JPH1016339A - Recording paper guide apparatus of thermal printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate the jamming of recording paper in a thermal head when the recording paper is sent to the thermal head. SOLUTION: A movable guide 43 is provided between a feed roller pair 11 and a thermal head 13. The movable guide 43 is constituted of a guide plate main body 43a and a holding plate 43b by bending a thin plate having springiness. The guide plate main body 43a is obliquely inserted in a recording paper passage by the springiness of the holding plate 43b to be set to a guide position and the leading end of recording paper 12 is guided to the lower part of the thermal head 13 at the guide position and the thermal head 13 is fixed to be arranged. A platen roller 14 is provided in a freely liftable manner and displaced between the pressure contact position with a heating element array 13a and a position separated from the array 13a by a platen displaying lever 16. A push-up plate 19 is provided to the platen displacing lever 16. The guide plate main body 43a is upwardly pushed by the push-up plate 19 by the displacement of the platen displacing lever to the pressure contact position to be set to a retracted position from the guide position.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording paper guide device for a thermal printer, and more particularly, to a recording paper nip, which feeds the recording paper to a thermal head and pulls back the recording paper. The present invention relates to a recording paper guide device of a thermal printer for recording a full-color image.

[0002]

2. Description of the Related Art In a color thermal printer, for example, a color thermal printer, a color thermal recording paper is used and a full-color image is recorded in three color planes sequentially. In this color thermosensitive recording paper, a cyan thermosensitive coloring layer, a magenta thermosensitive coloring layer, and a yellow thermosensitive coloring layer are sequentially provided on a base. The yellow thermosensitive coloring layer, which is the uppermost layer, has the highest thermal sensitivity and the lowermost layer. Is the lowest heat sensitivity of the cyan thermosensitive coloring layer. Each thermosensitive coloring layer is recorded in order from the uppermost layer. However, when recording the magenta thermosensitive coloring layer, the recording is performed after the yellow image is recorded so that uncolored components in the yellow thermosensitive coloring layer do not develop color.
Light fixing is performed by irradiating a violet visible ray of 20 nm. Similarly, after recording the magenta thermosensitive coloring layer, the magenta thermosensitive coloring layer is light-fixed by irradiating 365 nm ultraviolet rays. In such a color thermal printer, a transport roller pair composed of a capstan roller and a nip roller is used to improve the precision of feeding the color thermal recording paper, and a full color image is recorded by feeding or pulling back the recording paper three times. . When the leading edge of the recording sheet is guided to the thermal head, the pressure contact between the thermal head and the platen roller is released so that the leading edge of the recording sheet passes smoothly between the thermal head and the platen roller.

[0003]

In a conventional color thermal printer, a platen roller is fixed and a thermal head is moved up and down so that a heating element array of the thermal head is pressed against recording paper to perform thermal recording. ing.
In this method, since the thermal head is moved up and down, the thermal head retreats from the recording paper path at the retracted position. Therefore, there is a possibility that the leading end of the recording paper is locked by a gap or a step between the thermal heads and a paper jam occurs. There is an advantage that it becomes less. On the other hand, the transport load fluctuation due to the vertical movement of the thermal head is larger than that due to the vertical movement of the platen roller, and thus there is a problem that the print tends to be uneven. On the other hand, as shown in FIG. 7, by fixing the thermal head 2 and moving the platen roller 3 up and down by the roller shift mechanism 4, it is possible to suppress fluctuations in additional conveyance and reduce print unevenness.

However, when the platen roller 3 is moved up and down while the thermal head 2 is fixed, a gap 5a, a step 5b, etc. are provided between the thermal head main body 2a and a cover 2b for protecting a wiring portion and the like below the main body 2a. When the recording paper 6 is fed by the pair of conveying rollers 7, there is a problem that the leading end 6a of the recording paper is locked by the gap 5a and the step 5b. On the other hand, it is conceivable to create a thermal head having no gap 5a or step 5b, but in this case, there is a problem that the manufacturing cost is increased.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and is intended to prevent the leading end of the recording paper from being locked in a gap or a step between the thermal head and the protective cover even when the thermal head is fixed. It is an object of the present invention to provide a recording paper guide device for a thermal printer.

[0006]

In order to achieve the above object, a recording paper guide device for a thermal printer according to the present invention is arranged between a pair of transport rollers and a thermal head, and performs recording from the pair of thermal rollers. A movable guide movably mounted between a guide position for guiding the paper below the thermal head and a retracted position for retracting from the recording paper path during recording of the thermal head; And a guide displacement member for displacing the movable guide from the guide position to the retracted position by a displacement at the time of switching from the retracted position to the crimping position. According to a second aspect of the present invention, the movable guide is displaced from the retracted position to the guide position by the guide displacing member when the platen is displaced from the pressing position to the retracted position. Preferably, a guide plate urging means for urging the movable guide is provided on a side opposite to a direction in which the movable guide is displaced by the guide displacement member.
Preferably, the movable guide comprises a guide plate and a holding plate, and at the guide position, the guide plate is inserted obliquely with respect to the recording paper path. Further, it is preferable that the holding plate is formed of a member having a spring property, and the holding plate forms the guide plate urging means. The transport roller pair sends and retracts the recording paper by changing the rotation direction, guides the leading end of the recording paper to the thermal head side with the platen roller in the retracted position when the recording paper is sent out, and performs recording. When the paper is pulled back, it is preferable that the platen roller be set at the pressure contact position to perform thermal recording.

[0007]

The leading edge of the recording paper is fed toward the thermal head by the pair of conveying rollers. When sending out this recording paper,
The movable guide is set at the guide position, and the platen roller is at the retracted position away from the heating element array of the thermal head. Therefore, when the recording paper is sent to the thermal head side, the leading end of the recording paper obliquely comes into contact with the guide surface of the movable guide, and the recording paper is guided downward by the guide surface. Therefore, the leading end of the recording paper is not locked by a gap or a step between the thermal head main body and the protective cover, and paper jam is prevented. When the recording area of the recording paper has passed the heating element array, the feeding of the recording paper ends, and the recording paper is pulled back. At the time of this retraction, the platen displacement member is displaced to switch the platen roller from the retracted position to the pressure contact position. In addition, the guide displacement member switches the movable guide from the guide position to the retracted position by the displacement of the platen displacement member. In the retracted position, the guide surface of the movable guide is located at a position retracted from the recording paper path, so that the recording paper does not come into contact with the movable guide and the recording paper is pulled back smoothly. During the pullback of the recording sheet, for example, a yellow image is thermally recorded on the recording sheet. When the recording of the yellow image is completed and the leading end of the recording paper approaches the pair of conveying rollers, the pulling back of the recording paper is completed. After the pulling back of the recording paper, the platen roller is displaced from the pressure contact position to the retracted position by the platen displacement member. Since the guide displacement member is also displaced by the displacement of the platen displacement member, the movable guide is switched from the retracted position to the guide position. Thereafter, the recording paper is sent out and pulled back in the same manner.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the side view shown in FIG. 2, a recording paper roll 10 is mounted on a mounting shaft 8 and stored in a roll storage chamber 9 in a roll form. The conveying roller pair 11 is provided between the recording paper roll 10 and the color thermal recording paper 12.
And sends it out to the thermal head 13.
The transport roller pair 11 includes a capstan roller 11a, a nip roller 11b disposed above the capstan roller 11a, an auxiliary nip roller 11c disposed diagonally above the capstan roller 11a, and a roller shift mechanism 11d. Nip roller 11b and auxiliary nip roller 11
“c” is moved up and down by the roller shift mechanism 11 d, and enters the nip state of the recording paper 12 when descended, and enters the nip release state of the recording paper 12 when elevated.

The auxiliary nip roller 11c is arranged at a position rotated counterclockwise from the nip roller 11b by, for example, 60 degrees around the capstan roller 11a. Therefore, the recording paper 12 is
1b and the auxiliary nip roller 11c are always wound around the capstan roller 11a at 60 degrees. Thereby, the curl is removed by curving the recording paper 12 to the side opposite to the roll form of the recording paper 12. Note that the winding angle is not limited to 60 degrees, and can be appropriately changed depending on the thickness of the recording paper 12 or the like.

As is well known, the recording paper 12 is provided with a cyan thermosensitive coloring layer, a magenta thermosensitive coloring layer, and a yellow thermosensitive coloring layer in this order on a support, and the thermal sensitivity of the uppermost yellow thermosensitive coloring layer is reduced. highest. The yellow thermosensitive coloring layer is 4
The coloring ability disappears due to the violet visible light of 20 nm, and the coloring ability of the magenta thermosensitive coloring layer disappears by the ultraviolet ray of 365 nm.

A thermal head 13 and a platen roller 14 are located downstream of the conveying roller pair 11 in the recording paper sending direction.
And are arranged. The thermal head 13 is attached and fixed to a machine frame (not shown). Further, the platen roller 14 is made of hard rubber and is rotatable. The platen roller 14 is used for the up-down mechanism 1
5 so as to be able to move up and down, and to be displaced between a crimping position and a retracted position. As shown in FIG. 1B, during thermal recording, the platen roller 14 is displaced upward to the pressure position, and the heating element array 13a of the thermal head 13
The recording paper 12 is pressed. Further, as shown in FIG. 1A, when the recording paper 12 is sent out, the platen roller 14 is displaced downward to the retracted position, so that the recording paper 12 passes between the thermal head 13 and the platen roller 14. A gap is formed.

The up-down mechanism 15 includes a pair of roller displacement levers 16 and a solenoid 17. The pair of roller displacement levers 16 are rotatably mounted on a machine frame (not shown) via a mounting shaft 18. In addition, a platen roller 14 is rotatably mounted near a distal end of the roller displacement lever 16 via a mounting shaft 14a. Further, a push-up plate 19 as a guide displacement member is formed at the upper end of the roller displacement lever 16. The push-up plates 19 are arranged on both sides of the passage avoiding the position where the recording paper 12 passes so as not to hinder the conveyance of the recording paper 12.

Heating element array 13 of thermal head 13
a, a large number of heating elements are formed in a line shape in the axial direction of the platen roller 14, and each heating element is driven in accordance with image data during thermal recording, so that the recording area of the recording paper 12 is A full-color image is recorded in three color planes. The thermal head 13 includes a head substrate 20 also serving as a mounting plate, a thermal head main body 21 on which a heating element array 13a is formed, a heat radiating plate 22, and a protective cover 23. A heat sink 22 is provided on the head substrate 20.
The thermal head main body 21 is attached via the head substrate 20, and the thermal head main body 2 is
1 is attached to the machine frame. The protective cover 23 is fixed to the head substrate 21 via mounting screws 24, and covers the lower part of the thermal head main body 21 and the head substrate 20 to protect wiring and the like.

As shown in FIG. 2, a cutter 25 is disposed downstream of the thermal head 13. Cutter 25
Cuts the recording paper 12 from the planned cutting line (virtual line) by moving the pair of movable blades 25a up and down, and separates the recording area as a sheet-like print.

A fixing device 30 is disposed downstream of the cutter 25. The fixing device 30 includes a reflector 31, a fixing lamp 32 for yellow, and a fixing lamp 33 for magenta. The fixing lamp 32 for yellow is 4
The yellow thermosensitive coloring layer is fixed by emitting violet visible light in a wavelength range of 20 nm, so that the yellow component is not colored during the next magenta recording. Magenta fixing lamp 33
Emits ultraviolet light in a wavelength range of 365 nm to fix the magenta thermosensitive coloring layer so that the magenta component is not colored during the next cyan recording.

In order to form a path for the recording paper 12 from the recording paper roll 10 to the fixing device 30, a paper feed unit guide plate 4 is provided.
0, lower paper guide plates 41 and 42, movable guide 4
3, and an upper paper guide plate 44 are provided.
The first lower paper guide plate 41 is disposed between the transport roller pair 11 and the platen roller 14. The second paper guide plate 42 is arranged between the platen roller 14 and a paper discharge port (not shown). Movable guide 4
Numeral 3 is disposed above the first lower paper guide plate 41 between the transport roller pair 11 and the thermal head 13, and is mounted on the upper surface of the thermal head 13 via mounting screws 45. The upper paper guide plate 44 is disposed between the thermal head 13 and the paper discharge port.
The second lower paper guide plate 42 and the upper paper guide plate 44 form a pair. Second lower paper guide plate 4
An opening for the cutter 25 and a pair of paper discharge rollers 46 is formed in 2. The upper paper guide plate 44 has openings for the cutter 25, the fixing device 30, and the discharge roller pair 46.

The movable guide 43 is formed by bending a thin plate having a spring property, and has a guide plate main body 43a and a holding plate 43b. The holding plate 43b is bent in an L-shape, a guide plate main body 43a is arranged at one end, and the other end is attached to the thermal head 13 by a mounting screw 45.
It is fixed to the upper surface of. The guide plate main body 43a is arranged obliquely with respect to the path of the recording paper 12 at the guide position, and the leading end of the recording paper 12 comes into oblique contact with the recording paper 12 below the thermal head 13. I will guide you. Therefore, the leading end of the recording paper 12 is not locked in the gap or step between the thermal head main body 21 and the protective cover 23, and the leading end of the recording paper 12 is
Can be smoothly guided under the vehicle.

Both side portions of the guide plate main body 43a are pushed up by the push-up plate 19 when the platen displacement lever 16 is at the crimping position. Thereby, the guide plate main body 43a is brought to the retracted position as shown in FIG. Further, as shown in FIG. 1A, when the platen roller 14 is in the retracted position, the push-up plate 19 is also displaced downward, and does not come into contact with both side portions of the guide plate main body 43a. Board body 43a
Is set to the guide position by the spring property of the holding plate 43b. Thus, the guide plate main body 43a of the movable guide 43 is automatically set to the guide position and the retracted position in conjunction with the displacement of the platen roller 14. Moreover, the movable guide 43
It is not necessary to provide a special shift mechanism or the like, so that the overall configuration can be simplified.

As shown in FIG. 2, the discharge roller pair 46
The roller shift mechanism 46c shown in FIG. 3 is set at a position retracted from the path of the recording paper 12 except when the paper is discharged. When the paper is discharged, the sheet-shaped print is nipped and discharged to the outside from the paper discharge port. I do.

FIG. 3 is a block diagram showing an electrical configuration of the color thermal printer. The operation unit 50 includes a print start key and the like, and various commands are transmitted to the controller 51.
Send to The controller 51 includes a driver 52, a cutter driving unit 53, an up-down mechanism 15, a print control unit 55, a ramp control unit 56, and roller shift mechanisms 11d and 4.
6c, control the counter 57.

The controller 51 sends a rotation direction signal and a driving pulse to the driver 52. This driver 52
By rotating the pulse motor 60 forward or reverse, the conveying roller pair 1
The first capstan roller 11a and the drive roller of the sheet discharge roller pair 46 are rotated forward or backward. The counter 57 starts a counting operation when the tip detection signal of the tip sensor 61 is input, and counts up when the pulse motor 60 rotates forward and counts down when the pulse motor 60 rotates reversely. As shown in FIG.
1 and the thermal head 13.

The cutter driving section 53 moves the movable blade 25a of the cutter 25 up and down, cuts the recording paper 12 from the cut line, and separates the printed portion as a sheet print. The up-down mechanism 15 includes a platen displacement lever 16 and a solenoid 17, and is shown in FIG.
As shown in (1), the platen roller 14 is raised at the press-contact position to press the recording paper 12 against the heating element array 13a of the thermal head 13. In addition, as shown in FIG. 1A, the platen roller 14 is lowered at the retracted position, so that the recording paper 12 is separated from the heating element array 13a. The print control unit 55 includes a memory storing one frame of three-color image data and a head driver, and drives each heating element of the thermal head 13 according to the image data of each color. These heating elements generate heat in accordance with the image data and the color to be recorded, and cause the recording paper 12 to develop a desired density.

The lamp controller 56 controls the emission of the yellow fixing lamp 32 and the magenta fixing lamp 33. The roller shift mechanisms 11d and 46c are constituted by solenoids or the like, and set the transport roller pair 11 and the discharge roller pair 46 in a nip state or a nip release state.

Next, the operation of the above embodiment will be described with reference to the flowchart shown in FIG. After the image data to be printed is captured, the operation unit 50 is operated to give an instruction to print. First, the controller 51 rotates the pulse motor 60 forward through the driver 52, and the recording paper roll 10 is transported by the transport roller pair 11. The recording paper 12 is pulled out from the printer and sent to the thermal head 13. FIG.
As shown in (A), when the recording paper 12 is sent out, the platen roller 14 is set at the retracted position by the up-down mechanism 15. In this retracted position, the push-up plate 19 is also displaced downward, so that the push-up plate 19 does not come into contact with the guide plate main body 43a, and the guide plate main body 43a is brought into the guide position by the spring property of the holding plate 43b. ing. Therefore, since the leading end of the recording paper 12 is guided below the thermal head 13 by the guide plate main body 43a, the leading end of the recording paper 12 may be locked in a gap or a step between the head main body 21 and the protective cover 23. Instead, the leading end of the recording paper 12 can be smoothly fed to the thermal head 13 side.

When the leading edge of the recording paper 12 passes through the leading edge sensor 61, the controller 51 starts counting up the counter 57 from the time when the leading edge is detected. Based on the up-count value, the controller 51 detects that the recording area has passed the heating element array 13a of the thermal head 13, and terminates the sending of the recording paper 12.

Next, the controller 51 rotates the motor 60 in the reverse direction to pull back the recording paper 12, and counts down the counter 57 during the pullback. The controller 51 specifies a recording area based on the down-count value, and records a yellow image line by line on the recording area by the thermal head 13. Before this thermal recording, the controller 51 operates the up-down mechanism 15 to rotate the platen displacement lever 16 as shown in FIG.
The platen roller 14 is set to the pressure bonding position. Since the push-up plate 19 pushes the guide plate body 43a upward by the displacement of the platen displacement lever 16, the guide plate body 43a
Switches from the guide position to the retracted position. Therefore,
During recording, the guide plate main body 43a is retracted from the passage of the recording paper 12, so that the recording paper 12 can be smoothly pulled back without coming into contact with the recording paper 12. Recording paper 12
2, the recording paper 12 pulled back by the conveying roller pair 11 is temporarily stored by winding and loosening in the gap between the recording paper roll 10 and the roll storage chamber 9 as shown by a two-dot chain line in FIG. Is done.

When the leading edge sensor 61 detects the passage of the leading edge of the recording paper 12 after the recording of the yellow image is completed, the pulling back of the recording paper 12 is terminated. The controller 51 resets the count value of the counter 57 based on the leading edge detection signal. Further, the controller 51 includes an up-down mechanism 1
5 to rotate the platen displacement lever 16,
When the platen roller 14 is moved from the pressure-bonded position of FIG.
(A) is displaced to the retreat position. In conjunction with this displacement,
Since the push-up plate 19 is also separated from the guide plate main body 43a,
The guide plate main body 43a is displaced downward by the spring property of the holding plate 43b and is set to the guide position in FIG.

Next, the controller 51 sends the recording paper 12 forward by rotating the pair of conveying rollers 11 forward, and irradiates the recording area with violet visible light by the yellow fixing lamp 32 to optically fix the yellow image. When the light fixing of the yellow image is completed, the controller 51 sets the conveyance roller pair 11
Is reversed, and the recording paper 12 is pulled back. At this time, the magenta image is recorded on the recording area in the same manner as the recording of the yellow image.

Thereafter, in the same manner as the fixing of the yellow image, the magenta image is fixed by feeding the recording paper 12 after recording the magenta image. When fixing the magenta image, the magenta fixing lamp 33 emits light and irradiates the recording area with ultraviolet rays. Since the magenta fixing lamp 33 is disposed in front of the yellow fixing lamp 32, the feeding amount of the recording paper 12 at the time of magenta fixing is smaller than the feeding amount of the recording paper 12 at the time of yellow fixing. I have. Similarly, when the recording paper 12 is pulled back, a cyan image is recorded. Unlike the yellow and magenta coloring layers, the cyan thermosensitive coloring layer does not need to be fixed because it does not have light fixing property, but the unrecorded white portion and the blank portion in the recording area become pale yellow. And, when this part is irradiated with magenta fixing light, light yellow can be bleached to white, so like magenta fixing,
The magenta fixing lamp 33 is turned on, and the recording area is bleached.

During the bleaching, the controller 51 stops feeding the recording paper 12 when the scheduled cutting line of the recording paper 12 is positioned at the cutter 25, and stops the recording paper 1 at the scheduled cutting line.
2 is cut to separate the sheet print from the recording paper 12. After this cutting, the controller 51 puts the sheet discharge roller pair 46 in a nip state by the roller shift mechanism 46c, and discharges only the sheet-shaped print from the discharge port to a discharge tray (not shown).

In the above embodiment, the movable guide 43
Is mounted on the thermal head 13 side. Alternatively, as shown in FIG. 5, a movable guide 67 may be mounted on a stay 65 on the machine frame side by mounting screws 66. Also in this case, the guide plate main body 6 of the movable guide 67 is provided by the press-down plate 69 provided integrally with the platen displacement lever 68.
7A is configured to be pushed down to the guide position in FIG. 5A via the engagement piece 67c. The guide plate body 67a is attached to the stay 65 by a holding plate 67b, and since the holding plate 67b has a spring property, the platen displacement lever 68 is displaced upward as shown in FIG. 5B. The guide plate main body 67a is automatically set to the retracted position when the platen is in the crimping position. The same components as those shown in FIG. 1B are denoted by the same reference numerals.

In the above embodiment, the movable guide 43
Is constituted by a thin plate having a spring property so that it is not necessary to separately provide an urging means. In addition, the movable guide is moved to either the guide position or the retracted position by a separately provided spring member such as a coil spring. You may make it bias to one side.

In the above embodiment, the platen roller 14 is displaced between the pressure contact position and the retracted position by using the platen displacement lever 16, but in addition, as shown in FIG.
The platen roller 14 may be rotatably attached to the slider 70, and may be moved up and down by the elevating mechanism 71. The elevating mechanism 71 may be configured by a combination of a motor and a cam, instead of using a solenoid. Also in this case, a push-up plate 72 is formed on a part of the slider 70 that holds the platen roller 14, and the guide plate main body 43a of the movable guide 43 is pushed up by the push-up plate 72.

In the above embodiment, the nip roller 1
1b and the auxiliary nip roller 11c, the winding angle of the recording paper 12 around the capstan roller 11a is always constant. However, the auxiliary nip roller 11c is omitted, and the capstan roller 11a and the nip roller 1c are simply used.
1b, a transport roller pair may be formed.

In the above embodiment, the recording paper roll 10 is used. However, the present invention may be practiced when a cut sheet type recording paper is used. In the above-described embodiment, the recording paper 12 pulled back by the transport roller pair 11 is stored by loosening the recording paper 12 in the gap around the recording paper roll 10. The recording paper 12 rotated back in the direction may be stored. Further, the recording paper 12 pulled back by forming a free loop between the recording paper roll 10 and the conveying roller pair 11 is formed.
May be temporarily stored.

In the case where the fixing light irradiation area of the optical fixing device 30 has a long length in the recording paper feed direction in the recording paper feed direction and the fixing unevenness occurs at the leading end and the rear end of the recording area, the fixing light irradiation area is It is preferable to provide a shutter for moving in the recording paper sending direction and blocking the fixing light. In this case, the shutter is opened and closed in conjunction with the feeding of the recording paper to make the integrated fixing light amount distribution in the optical fixing area uniform. Further, in addition to the correction of the fixing unevenness by the shutter, the recording paper 12 is sent so that the entire area of the recording area passes through the fixing light irradiation area, and when the recording area passes through the fixing light irradiation area,
The shutter may shield the unrecorded area adjacent to the recorded area from light, thereby preventing the occurrence of uneven fixing and preventing the unrecorded area from being fixed.

In place of the platen roller 14, a fixed plastic template may be used. Further, the positions of the cutter 25 and the optical fixing device 30 may be appropriately changed. Further, in the above embodiment, the present invention is applied to a color thermal printer. However, the present invention may be applied to a sublimation type or fusion type color thermal transfer printer. The recording paper can be smoothly fed to the thermal head without stopping.

The conveying roller pair 11 in FIG. 2 is a paper feeding roller pair, another conveying roller pair is provided between the thermal head 13 and the cutter 16, and the direction of the thermal head 13 is opposite to that in FIG. Thus, the recording may be performed when the recording paper 12 is sent out. Also in this case, a movable guide is provided between the transport roller pair and the thermal head 13, and the movable guide is displaced between the retracted position and the guide position in conjunction with the displacement of the platen displacement lever. Is also good.

[0039]

According to the present invention, a movable guide is provided between the transport roller pair and the thermal head, and the movable guide is displaced between the guide position and the retracted position in conjunction with the displacement of the platen displacement member. The movable guide can be changed from the guide position to the retracted position only by switching the movable platen from the retracted position to the print position, for example. Therefore, when the recording paper is fed to the thermal head, the platen roller is set to the retracted position and the movable guide is set to the guide position, so that the recording paper can be smoothly fed to the thermal head. Furthermore, at the time of feeding, the leading end of the recording paper is guided below the thermal head by the movable guide, so that the leading end of the recording paper is not locked in a gap or a step between the thermal head main body and the cover. Can be prevented.

Further, since the guide plate urging means for urging the movable guide is provided on the side opposite to the direction of displacement of the movable guide by the guide displacement member, the displacement of the movable guide by the guide displacement member can be easily restored. .

In the guide position, the guide plate is inserted obliquely with respect to the passage of the recording paper so that the leading end of the recording paper is guided below the thermal head. Therefore, the leading end of the recording paper is not locked, so that paper jam can be reliably prevented.

A holding plate is formed from a member having a spring property,
By configuring the guide plate urging means with this holding plate, there is no need to separately provide a spring member such as a coil spring, and the configuration can be simplified.

The transport roller pair feeds and pulls back the recording paper by changing the rotation direction, and guides the leading end of the recording paper toward the thermal head with the platen roller at the retracted position when the recording paper is fed out. When the recording paper is pulled back, thermal recording is performed with the platen roller in the pressure contact position, so that in the case of a fixed type thermal head in a full-color printer that alternately sends and pulls back the recording paper, the thermal head The tip does not lock,
Paper jam can be prevented.

[Brief description of the drawings]

FIGS. 1A and 1B are schematic diagrams showing a main part of a color thermal printer embodying the present invention, in which FIG. 1A shows a state in which the leading edge of a recording sheet is fed to a thermal head side, and FIG. This shows a state in which thermal recording is being performed.

FIG. 2 is a side view schematically showing the entire color thermal printer.

FIG. 3 is a block diagram illustrating an electrical configuration of the color thermal printer.

FIG. 4 is a flowchart illustrating a processing procedure in the color thermal printer.

FIGS. 5A and 5B are schematic diagrams showing a main part of a color thermal printer using another movable guide, wherein FIG. 5A shows a state in which the leading end of a recording paper is fed to a thermal head side, and FIG. Is drawn back to perform the thermal recording.

FIGS. 6A and 6B are schematic views showing a main part of a color thermal printer using a slider, wherein FIG. 6A shows a state in which the leading end of a recording sheet is sent to a thermal head side, and FIG. This shows a state where thermal recording is being performed.

FIG. 7 is a schematic diagram showing a main part of a color thermal printer in which a thermal head is fixed and a platen roller is moved up and down by a roller shift mechanism.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Recording paper roll 11 Conveyance roller pair 11a Capstan roller 11b Nip roller 11c Auxiliary nip roller 11d Roller shift mechanism 12 Recording paper 13 Thermal head 14 Platen roller 16 Platen displacement lever 19,72 Push-up plate 25 Cutter 30 Fixing device 32 Yellow fixing lamp 33 Magenta fixing lamp 43, 67 Movable guide 43a, 67a Guide plate main body 43b, 67b Holding plate 69 Depressing plate 70 Slider

Claims (6)

[Claims] 1. A platen that can be displaced between a pressure bonding position for pressing recording paper against a heating element array of a thermal head and a retracted position separated from the heating element array, and the platen is selectively moved to a pressure bonding position and a retracted position. A recording paper guide device of a thermal printer that nips the recording paper by a pair of conveying rollers and feeds the recording paper to a thermal head to perform thermal recording, wherein the platen is disposed between the pair of conveying rollers and the thermal head. ,
A movable guide movably mounted between a guide position for guiding the recording paper from the pair of transport rollers below the thermal head and a retracted position for retracting from the recording paper passage during recording by the thermal head; and the platen displacement member. And a guide displacing member for displacing the movable guide from the guide position to the retracted position by a displacement when the platen is switched from the retracted position to the pressure bonding position. Guide device. 2. A platen which can be displaced between a pressing position at which recording paper is pressed against the heating element array of the thermal head and a retracted position separated from the heating element array, and the platen is selectively placed at the pressing position and the retracted position. A recording paper guide device of a thermal printer that nips the recording paper by a pair of conveying rollers and feeds the recording paper to a thermal head to perform thermal recording, wherein the platen is disposed between the pair of conveying rollers and the thermal head. ,
A movable guide movably mounted between a guide position for guiding the recording paper from the pair of conveying rollers below the thermal head and a retracted position for retracting from the recording paper passage during recording of the thermal head; And a guide displacement member that is provided on the displacement member and that displaces the movable guide from the retracted position to the guide position by a displacement when the platen is switched from the crimping position to the retracted position. Recording paper guide device. 3. The recording paper guide device for a thermal printer according to claim 1, further comprising: a guide plate urging means for urging the movable guide on a side opposite to a direction in which the movable guide is displaced by the guide displacement member. A recording paper guide device for a thermal printer. 4. The recording paper guide device for a thermal printer according to claim 3, wherein said movable guide comprises a guide plate and a holding plate for holding said guide plate. A recording paper guide device for a thermal printer, wherein the recording paper guide device is inserted obliquely into the passage. 5. A recording paper guide device for a thermal printer according to claim 4, wherein said holding plate is made of a member having a spring property, and said holding plate constitutes said guide plate urging means. Recording paper guide device for printer. 6. The recording paper guide device for a thermal printer according to claim 1, wherein said pair of transport rollers feeds and pulls back the recording paper by changing a rotation direction, and the recording roller guides the recording paper. The recording of a thermal printer is characterized in that the platen roller is set to the retracted position at the time of feeding, the leading end of the recording sheet is guided to the thermal head side, and when the recording sheet is pulled back, the platen roller is set at the pressure contact position to perform thermal recording. Paper guide device.