JPH04153045A - Color thermal recording system - Google Patents

Abstract

PURPOSE:To record color images thermally in a short time by recording on a third thermal coloring layer by moving a recording material, secondly recording on a second thermal coloring layer by moving the recording material in a reverse direction, and lastly recording on a first thermal coloring layer by moving the recording material in an initial direction. CONSTITUTION:A color thermal recording material 11 is stopped when a fixed length is pulled out and it is cut by a cutter 13 so as to separate to a color thermal recording sheet 14. When the sheet 14 reaches a recording position, a head controller 32 reads out a signal of yellow images from an image input section, sends it to a thermal head 25, records thermally the yellow images on the sheet 14 line by line, and a diazonium salt compound of a yellow thermal coloring layer is resolved at a yellow fixing light source 27 so as to dissipate a coloring capacity. Next, magenta images are recorded thermally on a magenta thermal coloring layer by returning the sheet 14 and are fixed with light at a magenta fixing light source 26. A drum 16 is rotated normally so as to record thermally on cyanogen thermal coloring layer omitting the light fixing and the sheet 14 is delivered on a tray 30.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a color thermosensitive recording method used in a thermal printer.

[Conventional technology]

There are two types of thermal printers: thermal printers and thermal transfer printers. Of these, thermal printers can record images directly onto thermal recording materials, so they do not generate waste such as transfer sheets, and their structure is It has the advantage of being simple. Because of these features, thermal printers tend to be widely used; for example, most facsimile machines incorporate monochrome thermal printers. Recently, a magenta thermosensitive coloring layer is formed on a support, as described, for example, in Japanese Patent Application Laid-Open No. 61-213169.

A color thermosensitive recording material has been proposed in which a cyan thermosensitive coloring layer and a yellow thermosensitive coloring layer are sequentially layered to enable full-color images to be directly thermally recorded.

Further, Japanese Patent Application Laid-Open No. 61-213169 describes a color thermal printer for recording color images on color thermal recording materials. This color furious printer is
A light source unit consisting of a light source and a three-color filter is arranged downstream of the thermal head. When recording heat, the drum equipped with color heat-sensitive recording material is rotated in the normal direction.
A yellow image is recorded on the yellow thermosensitive coloring layer using a thermal head, and the yellow thermosensitive coloring layer is optically fixed by irradiating the yellow image-recorded portion with light from a light source through a yellow filter. Next, the drum is reversed to once return the color thermosensitive recording material to the recording start position, and then a cyan image is recorded on the cyan thermosensitive recording layer with the thermal head while the drum is rotated forward. At the same time, light from a light source is irradiated through a cyan filter to the area where the cyan image is recorded, thereby optically fixing the cyan thermosensitive coloring layer. After the drum is reversed again to return the color thermosensitive recording material to its initial position, a magenta image is recorded on the magenta thermosensitive coloring layer by a thermal head while the drum is rotated in the normal direction, and then optically fixed using a magenta filter.

[Problem to be solved by the invention]

The aforementioned color thermal printer prints yellow and cyan images by moving the color thermal recording material back and forth two and a half times.

Since the magenta image is thermally recorded in a frame-sequential manner,
There is a problem that thermal recording takes time.

SUMMARY OF THE INVENTION An object of the present invention is to provide a color thermal recording method that allows color images to be thermally recorded in a short time.

[Means to solve the problem]

In order to achieve the above object, the present invention provides a first light source for optically fixing the third heat-sensitive recording layer and a second light source for optically fixing the second heat-sensitive recording layer. While moving the color thermosensitive recording material in the first direction, the thermal head recorded an image on the third thermosensitive coloring layer, and the first light source was turned on to pass through the thermal head. A portion of the color thermosensitive recording material is irradiated to optically fix the third thermosensitive coloring layer, and then, while moving the color thermosensitive recording material in a second direction opposite to the first direction, a second coloring layer is irradiated with a thermal head. At the same time as recording an image on the heat-sensitive coloring layer, the second light source is turned on to irradiate the part of the color heat-sensitive recording material that has passed through the thermal head to optically fix the second heat-sensitive coloring layer, and finally the color heat-sensitive recording material is recorded. An image is recorded on the first thermosensitive coloring layer by a thermal head while moving in a first direction.

[Effect]

In the present invention, images are recorded not only in the forwarding process of the color thermosensitive recording material but also in the returning process. Therefore, since a color image is recorded in half a round trip, it is possible to perform high-speed recording compared to the conventional color thermal recording method.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings.

A long color heat-sensitive recording material 11 is wound into a roll on the supply reel 10, pulled out by a pair of pull-out rollers 12, and cut into color heat-sensitive sheets 14 of a predetermined length by a cutter 13. This color heat-sensitive sheet 14 is guided by a guide member 15 so as to come into contact with the outer periphery of the drum 16 . This drum 16 extends in the direction of the paper and is rotated by a pulse motor 17. Further, a plurality of rollers 18 to 23 are arranged around the outer periphery of the drum 16 and rotate together with the drum 16, and the color thermosensitive recording sheet 14 is sandwiched between these rollers and conveyed. Note that the drum 16 is provided with a chucking mechanism to chuff the leading edge of the color thermosensitive recording sheet 14.
Alternatively, a large number of suction holes may be formed on the outer periphery of the drum 16, and the color thermosensitive recording sheet 14 may be vacuum-adsorbed.

A thermal head 25 in which a large number of heating elements are arranged in a line is arranged at the thermal recording position, and each heating element generates heat to a temperature corresponding to the color and density of the pixel to be recorded.

The peak wavelength is 36 on both sides of this thermal head 25.
a magenta fixing light source 26 that generates 5 nm ultraviolet light;
A constant yellow light source 27 that generates near ultraviolet light (blue-violet light) with a peak wavelength of 420 nm is arranged. Rod-shaped light sources are used as these fixing light sources 26 and 27, and extend in the axial direction of the drum 16. Further, the light sources 26 and 27 may use the same ultraviolet lamp, and may be combined with a bandpass filter to extract electromagnetic radiation in a specific wavelength range. Printed color thermal recording sheet 14
A separation pawl 28 is provided for discharging. The color thermosensitive recording sheet 14 separated by the separating claw 28 is
The paper is sent to a tray 30 via a pair of discharge rollers 29 .

The head control section 32 controls the amount of heat generated by the thermal head 25 in accordance with an image signal taken in from an image signal input section 33 such as a TV camera, a video player, or a scanner. The lamp control unit 34 causes the magenta fixing lamp 26 to emit light when thermally recording a magenta image, and causes the yellow fixing lamp 27 to emit light when thermally recording a yellow image. The controller 35 includes the head control section 32. Lamp control section 34. Cutter drive section 36. The drivers 37 and 38 are each controlled in sequence. This cutter drive unit 36 is the cutter 13
The driver 37 also controls a pulse motor 39 for rotating the pull-out roller 12.

FIG. 3 shows an example of a color thermosensitive recording material. On the support 40, a cyan thermosensitive coloring layer 41, a magenta thermosensitive coloring layer 42. Yellow thermosensitive coloring layer 43. Protective layer 44
are arranged in successive layers. Each of these thermosensitive coloring layers 41 to 4
3 is layered from the surface in the order of thermal recording, but
For example, when thermal recording is performed in the order of magenta, yellow, and cyan, the positions of the yellow thermosensitive coloring layer and the magenta thermosensitive coloring layer are swapped.

As the support 40, an opaque coated paper or a plastic film is used, and when an OHP sheet is created, a transparent plastic film is used.

The cyan thermosensitive coloring layer 41 contains an electron-donating dye precursor and an electron-accepting compound as main components, and develops cyan color when heated. As the magenta thermosensitive coloring layer 42,
It contains a diazonium salt compound with a maximum absorption wavelength of 360±20 nm and a coupler that develops a magenta color by thermally reacting with the diazonium salt compound. This magenta thermosensitive coloring layer 42 is
After thermally recording a magenta image with a thermal head, 36
When irradiated with ultraviolet light of 0±20 nm, the diazonium salt compound photodecomposes and loses its coloring ability. The yellow thermosensitive coloring layer 43 contains a diazonium salt compound having a maximum absorption wavelength of 420±20 nm and a coupler that thermally reacts with the diazonium salt compound to develop a yellow color. When this yellow thermosensitive color forming layer 43 is irradiated with near ultraviolet light of around 420 nm±20 nm, it is photofixed and loses its color forming ability.

This color thermosensitive recording material is described in detail in Japanese Patent Application No. 2-89384 filed by the present applicant on April 4, 1990.

FIG. 4 shows the characteristics of each of the thermosensitive coloring layers 41 to 43. Thermal energy on the horizontal axis represents the thermal energy generated by the heating element of the thermal head 25, with the yellow thermosensitive coloring layer 43 having the lowest thermal energy and the cyan thermosensitive coloring layer 41 having the highest thermal energy. The main reason for this difference in thermal energy is that the cyan thermosensitive coloring layer 41 is different from the yellow thermosensitive coloring layer 43. This is because heating must be performed via the magenta thermosensitive coloring layer 42.

FIG. 5 shows the absorption characteristics of the yellow thermosensitive coloring layer and the emission characteristics of the constant yellow light source.

As shown by the dotted line, the yellow thermosensitive coloring layer 43
It has light absorption in the range of 00 nm to 450 nm, and when irradiated with ultraviolet rays in this range, the diazonium salt compound is decomposed and photofixed. Therefore, the constant yellow light source 27 is
As shown by hatching 50, the emission energy of 420 nm is maximum.

FIG. 6 shows the absorption characteristics of the magenta thermosensitive coloring layer and the emission characteristics of the magenta fixing light source.

As shown by the dotted line, the magenta thermosensitive coloring layer 42 is
It has light absorption in the range of 00 nm to 400 nm. Therefore, the magenta fixing light source 26 has maximum emission energy at 365 nm, as indicated by hatching 51. Regarding these fixing light sources 26°27, patent application No. 2-
No. 89384.

Next, the operation of the apparatus shown in FIG. 1 will be explained with reference to FIG. 2. When the controller 35 is instructed to record heat,
The pulse motors 17 and 39 are started to rotate the drum 16 and the pull-out roller 12.

This pull-out roller 12 pulls out the color thermosensitive recording material 11 from the supply reel 10 and conveys it toward the drum 16. The direction of the leading end of the color thermosensitive photosensitive material 11 is changed by the guide member 15, and the direction of the leading end of the color thermosensitive photosensitive material 11 is changed by the rotating drum 1
6 and the roller 18, and moves together with the drum 16. When the color thermosensitive recording material 11 is pulled out for a certain length, the pulse motors 17 and 39 stop rotating, and immediately after that, the cutter 13 is operated by the cutter driving section 36 to cut the color thermosensitive recording sheet 14.

As shown in FIG. 2(A), after the cutter 13 is operated, the pulse motor 17 rotates at high speed, and the drum 16° rollers 18 to
23 is rotated to send the color thermosensitive recording sheet 14 to the heat recording position.

When the leading edge of the recording area of the color thermosensitive recording sheet 14 reaches the thermal recording position, thermal recording of the yellow image is started. First, the head control section 32 reads out the image signal for the first line of the yellow image from the image input section. This one-line image signal is converted into a drive signal in consideration of the coloring characteristics shown in FIG. 4. The drive signal for this one line is
It is sent to the thermal head 25 and supplied to the corresponding heating element, causing each heating element to generate heat to a temperature corresponding to the density to be recorded. As a result, the first line of the yellow image is thermally recorded on the color thermosensitive recording sheet 14. When the recording of the first line is completed, the pulse motor 17 and the drum 1
6! Rotate the line. According to the above-described procedure, the drive signal for the second line of the yellow image is sent to the thermal head 25, and the second line is thermally recorded on the color thermosensitive recording sheet 14. Thereafter, the yellow image is thermally recorded line by line in the same manner.

As shown in FIG. 2(B), when a yellow image is thermally recorded, the yellow constant light source 27 is turned on and generates near ultraviolet light of around 420 nm, and the portion of the color thermosensitive recording sheet 14 where the yellow image is thermally recorded. irradiate. This near ultraviolet light of 420 nm decomposes the diazonium salt compound contained in the yellow thermosensitive coloring layer 43 and causes the coloring ability to disappear.

After recording the yellow image, the pulse motor]7
Reverse the color thermosensitive recording sheet 14 and put it back. In the returning step of this color thermal recording sheet) 14, as shown in FIG.
As shown in C), the thermal head 25 thermally records the magenta image on the magenta thermosensitive coloring layer 42 line by line.

At the same time, the magenta thermosensitive color forming layer 42 is optically fixed by irradiating the area where the magenta image has been recorded with 365 nm ultraviolet rays generated from the magenta fixing light source 26. In addition,
When thermally recording this magenta image, as shown in FIG. 4, thermal energy is used within a range of approximately 40 to 70 mJ/mm'' and in accordance with the density to be recorded.

The thermal energy in this range is higher than the thermal energy required to record the yellow thermosensitive coloring layer 43, but since the yellow thermosensitive coloring layer 43 has already been optically fixed, it is unlikely that the yellow thermosensitive coloring layer 43 will color. do not have.

After recording the magenta image, as shown in FIG. 2(D),
The pulse motor 17 is rotated normally to rotate the drum 16 in the direction of the arrow. During this rotation, the thermal head 25 thermally records a cyan image on the cyan thermosensitive coloring layer 41 line by line. Note that the cyan thermosensitive coloring layer 41 does not develop color under normal storage conditions because the thermal energy required for thermosensitive coloring is approximately 80 mJ/mm" or more. Therefore, the cyan thermosensitive coloring layer 41 omits optical fixation.

Since the drum 16 continues to rotate even after recording the cyan image, as shown in FIG. The separating claw 28 separates the color thermosensitive recording sheet 14 from the leading end thereof, moves it 4 degrees toward the discharge roller 29, and discharges it onto the tray 30.

In the above embodiment, the color thermosensitive recording sheet is conveyed by the drum, but instead of this, a pair of upper and lower bolts may be used, and the color thermosensitive recording sheet may be conveyed by sandwiching the color thermosensitive recording sheet between them. You may use it in combination. Alternatively, a color thermosensitive recording sheet may be set on a slide table, and the slide table may be moved back and forth. Furthermore, a cassette containing color thermosensitive recording sheets may be used.

〔Effect of the invention〕

As described in detail above, according to the present invention, images are thermally recorded in both the forwarding process and the returning process of the color thermosensitive recording material, so thermal recording is performed in a shorter time than in conventional color thermal recording methods. It can be performed.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing an example of a color thermal printer implementing the method of the present invention. FIGS. 2(A) to 2(E) are explanatory diagrams showing the procedure of thermal recording of a color image. FIG. 3 is an explanatory diagram showing the layer structure of a color thermosensitive recording material. FIG. 4 is a graph showing the coloring characteristics of color thermosensitive recording materials. FIG. 5 is a graph showing the absorption characteristics of the yellow thermosensitive coloring layer and the spectral energy of a constant yellow light source. FIG. 6 is a graph showing the absorption characteristics of the magenta thermosensitive coloring layer and the spectral energy of the magenta fixing light source. Color drum thermal to rad magenta fixing light source yellow constant fixing light source. Figure (A) Figure (C) Figure (B) Figure (D)

Claims (1)

[Claims] (1) In a color thermosensitive recording method in which a color image is recorded by frame-sequential thermosensitive recording using a color thermosensitive recording material in which first to third thermosensitive coloring layers are layered on a support, the third thermosensitive recording layer A first light source for optically fixing the color thermosensitive recording material and a second light source for optically fixing the second thermosensitive recording layer are respectively disposed on both sides of the thermal head, and the color thermosensitive recording material is oriented in the first direction. While moving, the thermal head records an image on the third thermosensitive coloring layer, and the first
A light source is turned on to irradiate the part of the color heat-sensitive recording material that has passed through the thermal head to optically fix the third heat-sensitive coloring layer, and then the color heat-sensitive recording material is moved in a second direction opposite to the first direction. While moving, the thermal head records an image on the second thermosensitive coloring layer, and the second light source is turned on to illuminate the part of the color thermosensitive recording material that has passed through the thermal head to record the image on the second thermosensitive coloring layer. A color thermosensitive recording method, characterized in that the color thermosensitive recording material is optically fixed, and finally an image is recorded on the first thermosensitive coloring layer using a thermal head while moving the color thermosensitive recording material in a first direction.