JPS6056568A - Laser multicolor thermosensitive printer - Google Patents

Abstract

PURPOSE:To enable formation of the clear color of each color-forming group and high-speed recording without trouble by recording with a laser beam of wave length corresponding to an adsorptive wave length of an infrared ray absorbing material. CONSTITUTION:Laser beam emitted from later sources 1, 2 and 3 are modulated on and off respectively by acoustic optical modulators 4, 5 and 6. As for laser beam modulation, a printing pattern signal transmitted by a computer, etc. is decomposed into signals for modulating a laser beam which causes a respective prearranged color-forming group to form a color. Then each laser beam is modulated on and off. Following this procedure, said beam is conducted to a galvano mirror 10 and then is reflected on an F-theta mirror 11 according to a scan angle of mirror 10. Finally, the beam is projected into a corresponding spot position in a paper width of a multicolor recording material 12.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a laser multicolor thermal printer, and in particular to a laser multicolor thermal printer for a thermal recording medium configured to obtain a multicolor image by utilizing the energy of a plurality of infrared lights having different wavelengths. Regarding color printers.

Conventionally, heat-sensitive recording materials are well known, which utilize a coloring reaction between a coloring agent and a coloring agent that develops color when they come into contact with the coloring agent, and bring both substances into contact with each other using heat to obtain a colored image. There is.

Further, as a recording method for such a heat-sensitive recording material, a method is generally used in which recording is performed by closely scanning a recording layer with a recording head (thermal head) having a heating element. However, in such a system, wear of the head, adhesion of residue to the head surface, and so-called sticking trouble in which the head and the recording layer stick together are likely to occur. Furthermore, since the recording speed depends on the heat dissipation time of the thermal head, high-speed recording is difficult, and there is also a limit to the resolution of colored images due to thermal diffusion. Therefore, instead of such a thermal head contact scanning method, various techniques have been proposed for non-contact recording by scanning with high energy density light such as a laser beam.

On the other hand, there is an increasing demand for recording media that can record in multiple colors.For example, multiple coloring agents and coloring agents that are combined to have different coloring temperatures are formed as a mixed layer or a laminated layer. Thermosensitive recording materials are being considered.

However, in a recording medium that performs multicolor recording using such differences in coloring temperature, regardless of the recording means such as a thermal head or a laser beam, it is necessary to use a low temperature when coloring a high temperature coloring part. There are 114 points in which the coloring part is also colored, and the two colors are mixed, making it impossible to obtain a recorded image with a bright difference in tone.

Therefore, Japanese Patent Application No. 57-199424 discloses that in a multicolor recording medium having a plurality of coloring systems that produce different colors, the coloring system has a method for producing the infrared light used to produce the color. Each color is developed through the intervention of a substance (hereinafter referred to as an infrared absorbing substance) that exhibits absorption but does not substantially absorb infrared light having a different wavelength that is used to generate other colors. A multicolor recording medium configured as follows has been proposed.

The present inventors have developed various printers for recording media configured to obtain multicolor images using a plurality of infrared lights of different wavelengths as described above, especially laser multicolor thermal printers capable of high-speed recording. As a result of repeated studies, we have completed the present invention.

The present invention is a laser multicolor thermal printer characterized by having a plurality of laser light sources that oscillate infrared light of different wavelengths.

The laser light source used in the laser multicolor thermal printer of the present invention is not particularly limited as long as it emits infrared light having a wavelength in the range of about 0.8 to 30 μm. Specifically, solid-state lasers such as YAG lasers (1,06 μm) and Ne lasers (1,15, c
rm, 3.3! llum), Co laser (5 μm
), CO2 laser (9.2-9.7 pm, 10.
gas laser such as Cd5nPz
(1,01, crm), Garb (1,53pm
), Cd3P2 (2,12,um), InAs(
3,1 μm), Te (3,7 μm), (Hg, Cd
) Te (3,9-4.1 μm), Pb5 (4,3,
crm), InSb (5,2pm), PbTe
(6,5pm), Pb5e (8,5,cam)
, InAs+-zPz (0.9-3 μm), In
1-zGaz As (0.9-3 μm), P
bS+-xsex (3-8 μm), Pb1-zsn
χTo (7-30 IIm), pb, -.

Examples include semiconductor lasers using semiconductors such as Snχ5e (8 to 30 μm). Note that the CO2 gas laser has approximately 200 oscillation lines in the wavelength range of 9 to 11 μm; for example, by grating operation, 9.2 μm,
Laser beams with different wavelengths such as 9.6 μm and 10.6 pm can be extracted. In addition, semiconductor lasers include those with a fixed oscillation wavelength and those with a variable wavelength. Among the above, In71st-zpχ, In1
−． 4Gaχ ^sS PbS t1Sex, Pb1-
A semiconductor laser having a composition such as zsnχ Tes Pb1 (SnχSe) can oscillate infrared light having various wavelengths within the above range by changing its composition, applied current, cooling temperature, etc.

In the present invention, from among the laser light sources having various oscillation wavelengths as described above, each one is selected according to the absorption wavelength of the infrared light absorbing substance contained in each of the plurality of coloring systems constituting the recording layer of the multicolor recording medium. Laser light sources with corresponding oscillation wavelengths are used in appropriate combinations. Although it is possible to combine solid-state lasers or gas lasers with semiconductor lasers, solid-state lasers, gas lasers, and semiconductor lasers each have the following features, and in order to take advantage of their respective advantages, it is necessary to combine solid-state lasers or gas lasers with semiconductor lasers. Alternatively, it is desirable to configure the laser light source within a group of gas lasers or only with semiconductor lasers. That is, while solid-state lasers and gas lasers can provide relatively high-output infrared light compared to semiconductor lasers, they may require optical systems such as a modulator and an optical scanning system to turn the laser beam on and off. many. On the other hand, semiconductor lasers have extremely small laser elements, do not require a modulator or optical system, and can perform output modulation at the same time as switching by changing the applied current, which together make it possible to create a compact printer. At present, it is difficult to obtain relatively high-output infrared light.

As mentioned above, when using a solid laser or a gas laser as a laser light source, an optical scanning system is essential, but if such an optical system is provided for each of the plurality of laser light sources, the entire printer device will become larger. However, it has been found that it is extremely difficult to prevent the misalignment of printed characters (dots).Therefore, in the present invention, one set of optical scanning systems is used in common to solve this problem.

An example of the laser multicolor thermal printer of the present invention using a plurality of laser light sources selected from the group of solid-state lasers and gas lasers will be described with reference to FIG. 1. In the example shown in FIG. 1, 3' CO2 gas lasers having different oscillation wavelengths were used as laser light sources.

Laser beams emitted from laser light sources (1), (2), and (3) that oscillate infrared light with wavelengths of 9.2 μm, 9.6 μm, and 10.6 μm are transmitted to an acousto-optic modulator (4),
(5) and (6) respectively cause ON-OFF switching. Such modulation of the laser beam is performed by converting a printing pattern signal from a computer (not shown) into a decoder (
14) The signal is decomposed into signals for modulating a laser beam for coloring a predetermined coloring system, and a modulator is driven by these decomposed signals to perform ON-OFF modulation of each laser beam.

Then, the laser beam modulated by the modulator (4) is
It is reflected by the reflective mirror (7), and is reflected by the guichroic mirror (
After passing through 8) and (9), galvanometer mirror (10)
guided by. Further, the laser beam modulated by the modulator (5) is reflected by the dichroic mirror (8), passes through the dichroic mirror (9), and then enters the galvanic mirror (10). On the other hand, the laser beam from the modulator (6) is reflected by the gicroic mirror (9) and guided to the carbanomirror (10). In addition,
Reflection mirror (7) and Gicroic mirror (8), (
9) is arranged so that the optical axes of the reflected light from the reflecting mirror (7), the reflected light from the glaucroic mirror (8), and the reflected light from the guicroic mirror (9) coincide with each other. .

The galvanomirror (10) is a reflecting mirror that is angularly displaced depending on the current supplied to the solenoid, and the F
Together with the θ main mirror 11), it forms an optical scanning system. The laser beam incident on the galvano mirror (10) is applied to the I7θ mirror (4) according to the scanning angle of the galvano mirror (10).
11), further reflected by the Fθ main mirror 11), and is incident on a corresponding spot position within the paper width of the multicolor recording medium (12).

For multicolor heat-sensitive printers that require the optical system described above, it is necessary to consider the reflectance and transmittance of the laser beam in reflective mirrors, dichroic mirrors, etc., and add a circuit to correct this (desirably). In other words, in FIG. 1, for example, the beam from the laser light source (1) passes through the gicroic mirrors (8) and (9), so the color density on the recording medium decreases due to loss due to absorption. ). (The number of the modulator drive signal from the decoder (14) is - the disturbance intensity modulation circuit (15), (16)
After intensity modulation by

In addition, instead of such an intensity modulation circuit, there is a method in which laser light sources with different outputs are used in advance, and the sensitivity of each color system of the multicolor recording medium is adjusted, etc., thereby controlling the color density. It is also possible to equalize the

Using the laser multicolor heat-sensitive inkjet printer constructed in this way, zinc silicate (absorption wavelength: io,
A blue coloring thermal recording coating liquid containing ultrafine particulate talc (absorption wavelength: 9.6μI), a red coloring thermal recording coating liquid containing ultrafine particulate talc (absorption wavelength: 9.6μI), and barium sulfate (absorption wavelength: 9.6μI). 2 μm)).When recording was carried out on a multicolor recording paper (12) obtained by successively overcoating a recording coating liquid onto high-quality paper while being fed in steps by a recording paper feeding mechanism (18), The modulator (4) outputs O based on the print pattern signal.
Yellow by the laser beam modulator (5)
The red color is the beam turned on by the modulator (6), and the red color is turned on by the modulator (6).
The beam produced a vivid blue color. In addition, in the multicolor thermal printer of the present invention, each dot is not only irradiated with a single laser beam to develop a corresponding monochrome color, but also irradiated with laser beams from laser light sources (1) and (3) simultaneously, for example. It is also possible to record mixed colors using multiple beams, such as a green color.

In the above laser multicolor printer, an acousto-optic modulator (A1
Although an electro-optic modulator (E10 transformer) made of CdTe single crystal was used, an electro-optic modulator (E10 transformer) made of CdTe single crystal may also be used. Furthermore, a polygon mirror (rotating polygon mirror) can be used instead of the Garno mirror. In addition, the dichroic mirror used here is Ge, CaP2, CdTe.
A multi-N vapor deposited film is provided on the surface of an infrared light transmitting material such as Zn5e, GaAs, St, etc. to form a semi-transparent mirror.

As mentioned above, semiconductor lasers have extremely small laser elements and can be driven directly by applied current without the need for an external modulator. Therefore, laser elements can be arranged on the recording surface according to the number of pixels (dots). By driving these elements at the same time, a large number of pixels can be printed at the same time, and high-speed recording is possible even if the output of each semiconductor sheet 11' element is relatively small.

Below, semiconductor laser 11! is used as a laser light source. A multicolor thermal printer using - will be described, but one type of method can be adopted depending on the arrangement of semiconductor lasers used.

The first method, as shown in FIG. 2, is a semiconductor laser play array (21) in which semiconductor laser elements having the same oscillation wavelength are arranged in a play shape along the transverse direction of the recording surface.
An array (22) in which semiconductor laser elements having an oscillation wavelength different from those of the array (21) are similarly arranged, and semiconductor laser elements having an oscillation wavelength different from those of the array (21) and (22). The constructed array (23
), a group of arrayed columns each having a different oscillation wavelength is used as a laser light source, and is arranged on a recording medium in a non-contact manner.

In this example, a print pattern signal from a computer or the like is decomposed into signals for each array column and each semiconductor laser element constituting each array column in the demodulation and semiconductor laser drive circuit (26). Serves as switching and output regulation signal.

In the second method, as shown in FIG. 3, a semiconductor laser array (28) in which wavelength tunable semiconductor laser elements are arranged in an array along the transverse direction of the recording surface is used as a laser light source, and this is used as a laser light source. This is a method of placing the device in a non-contact manner.

In this method, after the print pattern signal is demodulated and decomposed into each laser element by the 44-body laser drive circuit (31), the signal is configured to function as a switch, oscillation wavelength regulation, and output regulation signal for each element. ing.

In addition, as for the wavelength tunable semiconductor laser device, as mentioned above,
The oscillation wavelength can be changed by changing any one of the semiconductor composition, applied current, and cooling temperature. However, within a certain current range, the output can be changed without a large change in the oscillation wavelength, so intensity modulation is possible by varying the applied current within this range. Therefore, it can also be used as a semiconductor laser device of the first method described in Section 2.

Moreover, using these semiconductor laser elements, 1. In a multi-color thermal printer, a plurality of rows of semiconductor laser arrays using the first method G described above are used, and a plurality of rows of wavelength tunable semiconductor laser arrays IJ of the second method are used. It is also possible to further improve high-speed recording suitability.

The thus obtained laser multicolor thermal printer of the present invention performs recording with a laser beam of a wavelength corresponding to the absorption wavelength of the infrared light absorbing substance contained in each coloring system in the recording medium. are vividly colored,
Furthermore, high-speed recording is possible without causing head wear or sticking problems.

[Brief explanation of the drawing]

Figure 1 is a configuration diagram of a laser multicolor thermal blink using a CO2 gas laser with three different oscillation wavelengths as a laser light source, and Figure 2 shows three types of semiconductor laser arrays each having a different oscillation wavelength. FIG. 3 is a block diagram of a printer that uses a wavelength-tunable semiconductor laser array as a laser light source. (1) (2) (3): COZ gas laser oscillation tube. (4)(5)(6): Acousto-optic modulator. (7): Reflection mirror. (8) (9): Dichroic mirror. (10) n-galvano mirror 5 (11): Fθ main mirror (12): multicolor thermal recording paper. (13): Recording paper roll, (14): Decoder. (15) (16) (17): Intensity modulation circuit. (18): Recording paper feeding mechanism. (19) Varnish chipping motor. (20): Motor driver. (21) (22) (23): Semiconductor laser array. (24): Multicolor thermal recording paper, (25): Recording paper roll. (26): Demodulation and semiconductor laser drive circuit. (27) Two recording paper feeding mechanisms. (28): Wavelength tunable semiconductor laser array. (29): Multicolor thermosensitive recording paper, (30): Recording paper roll. (31): Demodulation and semiconductor laser drive circuit. (32): Recording paper feeding mechanism. Patent applicant Kanzaki Paper Co., Ltd. Figure 1 Figure 2

Claims (1)

[Claims] (1) A laser multicolor thermal printer characterized by having a plurality of laser light sources that oscillate infrared light of different wavelengths. (21 (al) a plurality of laser light sources selected from the group of solid-state lasers and gas lasers, (b) a plurality of modulators for turning ON-OFF the laser beams emitted from each laser light source, (after C1 modulation) A reflecting mirror and a plurality of dichroic mirrors for guiding each laser beam into one optical scanning system are formed, and each dichroic ink mirror is reflected from the reflective optical axis. a set of optical scanning systems for scanning the laser beam from the d1 reflecting mirror group in the transverse direction of a predetermined recording surface and focusing it on the surface. Claim No. fi
The printer described in item 1. (3) Semiconductor laser arrays in which semiconductor laser elements emitting laser beams of the same wavelength are arranged in an array along the transverse direction of the recording surface are arranged so that the oscillation wavelength is different between each array. Claim number (1) with multiple columns
) Printer listed in section. (4) The printer according to claim (1), further comprising at least one semiconductor laser array in which wavelength tunable semiconductor laser elements are arranged in an array along the transverse direction of the recording surface.