JPH0752420A - Method and device for thermal recording - Google Patents

Abstract

PURPOSE:To form an image or the like of high quality and simplify the constitution by sensing easily end precisely the temperature of a heat sensitive recording material itself before or after the recording of image or the like. CONSTITUTION:A method and a device for thermal recording comrises a recording means 12 for heating a heat sensitive recording material S up to the given coloring temperature and recording, a preheating means 14 for preheating the heat sensitive recording material S up to the temperature lower than the coloring temperature, and a density sensing means 18 provided in the preheated heat sensitive recording material S and sensing the density of a site 16 to be inspected which is colored preliminarily, and the preheating means 14 is controlled by a control section 20 based on the sensed density, and the heat sensitive recording material S is preheated precisely up to the given temperature lower than the coloring temperature.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal recording method and apparatus for recording an image or the like by applying heat energy to a thermal recording material.

[0002]

2. Description of the Related Art Thermal recording apparatuses for imparting thermal energy to a thermal recording material to record an image or the like have been widely used. For example, a laser capable of high-speed recording has appeared by using a laser as a heat source (Japanese Patent Laid-Open No. 50-23617).
JP-A-58-94494 and JP-A-62-7798.
3 and JP-A-62-78964).

The present applicant has applied a color developing agent, a color developing agent and a light absorbing dye on a support as a heat sensitive recording material which is applied to such a thermal recording apparatus and is capable of recording a good image with high quality. A material that develops and develops a color at a concentration according to the added heat energy has been developed and applied for a patent (Japanese Patent Application No. 3-6).
No. 2684, Japanese Patent Application No. 3-187494).

In this heat-sensitive recording material, microcapsules containing at least a basic dye precursor, a color developer and a light-absorbing dye are dissolved in an organic solvent which is hardly soluble or insoluble in water and then emulsified and dispersed. The heat-sensitive layer is formed by applying a coating liquid containing the emulsion.

In order to maintain a stable storage state, such a heat-sensitive recording material is constructed so as not to develop color with low heat energy. Therefore, a considerable amount of heat energy is required to obtain the desired color development state. As a result, the dynamic range is narrowed by the threshold value of heat energy until color development, and it is difficult to obtain a high gradation image. In addition, the burden on the device side for color development becomes considerably large.

Therefore, the present applicant proposes a thermal recording device configured to preheat the thermal recording material to a predetermined temperature lower than the coloring temperature and then irradiate the thermal recording material with a laser beam to develop the color. (Japanese Patent Application No. 5-3888)
(See No. 8). As a result, it is possible to obtain an image with high gradation and high precision easily and with high precision, and to reduce the burden on the heating means.

On the other hand, it is known that the image density of a heat-sensitive recording material on which an image is recorded by applying a predetermined amount of heat energy increases with time when stored at room temperature. Therefore, there is a problem that the image density is different immediately after recording and after a predetermined time has elapsed. Therefore, the present applicant has proposed a thermal recording method and apparatus for irradiating the thermal recording material with a laser beam to record a visible image, and then heating the thermal recording material again at a temperature lower than the coloring temperature (special feature). See Japanese Patent Application No. 5-205965). This has the advantage that the color development reaction is promoted immediately after recording and an image with stable density is obtained.

[0008]

In this case, in order to form a high quality image on the heat-sensitive recording material, the heat-sensitive recording material is surely preheated to a predetermined temperature, while the heat-sensitive recording material after image recording is colored. It is necessary to ensure heating to a temperature below the temperature. Therefore, it is desired to accurately detect the temperature of the preheated heat-sensitive recording material itself or the temperature of the heat-sensitive recording material itself heated after image recording, but as a detection device of this kind, for example, a radiation thermometer or the like. There is the problem of having to use such complex and expensive equipment.

The present invention is to solve this kind of problem, and easily and accurately detects the temperature of the heat-sensitive recording material itself before or after recording an image or the like to form a high-quality image or the like. It is an object of the present invention to provide a thermal recording method and a thermal recording method capable of simplifying the configuration.

[0010]

In order to achieve the above-mentioned object, the present invention provides a thermosensitive recording material containing a coloring material which develops a color upon application of heat energy and then its equilibrium moves at a temperature, via a recording means. A thermal recording method in which recording is performed by heating to a predetermined color development temperature, the process of pre-coloring a portion to be inspected of the heat-sensitive recording material, and the heat-sensitive recording material being colored by preheating means. A step of preheating to a temperature lower than a temperature, a step of detecting the concentration of the color-developed and preheated inspected portion, and a predetermined heat energy is applied by the recording means to the thermosensitive recording material in which the concentration is detected. And a process of recording.

Further, according to the present invention, thermal recording is carried out by heating a heat-sensitive recording material containing a color-forming material whose equilibrium moves at a temperature after coloring by applying heat energy, to a predetermined color-forming temperature via a recording means for recording. A method of applying predetermined heat energy to the heat-sensitive recording material by the recording means to perform recording, and recording the recorded heat-sensitive recording material through a heating means to a temperature lower than a coloring temperature of the heat-sensitive recording material. The step of heating to the temperature of, and the step of detecting the concentration of the inspected site which is provided in the heated thermosensitive recording material and is previously colored,
It is characterized by including.

Further, according to the present invention, there is provided recording means for recording by recording a heat-sensitive recording material containing a color-forming material whose equilibrium moves at a temperature after coloring by applying heat energy, to record by heating to a predetermined color-forming temperature. Preheating means for preheating the material to a temperature lower than the coloring temperature before the recording, density detecting means provided in the preheated heat-sensitive recording material and for detecting the density of the pre-colored portion to be inspected, and the detected And a control unit that controls the preheating means based on the concentration.

Furthermore, the present invention further comprises a recording means for heating a heat-sensitive recording material containing a color-forming material whose equilibrium moves at a temperature after coloring by applying heat energy to a predetermined color-forming temperature for recording, and the heat-sensitive recording material. Heating means for heating the recording material to a temperature lower than the coloring temperature after the recording, and density detecting means for detecting the density of the portion to be inspected, which is provided on the heated recording material after completion of the recording and which is colored in advance. And a control unit that controls the heating unit based on the detected concentration.

[0014]

In the heat recording method and apparatus according to the present invention, the color forming material contained in the heat sensitive recording material is such that the equilibrium of the color moving material is moved by the temperature after color development, and the density of the color-developed inspection site is detected. The temperature of the thermosensitive recording material itself can be detected corresponding to this concentration. Therefore, it is possible to easily and accurately detect the temperature of the heat-sensitive recording material after preheating and the temperature of the heat-sensitive recording material heated below the color development temperature after recording only by using the density detecting means. Therefore, by controlling the preheating means and the heating means based on the detected temperature, the heat-sensitive recording material can be surely preheated or heated to a desired temperature.

[0015]

The thermal recording method and apparatus according to the present invention will be described in detail below with reference to the accompanying drawings. In the following examples, the recording means is controlled to perform multi-gradation recording on the heat-sensitive recording material.

In FIG. 1, reference numeral 10 indicates a thermal recording apparatus according to the first embodiment. This thermal recording device 10
The thermal recording material S, which is sub-scanned and conveyed in the direction of arrow B, is scanned in the direction of arrow A by the laser beam L to record an image or the like. The thermal recording material S is heated to a predetermined color development temperature for recording. And a preheating means 14 for preheating the heat-sensitive recording material S to a temperature lower than the coloring temperature.
A density detecting means 18 provided on the preheated thermosensitive recording material S and detecting the density of the inspected portion 16 which has been colored in advance; and a control section for controlling the preheating means 14 based on the detected density. (Control means) 20.

The heat-sensitive recording material S comprises a transparent support 22 and a heat-sensitive layer 24 formed on the transparent support 22. The heat-sensitive layer 24 contains a combination of a microcapsule containing a basic dye precursor which is a leuco dye and a color developer, and a light-absorbing dye which absorbs the laser beam L and converts it into heat energy. Composed.

The basic dye precursor has a property of developing a color by donating an electron or accepting a proton such as an acid, and is generally colorless and has a lactone, a lactam, a sultone, a spiropyran, an ester, A compound having a partial skeleton such as an amide, which is opened or cleaved by contact with a color developer, is used.

Examples of developers for leuco dyes include phenol compounds, sulfur-containing phenol compounds, carboxylic acid compounds, sulfone compounds, urea compounds or thiourea compounds.

The recording means 12 includes a laser diode 26 for outputting a laser beam L, a collimator lens 28 for collimating the laser beam L, a cylindrical lens 30, a reflecting mirror 32, and a polygon for deflecting the laser beam L. The mirror 34, the fθ lens 36, and the cylindrical lens 30 cooperate with each other to form the polygon mirror 34.
And a cylindrical mirror 38 that corrects the face tilt of the. The laser diode 26 is controlled by the control unit 20 via the driver 40.

The preheating means 14 is provided with a casing 42 which is arranged at a predetermined distance from the heat-sensitive recording material S, and high frequency induction coils 46a and 46b are housed in the casing 42 with a pair of partition plates 44a and 44b interposed therebetween. To be done. The high frequency induction coil 46a is arranged upstream of the irradiation position of the laser beam L in the direction of the arrow B, and the high frequency induction coil 46b is arranged corresponding to the irradiation position of the laser beam L. 46b is controlled by the control unit 20.

The casing 42 has partition plates 44a, 4
Correspondingly, a hole 48 is formed between the holes 4b.
A light emitting section 50 which constitutes the concentration detecting means 18 is disposed above, and a light intensity detector 52 is provided between the partition plates 44a and 44b so as to face the light emitting section 50. The light emitting unit 50 is, for example, a laser diode with a collimator, the light intensity detector 52 is, for example, a photodiode, and the light emitting unit 50 and the light intensity detector 52 are connected to the control unit 20.

Next, the operation of the thermal recording apparatus 10 according to the first embodiment constructed as described above will be described.

The thermosensitive recording material S is sub-scanned and conveyed in the direction of arrow B under the action of the control section 20 through a conveying mechanism (not shown). Then, the heat-sensitive recording material S is heated to a temperature lower than the coloring temperature via the high frequency induction coils 46a and 46b forming the preheating means 14. As a result, the heat-sensitive recording material S is preheated to a temperature immediately before color development.

At this time, in the density detecting means 18, the light emitting section 5
The detection light L0 is derived from 0 toward the light intensity detector 52, and the detection light L0 passes through the inspected portion 16 that has been colored and preheated in advance, and the light intensity detector 52.
The light is received by the light source, and the color density of the portion to be inspected 16 is detected.

In this case, the color density of the portion to be inspected 16 is
As shown in FIG. 3, the equilibrium state of b to c is maintained, and the concentration moves along the b to c as the temperature T changes. Therefore, when the color density of the inspected portion 16 is detected, the temperature of the heat-sensitive recording material S itself is easily and accurately detected, and the high frequency of the preheating means 14 via the controller 20 is detected based on this color density. Induction coil 46a, 46b
Is controlled. Further, the output of the laser diode 26 which constitutes the recording means 12 can be controlled.

On the other hand, when the thermal recording material S reaches the recording position, the control section 20 drives the laser diode 26 via the driver 40. The laser diode 26 outputs the laser beam L modulated according to the gradation of the image recorded on the thermosensitive recording material S. The laser beam L is collimated by the collimator lens 28, and then guided to the polygon mirror 34 via the cylindrical lens 30 and the reflection mirror 32. The polygon mirror 34 rotates at a high speed, and the laser beam L reflected by its reflection surface is guided to the thermosensitive recording material S via the fθ lens 36 and the cylindrical mirror 38, and is sub-scanned and conveyed in the direction of arrow B. The heat-sensitive recording material S which is in the main scanning direction is scanned in the direction of arrow A. At that time, the heat-sensitive layer 24 of the heat-sensitive recording material S
A predetermined thermal energy corresponding to the color development temperature is applied to the recording medium by recording a gradation image.

As described above, in the first embodiment, the portion 16 to be inspected of the thermosensitive recording material S is colored in advance and preheated by the preheating means 14 to detect its concentration.
The temperature of the thermal recording material S itself can be detected.
Therefore, it becomes possible to reliably detect whether or not the thermal recording material S is accurately preheated to a predetermined temperature with a simple configuration, and a complicated and expensive detection device such as a radiation thermometer is unnecessary. There is an effect that can be. As a result, the preheating means 14 is controlled based on the detected temperature information of the thermal recording material S, and the thermal recording material S can always be accurately preheated to a predetermined temperature.

The preheating means 14 includes high frequency induction coils 46a and 46b. Instead of the high frequency induction coils 46a and 46b, a non-contact type preheating source such as a preheating light source, an infrared heater or a warm air heater is used. Alternatively, a contact type preheat source such as a heat roller may be used.

Next, the thermal recording apparatus 60 according to the second embodiment.
Will be described with reference to FIG.

The thermal recording device 60 is provided with a preheating means 62, a heating means 64 for heating the thermal recording material S to a temperature lower than the color development temperature after recording, and the heated thermal recording material S after the recording is completed. And a control unit (control means) 67 for controlling the heating means 64 based on the detected density.

The preheating means 62 comprises a casing 68 and a high frequency induction coil 70, and the heating means 64 and the concentration detecting means 66 are respectively the preheating means 14 according to the first embodiment.
The density detecting means 18 has the same structure as that of the density detecting means 18, and the same components are designated by the same reference numerals and detailed description thereof will be omitted.

In the thermal recording apparatus 60 thus constructed, the thermal recording material S conveyed in the direction of the arrow B is preheated to a temperature lower than the color development temperature through the preheating means 62 and is irradiated with the laser beam L. Then, a predetermined image is recorded by being colored. Then, the portion of the thermosensitive recording material S after the image recording is heated again to a temperature lower than the coloring temperature by the heating means 64. Therefore, it is possible to complete the color development reaction in a short time, and to obtain an image with a stable density for a long period of time without subsequent change with time.

When the heat-sensitive recording material S is heated by the heating means 64, the density of a portion to be inspected (not shown) of the heat-sensitive recording material S is detected by the density detecting means 66 provided corresponding to the heating means 64. Is detected. This inspected part is a recording device (recording device 1 of the thermal recording device 10) provided in advance in the recording device or the thermal recording device 60 (not shown).
(Corresponding to 2), a predetermined heat energy is applied to develop color, and the temperature of the thermal recording material S itself is detected by detecting the density of the inspected portion.

Therefore, the temperature of the heat-sensitive recording material S heated after recording can be detected easily and accurately with a simple structure, and if the heating means 64 is controlled based on the detection result, the heat-sensitive recording can be performed. The material S can be always heated to a predetermined temperature lower than the coloring temperature with high accuracy, and the effect of improving the stability of the image density can be obtained.

[0036]

According to the thermal recording method and apparatus of the present invention, the following effects can be obtained.

The coloring material contained in the heat-sensitive recording material is
Since the equilibrium moves with temperature after color development, the temperature of the thermosensitive recording material itself can be detected by detecting the density of the inspected site that has developed color. Therefore, it is possible to easily and accurately detect the temperature of the heat-sensitive recording material after preheating and the temperature of the heat-sensitive recording material heated below the coloring temperature after recording only by using the density detecting means. Therefore, by controlling the preheating means and the heating means based on the detected temperature, the heat-sensitive recording material can be surely preheated or heated to a desired temperature. As a result, the heat-sensitive recording material can be controlled to a desired preheating state with high accuracy with a simple structure, and a high-quality recorded image can be easily and efficiently obtained. Further, the heat-sensitive recording material after recording can be heated to a desired temperature lower than the color development temperature, and the stability of image density can be improved at once.

[Brief description of drawings]

FIG. 1 is a perspective view illustrating a configuration of a thermal recording apparatus according to a first embodiment of the present invention.

FIG. 2 is a partial front view of the thermal recording apparatus according to the first embodiment.

FIG. 3 is a diagram illustrating a relationship between equilibrium and temperature of a heat-sensitive layer constituting a heat-sensitive recording material.

FIG. 4 is a partial front view of the thermal recording apparatus according to the second embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Thermal recording device 12 ... Recording means 14 ... Preheating means 16 ... Inspected part 18 ... Concentration detection means 20 ... Control part 22 ... Transparent support 24 ... Heat sensitive layer 46a, 46b ... High frequency induction coil 50 ... Light emitting part 52 ... Light Intensity detector 60 ... Thermal recording device 62 ... Preheating means 64 ... Heating means 66 ... Concentration detection means 67 ... Control section S ... Thermal recording material

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location B41J 3/20 116

Claims (4)

[Claims] 1. A thermal recording method for recording by heating a thermosensitive recording material containing a color-forming material whose equilibrium moves at a temperature after being colored by application of heat energy, to a predetermined color-forming temperature via a recording means. A step of pre-coloring a portion to be inspected of the thermosensitive recording material, a step of preheating the thermosensitive recording material to a temperature lower than a color development temperature of the thermosensitive recording material via a preheating means, and the color-developed and preheated A thermal recording method comprising: a step of detecting the density of a portion to be inspected; and a step of applying predetermined thermal energy to the thermal recording material having the detected density by the recording means to perform recording. . 2. A thermal recording method for recording by heating a heat-sensitive recording material containing a color-forming material whose equilibrium moves at a temperature after being colored by application of heat energy, to a predetermined color-forming temperature through a recording means. A step of performing recording by applying predetermined heat energy to the heat-sensitive recording material by the recording means, and heating the recorded heat-sensitive recording material to a temperature lower than a coloring temperature of the heat-sensitive recording material via a heating means. And a step of detecting the density of the inspected portion which is provided in the heated thermosensitive recording material and which is colored in advance, and the thermal recording method. 3. A recording means for recording by recording a heat-sensitive recording material containing a color-forming material whose equilibrium moves at a temperature after color development by applying heat energy, to record the heat-sensitive recording material, Preheating means for preheating to a temperature lower than the coloring temperature before recording, density detecting means provided in the preheated thermosensitive recording material and for detecting the density of the pre-colored portion to be inspected, based on the detected density And a control unit for controlling the preheating means. 4. A recording means for heating a heat-sensitive recording material containing a color-forming material whose equilibrium moves at a temperature after coloring by applying heat energy to a predetermined color-forming temperature to perform recording, and the heat-sensitive recording material, Heating means for heating to a temperature lower than the color development temperature after recording, density detection means for detecting the density of the inspected part which is provided in the heated recording material after completion of recording and which has been colored in advance, and the detected A thermal recording device comprising: a control unit that controls the heating unit based on the concentration.