Patent Description:
Hitherto, there has been known a printing unit which is configured to perform printing by heating a printing surface of a recording sheet with heating elements of a thermal head to develop a color on the printing surface while feeding the recording sheet through rotation of a platen roller under a state in which the recording sheet is nipped between the platen roller and the thermal head (see, for example, <CIT>, along with <CIT>). This printing unit includes the platen roller, a motor, and a frame. The motor is configured to rotate the platen roller. The frame supports the platen roller in a rotatable manner. The frame includes: a pair of side wall portions which hold both ends of the platen roller, respectively; and a support portion which is provided between the pair of side wall portions. The motor is mounted on one of the side wall portions. Mounting portions are provided to the support portion with an interval in an axial direction of the platen roller. The mounting portions are fastened to a casing of a portable terminal on which the printing unit is mounted.

However, in the related art, when the portable terminal including the printing unit is dropped, inertia of the motor with a relatively heavy weight, which is mounted on the frame, is applied to the frame fixed to the casing, and hence, the frame may be broken. Thus, the related-art printing unit has a room for improvement in durability against a drop impact.

The present disclosure has been made in view of such a circumstance, and an object thereof is to provide a printing unit having excellent durability against a drop impact, and a portable terminal including the printing unit.

According to one embodiment of the present invention, there is provided a printing unit in accordance with the appended set of claims.

In the above-mentioned thermal printer according to the one embodiment of the present invention, preferably the protruding portion is connected to the motor support portion.

In the above-mentioned thermal printer according to the one embodiment of the present invention, preferably the protruding portion is one of the mounting portions.

In the above-mentioned thermal printer according to the one embodiment of the present invention, preferably the mounting portions are fastened to the member on which the printing unit is to be mounted.

In the above-mentioned thermal printer according to the one embodiment of the present invention, preferably the mounting portions include a first mounting portion and a second mounting portion which are arranged with an interval in the axial direction, wherein the first mounting portion is provided closer to the motor support portion than the second mounting portion is, and wherein the second mounting portion is provided at an end portion of the frame, which is on a side opposite to the motor support portion with respect to the first mounting portion.

In the above-mentioned thermal printer according to the one embodiment of the present invention, preferably an inclination angle of the guide surface with respect to the normal direction of the head surface of the thermal head is <NUM>° or more and <NUM>° or less.

According to one embodiment of the present invention, there is provided a portable terminal including the above printing unit.

Now, an embodiment of the present invention is described with reference to the drawings. In the following description, components having the same or similar function are denoted by the same reference symbols. In some cases, overlapping description of the components is omitted.

<FIG> is a perspective view for illustrating a portable terminal according to at least one embodiment of the present invention.

As illustrated in <FIG>, a portable terminal <NUM> is capable of performing printing on a recording sheet P. The recording sheet P is a heat sensitive sheet that develops a color when heat is applied thereto, and is used suitably for printing a variety of labels, receipts, and tickets. The recording sheet P is set in the portable terminal <NUM> in a state of a roll sheet R obtained by rolling the recording sheet P so as to have a hollow hole, and printing is performed on a part drawn from the roll sheet R.

The portable terminal <NUM> includes a casing <NUM>, a display unit <NUM>, a control unit <NUM>, and a printing unit <NUM>.

The casing <NUM> formed into a hollow box-shape is made of a metal material or plastic such as ABS or a composite material of ABS and polycarbonate. The casing <NUM> includes a main body portion <NUM> having a rectangular parallelepiped shape, and a roll sheet receiving portion <NUM> formed at one end portion of the main body portion <NUM> in a longitudinal direction thereof so as to be bent toward one side of a thickness direction of the main body portion <NUM>. The printing unit <NUM> is received at the one end portion of the main body portion <NUM> in the longitudinal direction. A discharge port 3a is formed in one end surface of the main body portion <NUM> in the longitudinal direction. The discharge port 3a is configured to discharge the recording sheet P printed by passing through the printing unit <NUM>. The display unit <NUM> is arranged on a main surface of the main body portion <NUM>, which faces the other side in the thickness direction. The display unit <NUM> is, for example, a liquid crystal panel. The display unit <NUM> is connected to the control unit <NUM>, and is configured to display various kinds of information. The roll sheet receiving portion <NUM> is configured to receive the roll sheet R. The printing unit <NUM> is a so-called thermal printer.

<FIG> is a perspective view for illustrating the printing unit according to the embodiment when viewed from an upper front side thereof. <FIG> is an exploded perspective view for illustrating the printing unit according to the embodiment when viewed from the upper front side. <FIG> is a perspective view for illustrating the printing unit according to the embodiment when viewed from an upper rear side thereof.

As illustrated in <FIG>, the printing unit <NUM> includes a platen roller <NUM>, a thermal head <NUM>, a head support plate <NUM>, a motor <NUM>, a flexible printed board <NUM>, and a frame <NUM>. The platen roller <NUM> conveys the recording sheet P. The thermal head <NUM> performs printing on the recording sheet P through press contact with an outer peripheral surface of the platen roller <NUM>. The head support plate <NUM> is arranged on a side opposite to the platen roller <NUM> across the thermal head <NUM> and supports the thermal head <NUM>. The motor <NUM> serves as a drive source of the platen roller <NUM>. The flexible printed board <NUM> electrically connects the control unit <NUM> of the portable terminal <NUM> and each of parts of the printing unit <NUM> to each other. The frame <NUM> supports the platen roller <NUM> and the head support plate <NUM>.

As illustrated in <FIG>, the printing unit <NUM> is configured to convey the recording sheet P passing between the platen roller <NUM> and the thermal head <NUM>, in a direction indicated by an arrow A. Mainly in the description for the printing unit <NUM> below, a direction along the arrow A is defined as a vertical direction, and the direction indicated by the arrow A is defined as an upper side. Further, a direction which is orthogonal to the vertical direction and matches an axial direction of the platen roller <NUM> is defined as a horizontal direction. In addition, a direction orthogonal to the vertical direction and the horizontal direction is defined as a fore-and-aft direction, and the platen roller <NUM> side with respect to the thermal head <NUM> in the fore-and-aft direction is defined as a front side. A left side and a right side each correspond to a direction when viewed from the front side. In the drawings used for the following description, an arrow UP indicates an upper side, an arrow FR indicates a front side, and an arrow LH indicates a left side.

As illustrated in <FIG>, the frame <NUM> is formed of, for example, a plate member such as a polycarbonate resin containing glass fibers. The frame <NUM> is formed into a U-shape opened toward the front side when viewed in the vertical direction. Specifically, the frame <NUM> includes a base portion <NUM> extending in the horizontal direction, a first side wall portion <NUM> protruding from a left end portion of the base portion <NUM> to the front side, and a second side wall portion <NUM> protruding from a right end portion of the base portion <NUM> to the front side and a lower side.

As illustrated in <FIG> and <FIG>, the base portion <NUM> is arranged between the first side wall portion <NUM> and the second side wall portion <NUM>. The base portion <NUM> includes: a rear plate portion <NUM> arranged on a side opposite to the platen roller <NUM> across the head support plate <NUM>; and a sheet guide portion <NUM> arranged in front of the rear plate portion <NUM>. The rear plate portion <NUM> is formed into a plate shape having a thickness in the fore-and-aft direction. The rear plate portion <NUM> is connected to the first side wall portion <NUM> and the second side wall portion <NUM>. The rear plate portion <NUM> extends in the horizontal direction between the first side wall portion <NUM> and the second side wall portion <NUM>. A lower end portion of the rear plate portion <NUM> extends in the horizontal direction. The sheet guide portion <NUM> is connected to the first side wall portion <NUM> and the second side wall portion <NUM>. The sheet guide portion <NUM> extends in the horizontal direction between the first side wall portion <NUM> and the second side wall portion <NUM>. A lower end portion of the sheet guide portion <NUM> extends in the horizontal direction at the same position as that of the lower end portion of the rear plate portion <NUM> in the vertical direction.

<FIG> is a perspective view for illustrating the printing unit according to the embodiment when viewed from a lower front side thereof. <FIG> is a perspective view for illustrating the printing unit according to the embodiment when viewed from a lower rear side thereof. <FIG> is an illustration of a state in which the motor <NUM> and the flexible printed board <NUM> are removed.

As illustrated in <FIG> and <FIG>, the base portion <NUM> includes a connection portion <NUM> connecting the rear plate portion <NUM> and the sheet guide portion <NUM> to each other. The connection portion <NUM> connects the respective lower end portions of the rear plate portion <NUM> and the sheet guide portion <NUM> to each other, and extends in the horizontal direction. An intermediate portion of the connection portion <NUM> in the horizontal direction has an insertion hole <NUM> through which the flexible printed board <NUM> is to be inserted. The insertion hole <NUM> extends through the connection portion <NUM> in the vertical direction and communicates with a space between the rear plate portion <NUM> and the sheet guide portion <NUM>.

As illustrated in <FIG>, the first side wall portion <NUM> is formed into a plate shape having a thickness in the horizontal direction. An upper edge of the first side wall portion <NUM> is cut downward to form a first roller insertion groove 14A. The second side wall portion <NUM> is formed into a plate shape having a thickness in the horizontal direction. An upper edge of the second side wall portion <NUM> is cut downward to form a second roller insertion groove 14B. The first roller insertion groove 14A and the second roller insertion groove 14B are formed so as to match each other when viewed in the horizontal direction. The platen roller <NUM> is removably inserted into the first roller insertion groove 14A and the second roller insertion groove 14B.

A gearbox portion <NUM> is formed on an outer side of the second side wall portion <NUM>. The gearbox portion <NUM> includes a peripheral wall portion <NUM> formed to extend upright from a peripheral edge of the second side wall portion <NUM> toward the outer side in the horizontal direction. That is, the gearbox portion <NUM> is formed of the second side wall portion <NUM> and the peripheral wall portion <NUM>, and is opened toward the outer side in the horizontal direction. The peripheral wall portion <NUM> is opened upward when viewed in the horizontal direction. The peripheral wall portion <NUM> includes a pair of locking recessed portions 16a formed so as to be recessed downward. The pair of locking recessed portions 16a is formed on both front and rear sides of an upper opening of the peripheral wall portion <NUM>, respectively. A gear cover <NUM> is engaged with the pair of locking recessed portions 16a. The gear cover <NUM> covers an inner side of the gearbox portion <NUM> from an outer side thereof in the horizontal direction.

A first reduction gear <NUM> and a second reduction gear <NUM> are assembled inside the gearbox portion <NUM> so as to be rotatable. The first reduction gear <NUM> and the second reduction gear <NUM> mesh with each other.

As illustrated in <FIG> and <FIG>, the second side wall portion <NUM> includes a motor support portion <NUM> supporting the motor <NUM>. The motor support portion <NUM> is connected to the base portion <NUM>. The motor support portion <NUM> extends downward from a portion connected to the base portion <NUM>. The motor support portion <NUM> is formed so as to be arranged on a side opposite to the platen roller <NUM> across the sheet guide portion <NUM> when viewed in the horizontal direction. An inner surface of the motor support portion <NUM> in the horizontal direction serves as a bonding surface to which the motor <NUM> is to be bonded, and is a flat surface orthogonal to the horizontal direction. The motor support portion <NUM> has a through-hole <NUM> through which an output shaft <NUM> (see <FIG>) of the motor <NUM> is to be inserted. The through-hole <NUM> is a circular hole having a center on an output axis of the motor <NUM>.

As illustrated in <FIG>, the motor <NUM> is arranged so that the output axis thereof is parallel to a rotation axis O (see <FIG>) of the platen roller <NUM>. The motor <NUM> is arranged on the side opposite to the platen roller <NUM> across the sheet guide portion <NUM>. The motor <NUM> is bonded to the motor support portion <NUM> (see <FIG>). The output shaft <NUM> of the motor <NUM> penetrates through the second side wall portion <NUM>. The output shaft <NUM> meshes with the first reduction gear <NUM> inside the gearbox portion <NUM>. A housing <NUM> (see <FIG>) of the motor <NUM> is provided with a cylindrical boss (not shown) which is to be inserted into the through-hole <NUM> of the motor support portion <NUM>. Through contact of the cylindrical boss with an inner peripheral surface of the through-hole <NUM> of the motor support portion <NUM>, the motor <NUM> is non-displaceable relative to the motor support portion <NUM> in the vertical direction and the fore-and-aft direction. The flexible printed board <NUM> is connected to the motor <NUM>. The motor <NUM> is electrically connected to the control unit <NUM> (see <FIG>) via the flexible printed board <NUM>. The motor <NUM> is configured to be driven based on a signal from the control unit <NUM>.

The thermal head <NUM> is configured to perform printing on the recording sheet P (see <FIG>). The thermal head <NUM> is formed into a rectangular shape having its longitudinal direction defined as the horizontal direction when viewed in the fore-and-aft direction. The thermal head <NUM> includes a head surface <NUM> and is arranged under a state in which a direction normal to the head surface <NUM> matches the fore-and-aft direction. The head surface <NUM> of the thermal head <NUM> faces to a side opposite to the rear plate portion <NUM> (to the front side). On the head surface <NUM> of the thermal head <NUM>, a large number of heating elements <NUM> are arrayed in the horizontal direction.

The head surface <NUM> is opposed to a printing surface of the recording sheet P, and the recording sheet P may be nipped between the head surface <NUM> and the outer peripheral surface of the platen roller <NUM>. The thermal head <NUM> is connected to the control unit <NUM> (see <FIG>) through intermediation of the flexible printed board <NUM>. A driver IC (not shown) mounted on the thermal head <NUM> is configured to control heat generation of the heating elements <NUM> based on the signal from the control unit <NUM>. Through the control of the heat generation of the heating elements <NUM>, the thermal head <NUM> prints, for example, various kinds of letters and figures on the printing surface of the recording sheet P. The thermal head <NUM> is fixed to the head support plate <NUM> by being bonded thereonto.

The head support plate <NUM> is arranged between the rear plate portion <NUM> and the sheet guide portion <NUM>. The head support plate <NUM> is made of a metal material. The head support plate <NUM> is a plate-like member extending in the horizontal direction between the first side wall portion <NUM> and the second side wall portion <NUM>. The head support plate <NUM> is arranged under a state in which a thickness direction of the head support plate <NUM> matches the fore-and-aft direction. The thermal head <NUM> is held on a front surface of the head support plate <NUM>.

A pair of stoppers 30a configured to regulate a pivot range of the head support plate <NUM> are formed at an upper end portion of the head support plate <NUM>. Each of the pair of stoppers 30a is formed in substantially a quadrangular prism shape and extends outward in the horizontal direction of the head support plate <NUM>. The pair of stoppers 30a are respectively inserted into a hole portion having a rectangular shape formed in an upper part of the first side wall portion <NUM> and a hole portion having a rectangular shape formed in an upper part of the second side wall portion <NUM> in the frame <NUM>. The stoppers 30a are movable inside the hole portions, respectively, along with the pivot of the head support plate <NUM>, and may be brought into contact with inner wall surfaces of the hole portions, respectively. Through the contact of the stoppers 30a with the inner wall surfaces of the hole portions, the pivot amount of the head support plate <NUM> is regulated.

As illustrated in <FIG>, elastic members <NUM> are interposed between the head support plate <NUM> and the rear plate portion <NUM>. The elastic members <NUM> are configured to urge the head support plate <NUM> and the rear plate portion <NUM> in a direction of separating the head support plate <NUM> and the rear plate portion <NUM> from each other. That is, the elastic members <NUM> are configured to always press the head support plate <NUM> toward the front side. A plurality of (three in this embodiment) elastic members <NUM> are arrayed with intervals in the horizontal direction.

<FIG> is a rear view for illustrating a right half of the printing unit according to the embodiment.

As illustrated in <FIG>, the head support plate <NUM> is electrically conducted to the housing <NUM> of the motor <NUM> via a conducting member <NUM>. The conducting member <NUM> is made of a material having conductivity. In this embodiment, the conducting member <NUM> is formed of a metal wire. The conducting member <NUM> is electrically connected to the head support plate <NUM>. The conducting member <NUM> is mechanically and electrically connected to one of the elastic members <NUM>, and is electrically connected to the head support plate <NUM> via the one of the elastic members <NUM>. In this embodiment, the conducting member <NUM> is connected to the elastic member <NUM> arranged on a rightmost side among the plurality of elastic members <NUM>. The conducting member <NUM> may be integrated with the elastic member <NUM>. The conducting member <NUM> penetrates through the rear plate portion <NUM> and extends from a front space of the rear plate portion <NUM> to a rear space of the rear plate portion <NUM>. The conducting member <NUM> is brought into contact with the housing <NUM> of the motor <NUM> in a space below the base portion <NUM>.

As illustrated in <FIG>, the platen roller <NUM> is arranged so as to be opposed to the thermal head <NUM> under a state in which the rotation axis O matches the horizontal direction. The platen roller <NUM> is rotated about the rotation axis O under a state in which the recording sheet P is nipped between the platen roller <NUM> and the thermal head <NUM>, to thereby convey the recording sheet P in the direction indicated by the arrow A.

As illustrated in <FIG>, the platen roller <NUM> includes a roller shaft <NUM>, a roller main body <NUM> mounted on the roller shaft <NUM>, and a pair of bearings <NUM> mounted at both ends of the roller shaft <NUM>. The roller shaft <NUM> is formed slightly longer than the separation distance between the first side wall portion <NUM> and the second side wall portion <NUM> of the frame <NUM>. The roller main body <NUM> is made of, for example, rubber, and is arranged along the horizontal direction uniformly over the entire region excluding portions corresponding to both the ends of the roller shaft <NUM>.

As illustrated in <FIG> and <FIG>, the pair of bearings <NUM> are inserted into the first roller insertion groove 14A and the second roller insertion groove 14B of the frame <NUM>, respectively. The bearings <NUM> are held in the first roller insertion groove 14A and the second roller insertion groove 14B by locking springs <NUM> supported on the frame <NUM>. With this configuration, the platen roller <NUM> is held so as to be rotatable relative to the frame <NUM>. Further, when the locking springs <NUM> are elastically deformed in order to insert and remove the bearings <NUM> into and from the first roller insertion groove 14A and the second roller insertion groove 14B, the platen roller <NUM> is mountable to and removable from the frame <NUM>. Under a state in which the platen roller <NUM> is inserted into the first roller insertion groove 14A and the second roller insertion groove 14B, the platen roller <NUM> is arranged so that the roller main body <NUM> is brought into contact with the thermal head <NUM> through intermediation of the recording sheet P drawn out from the roll sheet R (see <FIG>).

As illustrated in <FIG>, a driven gear <NUM> is fixed on the platen roller <NUM>. The driven gear <NUM> is assembled to an upper part of the gearbox portion <NUM> when the platen roller <NUM> is held on the first side wall portion <NUM> and the second side wall portion <NUM>. The driven gear <NUM> meshes with the second reduction gear <NUM>. With this, a rotational driving force from the motor <NUM> is reduced by the first reduction gear <NUM> and the second reduction gear <NUM>, and then transmitted to the driven gear <NUM>. The platen roller <NUM> is rotated under a state of being held on the first side wall portion <NUM> and the second side wall portion <NUM>, thereby being capable of conveying the recording sheet P (see <FIG>).

The flexible printed board <NUM> electrically connects between the control unit <NUM> of the portable terminal <NUM> and the thermal head <NUM>, the motor <NUM>, and a sensor <NUM> described later through a wiring pattern formed on the flexible printed board <NUM>. The flexible printed board <NUM> is connected to the thermal head <NUM> between the rear plate portion <NUM> and the sheet guide portion <NUM> on the frame <NUM>. The flexible printed board <NUM> extends from a portion connected to the thermal head <NUM> toward the lower side of the frame <NUM> through the insertion hole <NUM> of the connection portion <NUM> of the frame <NUM> (see <FIG>).

The sensor <NUM> is mounted on the flexible printed board <NUM>. The sensor <NUM> is configured to detect the recording sheet P which is being moved toward the thermal head <NUM> while being guided by a guide surface <NUM> described later. The sensor <NUM> is, for example, a reflection PI sensor. The sensor <NUM> is configured such that a light emitted from a light emitting portion is reflected by the recording sheet P so that the reflected light can be detected by a light receiving portion. For example, when a reflected light having a predetermined intensity is detected by the light receiving portion of the sensor <NUM>, the control unit <NUM> of the portable terminal <NUM> determines that the recording sheet P is present within a detection range of the sensor <NUM>.

The sheet guide portion <NUM> is formed into a columnar shape extending along the horizontal direction. The sheet guide portion <NUM> includes the guide surface <NUM> which is configured to guide, toward the thermal head <NUM>, the recording sheet P drawn out from the roll sheet R (see <FIG>) in front of the printing unit <NUM>. The entire guide surface <NUM> extends downward and forward from an upper edge, which is closer to the thermal head <NUM>, of the sheet guide portion <NUM>, and faces a space in front of the printing unit <NUM>. Specifically, the guide surface <NUM> includes: a first guide surface <NUM> extending forward and downward from the upper edge of the sheet guide portion <NUM>; and a second guide surface <NUM> extending downward from a front edge of the first guide surface <NUM>. Each of the first guide surface <NUM> and the second guide surface <NUM> is a flat surface extending in the horizontal direction.

<FIG> is a sectional view taken along the line VIII-VIII of <FIG>.

As illustrated in <FIG>, it is desired that the first guide surface <NUM> be inclined in an angle range of <NUM>° or more and <NUM>° or less with respect to the normal direction of the head surface <NUM> of the thermal head <NUM> (the direction normal to the head surface <NUM> of the thermal head <NUM>). In this embodiment, the first guide surface <NUM> is inclined at <NUM>° with respect to the normal direction of the head surface <NUM> of the thermal head <NUM>. That is, in a section orthogonal to the horizontal direction, an angle "α" formed by a tangent of the first guide surface <NUM> and a normal direction of the head surface <NUM> of the thermal head <NUM> is <NUM>°. A rear surface of the sheet guide portion <NUM> is continuous to a rear edge of the first guide surface <NUM>. A lower surface of the sheet guide portion <NUM> is continuous to a lower edge of the second guide surface <NUM>.

As illustrated in <FIG>, an accommodation portion <NUM> for accommodating the sensor <NUM> is formed in the sheet guide portion <NUM>. The accommodation portion <NUM> is formed into a recessed shape opened to the guide surface <NUM>. Further, the accommodation portion <NUM> is opened over the rear surface and the lower surface of the sheet guide portion <NUM> from the guide surface <NUM>.

<FIG> is a bottom view for illustrating the printing unit according to the embodiment. Note that, <FIG> is an illustration of a state in which the motor <NUM> and the flexible printed board <NUM> are removed.

As illustrated in <FIG> and <FIG>, the frame <NUM> includes mounting portions <NUM> which are to be attached to the casing <NUM> serving as a member on which the printing unit <NUM> is to be mounted. The mounting portions <NUM> includes a right-side mounting portion <NUM> (first mounting portion) and a left-side mounting portion <NUM> (second mounting portion) which are arranged with an interval in the horizontal direction.

The right-side mounting portion <NUM> is provided closer to the motor support portion <NUM> than the left-side mounting portion <NUM> is (that is, on the right side of the left-side mounting portion <NUM>). The right-side mounting portion <NUM> is provided on the second side wall portion <NUM> side from an intermediate position in the horizontal direction between the first side wall portion <NUM> and the second side wall portion <NUM>. The right-side mounting portion <NUM> is provided within a formation range of the insertion hole <NUM> in the horizontal direction. The right-side mounting portion <NUM> includes a right-side positioning portion <NUM> and a right-side fastening portion <NUM>.

The right-side positioning portion <NUM> is provided in the sheet guide portion <NUM>. The right-side positioning portion <NUM> has a right-side positioning recessed portion 72a into which a first positioning pin (not shown) of the casing <NUM> is to be inserted. The right-side positioning recessed portion 72a is opened to the lower surface of the sheet guide portion <NUM>. The opening of the right-side positioning recessed portion 72a has an elliptical shape with its longitudinal direction defined as the horizontal direction. The right-side positioning recessed portion 72a may extend through the frame <NUM>.

The right-side fastening portion <NUM> is provided on a rear side of the right-side positioning portion <NUM>. The right-side fastening portion <NUM> protrudes rearward with a constant width from the lower end portion of the rear plate portion <NUM>. The right-side fastening portion <NUM> has a right-side fastening hole 73a through which a fastening member for fastening to the casing <NUM> is to be inserted. The right-side fastening hole 73a extends through the right-side fastening portion <NUM> in the vertical direction. At least a part of a formation range of the right-side fastening hole 73a in the horizontal direction overlaps a formation range of the right-side positioning recessed portion 72a in the horizontal direction.

As illustrated in <FIG>, a pair of reinforcement ribs <NUM> are connected to the right-side fastening portion <NUM>. The reinforcement ribs <NUM> each connect an upper surface of the right-side fastening portion <NUM> and a rear surface of the rear plate portion <NUM> to each other. The reinforcement ribs <NUM> each extend rearward with a constant thickness from the rear surface of the rear plate portion <NUM>. The pair of reinforcement ribs <NUM> are arranged with an interval from each other in the horizontal direction such that the right-side fastening hole 73a is located therebetween. The pair of reinforcement ribs <NUM> are connected to right and left end portions of the right-side fastening portion <NUM>, respectively. Each of the reinforcement ribs <NUM> is formed into a right triangle when viewed in a thickness direction of the reinforcement ribs <NUM> (in the horizontal direction), and two sides forming a right angle in the right triangle are connected to the rear plate portion <NUM> and the right-side fastening portion <NUM>, respectively. The reinforcement ribs <NUM> are each connected to the entire right-side fastening portion <NUM> in the fore-and-aft direction.

As illustrated in <FIG> and <FIG>, the left-side mounting portion <NUM> is provided at an end portion (left end portion) of the frame <NUM>, which is on a side opposite to the motor support portion <NUM> with respect to the right-side mounting portion <NUM>. The left-side mounting portion <NUM> is provided outside the formation range of the insertion hole <NUM> in the horizontal direction. The left-side mounting portion <NUM> includes a left-side positioning portion <NUM> and a left-side fastening portion <NUM>.

The left-side positioning portion <NUM> is provided at a left end portion of the sheet guide portion <NUM>. The left-side positioning portion <NUM> has a left-side positioning recessed portion 77a into which a second positioning pin (not shown) of the casing <NUM> is to be inserted. The left-side positioning recessed portion 77a is opened to the lower surface of the sheet guide portion <NUM>. The opening of the left-side positioning recessed portion 77a has a circular shape. The left-side positioning recessed portion 77a may extend through the frame <NUM>.

The left-side fastening portion <NUM> is provided on a rear side of the left-side positioning portion <NUM>. The left-side fastening portion <NUM> is arranged with an interval from the right-side fastening portion <NUM> in the horizontal direction. The left-side fastening portion <NUM> is provided at the left end portion of the sheet guide portion <NUM>. The left-side fastening portion <NUM> protrudes rearward with a constant width from a lower end portion of the left end portion of the rear plate portion <NUM>. The left-side fastening portion <NUM> has a left-side fastening hole 78a through which a fastening member for fastening to the casing <NUM> is to be inserted. The left-side fastening hole 78a extends through the left-side fastening portion <NUM> in the vertical direction. At least a part of a formation range of the left-side fastening hole 78a in the horizontal direction overlaps a formation range of the left-side positioning recessed portion 77a in the horizontal direction.

As illustrated in <FIG>, a pair of reinforcement ribs <NUM> are connected to the left-side fastening portion <NUM>. The reinforcement ribs <NUM> each connect an upper surface of the left-side fastening portion <NUM> and the rear surface of the rear plate portion <NUM> to each other. The reinforcement ribs <NUM> each extend rearward with a constant thickness from the rear surface of the rear plate portion <NUM>. The pair of reinforcement ribs <NUM> are arranged with an interval from each other in the horizontal direction such that the left-side fastening hole 78a is located therebetween. The pair of reinforcement ribs <NUM> are connected to right and left end portions of the left-side fastening portion <NUM>, respectively. Each of the reinforcement ribs <NUM> is formed into a right triangle when viewed in a thickness direction of the reinforcement ribs <NUM> (in the horizontal direction), and two sides forming a right angle in the right triangle are connected to the rear plate portion <NUM> and the left-side fastening portion <NUM>, respectively. The reinforcement ribs <NUM> are each connected to the entire left-side fastening portion <NUM> in the fore-and-aft direction. The reinforcement rib <NUM> on the left side is provided so as to extend the first side wall portion <NUM>.

As illustrated in <FIG>, the frame <NUM> further includes a standing wall <NUM> and ribs <NUM>.

The standing wall <NUM> protrudes downward from the sheet guide portion <NUM>. The standing wall <NUM> is provided so as to overlap the housing <NUM> of the motor <NUM> when viewed from the front side, and covers an outer periphery of the motor <NUM> (see <FIG>). The standing wall <NUM> is provided closer to the motor support portion <NUM> than the right-side mounting portion <NUM> is. The standing wall <NUM> is arranged with an interval from the right-side mounting portion <NUM> in the horizontal direction. The standing wall <NUM> extends downward with a constant width when viewed in the fore-and-aft direction, from a right end portion of the sheet guide portion <NUM>. The standing wall <NUM> extends in the horizontal direction with a constant thickness when viewed from the lower side. A right end portion of the standing wall <NUM> is connected to the motor support portion <NUM>. A lower edge of the standing wall <NUM> extends in the horizontal direction. A front surface of the standing wall <NUM> is a flat surface continuous to the second guide surface (<NUM>) <NUM> of the sheet guide portion <NUM> (see <FIG>). A lower end surface 65a of the standing wall <NUM> is a concave curved surface extending along an outer peripheral surface of the housing <NUM> of the motor <NUM>. The lower end surface 65a extends in the horizontal direction with a constant interval with respect to the outer peripheral surface of the housing <NUM> of the motor <NUM>.

A small rib <NUM> is connected to the standing wall <NUM>. The small rib <NUM> is connected to a left end portion of the standing wall <NUM>. The small rib <NUM> connects a rear surface of the standing wall <NUM> and the lower surface of the sheet guide portion <NUM> to each other. The small rib <NUM> extends rearward with a constant thickness from the standing wall <NUM> when viewed from the lower side. A connection part between the small rib <NUM> and the base portion <NUM> is located within an area of the sheet guide portion <NUM>. A lower end surface 66a of the small rib <NUM> is continuous to the lower end surface 65a of the standing wall <NUM>, and extends along the outer peripheral surface of the housing <NUM> of the motor <NUM>. The lower end surface 66a extends with a substantially constant interval with respect to the outer peripheral surface of the housing <NUM> of the motor <NUM>.

The ribs <NUM> are provided between an entirety of the mounting portions <NUM> and the motor support portion <NUM>. That is, the ribs <NUM> are provided on the right side of the mounting portions <NUM>. The ribs <NUM> connect the base portion <NUM> and protruding portions (the standing wall <NUM> and the right-side mounting portion <NUM>) protruding from the base portion <NUM> to each other, respectively. The ribs <NUM> include a first rib <NUM> and a second rib <NUM>.

The first rib <NUM> connects the front surface of the standing wall <NUM> and a lower surface of the base portion <NUM> to each other. The first rib <NUM> is provided closer to the motor support portion <NUM> than the small rib <NUM> is. In this embodiment, the first rib <NUM> is connected to a portion of the standing wall <NUM>, which is on the motor support portion <NUM> side from a center position of the standing wall <NUM> in the horizontal direction thereof. The first rib <NUM> extends rearward with a constant thickness from the standing wall <NUM> when viewed from the lower side. The first rib <NUM> is connected continuously to the sheet guide portion <NUM>, the connection portion <NUM>, and the rear plate portion <NUM>. The first rib <NUM> includes a lower end surface 81a extending along the outer peripheral surface of the housing <NUM> of the motor <NUM>. The lower end surface 81a is continuous to the lower end surface 65a of the standing wall <NUM>. The lower end surface 81a extends with a substantially a constant interval with respect to the outer peripheral surface of the housing <NUM> of the motor <NUM>.

The second rib <NUM> connects a right end surface of the right-side fastening portion <NUM> and the rear surface of the rear plate portion <NUM> to each other. The second rib <NUM> is connected to the entire right end surface of the right-side fastening portion <NUM> in the fore-and-aft direction. The second rib <NUM> is connected to the rear surface of the rear plate portion <NUM> over an entire length of the second rib <NUM> in the horizontal direction thereof. An end surface 82a of the second rib <NUM> extends linearly rightward from the connection portion <NUM> between the second rib <NUM> and the right-side fastening portion <NUM>, and then, extends linearly rightward and forward to a right end portion of the second rib <NUM> (see <FIG>). The right end portion of the second rib <NUM> is located at the same position as that of the first rib <NUM> in the fore-and-aft direction (see <FIG>). Accordingly, a formation range of the second rib <NUM> in the horizontal direction overlaps a formation range of the first rib <NUM> in the horizontal direction. A lower surface of the second rib <NUM> is formed into a recessed shape. An upper surface of the second rib <NUM> is a flat surface continuous to the upper surface of the right-side fastening portion <NUM> (see <FIG>).

As illustrated in <FIG>, a conducting member arrangement portion <NUM> in which the conducting member <NUM> is to be arranged is formed in the base portion <NUM>. The conducting member arrangement portion <NUM> is provided closer to the motor support portion <NUM> than the right-side fastening portion <NUM> is. The conducting member arrangement portion <NUM> includes a vertical groove <NUM>, a horizontal groove <NUM>, and a slit <NUM>. The vertical groove <NUM> and the horizontal groove <NUM> are formed in the rear surface of the rear plate portion <NUM>.

The vertical groove <NUM> extends in the vertical direction. An upper end portion of the vertical groove <NUM> communicates with a space in front of the rear plate portion <NUM> via a through-hole through which the conducting member <NUM> is to be inserted. The vertical groove <NUM> is defined by a first wall portion 96A from the right side. The first wall portion 96A extends in the vertical direction with a substantially constant width when viewed from the rear side. With this configuration, a first recessed portion <NUM> recessed forward is formed on a side opposite to the vertical groove <NUM> across the first wall portion 96A.

The horizontal groove <NUM> extends in the horizontal direction. A left end portion of the horizontal groove <NUM> is connected to a lower end portion of the vertical groove <NUM>. The horizontal groove <NUM> is defined by a second wall portion 96B from the upper side. The second wall portion 96B extends in the horizontal direction with a substantially constant width when viewed from the rear side. A left end portion of the second wall portion 96B is connected to a lower end portion of the first wall portion 96A. With this configuration, the second wall portion 96B defines the first recessed portion <NUM> from the lower side. A first reinforcement wall portion <NUM> defining the first recessed portion <NUM> from the right side is connected to the second wall portion 96B. The first reinforcement wall portion <NUM> extends upward from a right end portion of the second wall portion 96B.

The horizontal groove <NUM> is defined by a third wall portion 96C from the lower side. The third wall portion 96C extends in the horizontal direction with a substantially constant width when viewed from the rear side. With this configuration, a second recessed portion <NUM> recessed forward is formed on a side opposite to the horizontal groove <NUM> across the third wall portion 96C. The second recessed portion <NUM> is defined by the second rib <NUM> from the lower side. A second reinforcement wall portion <NUM> defining the second recessed portion <NUM> from the right side is connected to the third wall portion 96C. The second reinforcement wall portion <NUM> extends downward from the third wall portion 96C, and then, is connected to the first rib <NUM>.

As illustrated in <FIG> and <FIG>, the slit <NUM> is cut forward from the rear surface of the rear plate portion <NUM>. The cutting of the slit <NUM> extends through the connection portion <NUM> to the sheet guide portion <NUM>. The slit <NUM> extends in the vertical direction when viewed from the rear side. The slit <NUM> is connected to a right end portion of the horizontal groove <NUM>. The slit <NUM> is opened to the lower surface of the base portion <NUM> between the motor support portion <NUM> and the first rib <NUM>. In the lower surface of the base portion <NUM>, the slit <NUM> is opened from the rear plate portion <NUM> to the sheet guide portion <NUM>. In the slit <NUM>, a meandering portion of the conducting member <NUM> extends vertically while meandering in the fore-and-aft direction. The meandering portion is compressed in the vertical direction in the slit <NUM>. A lower end portion of the meandering portion is brought into press contact with the housing <NUM> of the motor <NUM>. An upper end portion of the meandering portion is connected to a portion of the elastic member <NUM>, which extends along the horizontal groove <NUM> and the vertical groove <NUM>.

As described above, in this embodiment, the base portion <NUM> of the frame <NUM> includes the first guide surface (<NUM>) <NUM> configured to guide the recording sheet P toward the thermal head <NUM>, and the first guide surface (<NUM>) <NUM> is inclined with respect to the normal direction of the head surface <NUM> of the thermal head <NUM>. Thus, compared to a configuration in which the guide surface (<NUM>) extends along the normal direction of the head surface of the thermal head, a sectional area of a transverse section of the base portion <NUM> is reduced, and hence, rigidity of the base portion <NUM> is reduced accordingly.

In view of the above, the frame <NUM> according to this embodiment is provided with: the right-side fastening portion <NUM> and the standing wall <NUM> each protruding from the base portion <NUM>; and the ribs <NUM> provided between the motor support portion <NUM> and the mounting portions <NUM> and extending so as to connect the base portion <NUM> and each of the right-side fastening portion <NUM> and the standing wall <NUM>. According to this configuration, the right-side fastening portion <NUM> and the standing wall <NUM> are firmly connected to the base portion <NUM>. Thus, a portion of the base portion <NUM> between the motor support portion <NUM> and the mounting portions <NUM> can be reinforced by the right-side fastening portion <NUM>, the standing wall <NUM>, and the ribs <NUM>. As a result, when a drop impact is applied, with the mounting portions <NUM> fixed to the casing <NUM> of the portable terminal <NUM> as a fulcrum, so that the motor support portion <NUM> supporting the motor <NUM> being a heavy component swings, breakage of the portion of the base portion <NUM> between the motor support portion <NUM> and the mounting portions <NUM> can be suppressed. Accordingly, it is possible to provide the printing unit <NUM> having excellent durability against the drop impact.

Further, the standing wall <NUM> is connected to the motor support portion <NUM>. According to this configuration, a load applied to the motor support portion <NUM> can be received by not only the base portion <NUM> but also the standing wall <NUM>. Due to being connected to the first rib <NUM>, the standing wall <NUM> is hard to be displaced relative to the base portion <NUM>, and hence, when the drop impact is applied, the breakage of the portion of the base portion <NUM> between the motor support portion <NUM> and the mounting portions <NUM> can be more reliably suppressed.

The second rib <NUM> is connected to the right-side fastening portion <NUM> which is one of the mounting portions <NUM>. According to this configuration, a load applied from the motor support portion <NUM> to the base portion <NUM> can be transmitted not only to a connection part between the base portion <NUM> and the right-side fastening portion <NUM> but also to the right-side fastening portion <NUM> via the second rib <NUM>. With this configuration, stress concentration is suppressed from occurring on the connection part between the base portion <NUM> and the right-side fastening portion <NUM>. Thus, when the drop impact is applied, the breakage of the portion of the base portion <NUM> between the motor support portion <NUM> and the right-side fastening portion <NUM> can be more reliably suppressed.

The right-side fastening portion <NUM> is fastened to the casing <NUM>. According to this configuration, the right-side fastening portion <NUM> is non-displaceable relative to the casing <NUM>, and hence, a load transmitted from the motor support portion <NUM> to the right-side fastening portion <NUM> via the base portion <NUM> is hard to be released, and the stress concentration is liable to occur on the connection part between the base portion <NUM> and the right-side fastening portion <NUM>. Accordingly, the effects described above can be achieved more effectively by providing the second rib <NUM> which extends so as to connect the right-side fastening portion <NUM> and the base portion <NUM> to each other.

The right-side mounting portion <NUM> is provided closer to the motor support portion <NUM> than the left-side mounting portion <NUM> is. In this case, when the drop impact is applied so that the motor support portion <NUM> swings, the frame <NUM> is deformed such that the right-side mounting portion <NUM> closer to the motor support portion <NUM> serves as a fulcrum, the motor support portion <NUM> serves as a point of force, and a portion of the base portion <NUM> between the right-side mounting portion <NUM> and the left-side mounting portion <NUM> serves as a point of action. That is, a load of the motor support portion <NUM> is transmitted to the frame <NUM> so as to deflect the portion of the base portion <NUM> between the right-side mounting portion <NUM> and the left-side mounting portion <NUM>. At this time, in a case in which the base portion <NUM> is formed to be hard to be deflected, stress concentration occurs on a specific portion such as a recessed portion in the base portion <NUM> so that cracks may be easily caused thereon.

In this embodiment, the left-side mounting portion <NUM> is provided at the end portion of the frame <NUM>, which is on the side opposite to the motor support portion <NUM> with respect to the right-side mounting portion <NUM>. According to this configuration, compared to a configuration in which the left-side mounting portion <NUM> is not provided at the end portion of the frame <NUM>, a portion of the base portion <NUM> can be formed longer in the horizontal direction between the right-side mounting portion <NUM> and the left-side mounting portion <NUM>. As a result, the entire portion of the base portion <NUM> between the right-side mounting portion <NUM> and the left-side mounting portion <NUM> is easily deflected. Thus, the load of the motor support portion <NUM> transmitted to the portion of the base portion <NUM> between the right-side mounting portion <NUM> and the left-side mounting portion <NUM> can be dispersed in a wider range of the frame <NUM> in the horizontal direction. Accordingly, breakage of the portion of the base portion <NUM> between the right-side mounting portion <NUM> and the left-side mounting portion <NUM> can be suppressed.

The inclination angle of the first guide surface (<NUM>) <NUM> with respect to the normal direction of the head surface <NUM> of the thermal head <NUM> is <NUM>° or more and <NUM>° or less. With this configuration, when the recording sheet P is guided toward the thermal head <NUM>, even under a specific temperature condition in which adhesiveness of a label being the recording sheet P is degraded, removal of the label can be prevented.

Further, the portable terminal <NUM> according to this embodiment includes the printing unit <NUM>, and thus, can serve as a printer having excellent durability against the drop impact.

Note that, the present invention is not limited to the embodiment described above with reference to the drawings, and various modification examples may be employed within the technical scope of the present invention as defined by the appended claims.

For example, in the above-mentioned embodiment, the motor <NUM> is arranged below the base portion <NUM> of the frame <NUM>, but arrangement of the motor is not particularly limited, and arrangement of the motor support portion can also be changed appropriately in accordance with a position of the motor.

In the above-mentioned embodiment, the motor <NUM> is bonded to the motor support portion <NUM> of the frame <NUM>, but a method of fixing the motor is not particularly limited. For example, the motor may be fastened to the motor support portion.

In the above-mentioned embodiment, the right-side fastening portion <NUM> and the standing wall <NUM> are provided as the protruding portions of the frame <NUM>, but the number of the protruding portions is not particularly limited. Further, in a case in which a plurality of protruding portions protruding from the base portion are provided between the motor support portion and the mounting portions, it is only required that a rib be connected to at least one of the plurality of protruding portions.

Claim 1:
A printing unit (<NUM>), comprising:
a platen roller (<NUM>) configured to convey a recording sheet (P);
a thermal head (<NUM>) configured to perform printing on the recording sheet (P) through press contact with an outer peripheral surface of the platen roller (<NUM>);
a motor (<NUM>) configured to serve as a drive source of the platen roller (<NUM>); and
a frame (<NUM>) configured to support the platen roller (<NUM>) in a rotatable manner,
wherein the frame (<NUM>) includes:
a motor support portion (<NUM>) configured to support the motor (<NUM>);
a base portion (<NUM>) which is connected to the motor support portion (<NUM>), and extends in an axial direction of the platen roller (<NUM>);
mounting portions (<NUM>) which are attached to a member on which the printing unit (<NUM>) is to be mounted;
a protruding portion (<NUM>) which protrudes from the base portion (<NUM>); and
a rib (<NUM>) which is provided between the motor support portion (<NUM>) and the mounting portions (<NUM>), and extends so as to connect the protruding portion and the base portion (<NUM>) to each other,
the base portion (<NUM>) includes a guide surface (<NUM>) configured to guide the recording sheet (P) toward the thermal head (<NUM>), and
the guide surface (<NUM>) is inclined with respect to a direction normal to a head surface of the thermal head (<NUM>);
characterized in that
wherein the printing unit (<NUM>) further comprises a fastening portion (<NUM>) which protrudes from the base portion (<NUM>),
the fastening portion (<NUM>) and the protruding portion (<NUM>) being provided between the motor support portion (<NUM>) and the mounting portions (<NUM>).