JP6366402B2 - Thermal printer - Google Patents

Description

  The present invention relates to a thermal printer, and more particularly, to a thermal printer that performs double-sided printing that includes a mechanism for correcting curling of recording paper wound in a roll.

  2. Description of the Related Art In thermal printers that perform printing by thermally transferring to recording paper, a recording paper roll in which recording paper is wound in a roll shape is widely used because of its cost advantage. This recording paper roll is obtained by winding a long recording paper into a cylindrical shape around, for example, a paper tube serving as a winding core. Each time printing is performed, a necessary amount of recording paper is unwound from the recording paper roll, and after the printing is completed, the recording paper is cut from the recording paper roll by a predetermined length and discharged.

  The recording paper unwound from the recording paper roll has a curl (hereinafter referred to as curl). The curl becomes more prominent as the recording paper is closer to the winding core.

  Therefore, if the unwound recording paper is ejected with curling, the printed material cannot be stacked due to the curl, the quality of the printed material is impaired, or paper jams may occur. It was.

  In a conventional thermal printer, a curl correction mechanism is arranged that corrects curl by bending a recording sheet in a direction opposite to the curl direction. For example, in Patent Document 1, the curl correction mechanism is disposed downstream of the thermal head with respect to the feeding direction in which the recording paper is printed, and at a position where the residual heat from the thermal head remains on the recording paper. .

JP 2007-197123 A

  In a conventional thermal printer, the recording paper and the ink ribbon are pressed against the ink ribbon peeling member that peels the recording paper and the ink ribbon after passing through the thermal head. ing. However, since the ink ribbon peeling member cannot be configured to separate only the ink ribbon from the recording paper, there has been a problem that the ink ribbon peels off.

  At the time of printing, the recording paper is precisely conveyed at a predetermined constant speed so that the change in the conveyance speed of the recording paper does not affect the printing. However, the conventional curl correction method has a problem that the speed at which the recording paper passes through the thermal head fluctuates, so that the print becomes non-uniform and the print quality is deteriorated.

  Further, in a thermal printer capable of double-sided printing, there is a problem that a curl correction mechanism that is effective for correcting the roll winding direction has an adverse effect when the opposite surface is used.

  The present invention has been made to solve the above-described problems, and is a thermal printer capable of correcting curling of recording paper, having good print quality, high reliability, and capable of duplex printing. For the purpose of provision.

A thermal printer according to the present invention includes a thermal head, a platen roller disposed opposite to the thermal head, and a recording paper drawn from a recording paper roll so that the first main surface of the recording paper comes to the thermal head side. A first path that leads to one entrance of the gap between the head and the platen roller, and a recording paper drawn from the recording paper roll, the thermal head and the platen roller so that the second main surface of the recording paper is on the thermal head side. A second path that leads to the other inlet of the gap, a switching guide that switches between the first and second paths, and a curl correction mechanism that corrects the curl of the recording paper. Among the two paths, the inner surface printing path through which the recording paper is guided when printing on the inner surface of the recording paper roll is disposed upstream of the platen roller. Allow Der switching whether to correct the curl of Rokushi is, the curl correcting mechanism includes a curl correcting roller arranged platen roller and opposite sides of the recording sheet, the conveyance path of the recording paper the position of the curl straightening roller And a correction roller position moving mechanism that moves in a direction that interferes with the curl correction roller, the curl correction roller moves, the curl correction roller interferes with the recording paper, and the recording paper moves according to the interference accompanying the movement of the curl correction roller. The curl correction mechanism further includes an auxiliary roller, and the curl correction roller and the auxiliary roller are held by the same holding member, and the correction roller position moving mechanism moves the holding member to move the auxiliary roller. The position of the auxiliary roller also moves, and the auxiliary roller moves to the first position. When the auxiliary roller moves to the second position, the auxiliary roller moves the recording paper from the inlet of the gap between the thermal head and the platen roller. assisting in directing the path for discharging the recording sheet.

  In the thermal printer according to the present invention, the curl correction mechanism is arranged not on the downstream side of the thermal head but on the upstream side in the inner surface printing path (that is, the first path). Not placed in between. Therefore, the curl correction mechanism does not hinder the peeling of the ink sheet. In addition, the recording paper conveyance speed can be kept constant. Further, the curl correction mechanism can be freely switched on and off in conjunction with the printing operation. Therefore, it is possible to obtain a thermal printer with good print quality and high reliability.

It is sectional drawing of the thermal printer which concerns on embodiment of this invention. FIG. 2 is a diagram illustrating a recording paper conveyance path in FIG. 1. It is a figure which shows the structure and operation | movement of a switching guide with which the thermal printer which concerns on embodiment of this invention is equipped. It is a figure which shows the structure and operation | movement of the curl correction mechanism with which the thermal printer which concerns on embodiment of this invention is equipped. It is a figure which shows the structure and operation | movement of the curl correction mechanism with which the thermal printer which concerns on embodiment of this invention is equipped. It is a figure which shows the structure and operation | movement of the curl correction mechanism with which the thermal printer which concerns on embodiment of this invention is equipped. It is a functional block diagram of the thermal printer which concerns on embodiment of this invention. It is a flowchart which shows the printing operation of the thermal printer which concerns on embodiment of this invention. It is a figure explaining the back surface printing operation | movement of the thermal printer which concerns on embodiment of this invention. It is a figure explaining the back surface printing operation | movement of the thermal printer which concerns on embodiment of this invention. It is a figure explaining the back surface printing operation | movement of the thermal printer which concerns on embodiment of this invention. It is a figure explaining the back surface printing operation | movement of the thermal printer which concerns on embodiment of this invention. It is a figure explaining the surface printing operation | movement of the thermal printer which concerns on embodiment of this invention. It is a figure explaining the surface printing operation | movement of the thermal printer which concerns on embodiment of this invention. It is a figure explaining the surface printing operation | movement of the thermal printer which concerns on embodiment of this invention. It is a flowchart which shows operation | movement of the curl correction mechanism of the thermal printer which concerns on embodiment of this invention. It is a figure which shows the relationship between the curl amount with respect to the winding diameter of a recording paper roll, and the curl correction amount. FIG. 4 is a diagram illustrating timings of a recording sheet conveyance direction, a thermal head heater on / off, and a holding member rotation of the thermal printer according to the embodiment of the present invention.

<Embodiment 1>
<Overall configuration>
FIG. 1 is a diagram showing a configuration of a thermal printer 100 according to an embodiment of the present invention. FIG. 2 is a diagram showing a recording paper conveyance path of the thermal printer 100 in FIG. As shown in FIG. 1, the thermal printer 100 includes a thermal head 1 and a platen roller 6 disposed to face the thermal head 1. The thermal printer 100 includes an ink sheet winding bobbin 3 that winds up the ink sheet 5 and an ink sheet winding bobbin 4 that winds out the ink sheet 5. In addition, the recording paper roll 2 in which the recording paper 2 a is wound in a roll shape is set in the thermal printer 100.

  The thermal head 1 performs thermal transfer by heating the ink sheet 5 while partially pressing the ink sheet 5 against the recording paper 2 a on the platen roller 6. As shown in FIG. 4, the thermal head 1 includes a main body, a heater 30, an IC (Integrate Circuit) cover 13, a heat sink (not shown), and a peeling roller 31. The heater 30 is a heat generating part of the thermal head 1. The IC cover 13 covers the IC portion of the thermal head 1. The heat sink cools the thermal head 1. The peeling roller 31 has a cylindrical surface in contact with a portion of the ink sheet 5 located between the thermal head 1 and the take-up bobbin 8, is rotatably supported, and peels the ink sheet 5 from the recording paper 2a. It is. The guide roller 32 has a cylindrical surface that is in contact with a portion of the ink sheet 5 located between the peeling roller 31 and the take-up bobbin 8. It is a guide to people.

  As shown in FIG. 2, the thermal printer 100 includes an introduction path 30 a that guides the recording paper 2 a drawn from the recording paper roll 2 to the switching guide 20. The thermal printer also includes a first path 30b that leads to one entrance of a gap between the thermal head 1 and the platen roller 6 so that the first main surface (that is, the back surface) of the recording paper 2a is on the thermal head 1 side. . Further, the thermal printer 100 is configured such that the recording paper 2a pulled out from the recording paper roll 2 has a thermal head 1 and a platen roller 6 so that the second main surface (that is, the front surface) of the recording paper 2a is on the thermal head 1 side. A second path 30c leading to the other entrance of the gap.

  The thermal printer 100 further includes a switching guide 20 that switches between the first path 30b and the second path 30c. The switching guide 20 will be described later.

  The thermal printer 100 further includes a curl correction mechanism 40 that corrects curl (hereinafter referred to as curl) of the recording paper 2a and assists the conveyance path of the recording paper 2a. The curl correction mechanism 40 will be described later.

  The thermal printer 100 further includes a storage path 30d for storing the printed recording paper 2a guided to one entrance of the gap between the thermal head 1 and the platen roller 6 from the first path 30b. The storage path 30d is curved in the same direction as the winding direction of the recording paper roll 2.

  The thermal printer 100 further includes a discharge path 30e that guides the recording paper 2a that has passed through the second path 30c to the discharge port 16. The discharge port 16 is provided with a cutter 16a for cutting the recording paper 2a. In the present embodiment, the distance of the discharge path 30 e is larger than the effective print length on the unit screen of the ink sheet 5 used in the thermal printer 100. Here, the distance of the discharge path 30 e is the distance of the transport path from the gap between the thermal head 1 and the platen roller 6 to the discharge port 16.

  The ink sheet 5 has a yellow (Y) area for the unit screen, a magenta (M) area for the unit screen, a cyan (C) area for the unit screen, and an overcoat (OP) area for the unit screen. These groups are arranged as a set, and this set is repeatedly arranged. In each unit screen, margins (for example, 10 mm) that are not used for printing are provided at both ends of the ink sheet 5 in the longitudinal direction. An area excluding the margin from each unit screen is an effective print area used for printing. In each unit screen, the length in the longitudinal direction of the ink sheet 5 in the effective print area is referred to as an effective print length.

  In the introduction path 30 a, a paper feed roller 9 for conveying the recording paper 2 a and a pinch roller 10 facing the paper feed roller 9 are provided. The paper feed roller 9 is driven by a paper feed motor 9a. Further, the position of the pinch roller 10 is changed to a state in which the pinch roller 10 is pressure-bonded to the paper feed roller 9 or a state away from the paper feed roller 9 by a cam (not shown). This cam (not shown) is rotated by a motor (not shown).

  Guide rollers 29a, 29b, 29c, 29d, 29e, 29f, and 29g are provided in the introduction path 30a to smoothly convey the recording paper 2a. Further, a first sensor 50a is provided in front of the switching guide 20 in the introduction path 30a.

  In addition, dust removal rollers 13a and 13b are provided in the introduction path 30a. The dust removal rollers 13a and 13b are, for example, silicon rollers, and remove dust and the like adhering to the recording paper 2a.

  In the first path 30b, a paper feed roller 11 for transporting the recording paper 2a and a pinch roller 12 facing the paper feed roller 11 are provided. The paper feed roller 11 is rotated by a paper feed motor 9 a that is common to the paper feed roller 9. Further, the position of the pinch roller 12 is changed to a state in which the pinch roller 12 is pressure-bonded to the paper feed roller 11 or away from the paper feed roller 11 by a cam (not shown). This cam (not shown) is rotated by a motor (not shown).

  In the first path 30b, guide rollers 29h, 29i, 29j, and 29n are provided to smoothly convey the recording paper 2a. In the first path 30b, for example, a second sensor 50b is provided in the path between the guide roller 29i and the guide roller 29j.

  A grip roller 7 for conveying the recording paper 2a and a pinch roller 8 facing the grip roller 7 are provided in the second path 30c. The grip roller 7 is rotated by a transport motor 7a. Further, the position of the pinch roller 8 is changed to a state in which it is pressure-bonded to the grip roller 7 or a state away from the grip roller 7 by a cam (not shown). This cam (not shown) is rotated by a motor (not shown). A third sensor 50c is provided in front of the pinch roller 8 in the second path 30c.

  A fourth sensor 50d is provided at the end of the storage path 30d opposite to the switching guide 20.

  In the discharge path 30e, a paper discharge roller 14 for conveying the recording paper 2a and a pinch roller 15 facing the paper discharge roller 14 are provided. The paper discharge roller 14 is rotated by a paper discharge motor 14a. Further, the position of the pinch roller 15 is changed to a state in which it is pressed against the paper discharge roller 14 or a state away from the paper discharge roller 14 by a cam (not shown). This cam (not shown) is rotated by a motor (not shown).

  Guide rollers 29k, 29l, and 29m are provided in the discharge path 30e to smoothly convey the recording paper 2a. In the discharge path 30e, a fifth sensor 50e is provided in the path between the auxiliary guide 21 and the guide roller 29k.

  The paper feed motor 9a and the transport motor 7a are stepping motors and are driven by drive pulses sent from a motor control unit 60 described later. The paper discharge motor 14 a is a DC motor and is driven by the motor control unit 60.

  Further, a motor (not shown) that rotates a cam for changing the postures of the pinch rollers 10, 12, 8, and 15, a motor that rotates the recording paper roll 2, a motor that rotates the ink sheet winding bobbin 3, and ink A motor for rotating the ink sheet unwinding bobbin 4 for unwinding the sheet 5 is a DC motor, and is driven by a motor control unit 60 described later.

<Switching guide>
FIGS. 3A and 3B are diagrams showing the configuration and operation of the switching guide 20 provided in the thermal printer 100. FIG. 3 (a) and 3 (b), the broken line indicates the conveyance path of the recording paper 2a. FIG. 3A shows a state where the switching guide 20 connects the introduction route 30a and the first route 30b, that is, a state where the switching guide 20 selects the first route 30b. In the state where the switching guide 20 selects the first path 30b, the second path 30c and the storage path 30d are simultaneously connected.

  On the other hand, FIG. 3B shows a state where the switching guide 20 connects the introduction path 30a and the second path 30c, that is, a state where the switching guide 20 selects the second path 30c.

  As shown in FIGS. 3A and 3B, when the cam 20c is rotated by the switching guide motor 20b, the angle of the lever 20a pressed against the cam 20c changes. Since the lever 20a is fixed to the switching guide 20, when the angle of the lever 20a changes, the angle of the switching guide 20 changes, and the state shown in FIG. 3A or 3B is obtained.

<Curl correction mechanism>
4, 5, and 6 are diagrams illustrating the configuration and operation of the curl correction mechanism 40 provided in the thermal printer 100. The curl correction mechanism 40 includes a curl correction roller 41, an auxiliary roller 42, a rotation shaft 45, a holding member 43, and a DC motor 44. The holding member 43 holds the curl correction roller 41 and the auxiliary roller 42. The holding member 43 rotates about the rotation shaft 45. The DC motor 44 is power for rotating the holding member 43 via a connection drive unit (not shown). When the holding member 43 is rotated about the rotation shaft 45 by the DC motor 44, the positions of the curl correction roller 41 and the auxiliary roller 42 are moved.

  FIG. 4 shows a state in which the auxiliary roller 42 assists the conveyance path so that the first path 30b and the other entrance of the gap between the thermal head 1 and the platen roller 6 are smoothly connected. That is, the auxiliary roller 42 has moved to the first position and selected the first path 30b. FIG. 4 shows a state where curl correction is not performed (hereinafter referred to as an off state). In the off state, the holding member 43 rotates in a direction away from the platen roller 6, whereby the position of the auxiliary roller 42 moves and is pressed against the recording paper 2 a. As a result, the recording paper 2 a does not follow the roller surface of the platen roller 6.

  FIG. 5 shows a state in which the curl correction mechanism 40 is performing curl correction of the recording paper 2a (hereinafter referred to as an “on state”). As shown in FIG. 5, in the ON state, the holding member 43 rotates in a direction approaching the platen roller 6, so that the curl correction roller 41 moves in a direction that interferes with the conveyance path of the recording paper 2a. The recording paper 2 a follows the roller surface of the platen roller 6 due to the interference of the curl correction roller 41.

  Further, in FIG. 6, the auxiliary roller 42 of the curl correction mechanism 40 assists the conveyance path so that the discharge path 30 e and the other entrance of the gap between the thermal head 1 and the platen roller 6 are smoothly connected. State. That is, the auxiliary roller 42 has moved to the second position and selected the discharge path 30e.

  As shown in FIGS. 4, 5, and 6, the curl correction roller 41 and the auxiliary roller 42 are moved along with the rotation of the holding member 43, so that the curl correction is turned on and off and the auxiliary roller 42 is selected. The first path 30b and the discharge path 30e are switched.

  4 to 6, the platen roller 6 extends in a direction perpendicular to the paper surface. For example, the holding member 43 of the curl correction mechanism 40 is disposed behind the end of the platen roller 6 on the back side of the paper surface, so that the holding member 43 does not interfere with the platen roller 6.

<Functional block diagram>
FIG. 7 is a functional block diagram of the thermal printer 100 according to the embodiment of the present invention. The thermal printer 100 includes a thermal printer control unit 80 that controls a printing operation. The thermal printer controller 80 receives detection signals indicating that the recording paper 2a has been detected from the first to fifth sensors 50a, 50b, 50c, 50d, and 50e. The thermal printer 100 also includes a motor control unit 60 that controls each motor provided in the thermal printer 100. The thermal printer control unit 80 controls the motor control unit 60 according to detection signals transmitted from the first to fifth sensors 50a, 50b, 50c, 50d, and 50e. The motor control unit 60 outputs drive pulses for driving each stepping motor provided in the thermal printer 100. As shown in FIG. 5, the motor control unit 60 sends drive pulses to the paper feed motor 9a and the transport motor 7a. The paper discharge motor 14 a, the platen roller motor 6 a that rotates the platen roller 6, the switching guide motor 20 b, and the curl correction motor 21 b are DC motors and are driven by the motor control unit 60.

  The motor control unit 60 also drives a DC motor (not shown) that rotates a cam for changing the positions of the pinch rollers 10, 12, 8, and 15. The motor control unit 60 also drives a DC motor (not shown) that rotates the recording paper roll 2, the ink sheet winding bobbin 3, and the ink sheet winding bobbin 4.

  As shown in FIG. 7, the curl correction mechanism 40 of the thermal printer 100 includes a winding diameter detection unit 72, a curl amount estimation unit 46, and a curl correction mechanism control unit 47. The winding diameter detection unit 72 detects the winding diameter of the recording paper roll 2. The curl amount estimation unit 46 estimates the curl amount of the recording paper 2 a from the winding diameter of the recording paper roll 2. The curl correction mechanism control unit 47 calculates the rotation amount of the holding member 43 based on the curl amount estimated by the curl amount estimation unit 46. Then, the motor control unit 60 is controlled in conjunction with the printing operation controlled by the thermal printer control unit 80. The motor control unit 60 rotates the holding member 43 by driving the curl correction motor 44 based on a control instruction including the rotation amount of the holding member 43 sent from the curl correction mechanism control unit 47.

  Further, in order to suppress the slack of the recording paper 2a being conveyed, there is a torque between the paper feed motor 9a and the paper feed rollers 9, 11, and between the paper discharge motor 14a and the paper discharge roller 14. A limiter is provided.

<Operation>
In the thermal printer 100 according to the present embodiment, the switching guide 20 is switched to the first path 30b (that is, the switching guide 20 is in the state shown in FIG. 3A), and the recording paper 2a is transferred to the first path 30b. A first printing function is provided for printing on the first main surface (that is, the back surface) of the recording paper 2a.

  The thermal printer 100 according to the present embodiment further includes a rewind function for rewinding the recording paper 2a after printing by the first print function.

  The thermal printer 100 according to the present embodiment further switches the switching guide 20 to the second path 30c after rewinding by the rewinding function (that is, the switching guide 20 is in the state shown in FIG. 3B). The recording paper 2a is introduced into the second path 30c, and a second printing function for performing printing on the second main surface (ie, the front surface) of the recording paper 2a is provided. Further, the thermal printer 100 according to the present embodiment performs printing on both the first and second main surfaces of the recording paper 2a in a state where the recording paper 2a is connected to the recording paper roll 2.

  FIG. 8 is a flowchart showing the printing operation of the thermal printer 100. First, the thermal printer 100 performs printing on the first main surface of the recording paper 2a (steps S101 to S103 in FIG. 8). This corresponds to the first printing function. Next, the thermal printer 100 rewinds the recording paper 2a (step S104 in FIG. 8). This corresponds to the rewind function. Then, the thermal printer 100 performs printing on the second main surface of the recording paper 2a (steps S105 to S107 in FIG. 8). This corresponds to the second printing function.

<Back side printing operation>
First, the back surface printing operation will be described with reference to the flowchart of FIG. 8 and FIGS. 9 to 12. As shown in FIG. 9, the leading edge of the recording paper 2a is in a position detected by the first sensor 50a as an initial state. At this time, only the first sensor 50a outputs a detection signal indicating that the recording paper 2a has been detected, and the other sensors (second to fifth sensors 50b, 50c, 50d, 50e) output detection signals. Not. In this initial state, the motor control unit 60 controls the drive of the switching guide motor 20b to cause the switching guide 20 to select the first path 30b (step S101 in FIG. 8). That is, the switching guide 20 is in the state shown in FIG. At the same time, the motor control unit 60 presses the pinch roller 10 against the paper feed roller 9 via the recording paper 2a. At the same time, the motor control unit 60 presses the pinch roller 12 against the paper feed roller 11. Further, the motor control unit 60 controls the drive of the curl correction motor 84 to cause the auxiliary roller 82 to select the first path 30b. That is, as the holding member 43 rotates, the auxiliary roller 82 moves to the first position (position shown in FIG. 4).

  Next, in step S102 in FIG. 8, the motor control unit 60 controls the drive of the paper feed motor 9a to rotate the paper feed roller 9, so that the recording paper 2a passes through the switching guide 20, 1 path 30b. In synchronization with the rotation of the paper feed roller 9, the recording paper roll 2 is also rotated in the transport direction by a motor (not shown). When the motor control unit 60 outputs a predetermined number of drive pulses to the paper feed motor 9 a, the recording paper 2 a reaches between the paper feed roller 11 and the pinch roller 12. The motor control unit 60 continues to drive the paper feeding motor 9a. When the recording paper 2a reaches the second sensor 50b, the second sensor 50b outputs a detection signal to the thermal printer control unit 80. When the thermal printer control unit 80 receives the detection signal from the second sensor 50b, the motor control unit 60 drives the transport motor 7a to rotate the grip roller 7. In the case where the motor control unit 60 outputs a drive pulse for the recording paper 2a to reach the second sensor 50b but no detection signal is output from the second sensor 50b, the thermal printer control unit 80 For example, a warning indicating a paper jam or the like is issued to the user.

  The motor control unit 60 continues to drive the paper feeding motor 9 a, and the recording paper 2 a is guided to one entrance of the gap between the thermal head 1 and the platen roller 6. The motor controller 60 continues to drive the paper feed motor 9a, and the recording paper 2a passes through the gap between the thermal head 1 and the platen roller 6 and reaches the third sensor 50c. This state is shown in FIG. Further, the motor control unit 60 rotates the ink sheet winding bobbin 3 and the ink sheet winding bobbin 4 to convey the yellow (Y) screen of the ink sheet 5 to the printing position.

  In the state shown in FIG. 10, the third sensor 50c outputs a detection signal. When receiving the detection signal from the third sensor 50c, the thermal printer control unit 80 stops the paper feeding motor 9a and the conveying motor 7a. At the same time, the pinch roller 8 is pressed against the grip roller 7 via the recording paper 2a. Then, the motor control unit 60 controls the transport motor 7a to rotate the grip roller 7 and transport the recording paper 2a in the direction opposite to the transported direction. At this time, the motor control unit 60 also rotates the paper feed rollers 9 and 11 in synchronization with the rotation of the grip roller 7. The motor control unit 60 stops the transport motor 7a when a predetermined number of drive pulses are output to the transport motor 7a. Then, the platen roller 6 is pressed against the thermal head 1 via the recording paper 2 a and the ink sheet 5. This state is shown in FIG.

  Next, in step S103 in FIG. 8, printing is started on the first main surface (that is, the back surface) of the recording paper 2a. That is, in the state shown in FIG. 11, the motor control unit 60 conveys the recording sheet 2a by rotating the platen roller 6 and the grip roller 7 while conveying the ink sheet 5. When the predetermined number of drive pulses have been conveyed, the thermal head 1 is heated to start yellow (Y) printing. Note that the curl correction mechanism 80 corrects the curl of the recording paper 2a when printing is performed on the first main surface (that is, the back surface) of the recording paper 2a. The operation of the curl correction mechanism 40 will be described later. The recording paper 2 a printed with yellow (Y) passes through the second path 30 c and is stored in the storage path 30 d via the switching guide 20. The recording paper 2a is transported by a predetermined number of drive pulses, and the ink sheet 5 is transported in a pressure-bonded manner with the recording paper 2a, thereby completing yellow (Y) printing. This state is shown in FIG.

  In the state of FIG. 12, the fourth sensor 50d detects the recording paper 2a and outputs a detection signal. If the detection signal is not output from the fourth sensor 50d even when the yellow (Y) printing is completed, the thermal printer control unit 80 issues a warning indicating, for example, a paper jam to the user.

  Next, the motor control unit 60 releases the pressure bonding between the platen roller 6 and the thermal head 1, rotates the grip roller 7, and rewinds the recording paper 2a to the position shown in FIG. At this time, the paper feed rollers 9 and 11 and the recording paper roll 2 are also rotated in synchronization with the grip roller 7. Further, the motor control unit 60 rotates the ink sheet winding bobbin 3 and the ink sheet winding bobbin 4 to convey the magenta (M) screen of the ink sheet 5 to the printing position. Then, the magenta (M) printing is performed by the same operation as the yellow (Y) printing. Thereafter, the same printing operation is repeated to print cyan (C) and overcoat (OP). Thus, printing on the first main surface (that is, the back surface) of the recording paper 2a is completed.

<Surface printing operation>
Subsequent to printing on the first main surface (that is, the back surface) of the recording paper 2a, printing is performed on the second main surface (that is, the front surface) of the recording paper 2a. The front surface printing operation will be described with reference to the flowchart of FIG. 8 and FIGS. 13 to 15.

  When the back side printing operation is completed, the recording paper 2a is in the state shown in FIG. The motor control unit 60 releases the pressure bonding between the platen roller 6 and the thermal head 1 and also releases the pressure bonding between the pinch roller 8 and the grip roller 7. Then, the motor control unit 60 rotates the recording paper roll 2 in the direction of winding the recording paper 2a. Further, the paper feed rollers 9 and 11 are also rotated in synchronization with the rotation of the recording paper roll 2. When the recording paper 2a passes through the first sensor 50a, the output of the first sensor 50a changes from the presence of the detection signal to the absence of the detection signal. When the output of the first sensor 50a changes, the motor control unit 60 outputs a predetermined number of drive pulses and then stops the conveyance of the recording paper 2a. With the above operation, the recording paper 2a is rewound to the front of the switching guide 20 (step S104 in FIG. 8).

  Next, in step S105 of FIG. 8, the motor control unit 60 controls the drive of the switching guide motor 20b to cause the switching guide 20 to select the second path 30c. That is, the switching guide 20 is in the state shown in FIG. At the same time, the motor control unit 60 controls the driving of the curl correction motor 84 to cause the auxiliary roller 82 to select the discharge path 30e. That is, as the holding member 43 rotates, the auxiliary roller 82 moves to the second position (position shown in FIG. 6). Further, the motor control unit 60 presses the pinch roller 10 against the paper feed roller 9 via the recording paper 2a. This state is shown in FIG.

  Next, in step S106 in FIG. 8, the motor control unit 60 controls the drive of the paper feed motor 9a to rotate the paper feed roller 9, so that the recording paper 2a passes through the switching guide 20, 2 path 30c. When the recording paper 2a reaches the third sensor 50c, the third sensor 50c outputs a detection signal. When the thermal printer control unit 80 receives the detection signal from the third sensor 50c, the motor control unit 60 further conveys the recording paper 2a by a predetermined number of drive pulses. Then, the motor control unit 60 presses the pinch roller 8 against the grip roller 7 via the recording paper 2a. This state is shown in FIG.

  Further, the motor control unit 60 conveys the recording paper 2a, and when the recording paper 2a reaches the fifth sensor 50e, the fifth sensor 50e outputs a detection signal. When the thermal printer control unit 80 receives the detection signal from the third sensor 50e, the motor control unit 60 further conveys the recording paper 2a by a predetermined number of drive pulses. Thereby, the recording paper 2a is conveyed to the printing start position. Further, the motor control unit 60 rotates the ink sheet winding bobbin 3 and the ink sheet winding bobbin 4 to convey the yellow (Y) screen of the ink sheet 5 to the printing position. Further, the motor control unit 60 presses the platen roller 6 against the thermal head 1 via the recording paper 2 a and the ink sheet 5. This state is shown in FIG. Note that the recording paper 2a does not reach the discharge port 16 in a state where the recording paper 2a is conveyed to the printing start position.

  Next, in step S107 in FIG. 8, printing is started on the second main surface (that is, the front surface) of the recording paper 2a. That is, in the state of FIG. 15, the motor control unit 60 conveys the thermal head 1 while conveying the ink sheet 5 and rotating the platen roller 6 and the grip roller 7 to rewind the recording paper 2a. Yellow (Y) printing is performed by heating. The recording paper 2a and the ink sheet 5 are conveyed by a predetermined number of drive pulses, and yellow (Y) printing is completed.

  Next, the motor control unit 60 releases the pressure bonding between the platen roller 6 and the thermal head 1, rotates the grip roller 7, and conveys the recording paper 2a to the position shown in FIG. At this time, the paper feed rollers 9 and 11 and the recording paper roll 2 are also rotated in synchronization with the grip roller 7. Further, the motor control unit 60 rotates the ink sheet winding bobbin 3 and the ink sheet winding bobbin 4 to convey the magenta (M) screen of the ink sheet 5 to the printing position. Then, the magenta (M) printing is performed by the same operation as the yellow (Y) printing. Thereafter, the same printing operation is repeated to print cyan (C) and overcoat (OP). Thus, printing on the second main surface (that is, the front surface) of the recording paper 2a is completed.

  After the printing on the second main surface (that is, the front surface) of the recording paper 2a is completed, the motor control unit 60 keeps the pinch roller 8 in pressure contact with the grip roller 7, and the grip roller 7, the paper feed roller 9, and the recording paper roll. 2 is rotated, and the recording paper 2 a is conveyed toward the discharge port 16. When the recording paper 2a reaches the fifth sensor 50e, the fifth sensor 50e outputs a detection signal. The detection signal from the fifth sensor 50e is used for monitoring a paper jam. The motor control unit 60 presses the pinch roller 15 against the paper discharge roller 14 via the recording paper 2a, rotates the paper discharge roller 14, the grip roller 7, the paper feed roller 9, and the recording paper roll 2, and further The recording paper 2a is conveyed by a predetermined number of drive pulses. As a result, the printed portion of the recording paper 2a is exposed from the discharge port 16 to the outside of the thermal printer 100 housing. Then, the recording paper 2a is cut by the cutter 16a provided at the discharge port 16, and the printed matter is discharged from the discharge port 16 (step S108 in FIG. 8).

<Operation of curl correction mechanism>
At the time of thermal transfer, the ink sheet 5 and the recording paper 2 a are once heat-pressed between the thermal head 1 and the platen roller 6. Thereafter, the ink sheet 5 that has passed between the thermal head 1 and the platen roller 6 is sequentially guided by the peeling roller 31 and the guide roller 32 and then wound on the winding bobbin 3 (FIG. 1). At this time, the ink sheet 5 is peeled from the recording paper 2 a by being pulled in a direction from the position sandwiched between the thermal head 1 and the platen roller 6 toward the peeling roller 31. If an appropriate tension is not applied to the ink sheet 5 at this time, the ink sheet 5 may not be completely peeled from the recording paper 2a, that is, a peeling failure may occur, or the ink sheet 5 may be wrinkled.

  In order not to give an extra change in the conveying speed to the recording paper 2a, there is no arrangement between the thermal head 1 and the grip roller 7 that makes contact with the recording paper 2a, and the distance between the thermal head 1 and the grip roller 7 is made as short as possible. It is desirable to do. Further, it is desirable to avoid excessive tension fluctuations on the ink sheet 5. In the present invention, in order to keep the conveyance speed of the recording paper 2a and the tension of the ink sheet 5 stable, the curl correction mechanism 40 is disposed upstream of the thermal head 1 in the feeding direction in which the recording paper 2a is printed. ing.

  In the hair setting method, after curling or straightening the hair, heat is applied to fix it in its shape. Similarly, in this embodiment, as shown in FIG. 5, the recording paper 2 a is wound around the platen roller 6 in the direction opposite to the curl, and the curl correction is performed using the heat of the thermal head 1.

  In the present embodiment, since the curl correction roller 41 is movable, the length along which the recording paper 2a extends along the platen roller 6 (the winding amount of the recording paper 2a) can be easily changed. Thereby, the adjustment of the curl correction amount of the recording paper 2a can be freely managed. For example, the winding diameter detection unit 72 that detects the winding diameter of the recording paper roll 2 detects the winding diameter of the recording paper roll 2, and the curl amount estimation unit 46 estimates the curl amount of the recording paper 2a. The amount of correction can be determined. In addition, as shown in FIG. 4, by setting the curl correction to the off state, the conveyance path of the recording paper 2a becomes almost straight, the conveyance speed can be increased, and highly reliable recording paper conveyance that is less likely to cause jamming. It becomes possible.

  In step S103 of FIG. 8, when printing is performed on the first main surface (that is, the back surface) of the recording paper 2a, that is, the inner surface of the recording paper roll 2, the curl correction mechanism 80 corrects the curl of the recording paper 2a. To do. FIG. 16 is a flowchart showing the operation of the curl correction mechanism. The operation of the curl correction mechanism in step S103 in FIG. 8 will be described.

  First, in step S1031, the winding diameter of the recording paper roll 2 is measured. This is performed by the winding diameter detection unit 72 detecting the winding diameter of the recording paper roll 2. In step S 1032, the curl amount estimation unit 46 calculates the curl correction amount from the winding diameter of the recording paper roll 2. This is done, for example, by referring to FIG. Next, in step S1033, the curl correction mechanism control unit 47 calculates the rotation amount of the holding member 43 based on the curl correction amount, and transmits the rotation amount to the thermal printer control unit 80. In step S 1034, the motor control unit 60 rotates the holding member 43 by driving the curl correction motor 44 based on the control instruction including the rotation amount of the holding member 43 sent from the thermal printer control unit 80. Move.

  Thereafter, the rotation amount of the holding member 43 of the curl correction mechanism 40 is based on the position of the curl correction OFF state in FIG. As shown in FIG. 17, generally, when the winding diameter of the recording paper roll 2 is large, the curling amount of the recording paper 2a is small, and when the winding diameter is small, the curling amount of the recording paper 2a is large. Therefore, if the winding diameter of the recording paper roll 2 is large, the rotation amount of the holding member 43 is reduced to reduce the curl correction amount, and if the winding diameter is small, the rotation amount of the holding member 43 is set to increase the curl correction amount. Enlarge. As described above, by changing the curl correction amount according to the change in the winding diameter of the recording paper roll 2, the curling of the recording paper 2a can be corrected appropriately.

  FIG. 18 is a diagram illustrating timings of the conveyance direction of the recording paper 2 a, the on / off of the heater 30 of the thermal head 1, and the rotation amount of the holding member 43. The operation timing control of the curl correction mechanism 40 will be described with reference to FIG. It may be considered that the curl correction amount is obtained by the product of the rotation amount of the holding member 43 and the ON time of the heater 30 provided in the thermal head 1.

  In FIG. 18, the maximum amount of rotation indicates that the holding member 43 is in the position of FIG. Further, the minimum rotation amount indicates that the holding member 43 is in the position shown in FIG. (A) in FIG. 18 is an example in which the rotation amount of the holding member 43 is always kept at the maximum from the beginning to the end of the printing operation. In this case, the curl correction amount is always maximized.

  18B shows an example in which the rotation amount of the holding member 43 is maximized only when the heater 30 is on, and the rotation amount of the holding member 43 is minimized (zero) when the recording paper 2a is rewound. In this case, since the recording paper 2a is not along the platen roller 6 when the recording paper 2a is rewound, the conveyance speed of the recording paper 2a can be increased. That is, it is possible to shorten the total printing time while performing curl correction.

  (C) in FIG. 18 is an example in which the rotation amount of the holding member 43 is maximized only when a specific color (for example, Y) is printed, and the rotation amount is minimized when printing other colors. Here, the specific color may be only one of (Y, M, C, protective layer) or a plurality of colors.

  (D) in FIG. 18 is an example in which the curl correction mechanism 40 is always turned on from the beginning to the end of the printing operation, as in (a). The difference from (a) is that the rotation amount of the holding member 43 is determined based on the winding diameter of the recording paper roll 2. Here, also in (b) and (c), the rotation amount of the holding member 43 may be replaced with the rotation amount based on the winding diameter of the recording paper roll 2.

  (E) in FIG. 18 is an example in which the rotation amount of the holding member 43 is freely changed according to the shade of each color when printing each color of Y, M, C, and overcoat (OP). When the density of the color to be printed is low, the amount of heat of the heater 30 is small, so the amount of rotation of the holding member 43 is increased. On the other hand, when the density of the color to be printed is high, the amount of heat of the heater 30 is large. By doing so, curl correction can be efficiently realized while reducing the conveyance load of the recording paper 2a. If the sum of the colors of the product of the turn-on time of the heater 30 and the rotation amount of the holding member 43 matches the curl correction amount obtained from the winding diameter of the recording paper roll 2, (a), (b) ), (C), (d), the rotation amount of the holding member 43 may be changed according to the density of each color.

  As described above, by reducing the curling of the recording paper 2a, it is possible to realize a highly reliable thermal printer that has good stackability after printing, good printing quality, and is less likely to be jammed.

<Effect>
In the thermal printer 100 according to the present embodiment, the thermal head 1, the platen roller 6 disposed to face the thermal head 1, and the recording paper 2a drawn from the recording paper roll 2 are arranged on the first main surface of the recording paper 2a. A first path 30b that leads to one entrance of a gap between the thermal head 1 and the platen roller 6 and a recording paper 2a that is drawn from the recording paper roll 2 so as to come to the thermal head 1 side are connected to the second of the recording paper 2a. A second path 30c leading to the other entrance of the gap between the thermal head 1 and the platen roller 6 and a switching guide 20 for switching the first and second paths 30b and 30c so that the main surface comes to the thermal head 1 side And a curl correction mechanism 40 for correcting the curl of the recording paper 2a, and the curl correction mechanism 40 is a recording medium that is one of the first and second paths 30b and 30c. In the inner surface printing path through which the recording paper 2a is guided when printing on the inner surface of the roll 2, it is arranged upstream of the platen roller 6, and the curl correction mechanism 40 determines whether or not to correct the curl of the recording paper 2a. Switching is possible.

  In general, in a thermal printer, a thermal head 1 and a grip roller are not arranged between the thermal head 1 and the grip roller 7 so as not to cause an excessive change in the conveyance speed to the recording paper 2a. It is desirable to shorten the distance 7 as much as possible. Further, it is desirable to avoid excessive tension fluctuations on the ink sheet 5. In the present embodiment, the curl correction mechanism 40 is arranged not on the downstream side of the thermal head 1 but on the upstream side in the inner side surface printing path (that is, the first path 30b). It is not arranged between the rollers 7. Therefore, the curl correction mechanism 40 does not hinder the peeling of the ink sheet 5. In addition, the conveyance speed of the recording paper 2a can be kept constant. Further, the curl correction mechanism 40 can freely switch the curl correction mechanism on and off in conjunction with the printing operation. Therefore, it is possible to obtain a thermal printer with good print quality and high reliability.

  In the thermal printer 100 according to the present embodiment, the curl correction mechanism 40 includes a curl correction roller 41 disposed opposite to the platen roller 6 with the recording paper 2a interposed therebetween, and the position of the curl correction roller 41 is conveyed to the recording paper 2a. A correction roller position moving mechanism that moves in a direction that interferes with the path, and the curl correction roller 41 moves so that the curl correction roller 41 interferes with the recording paper 2a, and according to the interference accompanying the movement of the curl correction roller 41 The recording paper 2 a is along the roller surface of the platen roller 6.

  Therefore, in the present embodiment, the curl correction roller 41 can wrap the recording paper 2a around the platen roller 6 in the direction opposite to the curl, and the heat of the thermal head 1 can be used to correct the curl. . Further, the amount of curl correction can be changed by adjusting the amount of movement of the curl correction roller 41.

  Further, in the thermal printer 100 according to the present embodiment, the curl correction mechanism 40 further includes an auxiliary roller 42, and the curl correction roller 41 and the auxiliary roller 42 are held by the same holding member 43, and the correction roller position is moved. When the mechanism moves the holding member 43, the position of the auxiliary roller 42 also moves, and when the auxiliary roller 42 moves to the first position, the auxiliary roller 42 thermally transfers the recording paper 2a that has come out of the inner surface printing path. The auxiliary roller 42 is moved from the entrance of the gap between the thermal head 1 and the platen roller 6 by assisting in guiding to the entrance of the gap between the head 1 and the platen roller 6 and moving the auxiliary roller 42 to the second position. It assists in guiding the discharged recording paper 2a to the path for discharging the recording paper 2a.

  Therefore, when curl correction is not performed, the conveyance path of the recording paper 2a can be switched by moving the auxiliary roller 42 to the first and second positions. Further, by arranging the auxiliary roller 42 on the same holding member 43 as the member on which the curl correction roller 41 is held, the curl correction roller position moving mechanism can be used for the movement of the auxiliary roller 42.

  Further, in the thermal printer 100 of the present embodiment, the curl correction mechanism 40 corrects the curl of the recording paper 2a only when printing either the first main surface or the second main surface of the recording paper 2a.

  Therefore, in the present embodiment, curl correction is performed in the direction opposite to the curl direction of the recording paper 2a only when printing is performed on the back surface of the recording paper 2a (that is, the inner surface of the recording paper roll 2). Therefore, curl correction is not performed during printing on the surface of the recording paper 2a (that is, the outer surface of the recording paper roll 2), so curl correction is performed in the same direction as the curling direction of the recording paper 2a, and curling of the recording paper 2a is performed. There is no increase.

  Further, in the thermal printer 100 of the present embodiment, the curl correction mechanism 40 corrects the curl of the recording paper 2a only when the thermal head 1 is heated.

  Therefore, when the recording paper 2a is rewound, the curling correction mechanism 40 is turned off to increase the conveyance speed when the recording paper 2a is rewound. Therefore, the time required for printing can be shortened.

  Further, in the thermal printer 100 of the present embodiment, the curl correction mechanism 40 corrects the curl of the recording paper 2a only when printing a specific color.

  Therefore, when printing a color other than a specific color, the conveyance speed of the recording paper 2a can be increased by turning off the curl correction mechanism 40. Therefore, the time required for printing can be shortened.

  The thermal printer 100 according to the present embodiment further includes a winding diameter detection unit 72 that detects the winding diameter of the recording paper roll 2, and the curl correction mechanism 40 is based on the winding diameter of the recording paper roll 2. The curl correction amount of the recording paper 2a is adjusted by changing the length of the recording paper 2a along the roller surface of the platen roller 6 by adjusting the movement amount of the roller 41.

  Accordingly, since the curl amount of the recording paper 2a changes according to the winding diameter of the recording paper roll 2, the curling correction of the recording paper 2a is performed based on the winding diameter of the recording paper roll 2, so It is possible to apply curl correction by the amount of curl.

  Further, in the thermal printer 100 according to the present embodiment, the curl correction mechanism 40 adjusts the amount of movement of the curl correction roller 41 based on the winding diameter of the recording paper roll 2 and the heating amount of the thermal head 1 to thereby record the recording paper. The curl correction amount of the recording paper 2a is adjusted by changing the length of 2a along the roller surface of the platen roller 6.

  Accordingly, the curl correction amount is determined according to the product of the length of the recording paper 2 a along the roller surface of the platen roller 6 and the heating amount of the thermal head 1. Therefore, in the present embodiment, the amount of rotation of the holding member 43 (that is, the length of the recording paper 2a along the roller surface of the platen roller 6) is adjusted according to the amount of heating of the thermal head 1, that is, the density of the image. To do. As a result, even if the heating amount of the thermal head 1 changes, a certain amount of curl correction can be performed.

  In the present invention, the embodiments can be appropriately modified and omitted within the scope of the invention.

  DESCRIPTION OF SYMBOLS 1 Thermal head, 2 Recording paper roll, 2a Recording paper, 3 Ink sheet winding bobbin, 4 Ink sheet unwinding bobbin, 5 Ink sheet, 6 Platen roller, 6a Platen roller motor, 7 Grip roller, 7a Conveyance motor, 8, 10, 12, 15 Pinch roller, 9, 11 Feed roller, 9a Feed motor, 13 IC cover, 13a, 13b Dust removal roller, 14 Discharge roller, 14a Discharge motor, 16 Discharge port, 16a Cutter, 20 switching guide, 20a, 21a lever, 20b switching guide motor, 20c, 21c cam, 21 auxiliary guide, 29a, 29b, 29c, 29d, 29e, 29f, 29g, 29h, 29i, 29j, 29k, 29l, 29m, 29n guide roller, 30a introduction path, 30b 1st path, 30c 2nd path, 30d storage path, 30e discharge path, 30 heater, 31 peeling roller, 32 guide roller, 40 curl correction mechanism, 41 curl correction roller, 42 auxiliary roller, 43 holding member, 44 Motor for curl correction, 45 rotation axis, 46 curl amount estimation unit, 47 curl correction mechanism control unit, 50a first sensor, 50b second sensor, 50c third sensor, 50d fourth sensor, 50e fifth sensor, 60 motor control Section, 72 winding diameter detection section, 80 thermal printer control section, 100 thermal printer.

Claims (6)

Thermal head,
A platen roller disposed opposite to the thermal head;
A first path for guiding the recording paper drawn from the recording paper roll to one entrance of a gap between the thermal head and the platen roller so that the first main surface of the recording paper comes to the thermal head side;
A second path for guiding the recording paper drawn from the recording paper roll to the other entrance of the gap between the thermal head and the platen roller so that the second main surface of the recording paper is on the thermal head side;
A switching guide for switching between the first and second routes;
A curl correction mechanism for correcting the curl of the recording paper;
With
The curl correction mechanism is disposed upstream of the platen roller in an inner surface printing path through which the recording paper is guided when printing on the inner surface of the recording paper roll of the first and second paths. ,
The curl correction mechanism can switch whether or not to correct the curl of the recording paper,
The curl correction mechanism is
A curl correction roller disposed opposite to the platen roller across the recording paper;
A correction roller position moving mechanism that moves the position of the curl correction roller in a direction that interferes with the conveyance path of the recording paper;
With
The curl correction roller moves and the curl correction roller interferes with the recording paper, and the recording paper follows the roller surface of the platen roller in response to the interference accompanying the movement of the curl correction roller,
The curl correction mechanism further includes an auxiliary roller,
The curl correction roller and the auxiliary roller are held by the same holding member,
The position of the auxiliary roller is also moved by moving the holding member by the correction roller position moving mechanism,
When the auxiliary roller moves to the first position, the auxiliary roller assists in guiding the recording paper that has exited from the inner surface printing path to the entrance of the gap between the thermal head and the platen roller,
When the auxiliary roller moves to the second position, the auxiliary roller guides the recording paper that has exited from the entrance of the gap between the thermal head and the platen roller to a path for discharging the recording paper. To assist,
Support over Maru printer. The curl correction mechanism corrects curl of the recording paper only when printing either the first main surface or the second main surface of the recording paper.
The thermal printer according to claim 1 . Only when the thermal head is heated, the curl correction mechanism corrects the curl of the recording paper.
The thermal printer according to claim 1 or 2 . The curl correction mechanism corrects the curl of the recording paper only when printing a specific color.
The thermal printer as described in any one of Claims 1-3 . A winding diameter detecting unit for detecting a winding diameter of a recording paper roll on which the recording paper is wound;
The curl correction mechanism adjusts the amount of movement of the curl correction roller based on the winding diameter of the recording paper roll, and changes the length of the recording paper along the roller surface of the platen roller. Adjusting the curl correction amount of the recording paper,
The thermal printer according to any one of claims 1 to 4. The curl correction mechanism adjusts the amount of movement of the curl correction roller based on the winding diameter of the recording paper roll and the heating amount of the thermal head, and allows the recording paper to follow the roller surface of the platen roller. Adjusting the curl correction amount of the recording paper by changing the thickness,
The thermal printer according to claim 5 .

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