from the open position to the closed position in state S3 of Figure 9, the projection 422 of the peeling unit 4 enters the guide groove 31p of the peeling unit receiving section 31 during the movement of the printer cover 3. As the printer cover 3 swings to the closed position, the projection 422 moves along the guide groove 31p toward the rear of the printer cover 3 and comes into contact with the contact section 32. In this way, the printer cover 3 engages with the peeling unit 4. When the printer cover 3 reaches the closed position, the peeling roller 45 of the peeling unit 4, which is engaged with the printer cover 3, is in a position facing the platen roller 10. Therefore, the operator can engage the printer cover 3 with the peeling unit 4 and move the peeling unit 4 to the peeling and issuing position simply by closing the printer cover 3.

[0068] Figure 11 is an enlarged cross-sectional view showing the vicinity of the platen roller 10 when the printer cover 3 is fully closed and the peeling unit 4 is set in the peeling and issuing position. As shown in Figure 11, when the printer cover 3 is in the closed position, the peeling roller 45 of the peeling unit 4 is positioned opposite the platen roller 10. The projection 422 of the peeling unit 4 contacts the contact portion 32 of the peeling unit receiving portion 31 of the printer cover 3, and the coil spring 33 behind the contact portion 32 is compressed. The restoring force of the coil spring 33 acts on the peeling roller 45 through the projection 422, so that the peeling roller 45 is pressed against the platen roller 10, thereby generating the nip pressure when the backing paper is held. In this way, the rotational force around the axis 42a of the peeling roller holding portion 42 (F5c in Figure 11) is replaced by the nip pressure between the peeling roller 45 and the platen roller 10.

[0069] In one embodiment, as shown in Figure 11, when viewed from the side, the direction normal to the contact surface of the contact portion 32 with which the projection 422 abuts (the direction indicated by F5b) and the direction from the center of the peeling roller 45 toward the center of the platen roller 10 may be the same, but the direction of the force F5 changes depending on the angle at which the projection 422 and the contact portion 32 abut, so it is not limited to being the same. As shown in Figure 11, the component force F5b of the reaction force F5 of the contact portion 32 acting on the projection 422, which is the component normal to the contact surface, presses the peeling roller 45 against the platen roller 10, thereby more effectively generating nip pressure when clamping the backing paper.

[0070] [Operation to house the peeling roller holding section 42] Next, referring to Figures 12 and 13, the operation of setting the peeling unit 4 to the continuous firing position by housing the peeling roller holding part 42, which is in a protruding position, under the peeling roller cover 41 will be described. To switch from peel-and-print to continuous printing, press the cover release button 51b to open the printer cover 3, and then press the peel-and-print unit release button 52b. As shown in state S2 of Figure 8, the peel-and-print roller cover 41 will swing to the open position, and the peel-and-print roller holder 42 will swing to the protruding position. In this state, the operator can fold the peel-and-print roller holder 42 and store it under the peel-and-print roller cover 41 (folding operation), thereby setting the peel-and-print unit 4 to the continuous printing position.

[0071] The states S5 to S9 in Figures 12 and 13 are perspective views showing the release lever 52 for the peeling unit and the peeling unit 4 in chronological order when the operator performs the folding operation of the peeling unit 4. As shown in Figure 12, the peeling unit release lever 52 has a first stopper 521 (an example of a first restricting part) and a second stopper 522 (an example of a second restricting part) that protrude inward. The first stopper 521 and the second stopper 522 are positioned spaced apart front to back and are provided to restrict the swinging of the arm 421 of the peeling roller holding part 42 by contacting the arm 421.

[0072] State S5 in Figure 12 is the same as state S2 in Figure 8, where the peeling roller cover 41 is in the open position and the peeling roller holding part 42 is in the protruding position. This state is maintained by the operator continuously pressing the peeling unit open button 52b.

[0073] When the operator rotates (or swings) the peel roller holder 42 around the shaft 42a in state S5, moving it to the housing position below the back surface 412 of the peel roller cover 41, the state becomes S6. At this time, the operating force causes the part of the arm 421 furthest from the shaft 42a to move over the first stopper 521. As a result, the arm 421 comes into contact with the first stopper 521, restricting the swing of the peel roller holder 42 against the restoring force of the coil spring 43 (see Figure 6). In other words, the first stopper 521 restricts the swing of the peel roller holder 42 by coming into contact with the arm 421 when the peel roller holder 42 is in the housing position and the peel roller cover 41 is in the open position. The first stopper 521 restricts the swinging of the peeling roller holder 42, making it easier to move the peeling roller cover 41 to the closed position while keeping the peeling roller holder 42 in the housing position. If the first stopper 521 were not present, the operator would need to hold the peeling roller holder 42 in place with their hand to prevent it from swinging from the housing position, while releasing the button 52b for releasing the peeling unit to move the peeling roller cover 41 to the closed position. In other words, the provision of the first stopper 521 improves operability.

[0074] With the peeling roller holding section 42 locked in the housing position by the first stopper 521, when the operator releases the button 52b for releasing the peeling unit, the peeling roller cover 41 begins to move toward the closed position. State S7 shows the state in which the peeling roller cover 41 is in the process of moving toward the closed position. As the peeling roller cover 41 moves toward the closed position, the swinging of the peeling roller cover 41 releases the swinging restriction of the arm 421 by the first stopper 521. In other words, the outer edge of the arm 421 is formed such that the swinging restriction of the arm 421 is released when the peeling roller cover 41 is closed to a predetermined angle.

[0075] State S8 in Figure 13 is the state after the operator has further closed the peeling roller cover 41 from state S7. The peeling roller holder 42, whose oscillation restriction by the first stopper 521 has been released, oscillates due to the restoring force of the coil spring 43, but its oscillation is restricted again by the second stopper 522, which is located behind the first stopper 521. In other words, the second stopper 522 contacts the arm 421 as the peeling roller holder 42 moves from the open position to the closed position, thereby restricting the oscillation of the peeling roller holder 42 at a position between the housed position and the protruding position. State S9 is the state in which the peeling roller cover 41 is in the closed position and the peeling unit 4 is in the continuous emission position. By providing the second stopper 522, it is possible to prevent the peeling roller holder 42 from swinging while the peeling roller cover 41 moves from the open position to the closed position. Furthermore, since the second stopper 522 is located behind the first stopper 521, as shown in state S9, when the peeling unit release button 52b is operated while the peeling unit 4 is in the continuous discharge position, the peeling roller holder 42 can be smoothly swung to the protruding position.

[0076] It should be noted that providing the first stopper 521 and the second stopper 522 is not necessarily required. Providing even just one of the stoppers will contribute to improved operability. Even if neither the first stopper 521 nor the second stopper 522 is provided, it is still possible to fold the peeling unit 4. That is, by having the operator hold the peeling roller holder 42 in the hoisted position by hand while carefully moving the peeling roller cover 41 to the closed position, it is possible to house the peeling roller holder 42 under the peeling roller cover 41.

[0077] [Switching operation between continuous printing and peel-off printing on printer 1] Next, the switching operation between continuous printing and peel-off printing of printer 1 will be explained with reference to Figures 14 and 15. Figures 14 and 15, showing states S10 to S15, sequentially display side views of the main parts of printer 1 when switching from continuous printing to peel-off printing. Note that the platen holding bracket 27 is omitted from the illustration in Figure 15.

[0078] State S10 in Figure 14 shows the state of printer 1 during continuous printing. In this state, the printer cover 3 is held in place by the platen shaft 10a of the platen roller 10, which is pivotally supported by the printer cover 3, fitting into the groove 27b of the platen holding bracket 27. In state S10, the peeling unit 4 is set in the continuous printing position.

[0079] In state S10, when the operator presses the cover release button 51b, the platen shaft 10a is released from the platen holding bracket 27, and as shown in state S11, the printer cover 3 moves toward the open position due to the biasing force of the torsion spring provided on the hinge 8 (see Figure 2). Next, when the operator presses the peeling unit release button 52b, as shown in state S12, the peeling roller cover 41 swings from the closed position to the open position, and the peeling roller holding part 42 swings from the housed position to the protruding position. After that, when the operator releases the peeling unit release button 52b, as shown in state S13 in Figure 15, the peeling roller cover 41 returns to the closed position, but the peeling roller holding part 42 remains in the protruding position due to the biasing force of the coil spring 43 (see Figure 6).

[0080] Next, when the operator closes the printer cover 3, the projection 422 of the peeling roller holding part 42, which is in a protruding position, is inserted into the guide groove 31p (see Figure 10) of the printer cover 3 and guided along the guide groove 31p, so that the printer cover 3 and the peeling unit 4 engage as shown in state S14.

[0081] As shown in state S15, when the printer cover 3 is in the closed position, the platen shaft 10a of the platen roller 10 is held by the platen holding bracket 27, and the peeling unit 4 is set in the peeling and issuing position. That is, the peeling roller 45 of the peeling unit 4 is positioned opposite the platen roller 10, and together with the platen roller 10, it grips the backing paper PM. In this state, as described above, the projection 422 engaged with the printer cover 3 is pressed by the coil spring 33 (see Figure 11), which generates an appropriate nip pressure on the platen roller 10 from the peeling roller 45. In peel-and-release, the label PL printed by the thermal head 28 is peeled off the backing paper PM by the peel-and-release bar 12, which causes the backing paper PM to rotate sharply. The peel-and-release roller 45 rotates in response to the rotation of the platen roller 10 and discharges the backing paper PM.

[0082] To switch from peel-and-print to continuous printing, press the cover release button 51b to open the printer cover 3, and then press the peel-and-print unit release button 52b. This causes the peel-and-print roller cover 41 of the peel-and-print unit 4 to swing to the open position, and the peel-and-print roller holding part 42 to swing to the protruding position. Then, as explained with reference to Figures 12 and 13, the peel-and-print unit 4 is folded to set it in the continuous printing position.

[0083] As described above, the printer 1 according to one embodiment includes a peeling unit 4 that is movable between a continuous printing position and a peeling printing position, and when the peeling unit 4 is in the continuous printing position, the peeling roller holding part 42 that holds the peeling roller 45 can be compactly housed in a housing position below the back surface of the peeling roller cover 41. When switching from continuous printing to peel-off printing, the printer cover 3 is opened, the peel-off unit release button 52b is operated to move the peel-off roller holder 42 to the protruding position, and the printer cover 3 is closed. In other words, the switch can be made in three simple steps, making it easy to operate. Moreover, when the printer cover 3 is in the closed position, the roller pressing mechanism 37 of the printer cover 3 presses the peel-off roller 45 against the platen roller 10, generating appropriate nip pressure. Conversely, when switching from peel-and-print to continuous printing, the printer cover 3 is opened, the peel-and-print unit release button 52b is operated to move the peel-and-print roller holder 42 to the protruding position, the peel-and-print roller holder 42 is folded back into the retracted position, and the printer cover 3 is closed. This operation is also simple.

[0084] [How to attach and detach the Thermal Head 28] Next, the method for attaching and detaching the thermal head 28 of printer 1 from printer 1 will be explained with reference to Figures 16 to 19. Figure 16A shows the front side (an example of the first side) of the thermal head 28, which is biased by the coil spring 55, and Figure 16B shows the rear side (an example of the second side) of the thermal head 28. The rear side of the thermal head 28 faces the platen roller 10. Figure 17 is an enlarged cross-sectional view showing cross-sections AA and BB of Figure 16A.

[0085] As shown in Figures 16 and 17, the thermal head 28 has a structure in which a substrate 282 is attached to a heat sink 281 (an example of a base) which is substantially rectangular in plan view. The heat sink 281 is made of a metal material with high thermal conductivity, such as aluminum. As can be seen in the AA cross section of Figure 17, the substrate 282 (an example of a coating layer) is attached to the heat sink 281 so as to extend from the surface 281a of the heat sink 281 through a first end portion 281e1 interposed between the surface 281a and the back surface 281b on the opposite side, to the back surface 281b. The substrate 282 is, for example, a ceramic substrate. The area occupied by the substrate 282 on the heat sink 281 is an example of the covering area. The front surface 281a (the side facing the rear of the printer 1) is an example of the first surface, and the back surface 281b (the side facing the front of the printer 1) is an example of the second surface. As shown in the BB cross section of Figures 16B and 17, a notch 283c (an example of an opening and an uncovered area) is provided at the substantially central position in the longitudinal direction (lateral direction) of the surface 281a of the thermal head 28. The substrate 282 is not formed in the notch 283c, and the surface 281a of the heat sink 281 is exposed. As will be described later, a protrusion 211 (see Figure 19) for allowing the thermal head 28 to swing is in contact with the notch 283c.

[0086] As shown in the AA cross-section of Figures 16A and 17, surface-mount components (SMDs) such as a connector 285, an EEPROM 286 (an example of a memory chip), and a diode 287 are mounted on the substrate 282 attached to the back surface 281b of the heat sink 281, although these are not limited to the substrate 282. When the thermal head 28 is mounted on the printer 1, a flexible cable 57 is connected to the connector 285. The flexible cable 57 transmits signals from the circuit board of the printer 1 (not shown) to the thermal head 28. When the thermal head 28 is attached to the printer 1, the relatively tall surface-mount components (connector 285, EEPROM 286, diode 287, etc. in Figure 16A) mounted on the back surface 281b of the heat sink 281 face forward of the printer 1, thus protecting these surface-mount components from moisture that may enter from the exhaust port 20 located behind the thermal head 28. On the rear side of the thermal head 28 facing the exhaust port 20 (the side with the surface 281a of the heat sink 281), a driver IC (not shown) is mounted near the heat-generating part 284. However, since the driver IC is short, the driver IC and its wiring are protected by a protective layer or coating layer along with the heat-generating part 284, so there is no problem even if moisture enters from the exhaust port 20 and adheres to it.

[0087] As shown in Figure 16B, since there are no tall surface-mount components such as connectors on the rear side of the thermal head 28 (the side where the heating element 284 is located), the transport angle of the label PL relative to the heating element 284 can be reduced (i.e., the angle can be made nearly vertical when viewed from the side) (see Figure 3). For the following reasons, print quality can be improved. The heating element 284 generally has a convex shape because it includes a glaze layer (partial glaze) that is typically convex. If a tall surface mount component is placed behind the thermal head 28, the transport angle of the label PL relative to the heating element 284 becomes large in order to avoid the surface mount component. In that case, due to the rigidity (stiffness) of the convex heating element 284 and the label PL, the label PL tends to float away from the heating element 284 at its position, making it difficult to apply the optimal printing pressure to the label PL between the heating element 284 and the platen roller 10. On the other hand, if the transport angle of the label PL relative to the heating element 284 is small, even if the heating element 284 is convex, the heating element 284 can grip the label PL with appropriate printing pressure between the heating element 284 and the platen roller 10 near the top of the heating element 284, thus improving print quality.

[0088] A pair of shafts 28a extending outward are connected to both ends of the heat sink 281. As will be described later, the pair of shafts 28a are provided for attaching the thermal head 28 to the internal frame of the printer 1. As shown in Figures 16A and 16B, the shafts 28a have a high strength configuration because they include a large-diameter portion connected to the heat sink 281 and a small-diameter portion extending outward from the large-diameter portion. The small-diameter portion of the shafts 28a is inserted into a bearing groove 25, which will be described later.

[0089] Figure 18 shows a partial cross-section of the printer 1 in a plane perpendicular to the left-right direction, with the peeling roller cover 41 in the open position and the peeling roller holding part 42 in the protruding position, achieved by continuously pressing the peeling unit release button 52b. In Figure 17, the thermal head 28 and coil spring 55 are not shown so that the bearing groove 25 into which the shaft 28a of the thermal head 28 is inserted is clearly visible. As shown in Figure 18, a substantially L-shaped bearing groove 25 is formed in the internal frame of the printer 1. Although Figure 18 only shows the bearing groove 25 that receives one of the pair of shafts 28a of the thermal head 28, a similar bearing groove 25 is formed for the other shaft 28a.

[0090] As shown in an enlarged view in Figure 18, the bearing groove 25 has a first groove 251 and a second groove 252. Here, positions P1 and P2 hypothetically represent the positions that the shaft 28a can take within the bearing groove 25. In this disclosure, when the shaft 28a is at positions P1 and P2, it may be said that the thermal head 28 is at positions P1 and P2, respectively.

[0091] The first groove 251 extends from position P1 (an example of the first position of the print head) in the direction for attaching and detaching the thermal head 28. The second groove 252 extends from position P1 to position P2 (an example of the second position of the print head) in the direction in which the coil spring 55 located in front of the thermal head 28 biases the thermal head 28 (i.e., the rearward direction; an example of the first direction). By making the bearing groove 25 an L-shaped groove consisting of the first groove 251 and the second groove 252, it is possible to switch between a position where the thermal head 28 cannot be removed by moving it upward (position P2) and a position where the thermal head 28 can be removed by moving it upward (position P1) with a relatively simple shape.

[0092] Furthermore, the thermal head 28 is displaceable between position P1 and position P2 in the direction in which the coil spring 55 biases the thermal head 28. Therefore, when installing the thermal head 28, if the shaft 28a is inserted along the first groove 251 to position P1, it can be easily set to position P2 by the biasing force of the coil spring 55.

[0093] Next, with reference to Figure 19, the method for replacing the thermal head 28 will be explained. Figure 19 is a diagram illustrating the method for replacing the thermal head 28, and shows a partial side view of the thermal head 28 in the state S20 and S21 that is to be replaced. First, when the thermal head 28 to be replaced is attached to the printer 1, it is positioned at position P2 of the bearing groove 25, as shown in state S20. In this state, the entire thermal head 28 is biased toward the platen roller 10 (not shown in Figure 19) (i.e., toward the rear) by the biasing force of the coil spring 55, thereby stably positioning the shaft 28a of the thermal head 28 at position P2.

[0094] To remove the thermal head 28 to be replaced, as shown in state S21, the thermal head 28 to be replaced is moved from position P2 to position P1 in the opposite direction to the first direction (i.e., the direction in which the coil spring 55 biases the thermal head 28) (forward), against the biasing force of the coil spring 55. Next, the thermal head 28 to be replaced is moved upward from position P1 (an example of the second direction), thereby disengaging the shaft 28a of the thermal head 28 from the bearing groove 25 and removing the thermal head 28. At this point, the flexible cable 57 is connected to the connector 285 of the thermal head 28 to be replaced (see Figure 21B), so the flexible cable 57 is disconnected from the connector 285 of the thermal head 28 to be replaced. After disconnecting the thermal head 28 to be replaced from the flexible cable 57, install the new thermal head 28 into printer 1 by following the reverse procedure of removal. Specifically, first, the separated flexible cable 57 is connected to the connector 285 of the new thermal head 28 (see Figure 16A). Then, when the operation to insert the new thermal head 28 into position P1 is performed, the biasing force of the coil spring 55 moves the thermal head 28 from position P1 to position P2. In other words, the new thermal head 28 is moved downward (an example of a direction opposite to the second direction) and the shaft 28a of the new thermal head 28 is inserted into the bearing groove 25 from the first groove 251 (see Figure 18). At this time, the tip of the coil spring 55 (one rear end of the coil spring 55) is pushed forward (in the direction against the biasing force of the coil spring 55) on the back surface 281b of the new thermal head 28 (the surface facing the front of the printer 1) while inserting it. When the shaft 28a of the new thermal head 28 reaches position P1, the biasing force of the coil spring 55 allows the shaft 28a to be moved to position P2 without requiring any operating force. As explained above, the thermal head 28 is replaced.

[0095] As shown in Figure 16B, since there are no surface-mount components such as connectors on the rear side of the thermal head 28 (the side where the heating element 284 is located), there is an advantage in that the thermal head 28 can be easily replaced. Combined with the fact that the thermal head 28 is biased to the rear by the coil spring 55, if the rear side of the thermal head 28 were not flat, the thermal head 28 would interfere with the rear internal frame (for example, the wall surface 21, etc.; see Figure 20), making it difficult to smoothly insert the thermal head 28 into the bearing groove 25. In contrast, because the rear side of the thermal head 28 is flat, a new thermal head 28 can be smoothly inserted into the bearing groove 25 while the biasing force of the coil spring 55 is at work.

[0096] The thermal head 28 is attached and detached when the peeling unit 4 is in the open position. That is, when the peeling unit 4 is in the closed position, it is in a position that covers at least a part of the thermal head 28, whereas when the peeling unit 4 is in the open position, it is in a position that does not cover the thermal head 28, as shown in Figure 2. The thermal head 28 is attached and detached when the peeling unit 4 is in the open position. When the peeling unit 4 is in the closed position, there are no other components between the peeling unit 4 and the thermal head 28, and the peeling unit 4 directly covers at least a portion of the thermal head 28.

[0097] Referring again to Figure 18, when the peeling roller cover 41 is in the open position (i.e., the peeling unit 4 is in the open position), a space is formed that allows the thermal head 28, whose shaft 28a is located at position P1, to be attached and detached. Therefore, when the operator removes the thermal head 28 from the printer 1, they simply need to open the printer cover 3, press and hold the peeling unit release button 52b to put the peeling unit 4 in the state shown in Figure 18, and then, as described above, slide the shaft 28a of the thermal head 28 from position P2 to position P1 against the biasing force of the coil spring 55, and then pull the thermal head 28 upwards to remove it. Furthermore, as shown in Figure 2, in the printer 1 of this embodiment, at least a portion of the rear side of the thermal head 28 is exposed to the roll paper storage chamber 9. Therefore, by temporarily removing the roll paper R, workspace can be secured when removing the thermal head 28, and the thermal head 28 can be removed more easily. In other words, when sliding the shaft 28a of the thermal head 28 from position P2 to position P1, the operator needs to apply force to the thermal head 28 from rear to front, but because there is space behind the thermal head 28, it is easy to apply force. Also, when the operator pulls the thermal head 28 upward, because there is space behind the thermal head 28, it is easy to put a hand into that space and pull it out.

[0098] When attaching the thermal head 28 to the printer 1, the operation is the reverse of the operation when removing the thermal head 28 from the printer 1. Similarly, with the peeling unit 4 in the state shown in Figure 18, the tip of the coil spring 55 (one rear end of the coil spring 55) is pushed forward (in the direction against the biasing force of the coil spring 55) on the back surface 281b of the thermal head 28 (the surface facing forward of the printer 1), and the shaft 28a of the thermal head 28 is inserted into the first groove 251 of the bearing groove 25 at position P1, thereby moving the thermal head 28 to position P2 due to the biasing force of the coil spring 55. Therefore, the thermal head 28 can be easily replaced without tools.

[0099] In another embodiment, the bearing groove may not be L-shaped but in a different form. The bearing groove only needs to allow the thermal head 28 to be attached and detached from position P1, for example, so it may have a groove that extends diagonally forward or diagonally backward from position P1. Alternatively, although it may be slightly more difficult to attach and detach, the bearing groove may be designed so that the groove path between position P1 and position P2 is U-shaped, starting from position P1 in Figure 18, moving forward, slightly downward, and then backward to position P2. In this case, the operator can remove the shaft 28a of the thermal head 28 by moving the shaft 28a of the thermal head 28 from position P2 to position P1 along the U-shaped groove.

[0100] [Support structure of thermal head 28] Next, the support structure of the thermal head 28 will be described with reference to Figures 20 and 21. First, the structure of the internal frame at the rear of the thermal head 28 will be explained with reference to Figure 20. Figure 20 is a perspective view showing a part of the internal frame along with the components attached to the internal frame, and a portion of it is shown in an enlarged view. Note that the thermal head 28 is not shown in Figure 20.

[0101] As shown in Figure 20, the internal frame has a wall surface 21 facing the rear surface of the thermal head 28 at the rear of the area where the thermal head 28 is located (towards the roll paper storage chamber 9). A protrusion 211 is formed on the wall surface 21. The protrusion 211 (an example of a contact portion) contacts the rear surface of the thermal head 28 when the thermal head 28 is mounted. As shown in Figure 20, preferably, the contact surface of the protrusion 211 is curved so as to be convex toward the rear surface of the thermal head 28.

[0102] Figures 21A and 21B both illustrate the forces acting on the thermal head 28 in the printer 1 of the embodiment. Figure 21A shows a cross-section in a plane perpendicular to the vertical direction, and Figure 21B shows a cross-section in a plane perpendicular to the horizontal direction. Note that Figures 21A and 21B are on different scales. As shown in Figure 21A, the protrusion 211 is positioned to contact substantially the center of the thermal head 28 in the left-right direction when the thermal head 28 is mounted. The protrusion 211 is also positioned on the rear side of the thermal head 28 to contact substantially the center of the pair of coil springs 55 in the left-right direction.

[0103] As mentioned above, a notch 283c (see Figure 16B) is provided approximately in the center of the thermal head 28 in the left-right direction, and the protrusion 211 contacts the thermal head 28 at the notch 283c. The notch 283c is not covered by the substrate 282, and the heat sink 281 of the thermal head 28 is exposed in this area, so the thermal head 28 can be supported more stably. It should be noted that providing the notch 283c is not mandatory. The protrusion 211 may support the thermal head 28 in the region of the substrate 282 without providing the notch 283c.

[0104] Preferably, the rear surface of the thermal head 28 is provided with a recess that corresponds to the shape of the protrusion 211 at a position where it contacts the protrusion 211. This makes it less likely for the position where the thermal head contacts the protrusion 211 to shift, and allows the thermal head 28 to be supported more stably. In one embodiment, a recess may be provided in the wall surface 21 of the internal frame, and a protrusion corresponding to the recess in the wall surface 21 may be provided on the rear surface of the thermal head 28. Even in this case, the thermal head 28 can be swingable while being stably supported. The shape of the protrusion 211 shown in Figure 20 is merely an example, and other forms can be adopted as long as they allow the thermal head 28 to pivotably support it. For example, instead of the shape shown in Figure 20, the outer shape of the protrusion 211 may be part of a sphere.

[0105] As shown in Figure 21A, when the printer 1 is viewed from above, a restoring force F1, F2 acts on the front of the thermal head 28 due to a pair of coil springs 55 acting backward, and a reaction force F3 acts from a protrusion 211 that abuts the rear of the thermal head 28. Here, since the protrusion 211 is located approximately in the center when the printer 1 is viewed from above, the thermal head 28 is configured to swing clockwise and counterclockwise around the protrusion 211 as a pivot point, as shown in Figure 21A.

[0106] As shown in Figure 21B, when the printer 1 is viewed from the side, a restoring force F1, F2 (F2 is not visible in Figure 21B) acts on the front of the thermal head 28 due to a pair of coil springs 55 acting backward. Above the point of application of the restoring forces F1, F2, a reaction force F4 from the platen roller 10 acts on the rear of the thermal head 28, and below the point of application of the restoring forces F1, F2, a reaction force F3 from the protrusion 211 acts on the rear of the thermal head 28. Therefore, the thermal head 28 is configured to swing clockwise and counterclockwise around the protrusion 211 as a pivot point, as shown in Figure 21B.

[0107] Furthermore, when viewed from the side of the printer 1, the point of application of the biasing force of the coil spring 55 to the thermal head 28 is between the position where the thermal head 28 receives a reaction force from the platen roller 10 and the position where the protrusion 211 supports the rear side of the thermal head 28. Therefore, since the biasing force of the coil spring 55 is received from both above and below, the thermal head 28 can be supported in a balanced manner.

[0108] In Figure 21B, it is preferable that the surface on the rear side of the thermal head 28 that the protrusion 211 contacts (i.e., the surface where the heat sink 281 is exposed by the notch 283c) and the surface corresponding to the heat generating part 284 lie on the same reference plane. This allows the heat generating element of the thermal head 28 to be pressed against the platen roller 10 at an appropriate angle.

[0109] As shown in Figures 21A and 21B, the thermal head 28 is configured to pivot clockwise or counterclockwise when viewed from the side of the printer 1, with the protrusion 211 as the pivot point, and clockwise or counterclockwise when viewed from above the printer 1, with the protrusion 211 as the pivot point. Therefore, the thermal head 28 can apply uniform pressure to the platen roller 10 during printing. The reason for this is as follows.

[0110] In conventional printers equipped with thermal heads, the thermal head was attached to the internal frame or housing of the printer by fixing it at, for example, two points using screws, shafts, or brackets. In such cases, misalignment of the mounting position could cause the pressure exerted when the thermal head contacts the platen roller to become uneven in the axial direction of the platen roller, potentially leading to a decrease in print quality. In contrast, in this embodiment, in the side view and top view of the printer 1, the thermal head 28 can pivot around the convex portion 211 as a pivot point. Therefore, even if there is an error in the mounting of the platen roller 10, circumferential runout when the platen roller 10 rotates, or unevenness in the label temporarily attached to the backing paper, the thermal head 28 can follow along and maintain uniform pressure on the platen roller 10. Furthermore, since the thermal head 28 is displaceable between position P1 and position P2 (see Figure 18) in the direction in which the coil spring 55 biases the thermal head 28, the oscillation of the thermal head 28 with the convex portion 211 as the pivot point is not hindered.

[0111] While some conventional printers equipped with thermal heads have a pivot axis located below the thermal head and fixed to the printer body, allowing the thermal head to pivot in a side view, unlike printer 1, the thermal head could not be replaced without tools. In contrast, printer 1 is superior to conventional printers in that it allows the thermal head 28 to be replaced without tools while also allowing the printer 1 to pivot in both a side view and a top view.

[0112] In another embodiment, two protrusions 211 may be provided on the wall surface 21 shown in Figure 20, spaced apart in the left-right direction. Even in this case, the thermal head 28 can still be pivoted using the protrusions 211 as pivot points when viewed from the side of the printer 1. Even if the thermal head 28 can only be pivoted when viewed from the side of the printer 1, this can still contribute to a decrease in print quality. In another embodiment, two protrusions 211 may be provided on the wall surface 21 shown in Figure 20, spaced apart in the vertical direction. Even in this case, the thermal head 28 can still be pivoted around the protrusions 211 as pivot points in a plan view of the printer 1. Even if the thermal head 28 can only pivot in a plan view of the printer 1, this can still contribute to a decrease in print quality.

[0113] As shown in Figure 16A, a flexible cable 57 is detachably connected to the thermal head 28. As shown in Figure 21B, when the thermal head 28 is mounted on the printer 1, this flexible cable 57 is connected from the connector 285 of the thermal head 28 to a circuit board (not shown) located at the front of the printer 1. At this time, the flexible cable 57 is fixed at a fixing position 24a on the upper surface of the bracket 24, which is located in front of the thermal head 28, for example, by screws or adhesive.

[0114] A cable housing chamber 59 for accommodating a flexible cable 57 is formed between the thermal head 28 and the circuit board. The relatively long flexible cable 57 is housed in the cable housing chamber 59 between the connector of the thermal head 28 and the fixed position 24a. Therefore, when the thermal head 28 is removed, it can be moved to a position sufficiently higher than the printer 1 with respect to the fixed position 24a, and the work of removing the flexible cable 57 from the connector of the thermal head 28 and attaching it to a new thermal head 28 is made easy. It should be noted that forming the cable housing chamber 59 is not mandatory. The cable length from the connector 285 of the thermal head 28 to the fixed position 24a will be shorter, but even in that case, it is still possible to remove the flexible cable 57 from the connector 285 and replace the thermal head 28.

[0115] As shown in Figures 21A and 21B, the cable housing chamber 59 is formed in the space between the platen retaining bracket 27 and the thermal head 28. Therefore, the space formed by the U-shaped platen retaining bracket 27 in plan view can be utilized efficiently. Furthermore, the cable housing chamber 59 does not necessarily have to be formed in the space between the platen retaining bracket 27 and the thermal head 28. For example, the flexible cable 57 extending from the connector of the thermal head 28 can be routed under the platen retaining bracket 27, and the housing chamber can be provided in front of the platen retaining bracket 27.

[0116] As explained above, in the printer 1 described above, surface-mount components are not mounted on the rear surface of the thermal head 28, thus protecting the surface-mount components from moisture and other substances that may enter from the discharge section 20. In the printer 1 described above, a space is formed that allows the thermal head 28 to be attached and detached when the peeling unit 4 is in an open position that does not cover the thermal head 28, thereby improving the ease of replacing the thermal head 28. Moreover, the thermal head 28 is biased towards the rear (towards the platen roller 10), and is configured to be displaceable along this direction between a first position where the thermal head 28 can be attached and detached, and a second position where the attachment and detachment of the thermal head 28 is restricted. Therefore, to remove the thermal head 28, it is only necessary to move the thermal head 28 from the second position to the first position, and no tools are required.

[0117] In the printer 1 described above, the thermal head 28 is configured to pivot clockwise or counterclockwise when viewed from the side of the printer 1, with the protrusion 211 as the pivot point, and clockwise or counterclockwise when viewed from above the printer 1, with the protrusion 211 as the pivot point. Therefore, the thermal head 28 can apply uniform pressure to the platen roller 10 during printing, and a decrease in print quality caused by the mounting method of the thermal head can be prevented.

[0118] [Another embodiment of a thermal head] Next, with reference to Figures 22 to 25, a thermal head 28A according to another embodiment will be described. Figure 22A is a perspective view of the thermal head 28A from the front, and Figure 22B is a perspective view of the thermal head 28A from the rear. Figure 23 is a perspective view of the plate-shaped member included in the thermal head 28A. Figure 24 is a perspective view of the thermal head 28A from a different viewpoint than that shown in Figure 22.

[0119] As can be seen by comparing Figures 22A and 22B with Figures 16A and 16B, the thermal head 28A differs from the thermal head 28 in that it includes a plate-shaped member 7. The plate-shaped member 7 is a component formed from a metal material such as stainless steel and is fastened to the heat sink 281 by screws. As shown in Figure 23, the plate-shaped member 7 has a base portion 71, protruding pieces 72L and 72R, and a protruding plate 73.

[0120] The protruding pieces 72L and 72R each protrude from both ends of the base 71 in a direction perpendicular to the main surface of the base 71 (i.e., perpendicular to the surface 281a when attached to the heat sink 281). When the plate-shaped member 7 is attached to the heat sink 281, as shown in Figure 24, the protruding pieces 72L and 72R protrude on the side where the heat generating part 284 is mounted. The tips of the protruding pieces 72L and 72R have tip portions 721L and 721R. A hole 72a is formed in the protruding piece 72L, and a U-shaped groove 72b is formed in the protruding piece 72R. As shown in Figures 22A and 28B, one of the pair of shafts 28a is inserted into the hole 72a, and the other shaft 28a is inserted into the U-shaped groove 72b. Since a hole is formed in one of the tip portions 721L and 721R and a U-shaped groove is formed in the other, the plate-shaped member 7 is easily attached to the heat sink 281. When the plate-shaped member 7 is attached to the heat sink 281, as shown in Figure 22A, the protruding plate 73 protrudes on the side where relatively tall surface-mount components (e.g., connector 285, EEPROM 286, diode 287, etc.) are mounted.

[0121] The protruding plate 73 is provided between the protruding pieces 72L and 72R along the longitudinal direction of the base 71, and protrudes from the base 71 in the direction opposite to that of the protruding pieces 72L and 72R. The base portion 71 has two holes 71a for inserting screws when attaching the plate-shaped member 7 to the heat sink 281. The base portion 71 has two protrusions 711. As shown in Figure 22A, the protrusions 711 are positioned so as not to interfere with surface-mount components when the plate-shaped member 7 is attached to the heat sink 281.

[0122] The effects of the thermal head 28A equipped with the plate-shaped member 7 will be explained below with reference to Figure 25. Figure 25 is a side view showing the positional relationship between the thermal head 28A and the platen holding bracket 27.

[0123] As mentioned above, when the printer cover 3 is in the closed position, the printer cover 3 is held in place by the platen shaft 10a of the platen roller 10 attached to the printer cover 3 fitting into the groove 27b of the platen holding bracket 27. In this case, if the thermal head 28 does not have a plate-shaped member 7, when the operator presses down on the printer cover 3 from above, such as when closing the printer cover 3, the platen roller 10 shifts downward from the designed position where the platen roller 10 and the thermal head 28 make contact. This causes fluctuations in print density. The thermal head 28 is attached to a bearing groove 25 (see Figure 18) provided in the internal frame, one end of the shaft 27a of the platen holding bracket 27 is inserted into the boss 52a of the peeling unit release lever 52, and the other end of the shaft 27a is inserted into a boss provided in the internal frame (see Figure 5). Therefore, the contact point between the platen roller 10 and the thermal head 28 is susceptible to the cumulative assembly errors of each part and is prone to deviating from the design position described above.

[0124] The aforementioned problems with the thermal head 28 are resolved by the thermal head 28A. As shown in an enlarged view in Figure 25, when the thermal head 28A is installed in the printer 1 instead of the thermal head 28, the upper ends of the tip portions 721L and 721R of the plate-shaped member 7 of the thermal head 28A are positioned higher than the edge forming the groove 27b of the platen holding bracket 27. Therefore, the platen shaft 10a, which fits into the platen holding bracket 27, contacts the tip portions 721L and 721R within the groove 27b. As a result, even when the operator presses down on the printer cover 3 from above, the platen roller 10 is less likely to shift downward from the designed position where the platen roller 10 and the thermal head 28 are in contact. This is because the plate-shaped member 7 has an integrated structure with the heat sink 281 on which the heat-generating part 284 is mounted, so even if the platen shaft 10a pushes down the tip portions 721L and 721R, the relative positional relationship between the platen roller 10 and the heat-generating part 284 is less affected.

[0125] Referring again to Figure 25, when the thermal head 28A is mounted on the printer 1, the protruding plate 73 of the plate-shaped member 7 protrudes toward the front of the printer 1. As a result, the area above the cable housing chamber 59 formed in front of the thermal head 28A is covered by the protruding plate 73, preventing dust from entering the printer 1 from the outside and preventing dust from adhering to the upper surface of the surface-mount components located in front of the thermal head 28A. In other words, the protruding plate 73 functions as a canopy. In particular, as shown in Figure 2, the replacement of the roll paper R is performed with the printer cover 3 in the open position, making it easy for dust to enter the printer 1, but even then, the surface-mount components of the thermal head 28A can be protected from dust. From another perspective, providing the protruding plate 73 has the advantage of increasing the strength of the plate-like member 7.

[0126] Although embodiments of the printer of the present invention have been described above, the present invention is not limited to the above embodiments. Furthermore, the above embodiments can be improved or modified in various ways without departing from the spirit of the present invention. For example, the individual technical features described in the above embodiments can be combined as appropriate, as long as there is no technical contradiction.

[0127] For example, the structure and attachment / detachment method of the thermal heads 28 and 28A are not technically related to the structure of the peeling unit 4 or the method of switching the emission mode, and therefore may be applied to printers that do not have a peeling unit 4. Conversely, the structure and emission mode switching method of the peeling unit 4 may be applied to printers that employ a structure and attachment / detachment method different from that of the thermal heads 28 and 28A described above.

[0128] The explanation described a case where some of the internal components of printer 1 (for example, a shaft, one end of a spring, etc.) are connected to the internal frame, but this is not limited to that case; they may also be connected to the main body case 2.

[0129] The embodiments described above describe a case in which a continuous sheet of paper with multiple labels temporarily attached to a backing sheet is used as the printing medium, but the invention is not limited to this. When used for continuous printing, or in the case of a printer without a peeling unit, for example, a continuous label with an adhesive surface on one side (label without backing sheet), a continuous sheet without an adhesive surface (continuous sheet), or a film that can be printed on by a thermal head, not limited to paper, can also be used as the printing medium. Furthermore, when transporting labels without backing sheet where the adhesive is exposed, the transport path can be covered with a non-adhesive material, and a non-adhesive roller containing silicone or the like can be provided as a platen roller. [Explanation of Symbols]

[0130] 1…Printer 2…Main unit case 21…Wall surface 211... protruding part 24…Bracket 3…Printer cover 31... Peeling unit receiving section 31p... Guide groove 37... Roller pressing mechanism 32...Contact part 33... Coil spring 35...Sensor 4…Peeling unit 41... Peeling roller cover 41a...axis 411...Surface 412...Back side 413...U-shaped groove 415...Engagement hole 42... Peeling roller holding section 42a…axis 421... Arm 422…Protrusion 43... Coil spring 45... Stripping roller 45a…axis 46... Auxiliary roller 47... Peeling sensor 6a... Roll paper guide 7…Plate-shaped member 71...Base 71a…hole 711...Protrusion 72L,72R…Protruding piece 72a…hole 72b…U-shaped groove 721L,721R…Tip 73...Protruding plate 8... Hinge 81...Hinge axis 9…Roll paper storage room 10... Platen roller 10a...Platen shaft 10b...Gear 12... Peeling bar 15…Display panel 20…Discharge section 22b... Gear 25...Bearing receiving groove 251…1st groove 252…Second groove 26… protrusion 27…Platen retaining bracket 27a...axis 27b…Groove 27c…hole 28, 28A… Thermal head 28a...axis 281...Heat sink 281a…Surface 281b…Back side 282... Circuit board 283c... Notch 284…heat-generating part 285… Connector 29... Coil spring 51...Lever for opening the cover 51a... Shaft insertion hole 51b... Button for opening the cover 51c…Protrusion 52...Lever for opening the peeling unit 52a... Boss 52b... Button for opening the peeling unit 521...First Stopper 522... Second stopper 523...Engagement protrusion 53, 55... coil springs 56... Shaft 57... Flexible cable 59… Cable housing room P...Continuous paper PM...backing card PL...label R... Roll paper

Claims

1. A printer capable of peeling off a label from a backing sheet and printing a label that is detachably attached to a backing sheet of a printing medium, A transport roller for transporting the aforementioned printing medium, A print head that grips the printing medium together with the transport roller and prints information onto the label, A peeling unit that holds a peeling roller facing the transport roller when the label is peeled off and issued, and is movable between a position that covers at least a portion of the print head and a position that does not cover the print head, Equipped with, The print head has a pair of shafts extending outward from both sides, A pair of grooves is formed which extend in a predetermined direction and which allow the pair of shafts to move in the predetermined direction. When the peeling unit is positioned so as not to cover the print head, a space is formed for pulling the print head out in the predetermined direction. Printer.

2. The predetermined direction is the upward direction of the printer when the printer is placed on a horizontal surface. The printer according to claim 1.

3. The print head has a biasing member that biases it toward the transport roller, The predetermined direction extends in a direction perpendicular to the direction in which the biasing member biases the print head. The printer according to claim 1.

4. The peeling unit has a peeling roller cover and a peeling roller holding part that holds the peeling roller, If the peeling unit is positioned to cover at least a portion of the print head, the peeling roller cover covers at least a portion of the print head. The printer according to claim 1.

5. The position in which the peeling unit does not cover the print head is the position in which, when the printer is placed on a horizontal surface, the print head does not overlap with the peeling unit when viewed from above. A printer according to any one of claims 1 to 4.

6. The position in which the peeling unit does not cover the print head is the position in which the upper surface of the print head is exposed. A printer according to any one of claims 1 to 4.

7. It has a storage chamber for housing the aforementioned printing medium, At least a portion of the print head is exposed to the housing chamber. A printer according to any one of claims 1 to 4.

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