JPH10217517A - Color heat-sensitive printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a margin of a color heat sensitive recording paper without deteriorating images. SOLUTION: A yellow fixing device 30 for fixing a yellow heat-sensitive color generation layer which is thermally recorded first is arranged above a pinch roller 28. Ultraviolet rays are projected to a color heat-sensitive recording paper 16 from both sides of the pinch roller 28. In comparison with a conventional color heat-sensitive printer, margins Lc2 and Lc4 of a leading edge 16a and a trailing edge 16b of the recording paper 16 can be reduced by a length of about half a width Ly of the yellow fixing device 30.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color thermal printer of a reciprocating type, and more particularly to a color thermal printer for reducing the margin of a color thermal recording paper.

[0002]

2. Description of the Related Art On a support, at least three types of thermosensitive coloring layers, for example, a cyan thermosensitive coloring layer, a magenta thermosensitive coloring layer,
2. Description of the Related Art A color thermal printer that prints a full-color image using a color thermal recording paper in which yellow thermal coloring layers are sequentially formed is known. In this color thermal printer, when printing, the thermal head is pressed against the color thermosensitive recording paper, the yellow image is thermally recorded line by line on the yellow thermal coloring layer having the highest thermal sensitivity, and immediately thereafter, the yellow thermal coloring layer is irradiated with ultraviolet rays. To settle. Next, a magenta image is thermally recorded on the magenta thermosensitive coloring layer, and then fixed by irradiating ultraviolet rays. Finally, a cyan image is thermally recorded on the cyan thermosensitive coloring layer to obtain a full-color image.

[0003] Such thermal recording and fixing are performed while the color thermosensitive recording paper moves relative to the thermal head and the fixing device. One of the methods for moving the color thermosensitive recording paper is a reciprocating method. As shown in FIG. 5A, a color thermal printer using this reciprocating system includes a capstan roller 2 driven to rotate by a motor and a pinch roller 3 having a smaller diameter than the capstan roller 2. A roller pair 4 is used. The transport roller pair 4 nips the color thermal recording paper 5 and alternately transports the recording paper 5 in a forward direction from the paper supply side to the paper discharge side and a reverse direction in which the paper is transported from the paper discharge side to the paper supply side. Then, the color thermosensitive recording paper 5 is pressed and heated between the platen roller 6 and the thermal head 7 to sequentially record the three colors of yellow, magenta and cyan.

A fixing unit 9 for yellow and a fixing unit 10 for magenta for fixing the yellow thermosensitive coloring layer and the magenta thermosensitive coloring layer are arranged downstream of the conveying roller pair 4 in the forward direction. These fixing devices 9 and 10 are turned on when the color thermosensitive recording paper 5 is transported in the reverse direction.

As shown in FIG. 6A, there is also a color thermal printer in which a yellow fixing device 9 is arranged between a thermal head 7 and a pair of conveying rollers 4. In this color thermal printer, the ultraviolet rays radiated from the yellow fixing device 9 are arranged so as not to be blocked by the transport roller pair 4 and the thermal head 7, and the color thermal printer shown in FIG. The apparatus size in the transport direction of the thermal recording paper 5 is reduced.

[0006]

As shown in FIG. 5B, in a capstan type color thermal printer using a pair of transport rollers, the leading edge 5a of the color thermal recording paper 5 has a thermal head 7 and a platen roller 6. Passing between
Since thermal recording is performed after being nipped by the transport roller pair 4, the distance L from the platen roller 6 to the transport roller pair 4 is L.
The length La2 obtained by adding the pinching margin α (for example, 1 mm) of the color thermosensitive recording paper 5 by the transport roller pair 4 to a1 becomes a blank portion where the thermal recording cannot be performed, which is formed on the leading edge 5a of the color thermosensitive recording paper 5. . To reduce the margin, La1 may be reduced, but this distance La1 is
Since the minimum gap is added to the radius Rp of the capstan roller 2 and the radius Rc of the capstan roller 2, there is a limit to reducing the value.

In a reciprocating color thermal printer, color thermal recording is performed by the pair of transport rollers 4 until thermal recording on all the thermal coloring layers is completed in order to prevent deviation of three color pixels. It is necessary that the paper 5 is nipped. However, if the yellow fixing device 9 is turned off while the rear end is nipped by the conveying roller pair 4, the portion facing the yellow fixing device 9 is insufficiently fixed. On the other hand, if the yellow fixing device 9 is kept lit, a portion near the magenta fixing device 10 is over-fixed. In order to properly fix the yellow thermosensitive coloring layer, the distance La3 from the transport roller pair 4 to the end of the yellow fixing device 9 (the width Ly of the yellow fixing device 9 + the radius Rn of the pinch roller 3 + the minimum gap).
And the length La4 obtained by adding the pinching allowance α by the conveying roller pair 4
May be a margin formed on the trailing edge 5b of the color thermosensitive recording paper 5. However, there is a problem that the margin La4 is about twice as large as the margin La2 of the leading edge 5a.

The margin La4 of the trailing edge 5b can be reduced by providing a shutter device or the like between the yellow fixing device 9 and the color thermosensitive recording paper 5 to adjust the irradiation amount.
Since the apparatus becomes large-sized and the cost is further increased, it cannot be used for a low-cost color thermal printer.

In the color thermal printer shown in FIG. 6A, as shown in FIG. 6B, a margin Lb4 at the trailing edge 5b is provided.
Can be made smaller than the margin La4 of the above-described color thermal printer by about the width Ly of the fixing unit 9 for yellow. However, the thermal head 7 and the transport roller pair 4
Is longer by the width Ly of the yellow fixing device 9, the margin Lb 2 formed on the leading edge 5 a of the color thermal recording paper 5 is larger than the margin La 2 of the color thermal printer described above. It becomes big.

Japanese Patent Laid-Open Publication No. Hei 8-156299 proposes a color thermal printer which can reduce both the margins at the leading edge 5a and the trailing edge 5b of the color thermal recording paper 5. In this color thermal printer, a capstan roller is provided coaxially outside the platen roller, a pinch roller is provided facing the capstan roller, and a thermal head is arranged between the pinch rollers, and a yellow head is provided on the forward side of these rollers. A fixing lamp and a magenta fixing lamp are arranged. However, in this color thermal printer, the color thermal recording paper is conveyed only at both side edges, so that the conveyance is not stable, and there is a problem that uneven feeding or misregistration occurs and image quality is deteriorated. .

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has as its object to reduce the margin of a color thermosensitive recording paper without deteriorating an image.

[0012]

According to a first aspect of the present invention, there is provided a color thermal printer in which a first fixing device is disposed above or below a pair of transport rollers, and a pair of transport rollers is provided. Electromagnetic radiation is applied to the color thermosensitive recording paper from both sides of one of the rollers.

According to a second aspect of the present invention, in the color thermal printer, the first fixing unit includes two ultraviolet lamps, each of which is disposed so as to sandwich one of the conveying roller pairs.

Further, in the color thermal printer according to the third aspect, the first fixing device is constituted by an ultraviolet lamp bent in a U-shape, and a straight pipe portion of the ultraviolet lamp sandwiches one roller of the conveying roller pair. Are arranged as follows.

[0015]

FIG. 1A schematically shows a color thermal printer according to the present invention. This color thermal printer is
A color thermosensitive recording paper 16 is inserted from an insertion port 15 provided on the right side in the drawing. The color thermosensitive recording paper 16 performs thermal recording and fixing of a full-color image while being reciprocated in the forward direction, which is the insertion direction, and in the reverse direction. The color thermal recording paper 16 on which the thermal recording has been completed is discharged from a discharge port 17 provided on the left side in the figure. In order to reduce the size of the printer, the distance from the insertion port 15 to the discharge port 17 is smaller than the length of the color thermal recording paper 16 in the insertion direction. A part always projects from the insertion port 15 and the discharge port 17.

A thermal head 19 is located behind the insertion slot 15.
And a platen roller 20 are arranged opposite to each other. Further, a reflection type photosensor 21 for detecting the leading edge 16a of the color thermosensitive recording paper 16 and a pair of conveyance rollers 22 are arranged further behind.

The thermal head 19 has a heating element array 19a in which a large number of heating elements are arranged in a line in a direction perpendicular to the direction in which the color thermosensitive recording paper 16 is conveyed.
As shown in the figure, it is movable between a thermal recording position where it is pressed against the color thermosensitive recording paper 16 and a retracted position where it is swung about the shaft attachment portion 24 to release the pressure contact. The heating element array 19a generates heat energy suitable for the thermosensitive coloring layer to be printed. The platen roller 20 is rotatable by a platen shaft 25 and rotates following the transfer of the color thermosensitive recording paper 16.

The transport roller pair 22 is a capstan roller 27 that is rotated in both directions by a motor, and a pinch roller that has a smaller diameter than the capstan roller 27 and is rotatable, and is pressed against the capstan roller 27 by a spring (not shown). 28. The transport roller pair 22 sandwiches the color thermal recording paper 16 inserted from the insertion opening 15 and transports the color thermal recording paper 16 in the forward direction and the reverse direction.

The color thermosensitive recording paper 16 is, as is well known,
On a support, a cyan thermosensitive coloring layer, a magenta thermosensitive coloring layer, and a yellow thermosensitive coloring layer are sequentially provided. Top 1
The yellow thermosensitive coloring layer serving as the thermosensitive coloring layer has the highest thermal sensitivity and develops yellow with a small heat energy. The cyan thermosensitive coloring layer, which is the lowermost third thermosensitive coloring layer, has the lowest thermal sensitivity and develops cyan with a large thermal energy. The yellow thermosensitive coloring layer loses its coloring ability when irradiated with near-ultraviolet light of 420 nm. The magenta heat-sensitive coloring layer, which is the second heat-sensitive color-forming layer, develops magenta color with a thermal energy intermediate between that of the yellow heat-sensitive coloring layer and that of the cyan heat-sensitive coloring layer, and loses its coloring ability when irradiated with 365 nm ultraviolet rays. Further, the color thermosensitive recording paper 16 may be provided with, for example, a black thermosensitive coloring layer to form a four-layer structure. Further, the positions of the thermosensitive coloring layers may be exchanged.

Above the conveying roller pair 22, a yellow fixing device 30 is disposed. This yellow fixing device 3
Reference numeral 0 denotes a rod-shaped ultraviolet lamp 31 that emits near-ultraviolet light of 420 nm, and a reflector 32 that covers the ultraviolet lamp 31 from above and on both sides. Fixing device 30 for yellow
UV light is irradiated on the color thermosensitive recording paper 16 from both sides of the pinch roller 28 to fix the yellow thermosensitive coloring layer after the thermal recording.

In general, the amount of ultraviolet light emitted from the rod-shaped ultraviolet lamp 31 is the largest immediately below the ultraviolet lamp 31, as shown in FIG. However, by arranging the reflector 32 having an appropriate shape around the ultraviolet lamp 31, the irradiation amount around the ultraviolet lamp 31 can be more improved than immediately below the ultraviolet lamp 31 as shown in FIG. Even if the ultraviolet lamp 31 is arranged so as to face the pinch roller 28, the ultraviolet irradiation can be performed from both sides of the pinch roller 28 without decreasing the irradiation amount.

A magenta fixing device 34 is arranged downstream of the yellow fixing device 30 on the forward side. The magenta fixing device 34 includes an ultraviolet lamp 35 that emits ultraviolet light of 365 nm, and a reflector 36 that covers the ultraviolet lamp 35 above and on both sides. The magenta fixing device irradiates the color thermosensitive recording paper 16 with ultraviolet rays to fix the magenta thermosensitive coloring layer after the thermal recording.

The fixing unit 30 for yellow is disposed such that the position where the ultraviolet rays are not blocked by the thermal head 19, that is, the end face 32a of the reflector 32 has the forward protrusion amount Ls of the thermal head 19 in the forward direction. ing. Since the transport roller pair 22 is disposed such that the pinch roller 28 is located directly below the ultraviolet lamp 31, the distance Lc1 between the platen roller 20 and the transport roller pair 22 is determined.
Is Ls + Ly / 2, and the margin Lc2 on the side of the leading edge 16a of the color thermosensitive recording paper 16 is equal to Lc1,
2 is obtained by adding the nip margin α of the color thermosensitive recording paper 16 due to No. 2.

The distance Lc from the pair of conveying rollers 22 to the end surface 32b of the reflector 32 of the yellow fixing device 30
In the portion No. 3, the fixing by the yellow fixing unit 30 is insufficient or overfixed to the trailing edge 16 b of the color thermosensitive recording paper 16. Is the margin Lc4 on the rear edge 16b side of the color thermosensitive recording paper 16.

Thus, the margin Lc2 at the leading edge 16a of the color thermal recording paper 16 is (Ls + Ly) compared to the margin Lb2 at the leading edge of the conventional color thermal printer shown in FIG.
+ Rn)-(Ls + Ly / 2) = Rn + Ly / 2. Further, the margin Lc4 of the trailing edge 16b of the color thermosensitive recording paper 16 is also (Ly) compared to the margin La4 of the trailing edge side of the conventional color thermal printer shown in FIG.
+ Rn) -Ly / 2 = Rn + Ly / 2.

Next, the operation of the above embodiment will be described. The color thermal printer shown in FIG. 1A is connected to, for example, a personal computer. If there is an image or the like to be printed while using the personal computer, the user operates the keyboard of the personal computer and then instructs to start printing. As a result, the print data is sent from the personal computer to the color thermal printer. The color thermal printer temporarily stores print data sent from a personal computer in a built-in memory.

After the print start operation, for example, a message indicating that the print preparation is completed and a message indicating that the color thermal recording paper 16 is to be inserted into the insertion slot 15 of the color thermal printer are displayed on a monitor of a personal computer, for example.

According to the message, color thermal recording paper 1
6 is inserted into the insertion slot 16. When not in use, the thermal head 19 swings about the shaft attachment portion 24 and is moved to a retracted position where the thermal head 19 is not pressed against the platen roller 20. Passing between the head 19 and the platen roller 20,
The leading end abuts on the transport roller pair 22. On the way, the leading edge 16a of the color thermosensitive recording paper 16 is detected by the reflective photosensor 21.

When the reflection type photo sensor 21 detects the leading edge 16a of the color thermosensitive recording paper 16, the motor for the conveying roller pair 22 starts driving in response to the detection signal.
The capstan roller 27 is rotated counterclockwise in the figure. As a result, the pinch roller 28 pressed against the capstan roller 27 rotates clockwise in the clockwise direction, and nips the leading edge 16 a of the color thermosensitive recording paper 16.

At the same time as the nip of the color thermosensitive recording paper 16 by the conveying roller pair 22, the thermal head 19
4 and moves to the thermal recording position, and the color thermosensitive recording paper 1 on the platen roller 20 is moved by the heating element array 19a.
Press 6.

The color thermosensitive recording paper 16 is composed of a pair of transport rollers 2.
It is transported in the forward direction by the forward rotation of No. 2. The platen roller 20 rotates counterclockwise about the platen shaft 25 following the transfer of the color thermosensitive recording paper 16. When the leading edge of the recording area reaches the heating element array 19a while the color thermosensitive recording paper 16 is being conveyed, each heating element generates heat energy corresponding to each pixel of the yellow image, and the yellow image is formed on the yellow thermosensitive coloring layer. Is thermally recorded line by line. The color thermosensitive recording paper 16 on which the yellow image has been thermally recorded is fixed to the yellow fixing device 30 and the magenta fixing device 3.
4, the leading end protrudes from the outlet 16.

When the thermal recording on the yellow thermosensitive coloring layer of the color thermosensitive recording paper 16 is completed, the driving of the thermal head 19 is stopped and the thermal head 19 is moved to the retracted position. Immediately thereafter, the ultraviolet lamp 31 of the yellow fixing device 30 is turned on, and the transport roller pair 22 starts to rotate in the reverse direction, thereby transporting the color thermosensitive recording paper 16 from the rear edge 16 b toward the insertion slot 15.

When the color thermosensitive recording paper 16 is conveyed in the reverse direction, near-ultraviolet light of 420 nm emitted from the ultraviolet lamp 31 irradiates the color thermosensitive recording paper 16 and performs the next thermal recording on the magenta thermosensitive coloring layer. Fix so that yellow does not develop.

The ultraviolet rays radiated from the ultraviolet lamp 31 are blocked by the pinch roller 28. However, as shown in FIG. Since the irradiation amount becomes larger, the thermosensitive coloring layer for yellow can be fixed effectively. Further, the portion of Lc4 heading from the trailing edge 16b of the color thermosensitive recording paper 16 to the front end side is a margin portion where thermal recording cannot be performed due to insufficient fixing or overfixing, but this margin Lc4 is the conventional color thermosensitive recording material. The width is smaller by the width Ly of the yellow fixing unit 30 + the radius Rn of the pinch roller 28 than the margin of the trailing edge of the printer.

When the leading edge of the recording area of the color thermosensitive recording paper 16 is transported again to the position of the heating element array 19a, the transport roller pair 22 stops once, and the ultraviolet lamp 31 is turned off. Then, the thermal head 19 returns to the thermal recording position again, and the transport roller pair 22 rotates forward to transport the color thermal recording paper 16 in the forward direction. The thermal head 19 performs thermal recording by applying thermal energy according to the magenta image to the magenta thermosensitive coloring layer.

When the magenta image has been thermally recorded to the rear end of the color thermosensitive recording paper 16 in the forward direction, the thermal head 1
9 again moves to the retreat position to release the pressing on the color thermosensitive recording paper 16, and the transport roller pair 22 is stopped once. Just like in the case of yellow, the conveying roller pair 22 starts rotating in the reverse direction immediately after that, and at the same time, the ultraviolet lamp 35 of the magenta fixing device 34 is turned on. The magenta fixing device 35 irradiates the color thermosensitive recording paper 16 with ultraviolet light having a wavelength of about 365 nm, and fixes the color so that magenta does not develop color during the next thermal recording of the cyan thermosensitive coloring layer.

When the leading edge of the recording area of the color thermosensitive recording paper 16 is conveyed to the position of the heating element array 19a, the thermal head 19 returns to the thermal recording position as described above. At the same time, the conveying roller pair 22 rotates forward to convey the color thermosensitive recording paper 16 in the forward direction. During this transport, the thermal head 19 thermally records a cyan image on the cyan thermosensitive coloring layer.

When the thermal recording on all the thermosensitive coloring layers is completed, the pair of conveying rollers 22 discharges the color thermosensitive recording paper 16 from the discharge port 17 as it is. Note that the cyan heat-sensitive coloring layer has no fixing property since the coloring heat energy has a value that does not cause coloring in a normal storage state, and the fixing units 30 and 34 do not operate.

In the above-described embodiment, the yellow fixing device 30 is disposed so as to face the transport roller pair 22.
As shown in (A), a yellow fixing device 40 using a small ultraviolet lamp may be arranged so as to sandwich the pinch roller 28. When the width of the yellow fixing device 40 is Ly / 2, the distance Ld1 between the platen roller 20 and the transport roller 22 is Ls + Ly / 2 + Rn, and the margin Ld2 formed on the leading edge 16a of the color thermosensitive recording paper 16
Is Ld1 + α.

The distance Ld3 from the conveying roller pair 22 to the forward end of the yellow fixing device 40 is defined as:
Since the fixing by the yellow fixing unit 30 is insufficiently fixed or excessively fixed on the rear end edge 16b of the color thermal recording paper 16, the nip margin α of the color thermal recording paper 16 by the transport roller pair 22 is set to Ld3. The added length becomes a margin Ld4 on the side of the rear edge 16b of the color thermosensitive recording paper 16.

Thus, in the present embodiment, the margin Ld2 at the leading edge 16a of the color thermal recording paper 16 is (Ls + Ly + Rn)-(Ls + Ly) compared to the margin Lb2 at the leading edge of the conventional color thermal printer shown in FIG. / 2 + R
n) = Ly / 2. The margin Ld4 at the trailing edge 16b of the color thermal recording paper 16 is also the margin Ld at the trailing edge of the conventional color thermal printer shown in FIG.
Compared with a4, it can be reduced by (Ly + Rn) -Ly / 2 = Ly / 2. Further, the size of the color thermal printer in the height direction can be reduced.

Further, in the above embodiment, two small ultraviolet lamps are used so as to sandwich both sides of the pinch roller. However, as shown in FIG.
5 may be bent into a U-shape, and the straight tube portions 45a and 45b of the ultraviolet lamp 45 may be arranged on both sides of the pinch roller 28.

In the above embodiments, the position, shape, etc., of the fixing unit for yellow are changed.
The present invention is applied to a magenta fixing device when, for example, the magenta thermosensitive coloring layer is the uppermost layer of the thermosensitive coloring layers of magenta and cyan and thermal recording is to be performed. Also,
Although the color thermal printer has been described, the present invention is also applicable to the monochrome thermal printer of the present invention.

[0044]

As described above, according to the color thermal printer of the present invention, the first fixing device for fixing the first thermosensitive coloring layer on which thermal recording is performed first faces the conveying roller pair above or below. As a result, the margin between the leading edge and the trailing edge of the color thermal recording paper can be reduced by about half of the width of the first fixing device, as compared with the conventional color thermal printer.

Further, the first fixing device is composed of two ultraviolet lamps having a small diameter, and these are arranged so as to sandwich the pair of conveying rollers, so that the margin of the color thermal recording paper can be reduced and the color thermal printer can be used. The dimension in the height direction can be reduced. Furthermore, since the same configuration can be performed with an ultraviolet lamp bent in a U-shape, the cost can be reduced by reducing the number of ultraviolet lamps.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a configuration of a color thermal printer of the present invention.

FIG. 2 is an explanatory diagram showing a distribution of an irradiation amount by an ultraviolet lamp.

FIG. 3 is a schematic diagram showing a configuration of a color thermal printer according to another embodiment of the present invention.

FIG. 4 is a perspective view illustrating a main configuration of a color thermal printer according to still another embodiment of the present invention.

FIG. 5 is a schematic diagram showing a configuration of a conventional color thermal printer.

FIG. 6 is a schematic diagram showing a configuration of another conventional color thermal printer.

[Explanation of symbols]

 16 Color Thermal Recording Paper 19 Thermal Head 20 Platen Roller 22 Conveying Roller Pair 27 Capstan Roller 28 Pinch Roller 30 Yellow Fixing Device 34 Magenta Fixing Device

Claims (3)

[Claims] 1. At least first to first different colors
A third thermosensitive coloring layer is provided on the support, and
For the heat-sensitive coloring layer and the next second heat-sensitive coloring layer, color heat-sensitive recording paper provided with fixability by electromagnetic radiation in a wavelength range specific to each heat-sensitive coloring layer is used. A pair of transport rollers for reciprocating in the forward and reverse directions, a thermal head for heating and coloring each thermosensitive coloring layer in order from the first thermosensitive coloring layer during transport in the forward direction,
A first fixing device for irradiating an electromagnetic beam for fixing the thermosensitive coloring layer, and a second fixing device for irradiating an electromagnetic beam for fixing the second thermosensitive coloring layer; In the color thermal printer, the first fixing device is disposed to face above or below the transport roller pair, and irradiates the color thermal recording paper with electromagnetic rays from both sides of one of the transport roller pairs. Color thermal printer. 2. The apparatus according to claim 1, wherein the first fixing device includes two ultraviolet lamps having a small diameter, and is arranged so as to sandwich one of the conveying rollers.
A color thermal printer as described. 3. The apparatus according to claim 1, wherein the first fixing device comprises an ultraviolet lamp bent in a U-shape, and a straight pipe portion of the ultraviolet lamp is arranged so as to sandwich one of the rollers of the conveying roller pair. The color thermal printer according to claim 1, wherein: