JPH11138997A - Image recording medium and method for recording image - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce in size an apparatus by forming first and second recording layers reversibly changing in color erasing and color developing states according to a difference of heating energy on a base material, and partly duplicating a heating energy for color developing the second layer and a heating energy for color erasing the first layer, thereby enhancing a falsification preventing effect of an image. SOLUTION: A first reversible thermal recording layer 3, a second reversible thermal recording layer 4 and a protective layer 5 are sequentially laminated and formed on a surface of a plate-like base material 2. The layers 3, 4 contain a dye agent and a color developing and reducing agent and change in color developing state and erasing state according to a difference of applied heating energies. The energy is larger in the case of color developing than that in the case of color erasing the layer 4. At least parts of the energy for color developing the layer 4 and the energy for color erasing the layer 3 are duplicated. And, the energy for color developing the layer 3 is constituted to be larger than that for color erasing it. Thus, recording and heating the first and second recording layers are selectively and simultaneously conducted in response to a recording image.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image recording medium capable of recording and rewriting an image (visible image), and
The present invention relates to an image recording method for recording and erasing an image on the image recording medium, and more particularly to an image recording medium and an image recording method having good image falsification prevention characteristics.

[0002]

2. Description of the Related Art Hitherto, for example, as an image recording medium capable of rewriting recording of a visible image, a recording material capable of reversibly changing to both a transparent state and a white turbid state by a heating temperature has been proposed (for example, see Japanese Patent Application Laid-Open No. H11-157556). See Japanese Unexamined Patent Publication No. 55-154198). Further, a recording material using a leuco dye, which exhibits two states of color development and decolorization, depending on the difference in applied heating energy, has been published (for example, Japan Hardcopy 9).
0, NIP-2, p147 (1990)).

A recording material that changes between a transparent state and a cloudy state and a recording material that changes into two states of coloring and decoloring due to a difference in applied heating energy is recorded by a thermal head.
Since the image recording apparatus can be erased, the image recording apparatus can be downsized, and has been put to practical use in so-called point cards. But,
Since recording and erasing can be easily performed by the thermal head, there is a risk that the image is tampered with.

For this reason, recently, various image recording media and image recording methods for preventing image falsification have been proposed. For example, JP-A-6-92018 discloses an irreversible thermosensitive recording material layer below a reversible thermosensitive recording material layer.
When an attempt was made to erase the portion recorded in the reversible thermosensitive recording material layer with a hot stamp, the reversible thermosensitive recording material layer could be erased, but heat was transferred to the irreversible thermosensitive recording material layer, and the irreversible thermal recording material layer was erased. The heat recording material layer develops color,
It is clear that they have been tampered with. But,
In this method, if recording and erasing are performed by a thermal head, there is a disadvantage that an image is easily falsified.

[0005] Also, JP-A-7-314899 discloses that
A light-to-heat conversion layer and a second reversible thermosensitive recording layer are provided below the first reversible thermosensitive recording layer. The first reversible thermosensitive recording layer is rewritten by a thermal head, and the first reversible thermosensitive recording layer is rewritten by a laser beam. The thermal recording layer and the second reversible thermosensitive recording layer are simultaneously rewritten, and important information to be prevented from being falsified is simultaneously recorded on the first reversible thermosensitive recording layer and the second reversible thermosensitive recording layer by laser light. Is what you do. However, while this method has an effect of preventing image falsification, it requires a laser beam with a high output of several tens of mW and uses a laser optical system, so that the image recording device becomes large and expensive. There are drawbacks.

[0006]

As described above, the conventional image recording method has problems that the effect of preventing image falsification is small, and that the image recording apparatus is large and expensive. Therefore, an object of the present invention is to provide an image recording medium and an image recording method which have a large effect of preventing image falsification and which can reduce the size and cost of an image recording apparatus.

[0007]

The image recording medium of the present invention is formed on a substrate and on one surface of the substrate, and reversibly changes between a decolored state and a colored state due to a difference in heating energy. A first recording layer; and a second recording layer formed on the first recording layer and reversibly changing between a decolored state and a colored state by a difference in heating energy,
The heating energy for coloring the recording layer and the heating energy for decoloring the first recording layer overlap at least partially.

Further, according to the image recording method of the present invention, a first recording layer which reversibly changes between a decolored state and a colored state due to a difference in heating energy is formed on one surface of a substrate, A second recording layer that reversibly changes between a decolored state and a colored state due to a difference in heating energy on the first recording layer, and a heating energy for decolorizing the second recording layer The heating energy for coloring the second recording layer is greater than that for coloring the second recording layer, and the heating energy for decolorizing the first recording layer is greater than the heating energy for coloring the second recording layer. For an image recording medium in which the heating energy for coloring the first recording layer is larger than the heating energy for decolorizing the one recording layer, the respective heating elements of the heating means including a plurality of heating elements are selectively used. Image by driving An image recording method for recording,
After erasing and heating the entire surface of the first recording layer of the image recording medium, erasing and heating the entire surface of the second recording layer are performed. Thereafter, the recording heating of the first recording layer is performed according to an image to be recorded. And recording heating of the second recording layer selectively and simultaneously, thereby recording an image.

Further, according to the image recording method of the present invention, a first recording layer which reversibly changes between a decolored state and a colored state due to a difference in heating energy is formed on one surface of a base material. A second recording layer that reversibly changes between a decolored state and a colored state due to a difference in heating energy on the first recording layer, and a heating energy for decolorizing the second recording layer The heating energy for coloring the second recording layer is greater than that for heating, and at least a part of the heating energy for coloring the second recording layer and the heating energy for decoloring the first recording layer overlap, For an image recording medium in which the heating energy for coloring the first recording layer is larger than the heating energy for decolorizing the first recording layer,
An image recording method for recording an image by selectively driving each of the heating elements of a heating unit including a plurality of heating elements, wherein the first recording layer of the image recording medium is entirely erased and heated. Performing erasing heating on the entire surface of the second recording layer, and then selectively and simultaneously performing recording heating on the first recording layer and recording heating on the second recording layer in accordance with an image to be recorded. And recording an image.

Further, according to the image recording method of the present invention, a first recording layer which reversibly changes between a decolored state and a colored state due to a difference in heating energy is formed on one surface of a substrate, A second recording layer that reversibly changes between a decolored state and a colored state due to a difference in heating energy on the first recording layer, and a heating energy for decolorizing the second recording layer The heating energy for coloring the second recording layer is greater than that for heating, and at least a part of the heating energy for coloring the second recording layer and the heating energy for decoloring the first recording layer overlap, For an image recording medium in which the heating energy for coloring the first recording layer is larger than the heating energy for decolorizing the first recording layer,
An image recording method for recording an image by selectively driving each of the heating elements of a heating unit including a plurality of heating elements, wherein the entire recording medium is heated by erasing the first recording layer of the image recording medium. The recording heat of the first recording layer and the erasing heat of the non-image portion of the second recording layer are selectively and simultaneously performed according to the image to be recorded. The image is recorded by performing.

Further, according to the image recording method of the present invention, a first recording layer which reversibly changes between a decolored state and a colored state due to a difference in heating energy is formed on one surface of the base material. A second recording layer that reversibly changes between a decolored state and a colored state due to a difference in heating energy on the first recording layer, and a heating energy for decolorizing the second recording layer The heating energy for coloring the second recording layer is greater than that for heating, and at least a part of the heating energy for coloring the second recording layer and the heating energy for decoloring the first recording layer overlap, For an image recording medium in which the heating energy for coloring the first recording layer is larger than the heating energy for decolorizing the first recording layer, each of the first heating means comprising a plurality of heating elements is used. Selectively drive heating elements An image recording method for recording an image by the second consisting of a single or a plurality of heating elements on the upstream side of the image recording medium conveying direction of the first heating means
Heating means for erasing the entire surface of the first recording layer and heating the entire recording area of the second recording layer with the second heating means, and then applying the image to the image recorded by the first heating means. Accordingly, the recording heating of the first recording layer and the erasing heating of the non-image portion of the second recording layer are selectively and simultaneously performed.

According to the present invention, according to an image to be recorded,
The recording heating of the first recording layer and the recording heating of the second recording layer can be performed selectively and simultaneously, whereby the image recorded on the first recording layer and the recording on the second recording layer are recorded. Images can be recorded at accurate positions in dot units.

According to the image to be recorded, it is possible to selectively and simultaneously perform the recording heating of the first recording layer and the non-image portion erasing heating of the second recording layer. The image to be recorded on the layer and the image to be recorded on the second recording layer can be recorded at accurate positions in dot units.

Thus, for example, important information relating to security is recorded on the first recording layer and the second recording layer, and a tint block designed so as not to overlap the information is recorded on the second recording layer. If this is done, it is very difficult to falsify important information related to security so as not to overlap with the tint block, so that the effect of preventing falsification is great.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. First, a first embodiment will be described. FIG. 1 shows a configuration of a rewritable image recording medium 1 according to the present embodiment. That is,
For example, a first reversible thermosensitive recording layer 3 as a first recording layer and a first reversible thermosensitive recording layer 3 as a second recording layer are formed on the surface of a plate-shaped base material 2 formed of a resin such as polyethylene terephthalate (PET). The two reversible thermosensitive recording layers 4 and the protective layer 5 are sequentially laminated in that order. The first reversible thermosensitive recording layer 3 and the second reversible thermosensitive recording layer 4 are, for example, a dye agent mainly called a leuco dye, and a color-reducing agent that reacts with the leuco dye by heating to form a color or to reduce the color. , And can be changed into two states of a color-developed state and a decolored state by a difference in applied heating energy.

Next, the recording and erasing characteristics of the first reversible thermosensitive recording layer 3 and the second reversible thermosensitive recording layer 4 of the image recording medium 1 shown in FIG. 1 will be described with reference to FIG. FIG.
The recording characteristic shown in FIG. 7 is, for example, 8 dots (heating element)
The recording characteristics of the second reversible thermosensitive recording layer 4 are shown by a solid line.
The broken line indicates the recording characteristics of the first reversible thermosensitive recording layer 3.

In FIG. 2, the vertical axis represents the image density, and the horizontal axis represents the heating energy of the thermal head applied to the image recording medium 1. When the heating energy is about 0.2 mJ / dot, the image density of the second reversible thermosensitive recording layer 4 becomes the lowest. When the heating energy is about 0.4 mJ / dot or more, the color of the second reversible thermosensitive recording layer 4 is reduced. The color development state where the image density is highest is obtained. Further, when the heating energy is about 0.6 mJ / dot, the image density of the first reversible thermosensitive recording layer 3 becomes the decoloring state, and when the heating energy is about 0.8 mJ / dot or more, the first reversible thermosensitive recording layer 3 becomes. No. 3 is a color development state in which the image density is the highest. When the heating energy is about 0.8 mJ / dot or more, both the first reversible thermosensitive recording layer 3 and the second reversible thermosensitive recording layer 4 develop color.

FIG. 3 shows the configuration of the image recording apparatus according to this embodiment. The image recording apparatus includes a pair of transport rollers 11, which transport the supplied image recording medium 1,.
A timing sensor 12 for generating a timing for recording on the image recording medium 1 is brought into contact with the conveyed image recording medium 1 and selectively heats the image recording medium 1 on a pixel-by-pixel basis to produce an image. And a platen roller 14 that conveys the image recording medium 1 while pressing the image recording medium 1 from the back surface when recording is performed by the thermal head 13.

In the thermal head 13, based on the image data of the visible image to be recorded, the visible image portion of the first reversible thermosensitive recording layer 3 of the image recording medium 1 is supplied with a heating energy capable of developing a color. Heating energy that can be erased is applied to the visual image part,
Heating energy capable of developing color is applied to the visible image portion of the second reversible thermosensitive recording layer 4 and heating energy capable of decoloring is applied to the invisible image portion. The application of each of the heating energy for coloring and decoloring of the first reversible thermosensitive recording layer 3 and the second reversible thermosensitive recording layer 4 is performed by arranging a plurality of heating elements (heating resistors) in one line. By using a single linear thermal head formed and controlling the heating energy for each heating element, a visible image of the first reversible thermosensitive recording layer 3 and the second reversible thermosensitive recording layer 4 is obtained. The rewriting record is performed.

Next, the control section of the image recording apparatus described with reference to FIG. 3 will be described with reference to FIG. The CPU (Central Processing Unit) 21 has a control unit configured to centrally manage the entire operation via an input / output interface (I / O) 22. That is, each operation described above is managed by the CPU 21, and the setting data such as the conveying speed for conveying the image recording medium 1 and the image data for recording the image are stored in the ROM 21 in advance.
(Read only memory) 23, and is called up in a RAM (random access memory) 24 as needed to set each operation.

When the supply of the image recording medium 1 is detected by the timing sensor 12, a detection signal is sent to the CPU 21.
A transfer start command is issued to the transfer motor drive circuit 27 on the basis of the transfer speed data in the RAM 24 called from the controller.
Thus, the transport motor 27 operates at a preset speed, and rotates the transport roller pair 11 to transport the image recording medium 1 at a predetermined speed. CPU2
1 generates a recording operation timing signal by counting the time from when the timing sensor 12 detects the image recording medium 1, and sends an operation command to the thermal head drive circuit 25.

The thermal head drive circuit 25 drives the thermal head 13 to generate heat in accordance with the arrival of the image recording medium 1 to be transported. Therefore, the erasing of the existing image and the recording of the new image according to the image data are simultaneously performed by the thermal head 13. Further, the transport motor 27
, The image recording medium 1 in which the existing image has been rewritten to the new image is discharged, and the entire operation ends.

Next, the above-described thermal head drive circuit 25 will be described in detail with reference to FIG. FIG. 5 shows a configuration of the thermal head drive circuit 25 in FIG. 4 and its peripheral portion. In this example, in order to change the heating energy of each heating element (heating element) of the heating resistor array 31 of the thermal head 13 between coloring and decoloring, a plurality of energizing pulses are provided in one pixel, and coloring and decoloring are performed. An energizing pulse given by color is selected (details will be described later).

As shown in FIG. 5, in order to realize this embodiment, image data 32a indicating the visible image portion (recording portion) of the first reversible thermosensitive recording layer 3 and the second reversible thermosensitive recording layer 4 Image data 32b indicating a visible image portion (recording portion) of the image data and erase data 33 for deleting the entire area. These three data 32a, 32b, 33 are first sent to the recording / erasing data creating unit 34 in the thermal head drive circuit 25, where the recording unit of the first reversible thermosensitive recording layer 3 and the second reversible thermosensitive recording layer 4 are processed into mixed recording data (recording / erasing data).

Next, the created recording / erasing data is sent to the recording / erasing pulse data calculating section 35, where it is converted into recording pulse and erasing pulse data. As described above, by performing the calculation of the energizing pulse in the thermal head driving circuit 25, the capacity of the image data 32a and 32b prepared in advance can be set to the data amount in pixel units.

The data converted into the recording pulse and the erasing pulse by the recording / erasing pulse data calculating section 35 is sent to the driver 36 of the thermal head 13, and the heating resistor array 31 is driven to generate heat under the above-described conditions. It has become.

Next, an energizing pulse for driving the thermal head 13 will be described with reference to FIG. FIG. 6 shows an energizing pulse (enable signal) for driving the thermal head 13.
(The signal is low active). When there are four energizing pulses in one pixel recording cycle in FIG. 6 and the second reversible thermosensitive recording layer 4 is decolored, the first pulse is used and the second reversible thermosensitive recording layer 4 is colored. Uses the first and second pulses, and uses the first, second, and third pulses to erase the color of the first reversible thermosensitive recording layer 3;
When the reversible thermosensitive recording layer 3 is colored, the first, second, third and fourth pulses are used.

Next, referring to FIG. 7, the recording and heating of the first reversible thermosensitive recording layer 3 of the image recording medium 1 and the second reversible thermosensitive recording layer are performed by a single thermal head according to the image to be recorded. 4
The operation of rewriting and recording an image by selectively and simultaneously performing the recording heating will be described in detail. FIG.
3 schematically shows that an image is recorded on the first reversible thermosensitive recording layer 3 and the second reversible thermosensitive recording layer 4 by a single thermal head 13. In the figure, reference numeral 31 denotes a row of heating resistors of the line-shaped thermal head 13, and the image recording medium 1 in a state where both the first reversible thermosensitive recording layer 3 and the second reversible thermosensitive recording layer 4 are erased. Is moved by the heating resistor array 31 while moving in the direction of the arrow, and records a visible image of the alphabet letter “T” on the first reversible thermosensitive recording layer 3, and the second reversible thermosensitive recording layer 4 2 shows a state in which a visible image of a character frame is recorded at a distance of one dot from the alphabet letter “T”.

Each dot of the character “T” recorded on the first reversible thermosensitive recording layer 3 is schematically indicated by a black circle, and each dot of the character frame of the character “T” recorded on the second reversible thermosensitive recording layer 4 Is schematically indicated by a hatched white circle. Here, the heating resistor array 31 of the thermal head 13 transfers the heating energy to the first pixel in accordance with the image data of the image to be recorded.
Are controlled so as to satisfy the coloring condition of the reversible thermosensitive recording layer 3 and the coloring condition of the second reversible thermosensitive recording layer 4.

In FIG. 7, the elements of the heating resistor array 31 that apply the heating energy of the first reversible thermosensitive recording layer 3 under the coloring condition are painted black, and the second reversible thermosensitive recording layer 4 is colored.
The element giving the heating energy under the coloring condition is indicated by oblique lines.

As described above, the single thermal head 13
By selectively and simultaneously performing the recording heating of the first reversible thermosensitive recording layer 3 and the recording heating of the second reversible thermosensitive recording layer 4 of the image recording medium 1 in accordance with the image to be recorded,
The image recorded on the reversible thermosensitive recording layer 3 and the image recorded on the second reversible thermosensitive recording layer 4 can be recorded at accurate positions in units of one dot.

Next, a recording procedure for realizing the image recording method of the present embodiment will be described with reference to flowcharts shown in FIGS. First, in step S1, when the timing sensor 12 detects the image recording medium 1, the process proceeds to step S1.
2 and turns on the transport motor 27 to switch the image recording medium 1
In the direction of the thermal head 13.

Next, in step S3, it is determined whether or not the recording operation is the first time.
Proceed to. In step S4, the recording / erasing data creation unit 3
4 reads the erase data 33, and proceeds to step S5. In step S5, the recording / erasing pulse data calculation unit 35
Sets an erasing pulse serving as erasing heating energy E3 for erasing the color of the first reversible thermosensitive recording layer 3.

Next, after delaying the time until the image recording medium 1 reaches the position of the thermal head 13 in step S6, the recording operation is performed by the thermal head 13 in step S7, whereby the first reversible thermosensitive recording is performed. An erasing operation for erasing the entire surface of the layer 3 is performed.

Next, in step S8, it is determined whether or not the recording operation has been completed.
Then, the process proceeds to step S9, where the transport motor 27 is turned off, and the first recording operation is completed. In the first recording operation, an erasing operation for erasing the entire surface of the first reversible thermosensitive recording layer 3 is performed.

Next, the second recording operation will be described. Steps S1 and S2 are the same as the first recording operation, and a description thereof will be omitted. If it is determined in steps S3 and S10 that the recording operation is the second time (other than the first time), the process proceeds to step S11. In step S11, as in the first time, the recording / erasing data creation unit 34 reads the erasing data 33, and proceeds to step S12. In step S12,
The recording / erasing pulse data calculation unit 35 sets an erasing pulse that becomes the erasing heating energy E1 for erasing the color of the second reversible thermosensitive recording layer 4.

After that, similarly to the first recording operation, steps S6 to S9 are executed, and the second recording operation ends. In the second recording operation, an erasing operation for erasing the entire surface of the second reversible thermosensitive recording layer 4 is performed.

Next, the third recording operation will be described. Steps S1, S2, and S3 are the same as those in the second recording operation, and a description thereof will be omitted. If it is determined in step S10 that the recording operation is the third time (if not the second time), the process proceeds to step S13. In step S13, the recording / erasing data creating unit 34 sets the first reversible recording image data 32
a and the second image data 32b for reversible recording are read out, and the process proceeds to step S14. In step S14, the first reversible recording image data 32a and the second reversible recording image data 32b are combined.

Next, in step S15, the pixel of interest is the first
Judge whether the image is a reversible recording image or a second reversible recording image,
If the target pixel is the first reversible recording image, step S1
Proceed to 6. In step S16, a recording pulse serving as recording heating energy E4 for coloring the first reversible thermosensitive recording layer 3 is set.

In step S15, if the target pixel is the second reversible recording image, the flow advances to step S17. In step S17, a recording pulse serving as recording heating energy E2 for causing the second reversible thermosensitive recording layer 4 to develop color is set.

Thereafter, as in the first and second recording operations, steps S6 to S9 are executed, and the third recording operation is completed. In the third recording operation, the recording operation for coloring the first reversible thermosensitive recording layer 3 and the second reversible thermosensitive recording layer 4 is performed simultaneously.

As described above, in the first embodiment, the entire recording heating of the first reversible thermosensitive recording layer 3 is performed in the first recording operation, and the second reversible thermosensitive recording is performed in the second recording operation. The entire erasing heating of the layer 4 is performed, and in the third recording operation, the recording heating of the first reversible thermosensitive recording layer 3 and the recording heating of the second reversible thermosensitive recording layer 4 are selectively and depending on the image to be recorded. Simultaneously, an image is recorded.

Therefore, in the image recording method of the first embodiment, the rewriting recording of the first reversible thermosensitive recording layer 3 of the image recording medium 1 and the rewriting recording of the second reversible thermosensitive recording layer 4 are performed by three times.
Can be done with a pass.

Next, a second embodiment will be described. Note that the configuration of the image recording apparatus according to the present embodiment, the configuration of the control unit, and the like are the same as those in the first embodiment described above, and thus description thereof will be omitted.

FIG. 10 shows the recording / erasing characteristics of the first reversible thermosensitive recording layer 3 and the second reversible thermosensitive recording layer 4 of the image recording medium 1 shown in FIG. The recording characteristics shown in FIG. 10 are, for example, the recording characteristics of a thermal head having a resolution of 8 dots (heating elements) / mm.
The solid line indicates the recording characteristics of the second reversible thermosensitive recording layer 4, and the broken line indicates the recording characteristics of the first reversible thermosensitive recording layer 3.

In FIG. 10, the vertical axis represents the image density, and the horizontal axis represents the heating energy of the thermal head applied to the image recording medium 1. When the heating energy is about 0.2 mJ / dot, the image density of the second reversible thermosensitive recording layer 4 becomes the lowest. When the heating energy is about 0.4 mJ / dot or more, the color of the second reversible thermosensitive recording layer 4 is reduced. The color development state where the image density is highest is obtained. When the heating energy is about 0.4 mJ / dot, the first reversible thermosensitive recording layer 3 is in the decolored state where the image density is the lowest. When the heating energy is about 0.6 mJ / dot or more, the first reversible thermosensitive recording layer 3 is in the decolored state. No. 3 is a color development state in which the image density is the highest. When the heating energy is about 0.6 mJ / dot or more, both the first reversible thermosensitive recording layer 3 and the second reversible thermosensitive recording layer 4 develop color. This recording characteristic is such that the heating energy for coloring the second reversible thermosensitive recording layer 4 and the heating energy for decolorizing the first reversible thermosensitive recording layer 3 are about 0.4.
The feature is that they overlap at mJ / dot.

By doing so, the heating energy for decoloring the first reversible thermosensitive recording layer 3 and the heating energy for coloring the color are each approximately 0.1 mm compared to the recording characteristics shown in FIG.
Since 2 mJ / dot can be reduced, the heating energy of the thermal head is reduced, and the durability of the thermal head is improved.
In addition, since the thermal stress of the protective layer 5 is reduced, the repetition durability of the image recording medium 1 is also improved.

Next, an energizing pulse for driving the thermal head 13 for the image recording medium 1 having the recording characteristics shown in FIG. 10 will be described with reference to FIG. FIG. 11 shows an energizing pulse (enable signal) for driving the thermal head 13 (the signal is low active). There are three energizing pulses within one pixel recording cycle in FIG. 11, and when the second reversible thermosensitive recording layer 4 is decolored, the first pulse is used,
When the second reversible thermosensitive recording layer 4 is colored and the first reversible thermosensitive recording layer 3 is decolored, the first and second pulses are used to color the first reversible thermosensitive recording layer 3. In this case, the first, second and third pulses are used.

Next, a recording procedure for realizing the image recording method of this embodiment will be described with reference to flowcharts shown in FIGS. The description of the same portions as those in the flowcharts of the first embodiment in FIGS. 8 and 9 will be omitted, and only different portions will be described.

In step S5, the recording / erasing pulse data calculating section 35 sets an erasing pulse which becomes erasing heating energy E2 for erasing the first reversible thermosensitive recording layer 3. In step S16, a recording pulse serving as recording heating energy E3 for causing the first reversible thermosensitive recording layer 3 to develop color is set.

As described above, in the second embodiment, the entire recording heating of the first reversible thermosensitive recording layer 3 is performed in the first recording operation, and the second reversible thermosensitive recording is performed in the second recording operation. The entire erasing heating of the layer 4 is performed, and in the third recording operation, the recording heating of the first reversible thermosensitive recording layer 3 and the recording heating of the second reversible thermosensitive recording layer 4 are selectively and depending on the image to be recorded. Simultaneously, an image is recorded.

Therefore, in the image recording method of the second embodiment, rewriting recording of the first reversible thermosensitive recording layer 3 of the image recording medium 1 and rewriting recording of the second reversible thermosensitive recording layer 4 are performed in three passes. Can do it.

Next, a third embodiment will be described. As described above, in the first and second embodiments, the recording process by the thermal head
In the third embodiment, the number of recording steps by the thermal head 13 is reduced to two to increase the processing speed, and the third embodiment will be described below.

The image recording medium 1 according to the present embodiment
Configuration, the configuration of the image recording apparatus, the configuration of the control unit, and
The energizing pulse for driving the thermal head 13 and the like are the same as in the above-described second embodiment, and a description thereof will be omitted.

Referring to FIG. 14, the recording of the first reversible thermosensitive recording layer 3 of the image recording medium 1 and the non-reversal of the second reversible thermosensitive recording layer 4 are performed by a single thermal head according to the image to be recorded. The operation of recording an image by selectively and simultaneously performing the image portion erasing heating will be described in detail. FIG.
Reference numeral 4 schematically shows a state in which an image is recorded on the first reversible thermosensitive recording layer 3 and the second reversible thermosensitive recording layer 4 by a single thermal head 13. In the figure, reference numeral 31 denotes a row of heating resistors of the line-type thermal head 13, in which the first reversible thermosensitive recording layer 3 is in a decolored state and the second reversible thermosensitive recording layer 4 is in a colored state (shown by hatching). Of the heating resistor array 31 while moving in the direction of the arrow.
, A visible image of the alphabet letter "T" is recorded on the first reversible thermosensitive recording layer 3, and the second reversible thermosensitive recording layer 4 is separated from the alphabetic letter "T" by one dot and has a character frame. Is recorded by erasing the non-image portion.

Each dot of the character “T” recorded on the first reversible thermosensitive recording layer 3 is schematically indicated by a black circle, and the character frame (T hatched) of the character “T” recorded on the second reversible thermosensitive recording layer 4 The dots from which the non-image portions other than those have been deleted are shown in white. Here, the heating resistor array 31 of the thermal head 13 uses the heating energy for each pixel in accordance with the image data of the image to be recorded, in accordance with the coloring condition of the first reversible thermosensitive recording layer 3 and the second reversible thermosensitive recording. Control is performed so that the decoloring condition of the layer 4 is satisfied.

In FIG. 14, the heating resistor array 31
The element giving the heating energy of the first reversible thermosensitive recording layer 3 under the coloring condition is blacked out, and the element giving the heating energy of the second reversible thermosensitive recording layer 4 under the decoloring condition is indicated by a horizontal line. .

As described above, the single thermal head 13
According to the image to be recorded, the first reversible thermosensitive recording layer 3 of the image recording medium 1 is heated for recording and the second reversible thermosensitive recording layer 4 is heated.
And decolorizing heating of the non-image portion is selectively and simultaneously performed, so that an image to be recorded on the first reversible thermosensitive recording layer 3;
An image to be recorded on the second reversible thermosensitive recording layer 4 can be recorded at an accurate position in units of one dot.

Next, a recording procedure for realizing the image recording method of the present embodiment will be described with reference to the flowcharts shown in FIGS. First, in step S21, when the timing sensor 12 detects the image recording medium 1, the process proceeds to step S22, in which the conveyance motor 27 is turned on to convey the image recording medium 1 in the direction of the thermal head 13.

Next, at step S23, it is determined whether or not the recording operation is the first time.
Proceed to 24. In step S24, the recording / erasing data creation unit 34 reads the erasing data 33, and proceeds to step S25. In step S25, the recording / erasing pulse data calculation unit 35 sets an erasing pulse that becomes the erasing heating energy E2 for erasing the color of the first reversible thermosensitive recording layer 3.

Next, in step S26, the image recording medium 1
After extending the time until the recording head reaches the position of the thermal head 13, the recording operation is performed by the thermal head 13 in step S27 to erase the entire surface of the first reversible thermosensitive recording layer 3 and the second operation. The recording operation for coloring the entire surface of the reversible thermosensitive recording layer 4 is performed simultaneously.

Next, in step S28, it is determined whether or not the recording operation has been completed. When the recording operation has been completed, the process proceeds to step S29, in which the transport motor 27 is turned off, and the first recording operation is completed. In the first recording operation, the entire reversal heating of the first reversible thermosensitive recording layer 3 and the second reversible thermosensitive recording layer 4 are performed.
And recording heating of the entire surface are simultaneously performed.

Next, the second recording operation will be described. Steps S21 and S22 are the same as the first recording operation, and a description thereof will be omitted. If it is determined in step S23 that the recording operation is the second time (if not the first time), the process proceeds to step S30. In step S30, the recording / erasing data creation unit 34 sets the first reversible recording image data 32
a and the second reversible recording image data 32b are read out, and the flow advances to step S31.

In step S31, the second reversible thermosensitive recording layer 4 is recorded by erasing the non-image portion, so that the second reversible recording image data 32b is inverted. Next, in step S32, the first reversible recording image data 32a and the inverted data of the second reversible recording image data 32b are combined.

Next, in step S33, the pixel of interest is the first
Judge whether the image is a reversible recording image or a second reversible recording image,
If the target pixel is the first reversible recording image, step S3
Proceed to 4. In step S34, a recording pulse serving as recording heating energy E3 for causing the first reversible thermosensitive recording layer 3 to develop color is set.

In step S33, if the target pixel is the second reversible recording image, the flow advances to step S35. In step S35, a recording pulse serving as erasing heating energy E1 for erasing the second reversible thermosensitive recording layer 4 is set.

Thereafter, similarly to the first recording operation, steps S26 to S29 are executed, and the second recording operation ends. In the second recording operation, a recording operation for coloring the first reversible thermosensitive recording layer 3 and a recording operation for decoloring the second reversible thermosensitive recording layer 4 are performed simultaneously.

As described above, in the third embodiment, the entire recording erasing heating of the first reversible thermosensitive recording layer 3 and the entire recording heating of the second reversible thermosensitive recording layer 4 are performed in the first recording operation. In the second recording operation, the recording heating of the first reversible thermosensitive recording layer 3 and the erasing heating of the non-image portion of the second reversible thermosensitive recording layer 4 are selectively and simultaneously performed in accordance with the image to be recorded. Thus, an image is recorded.

Therefore, in the image recording method of the third embodiment, rewriting recording of the first reversible thermosensitive recording layer 3 of the image recording medium 1 and rewriting recording of the second reversible thermosensitive recording layer 4 are performed in two passes. Can do it.

Next, a fourth embodiment will be described. In the fourth embodiment, the processing is further speeded up, which will be described below.

The image recording medium 1 according to the present embodiment
The configuration, the energizing pulse for driving the thermal head 13, and the like are the same as those in the above-described second embodiment, and a description thereof will be omitted.

FIG. 17 shows the configuration of the image recording apparatus according to the present embodiment. In this image recording apparatus, two thermal heads 13a and 13b for rewriting and recording an image on a conveyed image recording medium 1 are arranged side by side in the conveying direction of the image recording medium 1, and these thermal heads 13a and 13b are arranged in parallel. 13 is different from the image recording apparatus shown in FIG. 3 in that two platen rollers 14a and 14b are provided to convey the image recording medium 1 while pressing the image recording medium 1 from the back surface. Therefore, the description is omitted.

FIG. 18 shows a control section of the image recording apparatus described with reference to FIG. 17, and FIG. 19 shows details of the thermal head drive circuit 25 in FIG. Thermal head 13a, 1
Except for the configuration in which 3b is driven by the thermal head driving circuit 25, the control unit is the same as the control unit in FIG. In FIG. 19, reference numerals 31a and 31b denote heating resistor arrays,
36a and 36b are drivers.

Next, a recording procedure for realizing the image recording method of this embodiment will be described with reference to the flowcharts shown in FIGS. First, in step S41, when the timing sensor 12 detects the image recording medium 1, the process proceeds to step S42, in which the transport motor 27 is turned on to transport the image recording medium 1 in the direction of the thermal head 13a.

Next, the flow branches to step S43 and step S48, and the processing after step S43 and step S4
8 and subsequent processes are performed simultaneously. First, processing after step S43 will be described.

In step S43, the recording / erasing data creating section 34 reads out the erasing data 33, and proceeds to step S44. In step S44, the recording / erasing pulse data calculation unit 35 sets an erasing pulse that becomes the erasing heating energy E2 for erasing the color of the first reversible thermosensitive recording layer 3.

Next, in step S45, the image recording medium 1
After delaying the time until the recording head reaches the position of the thermal head 13a, a recording operation is performed by the thermal head 13a in step S46, whereby an erasing operation for erasing the entire surface of the first reversible thermosensitive recording layer 3 and a second erasing operation are performed. The recording operation for coloring the entire surface of the reversible thermosensitive recording layer 4 is performed simultaneously. Then, it waits for the recording operation to end in step S47,
When the recording operation ends, the recording operation by the thermal head 13a ends.

Next, the processing after step S48 will be described. In step S48, the recording / erasing data creation unit 34 reads out the first image data 32a for reversible recording and the second image data 32b for reversible recording, and proceeds to step S4.
Go to 9.

In step S49, the second reversible thermosensitive recording layer 4 is recorded by erasing the non-image portion, so that the second reversible recording image data 32b is inverted. Next, in step S50, the first reversible recording image data 32a and the inverted data of the second reversible recording image data 32b are combined.

Next, in step S51, the pixel of interest is the first
Judge whether the image is a reversible recording image or a second reversible recording image,
If the target pixel is the first reversible recording image, step S5
Proceed to 2. In step S52, a recording pulse serving as recording heating energy E3 for coloring the first reversible thermosensitive recording layer 3 is set.

If it is determined in step S51 that the pixel of interest is the second reversible recording image, the flow advances to step S53. In step S53, a recording pulse serving as erasing heating energy E1 for erasing the second reversible thermosensitive recording layer 4 is set.

Next, in step S54, the image recording medium 1
After a time delay until the recording head reaches the position of the thermal head 13b, the recording operation of the first reversible thermosensitive recording layer 3 is performed by performing the recording operation by the thermal head 13b in step S55, and the second reversible thermosensitive recording is performed. An erasing operation for erasing the recording layer 4 is performed simultaneously.

Next, in step S56, it is determined whether or not the recording operation has been completed. When the recording operation has been completed, the process proceeds to step S57, in which the conveying motor 27 is turned off, and the recording operation ends.

As described above, in the fourth embodiment, the thermal head 1
After performing the entire erasing heating of the first reversible thermosensitive recording layer 3 and the entire recording heating of the second reversible thermosensitive recording layer 4 simultaneously by the recording operation of 3a, the recording operation by the thermal head 13b is performed according to the image to be recorded. The image is recorded by selectively and simultaneously performing the recording heating of the first reversible thermosensitive recording layer 3 and the erasing heating of the non-image portion of the second reversible thermosensitive recording layer 4.

Therefore, in the image recording method of the fourth embodiment, the rewriting recording of the first reversible thermosensitive recording layer 3 of the image recording medium 1 and the rewriting recording of the second reversible thermosensitive recording layer 4 are performed in one pass. Can do it.

In the fourth embodiment, the erasing operation for erasing the entire surface of the first reversible thermosensitive recording layer 3 is performed using a thermal head. However, the present invention is not limited to this.
The same operation and effect can be obtained by using a thermal bar or the like formed of a single elongated heating element in a line shape.

[0087]

As described above in detail, according to the present invention, it is possible to provide an image recording medium and an image recording method which have a large effect of preventing image falsification and which can reduce the size and cost of an image recording apparatus. .

[Brief description of the drawings]

FIG. 1 is a cross-sectional view schematically showing a configuration of an image recording medium according to an embodiment of the present invention.

FIG. 2 is a diagram showing recording and erasing characteristics of the image recording medium shown in FIG.

FIG. 3 is a configuration diagram schematically showing a configuration of the image recording apparatus according to the first embodiment.

FIG. 4 is a block diagram illustrating a configuration of a control unit of the image recording apparatus according to the first embodiment.

FIG. 5 is a block diagram showing a configuration of a thermal head driving circuit and its peripheral portion in FIG. 4;

FIG. 6 is a diagram showing drive energizing pulses of the thermal head according to the first embodiment.

FIG. 7 is a diagram schematically showing a state in which a first reversible thermosensitive recording layer and a second reversible thermosensitive recording layer are simultaneously recorded by a thermal head in the first embodiment.

FIG. 8 is a flowchart illustrating a procedure of an image recording method according to the first embodiment.

FIG. 9 is a flowchart illustrating a procedure of an image recording method according to the first embodiment.

FIG. 10 is a diagram illustrating recording and erasing characteristics of an image recording medium according to a second embodiment.

FIG. 11 is a diagram showing drive energizing pulses of a thermal head according to a second embodiment.

FIG. 12 is a flowchart illustrating a procedure of an image recording method according to a second embodiment.

FIG. 13 is a flowchart illustrating a procedure of an image recording method according to the second embodiment.

FIG. 14 is a view schematically showing a state in which a first reversible thermosensitive recording layer and a second reversible thermosensitive recording layer are simultaneously recorded by a thermal head in the third embodiment.

FIG. 15 is a flowchart illustrating a procedure of an image recording method according to a third embodiment.

FIG. 16 is a flowchart illustrating a procedure of an image recording method according to a third embodiment.

FIG. 17 is a configuration diagram schematically illustrating a configuration of an image recording apparatus according to a fourth embodiment.

FIG. 18 is a block diagram illustrating a configuration of a control unit of an image recording apparatus according to a fourth embodiment.

FIG. 19 is a block diagram showing a configuration of a thermal head driving circuit and its peripheral portion in FIG. 18;

FIG. 20 is a flowchart illustrating a procedure of an image recording method according to a fourth embodiment.

FIG. 21 is a flowchart illustrating a procedure of an image recording method according to a fourth embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Image recording medium, 2 ... Substrate, 3 ... First reversible thermosensitive recording layer (first recording layer), 4 ... Second reversible thermosensitive recording layer (second recording layer), 11 …… Transport roller pair, 12 ……
Timing sensors, 13, 13a, 13b ... thermal head (heating means), 14 ... platen roller, 21 ...
... CPU, 23 ... ROM, 24 ... RAM, 25 ...
Thermal head drive circuit 26 Transport motor drive circuit 26 Transport motor 31 Heating resistor array (heating element) 32a First reversible recording image data 32b
... Second reversible recording image data, 33.
4 ... record / erase data generator, 35 ... record / erase pulse data calculator, 55 ... driver.

Continuation of the front page (72) Inventor Shinichi Ito 70 Yanagicho, Saiwai-ku, Kawasaki City, Kanagawa Prefecture

Claims (7)

[Claims] A first recording layer formed on one surface of the substrate and reversibly changing between a decolored state and a colored state due to a difference in heating energy; A second layer formed on the layer and reversibly changing between a decolored state and a colored state due to a difference in heating energy;
And a heating energy for coloring the second recording layer and the first recording layer.
An image recording medium characterized in that at least a part of the heating energy for decolorizing the recording layer is overlapped. 2. A heating energy for coloring the second recording layer is larger than a heating energy for decoloring the second recording layer, and is larger than a heating energy for coloring the second recording layer. The heating energy for decolorizing the first recording layer is larger, and the heating energy for coloring the first recording layer is larger than the heating energy for decolorizing the first recording layer. Claim 1.
The image recording medium described in the above. 3. The heating energy for coloring the second recording layer is larger than the heating energy for decolorizing the second recording layer, and the heating energy for coloring the second recording layer and the heating energy for coloring the second recording layer are different from each other. At least a part of the heating energy for decoloring the first recording layer overlaps, and the heating energy for coloring the first recording layer is larger than the heating energy for decolorizing the first recording layer. 2. The image recording medium according to claim 1, wherein: 4. A first recording layer reversibly changing between a decolored state and a colored state due to a difference in heating energy is formed on one surface of a base material, and a heating layer is formed on the first recording layer. Forming a second recording layer which reversibly changes between a decolored state and a colored state due to a difference in energy, and wherein the second recording layer has a heating energy that decolorizes the second recording layer;
The heating energy for coloring the recording layer is larger than the heating energy for coloring the second recording layer.
The heating energy for decolorizing the recording layer is larger than the heating energy for decolorizing the first recording layer.
An image recording method for recording an image by selectively driving each of said heating elements of a heating means comprising a plurality of heating elements on an image recording medium having a larger heating energy for coloring the recording layer. After erasing and heating the entire first recording layer of the image recording medium, erasing and heating the entire surface of the second recording layer is performed, and thereafter, recording of the first recording layer is performed according to an image to be recorded. An image recording method, wherein an image is recorded by selectively and simultaneously performing heating and recording heating of the second recording layer. 5. A first recording layer which is reversibly changed between a decolored state and a colored state due to a difference in heating energy on one surface of a base material, and a heating layer is formed on the first recording layer. Forming a second recording layer which reversibly changes between a decolored state and a colored state due to a difference in energy, and wherein the second recording layer has a heating energy that decolorizes the second recording layer;
The heating energy for coloring the second recording layer is greater than the heating energy for coloring the second recording layer, and at least a part of the heating energy for decoloring the first recording layer overlaps with the first recording layer. For the image recording medium in which the heating energy for coloring the first recording layer is larger than the heating energy for decoloring the layer, each of the heating elements of the heating means including a plurality of heating elements is selectively driven. An image recording method for recording an image by heating the first recording layer of the image recording medium over the entire surface, and then heating the entire surface of the second recording layer to erase the image. Recording an image by selectively and simultaneously performing the recording heating of the first recording layer and the recording heating of the second recording layer in accordance with the method. 6. A first recording layer which reversibly changes between a decolored state and a colored state due to a difference in heating energy is formed on one surface of a base material, and a heating layer is formed on the first recording layer. Forming a second recording layer which reversibly changes between a decolored state and a colored state due to a difference in energy, and wherein the second recording layer has a heating energy that decolorizes the second recording layer;
The heating energy for coloring the second recording layer is greater than the heating energy for coloring the second recording layer, and at least a part of the heating energy for decoloring the first recording layer overlaps with the first recording layer. For the image recording medium in which the heating energy for coloring the first recording layer is larger than the heating energy for decoloring the layer, each of the heating elements of the heating means including a plurality of heating elements is selectively driven. An image recording method for recording an image by simultaneously performing heating for erasing the entire surface of the first recording layer of the image recording medium and heating for recording the entire surface of the second recording layer at the same time. An image recording method for selectively and simultaneously performing recording heating of the first recording layer and erasing heating of a non-image portion of the second recording layer to record an image. 7. A first recording layer which reversibly changes between a decolored state and a colored state due to a difference in heating energy on one surface of a base material, and a heating layer is formed on the first recording layer. Forming a second recording layer which reversibly changes between a decolored state and a colored state due to a difference in energy, and wherein the second recording layer has a heating energy that decolorizes the second recording layer;
The heating energy for coloring the second recording layer is greater than the heating energy for coloring the second recording layer, and at least a part of the heating energy for decoloring the first recording layer overlaps with the first recording layer. For an image recording medium in which the heating energy for coloring the first recording layer is larger than the heating energy for decoloring the layer, the respective heating elements of the first heating means including a plurality of heating elements are selectively used. An image recording method for recording an image by driving the second heating means comprising a single or a plurality of heating elements upstream of the first heating means in the image recording medium transport direction. A second heating unit performs erasing heating of the entire surface of the first recording layer and heating of the entire recording surface of the second recording layer, and then performs the first recording according to an image recorded by the first heating unit. Recording heating of the layer and the second An image recording method, wherein erasing heating to a non-image portion of a recording layer is performed selectively and simultaneously.