Patent Description:
Patent Literature <NUM> discloses a thermal transfer type printing device in which a ribbon cassette supporting an ink ribbon is attached to and detached from a printing device main body. Two locating guide shafts and a slider operation unit are provided on a cassette base of the ribbon cassette. The two locating guide shafts are provided at both left and right ends of the cassette base, and extend parallel to an attachment and detachment direction of the ribbon cassette. The slider operation unit is provided to be movable in a left-right direction. Inside the cassette base, an interlocking bar is provided to be movable in the left-right direction in conjunction with the slider operation unit, and locking claws are respectively provided at both left and right end portions of the interlocking bar.

When the ribbon cassette is mounted to the printing device main body, the two locating guide shafts are respectively inserted and fitted into two positioning guide holes provided in the printing device main body. After the ribbon cassette is mounted, the two locking claws move in the left-right direction in conjunction with the slider operation unit via the interlocking bar by an operation of the slider operation unit, so that the two locking claws are respectively locked to two locked portions provided on a printing device main body side, and a mounted state is locked.

In the printing device described in Patent Literature <NUM>, a guide mechanism including the locating guide shafts and the positioning guide holes, and a locking mechanism including the locking claws and the locked portions are provided at different positions independently of each other. Therefore, a problem arises that a space in the device is narrow.

An object of the present invention is to provide a printing device in which a wide space in the device can be used.

A printing device of claim <NUM> includes: a main body having a head support surface on which a thermal head is supported; and a cassette including a plate-shaped cassette base, a supply roll shaft, and a winding roll shaft, and detachably attached to the head support surface of the main body along an axis direction of the supply roll shaft and the winding roll shaft, the supply roll shaft rotatably supporting a ribbon supply roll and being provided on one side, in a predetermined direction, of a facing surface of the cassette base facing the head support surface, and the winding roll shaft rotatably supporting a ribbon winding roll and being provided on an other side, in the predetermined direction, of the facing surface, in which the printing device is configured to perform printing by transferring ink of an ink ribbon onto a print medium due to heating of the thermal head, and the ink ribbon is fed out from the ribbon supply roll and wound around the ribbon winding roll through the thermal head, and in which the printing device further includes: a guided portion provided on the facing surface of the cassette base; a guide portion provided at a position facing the guided portion on the head support surface of the main body, and configured to guide and locate the guided portion to a predetermined position on a side of the head support surface along the axis direction; a lock unit provided in the guided portion and configured to lock the guided portion to the guide portion in a state where the guided portion is located at the predetermined position by the guide portion; and a release unit configured to release locking performed by the lock unit. According to the printing device according to the aspect, since the lock unit is provided at the guide portion provided on the head support surface of the main body, the guide portion and the lock unit can be provided at the same position. Therefore, the printing device can effectively use a limited space in the printing device as compared with a configuration in which the guide portion and the lock unit are provided at different positions. Since the guided portion can be locked to the guide portion in the state where the guided portion is guided and located to the predetermined position by the guide portion, guiding and locking operations of the guided portion can be performed by a series of actions. As a result, the printing device can improve usability. The "predetermined position" means a predetermined position of the guided portion with respect to the guide portion in a state where the cassette is normally mounted to the main body in an attachment and detachment direction of the cassette.

The guided portion of the printing device of claim <NUM> may be provided between the supply roll shaft and the winding roll shaft in the predetermined direction on the facing surface of the cassette base, and may be provided, in a state where the cassette is mounted, at a location on a side opposite to the thermal head with respect to the supply roll shaft in an orthogonal direction that is orthogonal to the predetermined direction and the axis direction. Therefore, the cassette base is supported in a balanced manner in the predetermined direction with respect to the head support surface of the main body. A space between the supply roll shaft and the winding roll shaft is limited by a thickness of each of the ribbon supply roll and the ribbon winding roll, but the limited space in the printing device can be more effectively used by providing the guided portion in a dead space on the side opposite to the thermal head with respect to the supply roll shaft in the orthogonal direction.

The printing device of claim <NUM> may further include a grip portion provided on an outer surface of the cassette base on a side opposite to the facing surface, and configured to be gripped by a user, and the release unit may be provided in the grip portion. In the printing device according to the aspect, since the release unit is provided in the grip portion, the user can perform a release operation while gripping the grip portion. As a result, the aspect can provide the printing device having high usability.

The guided portion of the printing device of claim <NUM> may include a rod-shaped shaft extending from the facing surface toward a side of the head support surface in parallel with the axis direction, the guide portion may include a cylindrical guide body extending from the head support surface toward a side of the facing surface in parallel with the axis direction, and configured to guide and locate the shaft to the predetermined position by inserting the shaft inside the cylindrical guide body, the lock unit may include: an engagement portion provided to be cable of protruding from an opening portion from an inner side toward an outer side of the shaft in a radial direction, and being engageable with an engaged hole through the opening portion in a state where the shaft is guided to the predetermined position by the cylindrical guide body, the opening portion being provided on an outer peripheral surface of the shaft, and the engaged hole is provided in an outer peripheral surface of the cylindrical guide body, and the release unit may be provided in the shaft, and may be configured to move the engagement portion to the inner side in the radial direction to disengage the engagement portion from the engaged hole. According to the printing device according to the aspect, the shaft is automatically guided to the predetermined position by inserting the shaft into the cylindrical guide body. The engagement portion engages with the engaged hole in a state where the shaft is guided to the predetermined position, so that the shaft is locked to the cylindrical guide body. Guiding and locking can be simultaneously performed by one action of inserting the shaft into the cylindrical guide body, so that operability is improved. The locking can be easily released by disengaging the engagement portion from the engaged hole.

The shaft of the printing device of claim <NUM> may include: a cylindrical holder fixed to the facing surface and extending in parallel with the axis direction toward the side of the head support surface; and a cylindrical guide shaft coaxially disposed in the holder and extending from a tip end portion of the holder toward the side of the head support surface, the tip end portion facing the side of the head support surface, the release unit may include: a rod-shaped center shaft disposed in the holder and the guide shaft and provided to be movable along a length direction of the holder and the guide shaft, the lock unit may include: a first biasing member configured to constantly bias the center shaft toward a side of the cassette base, the engagement portion may be a spherical body, and may be provided between the guide shaft and the center shaft, the spherical body being disposed to be slidable on an outer peripheral surface of the center shaft, and a part of the spherical body being exposed from the opening portion to engage with the engaged hole in a first state where the spherical body is in contact with the outer peripheral surface of the center shaft moved toward the side of the cassette base by the first biasing member, a recessed portion recessed toward an inner side of the center shaft in a radial direction may be provided on the outer peripheral surface of the center shaft at a position closer to the side of the cassette base than a position with which the part of the spherical body is in contact in the first state, and the release unit may be configured to shift from the first state to a second state where the spherical body is in contact with the recessed portion and to disengage the spherical body from the engaged hole by moving the center shaft toward the side of the head support surface against a biasing force of the first biasing member and disposing the recessed portion at a position of the spherical body, to release the locking. According to the printing device according to the aspect, by moving the center shaft within the guide shaft and causing the center shaft to be the first state, a part of the spherical body can be exposed from the opening portion and can engage with the engaged hole, and the shaft can be locked to the cylindrical guide body. By switching the center shaft from the first state to the second state, the spherical body moves inward from the opening portion to be disengaged from the engaged hole, so that the locking can be easily released.

The guide shaft of the printing device of claim <NUM> may be supported in the holder to be rotatable about an axis, and the printing device may include: a second biasing member provided in the holder and configured to constantly bias the guide shaft in one direction about the axis; and a guide groove provided on the outer peripheral surface of the cylindrical guide body, extending from one end portion of the cylindrical guide body toward the engaged hole to be inclined in a direction opposite to the one direction about the axis, and configured to guide the part of the spherical body exposed from the opening portion from the one end portion to the engaged hole, the one end portion facing the side of the cassette base. The shaft is inserted along an inside of the cylindrical guide body, and a part of the spherical body exposed from the opening portion of the shaft is pushed toward the side of the head support surface along the guide groove. At this time, since the spherical body is guided along the guide groove in a direction opposite to a biasing direction of the second biasing member, the guide shaft rotates in the same direction together with the spherical body. When the spherical body is guided to the engaged hole, the guide shaft is biased in the one direction about the axis and pulled back by the second biasing member, and the spherical body engages with the engaged hole to perform the locking. As a result, the guiding and the locking can be performed by only one action of inserting the shaft into the cylindrical guide body.

The second biasing member of the printing device of claim <NUM> may be a torsion coil spring. As a result, a biasing force can be easily applied to the guide shaft in the one direction about the axis.

The release unit of the printing device of claim <NUM> may include an operation unit fixed to one end portion of the center shaft located on a side of the holder, and configured to push the center shaft toward the side of the head support surface. Since the user can release the locking only by pushing the operation unit toward the side of the head support surface, the release operation can be performed more easily. Therefore, the printing device can improve the usability.

The shaft of the printing device of claim <NUM> may include: a cylindrical holder fixed to the facing surface and extending in parallel with the axis direction toward the side of the head support surface; and a cylindrical guide shaft coaxially disposed in the holder and extending from a tip end portion of the holder toward the side of the head support surface, the tip end portion facing the side of the head support surface the release unit may include: a rod-shaped first shaft and a rod-shaped second shaft disposed in the holder and the guide shaft, and coaxially provided to be movable along a length direction of the holder and the guide shaft, the cylindrical guide body may include an abutment portion configured to, in a state where the cassette is mounted to the main body, abut against the second shaft to restrict the guide shaft from moving toward the side of the head support surface in the length direction of the guide shaft, the lock unit may include: a third biasing member disposed between the first shaft and the second shaft, and configured to bias the first shaft toward a side of the cassette base in a state where the cassette is mounted to the main body, the engagement portion may be a spherical body, and may be provided between the first shaft and the center shaft, the spherical body being disposed to be slidable on an outer peripheral surface of the first shaft, and a part of the spherical body being exposed from the opening portion to engage with the engaged hole in a locked state where the spherical body is in contact with the outer peripheral surface of the first shaft moved toward the side of the cassette base by the third biasing member, a recessed portion recessed toward an inner side of the first shaft in a radial direction may be provided on the outer peripheral surface of the first shaft at a position closer to the side of the cassette base than a position with which the part of the spherical body is in contact in the locked state, and the release unit may be configured to shift from the locked state to a released state where the spherical body is in contact with the recessed portion and to disengage the spherical body from the engaged hole by moving the first shaft toward the side of the head support surface against a biasing force of the third biasing member and disposing the recessed portion at a position of the spherical body, to release the locking. According to the printing device according to the aspect, by moving the first shaft within the guide shaft and causing the first shaft to be the locked state, a part of the spherical body can be exposed from the opening portion and can engage with the engaged hole, and the shaft can be locked to the cylindrical guide body. By switching the first shaft from the locked state to the released state, the spherical body moves inward from the opening portion to be disengaged from the engaged hole, so that the locking can be easily released.

An embodiment of the present invention will be described with reference to the drawings. In the following description, left and right, front and rear, and up and down indicated by arrows in the drawings are used. A printing device <NUM> shown in <FIG> can print desired characters and graphics by allowing a belt-shaped packaging material (not shown) fed out from a packaging material supply roll (not shown) to pass through a lower portion from left to right.

A configuration of the printing device <NUM> will be described. As shown in <FIG>, the printing device <NUM> is formed in a substantially rectangular parallelepiped shape, and includes an outer decorative plate <NUM>. The outer decorative plate <NUM> covers an outer peripheral surface of the printing device <NUM> around an axis in a front-rear direction, and can be attached to and detached from the printing device <NUM>. In <FIG> and <FIG>, the outer decorative plate <NUM> is not shown. The printing device <NUM> includes a main body <NUM> and a cassette <NUM> which are separable from each other in the front-rear direction. The outer decorative plate <NUM> can be mounted on a side of the main body <NUM>, and the cassette <NUM> is inserted inside the outer decorative plate <NUM>. As shown in <FIG>, the cassette <NUM> can be attached to and detached from the main body <NUM> by being inserted and pulled out along an axis direction (front-rear direction) of a supply roll shaft <NUM> and a winding roll shaft <NUM> which are provided on a side of the cassette <NUM> and which will be described later.

A structure of the cassette <NUM> will be described. As shown in <FIG> and <FIG>, the cassette <NUM> is disposed on a front side of the printing device <NUM>, and includes a cassette base <NUM>, a handle <NUM>, the supply roll shaft <NUM>, the winding roll shaft <NUM>, two guide rollers <NUM> and <NUM>, a locating shaft <NUM>, and the like.

The cassette base <NUM> is formed in a substantially rectangular shape in a front view. The handle <NUM> is provided on a side of a front surface 41A of the cassette base <NUM>, and includes a grip portion <NUM>, an upper support portion <NUM>, and a lower support portion <NUM>. The grip portion <NUM> is provided at a position spaced forward from a front surface 41A to extend in an up-down direction, and is gripped by a user. The upper support portion <NUM> bridges between a central portion of an upper end portion of the cassette base <NUM> and an upper end portion of the grip portion <NUM>. The lower support portion <NUM> bridges between a central portion of a lower end portion of the cassette base <NUM> and a lower end portion of the grip portion <NUM>. As a result, the handle <NUM> is provided to bridge, in the up-down direction, between the respective central portions of the upper end portion and the lower end portion of the cassette base <NUM>. The handle <NUM> is gripped by the user when the cassette <NUM> is to be attached to and detached from the main body <NUM>. A release button <NUM> is provided in an upper portion of a front surface of the grip portion <NUM>. The release button <NUM> is pressed down from a front by the user in order to release locking to the main body <NUM> by the locating shaft <NUM> to be described later.

As shown in <FIG>, the supply roll shaft <NUM> and the winding roll shaft <NUM> are provided side by side in a left-right direction on a back surface 41B of the cassette base <NUM> and above a central position in the up-down direction. The supply roll shaft <NUM> is disposed on a left side, and the winding roll shaft <NUM> is disposed on a right side. The supply roll shaft <NUM> and the winding roll shaft <NUM> are provided to extend rearward from the back surface 41B, and are each provided to be rotatable about a central axis. One end of a series of belt-shaped ink ribbons (not shown) is fixed to the supply roll shaft <NUM> in advance and the ink ribbons are wound around the supply roll shaft <NUM> in advance. The other end of the ink ribbons is fixed to the winding roll shaft <NUM>, so that the ink ribbons fed out from the supply roll shaft <NUM> are wound into a roll shape.

The guide roller <NUM> is provided at a lower left corner portion of the back surface 41B. The guide roller <NUM> is provided at a lower right corner portion of the back surface 41B. The guide rollers <NUM> and <NUM> are provided to extend rearward from the back surface 41B, and are each provided to be rotatable about a central axis. The ink ribbons fed out from the supply roll shaft <NUM> are finally guided to the winding roll shaft <NUM> through a conveyance path that is bent by abutting against outer peripheral surfaces of the two guide rollers <NUM> and <NUM>.

The locating shaft <NUM> is provided in a central upper portion, between the supply roll shaft <NUM> and the winding roll shaft <NUM>, of the back surface 41B. The position is in a (central in an example) region between the supply roll shaft <NUM> and the winding roll shaft <NUM> in the left-right direction, and is located substantially at an upper end of the cassette base <NUM> in the up-down direction. The position is a position that does not interfere with feeding out and winding of the ink ribbons regardless of an used amount of the ink ribbons as described later, and does not hinder an operation of a thermal head <NUM> since the position is located, even when the cassette <NUM> is mounted, on a side opposite to a lower side where the thermal head <NUM> is located. A through hole <NUM> is provided at a position on the back surface 41B where the locating shaft <NUM> is provided (see <FIG>). The through hole <NUM> penetrates the cassette base <NUM> in the front-rear direction, and communicates in the front-rear direction with an insertion hole <NUM> (see <FIG>) provided inside the upper support portion <NUM> of the handle <NUM>. The insertion hole <NUM> extends in the front-rear direction, and a front end portion thereof is open at the upper portion of the front surface of the grip portion <NUM> (see <FIG>).

The locating shaft <NUM> is formed in a rod shape having a substantially circular transverse cross section, and is inserted into the insertion hole <NUM> and the through hole <NUM> in the front-rear direction. The locating shaft <NUM> protrudes and extends rearward from the back surface 41B of the cassette base <NUM>. The locating shaft <NUM> is inserted into a later-described cylindrical guide body <NUM> (see <FIG>) of the main body <NUM>, and is locked in a state of being located at a predetermined position. The release button <NUM> is fixed to a front end portion of the locating shaft <NUM>. The release button <NUM> protrudes forward from an opening in the upper portion of the front surface of the grip portion <NUM>. A specific structure of the locating shaft <NUM> will be described later.

A structure of the main body <NUM> will be described. <FIG> illustrates the main body <NUM> in a state where the outer decorative plate <NUM> is removed. As shown in <FIG>, the main body <NUM> includes a main body base <NUM>, a cover portion <NUM>, a supply roll bearing portion <NUM>, a winding roll bearing portion <NUM>, a bearing portion <NUM>, a support shaft <NUM>, the cylindrical guide body <NUM>, the thermal head <NUM>, a head driving unit <NUM>, a mechanism driving unit <NUM>, and the like. The main body base <NUM> is formed in a substantially rectangular shape in a front view, and a front surface 31A thereof faces the back surface 41B of the cassette base <NUM> in the state where the cassette <NUM> is mounted. The cover portion <NUM> is provided on a back surface side of the main body base <NUM>, and is formed in a substantially rectangular parallelepiped box shape. The cover portion <NUM> surrounds and protects the mechanism driving unit <NUM> which will be described later and which is provided on the back surface side of the main body base <NUM>.

The supply roll bearing portion <NUM> and the winding roll bearing portion <NUM> are provided at positions on the front surface 31A of the main body base <NUM> respectively corresponding to the supply roll shaft <NUM> and the winding roll shaft <NUM> of the cassette <NUM>. The supply roll bearing portion <NUM> supports the supply roll shaft <NUM> in a state where a tip end of the supply roll shaft <NUM> abuts on the supply roll bearing portion <NUM>, and transmits a rotational driving force to the supply roll shaft <NUM> so that a ribbon supply roll (not shown) can be wound therearound. The winding roll bearing portion <NUM> supports the winding roll shaft <NUM> in a state where a tip end of the winding roll shaft <NUM> abuts on the winding roll bearing portion <NUM>, and transmits a rotational driving force to the winding roll shaft <NUM> so that a ribbon winding roll (not shown) can be wound therearound.

The bearing portion <NUM> is provided at a position on the front surface 31A of the main body base <NUM> corresponding to the guide roller <NUM> of the cassette <NUM>. The bearing portion <NUM> rotatably supports the guide roller <NUM> by engaging with a tip end portion 45A of the guide roller <NUM>. The support shaft <NUM> is provided at a position on the front surface 31A of the main body base <NUM> corresponding to the guide roller <NUM> of the cassette <NUM>. The support shaft <NUM> is inserted into a central shaft hole of the guide roller <NUM> and rotatably supports the guide roller <NUM>.

The cylindrical guide body <NUM> is provided in a central upper portion, between the supply roll bearing portion <NUM> and the winding roll bearing portion <NUM>, of the front surface 31A, and is provided at a position corresponding to the locating shaft <NUM> of the cassette <NUM>. The cylindrical guide body <NUM> is formed in a substantially cylindrical shape extending forward from the front surface 31A, and the locating shaft <NUM> can be inserted into the cylindrical guide body <NUM> from a front. The cylindrical guide body <NUM> includes a pair of guide grooves <NUM> in an upper portion and a lower portion. Each of the guide grooves <NUM> sequentially includes an inclined portion <NUM>, a straight portion <NUM>, and an engaged hole <NUM> from a front side to a rear side. The inclined portion <NUM> is formed in a linear shape in a plan view, and the linear shape is inclined toward a rear right side with respect to an axis from a front end of the cylindrical guide body <NUM>. The straight portion <NUM> is formed in a linear shape extending rearward from a rear end of the inclined portion <NUM>, and is shorter than the inclined portion <NUM>. The engaged hole <NUM> is bent leftward from a rear end of the straight portion <NUM>, and is formed in a substantially rectangular shape in a plan view. A width of the guide groove <NUM> may be any width as long as balls <NUM> and <NUM>, which will be described later, of the locating shaft <NUM> can be guided.

The thermal head <NUM> includes a plurality of thermoelectric elements arranged in the front-rear direction. The head driving unit <NUM> is provided on a lower side of the front surface 31A, and supports the thermal head <NUM> such that the thermal head <NUM> can move in the left-right direction and the up-down direction. The mechanism driving unit <NUM> is provided on the back surface side of the main body base <NUM>, and includes a plurality of actuators such as various motors. The mechanism driving unit <NUM> respectively drives the supply roll bearing portion <NUM>, the winding roll bearing portion <NUM>, the head driving unit <NUM>, and the thermal head <NUM> based on control commands received from a controller (not shown). The controller may be provided in the printing device <NUM>, or may be provided in a terminal (not shown) that is connected to the printing device <NUM> to be able to communicate with the printing device <NUM> in a wired or wireless manner.

The structure of the locating shaft <NUM> will be described with reference to <FIG>. The locating shaft <NUM> includes a holder <NUM>, a guide shaft <NUM>, a fixing ring <NUM>, a cap <NUM>, a center shaft <NUM>, the release button <NUM>, the balls <NUM> and <NUM>, a cylindrical collar <NUM>, a release spring <NUM>, a lock spring <NUM>, and the like. The holder <NUM>, the guide shaft <NUM>, the fixing ring <NUM>, the cap <NUM>, the release button <NUM>, and the cylindrical collar <NUM> are each made of a resin, and the center shaft <NUM> and the balls <NUM> and <NUM> are each made of a metal, but materials are not limited to these material.

The holder <NUM> is formed in a short axis cylindrical shape extending in the left-right direction. A fixing flange <NUM> is provided on a right side of an outer peripheral surface of the holder <NUM>. The fixing flange <NUM> is formed in a substantially triangular shape in a right side view, and includes a pair of fixing holes <NUM> (see <FIG>). A front surface of the fixing flange <NUM> abuts on the back surface 41B of the cassette base <NUM>. The fixing flange <NUM> is fixed to the back surface 41B of the cassette base <NUM> by two screws <NUM> through the pair of fixing holes <NUM>.

The guide shaft <NUM> is formed in a long axis cylindrical shape extending in the front-rear direction, and is coaxially inserted and disposed inside the holder <NUM>. The guide shaft <NUM> includes a guide hole <NUM> therein. The guide hole <NUM> extends in the front-rear direction. The guide shaft <NUM> protrudes and extends rearward from a rear end portion of the holder <NUM>. A diameter-reduced portion <NUM> whose diameter is reduced toward an inner side in a radial direction is provided on an outer peripheral surface of the guide shaft <NUM> on a front end side. A locking ring <NUM> is fixed to a position on an outer peripheral surface of the guide shaft <NUM> close to a rear side of the diameter-reduced portion <NUM>. The locking ring <NUM> protrudes from the outer peripheral surface of the guide shaft <NUM> toward an outer side in the radial direction. The locking ring <NUM> abuts on an upper portion of a front end portion of the holder <NUM> from a front.

A through hole <NUM> is provided on the outer peripheral surface of the guide shaft <NUM> behind the locking ring <NUM>. The through hole <NUM> penetrates the guide shaft <NUM> in the up-down direction orthogonal to a length direction of the guide shaft <NUM>. A substantially columnar pin <NUM> is attachably and detachably inserted into and fixed to the through hole <NUM> from a lower portion. A stepped portion <NUM> is provided to be closer to a rear end side than a central portion of the guide shaft <NUM> in the length direction. The stepped portion <NUM> has a substantially cylindrical shape having a diameter reduced toward the inner side in the radial direction and having a predetermined length. A pair of upper and lower holes <NUM> and <NUM> are provided in the stepped portion <NUM>. The holes <NUM> and <NUM> are round holes and penetrate in the up-down direction. A diameter of each of the holes <NUM> and <NUM> may be any diameter as long as a respective one of the balls <NUM> and <NUM> to be described later can be inserted therethrough in the up-down direction.

The fixing ring <NUM> has substantially the same diameter as that of the holder <NUM>, and is formed in a short axis cylindrical shape extending in the left-right direction. The fixing ring <NUM> is mounted on an outer side of the guide shaft <NUM>, and is fixed to the guide shaft <NUM> by a fixing screw <NUM> in a state of abutting on the rear end portion of the holder <NUM>. As a result, the fixing ring <NUM> is integrated with the guide shaft <NUM>. The fixing ring <NUM> restricts forward movement of the guide shaft <NUM> by abutting on the rear end portion of the holder <NUM>. The locking ring <NUM> restricts rearward movement of the guide shaft <NUM> by abutting on the front end portion of the holder <NUM>. Therefore, the guide shaft <NUM> is located in the front-rear direction with respect to the holder <NUM>.

The cap <NUM> is formed in a substantially cylindrical shape extending in the front-rear direction. The cap <NUM> includes a guide hole <NUM> therein. The cap <NUM> is coaxially mounted to the rear end side of the guide shaft <NUM>. As a result, the guide hole <NUM> and the guide hole <NUM> of the guide shaft <NUM> coaxially communicate with each other.

The center shaft <NUM> is formed in a rod shape extending in the front-rear direction. The center shaft <NUM> is coaxially inserted and disposed inside the guide hole <NUM> of the guide shaft <NUM> and the guide hole <NUM> of the cap <NUM>, and is supported to be movable along the length direction of the guide shaft <NUM> and the cap <NUM>. A front end side of the center shaft <NUM> protrudes forward from the diameter-reduced portion <NUM> of the guide shaft <NUM>. A button fixing portion <NUM> is provided at a front end portion of the center shaft <NUM>. A recessed portion <NUM> whose diameter is reduced toward an inner side in the radial direction is provided on an outer peripheral surface of a substantially central portion of the center shaft <NUM> in the front-rear direction.

The release button <NUM> is formed in a substantially columnar shape having a short axis and extending in the front-rear direction, and is fixed to the button fixing portion <NUM>. A substantially ring-shaped groove portion <NUM> recessed forward is provided in a rear end surface of the release button <NUM>.

The balls <NUM> and <NUM> are disposed inside the holes <NUM> and <NUM> of the guide shaft <NUM>, respectively. The balls <NUM> and <NUM> are in contact with an outer peripheral surface of the center shaft <NUM> in the guide hole <NUM> of the guide shaft <NUM>, and slide on the outer peripheral surface of the center shaft <NUM> as the center shaft <NUM> moves.

The cylindrical collar <NUM> is formed in a short axis cylindrical shape extending in the front-rear direction, and is mounted on an outer peripheral surface of the stepped portion <NUM> of the guide shaft <NUM>. The cylindrical collar <NUM> is provided with a pair of upper and lower exposure holes <NUM> and <NUM>. The exposure holes <NUM> and <NUM> are provided at positions corresponding to the pair of upper and lower holes <NUM> and <NUM> of the guide shaft <NUM>. A diameter of each of the exposure holes <NUM> and <NUM> is smaller than the diameter of a respective one of the balls <NUM> and <NUM>. As a result, the cylindrical collar <NUM> can allow a part of each of the balls <NUM> and <NUM> to protrude outward from a respective one of the exposure holes <NUM> and <NUM>, and can prevent the balls <NUM> and <NUM> from falling out of the exposure holes <NUM> and <NUM> respectively.

The release spring <NUM> is a cylindrical compression coil spring extending in the front-rear direction, and is a push-back spring that performs pushing back in a reverse direction of an axial direction when a load is applied in the axial direction. The release spring <NUM> is mounted on the front end side of the center shaft <NUM>. A front end portion of the release spring <NUM> is inserted into the groove portion <NUM> of the release button <NUM> from a rear side, and abuts against a wall surface of the groove portion <NUM> on a back side. A rear end portion of the release spring <NUM> abuts against a front end portion of the guide shaft <NUM>. As a result, when the release button <NUM> is pressed rearward, the release spring <NUM> acts to push back the release button <NUM> forward in accordance with a pressing load.

The lock spring <NUM> is a torsion coil spring, and is mounted on an outer peripheral surface of the diameter-reduced portion <NUM> on the front end side of the guide shaft <NUM>. One end portion <NUM> of the lock spring <NUM> on a front end side is fixed to the diameter-reduced portion <NUM> of the guide shaft <NUM>. The other end portion <NUM> of the lock spring <NUM> on a rear end side is locked to a locked portion (not shown) provided on an inner peripheral surface of the insertion hole <NUM> in the upper support portion <NUM> of the handle <NUM>. The lock spring <NUM> is wound in a clockwise direction (clockwise) about an axis when viewed from the front end side. Therefore, when each of the guide shaft <NUM> and the cap <NUM> rotates in the clockwise direction (clockwise) about an axis with respect to the holder <NUM> when viewed from a front end side, since the lock spring <NUM> is wound up in the same direction as a winding direction, the lock spring <NUM> acts in a direction of pushing back each of the guide shaft <NUM> and the cap <NUM> in a counterclockwise direction (counterclockwise) about the center shaft <NUM> when viewed from the front end side.

Switching between a first state and a second state of the locating shaft <NUM> will be described with reference to <FIG> and <FIG>. The locating shaft <NUM> can be displaced between the first state and the second state by an operation of the release button <NUM>. The locating shaft <NUM> shown in <FIG> is in the first state. In the first state, the release spring <NUM> biases the release button <NUM> forward. As a result, inside the guide hole <NUM> of the guide shaft <NUM>, the center shaft <NUM> moves forward integrally with the release button <NUM>. At this time, a portion of the outer peripheral surface of the center shaft <NUM> behind the recessed portion <NUM> is located at positions of the balls <NUM> and <NUM>. Therefore, the balls <NUM> and <NUM> are pushed toward an outer side in the radial direction by the outer peripheral surface of the center shaft <NUM>, and a part of each of the balls <NUM> and <NUM> protrudes from a respective one of the exposure holes <NUM> and <NUM>.

In the first state shown in <FIG>, when the release button <NUM> is pushed rearward against a spring force of the release spring <NUM>, the center shaft <NUM> moves rearward inside the guide hole <NUM> of the guide shaft <NUM>. At this time, the balls <NUM> and <NUM> slide on the outer peripheral surface of the guide shaft <NUM>, and face a position of the recessed portion <NUM> of the center shaft <NUM>. Therefore, since the balls <NUM> and <NUM> are movable inward in the radial direction, the balls <NUM> and <NUM> respectively move inward from the exposure holes <NUM> and <NUM> by being pushed in from an outside, so that the locating shaft <NUM> is switched to the second state.

A method for inserting the locating shaft <NUM> into the cylindrical guide body <NUM> and locking the locating shaft <NUM> will be described. In order to mount the cassette <NUM> to the main body <NUM>, the user grips the handle <NUM> of the cassette <NUM> and disposes the cassette <NUM> on a front side of the main body <NUM>. The back surface 41B of the cassette base <NUM> of the cassette <NUM> faces the front surface 31A of the main body base <NUM> of the main body <NUM>. The locating shaft <NUM> on a side of the back surface 41B faces the cylindrical guide body <NUM> on a side of the front surface 31A.

As shown in <FIG>, the user inserts a tip end side of the locating shaft <NUM> into the cylindrical guide body <NUM>. Since the locating shaft <NUM> is in the first state, a part of the ball <NUM> protrudes upward from the upper exposure hole <NUM>, and a part of the ball <NUM> protrudes downward from the lower exposure hole <NUM>. The user inserts a part of the ball <NUM> protruding from the upper exposure hole <NUM> into a front end side of the upper guide groove <NUM> of the cylindrical guide body <NUM>. At the same time, the user inserts a part of the ball <NUM> protruding from the lower exposure hole <NUM> into a front end side of the lower guide groove <NUM> of the cylindrical guide body <NUM>.

The user moves the cassette <NUM> toward a side of the main body <NUM> in a state of gripping the handle <NUM>. As shown in <FIG> and <FIG>, as the locating shaft <NUM> is pushed toward a back side of the cylindrical guide body <NUM>, each of the balls <NUM> and <NUM> moves along the inclined portion <NUM> of the guide groove <NUM>. Each of the balls <NUM> and <NUM> moves along the inclined portion <NUM>, so that each of the balls <NUM> and <NUM> rotates in the clockwise direction (clockwise) about the center shaft <NUM> when viewed from a front end side. Accordingly, the guide shaft <NUM> and the cap <NUM> rotate in the clockwise direction (clockwise) about the center shaft <NUM> integrally with the balls <NUM> and <NUM> against a spring force of the lock spring <NUM> when viewed from the front end side.

As shown in <FIG>, when each of the balls <NUM> and <NUM> moves from the inclined portion <NUM> along the straight portion <NUM>, rotation of the guide shaft <NUM> and the cap <NUM> is stopped. When each of the balls <NUM> and <NUM> abuts against a rearmost end of the guide groove <NUM> from the straight portion <NUM>, rearward movement of the locating shaft <NUM> is restricted, so that the locating shaft <NUM> is located at the predetermined position with respect to the cylindrical guide body <NUM>. Due to the spring force of the lock spring <NUM>, the guide shaft <NUM> and the cap <NUM> are pushed back by rotating in the counterclockwise direction (counterclockwise) about the center shaft <NUM> when viewed from the front end side, and each of the balls <NUM> and <NUM> engages with the engaged hole <NUM> (see <FIG>). As a result, the locating shaft <NUM> is in a locked state of being locked to the cylindrical guide body <NUM>, and the cassette <NUM> is mounted to the main body <NUM>.

As described above, in the printing device <NUM>, guiding and locking of the locating shaft <NUM> can be simultaneously performed by only one action of inserting the locating shaft <NUM> into the cylindrical guide body <NUM>, so that operability can be improved. By disengaging each of the balls <NUM> and <NUM> from the engaged hole <NUM>, the locked state can be easily released.

A method for releasing the locking of the locating shaft <NUM> to pull out the locating shaft <NUM> from the cylindrical guide body <NUM> will be described. In a state shown in <FIG>, the user presses down the release button <NUM> with a thumb of a hand with which the handle <NUM> is gripped while gripping the handle <NUM> of the cassette <NUM>. Then, the center shaft <NUM> is pushed rearward, so that a positional relationship between the recessed portion <NUM> and the balls <NUM> and <NUM> changes, and the locating shaft <NUM> changes from the first state (see <FIG>) to the second state (see <FIG>). The user pulls out the locating shaft <NUM> from the cylindrical guide body <NUM> by pulling the handle <NUM> forward. At this time, since each of the balls <NUM> and <NUM> is pushed into an inside of the guide shaft <NUM> by an inner edge portion of a respective one of the exposure holes <NUM> and <NUM>, the locking to the cylindrical guide body <NUM> is released. As a result, the user can easily pull out the locating shaft <NUM> from the cylindrical guide body <NUM> (see <FIG>), and can easily remove the cassette <NUM> from the main body <NUM>.

As described above, the printing device <NUM> according to the present embodiment includes the main body <NUM> and the cassette <NUM>. The front surface 31A of the main body <NUM> supports the thermal head <NUM>. The cassette <NUM> includes the plate-shaped cassette base <NUM>, the supply roll shaft <NUM>, and the winding roll shaft <NUM>. The supply roll shaft <NUM> is provided on a left side of the back surface 41B of the cassette base <NUM> facing the front surface 31A, and rotatably supports the ribbon supply roll (not shown). The winding roll shaft <NUM> is provided on a right side of the back surface 41B, and rotatably supports the ribbon winding roll (not shown). The cassette <NUM> is attached to and detached from the front surface 31A of the main body <NUM> along the axis direction of the supply roll shaft <NUM> and the winding roll shaft <NUM>. The printing device <NUM> performs printing by transferring ink of the ink ribbon onto a print medium duet to heating of the thermal head <NUM>, and the ink ribbon is fed out from the ribbon supply roll and wound around the ribbon winding roll through the thermal head <NUM>.

The printing device <NUM> further includes the locating shaft <NUM>, the cylindrical guide body <NUM>, the balls <NUM> and <NUM>, the center shaft <NUM>, and the release button <NUM>. The locating shaft <NUM> is provided in the back surface 41B of the cassette base <NUM> of the cassette <NUM>. The cylindrical guide body <NUM> is provided at the position on the front surface 31A of the main body <NUM> facing the locating shaft <NUM>, and guides and locates the locating shaft <NUM> to the predetermined position on the side of the front surface 31A along the axis direction. The balls <NUM> and <NUM> are provided in the locating shaft <NUM>, and locks the locating shaft <NUM> to the cylindrical guide body <NUM> in a state where the locating shaft <NUM> is located at the predetermined position by the cylindrical guide body <NUM>. The release button <NUM> is pressed down by the user to release the locking. When the release button <NUM> is pressed down, the center shaft <NUM> is pushed in, the balls <NUM> and <NUM> can retract, and the locking is released.

As described above, in the printing device <NUM>, the balls <NUM> and <NUM> are provided in the cylindrical guide body <NUM> provided in the front surface 31A of the main body <NUM>, so that a limited space in the printing device <NUM> can be effectively used. Since the locating shaft <NUM> can be locked to the cylindrical guide body <NUM> in a state where the locating shaft <NUM> is guided and located to the predetermined position by the cylindrical guide body <NUM>, usability can be improved.

The locating shaft <NUM> is provided in the central upper portion, between the supply roll shaft <NUM> and the winding roll shaft <NUM>, of the back surface 41B of the cassette base <NUM>. Therefore, the cassette base <NUM> is supported in a balanced manner in the left-right direction with respect to the front surface 31A of the main body <NUM>. A space between the supply roll shaft <NUM> and the winding roll shaft <NUM> is limited by a thickness of each of the ribbon supply roll and the ribbon winding roll, but the limited space in the printing device <NUM> can be more effectively used by providing the locating shaft <NUM> in a dead space above the supply roll shaft <NUM> and the winding roll shaft <NUM>.

The cassette <NUM> includes the handle <NUM>. The handle <NUM> is provided on the front surface 41A of the cassette base <NUM>, and can be gripped by the user. Since the release button <NUM> is provided in the handle <NUM>, a release operation for the locking can be easily performed.

In the above description, the locating shaft <NUM> is an example of a "shaft" in the present invention. The exposure holes <NUM> and <NUM> are examples of an "opening portion" in the present invention. The balls <NUM> and <NUM> are examples of a "spherical body" in the present invention. The release spring <NUM> is an example of a "first biasing member" in the present invention, and the lock spring <NUM> is an example of a "second biasing member" in the present invention. The release button <NUM> is an example of an "operation unit" in the present invention. The front surface 31A of the main body base <NUM> of the main body <NUM> is an example of a "head support surface" in the present invention. The back surface 41B of the cassette base <NUM> of the cassette <NUM> is an example of a "facing surface" in the present invention.

Various modifications can be made to the present invention in addition to the above embodiment. For example, the printing device <NUM> according to the above embodiment performs printing by allowing the packaging material to pass through the lower portion from the left to the right, but may perform printing by allowing the packaging material to pass through the lower portion from the left to the right. A configuration of the head driving unit <NUM> for the thermal head <NUM> can also be freely changed.

The locating shaft <NUM> is provided in the central upper portion, between the supply roll shaft <NUM> and the winding roll shaft <NUM>, of the back surface 41B of the cassette base <NUM>, but depending on positions of the thermal head <NUM> and the head driving unit <NUM>, the locating shaft <NUM> may be provided in a dead space formed in a vicinity of a center or in a central lower portion of the back surface 31B. The position of the cylindrical guide body <NUM> may be changed accordingly. Furthermore, a position of the release button <NUM> provided in the handle <NUM> may also be changed depending on the position of the locating shaft <NUM>. Instead of the release button <NUM>, the operation unit may release locking by changing a state of the center shaft <NUM> by a lever or a trigger disposed on a back surface of the handle <NUM>.

In the locating shaft <NUM>, the balls <NUM> and <NUM> are provided on a top and a bottom of the outer peripheral surface of the guide shaft <NUM> to be able to protrude and retract, but the number of balls may be one, or may be two or more. The positions of the balls <NUM> and <NUM> may be positions other than the top and the bottom of the outer peripheral surface of the guide shaft <NUM>.

When the locating shaft <NUM> is inserted into the cylindrical guide body <NUM>, in accordance with a shape of the guide groove <NUM> of the cylindrical guide body <NUM>, each of the guide shaft <NUM> and the cap <NUM> rotates in the clockwise direction about the center shaft <NUM> when viewed from the front end side, but the shape of the guide groove <NUM> may be reversed and each of the guide shaft <NUM> and the cap <NUM> may rotate in the counterclockwise direction about the center shaft <NUM> when viewed from the front end side. In this case, the lock spring <NUM> having an opposite winding direction may be used.

In the above embodiment, the cylindrical collar <NUM> is mounted on the stepped portion <NUM> of the guide shaft <NUM>, and each of the balls <NUM> and <NUM> is partially exposed to the outside while being prevented from falling out by a respective one of the exposure holes <NUM> and <NUM> provided in the cylindrical collar <NUM>, but each of the balls <NUM> and <NUM> may be partially exposed to the outside while the balls <NUM> and <NUM> may be prevented from falling out, for example, by omitting the cylindrical collar <NUM> and reducing the diameter of each of the holes <NUM> and <NUM>.

In the above embodiment, the cap <NUM> is coaxially mounted to a rear end portion of the guide shaft <NUM>, but a guide shaft in which the guide shaft <NUM> is integrated with the cap <NUM> may be used.

Hereinafter, a second embodiment of the present invention will be described with reference to <FIG>. Since the same reference numerals in the drawings denote the same configurations as those in the above embodiment unless there is any additional description, detailed descriptions thereof will be omitted. In the second embodiment, a locating shaft <NUM> and a cylindrical guide body <NUM> are used instead of the locating shaft <NUM> and the cylindrical guide body <NUM>.

A structure of the locating shaft <NUM> will be described. The locating shaft <NUM> includes the holder <NUM>, the guide shaft <NUM>, the fixing ring <NUM>, the cap <NUM>, a center shaft <NUM>, the release button <NUM>, the balls <NUM> and <NUM>, and the cylindrical collar <NUM>. On the other hand, unlike the locating shaft <NUM> in the above embodiment, the locating shaft <NUM> does not include the release spring <NUM> and the lock spring <NUM>.

The center shaft <NUM> is formed in a rod shape extending in a front-rear direction. The center shaft <NUM> includes a first shaft <NUM> and a second shaft <NUM> arranged side by side in the front-rear direction, and a compression spring <NUM> that connects the two shafts <NUM> and <NUM>. The center shaft <NUM> is coaxially inserted and disposed inside the guide hole <NUM> of the guide shaft <NUM> and the guide hole <NUM> of the cap <NUM>, and is supported to be movable along a length direction of the guide shaft <NUM> and the cap <NUM>. A front end side of the center shaft <NUM> (first shaft <NUM>) protrudes forward from the diameter-reduced portion <NUM> of the guide shaft <NUM>. The button fixing portion <NUM> is provided at a front end portion of the center shaft <NUM> (first shaft <NUM>). The recessed portion <NUM> whose diameter is reduced toward an inner side in a radial direction is provided on an outer peripheral surface of a substantially central portion of the center shaft <NUM> (first shaft <NUM>) in the front-rear direction. A biasing spring <NUM> is provided which includes one end connected to the first shaft <NUM> and the other end connected to the cap <NUM> and which biases the first shaft <NUM> rearward. A spring force (spring constant) of the biasing spring <NUM> is set to be smaller than a spring force (spring constant) of the compression spring <NUM>.

The balls <NUM> and <NUM> are disposed inside the holes <NUM> and <NUM> of the guide shaft <NUM>, respectively. The balls <NUM> and <NUM> are in contact with an outer peripheral surface of the center shaft <NUM> (first shaft <NUM>) in the guide hole <NUM> of the guide shaft <NUM>, and slide on the outer peripheral surface of the center shaft <NUM> (first shaft <NUM>) as the center shaft <NUM> (first shaft <NUM>) moves.

The cylindrical collar <NUM> is formed in the short axis cylindrical shape extending in the front-rear direction, and is mounted on the outer peripheral surface of the stepped portion <NUM> of the guide shaft <NUM> similarly to the above embodiment. The cylindrical collar <NUM> is provided with a pair of upper and lower exposure holes <NUM> and <NUM>. As a result, the cylindrical collar <NUM> can allow a part of each of the balls <NUM> and <NUM> to protrude outward from a respective one of the exposure holes <NUM> and <NUM>, and can prevent the balls <NUM> and <NUM> from falling out of the exposure holes <NUM> and <NUM> respectively.

In the locating shaft <NUM>, a position of each of the guide shaft <NUM> and the cap <NUM> centered on the axis is fixed with respect to the holder <NUM>, and the guide shaft <NUM> and the cap <NUM> are attached not to be rotatable.

The cylindrical guide body <NUM> is formed in a substantially cylindrical shape extending forward from the front surface 31A, and the locating shaft <NUM> can be inserted into the cylindrical guide body <NUM> from a front. The cylindrical guide body <NUM> includes the pair of engaged holes <NUM> and an abutment portion <NUM>. Each of the engaged holes <NUM> is formed in a circular shape in a plan view. The abutment portion <NUM> is provided inside the cylindrical guide body <NUM>, and is disposed, in the front-rear direction, at a position where a rear end of the cap <NUM> of the locating shaft <NUM> abuts on the abutment portion <NUM> in the state where the cassette <NUM> is mounted to the main body <NUM>. In a mounted state, the pair of engaged holes <NUM> are disposed at positions facing the exposure holes <NUM> and <NUM>.

Switching of a state of the locating shaft <NUM>, and a method for inserting the locating shaft <NUM> into the cylindrical guide body <NUM> and locking the locating shaft <NUM> will be described with reference to <FIG>. The locating shaft <NUM> shown in <FIG> is in an initial state before the cassette <NUM> is mounted to the main body <NUM>. In the initial state, the release button <NUM> is in a state of being pushed rearward, and inside the guide hole <NUM> of the guide shaft <NUM>, the center shaft <NUM> is biased by the biasing spring <NUM> to move rearward integrally with the release button <NUM>. At this time, the positions of the balls <NUM> and <NUM> face the recessed portion <NUM> of the outer peripheral surface of the center shaft <NUM> (first shaft <NUM>). Therefore, since the balls <NUM> and <NUM> are movable inward in the radial direction, the balls <NUM> and <NUM> respectively move inward from the exposure holes <NUM> and <NUM> by being pushed in from the outside. At this time, the second shaft <NUM> is pushed rearward by the compression spring <NUM>, and a rear end portion of the second shaft <NUM> is in a state of being exposed and protruding from a guide hole of the cap <NUM>.

Similarly to the above embodiment, in the second embodiment, a user grips the handle <NUM> of the cassette <NUM> and disposes the cassette <NUM> on the front side of the main body <NUM> in order to mount the cassette <NUM> to the main body <NUM>. The back surface 41B of the cassette base <NUM> of the cassette <NUM> faces the front surface 31A of the main body base <NUM> of the main body <NUM>. The locating shaft <NUM> on the side of the back surface 41B faces the cylindrical guide body <NUM> on the side of the front surface 31A.

As shown in <FIG>, the user inserts a tip end side of the locating shaft <NUM> into the cylindrical guide body <NUM>. Since the locating shaft <NUM> is in the initial state, the balls <NUM> and <NUM> do not respectively protrude outward from the exposure holes <NUM> and <NUM>, and do not interfere with an inner wall of the cylindrical guide body <NUM>. Therefore, the user can smoothly insert the locating shaft <NUM> into the cylindrical guide body <NUM> without feeling a resistance.

The user moves the cassette <NUM> toward a side of the main body <NUM> in a state of gripping the handle <NUM>. As the locating shaft <NUM> is pushed toward a back side of the cylindrical guide body <NUM>, a rear end of the second shaft <NUM> abuts on the abutment portion <NUM>, and the second shaft <NUM> moves forward with respect to the cap <NUM>. When the second shaft <NUM> moves forward, due to a biasing force of the compression spring <NUM>, the first shaft <NUM> also receives a force to move forward.

The center shaft <NUM> attempts to move forward, so that the balls <NUM> and <NUM> abut against a portion of the outer peripheral surface of the center shaft <NUM> (first shaft <NUM>) behind the recessed portion <NUM>. Therefore, the balls <NUM> and <NUM> are pushed toward an outer side in the radial direction by the outer peripheral surface of the center shaft <NUM> (first shaft <NUM>), and a part of each of the balls <NUM> and <NUM> attempts to protrude from a respective one of the exposure holes <NUM> and <NUM>. However, in the middle of insertion, each of the balls <NUM> and <NUM> cannot completely protrude due to interfering with the inner wall of the guide cylinder <NUM>.

As shown in <FIG>, when the locating shaft <NUM> is pushed into an innermost part of the cylindrical guide body <NUM>, positions of the exposure holes <NUM> and <NUM> are respectively aligned with positions of the pair of engaged holes <NUM>, and the balls <NUM> and <NUM> are released from interference with the inner wall of the guide cylinder <NUM> to protrude outward. Accordingly, the first shaft <NUM> biased by the compression spring <NUM> also moves forward with respect to the guide shaft <NUM> and the cap <NUM>. Therefore, the balls <NUM> and <NUM> are pushed toward the outer side in the radial direction by an outer peripheral surface of the portion of the outer peripheral surface of the first shaft <NUM> behind the recessed portion <NUM>, and a part of each of the balls <NUM> and <NUM> protrudes from a respective one of the engaged holes <NUM> via a respective one of the exposure holes <NUM> and <NUM> to lock the locating shaft <NUM>. By movement of the center shaft <NUM> (first shaft <NUM>), the release button <NUM> also moves forward from the guide shaft <NUM> and the cap <NUM> to transition to a state where the release button <NUM> can be pressed. The biasing spring <NUM> is in a compressed state. As a result, the locating shaft <NUM> is in a locked state of being locked to the cylindrical guide body <NUM>, and the cassette <NUM> is mounted to the main body <NUM>.

A method for releasing the locking of the locating shaft <NUM> to pull out the locating shaft <NUM> from the cylindrical guide body <NUM> will be described. In a state shown in <FIG>, the user presses the release button <NUM> rearward against the spring force of the compression spring <NUM> with a thumb of a hand with which the handle <NUM> is gripped while gripping the handle <NUM> of the cassette <NUM>. Then, the first shaft <NUM> is pushed rearward, so that the positional relationship between the recessed portion <NUM> and the balls <NUM> and <NUM> changes, and the locating shaft <NUM> changes from the locked state (see <FIG>) to a released state (see <FIG>). The user pulls out the locating shaft <NUM> from the cylindrical guide body <NUM> by pulling the handle <NUM> forward. At this time, since each of the balls <NUM> and <NUM> is pushed into the inside of the guide shaft <NUM> by the inner edge portion of a respective one of the exposure holes <NUM> and <NUM>, the locking to the cylindrical guide body <NUM> is released. As a result, the user can easily pull out the locating shaft <NUM> from the cylindrical guide body <NUM>, and can easily remove the cassette <NUM> from the main body <NUM>. When the locating shaft <NUM> is pulled out and the cap <NUM> is separated from the abutment portion <NUM>, the second shaft <NUM> can protrude from the rear end of the cap, and the spring force of the compression spring <NUM> generated when the release button <NUM> is pressed is released. The biasing spring <NUM> also returns from the compressed state to a released state. As a result, a state where the release button <NUM> is pushed rearward is maintained, and the locating shaft <NUM> is switched to the initial state shown in <FIG>.

In the above second embodiment, since the balls <NUM> and <NUM> do not protrude from the beginning of mounting, the balls <NUM> and <NUM> almost do not interfere with the cylindrical guide body <NUM>. Therefore, the user can mount the cassette <NUM> to the main body <NUM> with a small force without feeling the resistance. Since the interference does not occur, damage due to wear or the like of the balls <NUM> and <NUM> can be made extremely small.

Claim 1:
A printing device (<NUM>), comprising:
a main body (<NUM>) having a head support surface on which a thermal head (<NUM>) is supported; and
a cassette (<NUM>) including a plate-shaped cassette base (<NUM>), a supply roll shaft (<NUM>), and a winding roll shaft (<NUM>), and detachably attached to the head support surface of the main body along an axis direction of the supply roll shaft and the winding roll shaft, the supply roll shaft rotatably supporting a ribbon supply roll and being provided on one side, in a predetermined direction, of a facing surface (41B) of the cassette base facing the head support surface, and the winding roll shaft rotatably supporting a ribbon winding roll and being provided on an other side, in the predetermined direction, of the facing surface,
wherein the printing device is configured to perform printing by transferring ink of an ink ribbon onto a print medium due to heating of the thermal head, the ink ribbon being fed out from the ribbon supply roll and wound around the ribbon winding roll through the thermal head, and
wherein the printing device further comprises:
a guided portion (<NUM>, <NUM>) provided on the facing surface of the cassette base; and
a guide portion (<NUM>, <NUM>) provided at a position facing the guided portion on the head support surface of the main body, and configured to guide and locate the guided portion to a predetermined position on a side of the head support surface along the axis direction,
characterized in that the printing device further comprises:
a lock unit (<NUM>) provided in the guided portion and configured to lock the guided portion to the guide portion in a state where the guided portion is located at the predetermined position by the guide portion; and
a release unit (<NUM>) configured to release locking performed by the lock unit.