JPH08244359A - Method and apparatus for erasing visible image and visible image recorder - Google Patents

Abstract

PURPOSE: To provide a method and an apparatus for erasing a visible image in which the visible image of a recording medium which is conveyed at a high speed without altering the conveying speed of the medium at the times of erasing and recording can be effectively erased and the image can be effectively erased even if the environmental temperature is changed and a visible image recorder. CONSTITUTION: A heat roller 4 erases a visible image by erasing and heating the visible image recorded surface of a recording medium 1 supplied by supply roller pairs 2, 3. The medium 1 in which the image is erased is entirely sandwiched between conveying belts 8 and 12 heated at both the surfaces by the roller 4, and conveyed to a thermal head 18. The medium 1 conveyed by the belts 8, 12 is heat insulated from both the surfaces by the belt 8 having thermal storage function and the belt 12 heated by the radiation heat from the roller 4, and heat insulated to be heated by a tungsten lamp 16 via the belt 8.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention provides, for example, by making heat cloudy or transparent by controlling heat energy,
A visible image erasing method and a visible image erasing apparatus for performing thermal erasing of a visible image on a recording medium capable of repeating recording or erasing of a visible image by using a heat erasing means, and using the same. The present invention relates to a visible image recording device that records a visible image on the recording medium.

[0002]

2. Description of the Related Art A conventional hard copy forms an image on a recording medium such as paper from the outside with a visual material such as ink or toner, or, like a thermal recording paper,
A permanent image is recorded by providing a recording layer on a substrate such as paper and forming a visible image on the recording layer.

However, with the recent construction of various network networks and the widespread use of facsimiles and copying machines, a rapid increase in the consumption of these recording media is caused by the problems of natural destruction such as deforestation and social problems such as waste disposal. Is causing. In order to deal with these problems, it is strongly demanded to reduce the consumption amount of the recording medium such as reproduction of recording paper. In response to such a problem, a recording medium that can be repeatedly recorded / erased has recently attracted attention.

Therefore, as a recording medium having such characteristics, there has been proposed a recording medium capable of reversibly changing both the transparent state and the cloudy state depending on the temperature applied to the recording material (for example, JP-A-55-154198). (See the official gazette).

For example, in the transparent state, this recording medium changes from the transparent state to the cloudy state when the temperature is raised to T1 and maintains the cloudy state as it is even after returning to room temperature. Then, the temperature of the recording medium is set to T2 (T2 <T1
) And return to room temperature again, the cloudy state changes to a transparent state, and the transparent state is maintained as it is. This change can be repeatedly reproduced.

These recording media have the sensitivity of white turbidity or color development to the sensitivity of conventional thermal recording paper, and the state changes with heating time of about several ms using a thermal head. However, the change in transparency or decolorization is slow, and therefore, the transparent or decolorization is performed with a heating time of a second level by a hot stamp or the like, which makes it difficult to process in a short time.

In order to solve such a problem, a technique of making the heating time for erasing (decoloring or making transparent) a visible image longer than the heating time for recording (coloring or clouding) (see, for example, Japanese Patent Laid-Open No. JP-A-4-44887 and JP-A-5-169.
No. 841), or a technique of repeatedly erasing by using a plurality of heat rollers, or nipping and conveying a recording medium with a heat belt heated to the erasing temperature, and heating during the time of conveyance (for example, Japanese Patent Laid-Open No. Hei 8 (1999) -83242). 3-142279 gazette) etc. are proposed.

[0008]

However, in the above-mentioned method of changing the heating time during erasing and during recording, there is a problem that since the processing time is different, the conveying speed of the recording medium must be changed. Further, the method of providing a plurality of heating means has a problem that the apparatus becomes large-sized, and the method of sandwiching with a heat belt keeps the recording medium at an erasable temperature for a long time. In a recording medium of a type in which is dispersed in a polymer, there is a problem that phase separation is promoted and the life of the recording medium is shortened. Further, there are problems such as power supply to a moving heat belt and no heat belt having sufficient mechanical strength.

Therefore, according to the present invention, the visible image of the recording medium conveyed at high speed can be surely erased without changing the conveying speed of the recording medium between the time of erasing the visible image and the time of recording, and the environmental temperature can be surely erased. It is an object of the present invention to provide a visible image erasing method, a visible image erasing device, and a visible image recording device that can surely erase a visible image even when the value changes.

[0010]

The visible image erasing method according to the present invention is a method of recording and erasing a visible image by thermal history of different temperatures.
Showing the two states, and for the recording medium to be transported,
A visible image erasing method for erasing a visible image using a heat erasing means, wherein erasing heating for erasing a visible image on a visible image recording surface of the recording medium is performed for a predetermined time, After the erasing and heating, the visible image recording surface of the recording medium is heated and kept at a temperature not higher than the erasable temperature of the visible image for a time longer than the erasing and heating time.

The visible image erasing device of the present invention further comprises a first conveying means for conveying a recording medium showing two states of recording and erasing a visible image by thermal histories of different temperatures, and the first conveying means. Thermal erasing means for erasing the visible image by erasing and heating the visible image recording surface of the recording medium conveyed by the conveying means, and the recording in which the visible image is erased by the thermal erasing means. Second transport means for transporting the medium while sandwiching both sides thereof with belt-shaped transport members over the entire surface, and at least the visible image recording surface of the recording medium transported by the second transport means for the second transport. The heating means for keeping the temperature of the heating means via the belt-shaped conveying member.

Further, the visible image erasing device of the present invention conveys a recording medium showing two states of recording and erasing a visible image by thermal histories of different temperatures, and the conveying means. A planar shape that is disposed so as to face the visible image recording surface of the recording medium and that has a coarse heating element density so that the heat generation temperature decreases from the upstream side to the downstream side of the recording medium in the transport direction. After heating the visible image recording surface of the recording medium by erasing and heating, the visible image recording surface is maintained at a temperature range below the visible image erasing temperature and above the ambient temperature. And a heating means for gradually cooling.

Further, the visible image erasing device of the present invention conveys a recording medium showing two states of recording and erasing a visible image by thermal histories of different temperatures, and the conveying means conveys the recording medium. Facing the visible image recording surface of the recording medium, and
The recording medium is composed of a planar heating element arranged so that the distance from the upstream side to the downstream side of the recording medium becomes wider from the upstream side to the downstream side, and erasing heating is performed on the visible image recording surface of the recording medium. After performing the above step, the visible image recording surface is maintained at a temperature range not higher than the visible image erasing temperature and not lower than the ambient temperature and is gradually cooled.

Further, the visible image recording apparatus of the present invention conveys a recording medium showing two states of recording and erasing a visible image by thermal histories of different temperatures, and the conveying means. A thermal erasing means for erasing a visible image by erasing and heating the visible image recording surface of the recording medium, and a visible image recording surface of the recording medium after the erasing and heating by the thermal erasing means. A heating means for keeping warm for a time longer than the erasing heating time at a temperature not higher than the erasable temperature of the visible image, and a visible image on the visible image recording surface of the recording medium after the warm heating of the heating means. Thermal recording means for recording.

[0015]

According to the present invention, after erasing and heating, heat is applied to the visible image recording surface of the recording medium to keep the visible image recording surface of the recording medium warm and prevent it from being rapidly cooled. After erasing and heating, the visible image recording surface of the recording medium is heated at a temperature not higher than the erasable temperature of the visible image for a time longer than the erasing heating time. As a result, the visible image of the recording medium conveyed at high speed can be surely erased without changing the conveying speed of the recording medium between the time of erasing the visible image and the time of recording. Further, since the temperature is kept constant regardless of the environmental temperature, the visible image can be surely erased even if the environmental temperature changes.

[0016]

First, the outline of the present invention will be described before describing the embodiments. Conventionally, a recording medium using a low molecular weight / polymer composite film rewritable recording material in which a low molecular weight organic substance is dispersed in a polymer matrix is changed to transparency, or a recording medium using a leuco-type rewritable recording material is changed. In the decoloring change, there is known a method of reliably performing the decolorization or the decolorization by prolonging the time for maintaining the recording medium at the decolorization temperature or the decolorization temperature.

In the present invention, the degree of decoloring varies depending on whether or not the recording medium is kept warm during the process of cooling the recording medium after heating it to change from cloudiness to transparent or from coloring to decoloring. It was made based on the finding that the degree of transparency or decoloring is improved by cooling while cooling.

FIG. 5 shows a recording in a cloudy state by using a low molecular weight / polymer composite film recording material by an apparatus in which an erasing stage by a thermal head and a heat retaining stage by a heating lamp are provided at the subsequent stage in the recording medium conveying direction. It shows the relationship between the transport speed and the erase density when the material is changed to the transparent state. In the figure, x indicates that there is no heat retention by the heating lamp, and o indicates that there is heat retention. The direction in which the reflection density value is low indicates that the transparency is changing.
Up to a conveyance speed of about 30 mm / s, there was no difference in the degree of transparency change regardless of the presence or absence of heat retention, and both were able to be transparent up to the background density. However, if there is no heat insulation, the transport speed is 3
When it is over 0 mm / s, the transparency change becomes insufficient. On the other hand, when there was heat retention, the decrease in transparency change was small, and the decrease was slight.

Embodiments of the present invention will be described below with reference to the drawings. First, a first embodiment will be described.
FIG. 1 schematically shows a configuration of a visible image recording device to which the visible image erasing device according to the first embodiment is applied. In FIG. 1, reference numeral 1 denotes a recording medium capable of repeatedly recording / erasing a visible image by heat, and a recording surface (visible image recording surface) side on which recording / erasing is performed contacts a conveyor belt 8 described later, In other words, the supply roller pair 2 and 3 supplies and conveys the upper side of the drawing. The supply roller pairs 2 and 3 are rotationally driven by a driving unit (motor or the like) not shown.

Reference numeral 4 is a heat roller as heat erasing means,
It is composed of a rotating metal sleeve 5 whose surface is coated with urethane rubber, and a heat generating lamp 6 as a heat generating element disposed inside thereof. The heat roller 4 is rotationally driven by a driving unit (motor or the like) not shown. The heat generating lamp 6 is driven by a heat roller temperature control circuit (not shown).

The temperature sensor 7 as a temperature detecting means detects the surface temperature of the heat roller 4 and sends its output to a heat roller temperature control circuit (not shown). The heat roller temperature control circuit controls the temperature of the heat roller 4 to a predetermined temperature according to the output signal of the temperature sensor 7.

Reference numeral 8 denotes a conveyor belt which also serves as a conveyor and also serves as a heat insulator. For example, the conveyor belt has a two-layer structure including a metal film and a heat storage film having relatively poor thermal conductivity such as rubber or plastics.
The endless belt has a width wider than the width of the recording medium 1 (width in the direction orthogonal to the transport direction). Here, a polyester film is used as the heat storage layer, and the transport belt 8 is stretched between the heat roller 4 and the transport rollers 9 and 10 so that the surface of the heat storage layer faces outward. In this case, the metal layer of the conveyor belt 8 conducts heat not only to the heat roller 4 but also to the heat storage layer by appropriate heat conduction. Further, the heat storage layer retains heat to keep the recording medium 1 in contact therewith.

Reference numeral 11 denotes a back platen roller which is provided so as to face the heat roller 4 and nips and conveys the recording medium 1, and is rotationally driven by a driving means (motor or the like) not shown. Reference numeral 12 is an endless belt having the same width as the conveyor belt 8 having a rubber surface, and the back platen roller 11 and the conveyor rollers 13 and 14 are arranged so as to face the conveyor belt 8.
It has been passed over between. Back platen roller 11
The heat roller 4 and the heat roller 4 are provided at a distance narrower than the thickness of the recording medium 1. By doing so, the platen roller 11 is not unnecessarily heated when the recording medium 1 is not present, and the life of the platen roller 11 is not impaired.

The conveyor belt 8 and the conveyor belt 12 form a conveyor path 15 for the recording medium 1, and are provided at intervals in the area where the conveyor path 15 is formed with a distance narrower than the thickness of the recording medium 1. There is.

Reference numeral 16 is a tungsten lamp having a reflecting mirror as a heating means, which heats the conveyor belt 8 while keeping it warm, and is driven by a tungsten lamp control circuit (not shown). The temperature sensor 17 as a temperature detecting means detects the temperature near the exit of the conveyance path 15 by the conveyance belt 8 and the conveyance belt 12, and sends the output to a tungsten lamp control circuit (not shown). The tungsten lamp control circuit controls the temperature of the tungsten lamp 16 to a predetermined temperature according to the output signal of the temperature sensor 17.

Reference numeral 18 denotes a thermal head as a thermal recording means, which is installed in the vicinity of the exit of the conveying path 15 and, for example, a thermal head having a heating element density of 8 dots / mm is used. The thermal head 18 is drive-controlled by a thermal head drive circuit (not shown). Reference numeral 19 denotes a back platen roller which is provided opposite to the thermal head 18 and holds and conveys the recording medium 1. The back platen roller 19 is rotationally driven by a driving unit (motor or the like) not shown.

FIG. 2 schematically shows the structure of the recording medium 1. That is, the base material 21 is made of, for example, polyethylene terephthalate having a thickness of 188 μm,
The thickness of the reflective film 22 is about 0.1 μm on the one surface.
m vapor-deposited aluminum film, a reversible transparent state and a cloudy state due to heat as the recording film 23, a thermoreversible recording film having a thickness of about 5 μm, and a protective film 24 having a thickness of about 2 μm are sequentially laminated. It is provided. The recording film 23 is, for example, about 60
A recording material is used which is in a transparent state at a temperature of 90 ° C to 90 ° C and is saturated at a temperature of about 110 ° C or higher to become a cloudy state.

FIG. 3 schematically shows an electric circuit of the visible image recording apparatus according to the first embodiment constructed as described above. In other words, the CPU (Central Processing Unit) 31 that controls the overall
ROM (read only memory) 32 for storing the control program of 31 and various fixed data, RAM (random access memory) 33 for storing various data, C
The heat roller temperature control circuit 34 for controlling the temperature of the heat roller 4 according to the instruction of the PU 31 and the output signal of the temperature sensor 7, the conveyance drive circuit 35, the instruction of the CPU 31, and the output signal of the temperature sensor 17 are used. A tungsten lamp control circuit 36 for driving and controlling the tungsten lamp 16 and a thermal head driving circuit 37 for driving and controlling the thermal head 18 are respectively connected.

In the transport drive circuit 35, a drive motor 38 for rotationally driving the heat roller 4, a drive motor 39 for rotationally driving the pair of supply rollers 2, 3, and the back platen rollers 11, 19 are rotationally driven. Drive motor 4
0 and 41 are respectively connected.

Next, the operation of the visible image recording apparatus according to the first embodiment having the above structure will be described. When the main power source (not shown) of the apparatus is turned on, the heat roller temperature control circuit 34 supplies power to the heat generating lamp 6 of the heat roller 4 until the temperature reaches a preset temperature according to an instruction from the CPU 31. The surface temperature of the heat roller 4 is detected by the temperature sensor 7, and its output is fed back to the heat roller temperature control circuit 34. When the surface temperature of the heat roller 4 reaches a predetermined temperature, the CPU
The power supply is stopped by the instruction of 31, and when the decrease of the surface temperature is detected by the output of the temperature sensor 7, the power supply is restarted.

In this way, the temperature of the heat roller 4 is controlled so as to maintain a predetermined temperature. In this embodiment, in order to raise the temperature of the recording film 23 of the recording medium 1 to the clearing temperature,
The surface temperature of the heat roller 4 is set to 150 ° C., for example. The surface temperature of the heat roller 4 is the same as that of the recording medium 1.
It is set to an appropriate value depending on the transport speed and the transparentization temperature of the recording film 23 of the recording medium 1.

In this case, the conveyor belt 12 facing the heat roller 4 is also heated by the radiant heat from the heat roller 4. That is, in this apparatus, the recording medium 1 is kept warm from both sides.

Before the power supply to the heat roller 4 is started,
The conveyance drive circuit 35 operates according to an instruction from the CPU 31, whereby the supply roller pairs 2 and 3, the heat roller 4, and the back platen rollers 11 and 19 are driven.

The conveyor belt 8 is heated by the heat roller 4 and its temperature gradually rises. However, since the parts other than the part in contact with the heat roller 4 are allowed to cool, the temperature does not rise significantly. The surface temperature inside the conveyor belt 8 is detected by the temperature sensor 17 and fed back to the tungsten lamp control circuit 36.

The tungsten lamp control circuit 36 has a CP
According to the instruction of U31, when the surface temperature is 30 ° C. or less, the tungsten lamp 16 is supplied with power and is turned on. When the tungsten lamp 16 is turned on, the conveyor belt 8 in the area of the conveyor path 15 corresponding to the tungsten lamp 16 is heated.

When the temperature sensor 17 detects that the temperature of the conveyor belt 8 near the exit side of the conveyor path 15 has reached 30 ° C. or higher, the CPU 31 instructs the power supply to the tungsten lamp 16 to be stopped. It Then, when it is detected again that the temperature becomes 30 ° C. or lower, the above operation is repeated.

In the region of the conveyor belt 8 forming the conveyor path 15, the temperature of the conveyor belt 8 is cooled to the maximum temperature on the inlet side of the conveyor path 15 heated by the heat roller 4 and as it moves to the outlet side. Therefore, the temperature decreases toward the exit side. Further, due to the control described above, the temperature of the conveyor belt 8 on the exit side of the conveyor path 15 does not fall below 30 ° C.

In this state, in accordance with an instruction from the CPU 31, the recording medium 1 on which a cloudy image (visible image) is recorded by the supply roller pairs 2 and 3 which are driven by the transport drive circuit 35 at a transport speed of, for example, 50 mm / s. Are supplied toward the heat roller 4. The heat roller 4 heats the recording film 23 of the recording medium 1 via the conveyor belt 8. By this heating, the temperature of the recording film 23 is raised to a temperature at which it becomes transparent.

The recording medium 1 heated by the heat roller 4 and released from the sandwiched state between the heat roller 4 and the back platen roller 11 is the transport path 1 sandwiched by the transport belts 8 and 12.
5 is transported. In the process of this conveyance, the temperature of the recording film 23 of the recording medium 1 is lowered, but since the conveyance belt 8 is kept warm, heat dissipation from the recording medium 1 is suppressed.
Therefore, the temperature drop of the recording film 23 of the recording medium 1 becomes gentle. Further, since the temperature of the conveyor belt 8 near the exit of the conveyor path 15 does not fall below 30 ° C., the temperature of the recording film 23 does not fall below 30 ° C.

The cloudy image recorded on the recording film 23 of the recording medium 1 is surely discharged at the exit of the transport path 15 by heating by the heat roller 4 and gradual cooling by the heat retaining effect of the transport belt 8 at the transport path 15. Have been erased.

The recording medium 1 from which the cloudy image has been erased in this manner is then sent to the thermal head 18. At this time, the thermal head drive circuit 37 driven by an instruction from the CPU 31 heats the thermal head 18. A new image is recorded by driving a body (not shown) according to the recording signal.

Now, the visible image erasing device according to this embodiment will be described. As a comparative example, for example, the conveying belts 8 and 12, the tungsten lamp 16, and the recording unit of the thermal head 18 are removed from the visible image recording apparatus shown in FIG. 1, and the conveying belts 8 and 12 are simply conveyed. A visible image erasing device provided with a roller is used. Using such a visible image erasing device (comparative example) and the visible image erasing device (present embodiment) in which the recording portion of the thermal head 18 is removed from the visible image recording device shown in FIG. The recorded image was erased by changing the temperature.

FIG. 4 shows the relationship between the environmental temperature and the erasing rate at that time. The erasing rate is a percentage of the reflection density after erasing divided by the background density. In the figure, the crosses are comparative examples
The ∘ mark indicates the value of the visible image erasing device according to this embodiment. FIG.
As is apparent from the above, in the visible image erasing device of the comparative example, 1
In a low temperature environment of 5 ° C. or lower, the temperature drop rate after erasing and heating becomes faster, so the erasing rate decreases even if the temperature of the recording film 23 of the recording medium 1 is raised to a temperature at which erasing is possible. On the other hand, in the visible image erasing apparatus according to the present embodiment, even after the erasing and heating, due to the heat retaining effect of the conveyor belt 8, even in a low temperature environment, the temperature is almost 10
An erase rate of 0% is obtained.

Next, the second embodiment will be described. FIG. 6 schematically shows a configuration of a visible image recording device to which the visible image erasing device according to the second embodiment is applied. The same parts as those in FIG. 1 will be described with the same reference numerals.

In FIG. 6, the recording medium 1 is supplied and conveyed by a pair of supplying rollers 2 and 3, and a plurality of conveying rollers 51,
Is carried to the thermal head 18. A first planar heater 52 and a second planar heater 53 as heating means are sequentially arranged above the transport rollers 51, ... In the transport direction of the recording medium 1. In this case, the transport rollers 51, ... Extend the recording medium 1 to the first planar heater 52 and the second planar heater 53.
The sheet is conveyed while being pressed with a predetermined pressure.

The pair of supply rollers 2 and 3, the conveying roller 5
The back platen rollers 19 are driven and controlled by a driving unit (not shown) so as to convey the recording medium 1 at a constant speed.

Further, the transport rollers 51, ..., The first planar heater 52, the second planar heater 53, and a planar heater control circuit described later constitute a heat erasing means.
FIG. 7 schematically shows the configurations of the first planar heater 52 and the second planar heater 53. That is,
The planar heaters 52 and 53 are, for example, a nichrome wire (Ni
The heat generating resistance wires 54 and 55 in which a heat generating wire such as Cr) is coated with an electric insulating material are arranged in a meandering pattern as shown in the figure, and together with temperature sensors (for example, thermistors) 56 and 57 as temperature detecting means. It is sandwiched between metal plates 58 and 59 such as aluminum having good thermal conductivity, and a silicon rubber film (not shown) having high heat resistance is laminated on the contact surface with the recording medium 1 to improve contact. It is configured.

The power supply terminals of the heating resistance wires 54 and 55 and the signal output terminals of the thermistors 56 and 57 are connected to a planar heater control circuit described later by harnesses not shown. The heating resistance wire 54 of the first planar heater 52 is the heating resistance wire 5 of the second planar heater 53.
It is formed with a density higher than 5, so that a large heat output can be obtained.

Further, the recording medium 1 of the first planar heater 52
Is shorter than the second planar heater 53 in the carrying direction. Specifically, the first planar heater 52 is 20 mm, and the second planar heater 53 is 40 mm.

FIG. 8 schematically shows an electric circuit of the visible image recording apparatus according to the second embodiment constructed as described above. The same parts as those in FIG. 3 will be described with the same reference numerals.

That is, the CPU 31 has a ROM 32,
RAM 33, CPU 31 command and the temperature sensor 5
6, a planar heater control circuit 61 for controlling the temperature of the first planar heater 52 in accordance with the output signal of the CPU 6, a command from the CPU 31, and the second signal in response to the output signal of the temperature sensor 57.
The planar heater control circuit 62 for controlling the temperature of the planar heater 53, the conveyance drive circuit 35, and the thermal head drive circuit 37 are connected to each other.

In the transport drive circuit 35, a drive motor 39 that rotationally drives the supply roller pairs 2 and 3, a drive motor 41 that rotationally drives the back platen roller 19, and the transport roller 51 are rotationally driven. The drive motors 63 are respectively connected.

Next, the operation of the visible image recording apparatus according to the second embodiment having the above structure will be described. When the main power source (not shown) of this device is turned on, the heating resistance wires of the sheet heater control circuits 61 and 62 to the sheet heaters 52 and 53 are heated to a preset temperature according to an instruction from the CPU 31. Power is supplied to 54 and 55, respectively. The temperature of the first planar heater 52 is detected by the temperature sensor 56, and the temperature of the second planar heater 53 is detected by the temperature sensor 57.
Are detected by the sensor and are fed back to the planar heater control circuits 61 and 62, respectively.

When the temperature of the first sheet heater 52 reaches, for example, 90 ° C., the power supply is stopped according to the instruction from the CPU 31. When the temperature of the second planar heater 53 reaches, for example, 40 ° C., the power supply is stopped according to the instruction from the CPU 31. When the decrease in temperature is detected by the outputs of the temperature sensors 56 and 57, power supply is restarted.

In this way, the temperatures of the first and second sheet heaters 52, 53 are controlled so as to maintain a predetermined temperature. The temperatures of the first and second planar heaters 52 and 53 are set to appropriate values according to the transport speed of the recording medium 1 and the transparentization temperature of the recording film 23 of the recording medium 1.

When a sensor (not shown) detects that the recording medium 1 has been loaded into the apparatus, the feeding drive circuit 35 operates according to an instruction from the CPU 31, whereby the supply roller pairs 2 and 3, the feeding roller 51, Also, the back platen roller 19 is driven.

In this state, in accordance with an instruction from the CPU 31, the recording medium 1 on which a cloudy image (visible image) is recorded by the supply roller pairs 2 and 3 driven by the transport drive circuit 35 at a transport speed of, for example, 50 mm / s. Are supplied toward the first planar heater 52. The recording medium 1 is pressed against the first planar heater 52 by the transport roller 51, and the first planar heater 52 heats the recording film 23 of the recording medium 1. By this heating, the temperature of the recording film 23 is raised to a temperature at which it becomes transparent.

The recording medium 1 heated by the first planar heater 52 is further continuously transported by the transport roller 51 driven by the transport drive circuit 35 and supplied to the second planar heater 53. The recording medium 1 is kept warm by the second planar heater 53 kept at 40 ° C., and the temperature of the visible image forming surface of the recording medium 1 is kept until the recording medium 1 passes through the second planar heater 53. Keep the temperature around 40 ° C.

The white turbid image recorded on the recording film 23 of the recording medium 1 is heated by the first planar heater 52 and gradually cooled by the heat retaining effect of the second planar heater 53, so that the second surface is cooled. It is surely erased when the heater 53 is released.

The recording medium 1 from which the cloudy image has been erased in this manner is then sent to the thermal head 18. At this time, the thermal head drive circuit 37 driven by an instruction from the CPU 31 heats the thermal head 18. A new image is recorded by driving a body (not shown) according to the recording signal.

Next, the third embodiment will be described. FIG. 9 schematically shows a configuration of a visible image recording device to which the visible image erasing device according to the third embodiment is applied. The same parts as those in FIG. 1 will be described with the same reference numerals.

In FIG. 9, the recording medium 1 is supplied and conveyed by the supply roller pairs 2 and 3, and a plurality of conveyance roller pairs 7 are provided.
1, ... and the transport guide 72, the thermal head 1
It is designed to be transported to 8. Transport roller pair 71,
A planar heater 73 as a heating means is arranged above the. The planar heater 73 is installed so that the distance from the upstream side to the downstream side of the transport guide 72 with respect to the transport direction of the recording medium 1 becomes wider. In this case, the recording medium 1 and the planar heater 73 are set so as not to come into contact with each other in the section of the transport guide 72. On the upstream side, a space is set so that the recording medium 1 and the planar heater 73 are in close proximity to each other, and on the downstream side, the recording medium 1 is heated by radiant heat on the upstream side to increase the temperature. The intervals are set so that a temperature of 1/2 is obtained.

A temperature sensor 74 as a temperature detecting means for detecting the environmental temperature is provided in the vicinity of the supply roller pair 2, 3.
Is installed. The pair of supply rollers 2 and 3, the pair of transport rollers 71, ..., And the back platen roller 19
Is driven and controlled by a driving unit (not shown) so that the recording medium 1 is conveyed at a constant speed.

Further, the pair of conveying rollers 71, ..., The planar heater 73, and the planar heater control circuit described later constitute a heat erasing means. FIG. 10 shows the planar heater 7
3 schematically shows the configuration of No. 3. That is, in the planar heater 73, for example, a heating resistance wire 75 in which a heating wire such as a nichrome wire (NiCr) is covered with an electric insulating material is arranged in a meandering pattern as shown in the figure.
Along with a temperature sensor (for example, a thermistor) 76 as a temperature detecting means, it is sandwiched by a metal plate 77 such as aluminum having a good thermal conductivity, and further, it has high heat resistance in order to improve the contact with the contact surface with the recording medium 1. It is configured by laminating silicon rubber films (not shown).

The power supply terminal of the heating resistance wire 75 and the signal output terminal of the thermistor 76 are connected to a planar heater control circuit described later by harnesses not shown. The heating resistance wire 75 of the planar heater 73 is shown in FIG.
Like the heating resistance wire 54 shown in FIG.
Further, the length of the planar heater 73 in the transport direction of the recording medium 1 is set to be substantially equal to that of the transport guide 72.

FIG. 11 schematically shows an electric circuit of the visible image recording apparatus according to the third embodiment constructed as described above. The same parts as those in FIG. 3 will be described with the same reference numerals.

That is, the CPU 31 has a ROM 32,
RAM 33, CPU 31 command and the temperature sensor 7
A sheet heater control circuit 81 for controlling the temperature of the sheet heater 73 in accordance with the output signals of 4, 76 and the transport drive circuit 3.
5 and the thermal head drive circuit 37 are connected to each other.

The transport drive circuit 35 includes a drive motor 39 for rotationally driving the supply roller pairs 2 and 3, a drive motor 41 for rotationally driving the back platen roller 19, and a rotary drive for the transport roller pair 71. The drive motors 82 are connected to each other.

Next, the operation of the visible image recording apparatus according to the third embodiment having the above structure will be described. When the main power source (not shown) of this device is turned on, the CPU 31 gives an instruction to set the temperature to a temperature preset in a one-to-one relationship with the environmental temperature based on the output signal from the temperature sensor 74 for detecting the environmental temperature. Until this happens, power is supplied from the planar heater control circuit 81 to the heating resistance wire 75 of the planar heater 73.

In this case, the set temperature is set to a temperature at which the recording film 23 can be heated to a temperature at which the image recorded on the recording film 23 of the recording medium 1 can be erased (made transparent) at each environmental temperature. In this embodiment, since the transparentizing temperature of the recording film 23 is 60 ° C. to 90 ° C., the heat generation temperature of the planar heater 73 is set to about 150 ° C.

The temperature of the sheet heater 73 is measured by the temperature sensor 76.
Detected by the sheet heater control circuit 81.
Be fed back to. Then, when the temperature of the planar heater 73 reaches a predetermined temperature, power supply is stopped according to an instruction from the CPU 31. When the decrease in temperature is detected by the output of the temperature sensor 76, power supply is started again.

In this way, the temperature of the planar heater 73 is controlled so as to maintain a predetermined temperature. The temperature of the planar heater 73 is set to an appropriate value depending on the conveyance speed of the recording medium 1 and the transparentization temperature of the recording film 23 of the recording medium 1 in addition to the environmental temperature.

When a sensor (not shown) detects that the recording medium 1 has been loaded into the apparatus, the feeding drive circuit 35 operates according to an instruction from the CPU 31 to supply the feeding roller pairs 2 and 3 and the feeding roller pair 71. , And the back platen roller 19 are respectively driven.

In this state, in accordance with an instruction from the CPU 31, the recording medium 1 on which a cloudy image (visible image) is recorded by the supply roller pairs 2 and 3 driven by the transport drive circuit 35 at a transport speed of, for example, 50 mm / s. Are supplied toward the sheet heater 73. The recording medium 1 is transported by the transport roller pair 71 along the transport guide 72. At this time, the recording film 23 of the recording medium 1 is heated by heating from the planar heater 73 on the upstream side in the transport direction where the planar heater 73 is close to the recording medium 1. By this heating, the recording film 23
Is raised to a temperature at which it becomes transparent.

Recording medium 1 heated on the upstream side in the transport direction
Are further continuously transported by the transport roller pair 71 driven by the transport drive circuit 35. At this time, since the clearance between the planar heater 73 and the recording medium 1 increases from the upstream side to the downstream side in the transport direction, the temperature of the recording film 23 of the recording medium 1 does not become higher than the clearing temperature. Although the temperature of the recording film 23 decreases, the radiant heat from the planar heater 73 causes the temperature to decrease gradually.
As a result, the temperature of the recording film 23 of the recording medium 1 is maintained at about 30 ° C. to 40 ° C. even near the outlet of the planar heater 73.

The cloudy image recorded on the recording film 23 of the recording medium 1 is surely erased by the surface heater 73 by the heating by the surface heater 73 and the gradual cooling due to the heat retaining effect.

The recording medium 1 from which the cloudy image has been erased in this manner is then sent to the thermal head 18. At this time, the thermal head drive circuit 37 driven by an instruction from the CPU 31 heats the thermal head 18. A new image is recorded by driving a body (not shown) according to the recording signal.

As described above, according to the above embodiment,
After erasing and heating the recording medium, the visible image on the recording medium is erased as in the past by heating the visible surface of the recording medium at a temperature below the temperature at which the visible image can be erased for a time longer than the erase heating time. The visible image of the recording medium conveyed at high speed can be surely erased without changing the conveying speed of the recording medium between time and recording.

Further, since the recording medium is kept warm under a constant condition regardless of the environmental temperature, the visible image can be surely erased even if the environmental temperature changes. Furthermore, according to the first embodiment, the temperature of the recording medium is kept warm from both sides, so that the temperature drop becomes more gradual, and the visible image can be surely erased.

Further, according to the second embodiment, it is guaranteed that the temperature is kept constant in the heat retention region irrespective of the ambient temperature, and reliable erasure can be performed regardless of the ambient temperature. In addition, since the heating is performed without being moved by the planar heater that is fixed, high reliability can be obtained.

Further, according to the third embodiment, since the erasing heating temperature and the heat retaining temperature which do not change even if the environmental temperature changes, the stable visible image erasing is always performed regardless of the change of the environmental temperature. Can be done.

In the above embodiment, the white turbid state of the recording film of the recording medium was used as the recorded image, but the white turbid state was set as the erased state, and the recording medium was controlled so as to be in the white turbidity temperature range during the erasing, and recorded during recording. If the medium is controlled so as to be in the transparentization temperature range, it is possible to make the transparent state a recorded image.

The recording material to which the present invention can be applied is not limited to the material of the above-mentioned embodiment, and for example, a recording material using a leuco dye as a color-forming source which reversibly changes color tone only by controlling thermal energy. Can also be adapted.

[0084]

As described above in detail, according to the present invention, the visible image of the recording medium which is conveyed at a high speed can be surely obtained without changing the conveying speed of the recording medium between the time of erasing the visible image and the time of recording. It is possible to provide a visible image erasing method, a visible image erasing device, and a visible image recording device that can be erased without difficulty and that can reliably erase a visible image even when the environmental temperature changes.

[Brief description of drawings]

FIG. 1 is a configuration diagram schematically showing a configuration of a visible image recording device to which a visible image erasing device according to a first embodiment of the present invention is applied.

FIG. 2 is a vertical cross-sectional side view schematically showing the configuration of the recording medium in the example.

FIG. 3 is a block diagram schematically showing a configuration of an electric circuit of the embodiment.

FIG. 4 is a view for explaining the operational effect of the visible image erasing device in the embodiment.

FIG. 5 is a diagram for explaining the knowledge on which the present invention is based.

FIG. 6 is a configuration diagram schematically showing a configuration of a visible image recording device to which a visible image erasing device according to a second embodiment of the present invention is applied.

FIG. 7 is a plan view schematically showing the configuration of a planar heater in the example.

FIG. 8 is a block diagram schematically showing the configuration of an electric circuit of the embodiment.

FIG. 9 is a configuration diagram schematically showing a configuration of a visible image recording device to which a visible image erasing device according to a third embodiment of the present invention is applied.

FIG. 10 is a plan view schematically showing the configuration of the planar heater in the example.

FIG. 11 is a block diagram schematically showing the configuration of an electric circuit of the embodiment.

[Explanation of symbols]

1 ... Recording medium, 2, 3 ... Supply roller pair, 4 ... Heat roller (heat erasing means), 7, 17 ... Temperature sensor,
8, 12 ... Transport belt (transport means), 11, 19 ...
Back platen roller, 15 ... Transport path, 16 ... Tungsten lamp (heating means), 18 ... Thermal head (thermal recording means), 31 ... CPU, 32 ... R0M, 3
3 ... RAM, 34 ... Heat roller temperature control circuit, 3
5 ... Transport drive circuit, 36 ... Tungsten lamp control circuit, 37 ... Thermal head drive circuit, 51 ... Transport roller, 52, 53 ... Sheet heater (heating means), 6
1, 62 ... Planar heater control circuit, 71 ... Transport roller pair, 72 ... Transport guide, 73 ... Planar heater (heating means), 74 ... Temperature sensor, 81 ... Planar heater control circuit.

Claims (5)

[Claims] 1. A thermal history of different temperatures indicates two states of recording and erasing of a visible image, and a thermal erasing means can be used to erase the visible image on a recording medium to be conveyed. A visual image erasing method, wherein erasing heating for erasing a visible image is performed on a visible image recording surface of the recording medium for a predetermined time, and after the erasing heating, the visible image recording surface of the recording medium. The method for erasing a visible image according to claim 1, wherein the heating is carried out at a temperature equal to or lower than a temperature at which the visible image can be erased, for a time longer than the erasing heating time. 2. A first transporting means for transporting a recording medium showing two states of recording and erasing a visible image by thermal histories of different temperatures, and the recording medium transported by the first transporting means. Thermal erasing means for erasing the visible image by erasing and heating the visible image recording surface, and the recording medium from which the visible image has been erased by the thermal erasing means has belt-shaped conveying members on both sides. Second conveying means for nipping and conveying the entire surface, and at least a visible image recording surface of the recording medium conveyed by the second conveying means is kept warm via a belt-like conveying member of the second conveying means. A visible image erasing device comprising: a heating unit for heating. 3. Conveying means for conveying a recording medium showing two states of recording and erasing a visible image by thermal history of different temperatures, and a visible image recording surface of the recording medium conveyed by the conveying means. The recording medium is composed of sheet heating elements that are arranged so as to face each other and have a density that is coarse so that the heating temperature decreases from the upstream side to the downstream side of the recording medium in the transport direction. After erasing and heating the visual image recording surface, the visible image recording surface is gradually cooled while maintaining the temperature range below the visible image erasing temperature and above the environmental temperature. A visible image erasing device characterized by being provided. 4. Conveying means for conveying a recording medium showing two states of recording and erasing a visible image by thermal history of different temperatures, and a visible image recording surface of the recording medium conveyed by the conveying means. Visible image recording on the recording medium, which is composed of planar heating elements that face each other and are arranged so that the distance from the recording medium to the downstream side becomes wider from the upstream side to the downstream side. A heating means for gradually cooling the surface of the visible image after the erasing and heating of the surface, while maintaining the visible image recording surface at a temperature below the erasing temperature of the visible image and above the ambient temperature. A visible image erasing device characterized by. 5. Conveying means for conveying a recording medium showing two states of recording and erasing a visible image by thermal history of different temperatures, and a visible image recording surface of the recording medium conveyed by the conveying means. On the other hand, a thermal erasing means for erasing a visible image by performing erasing heating, and a temperature below the temperature at which the visible image recording surface of the recording medium can erase the visible image after the erasing and heating by the thermal erasing means. And a heat recording means for recording a visible image on the visible image recording surface of the recording medium after the heat retention heating by the heating means. A visible image recording device characterized in that