Thermal printer

A thermal printer of the present invention includes: a thermal head; a platen roller disposed to face the thermal head; a first path that guides a recording paper drawn from a recording paper roll to one entrance of a gap between the thermal head and the platen roller such that a first main surface of the recording paper is on the thermal head side; a second path that guides the recording paper drawn from the recording paper roll to the other entrance of the gap between the thermal head and the platen roller such that a second main surface of the recording paper is on the thermal head side; and a switch guide that switches between the first path and the second path.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a thermal printer and more particularly to a thermal printer that performs double-sided printing.

2. Description of the Background Art

Thermal printers (also referred to as thermal transfer printers or sublimation printers) are known that have a function of performing printing on both sides of recording paper, the thermal printers thermally transferring ink from an ink sheet to the recording paper for printing. Japanese Patent Application Laid-Open No. 2011-93255 discloses a technique for reversing a rolled recording medium by a reversal means to perform printing on both sides of the recording paper.

With a technique disclosed in Japanese Patent Application Laid-Open No. 2011-110789, recording paper drawn from a rolled recording medium to be cut is guided into a gap between a thermal head and a platen roller in one direction for printing on one main surface of the recording paper. Next, the recording paper is turned upside down and is guided into the gap between the thermal head and the platen roller in the other direction for printing on the other main surface of the recording paper.

The technique disclosed in Japanese Patent Application Laid-Open No. 2011-93255 has the reversal means of reversing the rolled recording medium, resulting in an increased size of the device. Moreover, the reversal means makes an inner mechanism complex, resulting in an increased manufacturing cost.

The technique disclosed in Japanese Patent Application Laid-Open No. 2011-110789 transports, to the inside of the thermal printer, the recording paper drawn from the rolled recording medium to be cut, so that rollers for transporting the recording paper are needed to be disposed at relatively narrow intervals, resulting in the increased number of components.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a thermal printer capable of performing double-sided printing in a simple configuration.

A thermal printer of the present invention includes: a thermal head; a platen roller disposed to face the thermal head; a first path that guides a recording paper drawn from a recording paper roll to one entrance of a gap between the thermal head and the platen roller such that a first main surface of the recording paper is on the thermal head side; a second path that guides the recording paper drawn from the recording paper roll to the other entrance of the gap between the thermal head and the platen roller such that a second main surface of the recording paper is on the thermal head side; and a switch guide that switches between the first path and the second path.

The thermal printer of the present invention can perform double-sided printing in the simple configuration since the two paths, namely, the first path and the second path are provided and can be switched therebetween by the switch guide, the first path and the second path respectively guiding the first main surface and the second main surface of the recording paper drawn from the recording paper roll to the gap between the thermal head and the platen roller so as to be on the thermal head side.

DESCRIPTION OF THE PREFERRED EMBODIMENT

First Preferred Embodiment

FIG. 1is a diagram showing a configuration of a thermal printer100according to a preferred embodiment of the present invention.FIG. 2is a diagram illustrating a transport path of recording paper in the thermal printer100inFIG. 1. As shown inFIG. 1, the thermal printer100includes a thermal head1and a platen roller6disposed to face the thermal head1. Moreover, the thermal printer100includes an ink sheet winding bobbin3that winds an ink sheet5and an ink sheet unwinding bobbin4that unwinds the ink sheet5. A recording paper roll2in which recording paper2ais rolled up in a roll shape is set in the thermal printer100.

As shown inFIG. 2, the thermal printer100includes a guide path30athat guides the recording paper2adrawn from the recording paper roll2to a switch guide20. The thermal printer100includes a first path30bthat guides a first main surface (namely, back side) of the recording paper2ato one entrance of a gap between the thermal head1and the platen roller6so as to be on the thermal head1side. The thermal printer100includes a second path30cthat guides a second main surface (namely, front side) of the recording paper2adrawn from the recording paper roll2to the other entrance of the gap between the thermal head1and the platen roller6so as to be on the thermal head1side.

The thermal printer100further includes the switch guide20that switches between the first path30band the second path30c. The switch guide20will be described below.

The thermal printer100further includes an auxiliary guide21that supports the transport path of the recording paper2a. The auxiliary guide21will be described below.

The thermal printer100further includes a housing path30dthat houses the recording paper2aguided to the one entrance of the gap between the thermal head1and the platen roller6from the first path30bfor printing. The housing path30dis curved in the same direction as the winding direction of the recording paper roll2.

The thermal printer100further includes an ejection path30ethat guides the recording paper2ato an ejection opening16, the recording paper2ahaving passed through the second path30c. The ejection opening16is provided with a cutter16athat cuts the recording paper2a. In the preferred embodiment, the ejection path30ehas a distance greater than an effective print length in a unit screen of the ink sheet5used in the thermal printer100. Here, the distance of the ejection path30eis the distance of the transport path from the gap between the thermal head1and the platen roller to the ejection opening16.

A yellow (Y) region in the unit screen, a magenta (M) region in the unit screen, a cyan (C) region in the unit screen, and an overcoat (OP) region in the unit screen are disposed in the stated order as one group that is repeatedly disposed to form the ink sheet5. Margins (for example, 10 mm) that are not used for printing are provided at both ends of the ink sheet5in a longitudinal direction in each unit screen. A region except for the margins in each unit screen is an effective print region used for printing. The length of the effective print region in the longitudinal direction of the ink sheet5in each unit screen is referred to as the effective print length.

The guide path30aincludes a paper feed roller9that transports the recording paper2aand a pinch roller10that faces the paper feed roller9. A paper feed motor9adrives the paper feed roller9. A cam, which is not shown, changes a position of the pinch roller10between a state where the pinch roller10is pressed against the paper feed roller9and a state where the pinch roller10is kept a distance from the paper feed roller9. A motor rotates the cam, the motor and the cam not being shown.

The guide path30aincludes guide rollers29a,29b,29c,29d,29e,29f,29gthat smoothly transport the recording paper2a. A first sensor50ais provided upstream of the switch guide20in the guide path30a.

The guide path30aincludes a dust removing roller13aand a dust removing roller13b. The dust removing rollers13aand13bare made of, for example, silicon and remove dust adhering to the recording paper2a.

The first path30bincludes a paper feed roller11that transports the recording paper2aand a pinch roller12that faces the paper feed roller11. A paper feed motor9acommon to the paper feed roller9rotates the paper feed roller11. A cam, which is not shown, changes a position of the pinch roller12between a state where the pinch roller12is pressed against the paper feed roller11and a state where the pinch roller12is kept a distance from the paper feed roller11. A motor rotates the cam, the motor and the cam not being shown.

The first path30bincludes guide rollers29h,29i,29j,29nthat smoothly transport the recording paper2a. A second sensor50bis provided, for example, between the guide roller29iand the guide roller29jin the first path30b.

The second path30cincludes a grip roller7that transports the recording paper2aand a pinch roller8that faces the grip roller7. A transport motor7arotates the grip roller7. A cam, which is not shown, changes a position of the pinch roller8between a state where the pinch roller8is pressed against the grip roller7and a state where the pinch roller8is kept a distance from the grip roller7. A motor rotates the cam, the motor and the cam not being shown. A third sensor50cis provided upstream of the pinch roller8in the second path30c.

The housing path30dincludes a fourth sensor50dat its end opposite to the switch guide20.

The ejection path30eincludes a paper ejection roller14that transports the recording paper2aand a pinch roller15that faces the paper ejection roller14. A paper ejection motor14arotates the paper ejection roller14. A cam, which is not shown, changes a position of the pinch roller15between a state where the pinch roller15is pressed against the paper ejection roller14and a state where the pinch roller15is kept a distance from the paper ejection roller14. A motor rotates the cam, the motor and the cam not being shown.

The ejection path30eincludes guide rollers29k,291,29mthat smoothly transport the recording paper2a. A fifth sensor50eis provided between the auxiliary guide21and the guide roller29kin the ejection path30e.

The paper feed motor9aand the transport motor7aare stepping motors and are driven by drive pulses sent from a motor controller60, which will be described below. The paper ejection motor14ais a DC motor and is driven by the motor controller60.

The motors (not shown) that rotate the cams to change the positions of the pinch rollers8,10,12, and15, the motor that rotates the recording paper roll2, the motor that rotates the ink sheet winding bobbin3, and the motor that rotates the ink sheet unwinding bobbin4for unwinding the ink sheet5are the DC motors and are driven by the motor controller60, which will be described below.

FIGS. 3A and 3Bare diagrams showing a configuration and operations of the switch guide20in the thermal printer100. InFIGS. 3A and 3B, a broken line illustrates the transport path of the recording paper2a.FIG. 3Ashows a state where the switch guide20connects the guide path30ato the first path30b, namely, the state where the switch guide20selects the first path30b. In the state where the switch guide20selects the first path30b, the second path30cis simultaneously connected to the housing path30d.

On the other hand,FIG. 3Bshows a state where the switch guide20connects the guide path30ato the second path30c, namely, the state where the switch guide20selects the second path30c.

As shown inFIGS. 3A and 3B, a switch guide motor20brotates a cam20cto change an angle of a lever20apressed against the cam20c. The lever20ais fixed to the switch guide20, so that a change in the angle of the lever20achanges the angle of the switch guide20to cause the state shown inFIG. 3AorFIG. 3B.

FIGS. 4A and 4Bare diagrams showing a configuration and operations of the auxiliary guide21in the thermal printer100. InFIGS. 4A and 4B, a broken line illustrates the transport path of the recording paper2a.FIG. 4Ashows a state where the auxiliary guide21supports the transport path such that the first path30bis smoothly connected to the other entrance of the gap between the thermal head1and the platen roller6. In other words, it is the state where the auxiliary guide21selects the first path30b.

On the other hand,FIG. 4Bshows a state where the auxiliary guide21supports the transport path such that the ejection path30eis smoothly connected to the other entrance of the gap between the thermal head1and the platen roller6. In other words, it is the state where the auxiliary guide21selects the ejection path30e.

As shown inFIGS. 4A and 4B, an auxiliary guide motor21brotates a cam21cto change an angle of a lever21apressed against the cam21c, causing a change in the angle of the auxiliary guide21. The lever21ais fixed to the auxiliary guide21, so that the change in the angle of the auxiliary guide21causes the state shown inFIG. 4AorFIG. 4B.

FIG. 5is a functional block diagram of the thermal printer100according to the preferred embodiment of the present invention. The thermal printer100includes a controller40that controls printing operations. The controller40receives detection signals for indicating the detection of the recording paper2afrom a first sensor50a, a second sensor50b, a third sensor50c, a fourth sensor50d, and a fifth sensor50e. The thermal printer100includes the motor controller60that controls each motor in the thermal printer100. The controller40controls the motor controller60in response to the detection signals sent from the first sensor50a, the second sensor50b, the third sensor50c, the fourth sensor50d, and the fifth sensor50e. The motor controller60outputs the drive pulses for driving each stepping motor in the thermal printer100. As shown inFIG. 5, the motor controller60sends the drive pulses to the paper feed motor9aand the transport motor7a. Moreover, the paper ejection motor14a, a platen roller motor6athat rotates the platen roller6, the switch guide motor20b, and the auxiliary guide motor21bare the DC motors and are driven by the motor controller60.

The motor controller60also drives the DC motors (not shown) that rotate the cams to change the positions of the pinch rollers8,10,12, and15. The motor controller60also drives the DC motors (not shown) that rotate the recording paper roll2, the ink sheet winding bobbin3, and the ink sheet unwinding bobbin4.

To suppress slack in the recording paper2aduring transport, torque limiters are provided between the paper feed motor9aand the paper feed rollers9,11and between the paper ejection motor14aand the paper ejection roller14.

The thermal printer100of the preferred embodiment has a first print function (operation mode) of switching the switch guide20to the first path30b(namely, causing the switch guide20to be in the state ofFIG. 3A) and guiding the recording paper2ainto the first path30bfor printing on the first main surface (namely, back side) of the recording paper2a.

The thermal printer100of the preferred embodiment further has a rewind function (operation mode) of rewinding the recording paper2aon which printing has been performed by the first print function (operation mode).

The thermal printer100of the preferred embodiment further has a second print function (operation mode) of switching the switch guide20to the second path30c(namely, causing the switch guide to be in the state ofFIG. 3B) after the recording paper2ahas been rewound by the rewind function (operation mode) and guiding the recording paper2ainto the second path30cfor printing on the second main surface (namely, front side) of the recording paper2a. Moreover, the thermal printer100of the preferred embodiment performs printing on both the first and second main surfaces of the recoding paper2abeing connected to the recording paper roll2.

FIG. 6is a flow chart showing printing operations of the thermal printer100. First, the thermal printer100performs printing on the first main surface of the recording paper2a(steps S101to S103inFIG. 6). This corresponds to the first print function (operation mode). Next, the thermal printer100rewinds the recording paper2a(step S104inFIG. 6). This corresponds to the rewind function (operation mode). Then, the thermal printer100performs printing on the second main surface of the recording paper2a(steps S105to S107inFIG. 6). This corresponds to the second print function (operation mode).

First, back-side printing operations will be described below with reference to the flow chart ofFIG. 6andFIGS. 7 to 10. As shown inFIG. 7, a tip of the recording paper2ais located at the position capable of being detected by the first sensor50ain the initial state. At this time, only the first sensor50aoutputs the detection signal indicating the detection of the recording paper2awhile the other sensors (second to fifth sensors50b,50c,50d,50e) do not output the detection signals. In this initial state, the motor controller60controls the drive of the switch guide motor20band causes the switch guide20to select the first path30b(step S101inFIG. 6). In other words, the switch guide20is caused to be in the state ofFIG. 3A. At the same time, the motor controller60causes the pinch roller10to be pressed against the paper feed roller9via the recording paper2a. The motor controller60simultaneously causes the pinch roller12to be pressed against the paper feed roller11. In addition, the motor controller60controls the drive of the auxiliary guide motor21band causes the auxiliary guide21to select the first path30b. In other words, the auxiliary guide21is caused to be in the state ofFIG. 4A.

Next, in the step S102inFIG. 6, the motor controller60controls the drive of the paper feed motor9ato rotate the paper feed roller9, and thus the recording paper2apasses through the switch guide20to be guided into the first path30b. The motor, which is not shown, rotates the recording paper roll2in the transport direction in synchronization with the rotation of the paper feed roller9. When the motor controller60outputs the predetermined number of drive pulses to the paper feed motor9a, the recording paper2areaches the portion between the paper feed roller11and the pinch roller12. The motor controller60continues to drive the paper feed motor9a. When the recording paper2areaches the second sensor50b, the second sensor50boutputs the detection signal to the controller40. When the controller40receives the detection signal from the second sensor50b, the motor controller60drives the transport motor7ato rotate the grip roller7. If the detection signal is not output from the second sensor50bdespite the fact that the motor controller60outputs the drive pulses for the recording paper2ato reach the second sensor50b, the controller40gives a warning about a paper jam, for example, to a user.

As the motor controller60continues to drive the paper feed motor9a, the recording paper2ais guided to the one entrance of the gap between the thermal head1and the platen roller6. As the motor controller60continues to drive the paper feed motor9a, the recording paper2apasses through the gap between the thermal head1and the platen roller6to reach the third sensor50c.FIG. 8shows this state. The motor controller60rotates the ink sheet winding bobbin3and the ink sheet unwinding bobbin4to transport the screen of yellow (Y) of the ink sheet5to a printing position.

In the state shown inFIG. 8, the third sensor50coutputs the detection signal. When receiving the detection signal from the third sensor50c, the controller40stops the paper feed motor9aand the transport motor7a. At the same time, the pinch roller8is pressed against the grip roller7via the recording paper2a. Then, the motor controller60controls the transport motor7ato rotate the grip roller7and transports the recording paper2ain the direction opposite to the direction from which the recording paper2ais transported. At this time, the motor controller60also rotates the paper feed roller9and the paper feed roller11in synchronization with the rotation of the grip roller7. When outputting the predetermined number of drive pulses to the transport motor7a, the motor controller60stops the transport motor7a. Then, the platen roller6is pressed against the thermal head1via the recording paper2aand the ink sheet5.FIG. 9shows this state.

Next, in the step S103inFIG. 6, printing on the first main surface (namely, back side) of the recording paper2ais started. In other words, in the state ofFIG. 9, the motor controller60transports the ink sheet5and also rotates the platen roller6and the grip roller7to transport the recording paper2a. After the ink sheet5and the recording paper2ahave been transported by the predetermined number of drive pulses, the thermal head1is heated to start printing yellow (Y). The recording paper2aon which yellow (Y) has been printed passes through the second path30cand is housed in the housing path30dvia the switch guide20. As the recording paper2ais transported by the predetermined number of drive pulses, the ink sheet5is pressed against the recoding paper2aand is transported, completing printing of yellow (Y).FIG. 10shows this state.

In the state ofFIG. 10, the fourth sensor50ddetects the recording paper2aand outputs the detection signal. If the detection signal is not output from the fourth sensor50ddespite the fact that the printing of yellow (Y) is completed, the controller40gives a warning about a paper jam, for example, to the user.

Next, the motor controller60releases the thermal head1from the pressure of the platen roller6and rotates the grip roller7to rewind the recording paper2ato the position shown inFIG. 8. At this time, the paper feed roller9, the paper feed roller11, and the recording paper roll2are also rotated in synchronization with the grip roller7. The motor controller60rotates the ink sheet winding bobbin3and the ink sheet unwinding bobbin4to transport the screen of magenta (M) of the ink sheet5to a printing position. Then, magenta (M) is printed in the same operation as the printing of yellow (Y). Hereinafter, the similar printing operation is repeated to print cyan (C) and over coat (OP). This completes the printing on the first main surface (namely, back side) of the recording paper2a.

Printing is performed on the second main surface (namely, front side) of the recording paper2a, followed by the printing on the first main surface (namely, back side) of the recording paper2a. Front-side printing operations will be described below with reference to the flow chart ofFIG. 6andFIGS. 11 to 13.

When the back-side printing operations are completed, the recording paper2ais in the state ofFIG. 10. The motor controller60releases the thermal head1from the pressure of the platen roller6and also releases the grip roller7from the pressure of the pinch roller8. Then, the motor controller60rotates the recording paper roll2in the direction to which the recording paper2ais rewound. The paper feed roller9and the paper feed roller11are rotated in synchronization with the rotation of the recording paper roll2. As the recording paper2apasses through the first sensor50a, the detection signal output from the first sensor50ais changed from present to absent. When the output of the first sensor50ais changed, the motor controller60outputs the predetermined number of drive pulses and subsequently stops to transport the recording paper2a. In the operations as described above, the recording paper2ais rewound to the portion upstream of the switch guide20(step S104inFIG. 6).

Next, in the step S105inFIG. 6, the motor controller60controls the drive of the switch guide motor20band causes the switch guide20to select the second path30c. In other words, the switch guide20is caused to be in the state ofFIG. 3B. At the same time, the motor controller60controls the drive of the auxiliary guide motor20band causes the auxiliary guide21to select the ejection path30e. In other words, the auxiliary guide21is caused to be in the state ofFIG. 4B. The motor controller60causes the pinch roller10to be pressed against the paper feed roller9via the recording paper2a.FIG. 11shows this state.

Next, in the step S106inFIG. 6, the motor controller60controls the drive of the paper feed motor9ato rotate the paper feed roller9, and thus the recording paper2apasses through the switch guide20to be guided into the second path30c. When the recording paper2areaches the third sensor50c, the third sensor50coutputs the detection signal. When the controller40receives the detection signal from the third sensor50c, the motor controller60further transports the recording paper2aby the predetermined number of drive pulses. The motor controller60causes the pinch roller8to be pressed against the grip roller7via the recording paper2a.FIG. 12shows this state.

Furthermore, the motor controller60transports the recording paper2a, and as the recording paper2areaches the fifth sensor50e, the fifth sensor50eoutputs the detection signal. When the controller40receives the detection signal from the fifth sensor50e, the motor controller60further transports the recording paper2aby the predetermined number of drive pulses. Thus, the recording paper2ais transported to a printing start position. The motor controller60rotates the ink sheet winding bobbin3and the ink sheet unwinding bobbin4to transport the screen of yellow (Y) of the ink sheet5to the printing position. The motor controller60causes the platen roller6to be pressed against the thermal head1via the recording paper2aand the ink sheet5.FIG. 13shows this state. The recording paper2athat has been transported to the printing start position does not reach the ejection opening16.

Next, in the step S107inFIG. 6, printing on the second main surface (namely, front side) of the recording paper2ais started. In other words, in the state ofFIG. 13, the motor controller60transports the ink sheet5and also rotates the platen roller6and the grip roller7to transport the recording paper2ain the rewind direction while the thermal head1is heated to print yellow (Y). The recording paper2aand the ink sheet5are transported by the predetermined number of drive pulses, completing printing of yellow (Y).

Next, the motor controller60releases the thermal head1from the pressure of the platen roller6and rotates the grip roller7to transport the recording paper2ato the position shown inFIG. 13. At this time, the paper feed roller9, the paper feed roller11, and the recording paper roll2are also rotated in synchronization with the grip roller7. The motor controller60rotates the ink sheet winding bobbin3and the ink sheet unwinding bobbin4to transport the screen of magenta (M) of the ink sheet5to the printing position. Then, magenta (M) is printed in the same operation as the printing of yellow (Y). Hereinafter, the similar printing operation is repeated to print cyan (C) and over coat (OP). This completes the printing on the second main surface (namely, back side) of the recording paper2a.

After the completion of the printing on the second main surface (namely, front side) of the recording paper2a, the motor controller60rotates the grip roller7, the paper feed roller9, and the recording paper roll2to transport the recording paper2ato the ejection opening16while the motor controller60causes the pinch roller8to be pressed against the grip roller7. When the recording paper2areaches the fifth sensor50e, the fifth sensor50eoutputs the detection signal. The detection signal from the fifth sensor50eis used to monitor a paper jam. The motor controller60causes the pinch roller15to be pressed against the paper ejection roller14via the recording paper2a, rotates the paper ejection roller14, the grip roller7, the paper feed roller9, and the recording paper roll2, and further transports the recording paper2aby the predetermined number of drive pulses. As a result, a portion of the recording paper2aon which printing has been performed is exposed to the outside of the case of the thermal printer100from the ejection opening16. Then, the recording paper2ais cut with the cutter16aprovided at the ejection opening16, and the printed matter is ejected from the ejection opening16(step S108inFIG. 6).

The thermal printer100of the preferred embodiment includes: the thermal head1; the platen roller6disposed to face the thermal head1; the first path30bthat guides the recording paper2adrawn from the recording paper roll2to the one entrance of the gap between the thermal head1and the platen roller6such that the first main surface of the recording paper2ais on the thermal head1side; the second path30cthat guides the recording paper2adrawn from the recording paper roll2to the other entrance of the gap between the thermal head1and the platen roller6such that the second main surface of the recording paper2ais on the thermal head1side; and the switch guide20that switches between the first path30band the second path30c.

Therefore, the thermal printer100of the preferred embodiment can perform double-sided printing in the simple configuration since the two paths, namely, the first path30band the second path30care provided and can be switched therebetween by the switch guide20, the first path30band the second path30crespectively guiding the first main surface and the second main surface of the recording paper2adrawn from the recording paper roll2to the gap between the thermal head1and the platen roller6. The thermal printer100of the preferred embodiment can perform printing on both the sides without the mechanism for reversing the recording paper roll2, achieving double-sided printing in the more simple configuration than the conventional configuration. The thermal printer100has the more simple configuration than the conventional configuration, allowing for the miniaturization thereof. Moreover, the thermal printer100does not include the complex mechanism for reversing the recording paper roll2, allowing for a reduced manufacturing cost.

After printing on the first main surface has been performed, the thermal printer100of the preferred embodiment rewinds the recording paper2aaround the recording paper roll2to subsequently perform printing on the second main surface, eliminating the need to cut the recording paper2aduring printing. This can reduce the number of rollers for transporting the recording paper2acompared to the case where the recording paper2ais cut during printing. In other words, the number of components is reduced compared to the conventional configuration, achieving the simplified configuration of the thermal printer100. The number of components is reduced compared to the conventional configuration, achieving the miniaturization of the thermal printer100.

The thermal printer100of the preferred embodiment further includes: the first print function of switching the switch guide20to the first path30band guiding the recording paper2ainto the first path30bto perform printing on the first main surface of the recording paper2a; the rewind function of rewinding the recording paper2aon which printing has been performed by the first print function; and the second print function of switching the switch guide20to the second path30cafter the recording paper2ahas been rewound by the rewind function and guiding the recording paper2ainto the second path30cto perform printing on the second main surface of the recording paper2a. The thermal printer100performs printing on both the first and second main surfaces of the recording paper2abeing connected to the recording paper roll2.

Therefore, the thermal printer100of the preferred embodiment has the first print function, whereby printing can be performed on the first main surface of the recording paper2ausing the first path30b. The thermal printer100has the rewind function, whereby the recording paper2ahaving the first main surface on which printing has been performed can be rewound around the recording paper roll2. The thermal printer100has the second print function, whereby printing can be performed on the second main surface of the recording paper2ausing the second path30c.

The thermal printer100of the preferred embodiment performs printing on both the first and the second main surfaces of the recording paper2abeing connected to the recording paper roll2. This can reduce the number of rollers for transporting and rewinding the recording paper2acompared to the case where printing is performed on the first and second main surfaces of the recording paper2athat has been cut from the recording paper roll2. The reduction in the number of components can lead to the miniaturization of the thermal printer100and the reduced manufacturing cost.

The thermal printer100further includes the housing path30dthat houses the recording paper2aon which printing has been performed by the first print function. The housing path30dis curved in the same direction as a winding direction of the recording paper roll2.

Therefore, the housing path30dthat houses the recording paper2aon which printing has been performed by the first print function can prevent a stain and dust from adhering to the recording paper2acompared to the case where the housing path30dis not provided and the recording paper2ais exposed to the outside of the case. Furthermore, the recording paper2ais curled in the winding direction thereof, and thus the housing path30dis provided to be bent in the same direction as the winding direction of the recording paper2a. This can suppress a paper jam when the recording paper2ais guided into the housing path30d.

The thermal printer100further includes the ejection path30ethat guides the recording paper2ato the ejection opening16, the recording paper2ahaving passed through the second path30c. The ejection opening16is provided with the cutter16athat cuts the recording paper2a. The ejection path30ehas a distance greater than the effective print length in the unit screen of the ink sheet5used in the thermal printer100.

Therefore, the ejection path30ehas a distance greater than the effective print length in the unit screen of the ink sheet5, whereby the tip of the recording paper2adoes not reach the ejection opening16upon printing on the second main surface of the recording paper2a. Thus, the first main surface (namely, back side) of the recording paper2acan be prevented from damage caused by the cutter16aat the ejection opening16. Since the thermal printer100of the preferred embodiment performs double-sided printing, printing is also performed on the surface (namely, the first main surface) of the recording paper2aon the side provided with the cutter16a. Therefore, it is particularly effective to prevent the first main surface of the recording paper2afrom damage caused by the cutter16a.

In addition, according to the present invention, the above preferred embodiments can be appropriately varied or omitted within the scope of the invention.