JPH091836A - Optical fixing unit for color thermal printer - Google Patents

Abstract

PURPOSE: To correct the irregularity of illuminance by a simple structure when ultraviolet lamps have the irregularity of the illuminances and to suppress the occurrence of an instrument error. CONSTITUTION: A shutter plate 70 is provided between ultraviolet lamps 32a and a color thermal recording material 12. The plate 70 is closed by a shutter plate driver 71 immediately after the feeding of the end of the material 12 is stopped by disposing the end of the material 12 at conveying roller pair 20 at the time of optically fixing. The closing speed of the plate 17 is decided to the maximum illuminance of the standards of the lamps 32a, and the plate 70 is closed by the speed. The home position sensor 78 of the plate 70 is provided. If the illuminances of the lamps 32a are decreased as compared with the maximum illuminances of the standards, the mounting position of the sensor 79 is separated from the reflector 40 by the amount corresponding to the decrease.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photo-fixing device for a color thermal printer, and more particularly to a photo-fixing device for a color thermal printer which carries out photo-fixing near the end of a color thermosensitive recording material.

[0002]

2. Description of the Related Art At least three types of thermosensitive coloring layers such as a cyan thermosensitive coloring layer, a magenta thermosensitive coloring layer, and
A color thermal printer is known which prints a full-color image by using a color thermal recording material in which a yellow thermosensitive coloring layer is layered in order. In this color thermal printer,
At the time of printing, the thermal head is pressed against the color thermosensitive recording material, a yellow image is thermally recorded line by line on the yellow thermosensitive coloring layer having the highest thermal sensitivity, and immediately after that, the yellow thermosensitive coloring layer is optically fixed. Next, a magenta image is heat-recorded on the magenta thermosensitive coloring layer, and this is optically fixed. Finally, a cyan image is thermally recorded on the cyan thermosensitive coloring layer to obtain a full-color image.

Such thermal recording and optical fixing are performed while the color thermal recording material is relatively moved with respect to the thermal head and the optical fixing device. With this moving system, the color thermal printer is mainly used in the platen drum system. And reciprocating method. In the platen drum system, the color thermosensitive recording material is wound around a platen drum having a peripheral length corresponding to the length of the color thermosensitive recording material and rotated, and the color thermosensitive recording material is fixed to the platen drum. The tip of the color thermosensitive recording material is clamped by a clamper. This system requires a platen drum having a peripheral length corresponding to the length of the recording material in order to wind the color thermosensitive recording material. Therefore, the platen drum method is suitable for printing about the size of a postcard, and B5, A
In the case of printing in 4 sizes or the like, a platen drum having a large diameter is required to accommodate this, and it becomes difficult to downsize the apparatus. On the other hand, the color thermosensitive recording material is only slightly clamped at the tip, so that the recording surface can be effectively used in this platen drum system.

On the other hand, as shown in FIG. 9, in a reciprocating type color thermal printer, the tip of the color thermal recording material 3 is nipped by a conveying roller pair 2 consisting of an upper pressing roller 2a and a lower driving roller 2b. (In addition to gripping), while carrying in the forward direction of carrying from the paper feed tray 4 side to the paper discharge path 5 side and the reverse direction of carrying from the paper discharge path 5 side to the paper feed tray 4 side alternately, The color thermosensitive recording material 3 is sandwiched between the platen roller 7 and the thermal head 8 to thermally record three colors of yellow, magenta and cyan sequentially.

An optical fixing device 9 including a yellow ultraviolet lamp 9a and a magenta ultraviolet lamp 9b, and a reflector 9c that covers these lamps 9a and 9b is arranged downstream of the conveying roller pair 2 in the forward direction. The thermal recording is performed on each thermosensitive color developing layer while being transported in the forward direction, and the ultraviolet lamps 9a and 9b of the optical fixing device 9 are selectively turned on to transport the light in the forward direction or the reverse direction. Is supposed to do. In this system, it is not necessary to use a platen drum having a peripheral length corresponding to the length of the heat-sensitive recording material 3, and a platen roller 7 having a small diameter can be used, which is advantageous for downsizing of the apparatus. However, in such a reciprocating color thermal printer, the thermal recording material 3 is always sandwiched between the transport roller pair 2 in the transport system having a simple structure in order to prevent the displacement of the three color pixels. There is a need. Therefore, a sandwiching margin L1 sandwiched by the pair of transport rollers 2 is required, and this portion does not reach the optical fixing device, so that fixing cannot be performed, so that it becomes a blank portion.

Further, it is necessary to arrange the two kinds of ultraviolet lamps 9a and 9b side by side, which causes the area of insufficient fixing to be widened in the lamp 9b on the side away from the conveying roller pair 2.
Further, when the end of the recording material 3 is positioned on the conveying roller pair 2 and the feeding of the recording material 3 is stopped, the irradiation light amount is different between the part that reaches the ultraviolet irradiation area first and the part that reaches the ultraviolet irradiation area later. There is unevenness in the amount of optical fixing inside.

Therefore, in the reciprocating type color thermal printer, the image quality is degraded due to unevenness in the optical fixing at the L2 portion. If you want uniform quality on the print screen,
It is necessary to make the above-mentioned L1 and the margin portion L3. As described above, the reciprocating method requires a large margin portion L3, which causes a problem that a printable portion becomes small.
In particular, when the fixing light amount is increased by using a plurality of lamps and the conveyance speed during fixing is increased to shorten the printing time, the ultraviolet irradiation area is further expanded, and thus this blank area is increased. There is a problem of becoming.

In order to reduce the blank area, the electromagnetic radiation is shielded from the optical fixing device by moving between the ultraviolet lamp and the color thermal recording material in the direction opposite to the feeding direction of the color thermal recording material during optical fixing. It is considered to provide a shutter plate that closes. In this case, the shutter plate is closed at the same speed as the feeding speed of the color thermosensitive recording material immediately before the color thermosensitive recording material is stopped immediately after the end of the color thermosensitive recording material is positioned at the conveying roller pair and the feeding is stopped at the time of optical fixing. To
As a result, even if the edge of the recording material reaches the optical fixing area, there is no uneven fixing, and it is possible to secure a large recording area by reducing the blank area.

[0009]

By the way, the illuminance of the ultraviolet lamp used in the optical fixing device varies. Therefore, even if the shutter plate is closed immediately after the color thermosensitive recording material is stopped at almost the same feed speed as before the color thermosensitive recording material was stopped, the same shutter feed speed is used depending on the variation in the illuminance of the ultraviolet lamp. The fixing condition is different, which causes a machine difference. In order to eliminate this machine difference, it is conceivable to change the shutter feed speed for each device according to the illuminance of the ultraviolet lamp, but in this case, a shutter feed speed variable device is required and the device configuration becomes complicated. Become. Moreover, the shutter feed speed must be set optimally for each device, and adjustment is troublesome.

[0010] The present invention is to solve the above-mentioned problems,
An optical fixing device for a color thermal printer, which eliminates unevenness in optical fixing due to variations in the illuminance of the fixing lamp with a simple structure when performing stable optical fixing of the rear end of the color thermal recording material using the shutter plate. The purpose is to provide.

[0011]

In order to solve the above-mentioned problems, an optical fixing device for a color thermal printer according to claim 1 is provided with a reflector for reflecting electromagnetic rays from a fixing lamp to the side of the thermal recording material. The shutter plate is formed longer than the optical fixing area by the reflector and is movable between the color thermosensitive recording material and the reflector in the feeding direction of the color thermosensitive recording material at the time of optical fixing, and the color thermosensitive recording near the end of optical fixing. Immediately after stopping the feeding of the material, a shutter plate driving unit that closes by moving the shutter plate in the direction opposite to the feeding direction of the color thermosensitive recording material at the time of optical fixing so as to shield the electromagnetic rays from the fixing lamp and the reflector. , A home position sensor that detects the home position of the shutter plate, and a home position sensor that holds the fixed position in the feeding direction of the color thermosensitive recording material. There are those comprising a sensor mounting portion freely changed, and a position adjustment unit for finely adjusting the fixed position in the feeding direction of the color heat-sensitive recording material of the sensor mounting portion.

The optical fixing device for a color thermal printer according to a second aspect is the optical fixing device for a color thermal printer according to the first aspect, in accordance with the maximum illuminance among the variations in the illuminance of the fixing lamp, The shutter plate moving speed of the shutter plate drive unit is specified, and the variation of the illuminance of the fixing lamp arranged in the reflector is calculated.If the variation amount is large, the mounting position of the home position sensor is set to the maximum illuminance. In comparison, it is set in the direction away from the reflector.

The optical fixing device for a color thermal printer according to a third aspect is the optical fixing device for a color thermal printer according to the second aspect, in which the mounting position of the home position sensor is set according to the variation amount of the illuminance of the fixing lamp. It is obtained in advance, and the mounting position is displayed on the position adjusting unit in a scale corresponding to the variation amount of the illuminance.

[0014]

When the end of the color thermosensitive recording material is positioned at, for example, the pair of conveying rollers at the time of optical fixing and the feeding is stopped, the shutter plate is closed at a speed substantially equal to the feeding speed before the color thermosensitive recording material is stopped. To be As a result, even if the edge of the recording material reaches the optical fixing area, there is no fixing unevenness in this area, and the blank area is reduced. Therefore, a wide recording area can be secured.

The illuminance of ultraviolet lamps varies. Therefore, even if the closing speed of the shutter plate is set to be almost the same as that of the color thermosensitive recording material, the amount of light fixing light immediately after stopping the feeding of the color thermosensitive recording material becomes small especially in the case of a lamp having low illuminance. , Uneven fixing will occur. Of the UV lamps used in this case,
The shutter plate moving speed of the shutter plate drive unit is specified according to the maximum illuminance. Then, when the illuminance of the ultraviolet lamp disposed in the reflector is low, the mounting position of the home position sensor is set in a direction away from the reflector corresponding to the maximum illuminance corresponding to the decrease in illuminance. This delays the shutter plate from entering the reflector, so that the amount of irradiation light is increased by the amount of this delay and the decrease in illuminance is corrected. Therefore, it is possible to suppress the occurrence of fixing unevenness in the vicinity of the rear end of the color thermosensitive recording material due to variations in the illuminance of the ultraviolet lamp.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 2 showing the outline of a color thermal printer, a color thermal recording material 12 sent from a paper feed tray 11 by a paper feed roller 10 passes through a paper feed passage 13 toward a first conveying roller 14. Be transported. The first conveying roller pair 14 includes a driving roller 14a and a pressing roller 14b.
The color thermosensitive recording material 12 is nipped, and the nip is applied to the platen roller 15 and the thermal head 1.
Send between 6 and.

When the color thermosensitive recording material 12 passes between the platen roller 15 and the thermal head 16, it is conveyed toward the second conveying roller pair 20. The second conveying roller pair 20 is also composed of a driving roller 20a and a pressing roller 20b, and the color thermosensitive recording material 1 is provided between them.
2 is nipped and conveyed.

As is well known, a large number of heating elements 16a are arranged in a line on the thermal head 16. The thermal head 16 is swingable by a mounting shaft 17. Further, a pressing mechanism 18 is linked to the thermal head 16, and the pressing mechanism 18 presses the heating element 16a against the color thermosensitive recording material 12 and a retracted position apart from the color thermosensitive recording material 12 (in the figure). (Indicated by a chain double-dashed line), the thermal head 16 is moved. Also,
Each heating element 16a is controlled by the print controller 19. The print controller 19 stores image data for each color in a built-in frame memory, and heats each heating element 16a according to the color to be recorded and the density of the pixel based on this image data, and the color thermosensitive recording material 1 is printed.
2 is developed at a desired density and printing is performed.

As shown in FIG. 3, in the color thermosensitive recording material 12, a cyan thermosensitive coloring layer 26, a magenta thermosensitive coloring layer 27, a yellow thermosensitive coloring layer 28, and a protective layer 29 are sequentially formed on a support 25. ing. Each of these thermosensitive coloring layers 26
Nos. To 28 are layered from the surface in the order of thermal recording. For example, when recording in the order of magenta, yellow, and cyan, the positions of the yellow thermosensitive coloring layer 28 and the magenta thermosensitive coloring layer 27 are interchanged. To be An opaque coated paper or a plastic film is used as the support 25, and a transparent plastic film is used when an OHP sheet is produced.

The cyan thermosensitive coloring layer 26 contains an electron-donating dye precursor and an electron-accepting compound as main components, and develops a cyan color when heated. Magenta thermosensitive coloring layer 2
No. 7 contains a diazonium salt compound having a maximum absorption wavelength of about 365 nm, and a coupler which thermally reacts with this compound to develop magenta color. When the magenta thermosensitive coloring layer 27 is irradiated with ultraviolet light near 365 nm after thermal recording, the diazonium salt compound is photolyzed and loses its coloring ability. The yellow thermosensitive coloring layer 28 has a maximum absorption wavelength of about 42
It contains a diazonium salt compound having a thickness of 0 nm and a coupler which reacts with the diazonium salt compound to develop a yellow color. When the yellow thermosensitive coloring layer 28 is irradiated with ultraviolet rays in the vicinity of 420 nm, the yellow thermosensitive coloring layer 28 is optically fixed and loses its coloring ability.

As shown in FIG. 2, the second conveying roller pair 20
A guide plate 30 and a photo-fixing device 31 are arranged on the downstream side of the forward feed (feed to the right in the figure). The optical fixing device 31 includes first and second optical fixing devices 32 and 33, a rotating frame 34, a swinging frame 35, and an interlocking mechanism 36 that interlocks these.

The first optical fixing device 32 is composed of two yellow ultraviolet lamps 32a and 33b and a reflector 40. The reflector 40 is an ultraviolet lamp 32.
The color thermosensitive recording material 12 is irradiated with the ultraviolet rays emitted from a and 32b. Similarly, the second optical fixing device 33 is also composed of two magenta ultraviolet lamps 33a and 33b and a reflector 41. The ultraviolet lamps 32a and 32b for yellow radiate ultraviolet rays having an emission peak of approximately 420 nm to optically fix the yellow thermosensitive coloring layer 28, and the ultraviolet lamps 33a and 33b for magenta radiate ultraviolet rays having an emission peak of approximately 365 nm and magenta. Optical fixing of the thermosensitive coloring layer 27 is performed.

The optical fixing devices 32 and 33 are attached to a rotating frame 34, and are alternately set at a fixing position by rotating the rotating frame 34 by 105 degrees. The rotating frame 34 is rotatably attached to the swing frame 35 via a mounting shaft 45. The swing frame 35 is swingably attached to the stay 46 via a swing shaft 47. The swing frame 35 and the rotating frame 34 are linked by an interlocking mechanism 36.

The interlocking mechanism 36 is composed of a motor, a gear train, a clutch portion, etc., which are not shown, and the swing frame 3
The rocking frame 35 is rocked about the rocking shaft 47 within a range of 10 degrees to move the rocking frame 35 between the fixing position shown by the solid line in FIG. 2 and the retracted position shown by the chain double-dashed line. Further, the interlocking mechanism 36 is interlocked with this swinging motion to swing the rocking frame 35.
At the retracted position, the rotating frame 34 is rotated within a range of 105 degrees to set either one of the optical fixing devices 32 and 32 to the optical fixing position.

FIG. 4 is for explaining the movement of the interlocking mechanism 36. From the yellow light fixing state of FIG.
As shown in (B), the swing frame 35 rotates counterclockwise by 10 degrees, and then as shown in (C), the swing frame 3 rotates.
4 rotates 105 degrees in the clockwise direction, and then the swing frame 35 rotates 10 degrees in the clockwise direction to return to the original position as shown in (D), whereby the magenta light fixing state is established. Further, in order to return from the magenta light fixing state to the yellow light fixing state, the rotation or swing operation of each frame 34, 35 is performed as shown in FIGS. 4 (D), (C), (B) and (A). Be seen. The interlocking between the swing of the swing frame 35 and the swing of the swing frame 34 is changed to mechanical control using a cam or a link.
It may be performed by electrical control using an electromagnetic clutch brake or the like.

As shown in FIG. 5, the rotating frame 34 is
Frame body 5 bent in a V shape at an angle of 75 degrees
0 and a frame mounting bracket 51 for mounting the frame main body 50 on the mounting shaft 45. The frame mounting bracket 51 is configured to position the mounting shaft 45 on the line-symmetrical center line of the frame body 50. The frame body 50 has reflectors 40, 41.
And a lamp mounting bracket 52 are attached. As is well known, the lamp mounting bracket 52 holds the contact pins 53 of the bases of the ultraviolet lamps 32a, 32b, 33a, 33b by a built-in contact piece, so that the ultraviolet lamps 32a, 32b in the reflectors 40, 41 ,.
33a and 33b are arranged side by side. A lamp cover 55 is attached to the rotating frame 34 near both ends of the reflectors 40 and 41. The lamp cover 55 covers the ultraviolet lamps 32a, 32b, 33a and 33b near both ends.

A sensor mounting bracket 56, which is bent into a V shape at an angle of 52.5 degrees, is attached to the rotating frame 34. Two light receiving sensors 57 and 58 are mounted on the sensor mounting bracket 56. On the line connecting the light receiving sensor 57 and the ultraviolet lamps 32a, 32b, the light receiving holes 40a, 40b, 50a, 40a, 40b, 50a, are formed in the reflector 40, the frame body 50, and the sensor mounting bracket 56.
56a is opened. Similarly, between the other light receiving sensor 58 and the ultraviolet lamps 33a, 33b, the light receiving holes 41a, 41 are formed in the reflector 41 and the frame body 50.
b and 50b are opened. The positional relationship between the light receiving sensor 57 and the ultraviolet lamps 32a and 32b is such that the irradiation angles of the ultraviolet lamps 32a and 32b are evenly incident on the light receiving surface 57a, the incident angles, the distances, and the entrance holes 40a and 40b.
The opening area of b, etc. are specified. As a result, even if the illuminance of the two ultraviolet lamps 32a and 32b is measured by the single light receiving sensor 57, it is possible to accurately detect variations in the illuminance. The other light receiving sensor 58 is also the light receiving sensor 57.
Similarly, the single light receiving sensor 58 can detect the illuminance variation of each of the ultraviolet lamps 33a and 33b.

Further, the light receiving sensors 57 and 58 and the mounting shaft 45
Between the sensor mounting bracket 56 and the shield plates 59, 6
0 is attached, and the shielding plates 59 and 60 prevent the cords of the ultraviolet lamps 32a, 32b, 33a and 33b from entering the optical paths of the light receiving sensors 57 and 58.

The light receiving sensors 57 and 58 are composed of well-known phototransistors, and the ultraviolet lamps 32a and 3a.
The irradiation light from 2b, 33a and 33b is photoelectrically converted. As shown in FIG. 5, this photoelectric signal is sent to the illuminance measuring circuit 63. The illuminance measurement circuit 63 obtains an illuminance signal based on the photoelectric signal and sends it to the controller 64. Based on this illuminance signal, the controller 64 determines each ultraviolet lamp 32a,
The drive voltages of 32b, 33a and 33b are obtained and sent to the voltage control circuit 65. The voltage control circuit 65 controls each of the ultraviolet lamps 32a, 32b, 33a, 33 based on this drive voltage.
b to drive the ultraviolet lamps 32a, 32b, 33
The illuminances of a and 33b are controlled to be constant. Also,
A display 66 composed of a liquid crystal display board is connected to the controller 64. In addition to the operating state of the color thermal printer being displayed on the display 66, the illuminance variation values of the ultraviolet lamps 32a and 32b attached to the yellow optical fixing device 31 are displayed, as will be described later in detail. ing. The illuminance variation value is determined by the ultraviolet lamps 32a, 3a set in the yellow optical fixing device 32.
It is calculated based on the maximum illuminance within the standard of 2b.

As shown in FIG. 1, at the optical fixing position, a shutter plate 70 for blocking the ultraviolet rays from the optical fixing device 32.
Is provided. The shutter plate 70 is arranged so as to be parallel to the color thermosensitive recording material 12, and is reciprocated by the shutter plate driving unit 71 in parallel to the feeding direction of the color thermosensitive recording material 12. As a result, the shutter plate 70 moves between a closed position that enters the optical fixing position as shown by the two-dot chain line to shield the optical fixing device 32 and an open position that is retracted from the optical fixing position as shown by the solid line. To do.

As shown in FIG. 1, the shutter plate drive unit 71 is composed of a rack 73 attached to the shutter plate 70, a pinion 74 meshing with the rack 73, and a pulse motor 75 for rotating the pinion 74. Pulse motor 75
Is controlled by the controller 64 via the driver 76. The closing speed of the shutter plate 70 is set to be the same as the feeding speed of the color thermosensitive recording material 12. The shutter plate drive unit 71 may be any device that can convert the rotational movement of the motor into the reciprocating motion of the shutter plate 70, and is configured by a slider crank mechanism, a link mechanism, or the like instead of the rack and pinion mechanism. May be.

As shown in FIG. 6, a position detecting piece 77 is formed so as to project on one side edge of the shutter plate 70, and this is detected by a home position sensor 78. The home position sensor 78 is composed of a photo interrupter, and the position detection piece 77 blocks the optical path of the home position sensor 78, so that the shutter plate 70 is provided.
The position of the shutter plate 7 is detected based on this detection signal.
Stop 0 at home position. As a result, the shutter plate 70 can always be returned to a fixed home position.

The fixed position of the home position sensor 78 can be adjusted by a mounting position adjusting portion 79. The mounting position adjusting portion 79 includes a mounting bracket 80 and a mounting screw 8
2, a mounting position adjusting shaft 85, and a scale plate 87. The home position sensor 78 is attached to the guide plate 30 (see FIG. 2) by an L-shaped attachment bracket 80. A long hole 81 is formed in the mounting bracket 80 so that the mounting position of the color thermosensitive recording material 12 in the feeding direction can be changed. A mounting screw 82 is inserted into the long hole 81, whereby the mounting bracket 80 is fixed to the guide plate 30.

A mounting position adjusting shaft 85 is rotatably mounted on the guide plate 30 so as to come into contact with the mounting bracket 80. The mounting position adjustment shaft 85 is the operation shaft 85.
a and an eccentric cam portion 85b eccentrically attached thereto and a mounting shaft portion 85c. By rotating the operation shaft 85a, the lift amount of the eccentric cam portion 85b is changed to change the position of the mounting bracket 80. Fine tune. Further, a coil spring 86 is provided between the mounting bracket 80 and the guide plate 30.
The coil spring 86 urges the mounting bracket 80 toward the mounting position adjusting shaft 85.

A scale plate 8 is provided close to the mounting bracket 80.
7 is provided, and the scale plate 87 has a scale 88.
Is engraved. Further, an instruction line 89 for instructing the scale 88 is engraved on the mounting bracket 80. Scale 88
As will be described later, the yellow ultraviolet lamp 32a,
It is determined according to the variation amount of the illuminance of 32b. For example, when the variation value of the illuminance is detected in 6 stages of "0" to "5", the variation value of the illuminance of 6 stages is determined. Six scale lines 88a are provided. Therefore, the mounting bracket 8 is based on the scale 88.
The fixed position of 0 can be determined, and the home position sensor 78 can be easily positioned according to the variation in illuminance.

The controller 64 is composed of a well-known microcomputer, and counts the number of motor drive pulses of a transport pulse motor (not shown) for feeding the color thermosensitive recording material 12 so as to count the color thermosensitive recording material 12. Is tracked, and each part is sequence-controlled based on this tracking signal.

Next, the operation of the above embodiment will be described.
In the adjustment and inspection process after assembly, as shown in FIG.
The variation in illuminance of the ultraviolet lamps 32a and 32b of the yellow light fixing device 32 is measured. First, by using the light receiving sensor 57 and the illuminance measuring circuit 63, the ultraviolet lamps 32a, 32
The illuminance L of b is measured. The measured illuminance L is sent to the controller 64, and the difference (Lmax-L) from the maximum illuminance Lmax within the standard among the usable yellow ultraviolet lamps 32a and 32b is obtained. This difference (Lmax-L) is converted into an illuminance variation value dL which is a step value in 6-step display, and this illuminance variation value dL is displayed on the display 66. For example, the illuminance variation value dL is from "0" to
Since it is displayed in six levels of "5", the mounting position of the home position sensor 78 of the shutter plate 70 is adjusted based on the scale 88 according to the variation amount. The above adjustment procedure is shown as a flowchart in FIG. As described above, the illuminance variation amount can be easily corrected by converting the illuminance variation amount into the step value to form the illuminance variation value dL and forming the scale 88 corresponding thereto.

FIG. 1A shows the position of the home position sensor 78 when it is adjusted to the maximum illuminance, and FIG.
Indicates the position of the home position sensor 78 when the illuminance variation value dL is displayed as “2”, for example. As a result of the illuminance measurement, when the illuminance variation value dL is “2”, first, as shown in FIG. 6, after loosening the mounting screw 82, the mounting position adjusting shaft 85 is rotated clockwise to mount the mounting bracket 80. After the alignment is made so that the indication line 89 indicates the "2" of the scale 88, the attachment screw 82 is tightened to fix the attachment bracket 80. As a result, as shown in FIG. 1B, the yellow ultraviolet lamp 32a,
When 32b has an illuminance that is two steps lower than the maximum illuminance within the standard, the home position of the shutter plate 70 is separated from the reflector 40 by two scales. Therefore,
Since the entrance of the shutter plate 70 into the reflector 40 is delayed by the amount of the decrease in illuminance, the amount of fixing light is increased by the amount of the delay, and it is possible to eliminate the variation in the amount of fixing light due to insufficient illuminance of the ultraviolet lamps 32a and 32b. Therefore, it is possible to easily compensate for the insufficient illuminance without changing the shutter feed speed and the like, and it is possible to eliminate machine differences due to variations in illuminance of the ultraviolet lamps 32a and 32b.

Printing is performed as follows. First, when the print start switch is operated, as shown in FIG. 2, the color thermosensitive recording material 12 at the uppermost part of the paper feed tray 11 is sent out by the paper feed roller 10, passes through the paper feed passage 13, and then moves to the first position. The sheet is conveyed toward the pair of conveying rollers 14. When the leading end of the color thermosensitive recording material 12 is nipped by the first conveying roller pair 14, the paper feeding roller 10 is in a free state and the feeding of the color thermosensitive recording material 12 is stopped.

The color thermosensitive recording material 12 that has passed between the platen roller 15 and the thermal head 16 by the first conveying roller pair 14 is nipped and conveyed by the second conveying roller pair 20. When the heating element 16a of the thermal head 16 is positioned at the head pressing start position of the color thermosensitive recording material 12 after this nip, the pressing mechanism 18 rotates the thermal head 16 in the clockwise direction to move the heating element 16a to the color thermosensitive recording material. Press 12

In this state, the color thermosensitive recording material 12 is conveyed in the forward direction by the first and second conveying roller pairs 14 and 20, and the tip of the recording area of the color thermosensitive recording material 12 is moved to each heating element 16a during the conveyance. When the temperature reaches, the heat generating elements 16a generate heat energy corresponding to the pixels to thermally record the yellow image on the yellow thermosensitive coloring layer 28 line by line. When recording one pixel, each heating element 16a supplies bias thermal energy for bringing the yellow thermosensitive coloring layer 28 into a state before coloring, and gradation expression thermal energy according to the coloring density, in the color thermosensitive recording material 12. Give to. Further, the yellow ultraviolet lamp 32 is synchronized with the yellow thermal recording.
a and 32b are turned on. This yellow UV lamp 3
Near-ultraviolet rays in the vicinity of 420 nm are applied to the color thermosensitive recording material 12 by 2a and 32b, and the magenta thermosensitive coloring layer 27 is fixed so that yellow does not develop during the next thermal recording.

When the yellow image is thermally recorded up to the rear end of the recording area of the color thermosensitive recording material 12, the thermal head 16 is set to the retracted position apart from the color thermosensitive recording material 12, and the first and second conveyances are performed. Roller pair 14, 20
Is temporarily stopped, and the feeding of the color thermosensitive recording material 12 is stopped. Immediately after this, the shutter plate drive unit 71 operates to close the shutter plate 70. The moving speed of the shutter plate 70 is set to be the same as the feeding speed of the color thermosensitive recording material 12. Therefore, immediately after the feeding of the recording material 12 is stopped, the shutter plate 70 is closed at the feed speed before the feeding of the recording material 12, so that the fixing light amount in the fixing area after the feeding of the recording material 12 is Since the area is fixed with the same amount of light as the area already fixed, uneven fixing is eliminated. As a result, the fixing area after the feeding of the recording material 12 is stopped can be fixed substantially evenly, and therefore, as shown in FIG.
As in the conventional example shown in, the length L4 of the fixing area in the margin L2 can also be the recording area, and as a result,
The recording area can be widened.

When the shutter plate 70 completely covers the reflector 40, the ultraviolet lamps 32a and 32b at the fixing position are turned off. After that, the shutter plate 70 is returned to the original position by the shutter plate driving unit 71. At this time, the movement of the shutter plate 70 is stopped based on the shutter plate detection signal from the home position sensor 78, and the shutter plate 70 stops at the home position. Further, the first and second pairs of conveying rollers 14 and 20 rotate in the opposite directions to convey the color thermosensitive recording material 12 in the opposite directions. Branching section 9 during this transportation
0 causes the trailing end of the color thermosensitive recording material 12 to escape the passage 9
You will be guided to the 1st side. It should be noted that the optical fixing device 30, as close as possible to the pressing roller 20b of the second conveying roller pair 20,
Since 31 is selectively positioned, the non-fixable portion and the non-fixed portion are reduced, and the blank portion resulting from this can be reduced.

When the color thermosensitive recording material 12 is fed in the reverse direction, the optical fixing devices 32 and 33 are switched. As shown in FIG. 4, the interlocking mechanism 36 rotates the motor to first rotate the swing frame 35 by 10 degrees counterclockwise as shown in FIG. 4 (B). After this rotation,
As shown in (C), turn the rotating frame 34 clockwise 1
Rotate 05 degrees. After this rotation, as shown in (D), the swing frame 35 is rotated clockwise by 10 degrees and returned to its original position. As a result, instead of the yellow light fixing device 32, the magenta light fixing device 33 is set at the fixing position.

When the pressing start position of the color thermosensitive recording material 12 is again located at the heating element 16a, the first and second conveying roller pairs 14 and 20 are temporarily stopped. Then, the thermal head 16 returns to the thermal recording position again, and the first and second conveying roller pairs 14 and 20 rotate forward to convey the color thermosensitive recording material 12 in the forward direction. The thermal head 16 applies thermal energy according to a magenta image to the magenta thermosensitive coloring layer 27 to perform thermal recording. Further, the magenta ultraviolet lamps 33a and 33b are turned on in synchronization with the thermal recording. The magenta UV lamps 33a and 33b irradiate the color thermosensitive recording material 12 with near-ultraviolet rays having a wavelength of about 365 nm, and fix the cyan thermosensitive coloring layer 26 so that magenta will not develop color during thermal recording.

When the magenta image is thermally recorded up to the rear end of the recording area of the color thermosensitive recording material 12, the pressing of the thermal head 16 is released, and the first and second conveying roller pairs 14 and 20 are temporarily stopped. After that, as in the case of yellow recording, the first and second pair of conveying rollers 14, 20
Rotates in the opposite direction. For magenta fixing,
Since there is no problem of uneven fixing as in the case of yellow light fixing, it is not necessary to open / close the shutter plate 70 as in the case of yellow recording, since a fixed amount of light or more is applied.

Thereafter, cyan thermal recording is performed in the same manner. Even during this cyan image recording, the magenta ultraviolet lamps 33a and 33b are turned on to continue bleaching. When the thermal recording of the cyan image is completed, the first and second conveying roller pairs 14 and 20 continue to rotate, send the color thermosensitive recording material 12 to the paper discharge passage, and discharge it to a paper discharge tray (not shown). Even during this discharge, the color thermosensitive recording material 1
The magenta ultraviolet lamps 33a and 33b are turned on until 2 is discharged from the optical fixing area. Therefore, the rear end of the color thermosensitive recording material 12 nipped by the conveying roller pair 20 during thermosensitive recording is also bleached. After this bleaching, as shown in FIGS. 4D to 4A, the swing frame 40 and the swing frame 35 are displaced, and the yellow fixing device 30 is set at the fixing position instead of the magenta fixing device 31.

As shown in FIG. 5, the ultraviolet lamps 32a,
When the illuminance of 32b, 33a, 33b fluctuates for some reason, this is monitored by the illuminance measuring circuit 63 via the light receiving sensors 57, 58, and the voltage control circuit 65 suppresses this illuminance fluctuation by the ultraviolet lamp 32a,
The drive voltage of 32b, 33a, 33b is controlled. In this case, each ultraviolet lamp 32a, 32b, 33a, 33
Since b is evenly applied to the light receiving surfaces 57a and 58a of the light receiving sensors 57 and 58, the ultraviolet lamps 32a, 32b, 3
It is possible to accurately detect variations in illuminance of 3a and 33b. Further, even when the lamps 32a, 32b, 33a, 33b are deteriorated or burnt out, this failure occurrence can be reliably detected. Lamps 32a, 32b, 33
When the a and 33b are replaced, the swing frame 35 pivots counterclockwise largely by about 45 degrees, and the lamp can be easily replaced.

In the above embodiment, as shown in FIG. 2, the two optical fixing devices 32 and 33 are selectively set at the fixing position by using the swing frame 35 and the rotating frame 34. However, if there is no space restriction, each optical fixing device 32,
33 may be selectively set at the fixing position. Further, instead of using the rotating frame 34, each optical fixing device may be selectively set at the fixing position by a shift mechanism.

In the above embodiment, as shown in FIG. 6, the mounting position of the sensor mounting bracket 80 was finely adjusted by using the mounting position adjusting shaft 85 having the eccentric cam portion 85b, but in addition to this, it is shown in FIG. You may use such an attachment position adjusting part 99. The mounting position adjusting portion 99 includes a sensor mounting bracket 101, a guide rod 102, a screw rod 103, a holding frame 104, and a dial 105. Sensor mounting bracket 1 for home position sensor 100
01 is held reciprocally by a guide rod 102 and a screw rod 103. Guide rod 102, screw rod 103
Are arranged on the holding frame 104, and the screw rod 103
A dial 105 is fixed to one end of the. Also,
A scale 106 is provided on the holding frame 104, and the fine adjustment of the positioning of the home position sensor 100 can be easily performed by instructing the scale 106 with the instruction section 107 extending from the sensor mounting bracket 101.

In the above embodiment, each fixing device 32, 33 has two
Although the two ultraviolet lamps 32a and 32a are used, the number of the ultraviolet lamps 32a and 32a may be one or three or more.

In the above embodiment, the position adjustment of the home position sensor 78 is performed at the final adjustment stage in the factory shipment of the color thermal printer, but in addition to this, when the ultraviolet lamps 32a and 32b are replaced or the ultraviolet lamps are changed. When the illuminance of 32a, 32b is reduced, the position of the home position sensor 78 may be adjusted periodically.

In the above-described embodiment, assuming that the amount of light emitted from the ultraviolet lamps 32a and 32b in the reflector 40 is substantially uniform in the feeding direction of the color thermosensitive recording material 12, the closing speed of the shutter plate 70 is set to that of the color thermosensitive recording material 12. The color thermal printer has the same setting as the feeding speed, but in addition to this, the illuminance distribution in the feeding direction of the color thermosensitive recording material 12 is not constant, and the closing speed of the shutter plate is changed corresponding to the illuminance distribution. On the other hand, the home position of the shutter plate may be changed according to the variation in the illuminance of the ultraviolet lamp. Also in this case, it is possible to suppress the occurrence of machine differences due to variations in the illuminance of the ultraviolet lamps.

The shutter plate 70 is provided so as to be movable in parallel with the feeding direction of the color thermosensitive recording material 12. Alternatively, the shutter plate can be closed by fixing the shutter plate to the arm and swinging the arm. You may comprise.

Further, in the above embodiment, the members for holding the home position sensors 78, 100 are provided with the scales 88, 1
Although 06 is provided, the scales 88 and 106 may be omitted. In this case, the positions of the home position sensors 78 and 100 may be determined while evaluating the image quality by test printing.

[0056]

According to the present invention, a home position sensor for detecting the home position of the shutter plate, a sensor mounting portion for holding the home position sensor and having a fixed position changeable in the feeding direction of the color thermosensitive recording material, Since the position adjusting portion for finely adjusting the fixing position of the sensor mounting portion in the feeding direction of the color thermosensitive recording material is provided, even if the illuminance of the ultraviolet lamp of the yellow light fixing device varies, the shutter plate of the By changing the home position, it is possible to suppress the occurrence of machine differences due to variations in illuminance.

Further, among the variations in the illuminance of the ultraviolet lamp, the shutter plate moving speed of the shutter plate drive unit is specified in accordance with the maximum illuminance, and the variations in the illuminance of the ultraviolet lamp arranged in the reflector are obtained. When the amount of variation is large, the mounting position of the home position sensor is set in a direction away from the reflector as compared with the case of maximum illuminance, so that the insufficient light amount due to the decrease in illuminance is dealt with by the increase in light amount due to the delay in the entry of the shutter plate. be able to. Therefore, it is not necessary to change the feed speed of the shutter plate in accordance with the variation in the illuminance of the ultraviolet lamp of the optical fixing device, and it is possible to suppress the occurrence of a machine difference due to the variation in the illuminance of the lamp with a simple configuration.

In particular, the mounting position of the home position sensor is obtained in advance according to the variation amount of the illuminance and is displayed on a scale, so that the mounting position of the home position sensor for correcting the variation of the illuminance can be easily known. be able to. Further, by providing the position fine adjustment unit such as the eccentric cam and the screw rod, the position of the home position sensor can be easily adjusted.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing the principle of an optical fixing device for a color thermal printer according to the present invention, in which (A) shows a fixed position of a home position sensor when an ultraviolet lamp with a maximum illuminance within a standard is used, (B) shows the fixed position of the home position sensor when using an ultraviolet lamp with reduced illuminance.

FIG. 2 is a schematic diagram showing a main part of a color thermal printer.

FIG. 3 is a schematic view showing an example of a layer structure of a color thermal recording material used in a color thermal printer.

FIG. 4 is an explanatory diagram showing switching of the optical fixing device.

FIG. 5 is an enlarged schematic view showing a yellow light fixing state.

FIG. 6 is a perspective view showing a shutter plate, a home position sensor, and a position adjusting unit.

FIG. 7 is a flowchart showing a procedure for adjusting a home position position of a shutter plate based on measured illuminance.

FIG. 8 is a perspective view showing a home position position adjusting unit in another embodiment.

FIG. 9 is a schematic view showing a conventional example of a color thermal printer.

[Explanation of symbols]

 12 Color thermal recording material 14, 20 Conveying roller pair 16 Thermal head 32, 33 Optical fixing device 32a, 32b, 33a, 33b UV lamp 40, 41 Reflector 34 Rotating frame 35 Swinging frame 57, 58 Light receiving sensor 64 Controller 70 Shutter Plate 71 Shutter plate driving unit 78,100 Home position sensor 79,99 Mounting position adjusting unit 80,101 Mounting bracket 85 Mounting position adjusting shaft 88,106 Scale 103 Screw rod

Claims (3)

[Claims] 1. At least first to color different colors
While the color thermosensitive recording material on which the third thermosensitive coloring layer is layered is reciprocated, one type of thermosensitive coloring layer is selectively colored by the thermal head, and before the next thermosensitive coloring layer is colored An optical fixing device for a color thermal printer, which comprises a fixing lamp for irradiating an electromagnetic ray peculiar to a thermosensitive coloring layer to fix the thermosensitive coloring layer optically, wherein a reflector for reflecting the electromagnetic ray from the fixing lamp to the thermosensitive recording material side. And a shutter plate that is formed longer than the optical fixing area by this reflector and is movable between the color thermosensitive recording material and the reflector in the feeding direction of the color thermosensitive recording material during optical fixing, and near the end of optical fixing. Immediately after stopping the feeding of the color thermosensitive recording material, the shutter plate is fed to the color thermosensitive recording material during optical fixing so as to shield the electromagnetic rays from the fixing lamp and the reflector. The shutter plate drive part that moves in the opposite direction to the closing direction and closes, the home position sensor that detects the home position of the shutter plate, and the home position sensor are held, and the fixed position can be freely changed in the feeding direction of the color thermosensitive recording material. An optical fixing device for a color thermal printer, comprising: a sensor mounting part; and a position adjusting part for finely adjusting a fixing position of the sensor mounting part in the feeding direction of the color thermosensitive recording material. 2. The method according to claim 1, wherein the first color and the second color are different colors.
While the color thermosensitive recording material on which the third thermosensitive coloring layer is layered is reciprocated, one type of thermosensitive coloring layer is selectively colored by the thermal head, and the color is developed before the next thermosensitive coloring layer is colored. An optical fixing device for a color thermal printer, which comprises a fixing lamp for irradiating an electromagnetic ray peculiar to a thermosensitive coloring layer to fix the thermosensitive coloring layer optically, wherein a reflector for reflecting the electromagnetic ray from the fixing lamp to the thermosensitive recording material side. And a shutter plate that is formed longer than the optical fixing area by this reflector and is movable between the color thermosensitive recording material and the reflector in the feeding direction of the color thermosensitive recording material during optical fixing, and near the end of optical fixing. Immediately after stopping the feeding of the color thermosensitive recording material, the shutter plate is fed to the color thermosensitive recording material during optical fixing so as to shield the electromagnetic rays from the fixing lamp and the reflector. The shutter plate drive part that moves in the opposite direction to the closing direction and closes, the home position sensor that detects the home position of the shutter plate, and the home position sensor are held, and the fixed position can be freely changed in the feeding direction of the color thermosensitive recording material. The shutter is provided with a sensor mounting portion and a position adjusting portion for finely adjusting the fixed position of the sensor mounting portion in the feeding direction of the color thermosensitive recording material, the shutter having a maximum illuminance among variations in the illuminance of the fixing lamp. Specifies the moving speed of the shutter plate of the plate drive unit,
The variation of the illuminance of the fixing lamp arranged in the reflector is obtained, and when the variation amount is large, the mounting position of the home position sensor is set in a direction away from the reflector as compared with that of the maximum illuminance. Optical fixing device for color thermal printers. 3. The optical fixing device for a color thermal printer according to claim 2, wherein the mounting position of the home position sensor is obtained in advance according to the variation amount of the illuminance of the fixing lamp, and this mounting position is used as the variation amount of the illuminance. An optical fixing device for a color thermal printer, characterized in that a scale is displayed on the position adjusting section correspondingly.