JP2021154718A - Printing unit and thermal printer - Google Patents

Abstract

To enable a platen roller to be surely locked, and yet enable the locking to be smoothly released by slight operation force and further enable a size of an outer shape to be compacted.SOLUTION: A printing unit comprises a platen lock mechanism 30 that switches between a lock state where a platen roller 45 is locked and a lock-releasing state, and an energizing member that energizes lock arms 140 and 150. A storage groove 62 that stores a platen bearing 51 through an opening port is formed in a head unit 5. The lock arms press the platen bearing when an operation lever 28 is at a lock position P3, and oscillates accompanying movements of the operation lever to allow the platen bearing to separate from the inside of the storage groove. In the rock arms are formed pressing-up arms that press up the platen bearing toward the opening port accompanying movements of the operation lever toward a lock-releasing position. The energizing member energizes the lock arms toward the platen unit.SELECTED DRAWING: Figure 5

Description

The present invention relates to a printing unit and a thermal printer.

A thermal printer in which a thermal head and a platen roller are separably combined is known.
For example, a thermal printer is known in which a head unit having a thermal head is provided on the housing side for storing roll paper, and a platen unit having a platen roller is provided on the printer cover side connected to the housing so as to be openable and closable. Has been done. According to this thermal printer, it is possible to combine the thermal head and the platen roller in a separable manner as the printer cover is opened and closed.

Usually, this type of thermal printer is often provided with a locking mechanism for holding the platen roller in order to prevent the two from separating at an unintended timing when the thermal head and the platen roller are combined. ..
As a locking mechanism, for example, a mechanism that presses bearings provided at both ends of a platen shaft by using a spring member is known. The spring member is provided in the head unit on the housing side, and when the bearing is fitted in the bearing groove, the spring member presses the bearing by using its own elastic restoring force (spring force). As a result, the bearing can be pressed against the bearing groove with a constant pressing force, and the platen roller can be locked (held).

However, in the case of the method of locking the platen roller by using the spring member, since the bearing is only pressed by the spring member, the locking of the platen roller tends to be insufficient. Therefore, for example, when an external force acts on the platen roller, the bearing may move in the direction of coming out of the bearing groove.
Therefore, the engagement between the driven gear integrally provided with the bearing and the train wheel for driving the platen roller becomes insufficient, which may cause inconvenience called tooth skipping or inconvenience that the engagement itself is released. There was sex. Furthermore, there is a possibility that the bearing may come off from the bearing groove and the head unit and the platen unit may be separated from each other. In particular, when the platen unit is provided on the printer cover, an external force is likely to act on the platen roller via the platen cover, so that the above-mentioned inconvenience is likely to occur.

As a countermeasure against the above-mentioned inconvenience, for example, it is conceivable to increase the spring force of the spring member. However, in this case, when the head unit and the platen unit are separated, it becomes difficult for the bearing to come out from the bearing groove, so that a large force is required to open the platen roller. Therefore, the operability is deteriorated.

Therefore, a thermal printer that employs a lock arm method that locks a platen roller by using a lock arm instead of a spring member is known.
For example, as shown in Patent Document 1 below, the bearing is pressed against the bearing groove via the lock arm by utilizing the spring force of the head pressure spring for pressing the thermal head against the platen roller. So, a thermal printer that locks a platen roller is known. According to this thermal printer, unlike the spring member, the lock arm is used, so that it is possible to prevent the bearing from moving so as to come out of the bearing groove.

Japanese Unexamined Patent Publication No. 2000-318260

However, even in the case of the lock arm method, since the lock arm is pressed against the bearing by using the spring force of the head pressure spring, the force required to open the platen roller is the spring force of the head pressure spring. In addition to being dependent, it tends to be more powerful than necessary. Therefore, the operability is likely to be deteriorated, and there is room for improvement.

Further, since this type of lock arm is usually configured to lock the bearing from the platen unit side, when releasing the lock, the lock arm is directed toward the platen unit side so as to be separated from the thermal head side. Will move. Therefore, it is necessary to secure a movable space in consideration of the movable stroke amount of the lock arm, and therefore it is necessary to design the platen unit to be large.
In general, the platen unit has fewer components than the head unit, so it is desirable to design it compactly by making it smaller and thinner. However, as described above, the movable space of the lock arm is secured. It is difficult to design compactly because it is necessary to do so. Therefore, securing a movable space eventually affects the size of the entire printer, which has become a design constraint.

The present invention has been made in consideration of such circumstances, and an object of the present invention is that the platen roller can be reliably locked, the lock can be smoothly released with a small operating force, and the outer shape thereof. It is an object of the present invention to provide a printing unit and a thermal head capable of reducing the size.

(1) The printing unit according to the present invention rotatably supports both ends of a head unit having a thermal head for printing on recording paper, a platen roller for feeding the recording paper, and both ends of the platen roller. A platen unit having a pair of platen bearings and separably combined with respect to the head unit, a lock position for locking the platen unit with respect to the head unit, and unlocking of the platen unit with respect to the head unit. An operating lever that can move around the rotation axis between the unlocking position and a lock arm that can swing around the swing axis parallel to the platen roller, and a locked state that locks the platen roller. The head unit is provided with a platen lock mechanism for switching between an unlocked state for releasing the lock, and an urging member for urging the lock arm around the swing axis so as to maintain the locked state. Is capable of fitting the pair of the platen bearings inside through the opening, and when the operating lever is located at the lock position, the pair of the platen bearings are accommodated in a state of being in contact with the groove bottom. A groove is formed, and the lock arm presses at least one of the pair of platen bearings housed in the housing groove from the opening side when the operating lever is located at the locking position. As the operating lever moves from the locked position toward the unlocked position side, the platen bearing swings around the swing axis and the platen bearing is detached from the accommodating groove through the opening. The platen bearing is pushed up from the groove bottom toward the opening side as the operating lever moves from the locking position to the unlocking position on the lock arm. A push-up arm is formed, and the urging member urges the lock arm toward the platen unit side.

According to the printing unit according to the present invention, when the platen unit is combined with the head unit and the operating lever is located at the locked position, the pair of platen bearings are housed in the pair of housing grooves. Then, the lock arm of the platen lock mechanism presses at least one platen bearing from the opening side of the accommodating groove. As a result, the lock arm can be used to prevent the platen bearing from coming out of the accommodating groove, and the platen roller can be maintained in the locked state. Moreover, since the lock arm is urged by the urging member so as to maintain the locked state, it is possible to prevent the lock arm from unintentionally swinging around the swing axis and the locked state being released.
In this way, the lock arm can be used to prevent the platen bearing from coming off from the accommodating groove, so that the platen roller can be reliably locked.

When separating the platen unit from the head unit, operate the operating lever from the locked position to the unlocked position. As a result, the lock arm can be swung around the swing axis against the urging force of the urging member. Therefore, the lock arm can be separated from the platen bearing, and the platen bearing can be allowed to separate from the accommodating groove. Further, the platen bearing can be pushed up from the groove bottom toward the opening side by using the push-up arm in conjunction with the movement of the lock arm. As a result, the platen roller can be switched to the unlocked state, and the head unit and the platen unit can be separated.

In particular, in conjunction with the operation of the operation lever, not only the lock arm can be retracted from the accommodating groove, but also the platen bearing can be forcibly pushed up toward the opening side by using the push-up arm. The platen roller can be separated from the accommodating groove without being affected by the urging force of the urging member. Therefore, it is not necessary to operate the operating lever with an excessive force, the lock of the platen roller can be released with a small operating force, and the head unit and the platen unit can be smoothly separated.

Furthermore, since the platen bearing is pressed by using the lock arm, one platen bearing is locked, and the other platen bearing is not locked or the lock is insufficient, so-called one-sided tightening (one-sided up) is unlikely to occur. .. Therefore, it is not necessary to add a mechanism or the like for preventing one-sided tightening, and the design can be facilitated. Further, since the lock arm and the push-up arm are integrally formed into one component, the number of components can be reduced and the configuration can be simplified.

(2) The lock arm swings around the swing axis from the platen unit side toward the head unit side as the operation lever moves from the lock position toward the unlock position side. It may be moved to allow the platen bearing to be detached from the accommodation groove through the opening.

In this case, when the platen roller is unlocked, the lock arm is swung from the platen unit side toward the head unit side unlike the conventional case, so that a movable space for moving the lock arm is secured on the platen unit side. You don't have to. Therefore, the platen unit can be made smaller and thinner by that amount, and the outer size of the entire printing unit can be made more compact.

(3) The push-up arm may be made non-contact with the platen bearing when the operating lever is located at the locked position.

In this case, the platen bearing can be held so as to be sandwiched between the groove bottom of the accommodating groove and the lock arm, and the platen bearing can be locked in a state of being more stably accommodated in the accommodating groove.

(4) An inclined guide protrusion formed on the inner surface of the accommodating groove so that the opening width is narrowed from the opening side toward the groove bottom side, and guides the platen bearing toward the groove bottom portion. The platen bearing may be pushed up by the push-up arm so that the roller center of the platen roller moves toward the opening side of the guide protrusion.

In this case, by moving the operation lever to the unlocked position side, the platen bearing is moved so that the roller center of the platen roller moves to the opening side of the push-up arm from the apex of the guide protrusion in the accommodation groove. Is greatly forcibly pushed up. As a result, the platen bearing can be pushed up to the vicinity of the opening in the accommodating groove to shift to a state in which the platen bearing is substantially detached, so that the work of separating the head unit and the platen unit can be performed more easily.

(5) The lock arms are arranged on both sides of the platen roller, and a pair of the lock arms are provided corresponding to the pair of the platen bearings. The platen lock mechanism extends along the swing axis and a pair of the above. A connecting shaft portion for connecting the lock arms may be provided.

In this case, since each of the pair of platen bearings accommodated in the pair of accommodating grooves can be pressed by using the pair of lock arms, the platen rollers can be locked more reliably. Further, since the pair of lock arms are connected to each other via the connecting shaft portion, the pair of lock arms can be swung around the swing axis in a synchronized state. Therefore, it is possible to more reliably switch between the locked state and the unlocked state of the platen roller using the pair of lock arms.

(6) A fixed blade provided on one of the head unit and the platen unit, and a movable blade provided on the other of the head unit and the platen unit and movable relative to the fixed blade. A drive rack connected to the movable blade, and a drive mechanism for moving the movable blade between a standby position away from the fixed blade and a cutting position mounted on the fixed blade. Is also good.

In this case, since the movable blade can be moved between the standby position and the cutting position by using the drive mechanism, the printed recording paper can be cut by using the fixed blade and the movable blade. , For example, it can be used as a receipt, a ticket, or the like. In particular, since the head unit and the platen unit can be combined with the platen roller securely locked, the movable blade and fixed blade can also be set in the optimum state for cutting, ensuring good cutting performance. can do.

(7) In a state where the movable blade is stopped at the cutting position, the platen lock mechanism uses the operating force associated with the operation of the operation lever from the lock position to the unlock position, and the platen lock mechanism moves the platen. A return mechanism for moving the movable blade from the cutting position to the standby position before switching the roller to the unlocked state may be provided.

In this case, a paper jam (paper jam) occurs between the fixed blade and the movable blade, and even if the movable blade stops at the cutting position due to this paper jam, the paper jam is performed by operating the operation lever. After releasing, the platen roller can be unlocked. That is, when the operation lever is operated from the lock position to the unlock position, the return mechanism uses the operating force associated with the operation of the operation lever to move the movable blade before the platen lock mechanism switches the platen roller to the unlocked state. Forcibly move from the cutting position to the standby position. As a result, the paper jam generated between the fixed blade and the movable blade can be released. Then, after moving the movable blade to the standby position, the lock arm retracts from the accommodating groove and the push-up arm pushes up the platen bearing from the accommodating groove by operating the operating lever. Therefore, the lock of the platen roller can be released after the paper jam is released, and the head unit and the platen unit can be separated from each other.
In this way, by operating the operation lever from the lock position to the unlock position, the paper jam can be released and the platen roller can be unlocked in a series of steps. It can be an easy-to-use printing unit.

(8) The return mechanism rotates in a state where the return rack formed on the drive rack, the return pinion that meshes with the rack teeth of the return rack, and the rotation axis of the operation lever are arranged coaxially. The return gear is provided with a return gear and a sun gear that are rotatably supported around the axis, a planetary gear that meshes with the sun gear and revolves with the movement of the operation lever, and an internal gear that meshes with the planetary gear. , May be able to mesh with the return pinion.

In this case, when the operation lever is operated toward the unlocked position side, the planetary gear can be revolved as the operation lever moves. At this time, since the planetary gear can be revolved while meshing with the internal gear, the planetary gear can be revolved while rotating. Therefore, the sun gear can be rotated along with the rotation of the planetary gear, and the return gear can be rotated together with the sun gear. As a result, the return pinion can be rotated with the rotation of the return gear, and the return rack can be moved with the rotation of the return pinion. As a result, the movable blade can be forcibly moved from the cutting position to the standby position side via the drive rack.

In this way, the operating force associated with the operation of the operating lever can be reliably transmitted to the drive rack via each gear, return pinion, return rack, etc., so that the movable blade can be reliably moved toward the standby position side. be able to. In particular, since the planetary gear is used, it is possible to secure a large rotational force of the return gear with respect to the operating stroke amount of the operating lever. Therefore, it is possible to secure the amount of rotation of the return gear required to return the movable blade to the standby position side while suppressing the amount of operation stroke of the operation lever to be smaller. As a result, the operability of the operation lever can be ensured satisfactorily.

(9) The rack teeth mesh with the return pinion when the movable blade is located at the cutting position, and the mesh with the return pinion is released when the movable blade is located at the standby position. As described above, it may be formed on the opposite side of the cutting edge of the movable blade.

In this case, when the movable blade is in the standby position, the mesh between the rack teeth of the return rack and the return pinion can be released, so when unlocking the platen unit using the operation lever, the return pinion Can be idled. As a result, the platen unit can be unlocked while the movable blade is securely maintained in the standby position.

(10) The lock arm has a linear detachment prevention surface for preventing the platen bearing from detaching from the accommodating groove through the opening in the locked state, and the platen from the rotation center of the lock arm. The line passing through the center of the bearing and the detachment prevention surface may intersect vertically.

In this way, due to the structure in which the line passing through the bearing center from the center of rotation and the bearing holding surface of the lock arm are at right angles, even if the platen roller is pulled away from the accommodating groove by an external force in the locked state, Since no force is generated to move the lock arm in the release direction, it is possible to prevent the platen roller from coming off.

(11) The platen bearing is provided with a platen support spring that assists the platen bearing to be held in the accommodation groove, and the platen support spring moves the operating lever from the lock position toward the unlock position side. As a result, before the push-up arm pushes up the platen bearing, the platen bearing moves in a direction of releasing the holding of the platen bearing, and the platen bearing can be allowed to be detached from the accommodating groove through the opening. May be said.

In this way, by providing the platen support spring that assists the holding of the platen roller, even if there is a gap between the release prevention surface of the lock arm and the platen bearing in the locked state, the backlash due to the gap is absorbed. Can hold platen bearings. Further, when the lock is released, the platen support spring moves in the direction of releasing the holding of the platen bearing before the push-up arm pushes up the platen bearing, so that the platen roller can be smoothly released.

(12) The thermal printer according to the present invention includes the printing unit, a recording paper storage unit for accommodating the recording paper, and a printer main body to which one of the head unit and the platen unit is attached. It is characterized by including a printer cover that is rotatably connected to the printer main body and to which the other of the head unit and the platen unit is attached.

According to the thermal printer according to the present invention, since the printing unit is provided, the printer cover can be securely closed with respect to the printer main body by using the combination of the head unit and the platen unit, and the printer cover is slightly closed. The printer cover can be opened by operating force. Therefore, operability when opening and closing the printer cover can be ensured satisfactorily. Further, the thermal printer can be made compact and easy to reduce the weight.

According to the present invention, the platen roller can be reliably locked, the lock can be smoothly released with a small operating force, and the external size can be further reduced.

It is a perspective view of the thermal printer which concerns on embodiment of this invention, and is the perspective view which shows the state which the printer cover is closed. It is a perspective view of the thermal printer in the state which the printer cover shown in FIG. 1 is open. It is a perspective view of the printing unit shown in FIG. It is a perspective view of the printing unit which shows the state which removed the gear cover and the like from the state shown in FIG. It is a perspective view of the printing unit which shows the state which removed the platen frame and the like from the state shown in FIG. It is a perspective view of the platen unit shown in FIG. It is a side view seen from the direction of arrow A shown in FIG. 5, and is the figure which shows the relationship between the accommodating groove and a platen bearing. It is a perspective view which shows the state which cuts the recording paper between a fixed blade and a movable blade. It is a side view seen from the direction of arrow A shown in FIG. It is a perspective view of each mechanism shown in FIG. It is a perspective view which looked at the periphery of the operation lever shown in FIG. 10 from the opposite side. It is a perspective view which shows the state which removed the operation lever from the state shown in FIG. It is a perspective view which shows the state which removed the operation lever from the state shown in FIG. It is a side view which shows the periphery of the other lock arm. From the state shown in FIG. 9, it is a side view which shows the state which the paper jam occurred between the movable blade and the fixed blade. It is a side view which shows the state which pushed down the operation lever from the lock position shown in FIG. It is a side view which shows the state which pushed down the operation lever further from the state shown in FIG. FIG. 6 is a side view showing a state in which the operating lever is further pushed down to be positioned at the disengagement disengagement position from the state shown in FIG. FIG. 5 is a side view showing a state in which the operating lever is further pushed down to return the movable blade to the standby position from the state shown in FIG. FIG. 19 is a side view showing a state in which the operating lever is further pushed down to be positioned at the unlocked position and the platen bearing is pushed up to the opening of the accommodating groove from the state shown in FIG. It is a figure which shows the thermal printer which concerns on other embodiment of this invention, and is the side view seen from the direction of arrow A shown in FIG. It is a side view which shows the state which removed the lock arm from the state shown in FIG. It is a perspective view of each mechanism shown in FIG. It is a perspective view which shows the state which removed the lock arm from the state shown in FIG. It is a side view which shows the periphery of the other lock arm in the thermal printer which concerns on other embodiment of this invention. It is a side view which shows the state which removed the lock arm from the state shown in FIG. It is a perspective view of each mechanism shown in FIG. It is a perspective view which shows the state which removed the lock arm from the state shown in FIG. 27. It is an enlarged view of the main part of the lock arm shown in FIG. It is a figure which shows the thermal printer which concerns on the modification of another Embodiment of this invention, and is the perspective view of the main part which looked at the peripheral part of the operation lever from the inner side surface. It is a side view of the main part seen from the outer surface of the operation lever which shows the 1st stage (locked state) in the modified example of another embodiment of this invention. FIG. 31 is a side view of a main part of the first stage (locked state) shown in FIG. 31A as viewed from the inner side surface of the operating lever. FIG. 3 is a side view of a main part showing a second stage (intermediate state) in which the operation lever is pushed down from the state shown in FIG. 31A. It is a side view of the main part which looked at the 2nd stage (intermediate state) shown in FIG. 32A from the inner side surface of the operation lever. FIG. 3 is a side view of a main part showing a third stage (unlocked state) in which the operating lever is pushed down from the state shown in FIG. 32A. It is a side view of the main part which looked at the 3rd stage (unlocked state) shown in FIG. 33A from the inner side surface of the operation lever.

Hereinafter, an embodiment according to the present invention will be described with reference to the drawings.
As shown in FIGS. 1 and 2, the thermal printer 1 is a printer capable of printing on a roll paper-like recording paper (thermal paper) P and using the recording paper P as, for example, a ticket or a receipt. be.

The thermal printer 1 is installed, for example, in a store, and its operation is controlled by an information processing device (not shown). Therefore, the thermal printer 1 is controlled so as to print various information transmitted from the information processing apparatus on the recording paper P and discharge the printed recording paper P.

The thermal printer 1 is installed, for example, on the installation surface S of the store, and is formed in a cube shape as a whole. In the present embodiment, in the states shown in FIGS. 1 and 2, the direction perpendicular to the installation surface S is referred to as the vertical direction L1, and the direction orthogonal to each other in the plane parallel to the installation surface S is the front-rear direction L2. And left and right direction L3. Of the front-rear direction L2, the front is indicated by an arrow FW and the rear is indicated by an arrow BK. Therefore, in FIGS. 1 and 2, the lower left side is the front FW and the upper right side is the rear BK with respect to the paper surface.

The thermal printer 1 includes a casing (printer main body according to the present invention) 2, a printer cover 3, a printing unit 4 composed of a head unit 5 and a platen unit 6, and the recording paper P is discharged to the front FW. It is a so-called front-end type. In the illustrated example, the platen unit 6 is provided on the printer cover 3 side, and the head unit 5 is provided on the casing 2 side.
However, the present invention is not limited to this case, and for example, the head unit 5 may be provided on the printer cover 3 side and the platen unit 6 may be provided on the casing 2 side.

(casing)
The casing 2 is formed in a cube shape having an opening in the front FW by appropriately combining a synthetic resin material or a metal material, and has a plurality of outer surfaces 10 including a bottom surface 11 facing the installation surface S. .. However, the shape of the casing 2 is not limited to this case, and may be changed as appropriate.

Of the plurality of outer surfaces 10, the outer surface facing the bottom surface 11 in the vertical direction L1 is referred to as the top surface 12. Of the plurality of outer surfaces 10, the outer surface located on the front FW side is referred to as the front surface 13, and the outer surface located on the rear BK side is referred to as the rear surface 14. The front surface 13 and the rear surface 14 face each other in the front-rear direction L2. Further, among the plurality of outer surfaces 10, the outer surfaces facing the left-right direction L3 are referred to as a pair of side surfaces 15.

Inside the casing 2, a recording paper storage portion 16 capable of storing a roll-shaped recording paper P is formed through an opening formed in the front surface 13 of the casing 2. As a result, when the printer cover 3 is opened, the roll-shaped recording paper P can be inserted into the recording paper storage unit 16 from the front FW.

The printer cover 3 is connected to the lower portion of the casing 2 on the front surface 13 side via a rotating shaft portion 17, and the opening is closed so as to be openable. The printer cover 3 is connected around the rotation shaft portion 17 so as to rotate in an angle range of approximately 90 degrees.
As shown in FIG. 1, when the printer cover 3 is closed, there is a slight gap between the tip of the printer cover 3 and the casing 2. The recording paper P is pulled out from the inside of the casing 2 to the front FW by utilizing this gap and discharged. Therefore, this gap functions as a discharge port 18 for the recording paper P.

The casing 2 and the printer cover 3 configured as described above are locked when the printer cover 3 is closed, in association with the combination of the platen unit 6 and the head unit 5. As a result, the printer cover 3 is locked in the closed state.

Further, as shown in FIG. 1, the casing 2 is used to release the combination (lock) of the platen unit 6 and the head unit 5 at the corner where the front surface 13, the top surface 12, and one side surface 15 intersect. An operation lever 19 is provided. As a result, as shown in FIG. 2, the lock of the printer cover 3 can be released, and the printer cover 3 can be opened. The operation lever 19 can be pushed down, for example, downward.

The printer cover 3 is provided with an operation button 3a which is, for example, a power button or a paper feed button. The operation button 3a is arranged on the outer surface of the printer cover 3 in a state where it can be pressed and exposed. In the illustrated example, the operation buttons 3a are arranged below the operation lever 19 so as to be arranged in a line in the vertical direction L1.

(Printing unit)
As shown in FIGS. 2 to 5, the printing unit 4 includes a head unit 5 provided on the casing 2 side and a platen unit 6 provided on the printer cover 3 side and separably combined with the head unit 5. , Is equipped.

The head unit 5 is made of, for example, a synthetic resin head frame 20 that forms the basic skeleton of the head unit 5, and a metal head frame 20 that is combined with the head frame 20 so as to cover the head frame 20 from the front FW and the left-right direction L3. A head cover plate 21 and, for example, metal gear covers 22 and 23 combined with the head frame 20 so as to cover the head frame 20 from the left-right direction L3 are provided.

Further, the head unit 5 includes at least a thermal head 25, a movable blade 26, a drive mechanism 27, an operation lever 28, a return mechanism 29, and a platen lock mechanism 30. The thermal head 25, the movable blade 26, the drive mechanism 27, the operation lever 28, the return mechanism 29, and the platen lock mechanism 30 are mainly attached by using the head frame 20, and are covered by the head cover plate 21 and the gear covers 22, 23. It has been.

The head unit 5 configured as described above is mounted inside the casing 2. Specifically, the head unit 5 is located above the recording paper storage unit 16 and closer to the front surface 13 of the casing 2, and is attached to the casing 2 mainly by screwing the head frame 20.
In the present embodiment, the head unit 5 is attached so that the cutting edge 26a of the movable blade 26 faces downward. The head unit 5 will be described in detail later.

The platen unit 6 is made of, for example, a metal platen frame 40 formed of a synthetic resin, which forms the basic frame of the platen unit 6, and is combined with the platen frame 40 so as to cover the platen frame 40 from the front FW and the lateral L3. It includes a platen cover plate 41.
Further, the platen unit 6 includes at least a platen roller 45 and a fixed blade 46. The platen roller 45 and the fixed blade 46 are mainly attached by using the platen frame 40 and are covered by the platen cover plate 41.

The platen unit 6 configured as described above is attached to the inner surface of the printer cover 3 mainly via the platen cover plate 41. At this time, the platen unit 6 is attached at a position where it is separably combined with the head unit 5 as the printer cover 3 opens and closes.
In the present embodiment, the platen unit 6 is attached so that the cutting edge 46a of the fixed blade 46 faces upward.

The platen unit 6 will be described in detail.
As shown in FIGS. 3 to 6, the fixed blade 46 is supported by the platen frame 40 so that the cutting edge 46a faces the head unit 5 side when the head unit 5 and the platen unit 6 are combined. As shown in FIG. 6, the platen frame 40 is formed with a platen storage space 47 for storing the platen roller 45 in a portion located behind the fixed blade 46 in the rear BK, and the platen storage space 47 is interposed between the platen frame 40. A support wall 48 for supporting the platen roller 45 is formed so as to face the L3 in the left-right direction.

The platen roller 45 is a rubber roller that conveys the recording paper P to the outside of the printer cover 3, and is wound around a platen shaft 50 extending in the left-right direction L3. The platen roller 45 is housed in the platen storage space 47 with a part of the outer peripheral surface exposed on the head unit 5 side, and is rotatably supported by the support wall 48.
Specifically, cylindrical platen bearings 51 are covered on both ends of the platen shaft 50 extending outward in the left-right direction L3 from the platen roller 45. As a result, even if the pair of platen bearings 51 are pressed down, the platen roller 45 can be rotated. A driven gear 52 is fixed to one end of the platen shaft 50 on the outside of the platen bearing 51 in the left-right direction L3.

The support wall 48 is fixed by sandwiching the platen bearing 51 using, for example, a slit hole. As a result, the platen roller 45 is rotatably supported by the pair of support walls 48 via the pair of platen bearings 51 while being housed in the platen storage space 47.
The pair of platen bearings 51 extend outward from the support wall 48 in the left-right direction L3, and are provided on the head unit 5 side as shown in FIG. 5 when the printer cover 3 is closed. Each is housed in the groove 62.
Note that FIG. 5 mainly shows the platen roller 45 and the platen bearing 51 among the platen units 6.

Next, the head unit 5 will be described in detail.
As shown in FIGS. 3 to 5, the head unit 5 includes at least a thermal head 25, a movable blade 26, a drive mechanism 27, an operation lever 28, a return mechanism 29, and a platen lock mechanism 30.

As shown in FIG. 5, the thermal head 25 has a plurality of heat generating elements (not shown) arranged in a line along the left-right direction L3, and when the printer cover 3 is in the closed position, the platen roller 45 It is attached to the head frame 20 so as to face the head frame 20. The recording paper P can pass between the platen roller 45 and the thermal head 25.
A coil spring (not shown) that urges the thermal head 25 toward the platen roller 45 is interposed between the thermal head 25 and the head frame 20. As a result, the thermal head 25 can be reliably pressed against the recording paper P sent out by the platen roller 45, and good printing by the printing unit 4 is possible.

The head frame 20 has a pair of side wall portions 60, 61 located outside the support wall 48 of the platen frame 40 in the platen unit 6 in the left-right direction L3.
The pair of side wall portions 60 and 61 are each formed with a pair of accommodating grooves 62 into which a pair of platen bearings 51 can be individually fitted.
As shown in FIG. 7, the accommodating groove 62 is formed in a U-shape in a side view, and is formed with the opening 62a facing the front FW toward the platen unit 6 side. The groove bottom portion 62b in the accommodating groove 62 is formed flat.
Note that FIG. 7 illustrates the accommodating groove 62 formed in one side wall portion 60, and the illustration is appropriately omitted for each of the other components.

An inclined guide protrusion 63 is formed on the inner surface of the accommodating groove 62 so as to narrow the opening width from the opening 62a side toward the groove bottom 62b side, and guides the platen bearing 51 toward the groove bottom 62b side. It is formed. As a result, the accommodating groove 62 is formed so that the opening width 62a has the largest opening width, and the opening width is the narrowest in the vicinity of the apex 63a of the guide projection 63.
Since the guide protrusion 63 is formed in the accommodating groove 62, it is possible to guide the platen bearing 51 so as to drop along the guide protrusion 63 toward the groove bottom portion 62b.

Since the accommodating grooves 62 are formed in the pair of side wall portions 60 and 61 as described above, when the head unit 5 and the platen unit 6 are combined, as shown in FIGS. 5 and 7, the pair of platens The bearing 51 is fitted into the pair of accommodating grooves 62 and is accommodated therein. At this time, the platen bearing 51 is accommodated in the accommodating groove 62 in a state of being in contact with the groove bottom portion 62b.

As shown in FIG. 4, the movable blade 26 is attached to the head frame 20 via a drive mechanism 27 so that the cutting edge 26a faces the platen unit 6 side when the head unit 5 and the platen unit 6 are combined. ing. At this time, the movable blade 26 is arranged so as to face the fixed blade 46 in the vertical direction L1 and is arranged so as to overlap the fixed blade 46 in the front-rear direction L2 when moved to the cutting position P1. ing.
As shown in FIG. 8, the movable blade 26 is a V-shaped plate-shaped blade formed so that the length from the root to the cutting edge 26a gradually shortens from both ends toward the center. FIG. 8 is a perspective view showing a state in which the movable blade 26 is moved to the cutting position P1 and the recording paper P is cut between the fixed blade 46 and the movable blade 26.

As shown in FIG. 4, the movable blade 26 is attached to the drive rack 71 of the drive mechanism 27 via the movable blade holder 70. The movable blade 26 is configured to be movable in the vertical direction L1 with respect to the head frame 20 by the operation of the drive mechanism 27. As a result, the movable blade 26 is supported so as to be movable in the vertical direction L1 with respect to the fixed blade 46.

As shown in FIGS. 4, 9 and 10, the drive mechanism 27 is a mechanism for moving the movable blade 26 between the cutting position P1 and the standby position P2. The cutting position P1 is a position where the movable blade 26 rides on the fixed blade 46 and the movable blade 26 cuts the recording paper P together with the fixed blade 46 (see FIG. 8). The standby position P2 is a position where the movable blade 26 is appropriately separated from the fixed blade 46 (see FIG. 4).
The drive mechanism 27 includes a drive motor 75, a drive intermediate vehicle 76, a two-stage intermediate vehicle 77, a drive pinion 78, and a drive rack 71.

As shown in FIG. 10, the drive motor 75 is a motor that can rotate in the forward and reverse directions, and is fixed to the inside of one side wall portion 60 of the head frame 20. The drive shaft of the drive motor 75 is connected to the reduction mechanism 75a. Further, the output shaft 75b of the speed reduction mechanism 75a projects to the outside of L3 in the left-right direction from one side wall portion 60 of the head frame 20. The drive intermediate vehicle 76 is arranged outside the side wall portion 60 in the left-right direction L3 and is connected to the output shaft 75b of the speed reduction mechanism 75a. Therefore, the drive intermediate vehicle 76 rotates with the rotation of the drive motor 75 via the reduction mechanism 75a.

As shown in FIGS. 9 and 10, the two-stage intermediate vehicle 77 is arranged between the drive intermediate vehicle 76 and the drive pinion 78, and is rotatably supported by the intermediate support shaft 80.
The two-stage intermediate vehicle 77 includes a large-diameter intermediate vehicle 77a and a small-diameter intermediate vehicle 77b formed to have a smaller diameter than the large-diameter intermediate vehicle 77a. The large-diameter intermediate vehicle 77a meshes with the driving intermediate vehicle 76 when the operating lever 28 is located at the lock position P3. As a result, the entire two-stage intermediate vehicle 77 rotates as the drive intermediate vehicle 76 rotates. The small-diameter intermediate vehicle 77b is arranged outside the large-diameter intermediate vehicle 77a in the left-right direction L3 and meshes with the drive pinion 78.

The drive pinion 78 is arranged so as to be located on the operation lever 28 side and the drive rack 71 side of the small diameter intermediate wheel 77b, and is arranged coaxially with the pinion support shaft 81. It is fixed to the support shaft 81. As a result, the drive pinion 78 and the pinion support shaft 81 rotate integrally.
Further, the drive pinion 78 meshes with the small-diameter intermediate wheel 77b and also meshes with the drive rack teeth 71a in the drive rack 71.

As shown in FIG. 4, the drive rack 71 is arranged not only on one side wall portion 60 side of the head frame 20 but also on the other side wall portion 61 side, and is arranged on both sides of the head frame 20 in the left-right direction L3. Has been done. The pinion support shaft 81 is formed so as to penetrate the head frame 20 in the left-right direction L3, and connects a pair of drive pinions 78 arranged on both sides of the left-right direction L3. As a result, the pair of drive pinions 78 can rotate together in a synchronized state via the pinion support shaft 81.

The drive rack 71 is attached to both ends of the movable blade holder 70 along the left-right direction L3, and extends along the vertical direction L1. As a result, the drive rack 71 is combined with the movable blade 26 via the movable blade holder 70.
The drive rack 71 is formed with drive rack teeth 71a over the entire area. The pair of drive pinions 78 mesh with the drive rack teeth 71a. Therefore, it is possible to move the movable blade 26 between the standby position P2 and the cutting position P1 via the drive rack 71 as the pair of drive pinions 78 rotate.

Hereinafter, in order to facilitate understanding of the configuration, the drive pinion 78 and the drive rack 71 located on one side wall portion 60 side (drive motor 75 side) will be described in detail, and will be located on the other side wall portion 61 side. The description of the drive pinion 78 and the drive rack 71 will be omitted.

Since the drive mechanism 27 is configured as described above, as shown in FIGS. 4 and 9, the drive intermediate vehicle 76 and the two-stage intermediate vehicle 77 (large diameter intermediate vehicle 77a and small diameter intermediate vehicle 77a) are driven by the rotation of the drive motor 75. The drive pinion 78 can be rotated via the car 77b). Therefore, the drive rack 71 can be moved in the direction of the arrow F1 together with the return rack 130 described later of the return mechanism 29, and the movable blade 26 can be moved in the same direction. As a result, the movable blade 26 can be moved from the standby position P2 to the cutting position P1.

On the other hand, by rotating the drive motor 75 in the reverse direction, the drive pinion 78 can be rotated in the reverse direction via the drive intermediate vehicle 76 and the two-stage intermediate vehicle 77. Therefore, the drive rack 71 can be moved together with the return rack 130 in the direction of arrow F2, and the movable blade 26 can be moved in the same direction. As a result, the movable blade 26 can be moved from the cutting position P1 to the standby position P2 and returned.

By the way, the intermediate support shaft 80 that supports the above-mentioned two-stage intermediate vehicle 77 is fixed to a swing plate 90 that is swingably arranged around the pinion support shaft 81.
As shown in FIGS. 7 and 9 to 11, the swing plate 90 is formed with an insertion hole 91 that penetrates the swing plate 90 in the left-right direction L3 and inserts the pinion support shaft 81. The swing plate 90 is arranged so as to be swingable along the wall surface of one side wall portion 60 in a state where the pinion support shaft 81 is inserted into the insertion hole 91.

The swing plate 90 extends from the insertion hole 91 toward the first plate portion 92 extending between the drive intermediate wheel 76 and the drive rack 71, and from the insertion hole 91 toward the swing axis O2 of the lock arm 140 described later. It is provided with a second plate portion 93.

The intermediate support shaft 80 is formed so as to extend outward from the first plate portion 92 in the left-right direction L3. As a result, the two-stage intermediate wheel 77 supported by the intermediate support shaft 80 can swing around the pinion support shaft 81 along with the swing plate 90.
The second plate portion 93 is formed with a locking projection 94 and an engaging pin 95 so as to project outward in the left-right direction L3.

The swing plate 90 configured in this way is always urged in the direction in which the large-diameter intermediate vehicle 77a of the two-stage intermediate vehicle 77 meshes with the driving intermediate vehicle 76 by the urging force of the first urging member 100. ..
The first urging member 100 is, for example, a coil spring, the coil portion 100a supported by the coil support shaft 105 projecting from one side wall portion 60, and the first coil end locked to the head frame 20. It has a portion 100b and a second coil end portion 100c locked to a locking projection 94 of the swing plate 90.

As a result, in the swing plate 90, the second plate portion 93 is urged toward the operation lever 28 side by the urging force (elastic restoring force) of the first urging member 100, so that the large-diameter intermediate wheel 77a is driven. It is positioned while being pressed against the intermediate wheel 76.
The first urging member 100 is not limited to the coil spring, and may be, for example, a leaf spring or the like.

Further, in the swing plate 90, the engagement pin 95 is pushed up by the push-up cam 113 described later with the operation of the operation lever 28, so that the pinion support shaft 81 opposes the urging force of the first urging member 100. The two-stage intermediate vehicle 77 is configured to swing around the center of the vehicle so as to be separated from the drive intermediate vehicle 76. As a result, it is possible to disengage the engagement between the two-stage intermediate vehicle 77 and the drive intermediate vehicle 76.

As shown in FIGS. 4, 9 and 10, the operating lever 28 is arranged on one side wall portion 60 side of the head frame 20 and is rotatably supported via the lever support shaft 106.
The operating lever 28 is a clock with one side wall portion 60 viewed from the outside in the left-right direction L3 from the lock position P3 toward the meshing release position P4 and the lock release position P5, which will be described later, with the lever support shaft 106 as the center. It is configured so that it can be pushed in the direction.

As shown in FIG. 11, the lever support shaft 106 projects from the inner surface of the gear cover 22 toward one side wall portion 60 side. The central axis of the lever support shaft 106 is the rotation axis O1 of the operating lever 28.

The lock position P3 is a position where the platen unit 6 is held in the locked state with respect to the head unit 5. At the meshing release position P4, the swing plate 90 is swung by the push-up cam 113 described later in the operation lever 28, and the meshing between the large-diameter intermediate wheel 77a of the two-stage intermediate wheel 77 and the drive intermediate wheel 76 is disengaged. The position. The unlocked position P5 is a position where the locked state of the platen unit 6 with respect to the head unit 5 is released.

As shown in FIGS. 9 to 11, a lever plate 110 formed in a side view fan shape is formed at the base end portion of the operating lever 28.
A planetary shaft 111 is projected from the outer surface of the lever plate 110 toward the outside of L3 in the left-right direction. A lever protrusion 112 that engages with a lock arm 140, which will be described later, is formed on the inner surface of the lever plate 110. Further, the lever plate 110 is formed with a push-up cam 113 and a regulation projecting piece 114 that bulge outward in the radial direction.

The planetary shaft 111 is formed at a position offset from the lever support shaft 106. The push-up cam 113 is arranged counterclockwise with respect to the engagement pin 95 formed on the swing plate 90, and engages when the operating lever 28 rotates from the lock position P3 toward the unlock position P5. It is said that it can be contacted with the pin 95. Further, on the outer surface of the push-up cam 113, a locking projection 115 is formed so as to project outward in the left-right direction L3.

The regulation projecting piece 114 is arranged counterclockwise with respect to the push-up cam 113, and when the operating lever 28 is located at the lock position P3, the regulation wall portion 116 formed on the head frame 20 is clocked with respect to the regulation wall portion 116. It is in contact from the direction side.
Therefore, the entire operating lever 28 is restricted from rotating clockwise any more, and is thereby positioned at the lock position P3.
When the operation lever 28 moves to the unlocked position P5 and is further pushed down, it comes into contact with the regulation wall portion 117 of the gear cover 22 shown in FIGS. 3 and 11 from the counterclockwise direction. It is possible. Therefore, the operating lever 28 is restricted from being pushed down further beyond the unlocked position P5.

The tip of the operating lever 28 is fitted inside the connecting body 19a (see FIG. 2) of the operating lever 19 provided on the casing 2. Therefore, the operation lever 28 is operated in conjunction with the operation of the operation lever 19. As a result, by operating the operation lever 19, the operation lever 28 can be operated from the lock position P3 to the unlock position P5 in conjunction with the operation lever 19.

As shown in FIGS. 9 and 10, the operating lever 28 configured as described above is always urged in the direction toward the lock position P3 (clockwise) by the urging force of the second urging member 120. ..
The second urging member 120 is, for example, a coil spring, and is a second coil portion 120a supported by a coil support shaft (not shown) projecting from the inner surface of the gear cover 22 and locked to the inner surface of the gear cover 22. It has one coil end 120b and a second coil end 120c locked to the locking projection 115 of the operating lever 28.

As a result, the operating lever 28 is urged clockwise by the urging force (elastic restoring force) of the second urging member 120, so that the tip end portion of the operating lever 28 is urged in the direction toward the lock position P3. ing. As described above, since the regulation projecting piece 114 of the operating lever 28 comes into contact with the regulation wall portion 116 of the head frame 20, further rotation is restricted and the position is positioned at the lock position P3.
The second urging member 120 is not limited to the coil spring, and may be, for example, a leaf spring or the like.

As shown in FIG. 4, the return mechanism 29 accompanies the operation lever 28 from the lock position P3 to the unlock position P5 in a state where the movable blade 26 is stopped at the cutting position P1 due to, for example, the occurrence of paper jam. This mechanism uses the operating force (rotational force) to move the movable blade 26 from the cutting position P1 to the standby position P2 before the platen lock mechanism 30 switches the platen roller 45 to the unlocked state.

As shown in FIGS. 9 to 12, the return mechanism 29 is coaxial with the return rack 130 formed in the drive rack 71, the return pinion 131 that meshes with the rack teeth 130a of the return rack 130, and the rotation axis O1 of the operating lever 28. The return gear 132 and the sun gear 133 rotatably supported around the rotation axis O1, the planetary gear 134 that meshes with the sun gear 133 and revolves with the movement of the operating lever 28, and the planetary gear 134 are arranged in the above position. It is equipped with an internal gear 135 that meshes with each other. The sun gear 133, the planetary gear 134, and the internal gear 135 constitute an acceleration mechanism 136 (see FIG. 12).

In the present embodiment, the case where the return gear 132 and the sun gear 133 are configured as one member is taken as an example, but the present invention is not limited to this case. For example, if the return gear 132 and the sun gear 133 can rotate integrally (co-rotate), the return gear 132 and the sun gear 133 may be formed separately and then combined.

The return pinion 131 is rotatably supported by the pinion support shaft 81 in a state of being arranged outside the drive pinion 78 in the left-right direction L3. As a result, the return pinion 131 is arranged coaxially with the drive pinion 78. The return pinion 131 can be meshed with the return gear 132 that rotates in conjunction with the operation of the operation lever 28, and rotates by the rotational force from the return gear 132.
Further, the return pinion 131 can mesh with the rack teeth 130a in the return rack 130.

As shown in FIGS. 9 and 10, the return rack 130 is integrally formed with the drive rack 71 in a state of being arranged outside the drive rack 71 in the drive mechanism 27 in the left-right direction L3. The return rack 130 has a plurality of rack teeth 130a. These plurality of rack teeth 130a are formed so as to be located not on the cutting edge 26a side of the movable blade 26 but on the root side. As a result, the return rack 130 meshes with the return pinion 131 when the movable blade 26 is located at the cutting position P1, and is released from meshing with the return pinion 131 when the movable blade 26 is located at the standby position P2.

In the illustrated example, the drive rack 71 and the return rack 130 are integrally formed, but the present invention is not limited to this case, and the return rack 130 may be formed separately from the drive rack 71. .. However, by integrally forming the drive rack 71 and the return rack 130, the return rack 130 can be provided without increasing the number of parts, so that the configuration can be simplified and the cost can be reduced. It is preferable because it can be planned.

Of the plurality of rack teeth 130a, the rack teeth 130a located on the cutting edge 26a side of the movable blade 26 are displaceable rack teeth 130b.
The rack teeth 130b are formed at the tip of the rack arm 139. The base end portion of the rack arm 139 is connected to the end portion of the return rack 130 located on the cutting edge 26a side of the movable blade 26. Therefore, the rack arm 139 is a cantilever arm that can be elastically deformed in a direction away from the return pinion 131 with the base end as a fulcrum.
As a result, the rack arm 139 can be elastically deformed in a direction away from the return pinion 131, and the rack teeth 130b can be retracted to the outside in the radial direction of the return pinion 131.

The reason why the rack teeth 130b of the return rack 130 are formed so as to be retractable outward in the radial direction of the return pinion 131 will be briefly described.
For example, when the return rack 130 moves in the direction of the arrow F1 shown in FIG. 9, it is conceivable that the rack teeth 130b of the return rack 130 come into contact with the tooth tips of the tooth portions of the return pinion 131. In this case, the movement of the return rack 130 may be blocked by the tooth tips of the return pinion 131.
In consideration of this, by forming the rack teeth 130b at the tip of the rack arm 139, the rack teeth 130b are retracted radially outward of the return pinion 131 due to the elastic deformation of the rack arm 139, and the teeth of the return pinion 131. It is configured so that it can overcome the tip. Therefore, after the rack teeth 130b get over the tooth tips of the return pinion 131, the rack teeth 130b are returned to their original positions by utilizing the elastic restoring force of the rack arm 139, and the returned rack teeth 130b are returned to the next pinion 131. It is possible to properly engage with the teeth of the tooth. As a result, the rack teeth 130b of the return rack 130 and the return pinion 131 can be appropriately meshed without causing the inconvenience of hindering the movement of the return rack 130.

As shown in FIGS. 9 and 10, the return gear 132 is rotatably supported by the lever support shaft 106 in a state of being arranged outside the lever plate 110 in the operating lever 28 in the left-right direction L3. As a result, the return gear 132 is arranged coaxially with the rotation axis O1 of the operating lever 28.

The return gear 132 includes a gear plate 132a and a plurality of gear tooth portions 132b formed along the outer peripheral edge of the gear plate 132a. The plurality of gear tooth portions 132b are formed in a range extending substantially half of the circumference of the gear plate 132a, not the entire circumference. These plurality of gear tooth portions 132b are made capable of meshing with the return pinion 131.

Of the plurality of gear teeth 132b, the gear teeth 132b that first mesh with the return pinion 131 by operating the operation lever 28 from the lock position P3 to the unlock position P5 are moved inward in the radial direction of the return gear 132. It is possible to displace it toward it, and it is possible to retract it from the tooth portion of the return pinion 131.

The gear tooth portion 132b is formed at the tip end portion of the elastic arm portion 132c. The base end portion of the elastic arm portion 132c is integrally formed with the unformed portion of the gear tooth portion 132b of the outer peripheral edge of the gear plate 132a, and extends clockwise along the outer peripheral edge of the gear plate 132a in an arc shape. .. As a result, the elastic arm portion 132c is cantilevered and supported on the outer peripheral edge of the gear plate 132a via the proximal end portion, and is elastically deformable in the radial direction with the proximal end portion as a fulcrum.
As a result, the elastic arm portion 132c is elastically deformed toward the gear plate 132a side, so that the gear tooth portion 132b can be displaced inward in the radial direction of the return gear 132 and retracted from the tooth portion of the return pinion 131. It is possible to do.

As shown in FIG. 12, the sun gear 133 is integrally formed on the inner surface of the gear plate 132a and is arranged coaxially with the rotation axis O1 of the operating lever 28. As a result, the sun gear 133 can rotate around the rotation axis O1 together with the return gear 132.

The planetary gear 134 is rotatably supported by the operating lever 28 via the planetary shaft 111 in a state of being meshed with the sun gear 133. As a result, the planetary gear 134 revolves around the rotation axis O1 following the movement of the operation lever 28 by rotating the operation lever 28 around the rotation axis O1.
An internal gear 135 with which the planetary gear 134 meshes is formed on the inner surface of the gear cover 22. Therefore, the planetary gear 134 revolves with the movement of the operating lever 28, so that the planetary gear 134 can rotate while meshing with the internal gear 135.

By rotating the planetary gear 134 in this way, the sun gear 133 and the return gear 132 can be rotated around the rotation axis O1, and the gear teeth 132b of the return gear 132 can be engaged with the return pinion 131. It is possible.

As shown in FIG. 5, the platen lock mechanism 30 includes lock arms 140 and 150 that can swing around the swing axis O2 parallel to the platen roller 45, and locks the platen roller 45 and locks the lock. It is a mechanism to switch between the unlocked state and the unlocked state.

As shown in FIGS. 5, 9 and 10, one lock arm 140 is arranged on one side wall portion 60 side of the head frame 20, and the other lock arm 150 is arranged on the other side wall portion 61 side. ..
When the operating lever 28 is located at the lock position P3, the pair of lock arms 140 and 150 press the platen bearing 51 housed in the accommodating groove 62 from the opening 62a side, and the operating lever 28 locks. As it moves from the position P3 toward the unlocking position P5 side, it swings around the swing axis O2 from the platen unit 6 toward the head unit 5 side, and is separated from the platen bearing 51 in the accommodating groove 62. Allows the platen bearing 51 to separate from the platen bearing 51.

Therefore, the platen lock mechanism 30 of the present embodiment can lock the pair of platen bearings 51 at the same time and unlock them at the same time by using the pair of lock arms 140 and 150.

One lock arm 140 and the other lock arm 150 are connected via a long connecting shaft portion 141 extending along the left-right direction L3.
As shown in FIG. 10, the connecting shaft portion 141 is a columnar shaft, is formed so as to penetrate the head frame 20 in the left-right direction L3, and rotates on one side wall portion 60 and the other side wall portion 61. It is supported as much as possible. The central axis of the connecting shaft portion 141 is the swing axis O2.

One lock arm 140 and the other lock arm 150 are connected to both ends of the connecting shaft portion 141, respectively. As a result, one lock arm 140 and the other lock arm 150 can swing in a state of being synchronized with the swing axis O2 via the connecting shaft portion 141.

The connecting shaft portion 141 is arranged so as to be located between the accommodating groove 62 and the return gear 132 in the vertical direction L1 and located behind the accommodating groove 62 in the front-rear direction L2.

In this embodiment, a case where a pair of lock arms 140 and 150 arranged in the left-right direction L3 are oscillatingly connected via a connecting shaft portion 141 is taken as an example. It is not limited. For example, the pair of lock arms 140, 150 and the connecting shaft portion 141 may be integrally formed by bending one sheet metal or the like to integrally form the pair.

One lock arm 140 will be described in detail.
As shown in FIG. 13, the lock arm 140 is arranged above the accommodating groove 62 and is formed so as to extend in the front-rear direction L2. The base end portion of the lock arm 140 is connected to the end portion of the connecting shaft portion 141. A lock claw portion 145 is formed at the tip of the lock arm 140 to cover the platen bearing 51 accommodated in the accommodating groove 62 from the opening 62a side of the accommodating groove 62. As a result, the platen bearing 51 can be held so as to sandwich the platen bearing 51 between the lock claw portion 145 and the groove bottom portion 62b in the accommodating groove 62.

The outer surface of the lock claw portion 145 is an inclined guide surface 145b that guides the platen bearing 51 into the accommodating groove 62 when the platen bearing 51 is set in the accommodating groove 62. The guide surface 145b is formed so that a V-shaped V-groove is defined in a side view from the guide projection 63 on the accommodating groove 62 side.

Further, an engaging wall portion 146 projecting outward in the left-right direction L3 is formed at the base end portion of the lock arm 140. When the operating lever 28 is operated from the locking position P3 to the unlocking position P5, the engaging wall portion 146 swings the swing plate 90 via the engaging pin 95 after the push-up cam 113 swings the operating lever. It is a wall portion that the lever protrusion 112 of 28 comes into contact with.

As a result, the entire lock arm 140 is pushed from the lever protrusion 112 via the engaging wall portion 146 as the operating lever 28 is operated, and is configured to swing clockwise around the swing axis O2. Has been done. That is, the lock arm 140 is configured to swing upward about the swing axis O2 so as to move from the platen unit 6 side to the head unit 5 side.
Therefore, the lock claw portion 145 of the lock arm 140 gradually separates from the platen bearing 51 as the operation lever 28 is operated, and when the operation lever 28 reaches the lock position P3, the lock claw portion 145 moves from the accommodating groove 62 to the head unit 5 side. It retracts and opens the opening 62a. This makes it possible to allow the platen bearing 51 to separate from the accommodation groove 62.

Further, the lock arm 140 pushes the platen bearing 51 from the groove bottom 62b of the accommodating groove 62 toward the opening 62a as the operating lever 28 moves from the locking position P3 to the unlocking position P5. A push-up arm 147 for raising is formed.
The push-up arm 147 is arranged behind the groove bottom portion 62b in the rear BK, and is formed so as to extend downward from the lock arms 140 and 150. The surface of the push-up arm 147 facing the platen bearing 51 side is formed so as to extend parallel to the groove bottom portion 62b, and is a push-up surface 147a that pushes up the platen bearing 51.

When the operating lever 28 is located at the lock position P3, a gap is secured between the push-up surface 147a and the platen bearing 51. As a result, the push-up arm 147 stands by in non-contact with the platen bearing 51 when the operating lever 28 is located at the lock position P3.

In particular, since the push-up arm 147 is formed to be long downward, when pushing up the platen bearing 51 in the accommodating groove 62, the platen bearing 51 can be greatly pushed up toward the opening 62a. There is. Specifically, it is possible to push up the platen bearing 51 so that the roller center of the platen roller 45 moves toward the opening 62a from the apex 63a of the guide projection 63 formed in the accommodation groove 62. There is.

The lock arm 140 configured as described above receives a urging force for urging the other lock arm 150 (see FIG. 5) arranged on the other side wall portion 61 side of the head frame 20, and receives a urging force on the platen unit 6 side. It is urged counterclockwise toward. As a result, the lock arm 140 is constantly urged so that the lock claw portion 145 is in a posture of covering the platen bearing 51 from the opening 62a side.

Next, the other lock arm 150 will be described with reference to FIG. However, since the other lock arm 150 has basically the same configuration as the one lock arm 140, the same reference numerals are given to the same configuration, and the description thereof will be omitted.

As shown in FIG. 14, the other lock arm 150 is formed with a locking projection 151 projecting outward in the left-right direction L3. Then, the lock arm 150 is constantly urged by the urging force of the third urging member (the urging member according to the present invention) 160 so that the lock claw portion 145 is in a posture of covering the platen bearing 51 from the opening 62a side. Has been done.

The third urging member 160 is, for example, a coil spring, which is a coil portion 160a supported by a coil support shaft (not shown) projecting from the inner surface of the other gear cover 23, and a third urging member 160 locked to the head frame 20. It has one coil end 160b and a second coil end 160c locked to a locking projection 151 of the lock arm 150.

As a result, the lock arm 150 is urged clockwise by the urging force (elastic restoring force) of the third urging member 160 in the state shown in FIG. As a result, one lock arm 140 is urged counterclockwise in the state shown in FIG.
The third urging member 160 is not limited to the coil spring, and may be, for example, a leaf spring or the like.

As shown in FIG. 5, when the platen unit 6 of the present embodiment is combined with the head unit 5, the driven gear 52 is arranged outside the other lock arm 150 in the left-right direction L3. The driven gear 52 is capable of meshing with a platen train wheel mechanism (not shown) arranged on the other side wall portion 61 side of the head frame 20. The platen train wheel mechanism operates by receiving power from a drive motor (not shown) for driving the platen roller 45, and plays a role of transmitting the power to the driven gear 52.
As a result, when the head unit 5 and the platen unit 6 are combined, the platen roller 45 can be rotated to feed the recording paper P.

(Operation of thermal printer)
Next, the operation of the thermal printer 1 configured as described above will be described.
First, a case where the head unit 5 and the platen unit 6 are combined will be described.
In this case, as shown in FIG. 2, the platen unit 6 is moved by closing the printer cover 3 after inserting the roll-shaped recording paper P into the recording paper storage portion 16 of the casing 2 and setting the paper. It can be brought closer to the head unit 5. Then, as shown in FIG. 1, by completely closing the printer cover 3, the head unit 5 and the platen unit 6 can be combined with the recording paper P sandwiched between the thermal head 25 and the platen roller 45. can.

As the printer cover 3 is closed, the platen bearing 51 of the platen roller 45 fits into the accommodation groove 62 while being guided by the guide projection 63 of the accommodation groove 62 and the guide surface 145b of the lock claw portion 145. It is guided and accommodated in the accommodating groove 62. At this time, the platen bearing 51 fits the lock claw portion 145 into the accommodating groove 62 while slightly pushing it away against the urging force of the third urging member 160.

After being pushed by the platen bearing 51, the lock arms 140 and 150 swing around the swing axis O2 by the urging force of the third urging member 160 to return to their original positions, and use the lock claw portion 145. The platen bearing 51 is pressed from the opening 62a side of the accommodating groove 62.
As a result, as shown in FIG. 5, the pair of lock arms 140 and 150 can be used to press each of the pair of platen bearings 51 accommodated in the pair of accommodating grooves 62, so that the inside of the accommodating groove 62 can be pressed. It is possible to prevent the platen bearing 51 from coming off. Therefore, the platen lock mechanism 30 can be used to maintain the platen roller 45 in the locked state.

As a result, the combination of the head unit 5 and the platen unit 6 can be locked, and at the same time, the printer cover 3 can be locked with respect to the casing 2.
By combining the head unit 5 and the platen unit 6, the thermal head 25 and the platen roller 45 are pressed against each other at a predetermined pressure with the recording paper P sandwiched between them. Further, the recording paper P is in a state of being pulled out from the discharge port 18 to the outside of the casing 2 after passing between the movable blade 26 and the fixed blade 46. Further, the driven gear 52 of the platen roller 45 is in a state of meshing with the platen train wheel mechanism on the head unit 5 side.

Next, a case where various information is printed on the recording paper P will be briefly described.
In this case, the drive motor is driven to rotate the driven gear 52 via the platen train wheel mechanism. As a result, the platen roller 45 can be rotated, and the recording paper P sandwiched between the platen roller 45 and the thermal head 25 can be fed toward the discharge port 18.
At the same time, a control signal corresponding to the print data is output to the thermal head 25 to appropriately heat the heat generating element. As a result, various characters, figures, and the like can be clearly printed on the paper-fed recording paper P.
The printed recording paper P passes between the fixed blade 46 and the movable blade 26.

Next, a case where the recording paper P is cut will be briefly described.
In this case, the drive motor 75 is driven to rotate the drive intermediate vehicle 76 shown in FIG. As a result, the drive pinion 78 can be rotated via the two-stage intermediate vehicle 77 (large-diameter intermediate vehicle 77a and small-diameter intermediate vehicle 77b), and the drive rack 71 can be moved together with the return rack 130 in the direction of arrow F1. .. Therefore, the movable blade 26 can be moved from the standby position P2 to the cutting position P1, and as shown in FIG. 8, the recording paper P can be sandwiched between the fixed blade 46 and cut. As a result, the cut recording paper P can be used as, for example, a receipt or a ticket.

After cutting the recording paper P, the drive motor 75 is rotated in the reverse direction. As a result, the drive pinion 78 can be rotated in the reverse direction via the drive intermediate vehicle 76 and the two-stage intermediate vehicle 77, and as shown in FIG. 9, the drive rack 71 can be moved together with the return rack 130 in the direction of arrow F2. can. Therefore, the movable blade 26 can be moved from the cutting position P1 to the standby position P2 and returned.

Further, when the recording paper P is cut, the return pinion 131 is in a state in which the meshing with the gear tooth portion 132b of the return gear 132 is released, and idling is allowed. Therefore, when the movable blade 26 moves to the cutting position P1, even if the rack teeth 130a and 130b of the return rack 130 mesh with the return pinion 131, the return pinion 131 can idle. Therefore, the drive rack 71 and the return rack 130 can be moved without being affected by the return pinion 131, and the recording paper P can be cut.

Next, when a paper jam occurs between the movable blade 26 and the fixed blade 46, the platen unit 6 is unlocked by operating the operation lever 28 to release the paper jam, and the printer is used. A series of operations when the cover 3 is opened will be described.
If a paper jam occurs during cutting of the recording paper P, as shown in FIG. 15, the movable blade 26 is stopped at the cutting position P1 on the fixed blade 46.

In this case, as shown in FIG. 15, the operating lever 28 is operated from the lock position P3 toward the unlock position P5 side against the urging force of the second urging member 120. As a result, the operation lever 28 can be moved so as to rotate counterclockwise around the rotation axis O1, and the planetary gear 134 meshing with the internal gear 135 is moved along with the movement of the operation lever 28. It can revolve counterclockwise around the rotation axis O1 while rotating clockwise around 111.
Then, as the planetary gear 134 rotates, the sun gear 133 and the return gear 132 can be rotated counterclockwise about the rotation axis O1.

When the operating lever 28 rotates counterclockwise, as shown in FIG. 16, the push-up cam 113 comes into contact with the engaging pin 95, and an external force is applied to the swing plate 90 via the engaging pin 95. Give. Therefore, as shown in FIG. 17, the swing plate 90 can be pushed up by the push-up cam 113 by further operating the operation lever 28, and the pinion support shaft 81 can be resisted by the urging force of the first urging member 100. The swing plate 90 can be swung clockwise around the center.

As a result, the two-stage intermediate vehicle 77 attached to the swing plate 90 can be separated from the drive intermediate vehicle 76, and the engagement between the two-stage intermediate vehicle 77 and the drive intermediate vehicle 76 can be released.
Therefore, the position of the operating lever 28 at this time corresponds to the meshing release position P4.

Further, at the same time as the swing plate 90 swings, the sun gear 133 and the return gear 132 rotate counterclockwise with the operation of the operation lever 28. Therefore, as shown in FIG. 17, the two-stage intermediate vehicle 77 and the drive intermediate vehicle At the timing when the meshing with 76 is released, the first gear tooth portion 132b of the return gear 132 can be meshed with the return pinion 131. As a result, the return pinion 131 can be rotated clockwise.

Therefore, by further operating the operation lever 28 from the meshing release position P4 shown in FIG. 17 toward the lock release position P5 side, the remaining gear tooth portions 132b of the return gear 132 are returned as shown in FIGS. 18 and 19. It can be sequentially meshed with the pinion 131, and the return pinion 131 can be continuously rotated clockwise.
Therefore, the return rack 130 meshing with the return pinion 131 can be moved in the direction of the arrow F2, and the movable blade 26 can be forcibly returned from the cutting position P1 to the standby position P2. As a result, the state in which the movable blade 26 overlaps the fixed blade 46 can be eliminated, and the paper jam can be released.

When the movable blade 26 is returned to the standby position P2 by using the return pinion 131, the drive rack 71 moves together with the return rack 130, so that the drive pinion 78 rotates. At this time, as described above, since the engagement between the two-stage intermediate vehicle 77 and the drive intermediate vehicle 76 is released, the drive pinion 78 and the two-stage intermediate vehicle 77 meshing with the drive pinion 78 can be idled. can. Therefore, the movable blade 26 can be returned to the standby position P2 without being affected by the drive pinion 78 and the two-stage intermediate vehicle 77.

When the movable blade 26 returns to the standby position P2, as shown in FIG. 19, the rack teeth 130a and 130b of the return rack 130 are in a state of being separated from the return pinion 131. Therefore, when the movable blade 26 is returned to the standby position P2 and the paper jam is released, the meshing between the rack teeth 130a and 130b of the return rack 130 and the return pinion 131 can be released.

Further, as shown in FIG. 19, at the timing when the movable blade 26 returns to the standby position P2, the lever protrusion 112 of the operating lever 28 comes into contact with and engages with the engaging wall portion 146 of one of the lock arms 140. An external force is applied to the lock arm 140 via the wall portion 146. As a result, the lock arm 140 can be pushed up, and the lock arm is centered on the swing axis O2 so as to go from the platen unit 6 side to the head unit 5 side against the urging force of the third urging member 160. The 140 can be swung. Therefore, the lock claw portion 145 can be gradually separated from the platen bearing 51 as the lock arm 140 swings.

Then, by further operating the operating lever 28 and moving it to the unlocking position P5 as shown in FIG. 20, the lock arm 140 can be retracted from the accommodating groove 62 to the head unit 5 side, and the lock claw portion 145 can be retracted. Can be largely separated from the platen bearing 51 to open the opening 62a. As a result, the platen bearing 51 can be allowed to separate from the accommodation groove 62.

Further, in conjunction with the movement of the lock arm 140 described above, as shown in FIG. 20, the platen bearing 51 is pushed from the groove bottom portion 62b of the accommodating groove 62 toward the opening 62a by using the push-up arm 147. Can be raised. In particular, when the operating lever 28 reaches the unlocking position P5, as shown in FIG. 20, the platen roller 45 is placed closer to the opening 62a than the apex 63a of the guide projection 63 by using the push-up arm 147. The platen bearing 51 can be pushed up so that the center of the roller moves.

Since the other lock arm 150 operates in synchronization with the one lock arm 140 via the connecting shaft portion 141, it can be operated in the same manner as described above.
Therefore, by positioning the operating lever 28 at the unlocked position P5, the platen roller 45 can be switched to the unlocked state by using the platen lock mechanism 30, and the head unit 5 and the platen unit 6 can be separated. can. As a result, the printer cover 3 to which the platen unit 6 is attached can be opened.

As described above, according to the printing unit 4 and the thermal printer 1 of the present embodiment, the lock arms 140 and 150 can be used to prevent the platen bearing 51 from coming off from the accommodation groove 62, so that the platen roller 45 Can be securely locked. Moreover, since the lock arms 140 and 150 are urged by the third urging member 160 so as to maintain the locked state, the lock arm 140 and 150 are unintentionally swung around the swing axis O2 to release the locked state. It is possible to prevent it from being stored.

Further, in conjunction with the operation of the operation lever 28, not only the lock arms 140 and 150 are retracted from the accommodating groove 62, but also the platen bearing 51 is forcibly directed toward the opening 62a side by using the push-up arm 147. Since it can be pushed up, the platen roller 45 can be separated from the accommodating groove 62 without being affected by the urging force of the third urging member 160. Therefore, it is not necessary to operate the operating lever 28 with an excessive force, the lock of the platen roller 45 can be released with a small operating force, and the head unit 5 and the platen unit 6 can be smoothly separated.

Moreover, when the platen roller 45 is unlocked, the lock arms 140 and 150 are swung from the platen unit 6 side toward the head unit 5 side unlike the conventional case, so that the lock arms 140 and 150 can be moved to the platen unit 6 side. There is no need to secure a movable space for making it. Therefore, the platen unit 6 can be made smaller and thinner by that amount, and the outer size of the entire printing unit 4 can be made compact.

Further, since the platen bearings 51 are pressed by using the lock arms 140 and 150, one platen bearing 51 is locked, and the other platen bearing 51 is not locked or the lock is insufficient, so-called one-sided tightening (one-sided up). ) Is unlikely to occur. Therefore, it is not necessary to add a mechanism or the like for preventing one-sided tightening, and the design can be facilitated.
Further, since the lock arms 140 and 150 and the push-up arm 147 are integrally formed into one component, the number of components can be reduced and the configuration can be simplified.

Further, when the platen bearing 51 is pushed up by using the push-up arm 147, the platen bearing is moved so that the roller center of the platen roller 45 moves toward the opening 62a of the push-up arm 147 from the apex portion 63a of the guide projection 63. Forcibly push up 51 greatly. Therefore, the platen bearing 51 can be pushed up to the vicinity of the opening 62a in the accommodating groove 62 to shift to a state in which the platen bearing 51 is substantially detached, so that the work of separating the head unit 5 and the platen unit 6 can be performed more easily. can.

Further, since the return mechanism 29 is provided, even if a paper jam occurs between the fixed blade 46 and the movable blade 26 and the movable blade 26 stops at the cutting position P1 due to this paper jam, the operation is performed. By operating the lever 28, the platen roller 45 can be unlocked after the paper jam is released. Therefore, the printing unit 4 and the thermal printer 1 can be very easy to use.
In particular, as the operation lever 28 is operated from the lock position P3 to the lock release position P5, the release of the paper jam and the release of the platen roller 45 can be performed in conjunction with each other in a series of flows. Therefore, the printing unit 4 and the thermal printer 1 can be made even easier to use.

In addition, since the acceleration mechanism 136 using the planetary gear 134 is provided, it is possible to secure a large rotational force of the return gear 132 with respect to the operation stroke amount of the operation lever 28. Therefore, it is possible to secure the rotation amount of the return gear 132 required to return the movable blade 26 to the standby position P2 side in a state where the operation stroke amount of the operation lever 28 is suppressed to be smaller. As a result, the operability of the operation lever 28 can be ensured satisfactorily.

Further, the return gear 132 of the present embodiment is capable of retracting the gear tooth portion 132b that first meshes with the return pinion 131 inward in the radial direction of the return gear 132. Therefore, it can be reliably engaged with the return pinion 131 from the gear tooth portion 132b.

This point will be briefly described.
For example, as shown in FIG. 17, when the gear tooth portion 132b of the return gear 132 meshes with the return pinion 131, the tooth tip 131a of the pinion tooth in the return pinion 131 comes into contact with the tooth tip of the gear tooth portion 132b. Therefore, it is conceivable that the rotation of the return gear 132 may be hindered by the return pinion 131.
However, even in such a case, the gear tooth portion 132b can be retracted inward in the radial direction of the return gear 132 due to the elastic deformation of the elastic arm portion 132c. As a result, as the return gear 132 rotates, the gear tooth portion 132b can be moved so as to get over the tooth tip 131a of the pinion tooth. Therefore, after overcoming the tooth tip 131a of the pinion tooth, the gear tooth portion 132b can be returned from the retracted position to the original position by utilizing the elastic restoring force of the elastic arm portion 132c. Therefore, the gear tooth portion 132b can be meshed with the next pinion tooth.

Next, another embodiment of the present invention will be described with reference to the drawings. In this embodiment, the same members as those in the above-described embodiment are designated by the same reference numerals, and the description thereof will be omitted. Therefore, here, the points different from the above-described embodiment will be mainly described.

21 to 24 show one side of the thermal printer according to another embodiment of the present invention. Specifically, FIG. 21 is a view showing a thermal printer according to another embodiment of the present invention, and is a side view seen from the direction of arrow A shown in FIG. FIG. 22 is a side view showing a state in which the operating lever is removed from the state shown in FIG. FIG. 23 is a perspective view of each mechanism shown in FIG. FIG. 24 is a perspective view showing a state in which the operation lever is removed from the state shown in FIG. 23.

In addition, FIGS. 25 to 29 show the other side of the thermal printer according to another embodiment of the present invention. Specifically, FIG. 25 is a side view showing the periphery of the other lock arm in the thermal printer according to another embodiment of the present invention. FIG. 26 is a side view showing a state in which the operating lever is removed from the state shown in FIG. 25. FIG. 27 is a perspective view of each mechanism shown in FIG. 25. FIG. 28 is a perspective view showing a state in which the operation lever is removed from the state shown in FIG. 27. FIG. 29 is an enlarged view of a main part of the lock arm shown in FIG. 25.

As shown in FIGS. 21 to 24, a surrounding wall 170 is erected on one side wall portion 60 of the head frame 20 so as to surround the periphery excluding the meshing portion of the drive intermediate vehicle 76. On the other hand, although not shown, a shaft portion matching the shape of the surrounding wall 170 is formed on the inner surface of the gear cover 22 attached to the side wall portion 60 at a position corresponding to the surrounding wall 170. Thereby, the accuracy of positioning when the gear cover 22 is attached to the side wall portion 60 can be improved.

Further, the lock claw portion 145A of the pair of lock arms 140A and 150A according to the present embodiment has a shape different from that of the lock claw portion 145 of the lock arms 140 and 150 of the above-described embodiment. As shown in FIG. 29, the lock claw portion 145A has a linear detachment prevention surface 148A that prevents the platen bearing 51 from detaching from the accommodating groove 62 through the opening 62a in the locked state. The line L1 passing from the rotation center O2 of the lock arm 150A to the center of the platen bearing 51 and the detachment prevention surface 148A (S1) intersect vertically. The characteristics of the shape of the lock claw portion 145A are the same for the lock arm 140A.

As described above, in the platen lock mechanism 30 according to the present embodiment, the line from the rotation center of the lock arms 140A and 150A to the center O2 of the platen bearing 51 and the lock claw portion 145A of the lock arms 140A and 150A are formed. The structure is such that the bearing holding surface S1 is perpendicular to the bearing holding surface S1. As a result, even if the platen roller 45 is pulled away from the accommodating groove 62 by an external force in the locked state, the force for moving the lock arms 140A and 150A in the releasing direction (that is, the direction away from the platen bearing 51) is applied. Since it does not occur, it is possible to prevent the platen roller 45 from coming off.

Further, the left and right side wall portions 60 and 61 according to the present embodiment include platen support springs 180 and 190 composed of wire springs and the like. The platen support springs 180 and 190 are urging members that assist in holding the platen bearing 51 in the accommodating groove 62.

As shown in FIGS. 21 to 24, the platen support spring 180 is arranged between one side wall portion 60 and the lock arm 140A. A mountain-shaped bearing pressing portion 181 that presses the platen bearing 51 in the accommodating groove 62 in a direction that does not disengage is formed on one end side of the platen support spring 180. The other end side of the platen support spring 180 is bent around the connecting shaft portion 141, and the other end portion 182 is locked to the side wall portion 60 via a locking portion 171 formed on the side wall portion 60.

As shown in FIGS. 25 to 29, the platen support spring 190 is arranged between the other side wall portion 61 and the lock arm 150A. A mountain-shaped bearing pressing portion 191 that presses the platen bearing 51 in the accommodating groove 62 in a direction that does not disengage is formed on one end side of the platen support spring 190. The other end side of the platen support spring 190 is bent around the connecting shaft portion 141, and the other end portion 192 is locked to the side wall portion 61 via a locking hole 172 formed in the side wall portion 61.

According to the platen support springs 180 and 190 configured as described above, the bearing pressing portions 181 and 191 constantly urge the platen bearing 51 in the accommodating groove 62 toward the groove bottom portion 62b to hold the platen roller 45. Is assisting. As a result, even if there is a gap between the release prevention surfaces 148A of the lock arms 140A and 150A and the platen bearing 51 in the locked state, the backlash due to the gap can be absorbed and the platen bearing 51 can be held. As a result, it is possible to allow a margin for the design intersection of the lock arms 140A and 150A described above, the smooth swing of the lock arms 140A and 150A, and the reliable prevention of the platen bearing 51 by the detachment prevention surface 148A described above. Is feasible.
Further, since the platen support springs 180 and 190 bearing pressing portions 181 are formed in a chevron shape, when the platen roller 45 is disengaged, the disengagement operation is not unnecessarily hindered.

Next, a modification of another embodiment of the present invention will be described with reference to the drawings. In this modification, the same members as those in the above-described embodiment are designated by the same reference numerals, the description thereof will be omitted, and the points different from those in the above-described embodiment will be mainly described. Specifically, as the operating lever 28 moves from the locking position P3 toward the unlocking position P5, the platen support spring 180 on the operating lever 28 side swings in the direction of releasing the holding of the platen bearing 51. Then, it will be described that the platen bearing 51 is allowed to be detached from the inside of the accommodating groove 62 through the opening 62a.

FIG. 30 is a view showing a thermal printer according to a modified example of another embodiment of the present invention, and is a perspective view of a main part of a lock arm peripheral portion as viewed from the inner side surface. In FIG. 30, some parts are omitted in order to make it easier to see a configuration different from the above-described embodiment, but these omitted parts actually exist in the same manner as in the above-described embodiment.

As shown in FIG. 30, a boss-shaped protrusion 96 is formed on the inner surface of the swing plate 90. When the swing plate 90 swings, one end portion 183 of the platen support spring 180 comes into contact with the protrusion 96. Therefore, when the swing plate 90 swings by the pushing operation of the operating lever 28, the one end portion 183 of the platen support spring 180 and the bearing pressing portion 181 are pushed down to the opposite side of the platen bearing 51 in conjunction with the swing. This series of operations will be described with reference to FIGS. 31 to 33. Although some of these omitted parts are omitted in FIGS. 31 to 33 in order to make it easier to see the configuration different from the above-described embodiment, these omitted parts are actually the same as those in the above-described embodiment. Existing.

FIG. 31A is a side view of a main part of the operating lever 28 as viewed from the outer surface, showing a first stage (locked state) in a modified example of another embodiment of the present invention. FIG. 31B is a side view of a main part of the first stage (locked state) shown in FIG. 31A as viewed from the inner surface of the operating lever 28. FIG. 32A is a side view of a main part showing a second stage (intermediate state) in which the operation lever is pushed down from the state shown in FIG. 31A. FIG. 32B is a side view of a main part of the second stage (intermediate state) shown in FIG. 32A as viewed from the inner surface of the operating lever. FIG. 33A is a side view of a main part showing a third stage (unlocked state) in which the operating lever is pushed down from the state shown in FIG. 32A. FIG. 33B is a side view of a main part of the third stage (unlocked state) shown in FIG. 33A as viewed from the inner surface of the operating lever.

As shown in FIG. 31A, in the first stage (locked state), the engaging pin 95 formed on the second plate portion 93 of the swing plate 90 is the push-up cam 113 formed on the lever plate 110 of the operating lever 28. Is not in contact with. Further, as shown in FIG. 31B, the protrusion 96 of the swing plate 90 is not in contact with one end 183 of the platen support spring 180. Therefore, in this first stage (locked state), the bearing pressing portion 181 of the platen support spring 180 urges the platen bearing 51 in the accommodating groove 62 toward the groove bottom portion 62b to assist the holding of the platen roller 45. doing

As shown in FIG. 32A, in the second stage (intermediate state), the engaging pin 95 of the swing plate 90 and the pushing cam 113 of the operating lever 28 come into contact with each other by the pushing operation of the operating lever 28. Then, when the operating lever 28 is further pushed down, the swing plate 90 swings in the direction of arrow X in FIG. 32B around the pinion support shaft 81 inserted through the insertion hole 91. As shown in FIG. 32B, as the swing plate 90 swings, the protrusion 96 and one end 183 of the platen support spring 180 come into contact with each other, and the one end 183 side of the platen support spring 180 is in a direction away from the platen bearing 51. Is pushed down. As a result, the bearing pressing portion 181 of the platen support spring 180 retracts in the direction away from the platen bearing 51 in the accommodating groove 62, and the detachment path of the platen bearing 51 is opened.

As shown in FIG. 33A, in the third stage (unlocked state), the operating lever 28 is further pushed down from the states shown in FIGS. 32A and 32B, so that the lock arm 140A swings in the direction of retracting from the accommodating groove 62. At the same time, the push-up arm 147 forcibly pushes up the platen bearing 51 toward the opening 62a. At this time, since the platen support spring 180 that assisted the holding of the platen roller 45 in the locked state has already retracted from the accommodating groove 62 in the second stage (intermediate state) described above, the platen bearing in the accommodating groove 62. The 51 can be smoothly detached through the opening 62a.

As described above, according to the present modification, by providing the platen support spring 180 that assists the holding of the platen roller 45, there is a gap between the release prevention surface 148A of the lock arm 140A and the platen bearing 51 in the locked state. Even if there is, the platen bearing 51 can be held by absorbing the backlash due to the gap. Further, when the lock is released, the platen support spring 180 releases the holding of the platen bearing 51 and swings in the direction of retracting from the accommodating groove 62 before the push-up arm 147 pushes up the platen bearing 51, so that the platen is smooth. The release of the roller 45 can be realized. As a result, it is possible to reduce the pressing force of the operating lever 28 required to open the platen roller 45, and it is possible to improve the operability.

Although the embodiments of the present invention have been described above, these embodiments are presented as examples and are not intended to limit the scope of the invention. The embodiment can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the gist of the invention. The embodiments and modifications thereof include, for example, those that can be easily assumed by those skilled in the art, those that are substantially the same, those that have an equal range, and the like.

For example, in the above embodiment, an example in which the fixed blade 46 is provided on the printer cover 3 (specifically, the platen unit 6) and the movable blade 26 is provided on the casing 2 (specifically, the head unit 5) has been described. It is not limited to this case. For example, the fixed blade 46 may be provided on the casing 2 side, and the movable blade 26 may be provided on the printer cover 3 side.
However, as in the above embodiment, by providing the fixed blade 46 on the printer cover 3, it is not necessary to provide the drive mechanism 27 for driving the movable blade 26 on the printer cover 3, so that the weight of the printer cover 3 can be reduced. This makes it possible to ensure good opening and closing operability of the printer cover 3.

Further, in the above embodiment, an example in which the fixed blade 46 is held in a fixed state and the movable blade 26 is returned to the standby position P2 by the operating lever 28 to remove the paper jam has been described, but the present invention is limited to this case. is not it. For example, when the movable blade 26 is returned to the standby position P2 by the operating lever 28, the fixed blade 46 may be configured to be separated from the movable blade 26. In this case, for example, the operation of separating the fixed blade 46 from the movable blade 26 may be configured so that it can be operated by the operation lever 28.

Further, in the above embodiment, an example in which the operation lever 28 is interlocked with the rotational operation of the operation lever 19 provided on the casing 2 has been described, but the present invention is not limited to this case. For example, the tip of the operating lever 28 may be exposed to the outside of the casing 2 so that the operating lever 28 can be directly operated from the outside of the casing 2.

Further, in the above embodiment, an example in which the acceleration mechanism 136 is composed of the sun gear 133, the planetary gear 134, and the internal gear 135 has been described, but for example, the acceleration mechanism 136 may have another configuration.
Further, in the above embodiment, the case where the return mechanism 29 is provided has been described as an example, but the return mechanism 29 is not essential and may not be provided. Further, even when the return mechanism 29 is provided, another configuration may be adopted.

Further, in the above embodiment, the pair of lock arms 140 and 150 are used to hold both of the pair of platen bearings 51, but the present invention is not limited to this case, and one lock arm is used. It may be configured to hold down at least one platen bearing 51.

P ... Recording paper P1 ... Cutting position P2 ... Standby position P3 ... Lock position P5 ... Unlock position O2 ... Shaking axis 1 ... Thermal printer 2 ... Casing (printer body)
3 ... Printer cover 4 ... Printing unit 5 ... Head unit 6 ... Platen unit 16 ... Recording paper storage 25 ... Thermal head 26 ... Movable blade 27 ... Drive mechanism 28 ... Operation lever 29 ... Return mechanism 30 ... Platen lock mechanism 45 ... Platen Roller 46 ... Fixed blade 51 ... Platen bearing 62 ... Accommodating groove 62a ... Open port 62b ... Groove bottom 63 ... Guide protrusion 71 ... Drive rack 90 ... Swing plate 96 ... Protrusion 130 ... Return rack 130a, 130b ... Rack teeth 131 ... Return Pinion 132 ... Return gear 133 ... Sun gear 134 ... Planetary gear 135 ... Internal gear 140, 140A, 150, 150A ... Lock arm 141 ... Connecting shaft 145, 145A ... Lock claw 147 ... Push-up arm 148A ... Detachment prevention surface 160 ... Third urging member (urging member)
180, 190 ... Platen support spring 183 ... One end

Claims (12)

A head unit with a thermal head that prints on recording paper,
A platen roller that feeds the recording paper, and a platen unit that has a pair of platen bearings that rotatably support both ends of the platen roller and are separably combined with the head unit.
An operation lever that can move around the rotation axis between a lock position that locks the platen unit with respect to the head unit and an unlock position that unlocks the platen unit with respect to the head unit.
A platen lock mechanism having a lock arm capable of swinging around a swing axis parallel to the platen roller and switching between a locked state for locking the platen roller and an unlocked state for releasing the lock.
An urging member that urges the lock arm around the swing axis so as to maintain the locked state is provided.
A pair of the platen bearings can be fitted into the head unit through an opening, and the platen bearings are housed in contact with the groove bottom when the operating lever is located at the lock position. A pair of accommodating grooves are formed
The lock arm presses at least one of the pair of platen bearings accommodated in the accommodating groove from the opening side when the operating lever is located at the locked position, and the operating lever presses the operating lever. As it moves from the lock position toward the unlock position side, it swings around the swing axis to allow the platen bearing to be detached from the accommodating groove through the opening.
The lock arm is formed with a push-up arm that pushes up the platen bearing from the groove bottom toward the opening side as the operating lever moves from the lock position to the unlock position. Being done
The urging member is a printing unit characterized in that the lock arm is urged toward the platen unit side. In the printing unit according to claim 1,
The lock arm swings around the swing axis from the platen unit side toward the head unit side as the operation lever moves from the lock position toward the unlock position side. , A printing unit that allows the platen bearing to be detached from the accommodation groove through the opening. In the printing unit according to claim 1 or 2.
The push-up arm is a printing unit that is in non-contact with the platen bearing when the operating lever is located at the locked position. In the printing unit according to any one of claims 1 to 3,
An inclined guide projection is formed on the inner surface of the accommodating groove so that the opening width is narrowed from the opening side toward the groove bottom side and guides the platen bearing toward the groove bottom portion. ,
The push-up arm is a printing unit that pushes up the platen bearing so that the roller center of the platen roller moves toward the opening side of the apex of the guide protrusion. In the printing unit according to any one of claims 1 to 4.
The lock arms are arranged on both sides of the platen roller, and are provided in pairs corresponding to the pair of platen bearings.
The platen lock mechanism is a printing unit including a connecting shaft portion extending along the swing axis and connecting the pair of lock arms to each other. In the printing unit according to any one of claims 1 to 5,
A fixed blade provided on one of the head unit and the platen unit,
A movable blade provided on the other of the head unit and the platen unit and movable relative to the fixed blade,
It has a drive rack connected to the movable blade, and includes a drive mechanism for moving the movable blade between a standby position away from the fixed blade and a cutting position on the fixed blade. , Printing unit. In the printing unit according to claim 6,
In a state where the movable blade is stopped at the cutting position, the platen lock mechanism uses the operating force associated with the operation of the operation lever from the lock position to the unlock position to cause the platen roller to move the platen roller. A printing unit including a return mechanism for moving the movable blade from the cutting position to the standby position before switching to the unlocked state. In the printing unit according to claim 7,
The return mechanism
The return rack formed on the drive rack and
A return pinion that meshes with the rack teeth of the return rack,
A return gear and a sun gear that are rotatably supported around the rotation axis while being arranged coaxially with the rotation axis of the operation lever.
A planetary gear that meshes with the sun gear and revolves as the operating lever moves.
With an internal gear that meshes with the planetary gear,
The return gear is a printing unit capable of meshing with the return pinion. In the printing unit according to claim 8.
The rack teeth mesh with the return pinion when the movable blade is in the cutting position, and are disengaged with the return pinion when the movable blade is in the standby position. A printing unit formed on the opposite side of the cutting edge of the movable blade. In the printing unit according to any one of claims 1 to 9.
The lock arm has a linear detachment prevention surface that prevents the platen bearing from detaching from the accommodating groove through the opening in the locked state.
A printing unit in which a line passing from the center of rotation of the lock arm to the center of the platen bearing and the detachment prevention surface intersect vertically. In the printing unit according to any one of claims 1 to 9.
A platen support spring is provided to assist the platen bearing in being held in the accommodation groove.
The platen support spring releases the holding of the platen bearing before the push-up arm pushes up the platen bearing as the operating lever moves from the lock position toward the unlock position side. A printing unit that moves in the direction of the platen bearing and allows the platen bearing to be detached from the accommodating groove through the opening. The printing unit according to any one of claims 1 to 11.
A printer body having a recording paper storage unit for accommodating the recording paper, and to which one of the head unit and the platen unit is attached.
A thermal printer comprising a printer cover rotatably connected to the printer body and to which the other of the head unit and the platen unit is attached.

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