JP2004042276A - Color thermal printer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To shorten a printing time without enlarging the size of an optical fixing unit. <P>SOLUTION: The color thermal printer 10 comprises optical fixing units 18 and 19 for M and YM. Xe lamps 26 and 27 including an yellow fixing light (about 420 nm) and a magenta fixing light (about 365 nm) in the emission wavelength bands are employed as the fixing light sources of the fixing units 18 and 19. When yellow fixing is performed, only the Xe lamp 27 for YM is lighted and a filter 31 is inserted in order to cut the magenta fixing light in the light emitted from the Xe lamp 27. When magenta fixing is performed, the Xe lamp 27 is lighted together with the lamp 26 for M. Since fixing power of magenta is enhanced, carrying speed of a color thermal recording sheet 11 can be enhanced. To the contrary to a case where an extra lamp dedicated to magenta is employed, size of the optical fixing unit is not increased. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a color thermal printer that records a full color image by performing thermal recording and light fixing on a color thermal recording paper.
[0002]
[Prior art]
There is known a color thermal printer that uses a color thermosensitive recording paper in which three thermosensitive coloring layers of yellow, magenta, and cyan are formed in order from the upper layer on a support and thermally records a full color image. The color thermal printer includes a thermal head extending in the main scanning direction. While the color thermal recording paper is conveyed in the sub-scanning direction, each thermal color developing layer is heated by the thermal head to sequentially display three color images. Make a thermal recording.
[0003]
The yellow thermosensitive coloring layer is colored yellow by heating, and is provided with a light fixing property for yellow fixing light, which is blue-violet light having a wavelength of about 420 nm. When the yellow fixing light is irradiated, the color is developed. Lose ability. The magenta thermosensitive coloring layer is colored magenta by heating, and is provided with a light fixing property with respect to magenta fixing light having a wavelength of about 365 nm. When the magenta fixing light is irradiated, the color development occurs. Lose ability. The heat-recorded yellow and magenta thermosensitive coloring layers are photofixed by irradiating each fixing light by an optical fixing device. This prevents the uncolored portion from being colored when the lower thermosensitive coloring layer is thermally recorded.
[0004]
As a fixing light source of an optical fixing device, two types of fluorescent lamps are generally used: a yellow mercury fluorescent lamp that emits yellow fixing light and a magenta mercury fluorescent lamp that emits magenta fixing light. When yellow is fixed, only the yellow mercury fluorescent lamp is lit, and when magenta is fixed, only the magenta mercury fluorescent lamp is lit.
[0005]
It is known that the fixing sensitivity of the magenta thermosensitive coloring layer is lower than that of the yellow thermosensitive coloring layer. Therefore, in order to increase the fixing ability of the magenta mercury fluorescent lamp, it is conceivable to increase the illuminance per lamp. However, if this happens, the magenta mercury fluorescent lamp deteriorates more rapidly and the yellow mercury fluorescent lamp becomes a Compared to this, the service life is shortened. Therefore, the conveyance speed of the color thermal recording paper is determined so as to secure a fixing light amount necessary for magenta fixing.
[0006]
[Problems to be solved by the invention]
However, in the conventional color thermal printer, since the conveyance speed is determined according to the magenta fixing sensitivity as described above, the printing time is prolonged. Of course, if the illuminance of the magenta fixing light is increased by increasing the number of magenta mercury fluorescent lamps, the conveyance speed can be increased, but this causes a problem that the size of the fixing device increases. Increasing the size of the fixing device not only affects the increase in the size of the printer, but also increases the transport distance of the color thermal recording paper at the time of fixing, leading to a longer printing time.
[0007]
The present invention provides a color thermal printer that can shorten the printing time without increasing the size of the printer.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, the color thermal printer of the present invention develops a yellow thermal coloring layer that develops yellow color and has a light fixing sensitivity to yellow fixing light having a wavelength of about 420 nm, and magenta. Color thermosensitive recording in which at least three thermosensitive coloring layers, a magenta thermosensitive coloring layer having a light fixing sensitivity to magenta fixing light having a wavelength of around 365 nm, and a cyan thermosensitive coloring layer that develops cyan are layered on a support. Using paper, heat each of the thermosensitive coloring layers to thermally record each color image, and irradiate yellow and magenta fixing light to each of the yellow and magenta thermosensitive coloring layers that have been thermally recorded. In the color thermal printer having the light fixing device for performing the light fixing, the light fixing device is configured to emit the yellow fixing light and the magenta in the wavelength range of light emission. A first light source including incident light, a second light source that includes at least the magenta fixing light in a light emission wavelength range, and is different from the first light source, and the first light source and the color thermal recording paper. Magenta fixing light out of the light emitted from the first light source is provided so as to be movable between an insertion position inserted in between and a retracted position retracted from the insertion position. A short-wave cut filter that cuts and transmits only yellow fixing light. When yellow fixing is performed, the filter is disposed at an insertion position, and only the first light source is turned on, while magenta fixing is performed. In this case, the filter is moved to the retracted position and both the first and second light sources are turned on.
[0009]
As each of the first and second light sources, for example, a xenon flash lamp is used.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
The color thermal printer 10 shown in FIG. 1 performs thermal recording of a full-color image and optical fixing of the color thermal recording paper 11 that has been thermal-recorded while reciprocating the color thermal recording paper 11 in the forward direction and in the opposite direction. I do.
[0011]
As is well known, the color thermosensitive recording paper 11 has a cyan thermosensitive color developing layer, a magenta thermosensitive color developing layer, and a yellow thermosensitive color developing layer sequentially provided on a support. The yellow thermosensitive coloring layer, which is the uppermost layer, has the highest thermal sensitivity and develops yellow with a small amount of heat energy. The cyan thermosensitive coloring layer, which is the lowermost layer, has the lowest thermal sensitivity and develops cyan with large heat energy. The yellow thermosensitive coloring layer loses its coloring ability when irradiated with yellow fixing light, which is blue-violet light having a wavelength of around 420 nm. The magenta thermosensitive coloring layer develops magenta with intermediate thermal energy between the yellow thermosensitive coloring layer and the cyan thermosensitive coloring layer, and loses its coloring ability when irradiated with magenta fixing light having a near ultraviolet wavelength of around 365 nm. To do. For example, a black thermosensitive coloring layer may be provided on the color thermosensitive recording paper 11 to form a four-layer structure.
[0012]
On the conveyance path of the color thermal recording paper 11, a thermal head 12 and a platen roller 13 that faces the thermal head 12 and supports the color thermal recording paper 11 are arranged. As is well known, the thermal head 12 includes a heating element array 12a in which a large number of heating elements are arranged in a line along the main scanning direction. Each heating element generates thermal energy corresponding to the density of the pixel and thermally records an image of each color of yellow, magenta, and cyan on each thermosensitive coloring layer. The control unit 14 controls the thermal head 12 via the head driver 16.
[0013]
On the downstream side of the thermal head 12 in the forward direction, a conveyance roller pair 17, a magenta light fixing device (hereinafter referred to as M light fixing device) 18, and a yellow / magenta light fixing device (hereinafter referred to as Y / M light fixing device). 19) is arranged.
[0014]
The conveyance roller pair 17 nips the fed color thermal recording paper 11 and conveys it in the sub-scanning direction. The transport roller pair 17 is driven by the transport motor 21 to rotate. As the transport motor 21, for example, a pulse motor that rotates by a predetermined amount according to the number of applied drive pulses is used. The conveyance motor 21 is controlled by the control unit 14 via the motor driver 22. The controller 14 controls the transport amount of the color thermal recording paper 11 by counting the number of drive pulses applied to the transport motor 21. The color thermal recording paper 11 is conveyed at a predetermined constant speed. This conveyance speed is determined according to the fixing ability of each of the optical fixing units 18 and 19.
[0015]
During this conveyance, the color thermal recording paper 3 passes through the thermal head 12 and the optical fixing devices 18 and 19, and thermal recording and optical fixing are performed. The color thermal recording paper 11 that has been subjected to thermal recording and light fixing is cut into a predetermined size by a cutter (not shown) and discharged outside the color thermal printer 10.
[0016]
The optical fixing device includes an M optical fixing device 18, a Y / M optical fixing device 19, a filter 31, a Y illuminance sensor 36, and a lamp control unit 41. The M optical fixing unit 18 and the Y / M optical fixing unit 19 use a xenon flash lamp (hereinafter referred to as Xe lamp) as a fixing light source. As is well known, each of the Xe lamps 26 and 27 for M and Y / M includes a glass tube filled with xenon gas and a pair of electrodes provided at both ends thereof. The stored current is discharged in the glass tube to emit light. The Xe lamp has a feature that it is less temperature-dependent than a commonly used mercury fluorescent lamp and has a high rise speed until reaching a predetermined illuminance.
[0017]
In addition, as shown in FIG. 2, the Xe lamp has a broad spectral characteristic from about 350 nm to about 450 nm, and the wavelength range of light emitted from it includes yellow fixing light and magenta fixing light. . Therefore, the Xe lamp can be used as both yellow and magenta fixing light sources.
[0018]
Unlike the mercury fluorescent lamp, this Xe lamp cannot be lit continuously, but when used as a fixing light source, a predetermined amount of light can be obtained by turning it on intermittently. When the illuminance at the time of one lighting decreases due to deterioration, the predetermined illuminance can be secured by increasing the lighting frequency.
[0019]
Around each Xe lamp 26, 27, a reflector 28 is disposed that reflects the light emitted from each Xe lamp 26, 27 toward the recording surface of the color thermal recording paper 3. The electrodes at both ends of each Xe lamp 26, 27 are connected to a main capacitor in the lamp drive circuit 34, and a trigger electrode is disposed at a position close to the outer peripheral surface of the glass tube. When a trigger voltage is applied to the trigger electrode, the Xe lamps 26 and 27 emit light by discharging the current stored in the main capacitor in the glass tube.
[0020]
The M optical fixing unit 18 is used for magenta fixing, and the Y / M optical fixing unit 19 is used for fixing both yellow and magenta. That is, in yellow fixing, only the Y / M Xe lamp 27 is turned on. On the other hand, the magenta thermosensitive coloring layer has a low fixing sensitivity. Therefore, in magenta fixing, together with the M Xe lamp 26, The Y / M Xe lamp 27 is turned on.
[0021]
In this way, the magenta fixing ability of the optical fixing device is improved by turning on the two Xe lamps 26 and 27 during magenta fixing. Thereby, since the conveyance speed of the color thermal recording paper 11 can be increased, the printing time is shortened. In addition, since the Y / M Xe lamp 27 is also used for fixing yellow, the optical fixing device does not increase in size unlike the case where a lamp dedicated for magenta fixing is added. Furthermore, since the increase in size of the optical fixing device can be suppressed, the transport distance during fixing does not increase, and the fixing time does not increase.
[0022]
The filter 31 is provided with magenta fixing light (near ultraviolet light having a wavelength of around 365 nm) out of light emitted from the Y / M Xe lamp 27 so that an unrecorded magenta thermosensitive coloring layer is not fixed during yellow fixing. ). The filter 31 is inserted between the Y / M optical fixing device 19 and the color thermal recording paper 11, and is movable between an insertion position that covers the opening of the reflector 28 and a retraction position that retreats from the insertion position. Is provided. The filter 31 is driven by a filter moving mechanism 32.
[0023]
The filter moving mechanism 32 is controlled by the control unit 14. The initial position of the filter 31 is set to the insertion position, and the control unit 14 moves the filter 31 to the retracted position in accordance with the magenta fixing timing, and returns to the insertion position again after the magenta fixing is completed.
[0024]
The lighting frequency of each of the Xe lamps 26 and 27 is adjusted by the control unit 14 so as to secure a necessary fixing light amount in accordance with each of the yellow and magenta thermosensitive coloring layers. An M illuminance sensor 34 sensitive to magenta fixing light is disposed at a position facing the Xe lamp 26, and a sensitivity to yellow fixing light is located at a position facing the Xe lamp 27 together with the M illuminance sensor 34. A Y illuminance sensor 36 having the above is disposed. The illuminance sensors 34 and 36 are provided at positions facing the end portions of the Xe lamps 26 and 27, and light from the Xe lamps 26 and 27 toward the illuminance sensors 34 and 36 is blocked by the color thermal recording paper 11. There is nothing.
[0025]
Each illuminance sensor 34, 36 is connected to an A / D converter 37, and sends an analog signal corresponding to the measured illuminance to each A / D converter 37. The A / D converter 37 converts an analog signal into a digital signal, and inputs the digital signal to the lamp control unit 39 in the control unit 14.
[0026]
A ROM 41 is provided in the lamp control unit 39, and the ROM 41 stores target illuminances for fixing yellow and magenta. The lamp control unit 39 compares the actual illuminance Ly measured by the illuminance sensor 36 with the target illuminance Ty at the time of yellow fixing when yellow fixing, and the actual illuminance Ly and the target illuminance Ty are different. Adjusts the lighting frequency so that the measured illuminance Ly of the Xe lamp 27 is equal to the target illuminance Ty.
[0027]
On the other hand, when magenta fixing is performed, the measured illuminances input from the two illuminance sensors 34 and 36 are summed, and the total value Lm is compared with the target illuminance Tm at the time of magenta fixing. In this case, the lighting frequencies of the Xe lamps 26 and 27 are adjusted so that the total value Lm and the target illuminance Tm are equal. This adjustment is performed at a predetermined interval set in advance, and is performed from the start to the end of fixing yellow and magenta. Since the amount of fixing light is adjusted in this way, fixing unevenness does not occur. Further, even when the illuminance at the time of one lighting of the Xe lamp decreases due to the deterioration, the necessary fixing light amount can be obtained, so that insufficient fixing does not occur.
[0028]
The operation of the above configuration will be described below with reference to the flowcharts shown in FIGS. FIG. 3 is a flowchart showing a printing procedure, and FIG. 4 is a flowchart showing a yellow and magenta light fixing procedure.
[0029]
When a print instruction is given, the color thermal recording paper 11 is fed and conveyed in the forward direction. The yellow thermosensitive coloring layer is heated by the thermal head 12 to record a yellow image. The color heat-sensitive recording paper 11 is sequentially sent from the portion where the yellow image is recorded to the Y / M optical fixing device 19 to start yellow fixing.
[0030]
As shown in FIG. 4, at the time of yellow fixing, only the Xe lamp 27 is lit and light fixing of the yellow thermosensitive coloring layer is started. Further, during yellow light fixing, the filter 31 is in the initial position (insertion position), and the magenta fixing light is cut by the filter 31 from the light emitted from the Y / M light fixing device 19. For this reason, the magenta thermosensitive coloring layer is not light-fixed during yellow light-fixing. The lamp control unit 39 compares the measured illuminance Ly sent from the illuminance sensor 36 with the target illuminance Ty stored in the ROM 41, and if there is a difference between the two, the measured value becomes equal to the target value. Adjust the lighting frequency.
[0031]
When yellow thermal recording and light fixing are completed, the Xe lamp 26 is temporarily turned off, the conveyance roller pair 17 is reversed, and the color thermal recording paper 11 is conveyed in the reverse direction and returned to the recording start position. During this conveyance, the filter 31 moves to the retracted position.
[0032]
After returning to the recording start position, the second forward conveyance is started, and thermal recording of magenta is started. On the color thermal recording paper 11, a magenta image is thermally recorded by the thermal head 12, and is sequentially sent from the recorded portion to the M light fixing device 18 and the Y / M light fixing device 19 to start magenta fixing. At the time of magenta fixing, an Xe lamp 27 for Y and M is turned on together with an Xe lamp 26 for M. Compared with the case where only the M Xe lamp 26 is used, the magenta fixing ability is improved, so that the conveyance speed of the color thermal recording paper 11 can be increased, and the printing time is shortened.
[0033]
The lamp control unit 39 compares the total value Lm of the actually measured illuminances sent from the illuminance sensors 34 and 36 with the target illuminance Tm stored in the ROM 41. Adjust the lighting frequency to be equal to the target value.
[0034]
When the magenta thermal recording and optical fixing are completed, the Xe lamps 26 and 27 are turned off, and the color thermal recording paper 11 is returned to the recording start position again. The filter 31 returns to the initial position (insertion position) while the color thermal recording paper 11 is being returned. When the color thermal recording paper 11 is returned to the recording start position, the third forward conveyance is started and a cyan image is thermally recorded. When the cyan image thermal recording is completed, the color thermal recording paper 3 is discharged.
[0035]
In the above embodiment, the Xe lamp is turned off during the return of the color thermal recording paper to the recording start position. However, the color thermal recording paper is returned with the Xe lamp turned on, and the lighting time of the Xe lamp is increased. May be lengthened. In this way, the conveyance speed of the color thermal recording paper can be further increased.
[0036]
In the above-described embodiment, the example in which the Xe lamp is used as the fixing light source of the Y / M optical fixing device and the M optical fixing device has been described. May be. As the fixing light source of the Y / M optical fixing device, it is necessary to include magenta fixing light and yellow fixing light in the light emission wavelength range. For example, a glass tube in which a rare gas is sealed is used as another lamp. And an external electrode type discharge lamp comprising a pair of electrodes provided outside the glass tube. Other than this, any lamp having broad spectral characteristics from about 365 nm to about 420 nm may be used. On the other hand, as the fixing light source of the M light fixing device, it is sufficient that at least magenta fixing light is included. For example, a magenta mercury fluorescent lamp may be used.
[0037]
Further, the combination of the fixing light sources of the Y / M light fixing device and the M light fixing device may not be the same Xe lamp, but may be a combination of different types of lamps. As examples of combinations, an Xe lamp is used as a fixing light source for Y and M, while a magenta mercury fluorescent lamp is used as a fixing light source for M, and the fixing light source for Y and M is Various types are conceivable, such as using an external electrode type discharge lamp and a magenta mercury fluorescent lamp as a fixing light source for M.
[0038]
In the above-described embodiment, an example in which one Xe lamp is provided as each of the Y, M, and M fixing light sources has been described. However, the number of lamps is not limited to one, and a plurality of lamps may be used. The number of the lamps is appropriately selected according to the necessary fixing light quantity.
[0039]
【The invention's effect】
As described above, the color thermal printer of the present invention includes the first light source that includes the yellow fixing light and the magenta fixing light in the light emitting wavelength region, and at least the magenta fixing light in the light emitting wavelength region. And a second light source different from the first light source, an insertion position inserted between the first light source and the color thermal recording paper, and a retracted position retracted from the insertion position. A light fixing device having a short wave cut filter that cuts magenta fixing light out of light emitted from the first light source and transmits only yellow fixing light when in the insertion position; In this case, the filter is disposed at the insertion position so that only the first light source is turned on. On the other hand, when magenta fixing is performed, the filter is moved to the retracted position, and the first and second light sources are moved. Both light sources It is so arranged to light, without increasing the size of the printer can be shortened printing time.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a color thermal printer embodying the present invention.
FIG. 2 is a graph showing spectral characteristics of a Xe flash lamp.
FIG. 3 is a flowchart illustrating a printing procedure.
FIG. 4 is a flowchart illustrating a fixing procedure.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Color thermal printer 11 Color thermal recording paper 12 Thermal head 18 Magenta light fixing device 19 Yellow / magenta light fixing device 26, 27 Xe flash lamp 31 Filter

Claims (2)

A yellow thermosensitive coloring layer that develops yellow and has a light fixing sensitivity to yellow fixing light, which has a wavelength of about 420 nm, and a magenta fixing light that has a light fixing sensitivity to magenta and has a wavelength of around 365 nm. A color heat-sensitive recording paper in which at least three heat-sensitive color forming layers, i.e., a magenta heat-sensitive color developing layer and a cyan heat-sensitive color developing layer that develops cyan, are layered on a support, Color thermal printer provided with a thermal head for thermal recording, and a photofixing device for irradiating yellow and magenta thermosensitive color developing layers with yellow fixing light and magenta fixing light, respectively. In
The light fixing device includes a first light source including the yellow fixing light and the magenta fixing light in a wavelength range of light emission;
A second light source that includes at least the magenta fixing light in a wavelength range of light emission, and is different from the first light source;
The first light source is provided so as to be movable between an insertion position inserted between the first light source and the color thermal recording paper and a retracted position retracted from the insertion position. A filter that cuts magenta fixing light out of light emitted from the light source and transmits only yellow fixing light,
In yellow fixing, the filter is arranged at the insertion position and only the first light source is turned on. On the other hand, in magenta fixing, the filter is moved to the retracted position, and the first and second light sources are turned on. A color thermal printer characterized in that both of the second light sources are turned on. 2. The color thermal printer according to claim 1, wherein each of the first and second light sources is a xenon flash lamp.

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