Printer

Provided is a printer capable of enhancing the cutting efficiency of printing paper. A printer, includes a printing unit; a fixed blade; a movable blade provided to be movable relative to the fixed blade, and cut the printing medium with the fixed blade; and a tension mechanism applying a tensional force to the printing medium. The tension mechanism includes a receiving member disposed on the discharge side of the fixed blade; and a pressing member extending from the movable blade toward the discharge side, moving with the movable blade. The pressing member includes a pressing part configured to press the printing medium against the receiving member and move toward the discharge side while holding the printing medium between the pressing part and the receiving member, as the movable blade moves toward the fixed blade.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority of the prior Japanese Application No. 2013-172698, filed on Aug. 22, 2013, the entire contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a printer.

2. Description of the Related Art

There is known a printer provided with a fixed blade fixed on a housing, and a movable blade mounted on the housing to be reciprocally movable relative to the fixed blade for cutting printing paper by the movable blade and the fixed blade (For example, JP2007-38367A, JP2010-099852A).

In cutting a printing paper, the cutting efficiency may be lowered when the printing paper is held between a movable blade and a fixed blade in a relaxed state.

SUMMARY OF THE INVENTION

A printer according to the present invention is for printing on a printing medium. The printer is provided with a printing unit; a fixed blade; a movable blade provided to be movable relative to the fixed blade, and configured to cut printing medium with the fixed blade, and a tension mechanism configured to apply a tensional force to the printing medium.

The tension mechanism includes a receiving member disposed on the discharge side which is a direction in which the printing medium is discharged relative to the fixed blade, for receiving the printing medium; and a pressing member extending from the movable blade toward the discharge side, and configured to move with the movable blade. The pressing member includes a pressing part configured to press the printing medium against the receiving member and move toward the discharge side while holding the printing medium between the pressing part and the receiving member, as the movable blade moves toward the fixed blade.

DETAILED DESCRIPTION

In the following, embodiments of the invention are described in detail based on the drawings.

A configuration of a printer10according to an embodiment of the invention is described referring toFIGS. 1 and 2. In this embodiment, the printer10is a thermal printer configured to print on printing paper P as a printing medium. As illustrated inFIGS. 1 and 2, the width direction of the printer10(or the width direction of printing paper) is referred to as x-axis direction, and the height direction of the printer10is referred to as z-axis direction. Further, in the following description, to simplify the description, the arrow direction of x-axis in the drawings is referred to as a right direction, and the arrow direction of z-axis in the drawings is referred to as an upward direction.

The printer10is provided with a housing14; a printing unit11configured to print on a printing paper P; and a fixed blade12and a movable blade13configured to cut the printing paper P. The printing unit11has a platen15disposed in the housing14and configured to be rotatable in the housing14, and a head16.

The printing paper P is fed from a paper feeding unit (not illustrated) disposed on the feed side of the printing unit11toward a paper discharge port17of the printer10in the direction indicated by the arrow y. In the specification, the upstream side of the printing paper P being fed is referred to as the feed side, and the downstream side thereof is referred to as the discharge side. The platen15is rotatably mounted in the housing14in such a manner as to come into contact with the lower surface of the printing paper P as illustrated in the drawings.

The head16is disposed to face the platen15, and is disposed in the housing14in such a manner as to come into contact with the upper surface of the printing paper P as illustrated in the drawings. The head16is urged toward the platen15by a spring18for holding the printing paper P between the head16and the platen15. The head16includes a heating unit to perform thermal printing on the printing paper P by applying heat to the printing paper P.

The fixed blade12is fixed in the housing14on the discharge side of the printing unit11in such a manner that a blade part of the fixed blade12is directed upward. The movable blade13is disposed on the upper side of the fixed blade12in such a manner that a blade part of the movable blade13is directed downward. The movable blade13is mounted in the housing14to be reciprocally movable in the direction toward the fixed blade12and in the direction away from the fixed blade12. The movable blade13cuts the printing paper P in cooperation with the fixed blade12.

Next, the driving mechanism20for driving the movable blade13in the embodiment is described referring toFIGS. 3 to 6. The driving mechanism20includes a motor21, a pulley22that transmits a rotary movement of a rotary shaft (not illustrated) of the motor21, and a first driving gear23and a second driving gear24that transmit the rotary movement of the motor21via the pulley22. The motor21is fixed in the housing14, and rotates the rotary shaft.

The pulley22includes a first gear22a, a second gear22b, and a belt22cinstalled in mesh with the first gear22aand the second gear22b. The first gear22ais fixed on the rotary shaft of the motor21, and the rotary movement of the motor21is transmitted to the second gear22bvia the first gear22aand the belt22c.

A small gear22dis coaxially mounted on the second gear22b. The first driving gear23meshes with the small gear22don its one side, and meshes with a tooth26fixed on one end of the movable blade13on the other side. The second driving gear24is mechanically linked to the first driving gear23via a shaft25. The second driving gear24meshes with a tooth27fixed on an end of the movable blade13on a side opposite to the side where the tooth26is provided.

As the first driving gear23is rotated by receiving a rotational force from the small gear22d, the second driving gear24is integrally rotated with the first driving gear23via the shaft25. The rotations of the first driving gear23and the second driving gear24are converted into up-and-down movement of the movable blade13via the tooth26and the tooth27. In this way, the driving mechanism20moves the movable blade13in up-and-down directions. In the embodiment, the movable blade13includes a concave-shaped blade13cconfigured so that the height of the movable blade13in up-and-down directions decreases as the movable blade13extends from both ends thereof toward the middle thereof in the width direction.

Referring toFIGS. 1 and 7, the printer10according to the embodiment is provided with a tension mechanism100configured to apply a tensional force to the printing paper P when cutting the printing paper P. The tension mechanism100pulls the printing paper P toward the discharge side in association with the movable blade13when the movable blade13is moving toward the fixed blade12so as to cut the printing paper P.FIG. 7illustrates a state where the printing paper P is cut while the tension mechanism100pulls the printing paper P toward the discharge side.

A configuration of the tension mechanism100in the first embodiment is described referring toFIGS. 8A and 8B. To simplify the understanding, the fixed blade12, the movable blade13, and the tension mechanism100are schematically illustrated inFIGS. 8A and 8B. The tension mechanism100is provided with a receiving member101disposed on the discharge side of the fixed blade12, and a pressing member102mounted on the movable blade13and extending from the movable blade13toward the discharge side.

As illustrated inFIGS. 2 and 7, the receiving member101is fixedly mounted on the housing14at a position of the paper discharge port17of the housing14. As illustrated inFIGS. 8A and 8B, the receiving member101is a stage having a flat upper surface101a, and is configured to support the printing paper P on the upper surface101a.

As will be described later, the pressing member102is configured to move with the movable blade13and hold the printing paper P with the receiving member101. The pressing member102includes an arm1020extending from a surface13aof the movable blade13on the discharge side toward the discharge side and toward the lower side, and a pressing part1021formed at a tip of the arm1020on the discharge side.

The arm1020includes a first part1020afixed on the surface13aof the movable blade13, and a second part1020bextending from the lower end of the first part1020a. The first part1020aof the arm1020is fixed on the surface13aby a fixing tool103. The pressing part1021is formed at a tip of the second part1020bon the discharge side so as to face the printing paper P and be bent into an L-shape.

In this embodiment, the pressing member102is constituted of a flat resilient member. The first part1020aand the second part1020bof the arm1020are defined by bending the resilient member along a bending line L1. Further, the pressing part1021is formed by bending a tip of the second part1020bon the discharge side along a bending line L2.

Next, a function of the tension mechanism100in the embodiment is described referring toFIGS. 8A and 8B, andFIGS. 9A and 9B. When cutting the printing paper P, the driving mechanism20moves the movable blade13downward toward the fixed blade12. Then, the movable blade13comes into contact with the upper surface of the printing paper P. On the other hand, the pressing part1021of the tension mechanism100comes into contact with the printing paper P before the movable blade13and the fixed blade12cut the printing paper P (e.g. before the movable blade13comes into contact with the printing paper P).

When cutting the printing paper P, the movable blade13is moved further downward from the state illustrated inFIGS. 8A and 8Bto the state illustrated inFIGS. 9A and 9B. As the movable blade13is moved downward, the pressing part1021presses the printing paper P against the upper surface101aof the receiving member101, and is moved toward the discharge side as illustrated by the arrow D0inFIG. 8Bwhile holding the printing paper P between the pressing part1021and the receiving member101. The state illustrated inFIGS. 9A and 9Bcorresponds to the state illustrated inFIG. 7.

As the pressing part1021is moved toward the discharge side as described above, the arm1020is bent along the bending line L1in such a manner that the angle between the first part1020aand the second part1020bdecreases, and the second part1020bis bent. In this way, the arm1020is resiliently deformed in response to downward movement of the movable blade13after the pressing part1021comes into contact with the printing paper P. The resiliently deformed arm1020causes the pressing part1021to press against the printing paper P by a restoring force of the arm1020.

Thus, the arm1020functions as a plate spring capable of generating a resilient force by being resiliently deformed in response to downward movement of the movable blade13. As illustrated inFIGS. 8A and 8B, the pressing part1021is moved toward the discharge side while pressing the printing paper P against the receiving member101by a pressing force F1which is a force component acting in a direction perpendicular to the upper surface101aof the receiving member101.

By the aforementioned operation, the tension mechanism100in the embodiment can hold the printing paper P between the receiving member101and the pressing member102and pull the printing paper P toward the discharge side, when cutting the printing paper P. Therefore, it is possible to cut the printing paper P by the movable blade13and the fixed blade12in a state where the printing paper P is strained. This is advantageous in enhancing the cutting efficiency of printing paper P.

Further, according to the embodiment, it is possible to apply a tensional force to the printing paper P by the pressing member102of a simplified structure and constituted of one resilient member, without using a large device for applying a tensional force to the printing paper P. This is advantageous in enhancing the cutting efficiency of printing paper P, with saving the production cost.

A tension mechanism200according to a second embodiment of the invention is described referring toFIGS. 10A to 13B. Substantially the same elements as those in the first embodiment are indicated with the same numerals, and a detailed description thereof is omitted herein.

A configuration of the tension mechanism200of the second embodiment is described referring toFIGS. 10A and 10B. The tension mechanism200is provided with a receiving member101; a pressing member202pivotally attached to the movable blade13; and a restricting unit203configured to restrict pivotal movement of the pressing member202.

The pressing member202has an arm2020pivotally supported on the movable blade13by a shaft204and extending from the movable blade13toward the discharge side and toward the lower side; and a pressing part1021formed at a tip of the arm2020on the discharge side. The arm2020includes an extension portion2021extending toward the feed side relative to the movable blade13. A hollow holding part2022for holding the shaft204extending along x-axis is formed between the arm2020and the extension portion2021.

The shaft204is fixed on the movable blade13in such a manner as to extend along x-axis within an opening13dformed in the middle part of the movable blade13, and is inserted through the holding part2022. Thus, the pressing member202is pivotally supported on the movable blade13via the shaft204so as to rotate around x-axis. As well as the first embodiment, the pressing member202is constituted of a flat resilient member. A pressing part1021comes into contact with printing paper P is formed by bending a tip of the arm2020into an L-shape.

The restricting unit203includes a first restricting part2031extending from the movable blade13toward the feed side, and a second restricting part (an example of a return part)2032that comes into contact with the arm2020on the discharge side of the movable blade13. To simplify the understanding, inFIG. 10AandFIG. 13A, the second restricting part2032is indicated by the dotted line, and inFIG. 11AandFIG. 12A, the illustration of the second restricting part2032is omitted.

The first restricting part2031includes a first part2031afixed on a surface13bof the movable blade13on the feed side, a second part2031bextending from the upper end of the first part2031atoward the feed side and toward the upper side, and a convex part2031cformed at a tip of the second part2031bon the feed side. The first restricting part2031has substantially the same width as the pressing member202, and is constituted of a flat resilient member.

The first part2031aand the second part2031bare defined by bending one resilient member constituting the first restricting part2031along a bending line L3. The convex part2031cof the first restricting part2031is formed by bending a tip of the second part2031bon the feed side into such a U-shape as to be convex toward the discharge side when viewed from x-axis direction. Further, a concave part2031dto be concave toward the feed side when viewed from x-axis direction is formed between the second part2031band the convex part2031c.

On the other hand, the second restricting part2032of the restricting unit203is mounted in the housing14of a printer10, and extends from the housing14downward to a position upwardly spaced from the fixed blade12by a predetermined distance. The second restricting part2032comes into contact with the arm2020at a predetermined height position, as will be described later.

A function of the tension mechanism200in the embodiment is described referring toFIG. 10AtoFIG. 13B. As illustrated inFIGS. 10A and 10B, the extension portion2021of the arm2020is disposed at a position above the convex part2031cof the first restricting part2031before the printing paper P is cut. When cutting the printing paper P, the movable blade13is moved downward toward the fixed blade12from the state illustrated inFIGS. 10A and 10Bto the state illustrated inFIGS. 11A and 11B.

As the movable blade13is moved downward, the pressing part1021holds the printing paper P between the pressing part1021and the receiving member101, and presses the printing paper P against the upper surface101aof the receiving member101. Then, the pressing part1021receives, from the receiving member101, force acting in a direction opposite to the direction of force of pressing the printing paper P against the receiving member101. Due to this force, the arm2020is urged to pivot relative to the movable blade13in a first direction D1(seeFIG. 10B) around the shaft204, in other words, in such a direction that the pressing part1021is released from the printing paper P.

On the other hand, the pivotal movement of the arm2020in the first direction D1is restricted, because the extension portion2021of the arm2020is in contact with the convex part2031cof the first restricting part2031at the upper part of the convex part2031c. According to this configuration, as the movable blade13is moved downward, the pressing part1021can press the printing paper P against the upper surface101aof the receiving member101, and is moved toward the discharge side while holding the printing paper P between the pressing part1021and the receiving member101.

Further, as illustrated inFIGS. 11A and 11B, as the movable blade13is moved further downward, the arm2020in contact with the upper surface101avia the printing paper P is resiliently deformed into a curved shape. The arm2020presses the pressing part1021against the receiving member101in response to resilient deformation of the arm2020. In this way, the pressing part1021is moved toward the discharge side, while pressing the printing paper P against the receiving member101with the pressing force F1, by the action of the first restricting part2031and the arm2020.

By such an operation, the tension mechanism200can hold the printing paper P between the receiving member101and the pressing member202, and pull the printing paper P toward the discharge side when cutting the printing paper P. As a result, it is possible to cut the printing paper P by the movable blade13and the fixed blade12in a state where the printing paper P is strained. This is advantageous in enhancing the cutting efficiency of printing paper P.

On the other hand, as the movable blade13is moved downward as illustrated inFIG. 11B, the extension portion2021of the arm2020presses the upper part of the convex part2031cof the first restricting part2031with a force F2. Upon receiving the force F2, the first restricting part2031is gradually deformed resiliently, and the position of the convex part2031cis gradually displaced toward the feed side.

When the movable blade13is moved further downward after cutting the printing paper P, and crosses over a predetermined first position, the extension portion2021climbs over the convex part2031c, and the engagement between the extension portion2021and the convex part2031cis released. As a result, the arm2020is pivotally moved slightly in the first direction D1, and then the extension portion2021is accommodated in the concave part2031dformed between the second part2031band the convex part2031c. This state is illustrated inFIG. 12B. As illustrated inFIG. 12C, the pressing part1021of the pressing member202is released from the printing paper P by pivotal movement of the arm2020in the first direction D1.

After finishing the cutting operation of the printing paper P, the movable blade13is then moved upward from the position illustrated inFIGS. 12A to 12Cso as to move away from the fixed blade12, in order to return to the initial position before the cutting operation is started. When the movable blade13reaches a predetermined second position above the first position, as illustrated inFIGS. 13A and 13B, the arm2020of the pressing member202comes into contact with the lower end of the second restricting part2032on the discharge side of the movable blade13. Pivotal movement of the arm2020in the first direction D1is restricted by the second restricting part2032.

When the movable blade13is moved further upward from the position illustrated inFIGS. 13A and 13B, the arm2020tends to pivotally move in a second direction D2opposite to the first direction D1around the shaft204by being pressed by the second restricting part2032. However, the pivotal movement of the arm2020in the second direction D2is restricted, because the extension portion2021is engaging with the convex part2031c. As illustrated inFIG. 13B, the extension portion2021presses the lower part of the convex part2031cof the first restricting part2031with a force F3. Upon receiving the force F3, the first restricting part2031is gradually deformed resiliently, and the position of the convex part2031cis gradually displaced toward the feed side.

When the movable blade13is further moved upwardly over the second position, the extension portion2021climbs over the convex part2031c, and the engagement between the extension portion2021and the convex part2031cis released. As a result, the arm2020pivotally moves in the second direction D2, and the arm2020returns to the position illustrated inFIGS. 10A and 10B.

According to the tension mechanism200in this embodiment, it is possible to prevent the cut printing paper P from being pulled to the feed side by the pressing part1021after the printing paper P is cut. In particular, as illustrated inFIG. 12C, the pressing part1021of the second embodiment is released from the printing paper P after the printing paper P is cut but before the movable blade13moves upward. In other words, a force of pressing the printing paper P against the receiving member101is released. The movable blade13moves upward while the pressing force against the printing paper P is released. Therefore, according to the embodiment, the pressing part1021will not move toward the feed side with holding the printing paper P between the pressing part1021and the receiving member101while the movable blade13is moving upward. This makes it possible to prevent the cut printing paper P from returning to the feed side, and to prevent obstruction of a feeding operation of printing paper P by the returned printing paper P in a subsequent cutting operation of printing paper P.

Further, it is possible to prevent the cut printing paper P from returning according to the embodiment by selectively allowing pivotal movement of the arm2020in the first direction D1or in the second direction D2utilizing resilient deformation of the first restricting part2031. This is advantageous in preventing the printing paper P from returning without the need of a complicated device.

A configuration of a tension mechanism300according to a third embodiment of the invention is described referring toFIGS. 14A and 14B, andFIGS. 15A and 15B. Substantially the same elements as those in the first and second embodiments are indicated with the same numerals, and a detailed description thereof is omitted herein.

The tension mechanism300is provided with the receiving member101; the pressing member202pivotally attached to the movable blade13; and a torsion spring303disposed between the movable blade13and the arm2020of the pressing member202. The pressing member202is pivotally supported on the movable blade13via the shaft204inserted in the holding part2022.

As illustrated inFIG. 15B, the torsion spring303includes a main body303a, an end part303bextending from the main body303ain one direction, and an end part303cextending from the main body303ain the other direction. In the embodiment, two torsion springs303are disposed on left and right ends of the pressing member202.

As illustrated inFIG. 15A, the first torsion spring303is disposed between the left edge of the arm2020and a left wall surface defining an opening13dof the movable blade13. The left end of the shaft204is inserted to the main body303aof the first torsion spring303. One end part303bof the first torsion spring303engages the surface13aof the movable blade13on the discharge side, while the other end part303cof the first torsion spring303engages the arm2020.

Similarly, the second torsion spring303is disposed between the right edge of the arm2020and the right wall surface defining the opening13dof the movable blade13. The right end of the shaft204is inserted to the main body303aof the second torsion spring303. One end part303bof the second torsion spring303engages the surface13aof the movable blade13on the discharge side, while the other end part303cof the second torsion spring303engages the arm2020.

Next, a function of the tension mechanism300in the embodiment is described referring toFIG. 14AtoFIG. 17B. As the movable blade13moves downward toward a fixed blade12from the position illustrated inFIGS. 14A and 14Bso as to cut the printing paper P, the pressing part1021moves toward the discharge side while pressing the printing paper P against the upper surface101aof the receiving member101.

During this operation, the pressing part1021receives, from the receiving member101, a force in a direction opposite to the direction of force of pressing the printing paper P against the receiving member101. Due to this force, the arm2020pivotally moves relative to the movable blade13in the first direction D1around the shaft204in association with downward movement of the movable blade13, and is brought to the state illustrated inFIGS. 16A and 16B.

As the arm2020pivotally moves in the first direction D1, the torsion springs303disposed between the movable blade13and the arm2020urge the arm2020in the second direction D2opposite to the first direction D1. As illustrated inFIGS. 17A and 17B, when the arm2020is pivotally moving from the position illustrated inFIG. 17Ato the position illustrated inFIG. 17Bin association with downward movement of the movable blade13, the torsion springs303resiliently deform in response to pivotal movement of the arm2020.

As illustrated inFIG. 17B, the torsion springs303generate a resilient restoring force in the second direction D2in response to resilient deformation of the arm2020, and urge the arm2020in the second direction D2by the generated resilient restoring force. By the urging force applied from the torsion springs303to the arm2020, the pressing part2021presses the printing paper P against the upper surface101aof the receiving member101. As the movable blade13moves toward the fixed blade12, the pressing part1021moves toward the discharge side, while holding the printing paper P between the pressing part1021and the receiving member101.

By the above operation, the tension mechanism300in the embodiment can pull the printing paper P toward the discharge side, while holding the printing paper P between the receiving member101and the pressing member202when cutting the printing paper P. Thereby, it is possible to cut the printing paper P by the movable blade13and the fixed blade12in a state where the printing paper P is strained. This is advantageous in enhancing the cutting efficiency of printing paper P.

In addition, according to the embodiment, it is possible to press the pressing part1021against the upper surface101aof the receiving member101so as to hold the printing paper P therebetween by utilizing a resilient restoring force of the torsion springs303, without using a complicated device. This is advantageous in enhancing the cutting efficiency of printing paper P with saving the production cost.

A configuration of a tension mechanism400according to a fourth embodiment of the invention is described referring toFIGS. 18A and 18B, andFIGS. 19A and 19B. Substantially the same elements as those in the first to third embodiments are indicated with the same numerals, and a detailed description thereof is omitted herein. The tension mechanism400of the fourth embodiment is provided with a receiving member101and a pressing member402.

The pressing member402has a roller4020, and a first arm4021and a second arm4022rotatably supports the roller4020at the left and right sides of the roller4020. As illustrated inFIGS. 19A and 19B, the roller4020is in a cylindrical shape with a cylindrical outer peripheral surface4020a, and has a center hole4020bextending through the roller4020along the left-and-right direction (i.e. x-axis direction).

The roller4020has a void S recessed in the right direction from a left end surface4020c. A concave-convex part4020dis formed on the inner surface of the roller4020defining the void S. Likewise, the roller4020has a void (not illustrated) recessed in the left direction from a right end surface4020e, and a concave-convex part (not illustrated) having substantially the same shape as the concave-convex part4020dis formed on the inner surface of the roller4020defining the void.

The first arm4021is disposed on the left side of the roller4020. The first arm4021has a first part4021afixed on the surface13aof the movable blade13on the discharge side, a second part4021bextending from the lower end of the first part4021atoward the discharge side and toward the lower side, and a shaft4021cextending from a tip of the second part4021btoward the right direction.

The right end of the shaft4021cis rotatably inserted in the center hole4020b. A claw4021dprojecting from the shaft4021cin one direction is formed on the shaft4021c. The first part4021aand the second part4021bare defined by bending one resilient rod member along a bending line L4.

The second arm4022is disposed on the right side of the roller4020. As well as the first arm4021, the second arm4022has a first part4022afixed on the surface13aof the movable blade13on the discharge side, a second part4022bextending from the lower end of the first part4022atoward the discharge side and toward the lower side, and a shaft4022cextending from a tip of the second part4022btoward the left direction.

The left end of the shaft4022cis rotatably inserted in the center hole4020b. Further, a claw4022dis formed on the shaft4022c. The first part4022aand the second part4022bare defined by bending one resilient rod member along a bending line L5.

As illustrated inFIG. 19A, in a state where the pressing member402is assembled, the concave-convex part4020dformed on the left end of the roller4020and the claw4021dformed on the first arm4021come into contact with each other. The concave-convex part4020dand the claw4021dare configured to allow the roller4020to rotate without engaging each other when the roller4020is rotated in the direction D3around the shaft parts4021cand4022c.

On the other hand, when the roller4020is rotated in a direction D4opposite to the direction D3around the shaft4021cand4022c, the concave-convex part4020dand the claw4021dengage each other, and the rotation of the roller4020in the direction D4is restricted. The claw4021dand the concave-convex part4020dconstitute a one-way clutch configured to allow the roller4020to rotate only in the direction D3.

Likewise, the concave-convex part formed on the right end of the roller4020, and the claw4022dformed on the second arm4022also constitute a one-way clutch configured to allow the roller4020to rotate only in the direction D3. The functions of the one-way clutch will be described later.

Next, a function of the tension mechanism400in the embodiment is described referring toFIG. 18A to 21B. When the movable blade13moves from the position illustrated inFIGS. 18A and 18Bto the position illustrated inFIGS. 20A and 20Bso as to cut the printing paper P, the roller4020comes into contact with the printing paper P. When the movable blade13moves further downward from the position illustrated inFIGS. 20A and 20Bto the position illustrated inFIGS. 21A and 21B, the roller4020is moved toward the discharge side, while pressing the printing paper P against the upper surface101aof the receiving member101in association with movement of the movable blade13.

During this operation, the roller4020tries to move toward the discharge side with rotating in the direction D4. However, according to the embodiment, rotation of the roller4020in the direction D4is restricted by a one-way clutch constituted of the convex part4021d(4022d) and the concave-convex part4020d. Therefore, the roller4020moves toward the discharge side in association with downward movement of the movable blade13in a state where rotation of the roller4020is restricted. Thereby, when the roller4020is moving toward the discharge side, a frictional force is generated between the roller4020and the printing paper P. This allows the roller4020to effectively press the printing paper P against the receiving member101.

As the roller4020moves toward the discharge side, the first arm4021and the second arm4022are bent along the bending lines L4and L5in such a manner as to decrease the angle between the first part4021a(4022a) and the arm4021b(4022b), and also the arms4021band4022bare resiliently deformed.

The first arm4021and the second arm4022are resiliently deformed in association with downward movement of the movable blade13after the roller4020comes into contact with the printing paper P, whereby the roller4020is pressed against the printing paper P. Thus, the first arm4021and the second arm4022function as a plate spring capable of generating a resilient force by being resiliently deformed in response to downward movement of the movable blade13.

As a result, the roller4020moves toward the discharge side while pressing the printing paper P against the receiving member101with the pressing force F1which is a force component acting in a direction perpendicular to the upper surface101aof the receiving member101, as illustrated inFIGS. 20A and 20B. Thus, in this embodiment, the roller4020functions as a pressing part configured to press the printing paper P against the receiving member101.

By the above operation, the tension mechanism400in the embodiment holds the printing paper P between the receiving member101and the pressing member402and pulls the printing paper P toward the discharge side when cutting the printing paper P. Therefore, it is possible to cut the printing paper P by the movable blade13and the fixed blade12in a state in which the printing paper P is strained. This is advantageous in enhancing the cutting efficiency of printing paper P.

In addition, according to the embodiment, providing the one-way clutch as described above makes it possible to prevent the cut printing paper P from returning toward the feed side. This operation is described in the following. After finishing the cutting operation of the printing paper P, the movable blade13is moved upward away from the fixed blade12from the position illustrated inFIGS. 21A and 21Bto the position illustrated inFIGS. 18A and 18Bso as to return to the initial position before the cutting operation is started.

As the movable blade13moves upward, the roller4020in contact with the upper surface101avia the printing paper P tries to move toward the feed side with rotating in the direction D3. The one-way clutch allows the roller4020to rotate in the direction D3. Therefore, there is no likelihood that a frictional force is generated between the roller4020and the printing paper P, since the roller4020can rotate in the direction D3when the roller4020is moving toward the feed side. This makes it possible to prevent the printing paper P from returning toward the feed side while the movable blade13is moved upward.

Various shapes are applicable to the roller4020. Rollers in other embodiments are described referring toFIGS. 22A and 22B. A roller4030illustrated inFIG. 22Ais formed such that a middle part4031of the roller4030has a larger diameter than the diameter of left and right ends thereof. The diameter of an outer peripheral surface4032of the roller4030gradually increases, as the roller4030extends from a left end surface4033toward the middle part4031; and gradually decreases, as the roller4030extends from the middle part4031toward a right end surface4034. As well as the roller4020, a concave-convex part4035is formed on the inner side of the left end of the roller4030. Likewise, a concave-convex part (not illustrated) is formed on the inner side of the right end of the roller4030.

The roller4030illustrated inFIG. 22Acan locally press the printing paper P against the receiving member101in a smaller region, because the roller4030comes into contact with the printing paper P at the middle part4031. This is advantageous in preventing formation of creases or wrinkles on the printing paper P when the printing paper P is pulled toward the discharge side by the roller4030. Further, it is possible to prevent leftward oblique movement or rightward oblique movement of the roller4030relative to the printing paper P while the roller4030is moved relative to the printing paper P toward the discharge side.

A roller4040illustrated inFIG. 22Bis formed such that a middle part4041of the roller4040has a smaller diameter than the diameter of left and right ends thereof. The diameter of an outer peripheral surface4042of the roller4040gradually decreases, as the roller4040extends from a left end surface4043toward the middle part4041; and gradually increases, as the roller4040extends from the middle part4041toward a right end surface4044. Further, a concave-convex part4045is formed on the inner side of the left end of the roller4040. Likewise, a concave-convex part (not illustrated) is formed on the inner side of the right end of the roller4040.

The roller4040illustrated inFIG. 22Bcomes into contact with the printing paper P at left and right ends thereof. The roller4040can also locally press the printing paper P against the receiving member101in a smaller region, thereby it is possible to prevent formation of creases or wrinkles on the printing paper P. Further, it is also possible to prevent leftward oblique movement or rightward oblique movement of the roller4040relative to the printing paper P while the roller4040is moved relative to the printing paper P toward the discharge side.

Next, a configuration of a printer30in a fifth embodiment of the invention is described referring toFIGS. 23A and 23B. Substantially the same elements as those in the first to fourth embodiments are indicated with the same numerals, and a detailed description thereof is omitted herein. The printer30is provided with a fixed blade12; a movable blade13; a tension mechanism100including a receiving member101and a pressing member102; and a printing paper suppressing member31disposed on the discharge side of the movable blade13.

In this embodiment, two printing paper suppressing members31are disposed on left and right ends of the pressing member102. The printing paper suppressing member31has a first arm31afixed on a surface13aof the movable blade13on the discharge side, a second arm31bextending downward from a tip of the first arm31aon the discharge side, and a spring31cmounted on the lower end of the second arm31band configured to be resiliently deformable in up-and-down directions (i.e. z-axis direction).

The first arm31aand the second arm31bare made of a rigid material such as iron. The first arm31aextends from the surface13aof the movable blade13on the discharge side toward the discharge side. As illustrated inFIGS. 23A and 23B, the spring31cis disposed such that the lower end of the spring31cis located at a position below a pressing part1021in a state wherein both of the pressing part1021and the spring31cdo not come into contact with the printing paper P. Further, the spring31cis disposed to come into contact with the top surface of the printing paper P in a direction perpendicular thereto.

Next, a function of the printing paper suppressing member31in the embodiment is described referring toFIGS. 23A to 26B. When the movable blade13is moved downward from the position illustrated inFIGS. 23A and 23Bso as to cut the printing paper P, the lower end of the spring31ccomes into contact with the printing paper P before the pressing part1021comes into contact with the printing paper P, as illustrated inFIGS. 24A and 24B. As the movable blade13is moved downward from this position, the spring31cis compressed in up-and-down directions, whereby the printing paper P is held between the spring31cand the receiving member101.

When the movable blade13is moved downward to the position illustrated inFIGS. 25A and 25B, the pressing part1021comes into contact with the printing paper P. As the movable blade13is moved further downward from the position illustrated inFIGS. 25A and 25Bto the position illustrated inFIGS. 26A and 26B, the tension mechanism100pulls the printing paper P toward the discharge side, and the printing paper P is cut by the movable blade13and the fixed blade12in a state wherein the printing paper P is strained. During this operation, the printing paper suppressing member31holds the printing paper P between the printing paper suppressing member31and the receiving member101by the action of the spring31c.

After cutting the printing paper P, the movable blade13is moved upward from the position illustrated inFIGS. 26A and 26Bto the position illustrated inFIGS. 25A and 25B. During this operation, the pressing part1021is moved toward the feed side, while holding the printing paper P between the pressing part1021and the receiving member101. Specifically, the tension mechanism100tries to pull the cut printing paper P toward the feed side during this operation.

In the embodiment, the printing paper suppressing member31suppresses the printing paper P while holding the printing paper P between the printing paper suppressing member31and the receiving member101by the action of the spring31c. This could prevent returning of the cut printing paper P toward the feed side by the tension mechanism100.

When the movable blade13is moved upward to the position illustrated inFIGS. 24A and 24B, the pressing part1021is released from the printing paper P before the spring31cis released from the printing paper P. Subsequently, when the movable blade13is moved upward to the position illustrated inFIGS. 25A and 25B, the spring31cis released from the printing paper P. In this way, the printing paper suppressing member31securely suppresses the printing paper P until the force of pulling the cut printing paper P toward the feed side by the tension mechanism100is released.

Next, a configuration of a tension mechanism500according to another embodiment of the invention is described referring toFIGS. 27A and 27B. Substantially the same elements as those in the first to fifth embodiments are indicated with the same numerals, and a detailed description thereof is omitted herein. The tension mechanism500is provided with a pressing member102, and a receiving member501in the embodiment.

The receiving member501is disposed on the discharge side of the fixed blade12. The receiving member501has, on a feed side end thereof, a convex part501bprojecting upward toward the printing paper P from an upper surface501a. Further, a concave part501copened toward the discharge side is formed in a discharge side of the convex part501b.

Next, a function of the tension mechanism500in the embodiment is described referring toFIGS. 27A to 27C, andFIGS. 28A to 28C. When the movable blade13is moved from the position illustrated inFIGS. 27A to 27Cto the position illustrated inFIGS. 28A to 28Cso as to cut the printing paper P, the pressing member102pulls the printing paper P toward the discharge side in cooperation with the receiving member501. Then, the fixed blade12and the movable blade13cut the printing paper P.

In the embodiment, the convex part501bincluding the concave part501cis formed on the feed side end of the receiving member501. When a cutting operation is finished, an end of the cut printing paper P is accommodated in the concave part501c, as illustrated inFIG. 28C. This makes it possible to prevent the cut printing paper P from moving toward the feed side.

According to the above configuration, it is possible to prevent the cut printing paper P from returning toward the feed side by the pressing member102, as the movable blade13is moved upward after a cutting operation of printing paper P is finished. This is advantageous in preventing obstruction of a feeding operation of printing paper P by the cut and returned printing paper P in a succeeding cutting operation of printing paper P.

The movable blade may be disposed on the feed side or on the discharge side of the fixed blade. Further, in the foregoing embodiments, a receiving member is fixedly mounted in a housing. However, the invention is not limited to the above. A receiving member may be mounted in a housing on the feed side or on the discharge side to be reciprocally movable, and the receiving member may be configured to be moved toward the discharge side, while holding the printing paper in cooperation with a pressing part, as the movable blade is moved downward in cutting the printing paper.

Further, in the foregoing embodiments, it is exemplified that the upper surface of a receiving member is a flat surface. Alternatively, the upper surface of a receiving member may be a curved surface. For instance, the upper surface of a receiving member may be a curved surface such that the upper surface is curved upward with a predetermined curvature radius, as the receiving member extends toward the discharge side.

Further, in the foregoing embodiments, it is exemplified that a roller is mounted on a first arm and a second arm. However, the invention is not limited to the above. A roller may be replaced by the pressing part described inFIGS. 8A to 17B, and the pressing part may be mounted on the arm described inFIGS. 8A to 17B. Further, a roller may have an outer peripheral surface, for example, having a concave-convex shape, other than the shapes illustrated inFIGS. 19A and 19B, andFIGS. 22A and 22B.

The invention has been described by way of the embodiments of the invention. The foregoing embodiments, however, do not limit the invention defined in the claims. Further, it is obvious to those skilled in the art to add a variety of modifications or improvements to the embodiments. It is obvious that such modifications or improvements are also included in the technical scope of the invention, as defined in the claims of the invention.