Patent Description:
Embodiments described herein relate generally to a printer.

Conventionally, a printer that can print an image on a rolled sheet is used in a store or the like. The rolled sheet is formed by winding a print sheet in a roll shape. The printer prints an image after pulling out a part of the print sheet from the rolled sheet. In addition, in order to reduce the time and effort for the operator to replace the rolled sheet, a so-called drop-in method has been proposed in which the rolled sheet can be loaded only by inserting the rolled sheet into a storage unit of the printer.

In such a drop-in printer, since the core of the rolled sheet is not fixed to the storage unit, when printing is performed, the rolled sheet is pulled out from the rolled sheet in the sheet discharge direction, and the rolled sheet is irregularly moved inside the printer. This movement makes it difficult for the printer to detect that the printing sheet is close to being out of paper.

To prevent that movement, there is a known printer with a pressing roller that presses the rolled sheet from the downstream side (i.e., sheet discharge side) toward the upstream side (i.e., rolled sheet side).

However, in such a printer, the direction in which the rolled sheet is pressed and the direction in which the print sheet is pulled out are opposite to each other. Thus, when the printer main body is placed vertically, if the remaining amount of the rolled sheet decreases, the rolled sheet may slip down in the gravitational direction. Further, when the rolled sheet slips down, there is a case where it is not possible to detect that the rolled sheet is close to the paper shortage. <CIT>, <CIT>, <CIT>, <CIT> and <CIT> are examples of printers comprising sensor to detect a remaining amount of paper according to the state of the art.

Embodiments provide a drop-in printer capable of accommodating a print sheet in a storage unit even in a state where the remaining amount of the print sheet is small.

In one embodiment, a printer includes a housing in which a sheet is stored in a rolled shape, a head by which an image is printed on the sheet, a flapper configured to pivot around an axis at a first end thereof including a surface extending from the first end to a second end of the flapper and biased to press the stored sheet against the housing, and a protrusion at the first end of the flapper that rotates around the axis as the flapper pivots, a sensor, and a controller configured to issue a signal when the protrusion is rotated around the axis to move into a detection range of the sensor.

According to a first aspect of the invention, it is provided a printer according to claim <NUM>.

Optionally, in the printer according to the first aspect of the invention, the sensor is a photosensor including a light emitter that emits light and a light receiver that faces the light emitter and receives the light, and the detection range is between the light emitter and the light receiver.

Optionally, in the printer according to the first aspect of the invention, housing includes a recess that the stored sheet having a diameter smaller than a predetermined diameter can enter.

Optionally, in the printer according to the first aspect of the invention, protrusion is rotated to move into the detection range when the stored sheet has entered the recess.

Optionally, in the printer according to the first aspect of the invention, the housing includes an inclined surface that is inclined with respect to the cover.

Optionally, in the printer according to the first aspect of the invention, the head is located at one end of the inclined surface, and the recess is located at the other end of the inclined surface that is farther from the cover than said one end of the inclined surface.

Optionally, in the printer according to the first aspect of the invention, a step portion is formed between the other end of the inclined surface and the recess so as to contact the stored sheet having a diameter equal to or greater than the predetermined diameter.

Optionally, in the printer according to the first aspect of the invention, the flapper includes a torsion spring that generates a bias force for the surface of the flapper.

Optionally, in the printer according to the first aspect of the invention, the sheet is a thermal sheet, and the head includes a plurality of heating elements to form the image on the thermal sheet.

According to a second non claimed aspect, it is provided a printer comprising a housing in which a sheet is stored in a rolled shape; a head by which an image is printed on the sheet; a flapper configured to pivot around an axis at a first end thereof and biased to press the stored sheet against the housing; a protrusion that rotates around the axis as the flapper pivots; a sensor; and a controller configured to issue a signal when the protrusion is rotated around the axis to move into a detection range of the sensor.

Hereinafter, a thermal printer <NUM> according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

An overall configuration of the thermal printer <NUM> according to an embodiment will be described with reference to <FIG> is a perspective view illustrating an example of an external appearance of the thermal printer <NUM>.

Further, in the drawings described below, for convenience, the X-axis, the Y-axis, and the Z-axis orthogonal to each other are shown, and the left-right direction (X-direction), the front-rear direction (Y-direction), and the up-down direction (Z-direction) in the thermal printer <NUM> be described using the X-axis, the Y-axis, and the Z-axis. In the following description, when simply referred to as the X direction, the Y direction, or the Z direction, it is the respective axial directions, and includes two directions in opposite directions. In addition, when the positive direction of the X-axis is specified, the direction is one direction from the right side to the left side, when the positive direction of the Y-axis is specified, the direction is one direction from the rear side to the front side, and when the positive direction of the Z-axis is specified, the direction is one direction from the lower side to the upper side.

The thermal printer <NUM> includes a lower housing <NUM>, an upper cover <NUM>, and a discharge port <NUM>. The lower housing <NUM> is a box-shaped container in which an opening is provided along its upper surface. The lower housing <NUM> is provided with a connection terminal (not shown) used for connection with an external device such as a host computer for managing the thermal printer <NUM>, a power supply terminal (not shown) for supplying power to the printer <NUM>, and the like. The upper cover <NUM> covers a storage unit <NUM> disposed in the lower housing <NUM> (see <FIG>). The upper cover <NUM> is rotatably supported along one end of the lower housing <NUM>, and covers the opening of the lower housing <NUM> in accordance with the rotation.

The discharge port <NUM> is a gap-shaped opening through which a sheet is discharged, and the opening is formed between the other end of the upper cover <NUM> and the lower housing <NUM>. The lower housing <NUM> and the upper cover <NUM> constitute the housing <NUM>.

Next, the internal structure of the thermal printer <NUM> will be described with reference to <FIG> and <FIG> is a YZ cross-sectional view of the thermal printer <NUM> according to an embodiment. As shown in <FIG> and <FIG>, the thermal printer <NUM> stores a thermal paper <NUM> as a rolled sheet <NUM> wound around a roll core <NUM> in a roll shape in the storage unit <NUM> of the housing <NUM>, and performs printing while drawing the thermal paper <NUM> out of the rolled sheet <NUM>.

The rolled sheet <NUM> in <FIG> shows a state in which the remaining amount of the rolled sheet <NUM> is sufficient. The rolled sheet <NUM> in <FIG> shows a state in which the remaining amount of the rolled sheet <NUM> is small (i.e., has reached a predetermined amount). The print sheet is not limited to the thermal paper <NUM>, and may be, for example, a label sheet. The label sheet may include a plurality of strip-shaped labels each having a predetermined size and attached to a strip-shaped base sheet, or may include a plurality of strip-shaped labels without any base sheet.

The thermal printer <NUM> includes a flapper <NUM>, a platen roller <NUM>, a thermal head <NUM>, and the storage unit <NUM> inside the housing <NUM>.

The thermal printer <NUM> draws the thermal paper <NUM> from the rolled sheet <NUM> by the rotation of the platen roller <NUM>, and performs printing on the drawn thermal paper <NUM> by the thermal head <NUM>.

The flapper <NUM> is also referred to as a pressing member. The flapper <NUM> is provided on the rear side of the upper cover <NUM>. The flapper <NUM> is rotatably attached to the upper cover <NUM> an end portion of the side close to the thermal head <NUM>, and with its rotation, the rolled sheet <NUM> accommodated in the storage unit <NUM> is pressed in a direction away from the upper cover <NUM> side against an inner wall <NUM> of the storage unit <NUM>.

Here, the shape of the flapper <NUM> will be described. <FIG> is a side view illustrating an example of the shape of the flapper <NUM>. <FIG> is a perspective view illustrating the example of the shape of the flapper <NUM>.

A flapper base portion <NUM> at the base of the flapper <NUM> includes a flapper rotation shaft <NUM>. The flapper rotation shaft <NUM> is rotatably supported along the rear surface of the upper cover <NUM>. Further, a sheet holding unit <NUM> is formed at the leading end of the flapper <NUM>.

The sheet holding unit <NUM> is a member extending from the flapper base portion <NUM> at the root of the flapper <NUM> to the Y-axis direction negative side. The sheet holding unit <NUM> is brought into contact with the rolled sheet <NUM> to press the outer peripheral surface of the rolled sheet <NUM> against the storage unit <NUM> described later.

The flapper <NUM> is mounted along the rear surface side of the upper cover <NUM> so as to be rotatable around the flapper rotation shaft <NUM> in a state of being biased in the direction of the rolled sheet <NUM> accommodated in the storage unit <NUM>.

Further, the flapper base portion <NUM> includes a protruding portion <NUM> which is a thin piece protruding in the radial direction around the flapper rotation shaft <NUM>. The protruding portion <NUM> is a member that is provided at an end portion of the flapper base portion <NUM> that is rotatably attached to the upper cover <NUM> and protrudes in the radial direction of the rotation. The protruding portion <NUM> is a member for causing a photosensor <NUM> to detect that the remaining amount of the rolled sheet <NUM> has reached a predetermined amount.

In <FIG>, the protruding portion <NUM> protrudes toward the positive side in the Y-axis direction with respect to the flapper base portion <NUM>. The protruding portion <NUM> faces the sheet holding unit <NUM>. The detection of the protruding portion <NUM> by the photosensor <NUM> will be described later.

The shape of the sheet holding unit <NUM> is not limited to the example of <FIG>. For example, the sheet holding unit <NUM> may include a plurality of members for holding the sheet.

Returning to <FIG> and <FIG>, the flapper rotation shaft <NUM> is installed along the X-axis at a position on the positive side in the Y-axis direction with respect to the upper cover rotation shaft <NUM> by which the upper cover <NUM> is rotated. Note that, for example, a torsion spring (not shown) is attached to the flapper rotation shaft <NUM>, and the flapper <NUM> is biased by the torsion spring in the direction of the rolled sheet <NUM> accommodated in the storage unit <NUM>.

The platen roller <NUM> is installed along the rear surface side of the upper cover <NUM>. The platen roller <NUM> operates as a conveying unit. The platen roller <NUM> is rotated by a driving force transmitted from a stepping motor (not shown) to pull out the thermal paper <NUM> from the rolled sheet <NUM> stored in the storage unit <NUM> and convey it from the storage unit <NUM>, which is an upstream side, toward the thermal head <NUM>, which is a downstream side.

The thermal head <NUM> is installed along the inner surface of the lower housing <NUM>. The thermal head <NUM> operates as a printing unit. The thermal head <NUM> is in close contact with the platen roller <NUM> in a state where the upper cover <NUM> is closed. The thermal head <NUM> performs printing on the thermal paper <NUM> conveyed by the platen roller <NUM>. The thermal paper <NUM> is conveyed toward the discharge port <NUM> in a state of being sandwiched between the thermal head <NUM> and the platen roller <NUM>.

The thermal head <NUM> has a structure in which a plurality of heating elements are aligned, and performs printing on the thermal paper <NUM> sandwiched between the thermal head <NUM> and the platen roller <NUM> by causing the heating elements corresponding to a printing pattern to generate heat.

The storage unit <NUM> stores the rolled sheet <NUM>, which is the thermal paper <NUM> wound around the roll core <NUM> in a roll shape. The storage unit <NUM> includes the inner wall <NUM> and a recessed portion <NUM>. The rolled sheet <NUM> is accommodated in the storage unit <NUM> in a state of being in contact with the inner wall <NUM>.

The inner wall <NUM> has a wall surface extending to the positive side in the Z-axis direction, and has an inclined surface rising toward the discharge port <NUM> along the positive side in the Y-axis direction. The inner wall <NUM> includes the recessed portion <NUM>.

The recessed portion <NUM> is provided at a position where the rolled sheet <NUM> that has reached a predetermined amount is pressed against the inner wall <NUM> of the storage unit <NUM> by the flapper <NUM>. The recessed portion <NUM> is located in the vicinity of a corner formed by the bottom surface of the housing <NUM> in the vertical position and the bottom surface in the horizontal position. When the rolled sheet <NUM> pressed by the flapper <NUM> reaches the predetermined amount, it is pressed against the recessed portion <NUM>.

The recessed portion <NUM> further includes a convex portion <NUM> (or a step portion). The convex portion <NUM> is provided at an edge of the recessed portion <NUM> on the side close to the thermal head <NUM> so as to form a step on the inner wall <NUM>.

In <FIG>, the rolled sheet <NUM> accommodated in the storage unit <NUM> is supported at three points: a contact point with the flapper <NUM>, a contact point with the recessed portion <NUM>, and a contact point with the inclined surface of the recessed portion <NUM>. Among them, the thermal paper <NUM> is pulled out from the rolled sheet <NUM> at the contact point with the vertical direction of the recessed portion <NUM>. Hereinafter, the contact point between the rolled sheet <NUM> and the vertical side of the recessed portion <NUM> is referred to as an extraction point <NUM>.

The flapper <NUM> is rotatably attached to the upper cover <NUM> by the flapper rotation shaft <NUM>. The rolled sheet <NUM> is pressed against the recessed portion <NUM> or the inner wall <NUM> by being pressed by the flapper <NUM> which rotates clockwise in <FIG> and <FIG>.

When the force applied to the contact point <NUM> between the flapper <NUM> and the rolled sheet <NUM> is F, the force applied to the extraction point <NUM> of the recessed portion <NUM> with the rolled sheet <NUM> is divided into a component force Fa toward the positive side of the Y-axis and a component force Fb toward the negative side of the Z-axis. That is, the rolled sheet <NUM> is pressed against the inner wall <NUM> so as to have a pressing force toward the direction (i.e., Y-axis positive side) in which the thermal paper <NUM> is pulled out. In addition, the flapper <NUM> has a surface that is substantially parallel to the inner wall <NUM> in a state in which the rolled sheet <NUM> that has reached the predetermined amount is pressed.

As a result, the rolled sheet <NUM> is pressed toward the direction in which the thermal paper <NUM> is drawn out at the extraction point <NUM>, regardless of the state in which printing is performed on the thermal paper <NUM> and the state in which printing is not performed. As described above, the flapper <NUM> suppresses the movement of the rolled sheet <NUM> inside the recessed portion <NUM>.

When the rolled sheet <NUM> comes into contact with the convex portion <NUM> (not shown), the rolled sheet <NUM> comes into contact with the convex portion <NUM>. When the convex portion <NUM> and the rolled sheet <NUM> come into contact with each other, movement of the rolled sheet <NUM> inside the recessed portion <NUM> is suppressed.

The thermal paper <NUM> drawn out from the extraction point <NUM> is conveyed in the direction of the arrow B as the platen roller <NUM> rotates. A front surface <NUM> of the thermal paper <NUM> is a printing surface. Printing is performed on the front surface <NUM> of the thermal paper <NUM> by the thermal head <NUM>. The printed thermal paper <NUM> is discharged from the discharge port <NUM>.

The discharge port <NUM> is provided with a cutter (not shown). The user of the thermal printer <NUM> cuts the thermal paper <NUM> that has been discharged after the printing is completed by the cutter.

The rolled sheet <NUM> shown in <FIG> indicates the position of the rolled sheet <NUM> inside the storage unit <NUM> when the rolled sheet <NUM> is a label paper wound without a base sheet. In the case of label paper, the front surface of the label paper is a printing surface, and the back surface is an adhesive layer. When the label paper is held in a state of being sandwiched between the platen roller <NUM> and the thermal head <NUM>, since the back surface of the label paper is adhesive, the rolled sheet <NUM> is held along the inclined surface <NUM>.

The photosensor <NUM> is installed on the inner surface of the upper cover <NUM>. The photosensor <NUM> detects that the remaining amount of the rolled sheet <NUM> has reached a predetermined amount, that is, that the thermal paper <NUM> has run out of paper (i.e., near-end).

The photosensor <NUM> detects a portion of the flapper <NUM> that presses the rolled sheet <NUM> whose remaining amount has reached a predetermined amount, which is displaced by rotation. The photosensor <NUM> is provided at any position where the protruding portion <NUM> can be detected when the flapper <NUM> presses the rolled sheet <NUM> that has reached the predetermined amount. That is, when the remaining amount of the rolled sheet <NUM> has reached the predetermined amount, the photosensor <NUM> overlaps with the protruding portion <NUM> when viewed from the positive side in the Z-axis direction.

The photosensor <NUM> is, for example, a transmissive photosensor in which a light emitter that emits light and a light receiver that receives light are integrated. For example, the photosensor <NUM> is formed in a substantially U-shape, and when viewed from the positive side in the Z-axis direction, the opening of the U-shape is arranged toward the negative side in the Y-axis direction (see <FIG> and <FIG>).

For example, the light emitter is an LED (Light Emitting Diode), and the light receiver is a photodiode or a phototransistor. The light receiver outputs different signals depending on whether the light emitted by the light emitter has been reflected and received.

Next, the positional relationship between the flapper <NUM> and the photosensor <NUM> will be described. <FIG> is an enlarged view of the region C shown in <FIG>. The positional relationship between the flapper <NUM> and the photosensor <NUM> shown in <FIG> indicates a state in which the remaining amount of the rolled sheet <NUM> has reached the predetermined amount.

In <FIG>, the protruding portion <NUM> of the flapper <NUM> is within a detection area of the photosensor <NUM>. The protruding portion <NUM> is within an angular range detectable by the photosensor <NUM> when the flapper <NUM> presses the rolled sheet <NUM> having the predetermined amount or less.

With this configuration, the photosensor <NUM> detects that the remaining amount of the rolled sheet <NUM> has reached the predetermined amount by detecting the protruding portion <NUM>. Then, the thermal printer <NUM> issues a signal that notifies that the remaining amount of the rolled sheet <NUM> has reached the predetermined amount to turn on or blink an indicator such as a lamp or an LED disposed on an outer surface of the lower housing <NUM> or the upper cover <NUM>, for example. Additionally or alternatively, the thermal printer <NUM> can issue a signal that notifies a host computer (not shown) connected thereto via a network interface circuit that the remaining amount of the rolled sheet <NUM> has reached the predetermined amount. Such signals may be issued and output by a controller, a control circuit, or a processor of the thermal printer <NUM> (not shown) for controlling various components of the thermal printer <NUM> including the platen roller <NUM> and the thermal heat <NUM>.

Next, a method in which the photosensor <NUM> detects the remaining amount of the rolled sheet <NUM> will be described. <FIG> and <FIG> are diagrams for explaining a method by which the photosensor <NUM> detects the remaining amount of the rolled sheet <NUM>.

<FIG> shows the positions of the flapper <NUM> and the photosensor <NUM> when the remaining amount of the rolled sheet <NUM> has not reached the predetermined amount, that is, the remaining amount of the rolled sheet <NUM> is sufficiently present. <FIG> shows the positions of the flapper <NUM> and the photosensor <NUM> when the remaining amount of the rolled sheet <NUM> has reached the predetermined amount, that is, the remaining amount of the rolled sheet <NUM> is small.

In the present embodiment, one end of a substantially U-shape of the photosensor <NUM> includes a light emitter <NUM>, and the other end includes a light receiver <NUM>. The light emitter <NUM> emits light <NUM> toward the light receiver <NUM>. Note that the position of the light emitter <NUM> and the position of the light receiver <NUM> may be reversed in implementation.

As shown in <FIG>, when the remaining amount of the rolled sheet <NUM> has not reached the predetermined amount, the light receiver <NUM> receives the light <NUM> emitted from the light emitter <NUM> because there is no obstruction in the opening <NUM> between the light emitter <NUM> and the light receiver <NUM> of the photosensor <NUM>. In this case, the light receiver <NUM> outputs a signal indicating that the light <NUM> emitted from the light emitter <NUM> is received.

As shown in <FIG>, when the remaining amount of the rolled sheet <NUM> has reached the predetermined amount, the protruding portion <NUM> is present in the opening <NUM> of the light emitter <NUM> and the light receiver <NUM> of the photosensor <NUM>. Therefore, the light receiver <NUM> does not receive the light <NUM> emitted from the light emitter <NUM>. In this case, the light receiver <NUM> outputs a signal indicating that the light <NUM> emitted from the light emitter <NUM> is not received.

As described above, the photosensor <NUM> can detect the state when the remaining amount of the rolled sheet <NUM> has reached the predetermined amount by detecting the protruding portion <NUM>. Therefore, the thermal printer <NUM> can detect that the remaining amount of the rolled sheet <NUM> has reached the predetermined value.

The thermal printer <NUM> can notify that the remaining amount of the rolled sheet <NUM> has reached the predetermined amount by turning on or blinking an indicator (not shown). Alternatively, the thermal printer <NUM> can notify a host computer (not shown) connected thereto that the remaining amount of the rolled sheet <NUM> has reached the predetermined amount. The user can prepare the replacement rolled sheet <NUM> in advance after confirming the indicator lit or blinking or the display on the host computer (for example, a liquid crystal display connected to the host computer).

Further, since the protruding portion <NUM> is provided in a certain angular range surrounding the flapper rotation shaft <NUM>, it is possible to continue the detection by the photosensor <NUM> not only when the remaining amount of the rolled sheet <NUM> pressed by the flapper <NUM> has reached the predetermined amount but also when the remaining amount is further reduced. Accordingly, it is possible to prevent the near-end notification from being missed.

Further, in the present embodiment, since the convex portion <NUM> is provided at the edge of the recessed portion <NUM>, when the thermal paper <NUM> is pulled out from the rolled sheet <NUM>, the rolled sheet <NUM> can be hardly pulled out from the recessed portion <NUM>. Thus, the near-end detection of the rolled sheet <NUM> can be accurately performed.

Further, as in the present embodiment, when the flapper <NUM> and the inner wall <NUM> face each other substantially in parallel at the near end of the rolled sheet <NUM>, the near end detection can be accurately performed even if the rolled sheet <NUM> escapes from the recessed portion <NUM>, for example. Such a configuration is also suitable, for example, in a case where the rolled sheet <NUM> is a label paper wound without a base sheet, and the rolled sheet <NUM> is supposed to move toward the thermal head <NUM> at the time of paper conveyance.

As described above, in the thermal printer <NUM> according to the present embodiment, as the flapper <NUM> rotates, the rolled sheet <NUM> is pressed against the inner wall <NUM> of the storage unit <NUM> by pressing in a direction away from the upper cover <NUM>, and the recessed portion <NUM> is provided at a position where the rolled sheet <NUM> that has reached the predetermined amount is pressed by the flapper <NUM>.

Therefore, even in a state where the remaining amount of the rolled sheet <NUM> is small, the thermal printer <NUM> can have a pressing force toward the direction in which the thermal paper <NUM> is pulled out by pressing the rolled sheet <NUM> against the recessed portion <NUM>. Thus, the rolled sheet <NUM> can be accommodated in the storage unit <NUM> even in a state where the remaining amount of the rolled sheet <NUM> is small.

Further, even in a state where the remaining amount of the rolled sheet <NUM> is small, the thermal printer <NUM> accommodates the rolled sheet <NUM> in the storage unit <NUM>, so that the photosensor <NUM> can detect the protruding portion <NUM> included in the flapper <NUM>. Further, the photosensor <NUM> can detect the state when the remaining amount of the rolled sheet <NUM> has reached the predetermined amount by detecting the protruding portion <NUM>. Therefore, the thermal printer <NUM> can detect that the remaining amount of the rolled sheet <NUM> has reached a predetermined value.

Claim 1:
A printer (<NUM>) comprising:
a housing (<NUM>) in which a sheet is stored in a rolled shape;
a head (<NUM>) by which an image is printed on the sheet;
a cover (<NUM>) for an opening of the housing (<NUM>) through which the sheet is set;
a flapper (<NUM>) configured to pivot around an axis (<NUM>) at a first end of the flapper (<NUM>), the axis (<NUM>) being rotatably supported along a rear surface of the cover (<NUM>), the flapper (<NUM>) including:
a surface extending from the first end to a second end of the flapper (<NUM>) and biased to press the stored sheet against the housing (<NUM>), and
a protrusion at the first end of the flapper (<NUM>) that rotates around the axis (<NUM>) as the flapper pivots;
a sensor (<NUM>); and
a controller configured to issue a signal when the protrusion is rotated around the axis (<NUM>) to move into a detection range of the sensor;
wherein the surface of the flapper (<NUM>) is configured to press the stored sheet in a direction away from the cover (<NUM>).