DE60201214T2 - Apparatus for printing, erasing, and rewriting visible images on thermochromic recording material - Google Patents

Description

BACKGROUND THE INVENTION

1 , Field of the invention

The The present invention relates to repeatable printing and erasing visible image on a thermochromic material, with a dark Color through the application of heat reversibly changed to white.

2. relatives technology

paper copies (Hardcopy) are generally made by adding a colorant (eg ink or toner) from the outside acting on a recording medium, such as plain paper, to make pictures. Alternatively, a semi-permanent image on a heat-sensitive Recording paper produced by applying heat energy, to form a visible image.

In recent years is the consumption of paper and other recording media in the ever stronger Distribution of photocopiers and fax machines and partly because of the increasing amount of information available about computers downloaded from networks, has become bigger and bigger. The huge paper consumption is the subject of public Interest, as it is the destruction of forests and an increase of Waste causes. To overcome these problems are reusable thermochromic recording materials in which recorded deleted visible images can be into the center of attention.

JPA (Kokai) 55-154198 and EP 0 014 826 A reveal z. A recording medium using the change by light scattering of a polymer in which organic crystal grains of low molecular weight are dispersed. In this medium, two different states, ie a transparent state and an opaque state, are generated in a reversible manner. This medium is already practically used as an indication on magnetic cards. However, this medium is unsuitable for ordinary hardcopy because white images are formed on a black or blue background or on a light-reflecting background (such as a vapor-deposited aluminum film).

JPA 5-124360 ( EP 492 628 A ) discloses a thermochromic recording medium using a leuco dye in a thermochromic recording layer. The leuco dye assumes two distinct states by heating or with different heating cycles, ie, a colored state and a colorless state, and allows a monochrome or grayscale print image to be formed on a white background. When the leuco dye recording layer is heated, exceeding a first temperature T1, staining suddenly begins at a second temperature T2 (T2> T1). Then, by rapidly cooling the recording layer, the printed state (or the colored state) is fixed. To erase the printed image, the recording medium is reheated. The print image suddenly loses color near the first temperature T1, and the colorless state (or the erased state) is fixed at a temperature between T1 and T2.

The 1A illustrates the rewritable printing apparatus disclosed in JPA (Kokai) 5-124360 100 , which is suitable for the above-described thermochromic recording medium, and the 1B illustrates the thermal head 121 and the environment of the extinguishing unit 120 , The printing device 100 has a deletion unit 120 and a recording unit 130 in this order along the transport route. The delete unit 120 has a deletion thermal head 121 and a pressure adjusting mechanism 123 to the erase thermal head 121 against a pressure roller 122 to press. The delete unit 130 has a recording thermal head 131 and a pressure adjusting mechanism 133 to the recording thermal head 131 against a pressure roller 132 to press.

The thermochromic recording medium 101 gets into the guide shaft 111 inserted and through the sensor 112 detected. The recorded recording medium 101 gets through the pressure rollers 122 and 132 guided in the direction of the arrows. During transport, those in the thermochromic layer of the recording medium become 101 Made visible images by the erase thermal head 121 the extinguishing unit 120 deleted. The deleted recording medium 101 gets along the guide 113 located on the outlet side of the erase thermal head 121 is arranged, transported horizontally. The recording medium 101 then passes between the pressure roller 132 and the recording thermal head 131 the recording unit 130 and is subjected to a new recording operation to print letters or drawings on the erased thermochromic layer. The recording medium 101 eventually gets into the tray 114 pushed out.

As in 1B is illustrated has the erase thermal head 121 One Base 125 and a belt-shaped heater 124 based on that 125 is provided. The heater 124 is the pressure roller 122 facing and brings heat to the (not shown) thermochromic layer of the up drawing medium 101 to clear the image when the recording medium 101 through the heater 124 and the pressure roller 122 runs.

JPA (Kokai) 2000-132648 and EP 1 004 978 A disclose a similar type of rewritable printing device that can reprint cards. In this apparatus, a card having a thermochromic layer moves in a straight line along the horizontal transport path during erasing and recording.

JPA (Kokai) 6-191116 discloses an erasing device, the recording media continuously and successively regardless of the type of paper respectively can and can reduce the time it takes to reprint images is required. If a reusable bow is used the sheet is passed between a heating roller and a rubber roller to to erase the information printed on the sheet by writing during the Transports heat acting on the bow. When heat sensitive Recording paper is used, a heat-insulating aperture under The heating roller is used to absorb the action of heat to block the thermochromic recording paper. JPA 11-193164 discloses a heat-insulating Structure provided on a stacking unit of the ejected sheets is the increase in temperature in the recording device reduce, this device is not of a thermochromic Type is.

The above-described erasing and recording devices have only limited use for rewriting magnetic cards or IC cards, and they are practically unusable for rewriting documents printed on standard size paper. The surface of a thermochromic recording medium 101 with a normal card size (55 mm × 85 mm) can be uniformly heated to a quenching temperature. When the thermochromic recording medium 101 however, when enlarged to standard A4 size (210mm x 297mm) for use with ordinary documents, uniform erasing and recording over the entire surface area can not be achieved.

One reason for the inapplicability of normal size documents is that the entire surface can not be heated sufficiently to a suitable temperature range. When the thermochromic layer of the recording medium 101 is formed from a leuco dye, the acceptable variance of the quenching temperature is about 10 ° C to 20 ° C, which is a relatively narrow control range. In a thermochromic recording medium 101 A4 size, the distribution of the surface temperature varies greatly and some portions of the medium can not reach the erasing temperature, leaving some of the images undeleted. On the other hand, some portions may be heated beyond the upper limit of the extinguishing temperature, causing a slight coloration of the thermochromic layer.

Another problem in the known rewritable printing apparatus is with the transport of the thermochromic recording medium 101 connected in the device. Thus, the thermochromic recording medium 101 not only the size but also the thickness, which is the same thickness as that of the paper normally used for photocopiers or facsimile machines in offices or private areas, must be standard. The thickness of the plain paper is generally about 115 μm. Accordingly, an experiment was carried out using a thermochromic recording paper 101 having a base having a thickness of 115 μm, this recording medium being used in the erasure and recording processes in the conventional rewritable printing apparatus 10 , which is disclosed in JPA 5-124360.

The erasing and coloring processes are carried out normally when the straight-line transport speed of the recording medium 101 is set to a relatively low value. However, if the transport speed increases to the general transport speed of a photocopier or a facsimile machine, printing errors will occur. Such errors are the result of insufficient heating time at an erasing temperature and insufficient cooling time before re-printing using the recording thermal head. The thermochromic recording medium 101 reaches the recording thermal head 131 before the surface is sufficiently cooled and the re-printing is carried out while the temperature of the thermochromic recording medium 101 still relatively high. Therefore, coolant and means for controlling the extinguishing temperature are required.

When the erasing and recording are suitably carried out at a low transport speed, waves also appear 115 on the surface of the thermochromic recording medium 101 , as in 1C is shown. The waves 115 Appear regardless of the transport speed of the medium and they are noticeable when a recording medium 101 A4 size is used. such waves 115 prevent good contact between the recording medium 101 and the erase thermal head 121 or with the recording thermal head 131 and result in poor re-printed images due to insufficient erasure and poor uniformity of color density.

therefore can the conventional ones rewritable printing devices no stable erase operations and uniform Guarantee newly printed images.

In addition, shows US 5,517,228 A an extinguishing device. The image data can be deleted by the deletion element 26 be deleted, the arc then over the Bogenauswurfdurchlass 22 and pickup rollers 13 can be ejected.

SUMMARY THE INVENTION

The The present invention therefore serves an erasing device to create a thermochromic recording medium with a normal Paper size (eg Size A4) and the print images even at a higher transport speed can delete satisfactorily.

The the present invention also serves to a rewritable device to turn on the reliable operations to delete and Reprinting guaranteed, without unwanted waves on the thermochromic Effect recording medium.

A extinguishing device heats a thermochromic recording medium to a prescribed erasing temperature or at a prescribed extinguishing temperature to one on the thermochromic recording medium to erase printed printed image. The thermochromic recording medium has multiple layers on a base made of different materials that have a thermochromic layer contain. The extinguishing device also causes that the heated thermochromic recording medium cools while a Tensile stress exercised is to cause a wave formation or deformation of the thermochromic Prevent recording medium. Since the thermochromic recording medium contains different material layers, the different thermal Have expansion coefficients, deform or contract these layers are independent from each other, which is an undesirable Wave formation or curvature causes. By exercising a tensile stress on the thermochromic recording medium, that while the cooling process a delete (i.e., heating) may cause a wave or a vault be effectively prevented.

In An aspect of the invention is an erasing apparatus as claimed in claim 1 is created.

The Stress applying device is z. B. a curved surface the transport path containing the thermochromic recording medium along the curved surface transported to the outlet side.

Of the radius of curvature the curved surface is preferably equal to or less than 40 mm. The transport route can through a curved Guide, several rolls, a belt that runs around several rolls, one Air flow or other suitable means to be defined.

The Stress applying device is alternatively, an inclined transport path, which is at a prescribed Angle to the horizontal tends. In any case, the stress applying device has a cooling area, to cool the heated thermochromic recording medium.

In Another aspect of the invention is a rewritable Printing device, the above-described erasing device and an the outlet side of the extinguishing device Positioned recording unit contains created. The recording unit prints a new image on the deleted by the extinguishing device thermochromic Recording medium.

The Recording unit has a recording heater, the thermochromic recording medium to a second temperature heated that of the extinguishing temperature is different.

at This rewritable printing device will do this on the recovered thermochromic recording medium printed image satisfactory deleted, without waves forming or being damaged and therefore a new image can be taken on the erased thermochromic recording medium clearly printed.

In another proposal, which does not correspond to the claimed invention, there is provided an erasing device having a erasing condition control property. The erasing apparatus includes heating means for heating the thermochromic recording medium to an erasing temperature to erase an image printed on the thermochromic recording medium, printing means for thermochromic recording Pressing medium against the heating means, a first temperature sensor for detecting the temperature of the pressure means and deletion condition control means to determine based on the temperature of the pressure means a suitable for the thermochromic recording medium deletion condition.

The Erasing condition control means contain temperature adjustment means to the extinguishing temperature of the heating means determine on the basis of the detected temperature of the pressure medium, and Temperature control means to the temperature of the heating roller the extinguishing temperatures set by the temperature setting means to control and maintain.

The Erasing condition control means Also include transport speed selection means to the Transport speed of the thermochromic Aufzeich recording medium select on the basis of the temperature of the pressure roller, and transport control means, about the transport operation of the thermochromic recording medium at the chosen To control speed.

at this extinguishing device become the optimal extinguishing conditions selected based on the temperature of the pressure roller. As a result, the thermochromic Recording medium at the optimal transport speed the heating means and transported away from them and is at the optimum erasing temperature heated while it passes between the heating means and the pressure roller. As a result, can the images printed in the thermochromic recording medium over the entire area of the thermochromic recording medium can be cleared evenly, without that damages occur.

SUMMARY THE DRAWING

Further Objects, features and advantages of the invention will become more apparent from the following detailed description, when used in conjunction with the attached Drawing is read, wherein:

1A a conventional rewritable printing device is illustrated, 1B illustrates a conventional erasing apparatus used in the rewritable printing apparatus, and 1C Illustrates waves that occur on the thermochromic recording medium;

2 an example of the thermochromic recording medium is illustrated;

the 3A and 3B illustrate a change in the transport angle of the thermochromic recording medium after applying quenching heat;

4 illustrates the cooling of the heated recording medium while the recording medium is guided at a certain angle to the horizontal;

5 Temperature profiles of the recording medium illustrates that longitudinally

of in 4 transported transport is shown;

the 6A to 6D Illustrate examples of the erasing apparatus according to the first embodiment of the invention;

the 7A and 7B Illustrate examples of the erasing apparatus according to the second embodiment of the invention;

the 8A to 8D Illustrate examples of the erasing apparatus according to the third embodiment of the invention;

the 9A to 9G Illustrate examples of the rewritable printing apparatus according to the fourth embodiment of the invention;

the 10A and 10B Illustrate examples of the rewritable printing apparatus according to the fifth embodiment of the invention;

the 11A and 11B Illustrate examples of the vertical type extinguishing apparatus according to the sixth embodiment of the invention;

12 illustrates a modification of the vertical type extinguishing apparatus according to the sixth embodiment of the invention;

13 illustrates an example of the rewritable printing apparatus that can be used in a vertical type erasing apparatus according to the seventh embodiment of the invention; and

14 illustrates a modification of the rewritable printing apparatus according to the seventh embodiment of the invention;

15 another modification of the rewritable printing apparatus according to the seventh embodiment of the invention illustrated;

16A illustrate another modification of the rewritable printing apparatus light and 16B illustrates a curved guide used in the device of 16A is used according to the seventh embodiment of the invention;

17 an example of the rewritable printing apparatus having two sensors arranged at the beginning and at the end of the transport path between the erasing thermal head and the recording thermal head according to the eighth embodiment of the invention;

18 illustrates a modification of the rewritable printing apparatus according to the eighth embodiment of the invention;

19 Fig. 15 illustrates an operation for controlling the transportation of the thermochromic recording medium according to the eighth embodiment of the invention;

20 another modification of the rewritable printing apparatus according to the eighth embodiment of the invention illustrated;

the 21A and 21B Illustrate decolorization temperature characteristics of various types of thermochromic layers;

22A the chemical formulas of the developers illustrated and 22B illustrates the chemical formulas of leuco dyes used in the thermochromic layers of the 21A and 21B be used;

the 23A and 23B Illustrate experiments to obtain the relationship between the transport speed and the color intensity of the image remaining after erasure;

24 is a plot showing suitable quenching temperatures resulting from the experiments of 23A and 23B to be obtained;

25 Fig. 10 is a graph showing a change in the surface temperature of the pressure roller;

the 26A and 26B Illustrate examples of the erasing device and the 26C and 26D Examples of the rewritable printing apparatus which are incorporated in the 26A respectively. 26B shown extinguishing devices according to a first proposal, which does not correspond to the claimed invention use;

the 27A and 27B Illustrate examples of the erasing device and the 27C and 27D Examples of the rewritable printing apparatus which are incorporated in the 27A respectively. 27B shown extinguishing devices according to a second proposal, which does not correspond to the claimed invention use;

28A an example of the extinguishing device is illustrated and 28B An example of the rewritable printing apparatus illustrating the erasing apparatus of FIG 28A according to a third proposal which does not correspond to the claimed invention; and

29A an example of the erasing device according to a fourth proposal, which does not correspond to the claimed invention, illustrated and 29B FIG. 4 illustrates an example of the rewritable printing apparatus using the erasing apparatus similar to that shown in FIG 29B is similar to the shown erasing device.

PRECISE DESCRIPTION THE EMBODIMENTS

The Details of the invention will now be with reference to the accompanying drawings described.

2 illustrates an example of the thermochromic recording medium 1 , The thermochromic recording medium 1 owns a base 2 , a thermochromic layer 3 that over the top surface of the base 2 is formed, a first translucent protective layer 4 and a second translucent protective layer 5 , The bottom of the base 2 is with a backcoating layer 6 covered. The base 2 is z. Made of paper, composite paper or a resin such as polyethylene terephthalate (PET), and the thickness is in the range of 0.05 mm to 0.22 mm. The thickness of the thermochromic layer 3 is 8-9 μm and the thickness of the first translucent protective layer 4 , the second translucent protective layer 5 and the recoating layer 6 are each set to about 2 microns.

Simple paper used for photocopiers and fax machines in offices has a thickness of about 0.05 mm to 0.22 mm. If the thickness is less than 0.05 mm, the paper becomes slack, and over 0.22 mm, it is unsuitable for archiving. By determining the thickness of the thermochromic recording medium 1 on the thickness of plain paper, the thermochromic recording paper 1 be easily handled in the same way as plain paper. The mechanical characteristics (durability, bendability, etc.) of the thermochromic recording medium 1 are mainly through the base 2 Are defined.

The thermochromic layer 3 is made of a resin binder in which a leuco dye and a developer are dispersed. The leuco dye that is in the thermochromic layer 3 is a known dye starting material, such as a phthalide compound, an azaphtalide compound, a fluoran compound, a phenothiazine compound or a leucoauramine compound. The developer working in the thermochromic layer 3 is a compound containing a chemical formula (e.g., a phenol-type hydroxyl group, a carboxylic acid group, a phosphoric acid group, etc.) having developmental functions to cause the leuco-dye to make a coloration visible in its molecules. The developer also has a chemical formula to control compaction between molecules, e.g. A structure having a long-chain hydrocarbon group connected to a divalent group containing or not containing heteroatoms at the linking portion. The long-chain hydrocarbon group may itself contain a divalent group containing heteroatoms or an aromatic group. The developers disclosed in JPA 5-124360 can e.g. B. can be used as a developer.

The first and second translucent protective layer 4 . 5 and the recoating layer 6 are made of a thermosetting polymer and these layers are intended to increase the strength of the thermochromic recording medium 1 to be repeatedly subjected to the erasing operation and the recording operation. The upper surface of the thermochromic layer 3 must be protected in detail since the thermochromic recording medium 1 is heated in direct contact with the erasing thermal head and the recording thermal head. For this reason, in the in 2 shown example, the double protective layers 4 and 5 intended. However, a recording medium having a single translucent protective layer can be used. In this case, the thickness of the translucent protective layer may be larger. The recoating layer 6 can be omitted if the base 2 there is no paper. The recoating layer 6 prevents buckling when the paper base 2 due to the moisture absorbed by it expands or contracts.

• (A) Ein thermochromisches Aufzeichnungsmedium 101 wurde dem Lösch-Thermokopf 121 horizontal zugeführt und unter Verwendung der herkömmlichen Löschvorrichtung, die in 1A gezeigt ist, auf 100–160°C erhitzt. Das erhitzte thermochromische Aufzeichnungsmedium 101 wurde von dem Lösch-Thermokopf 121 geradlinig in horizontaler Richtung geführt.
• (B) Ein thermochromisches Aufzeichnungsmedium 1 wurde dem Lösch-Thermokopf 21 horizontal zugeführt und unter Verwendung einer Löschvorrichtung 10, die in 3A gezeigt ist, auf 100–160°C erhitzt. Das erhitzte thermochromische Aufzeichnungsmedium 1 wurde dann unter einem bestimmten Winkel zu der Horizontalen längs des Transportweges, der durch die Pfeile angegeben ist, schräg nach oben geführt. In diesem Fall wurden die Wellen 115 beträchtlich verringert und in Abhängigkeit von der Dicke des Mediums traten keine Wellen auf. Wenn der Winkel des Transportweges zu der Horizontalen auf 30° oder auf einen größeren Wert eingestellt wurde, traten keine Wellen auf, vorausgesetzt die Dicke der Basis 2 (die aus Papier oder PET hergestellt ist) des thermochromischen Aufzeichnungsmediums 1 betrugt 0,05 mm bis 0,22 mm.
• (C) Ein thermochromisches Aufzeichnungsmedium 1 wird dem Lösch-Thermokopf 21 horizontal zugeführt und auf 100–160°C erhitzt. Das erhitzte thermochromische Aufzeichnungsmedium 1 wird dann unter einem bestimmten Winkel zu der Horizontalen längs des Transportweges, der durch die Pfeile angegeben ist, durch die Schwerkraft natürlich nach unten geführt, wie in 3B veranschaulicht ist. In diesem Fall wurden die Wellen 115 beträchtlich verringert und in Abhängigkeit von dem Typ des Mediums traten keine Wellen auf. Wenn der Winkel des abwärtsfüh renden Transportweges zu der Horizontalen 30° betrug oder größer war, traten keine Wellen auf.
• (D) Ein thermochromisches Aufzeichnungsmedium 1 wurde dem Lösch-Thermokopf 21 horizontal zugeführt und auf 100–160°C erhitzt. Das erhitzte thermochromische Aufzeichnungsmedium 1 wurde längs des Transportweges unter der Steuerung einer Führung 13 entweder schräg nach oben oder schräg nach unten geführt, wie in den 3A oder 3B veranschaulicht ist. In diesem Fall wurde der Winkel des Transportweges durch die Führung 13 gesteuert und es traten keine Wellen auf, wenn der Winkel auf 30° oder mehr gesteuert wurde.
• (E) Ein thermochromisches Aufzeichnungsmedium 1 wurde dem Lösch-Thermo kopf 21 horizontal zugeführt und auf 100–160°C erhitzt. Das erhitzte thermochromische Aufzeichnungsmedium 1 wurde von dem Lösch-Thermokopf 21 durch eine Führung mit einer gekrümmten Oberfläche geführt. Dieses Experiment wurde ausgeführt, indem der Krümmungsradius der gekrümmten Oberfläche geändert wurde. Die Wellen, die an dem gelöschten thermochromischen Aufzeichnungsmedium 1 auftraten, waren stark verringert und insbesondere dann, wenn der Krümmungsradius auf 40 mm oder weniger eingestellt wurde, traten keine Wellen auf.
• (F) Ein thermochromisches Aufzeichnungsmedium 1 wurde dem Lösch-Thermokopf 21 horizontal zugeführt und auf 100–160°C erhitzt. Das erhitzte thermochromische Aufzeichnungsmedium wurde nach dem Lösch-Thermokopf 21 für eine bestimmte Strecke geradlinig geführt, wie in 4 veranschaulicht ist. Dann wurde die Transportrichtung des thermochromischen Aufzeichnungsmediums 1 unter Verwendung einer Führung 13 wie im Experiment (C) nach oben oder nach unten gelenkt. Wenn die Führung 13 den Transportwinkel des thermochromischen Aufzeichnungsmediums 1 lenkte, nachdem die Oberflächentemperatur des thermochromischen Aufzeichnungsmediums 1 auf einen Wert unter 60°C verringert wurde, traten in dem thermochromischen Aufzeichnungsmedium 1 Wellen auf, vorausgesetzt die Basis (Papier oder PET) besitzt eine Dicke von 0,05 mm bis 0,22 mm. Wenn dagegen der Transportwinkel geändert wurde, bevor die Oberflächentemperatur des thermochromischen Aufzeichnungsmediums 1 insgesamt auf einen Wert unter 60°C verringert wurde, traten keine Wellen auf.
• (G) Ein thermochromisches Aufzeichnungsmedium mit Kartengröße, das eine Basis 1 aus PET und eine Dicke von 0,25 mm aufweist, wurde hergestellt. Bei diesem thermochromischen Aufzeichnungsmedium traten bei den oben genannten Bedingungen (A) bis (F) keine Wellen auf.

Experiments to eliminate unwanted waves 15 were carried out by the inventors using a thermochromic recording medium whose thickness is similar to the thickness of plain paper. The quenching temperature for the thermochromic medium 1 with a thickness of plain paper is about 100 ° C to 160 ° C.

• (A) A thermochromic recording medium 101 became the extinguishing thermal head 121 fed horizontally and using the conventional extinguishing device, which in 1A is heated to 100-160 ° C. The heated thermochromic recording medium 101 was from the erase thermal head 121 guided in a straight line in a horizontal direction.
• (B) A thermochromic recording medium 1 became the extinguishing thermal head 21 fed horizontally and using a deletion device 10 , in the 3A is heated to 100-160 ° C. The heated thermochromic recording medium 1 was then led obliquely upward at a certain angle to the horizontal along the transport path indicated by the arrows. In this case, the waves were 115 considerably reduced and depending on the thickness of the medium no waves occurred. If the angle of the transport path to the horizontal was set at 30 ° or larger, no waves occurred, assuming the thickness of the base 2 (made of paper or PET) of the thermochromic recording medium 1 was 0.05 mm to 0.22 mm.
• (C) A thermochromic recording medium 1 gets the erase thermal head 21 fed horizontally and heated to 100-160 ° C. The heated thermochromic recording medium 1 is then at a certain angle to the horizontal along the transport path, which is indicated by the arrows, naturally guided downwards by gravity, as in 3B is illustrated. In this case, the waves were 115 considerably reduced and no waves occurred depending on the type of medium. When the angle of the downward transporting path to the horizontal was 30 ° or larger, no waves occurred.
• (D) A thermochromic recording medium 1 became the extinguishing thermal head 21 fed horizontally and heated to 100-160 ° C. The heated thermochromic recording medium 1 was along the transport route under the control of a guide 13 either obliquely upwards or obliquely downwards, as in the 3A or 3B is illustrated. In this case, the angle of the transport path through the guide 13 controlled and there were no waves when the angle was controlled to 30 ° or more.
• (E) A thermochromic recording medium 1 was the extinguishing thermal head 21 fed horizontally and heated to 100-160 ° C. The heated thermochromic recording medium 1 was from the erase thermal head 21 passed through a guide with a curved surface. This experiment was performed by specifying the radius of curvature of the curved Surface was changed. The undulations on the erased thermochromic recording medium 1 were greatly reduced, and especially when the radius of curvature was set to 40 mm or less, no waves occurred.
• (F) A thermochromic recording medium 1 became the extinguishing thermal head 21 fed horizontally and heated to 100-160 ° C. The heated thermochromic recording medium became after the erasing thermal head 21 straightforward for a certain distance, as in 4 is illustrated. Then, the transporting direction of the thermochromic recording medium became 1 using a guide 13 as directed in experiment (C) upwards or downwards. If the leadership 13 the transport angle of the thermochromic recording medium 1 After the surface temperature of the thermochromic recording medium 1 was lowered to a value lower than 60 ° C occurred in the thermochromic recording medium 1 Waves, provided the base (paper or PET) has a thickness of 0.05 mm to 0.22 mm. In contrast, if the transport angle has been changed before the surface temperature of the thermochromic recording medium 1 was reduced to a value below 60 ° C, no waves occurred.
• (G) A card-sized thermochromic recording medium having a base 1 made of PET and has a thickness of 0.25 mm was prepared. In this thermochromic recording medium, no waves occurred in the above-mentioned conditions (A) to (F).

Out The experimental conclusions will be the following conclusions drawn.

First, it is apparent from experiments (A) to (E) that in the thermochromic recording medium 1 Form waves unless there is some form of physical action on the heated thermochromic recording medium 1 during the process in which the thermochromic recording medium becomes rigid after heating. Since the thermochromic recording medium 1 contains several layers (the base 2 , the thermochromic layer 3 , the translucent protective layers 4 and 5 and the recoating layer 6 ) made of different materials with different rates of heat contraction, these layers have different thermal deformations in the cycle of heating under pressure and sudden release for cooling. To prevent the thermochromic recording medium 1 Waves forming, must be a rapid cooling of the thermochromic recording medium 1 be avoided or the thermochromic recording medium must be kept in the cooling process during its consolidation under tensile stress. The former method (ie, slow cooling) is impractical since it is known from another experiment that cooling of the thermochromic recording medium 1 Without forming waves, takes a relatively long time. This results in a strong reduction of the deletion speed and the transport speed. The latter method is much better because the mutual reaction of the overlying layers caused by thermal contraction can be prevented by solidifying the thermochromic recording medium 1 is used, wherein during the cooling process on the thermochromic recording medium 1 a tensile stress is applied. This method does not adversely affect the erasing speed or the size of the device.

Second, it is concluded from experiment (F) that on the thermochromic recording medium 1 a tensile stress should be exerted when the surface temperature of the thermochromic recording medium 1 at 60 ° C or above. 5 illustrates the temperature profiles of the thermochromic recording media 1 that in the 4 correspond to the structure shown. These profiles were based on measurements of temperature sensors 16 and 17 receive. The thermochromic recording medium 1 is through a belt-shaped heater 24 of the extinguishing thermal head 21 constantly heated to a quenching temperature T0 (120 ° C) and cooled along the transport path. The sensors 16 and 17 are movable along the transport path at a speed which corresponds to the straight-line speed of the transport path. The sensors 16 and 17 used in the experiment were infrared emission thermometers (IT2-50 manufactured and sold by Keyence Inc.).

In the thermochromic recording media A and B whose surface temperatures were between 60 ° C and 100 ° C, no waves occurred when they reached the point B where tensile stress was applied to the recording media A and B by inclining the transport path. At temperatures of 60 ° C to 100 ° C, the thermochromic recording medium began 1 to solidify. On the other hand, waves occurred in the thermochromic recording medium C whose surface temperature at point B was lower than 60 ° C. Waves also occurred in the thermochromic recording medium D even when its surface temperature at point B exceeded 60 ° C. This was the case because the surface temperature of the recording medium D was over 100 ° C, and even at the end point Q, hardening still occurred had not started. The recording medium D, while starting to harden, is further cooled along a horizontal path (not shown) without further application of a tensile stress.

In a conventional rewritable printing apparatus, thermochromic recording media 1 To erase and reprint the A4 size at a high rate, such as tens of pages per minute (PPM), a long transport path is required to thermochromic the recording media 1 to cool sufficiently. On the other hand, the erasing apparatus of the present invention is adapted to the thermochromic recording medium 1 effectively cools by providing a heat exchanger or a heat sink with a good thermal conductivity along the inclined or curved path which extends between the points P and Q. This arrangement allows for fast transport. When the transport speed is slower (for example, some PPM), the thermochromic recording medium becomes 1 cooled sufficiently along the inclined or curved path without the use of a heat exchanger. Another feature is that the erasing device of the present invention, the hardening of the thermochromic recording medium 1 used during the cooling process under tensile stress. This arrangement effectively prevents the thermochromic recording medium 1 Waves forming.

With respect to the surface temperature, it is necessary that the thermochromic recording medium 1 at point B has a surface temperature of 60 ° C or more and at point P has a temperature below 60 ° C, wherein the recording medium 1 Waves, even if it is transported along the slope, since it is almost impossible to control the surface temperature when it falls below the point P to a value below 60 ° C. The importance of the temperature profile along the rectilinear path is emphasized since the formation of waves by the thermochromic recording medium 1 In particular, in a device is a phenomenon that has a linear heat distribution through the use of a heating roller or a ceramic heater. In a device that can perform temperature control throughout the device (eg, heating and cooling in an isothermal chamber), no ripples occur 15 on. As a result, it is effective that the heat roller type eraser or the ceramic heater type eraser thermochromic recording medium 1 from the heater 24 while pulling is applied before the surface temperature is reduced below 60 ° C.

Third, it follows from the experiment (G) that the thermochromic recording medium 1 Waves when it has a thickness of plain paper (ie 0.05 mm to 0.22 mm). A thermochromic recording medium of card size in which the base 2 a thickness of 0.25 mm, does not form waves because the rigidity and the mechanical strength are sufficient to prevent thermal deformation.

An additional experiment was performed to look for the possibility of reducing the device size. In the experiment, the temperature of the erase thermal head became 21 set to 140 ° C. Ten consecutive recording media were added to the erase thermal head 21 fed horizontally and were subjected to the erasing operation continuously. When the entire rewritable printing apparatus has been manufactured vertically, the erasing unit 20 at a higher point than the recording unit 30 The erasing quality was even in the last pages of the thermochromic recording media 1 satisfactorily maintained. This is a result of the better effect over the conventional horizontal transport path, which differs from the quenching unit 120 extends. By the deletion entity 20 is placed above and the recording unit 30 At the bottom of the device, the heat influence from the erasing unit can be avoided when the thermochromic recording medium 1 is subjected to the re-printing process. By reducing the heat influence of the quenching unit 20 can the thermochromic recording medium 1 clearly assume a color at the reprinting temperature.

Based on the experiments and observations described above, the inventors developed various types of erasers and rewritable printing devices that can prevent the thermochromic recording medium 1 in the cooling process forms ripples, and in the re-printing process enable clear coloring while keeping the device in a compact form.

First embodiment

The 6A to 6D illustrate examples of the extinguishing device 40 according to the first embodiment of the invention. The extinguishing device 40 has a deletion thermal head 21 for heating a thermochromic recording medium (not shown) 1 and a stress applying device 41 located after the thermal head and on the thermochromic recording medium 1 that by the Erasing thermal head 21 and the pressure roller 22 was heated, exerts a tensile stress. The extinguishing device 40 also has a pressure roller 22 as a printing medium containing the thermochromic recording medium 1 against the thermal head 21 suppressed. The pressure roller 22 transports the thermochromic recording medium 1 during heating to the stress applying device 41 ,

The stress applying device 41 is z. B. a guide 411 with a curved surface 411a on the upper surface, as in the 6A to 6C is illustrated, or alternatively is a guide 412 with a downwardly facing curved surface 412a , as in 6D is illustrated. The guides 411 and 412 are z. B. made of aluminum, which has a good thermal conductivity. The curved surfaces 411a and 412a define a transport route 42 , The leadership 411 (or 412 ) exercises during transport with its curved surface 411a (or 412a ) a tensile stress on the heated thermochromic recording medium (not shown) 1 and simultaneously conducts heat from the thermochromic recording medium 1 from.

The radius of curvature of the curved surfaces 411a and 412a is 40 mm or less and the curvature position from which the feed angle of the transport path changes with respect to the horizontal is set so that the surface temperature of the thermochromic recording medium 1 is still at 60 ° C or above when the thermochromic recording medium 1 reaches the curvature position. In the in 6C As shown, the curvature position starts at a distance L from the erasing thermal head 21 and a temperature sensor 16 (For example, a thermistor or a contact-type or non-contact type thermocouple) is disposed at the beginning of the curving position to the surface temperature of the thermochromic recording medium (not shown) 1 capture. A straight-line transport path extends from the erase thermal head 21 over the distance L and the curved transport path 42 starts at the curvature position where the sensor is 16 is provided. The distance L may vary depending on the transport speed of the thermochromic recording medium 1 to change.

The extinguishing device may further comprise an auxiliary guide 413 having the same radius of curvature as the curved surface 411a (or 412a ), as in the 6B and 6D is illustrated. The auxiliary guide 413 is also made of a material having a heat-radiating ability. In this case, the thermochromic recording medium (not shown) becomes 1 between the leadership 411 (or 412 ) and the auxiliary guide 413 guided and the cooling effect of the transport route 42 is further improved. If this structure at the in 6C As shown in the example shown, the distance L can be reduced due to the improved heat radiating function. In this way, the thermochromic recording medium becomes 1 at the surface temperature of 60 ° C or above along the curved surface 411a (or 412a ) the leadership 411 (or 412 ) and during transport becomes to the thermochromic recording medium 1 exercised a tensile stress. The thermochromic recording medium 1 becomes rigid during the cooling process under tensile stress without any ripples.

Second embodiment

The 7A and 7B illustrate examples of the extinguishing device 40 according to the second embodiment of the invention. In the second embodiment, instead of the curved surface, the guide has an inclined surface or inclination to change the transport angle.

In 7A owns the extinguishing device 40 a guide 414 with a sloped surface 414a that a transport route 43 Are defined. In 7B owns the extinguishing device 40 a guide 414 with a downwardly inclined surface 414a and an auxiliary guide 415 that is shaped to guide you 414 equivalent. The leadership 414 and the auxiliary guide 415 are made of a thermally conductive material, such as aluminum. The thermochromic recording medium 1 hits after it clears the thermal head 20 happened on the inclined surface 414a What the heated thermochromic recording medium 1 gives a rigidity. Then, the thermochromic recording medium becomes 1 along the inclined surface 414a and is cooled and hardened under the tensile stress due to gravity. When the angle of inclination of the surface 414a is set to a value of 30 ° or more, the stretching effect becomes larger and larger in the thermochromic recording medium 1 with a thickness of plain paper (the base 2 has a thickness of 0.05 mm to 0.22 mm), wave formation is effectively prevented.

Third embodiment

The 8A to 8D illustrate examples of the extinguishing device 40 according to the third embodiment of the invention. In the examples given in the 8A and 8B shown has the extinguishing device 40 a group of roles 416 which contain several auxiliary rollers. These roles 416 function as a stress exerciser. The group of roles 416 is so confused gurgled that they have a curved transport path 42 define how in 8A or is configured to alternatively take a tilted path 43 define how in 8B is shown.

In 8C becomes a fan 417 used as a stress applying device. The fan 417 applies the wind force obliquely from below to the extinguishing thermal head 20 an upward transport route 42 to build. In this structure, the thermochromic recording paper becomes 1 is transported under tensile stress along a slight curve while it is effectively cooled. The power of the blower 417 is dependent on the thickness of the thermochromic recording medium (not shown) 1 and the transport speed set.

In 8D Become a belt and a group of rollers 416 used as the stress applying device. The roles 416 are arranged so that they have a curved transport path 42 define, and the belt 418 runs around the rollers 416 , This arrangement achieves stable transport of the thermochromic recording medium 1 , By adjusting the arrangement of the rollers 416 becomes the radius of curvature of the transport path 42 set as desired.

Fourth embodiment

The 9A to 9G illustrate examples of a rewritable printing device 10 in which an erasing device described in the first to third embodiments is mounted. The rewritable printing device 10 contains a deletion unit 20 comprising a thermochromic recording medium (not shown) 1 to a first temperature T1 heats to the thermochromic recording medium 1 delete printed images; a stress applying device 41 after the erase thermal head 21 is arranged to a tensile stress on the heated thermochromic recording medium 1 exercise; and a recording unit 30 after the exercise device 41 is arranged and the thermochromic recording medium 1 heated to a second temperature T2 to again images on the erased thermochromic recording medium 1 to print.

The stress applying device 41 defines a curved transport path 42 (the 9A - 9D and 9G ) or a sloped transport route 43 (the 9E and 9F ) between the deleting unit 20 and the recording unit 30 , The thermochromic recording medium 1 is transported along this transport path while being subjected to tensile stress exerted by the stress applying means 41 is exercised. The stress applying device 41 carries the erased thermochromic recording medium 1 the recording unit 30 too, without causing waves. The recording unit 30 has a recording thermal head 31 and the pressure roller 32 against which the recording thermal head 31 over the thermochromic recording medium 1 is pressed. Because in the thermochromic recording medium, which belongs to the recording unit 30 is transported, no waves occur during the re-printing operation in the recording unit 30 good contact between the recording thermal head 31 and the thermochromic recording medium 1 maintained. As a result, clear images can be formed stably.

Fifth embodiment

The 10A and 10B illustrate examples of the rewritable printing apparatus 10 according to the fifth embodiment of the invention. In the fifth embodiment, the rewritable printing apparatus has 10 a temperature sensor 16 on the transport route 43 who is from the extinguishing unit 20 extends.

In the in 10A The example shown comprises the stress applying device 41 a couple of guides 414 , the inclined surfaces 414a exhibit a curved transport path 43 define. One of the guides 414 owns a window 419 at the bending position. The temperature sensor 16 measures the surface temperature of the thermochromic recording medium 1 along the curved transport path 43 is transported through the window 419 , The measured value of the temperature sensor 16 becomes the erase thermal head 21 the extinguishing unit 20 returns and controls the erasing temperature of the erasing thermal head 21 , so that the surface temperature of the thermochromic recording medium 1 at the bending position is 60 ° C or above. The thermochromic recording medium 1 that by the erase thermal head 21 was heated, hits the inclined surface 414a the leadership 414 and changes its way along the inclined surface 414a , Consequently, the thermochromic recording medium 1 a tensile stress while the thermochromic recording medium 1 along the transport route 43 is cooled.

In 10B is between the recording unit 30 and the paper ejection rollers 18 a way switch 19 arranged. The way switch 19 is with the temperature sensor 16 connected. When the detected surface temperature of ther mochrome recording medium 1 is below 60 ° C, the way switch switches 19 the transport route to the way back 45 to the newly printed thermochromic recording medium 1 to the input tray 11 recirculate. At the same time, the detection result of the temperature sensor becomes 16 to the erase thermal head 21 delivered to increase the extinguishing temperature. The returned thermochromic recording medium 1 is again subjected to the deletion and re-printing processes. In this way, recording errors are effectively prevented in advance.

Sixth embodiment

The 11A and 11B illustrate examples of the extinguishing device 40 according to the sixth embodiment of the invention. In the sixth embodiment, the erasing device is 40 of the vertical type. The extinguishing device 20 is under the feed rollers 50 positioned and a transport route 44 acting as a stress exerciser 41 acts, extends from the deletion unit 20 downwards in the direction of gravity. In this example, the tensile stress becomes more effective on the heated thermochromic recording medium 1 exercised. Instead of the thermal head 21 become heating rollers 23 used to thermochromic recording medium 1 to heat.

In 11B Contains the exercise device 41 a vertical path 44 and a curved path 42 that is different from the vertical way 44 extends uninterruptedly. As a result, a tensile load due to gravity and the tensile stress caused by the curved path 42 gives, on the thermochromic recording medium 1 twice exercised. This arrangement allows the extinguishing device 44 is compact and can easily be placed on a table.

In all the examples in the 11A or 11B are shown is the deleting unit 20 in the upper part of the device 40 positioned so that heat is easily removed from the transport path 44 or 42 can be dissipated. This arrangement prevents accumulation of heat at the bottom of the device 40 , The heated thermochromic recording medium 1 can be effectively cooled under a tensile load due to gravity.

The heat released to the top of the device can be reused to the thermochromic recording medium 1 that the feed rollers 50 is fed, preheat. This preheating may change the temperature on the way from the feed roller 50 to the extinguishing unit 20 make it less, causing wrinkling of the thermochromic recording medium 1 is prevented.

12 illustrates an example of the rewritable printing apparatus 10 in which a vertical type extinguisher is mounted. A recording unit 30 is on the outlet side of the transport route 42 positioned. The thermochromic recording medium 1 becomes the recording unit 30 without the formation of waves after it has been sufficiently cooled. As a result, the newly printed image has good color characteristics. The newly printed thermochromic recording medium 1 will be in the tray 14 pushed out. This rewritable printing device 10 Can stably repeat the erasing and printing without degrading the picture quality.

Seventh embodiment

13 illustrates an example of the rewritable printing apparatus 10 according to the seventh embodiment of the invention. The rewritable printing device 10 has a U-shaped transport route 42 who is from the extinguishing unit 20 extends. A recording unit 30 is at the opposite end of the U-shaped path 42 and the re-printed thermochromic recording medium becomes the feed tray again 11 ejected, as indicated by the dashed arrow. The U-shaped path 42 may be the heated thermochromic recording medium 1 give a rigidity, if a sufficiently long cooling area is ensured. As a result, the appearance of waves can be prevented and clear images can be reproduced on the heated thermochromic recording medium 1 to be printed.

The U-shaped transport route 42 is z. B. by a guide 45 , which is made of aluminum and has a U-shaped surface defined. Alternatively, it may be defined by rollers, a belt, or a combination thereof. In order to reduce the device size, it is preferable to provide a curved guide for guiding the thermochromic recording medium after being subjected to erasing and re-printing to the feeding tray 11 of which the recovered thermochromic recording medium 1 to the device 10 is delivered. By adjusting the radius of curvature of the U-shaped transport path 42 to 40 mm or more, any types of the thermochromic recording media having a thickness of plain paper may be independent of the material of the base 2 (eg paper, PET, etc.).

14 illustrates a modification of rewritable printing device 10 in which the U-shaped transport route 42 through a group of roles 416 is defined, and 15 illustrates another modification of the rewritable printing apparatus 10 in which the U-shaped transport route 42 through a belt 418 and auxiliary roles is defined. In all examples is a temperature sensor 16 at the output of the erase unit 20 arranged and after the temperature sensor 16 the transport route changes 42 the orientation of the transported thermochromic recording medium 1 ,

16 (A) illustrates another modification of the rewritable printing apparatus 10 , This rewritable printing device 10 has a cooling fan 47 and a guide 45 , in the 16 (B) are shown. The leadership 45 has one or more grooves 46 extending along the longitudinal axis of the guide 45 extend to work in conjunction with the blower 47 Heat from the thermochromic recording medium 1 dissipate. This arrangement can further improve the cooling effect while a tensile stress on the thermochromic recording medium 1 is exercised without increasing the device size.

Eighth embodiment

17 illustrates an example of the rewritable printing apparatus 10 according to the eighth embodiment of the invention. The device 10 contains a first temperature sensor 16 at the beginning of the U-shaped transport route 42 is positioned, and a second temperature sensor 17 at the end of the U-shaped transport route 42 is positioned. The extinguishing temperature of the extinguishing unit 20 is based on the output of the first sensor 16 controlled so that the surface temperature of the thermochromic recording medium 1 passing through the sensor 16 is detected, is 60 ° C or greater. Further, the temperature of the U-shaped transport path 42 z. B. by adjusting the power of the fan 47 ( 16 (A) ) based on the output of the second temperature sensor 17 controlled so that the surface temperature of the thermochromic recording medium 1 100 ° C or below.

The extinguishing temperature of the extinguishing unit 40 varies by ± 10 ° C depending on the material of the thermochromic layer 3 ( 2 ). When the heat energy of the quenching unit 20 is changed so that it for the actually used thermochromic recording medium 1 is suitable, the surface temperature of the thermochromic recording medium 1 at the end of the transport route 42 still above 100 ° C. In this case, the thermochromic recording medium becomes 1 wavy and the newly printed image by the recording unit 30 is recorded deteriorates. To avoid this situation, the second temperature sensor 17 used to determine the surface temperature of the recording medium 1 at the end of the transport route 42 to monitor.

18 Fig. 12 illustrates a modification of the rewritable printing apparatus 10 this embodiment. This modification has a way switch 51 and a test sheet ejection path 52 between the recording unit 30 and the end of the transport route 42 , The way switch 51 switches the path between the normal discharge path 46 and the test sheet ejection path 52 around. In this device, the erasing temperature of the erase unit before the actual deletion and reprinting 20 and the temperature of the U-shaped transport path 42 through the first and the second sensor 16 and 17 set using a test sheet. In the test mode, the ejection path is also through the path switch 51 on the test sheet discharge path 52 set and a test sheet is taken from the input tray 11 delivered. The test sheet is subjected to the deletion and follows the transport route 42 , The way switch 51 Switches the way back to the normal way 46 if the surface temperature of the test sheet at the beginning of the transport path 42 60 ° C or above and will be at the end of the transport route 42 100 ° C is or less.

19 Fig. 10 is a flowchart showing the switching operations described above. In step S901, a test sheet of the apparatus 10 fed. In step S902, a first surface temperature T _{A is} determined by the first sensor 16 at the beginning of the transport route 42 detected. In step S903, it is determined whether or not the detected first temperature T _{A is} 60 ° C. If the detected temperature is lower than 60 ° C (No in S903), the test sheet discharge path becomes 52 through the way switch 51 is selected (S904) and the erasing temperature of the erasing unit 20 is set in step S905. Then, the process returns to step S901 and repeats steps S901 to S903. When the detected temperature is 60 ° C or above (Yes in S903), the second surface temperature T _B becomes through the second sensor 17 at the end of the transport route 42 detected. In step S907, it is determined whether the detected second temperature T _{B is} 100 ° C or less. When the detected temperature is over 100 ° C (NO in S907), the process returns to step S904 in which the check sheet discharge path 52 is selected. If the detected second temperature T _{B is} 100 ° C or below (Yes in S907), the regular feeding operation starts to actually record the thermochromic recording medium in step S908 1 supply. In this way Erasing and re-printing are performed stably and reliably in a temperature control.

20 Fig. 12 illustrates another modification of the rewritable printing apparatus of this embodiment. In this modification, the transport path extending between the deletion unit 20 and the recording unit 30 extends, a combination of a sloping path 44 and a U-shaped path 42 , The inclined path 44 extends from the deletion unit 20 at an angle equal to or greater than 30 ° (eg 35 °) to the horizontal. The combination of the guide with grooves and the cooling fan, which in 16A can be applied to this structure.

Ninth embodiment

In the fifth, seventh and eighth embodiments, the erasing temperature becomes the surface temperature of the thermochromic recording medium 1 controlled at the beginning (and at the end) of the transport path extending from the deleting unit. In the ninth embodiment, the erasing temperature of the erasing unit becomes 20 controlled by the temperature of the thermal head (or heating roller) and the pressure roller. This ensures a more direct control to keep the extinguishing temperature constant, around the entire surface of the thermochromic recording medium 1 to heat evenly with A4 size.

Prior to the description of the ninth embodiment, the erasing characteristics of the thermochromic recording medium become 1 in terms of temperature explained. The 21A and 21B Fig. 15 are diagrams showing the erasure characteristics of various types of thermochromic recording media. The 22A and 22B illustrate chemical formulas of the developer and the leuco dye used in the thermochromic recording media shown in the figures of Figs 21A and 21B are shown.

Of the Range of extinguishing temperatures changes in the different types of thermochromic recording media and some recording media have a narrow allowable range of 10 ° C Or less. When using a thermochromic recording medium for documents will have to Images are completely erased on the thermochromic recording medium, since even a small amount of the remaining image will be the image quality of the new printed recording medium adversely affected. The permissible color density of the remaining image (after erasing) on a conventional one thermochromic recording medium of the card type is practical Use about 0.02. The color density of the residual image must be against it when used for Certificates be 0.01 or less. That means a controller the extinguishing temperature for a thermochromic recording medium used as a certificate will, is much stricter.

Another experiment was conducted to determine the relation between the heating roll temperature and the color density of the residual image after erasing at various transport speeds using the test quenching apparatus 400 , in the 23B is shown to receive. The tester 400 has a deletion unit 401 that has a heating roller 402 and a pressure roller 404 contains. The heating roller 402 is a stainless steel pipe with a diameter of 40 mm and a thickness of 30 mm. A halogen lamp 403 is arranged in the stainless steel tube. The pressure roller 404 is made of silicone rubber with a hardness (Hs) of 50 (JIS-A) and a thickness of 4 mm.

The base 2 of the test sheet 410 used in the experiment was plain paper having a thickness of 110 μm. The thermochromic layer 3 of the test sheet contained developer PAU0-5-18 which was used in 22A and leuco dye L1, which is shown in FIG 22B is shown. The thickness of the thermochromic layer 3 was about 10 microns. The test sheet carried a square image (8 mm × 8 mm) with a color density of 1.00-1.05.

24 Figure 13 is a diagram showing the appropriate temperature range for erasing at each transport speed. At the transport speed of 20 mm / sec, the printed image was completely erased at an erasing temperature in the range of 120 ° C to 170 ° C. At 30 mm / s, the quenching temperature was in the range of 130 ° C to 170 ° C, and at 50 mm / s, the quenching temperature was in the range of 150 ° C to 170 ° C. When the transport speed was increased to 80 mm / sec, the quenching temperature was in the range of 160 ° C to 170 ° C. Because the gap width between the heating roller 402 and the pressure roller 404 In this experiment, about 3 mm, the heating time at the transport speed of 20 mm / s is 0.15 seconds. The heating time decreases as the transport speed increases, and is 0.10 seconds at 30 mm / s, 0.06 seconds at 50 mm / s, and 0.04 seconds at 80 mm / s. The greater the transport speed (or the shorter the heating time), the narrower the erasing temperature range of the heating roller becomes 402 ,

The surface area of the thermochromic recording medium 410 for the document use is relatively large and it is therefore important, the temperature of the heating roller 402 to keep in the range of the extinguishing temperature, the the transport speed corresponds to the trailing edge of the recording medium 1 has completely passed through the gap position. If the eraser is used in a document usage, the total elapsed time required for each sheet must be reduced. It is Z. B. required that a thermochromic recording medium 410 A4 size with a length (from the leading edge to the trailing edge) of about 300 mm in 10 seconds through the gap section runs. Further, deformation and waviness are likely to occur on the thermochromic recording medium 410 for document use because it is large and thin compared with a card-type recording medium.

When the transport speed is set to 50 mm / s, the allowable temperature range for the heat roller is 402 20 ° C. If thermal deformations are taken into consideration, the thermochromic recording medium should 410 heated to a point near the lower limit (ie, about 150 ° C) of the temperature range under accurate temperature control. From the above, it is clear that the allowable range for an erasing device or a rewritable printing device having a practical transporting speed of 30 mm / sec or more is narrower than 10 ° C, and preferably narrower than 5 ° C. For this reason, it is necessary to change the temperature of the heating roller 402 to control with high accuracy.

To realize this, the pressure roller becomes 404 rotated and preheated before the actual extinguishing operation, so that both the heating roller 402 as well as the pressure roller 404 reach a thermal equilibrium before the thermochromic recording medium 410 enters the gap section. In thermal equilibrium is the temperature of the pressure roller 404 about 15-30 ° C lower than that of the heating roller 402 , By using a heating roller 402 with a large heat capacity and by adjusting the temperature of the pressure roller 404 to a relatively high value, the temperature drop in the gap portion during the passage of the thermochromic recording medium 410 kept small.

On the other hand, from the viewpoint of energy saving, the halogen lamp should be used 403 the heating roller 402 be turned on only during the actual operation of the device. The rise time (ie the time that the heating roller 402 and the pressure roller 404 however, to achieve thermal equilibrium) must be as short as possible when the device is actually used. To reduce the rise time, the thickness of the stainless steel tube becomes the heating roller 402 thinned to reduce the heat capacity. The smaller the heat capacity of the heating roller 402 is, the greater is the tempera ture change of the heating roller 402 due to heat conduction to the thermochromic recording medium 410 and the pressure roller 404 which results in insufficient extinguishing ability.

To confirm this, a second experiment (Experiment 2) was performed using a 500 W halogen lamp 403 and a stainless steel tube having a thickness of 0.5 mm having an outer diameter of 15 mm and having a black heat-resistant coating on the inner surface was used. The pressure roller 404 is made of silicone rubber of hardness 30 (JIS-A) made with a thickness of 3 mm.

The heating roller 402 and the pressure roller 404 were from room temperature (about 30 ° C) by switching on the halogen lamp 403 and at the same time by turning the heating roller 402 and the pressure roller 404 at a rate corresponding to the prescribed transport speed, heated. The temperatures of the heating roller 402 and the pressure roller 404 were monitored by thermocouples (manufactured and sold by Anritsu) (not shown) which were controlled in two-point operation by a controller (E5CK-QR1, manufactured and sold by Omron). After reaching the setting temperature (150-160 ° C), the temperature of the heating roller 402 controlled in the range of ± 3 ° C.

Ten seconds after the start of heating, the temperature of the heating roller was 402 140 ° C and a test sheet carrying an 8 mm x 8 mm square image were fed to the nip portion at a speed of 30 mm / sec to erase the square image. The picture was not completely deleted. The color density of the remaining image was 0.02-0.08.

In a third experiment (Experiment 3), a test sheet bearing the same image was supplied to the nip portion at a rate of 30 mm / s 22 seconds after the start of heating. The other conditions were the same as in Experiment 2. In this case, the image was satisfactorily erased and the color density of the erased surface of the test sheet (thermochromic recording medium 410 ) was 0.01 or less.

When the temperature of the heating roller 402 was set to 160 ° C, the printed image was also satisfactorily erased at a color density lower than 0.01, even if the test sheet 10 Seconds after the start of heating was fed to the nip section (Experiment 4).

In Experiments 2 and 3, the surface temperature of the pressure roller became 404 in any case measured by the thermocouple. 25 is a representation showing the temperature change of the pressure roller 404 shows when the heating roller 402 was set to 140 ° C. In Experiment 2, the surface temperature of the pressure roller changed 404 during the erase operation from 55 ° C to 48 ° C and in Experiment 3, the temperature of the pressure roller changed 404 from 65 ° C to 57 ° C. Although not shown in the diagram, the temperature drop of the pressure roller was 404 much lower in experiment 4, where the temperature of the pressure roll 404 from 56 ° C to 50 ° C with the heat roller 402 changed whose temperature was set to 160 ° C.

This means that the printed image is satisfactorily erased when the temperature of the pressure roller 404 is larger. That is the case, because then when the temperature of the pressure roller 404 is low, heat slightly from the heating roller 402 through the thermochromic recording medium 410 to the pressure roller 404 flows. In this case, the temperature reaches the thermochromic layer 3 the thermochromic recording medium 410 not the surface temperature of the heating roller 402 , which is measured by the thermocouple.

In a further experiment (experiment 5) the halogen lamp was used 403 after the test sheet was subjected to the erase operation under the conditions of Experiment 3 and the rotation of the heat roller 402 and the pressure roller 404 was stopped. The eraser was turned on again twenty (20) seconds after the power was turned off. The temperature of the heating roller 402 reached 140 ° C five seconds after restart (turn on) and a new test sheet was fed to the nip section. The temperature of the pressure roller 404 changed from 67 ° C to 59 ° C when the test sheet (thermochromic recording medium) 410 through the gap section. The image on the new test sheet was satisfactorily erased even with the rise time of just five seconds.

From the observation results of Experiments 2 to 5, it is confirmed that reliable erasing and reduced rise time are attained simultaneously by setting the erasing conditions by the temperature of the pressure roller 404 be adjusted in a suitable manner. The temperature of the heating roller 402 is z. B. set to 160 ° C when the surface temperature of the pressure roller 404 40 ° C or less. The heating roller 402 is set to 150 ° C when the surface temperature of the pressure roller 404 is above 40 ° C and 60 ° C or less, and the heating roller 402 is set to 140 ° C when the temperature of the pressure roller 404 greater than 60 ° C. The selection of the appropriate quenching conditions can prevent the thermochromic recording medium 410 Waves or deforms.

In the sixth experiment (Experiment 6 ), the temperature of the heating roller 402 set at a constant temperature (eg 150 ° C) and the transport speed is reduced to 15 mm / s. A test sheet (ie a thermochromic recording medium) 410 bearing the same image was fed to the nip section after ten seconds. The color density of the erased test sheet was less than 0.01. In this case, instead of changing the temperature of the heating roller 402 the transport speed based on the temperature of the pressure roller 404 set. By reducing the transport speed, the heating time of the thermochromic recording medium becomes 410 long. Even if the temperature of the pressure roller 404 something is low and even if the temperature drop of the heating roller 402 Accordingly, at the nip portion, the thermochromic recording medium can become 410 be heated in the correct range of the extinguishing temperature in a suitable manner. When a number of thermochromic recording media are supplied to the apparatus, the first medium may take a slightly longer time, however, the erasing operation for the second medium and the following media becomes shorter because the temperature of the pressure roller 404 increases with progressive surgery. To thermal stresses on the thermochromic recording medium 410 to avoid, which can be effected when the heating time is too long, the transport speed is chosen so that the thermal stresses are minimized while allowing the thermochromic recording medium 410 through the heating roller 402 is heated sufficiently.

In the seventh experiment (Experiment 7), the heating roller became 402 constantly set to 150 ° C and the pressure of the pressure roller 404 was doubled when the surface temperature of the pressure roller was not sufficiently high. A test sheet 410 was fed to the nip section after ten seconds at a speed of 30 mm / sec. The color density of the erased test sheet was less than 0.01. By increasing the pressure of the pressure roller 404 the area of the gap section between the heating roller increases 402 and the pressure roller 404 and the heating period for one unit area of the thermochromic recording medium 410 becomes larger. In addition, the thermochromic recording medium 410 with the heating roller 402 gets into close contact, heat goes directly to the thermochromic layer 3 of the recording medium 410 over, effectively erasing the printed image.

Adjusting the temperature of the heating roller 402 and / or the transport speed and / or the pressure of the pressure roller 404 can also at the extinguishing device 303 , in the 23A is shown to be applied. In this case, instead of the heating roller 402 with the halogen lamp 403 the heating substrate 302 with a belt-shaped heating device 303 used. This will cause the temperature of the heating substrate 303 and / or the transport speed of the thermochromic recording medium 310 and / or the pressure of the pressure roller 304 based on the temperature of the pressure roller 304 suitably selected. As a result, the images on the reused thermochromic recording medium 310 uniformly erased over the entire area without causing the thermochromic recording medium 310 Waves or deforms.

As a control operation, the temperature of the pressure roller becomes 404 controlled by the direct measurement of the surface temperature of the pressure roller itself. In the condition that the temperature of the heating roller 402 is set to 140 ° C, z. B. the thermochromic recording medium 410 supplied to the nip portion when the surface temperature of the pressure roller 404 Reached 65 ° C. In this case, the timing of the transport is also controlled. By a suitable selection of the material and the thickness of the heating roller 402 can the temperature of the pressure roller 404 be raised from room temperature rapidly to 65 ° C (eg in this experiment in 17 seconds).

As a second example of the control operation, the transport of the thermochromic recording medium starts when the temperature of the pressure roller 404 has reached the prescribed temperature and also if the temperature of the heating roller 402 has reached the preset extinguishing temperature. This arrangement ensures reliable erasing. In Experiments 2 to 7 described above, z. B. the transport of the thermochromic recording medium started when the heating roller 402 Reached 140 ° C and the pressure roller 404 Reached 65 ° C. In this case, the image printed on the thermochromic recording medium was completely erased.

In a third example of the control operation, in which the extinguishing device 400 has fixed conditions, the time period for reaching a predetermined temperature is experimentally known in advance. Consequently, the preheating time for the pressure roller 404 based on the initial temperature of the pressure roller 404 be selected at the beginning of the erase operation. In this context, the preheat time is a period of time from the turn on of the halogen lamp 403 (and the simultaneous start of the rotation of the heating roller 402 and the pressure roller 404 ) to start the transport of the thermochromic recording medium 410 , This process is simpler than changing the timing of transportation while the surface temperature of the pressure roller 404 is constantly monitored. The heating roller 402 must of course have reached the extinguishing temperature as a prerequisite. For this purpose, it is preferable to transport the thermochromic recording medium 1 to start when the preheat time has expired and when the heat roller 402 reaches the specified temperature.

In a fourth example of the control operation, the rise time from room temperature to the quenching temperature is reduced. In order to reduce the rise time, the first and the second setpoint temperature in the heating roller can 402 be set. Immediately after the start of heating, the target temperature is set higher than the actual extinguishing temperature, since the heat conduction to the pressure roller 404 is great. This temperature is the first set temperature. When a predetermined time has elapsed or when the measured temperature exceeds a predetermined value, the set temperature is set to the actual extinguishing temperature (ie the second set temperature). In the experiments described above, z. B. the temperature of the heating roller 402 was set to 170 ° C (the first temperature) immediately after the start of the erasing operation, and the target temperature was changed to 150 ° C (the second target temperature) when the measured temperature of the heat roller 402 130 ° C exceeded. This arrangement allows the temperature of the heating roller 402 increases rapidly, whereby the rise time can be shortened. Three or more set temperatures can be set to more accurately control the temperature.

The 26A and 26B illustrate the extinguishing device 60 according to a first proposal which does not correspond to the claimed invention. The extinguishing device in 26A is shown uses a heat roller 65 with a halogen lamp 66 as a heating medium while the extinguishing device 60 , in the 26B is shown, a heating substrate 65a with a heater 66a (For example, a belt-shaped heater having a width of 3 mm) is used as the heating means.

The extinguishing device 60 in both 26A and 26B contains heating medium 65 for heating a thermochromic recording medium 1 to erase an image in the thermochromic recording medium, and a pressure roller 67 for pressing the thermochromic recording medium 1 against the heating means 65 , The extinguishing device 60 also includes a first sensor 68 for detecting the temperature of the pressure roller 67 , a second sensor 69 to capture the Temperature of the heating roller 65 and a temperature control unit 63 for setting a target temperature and for controlling the temperature of the heating roller 65 to the setpoint temperature based on the measurement of the first sensor 68 (ie the temperature of the pressure roller 67 ) to reach.

The extinguishing device 60 also includes a transport control unit 64 for determining the timing of the transport and the transport speed based on the measurement of the first sensor 68 , a source of power 61 , a drive unit 62 and, if necessary, feed rollers 71 , The pressure roller 67 can instead of the feed rollers 67 act as a feed roller.

The temperature control unit 63 and / or the transport control unit 64 act as deletion condition control means, the erasing conditions, the temperature of the heating roller 65 , the transport speed and the timing of the transport of the thermochromic recording medium 1 contain, taxes.

The erase operation starts upon operation of a start button (not shown) by a user or upon detection of the insertion of the thermochromic recording medium 1 , The pressure roller 67 starts to turn and the first sensor 68 monitors the temperature Tr of the pressure roller 67 , The temperature control unit 63 selects a suitable set temperature, which is set in advance according to the value of Tr. The temperature control unit 63 controls the two-point operation of the halogen lamp 66 the heating roller 65 to the temperature of the heating roller 65 to raise to the selected set temperature and the heating roller 65 to keep at the target temperature.

If the second sensor 69 detects that the temperature of the heating roller 65 has reached the set temperature, a signal from the temperature control unit 63 to the transport control unit 64 delivered. The transport control unit 64 drives the feed rollers 71 to supply the thermochromic recording medium 1 to the gap portion between the heating roller 65 and the pressure roller 67 to start. While the thermochromic recording medium 1 between the heating roller 65 and the pressure roller 67 passes through, the thermochromic recording medium 1 is heated to a predetermined extinguishing temperature (ie the selected set temperature) and the image contained therein is deleted. During the run, the temperature of the heating roller 65 controlled so that it is essentially constant.

In this way, the optimum temperature of the heating roller 65 selected based on the temperature of the pressure roller and when the heating roller 65 has reached the selected temperature, this temperature is kept constant during the deletion. With this arrangement, the images can be reliably erased, and also the formation of undulations or curls of the heated thermochromic recording medium 1 greatly reduced. Even after the thermochromic recording medium 1 is repeatedly subjected to erasing and re-printing, the state of the thermochromic recording medium 1 is well maintained at a low undulation and the reliability of the erase operation is kept high.

The 26C and 26D illustrate examples of the rewritable printing apparatus 70 in which the extinguishing devices operating in the 26A respectively. 26B are shown mounted. In both examples, the rewritable printing device has 70 a recording unit comprising a recording thermal head 73 and a platen 74 on the outlet side of the extinguishing section. However, the recording unit is not limited to this example, and any type of the recording unit may be used in combination with the erasing device. The rewritable printing device 70 also has an image control circuit 75 that causes the recording thermal head 73 based on image signals supplied by a computer or other device, images on the erased thermochromic recording medium 1 generated. In this example, set heating elements of the thermal head 73 , which correspond to the picture elements of the image to be printed, electrical energy into heat and heat the thermochromic layer 3 of the recording medium 1 to a coloring temperature.

In this rewritable printing device 70 a new image becomes clear on the thermochromic recording medium 1 printed because the previously formed image is satisfactorily erased leaving a small amount of ink on it, and since the thermochromic recording medium 1 is supplied without waves or bulges of the recording unit. Even after the reprint operation is repeated a hundred (100) times, the state of the thermochromic recording medium is 1 still good.

As a modification of the extinguishing device 60 that in the 26A and 26B is shown, the transport control unit 64 based on the temperature of the pressure roller 67 passing through the first sensor 68 is detected, set a transport speed. In operation, the halogen lamp 66 (or the belt-shaped heater 66a ) and by the temperature control unit 63 maintained at a predetermined temperature (eg 150 ° C). The pressure roller 67 is rotated and the surface temperature Tr of the pressure roller 67 is through the first sensor 68 detected. The transport control unit 64 receives the monitoring result of the first sensor 68 and selects an appropriate feeding speed set in advance in accordance with the value of Tr. If the second sensor 69 detects that the temperature of the heating roller 65 (or the thermal head 65a ) has reached the predetermined temperature, activates the transport control unit 64 the drive motor (not shown) for transporting the thermochromic recording medium 1 to start at the selected speed.

In this modification, the optimum transport speed based on the temperature of the pressure roller 67 and the thermochromic recording medium 1 can be heated evenly over the entire surface. Consequently, in the thermochromic recording medium 1 deleted image, leaving a small portion of the image. In addition, the good state of the thermochromic recording medium 1 with no ripples or bulges even after the erasing and re-printing are repeated one hundred (100) times.

In a further modification of the extinguishing device 60 drives the transport control unit 64 the feed rollers 71 to transport the thermochromic recording medium 1 to begin when the temperature Tr of the pressure roller 67 reaches a predetermined temperature set as a deletion condition in advance. The thermochromic recording medium 1 is through the pressure roller 67 , which has reached the optimum temperature, against the heating roller 65 pressed. Consequently, the erasability of the erasing device 60 improved.

Tenth embodiment

The 27A and 27B illustrate examples of the extinguishing device 60 according to a second proposal, which does not correspond to the claimed invention. In this proposal, the temperature control unit 63 directly with the transport control unit 64 connected so that signals are transmitted between them. Because the difference between the structures in 27A and 27B only is that the heating means a heating roller 65 or a thermal head 65A use, an explanation is given by 27A ,

In operation, the temperature control unit receives 63 the monitoring result of the second temperature sensor 69 and provides a drive signal to the transport control unit 64 when the temperature of the heating roller 65 reaches a predetermined extinguishing temperature. The transport control unit 64 however, constantly receives the monitoring result of the first sensor 68 that is the temperature Tr of the pressure roller 67 represents. The transport control unit 64 activates the feed roller 71 to transport the thermochromic recording medium 1 to begin when the temperature Tr of the pressure roller 67 reaches a prescribed temperature and when it receives the drive signal from the temperature control unit 63 receives, indicating that the heating roller 65 has reached the extinguishing temperature.

The thermochromic recording medium 1 becomes the gap portion between the heating roller 65 and the pressure roller 67 fed, both of which are sufficiently heated to the optimum temperature. Accordingly, the entire surface of the thermochromic recording medium becomes 1 uniformly heated and those in the recording medium 1 contained images can be satisfactorily deleted without the recording medium 1 to damage. In addition, undesirable curling or curling in the erased thermochromic recording medium 1 be effectively prevented. This effect can also be achieved by the device used in the two 27A and 27B shown to be achieved.

The 27C and 27D illustrate the rewritable printing device 70 that the extinguisher used in the 27A respectively. 27B is shown contains. The rewritable printing device 70 has a recording unit as in the previous proposal. The erasing and reprinting is done using the rewritable printing device 70 that in the 27C respectively. 27D shown is repeated a hundred times. The extinguishing effect and the wave prevention effect are maintained even after the repetitions.

In a modification, the transport control unit checks 64 the temperature Tr of the pressure roller 67 that from the first sensor 68 is delivered when it receives a command to start deleting. The transport control unit 64 selects an appropriate preheat time set in advance in accordance with the value Tr. After the selected preheat time has expired, the transport control unit activates 64 the drive motor (not shown) for transporting the thermochromic recording medium 1 to start at a given feed rate. This modification also allows the pressure roller 67 is sufficiently preheated.

The control operation of the second proposal is simpler compared to that of the first one Proposal, since the transport control unit 64 the temperature Tr of the pressure roller 67 only when it receives a command to start clearing and waits for a predetermined period of time before checking the feed rollers 71 activated. This modification can achieve the same effect and can be used in the rewritable printing devices incorporated in the 27C and 27C shown are applied.

In another modification, the transportation control unit selects a preheat time as a deletion condition based on the temperature Tr of the pressure roller 67 , After the selected preheat time has expired, the transport control unit receives 64 the temperature of the heating roller 65 from the second sensor 69 via the temperature control unit 63 , The transport control unit 64 activates the drive motor (not shown) to transport the thermochromic recording medium 1 to start when the temperature of the heating roller 65 has reached a predetermined level. This arrangement ensures that both the pressure roller 67 as well as the heating roller 65 be sufficiently heated to the optimum temperatures and the same effect can be achieved.

In another modification, the temperature control unit uses 63 two different setpoint temperatures. When the temperature control unit 63 receives an erase start command, it selects a first target temperature greater than the final target temperature (or second target temperature) of the heat roller 65 is. If z. Assuming, for example, that the final (or second) set temperature is 150 ° C, the temperature control unit provides 63 the first set temperature to 170 ° C and starts heating. When the temperature of the heating roller 65 Reaches 130 ° C, changes the temperature control unit 63 the set temperature to 150 ° C, which is the final (or second) set point temperature.

This arrangement can increase the rise time for the heating roller 65 to reach the final setpoint temperature. In the example described above, the heating roller needs 65 twelve seconds to reach 150 ° C. This is three seconds faster than conventional temperature control.

The Modifications described above can be arbitrarily combined, thereby the efficiency and quality of the extinguishing can be further improved.

The 28A illustrates an example of the erasing device 60 according to a third proposal, which does not correspond to the claimed invention, and the 28B FIG. 14 illustrates an example of the rewritable printing apparatus in which the erasing apparatus of FIG 28A is included.

The third proposal is a third temperature sensor 81 disposed at the feed opening from which the thermochromic recording medium 1 in the extinguishing device 60 is introduced. The third temperature sensor 81 measures the ambient temperature near the feed opening, which is believed to be close to the surface temperature of the thermochromic recording medium 1 lies.

In operation, the heating roller begin 65 and the pressure roller 67 to turn on a command to start deleting. The first temperature sensor 68 detects the temperature Tr of the pressure roller and at the same time detects the third temperature sensor 81 the temperature To outside the extinguishing device 60 , The temperature control unit 63 selects a quenching temperature for the heating roller 65 based on the recorded temperatures Tr and To. The value of the extinguishing temperature is set in advance in accordance with the values of Tr and To. The temperature control unit 63 controls the heating roller 65 so that it is at the selected temperature via a two-point control of the halogen lamp 66 while the thermochromic recording medium 1 through the gap section.

In this proposal, the extinguishing temperature of the heating roller 65 not only the temperature of the pressure roller 67 but also the ambient temperature outside the device 60 , which approximate the temperature of the thermochromic recording medium 1 is to be considered. The optimum temperature is maintained during the erase operation. Accordingly, the entire surface area of the thermochromic recording medium becomes 1 heated uniformly without damaging it, and consequently, the reliability of erasing is improved.

Erasing and reprinting are done using the rewritable printing device 70 , in the 28B shown is repeated a hundred times. The in the reused thermochromic recording medium 1 The image contained is almost completely erased without causing curling or warping, and a new image can be applied to the erased thermochromic recording medium 1 clearly printed.

In a modification, a target temperature of the pressure roller 67 based on the outside temperature To, by the third temperature sensor 81 be determined. The transport control unit 64 activates the feed rollers 71 to transport the thermochromic Aufzeich voltage medium 1 to begin when the temperature of the pressure roller 67 passing through the first sensor 68 is detected, the selected set temperature has reached, and when the temperature of the heating roller 65 passing through the second sensor 69 is detected, has reached the set temperature. This arrangement may also have the same effect, that is, the uniform heating of the thermochromic recording medium 1 , without causing waves or bulges, reach. These effects can be maintained even after erasing and recording by the rewritable printing apparatus 70 to be repeated one hundred times.

29A illustrates an example of the erasing device 60 according to a fourth proposal which does not correspond to the claimed invention, and 29 illustrates an example of the rewritable printing apparatus 70 in which the extinguishing device, the in 29A is similar to the shown erasing device is included. The only difference from in 29A The erasing device shown is that the erasing portion of the rewritable printing apparatus 70 in 29B instead of the heating roller 65 and the halogen lamp 66 as heating medium, a heating substrate 65a and a belt-shaped heater 66a used as heating medium. The functions and effects of the heating means of both structures are the same.

In the fourth proposal, instead of the arrangement of the third sensor 81 outside the devices in the previous embodiment, a fourth sensor 82 arranged near the feed opening within the device. The fourth sensor 82 detects the surface temperature Tn of the thermochromic recording medium 1 ,

In operation, upon receiving a command to start extinguishing, the heating roller becomes 65 and the pressure roller 67 turned. The first sensor 68 detects the temperature Tr of the pressure roller 67 and the fourth sensor 82 detects the surface temperature Tm of the thermochromic recording medium 1 , which is immediately available at the feed opening. The temperature control unit 63 selects a suitable extinguishing temperature for the heating roller based on Tr and Tm 65 out. The optimum extinguishing temperature corresponding to the values of Tr and Tm is set in advance and therefore the temperature of the heating roller becomes 65 under the two-point control of the halogen lamp 66 controlled to the most suitable condition. When the temperature of the heating roller 65 passing through the second sensor 69 is detected, has reached the selected temperature, activates the transport control unit 64 the feed rollers 71 to transport the thermochromic recording medium 1 to the gap portion between the heat roller 65 and the pressure roller 67 to start. While the thermochromic recording medium 1 passes through the nip section, the temperatures of the heating roller 65 and the pressure roller 67 through the temperature control unit 63 kept at the selected temperatures.

Not only the temperature of the pressure roller 67 but also the surface temperature of the thermochromic recording medium 1 can be considered to choose the extinguishing temperature, the thermochromic layer 3 of the recording medium 1 be heated evenly over the entire surface without damage.

After the deletion operation using the in 29A In fact, the erasing device shown has actually been carried out on the thermochromic recording medium 1 printed image reliably deleted without being in the thermochromic recording medium 1 To form waves. Even after the erase operations are repeated one hundred times, the image is still reliably erased using the thermochromic recording medium 1 kept in good condition.

In addition, erasing and reprinting were performed using the rewritable printing device 70 , in the 29B is repeated a hundred times, with a recording unit disposed on the outlet side of the erasing unit. The images in the reused recording medium 1 were satisfactorily erased without residual images and without the formation of waves, and a new image becomes clear on the erased thermochromic recording medium 1 printed.

In a modification, the temperature Tr of the pressure roller 67 from the surface temperature Tm of the thermochromic recording medium 1 passing through the fourth sensor 82 is selected. The temperature control unit 63 selects a suitable setting temperature for the pressure roller 67 which is set in advance in accordance with the value of Tm. The transport control unit 64 activates the feed rollers 71 to transport the thermochromic recording medium 1 to begin when the temperature of the pressure roller 67 passing through the first sensor 69 is detected, the selected temperature has reached and when the temperature of the heating roller 65 has reached a predetermined extinguishing temperature.

In this modification, the thermochromic recording medium becomes 1 supplied to the nip portion when the temperature of the pressure roller 67 has reached the optimum temperature, which is determined by the temperature Tm of the thermochromic Aufzeich voltage medium 1 is defined, and when the temperature of the heating roller 65 has reached a predetermined temperature. Accordingly, a uniform heating over the entire surface of the thermochromic recording medium 1 realized without any unwanted damage or wave formation is effected.

The erasing operation was actually carried out using this modified erasing device and that on the thermochromic recording medium 1 Printed image was without the formation of waves in the recording medium 1 reliably deleted. Nevertheless, even after the erase operations were repeated one hundred times, the image was reliably erased while the thermochromic recording medium 1 was kept in good condition.

By using the rewritable printing apparatus incorporating the modified erasing apparatus operating in the above-described manner, the image quality of the re-printed thermochromic recording medium 1 at a high level even after the erasing and reprinting have been repeated one hundred times.

Thus, the erasing device erases the erasing device into the thermochromic recording medium 1 printed image by heating the thermochromic layer 3 to a temperature within a predetermined range. According to the ninth to twelfth embodiments, the erasing device includes a heating roller 65 or a heating substrate 65a (Which act as a heating agent), the or the thermochromic layer 3 of the recording medium 1 heated, a pressure roller 67 (which acts as a pressure medium) associated with the thermochromic recording medium 1 comes into contact to press it against the heating means, a first sensor 68 , which is the temperature of the pressure roller 67 detected, and erase state control means for controlling the erase conditions that affect the erase operation, based on the temperature Tr of the pressure roller 67 passing through the first sensor 68 is detected. The deletion condition control means includes a temperature control unit 63 and / or a transport control unit 64 , The erasing state control means controls the erasing temperature of the heating roller 65 , the transport speed and the timing of the transport of the recording medium 1 as well as other factors. In this arrangement, the temperature of the heating roller 65 set to an optimal temperature and kept on this. As a result, a uniform and reliable heating operation can be achieved within the appropriate range of the erasure temperature for the thermochromic layer 3 without excessive stress on the recording medium 1 be executed at any state.

In particular, in the first proposal, the heating control unit acts 63 as extinguishing temperature setting means and heating temperature control means. The extinguishing temperature of the heating roller 65 is through the temperature control unit 63 based on the temperature Tr of the pressure roller 67 passing through the first sensor 68 is determined. The temperature of the heating roller 65 is held at the selected temperature during the erase operation. By setting the extinguishing temperature of the heating roller 65 as one of the extinguishing conditions based on the temperature Tr of the pressure roller 67 can the reliability of the delete operation. be improved, while excessive stresses on the thermochromic recording medium 1 be reduced.

The transport control unit works in the modifications 64 as transport speed setting means and transport control means. The transport speed of the transport rollers 71 is considered one of the extinguishing conditions based on the temperature Tr of the pressure roller 67 passing through the first sensor 68 is determined. The rotation rate of the transport roller 71 is by the transport control unit 64 so regulated that the thermochromic recording medium 1 is transported at the selected speed. By a suitable control of the transport speed based on the temperature Tr of the pressure roller 67 the heating time is set correctly. As a result, the reliability of the erase operation is improved while the overall process time and excessive overstress on the thermochromic recording medium 1 be reduced.

In a further modification, the transport control unit controls 64 the transport roller 71 such that the thermochromic recording medium 1 enters the nip portion in which the thermochromic recording medium 1 in contact with the heating roller 65 is heated when or after the temperature Tr of the pressure roller passing through the first sensor 68 is detected, has reached a predetermined temperature. This arrangement also improves the reliability of the erase operation, and at the same time minimizes the process time and the adverse influence of excessive loads.

In the second proposal, the transport control unit acts 64 as a process control means and controls the operation of the transport roller 11 based on the temperature Tr of the pressure roller, so that the thermochromic recording medium 1 enters the gap section at a suitable time. In one example, the thermochromic recording medium becomes 1 supplied to the nip portion when the temperature Tr of the pressure roller 67 has reached a predetermined temperature. This arrangement improves the reliability of the immediate Erase operation while preventing excessive stresses on the recording medium to minimize adverse influences. In another example, the timing of transportation is set based on a predetermined preheat time, which is simpler than the previous example to achieve the same effect.

In another example of the second proposal, a second sensor 69 is for detecting the temperature of the heat roller 65 intended. The transport control unit 64 controls the rotation of the transport roller 71 such that the thermochromic recording medium 1 enters the nip section when the temperature of the heat roller 65 passing through the second sensor 69 is detected, has reached a predetermined temperature. The arrangement not only takes into account the temperature of the pressure roller 67 , but also the temperature of the heating roller 65 and ensures the reliability of the erase operation, while the processing time and the influence of excessive stresses on the thermochromic recording medium 1 be made minimal.

In another example of the second proposal, the temperature control unit operates 63 as a preheater and temperature control agent. The temperature of the heating roller 65 is through the temperature control unit 63 is controlled so that the heating roller is heated at a deletion command to the first temperature (eg., 170 ° C), the temperature then during the actual heating of the thermochromic layer 3 of the recording medium 1 at the second temperature (eg 150 ° C). By quickly heating the heating roller 65 to the first temperature, which is greater than the target temperature (ie, the second temperature) upon receipt of the erase command, the startup time of the erase device can be shortened.

The third proposal is a third temperature sensor 81 provided for detecting the ambient temperature outside the extinguishing device. The temperature control unit 83 and the transport control unit 64 , which form the deletion condition control means, control the deletion conditions of the thermochromic recording medium 1 based on the temperature Tr of the pressure roller passing through the first sensor 68 is detected, as well as by the temperature To, by the third sensor 81 is detected. The temperature To is the temperature of the thermochromic recording medium 1 represent. In addition to the temperature of the pressure roller, the temperature of the thermochromic recording medium 1 is taken into account, the setting temperature of the heating roller 65 To select and control, a more accurate temperature control is achieved. As a result, the reliability of the erase operation is improved.

In a modification, the transport control unit controls 63 the transport roller 71 such that the thermochromic recording medium 1 enters the nip portion when the temperature Tr of the pressure roller 67 has reached a predetermined temperature corresponding to the temperature of the thermochromic recording medium 1 is selected and by the ambient temperature, by the third sensor 81 is detected, is represented. The reliability of the erase operation is further improved.

The fourth proposal is a fourth temperature sensor 82 provided the temperature Tm of the thermochromic recording medium 1 detected within the extinguishing device before the surface of the thermochromic recording medium 1 with the heating roller 65 got in contact. In this case, control the temperature control unit 63 and the transport control unit 64 , the erase condition control means, the erase operation based on the temperature Tr of the pressure roller, by the first sensor 68 is recorded; and the temperature Tm of the recording medium 1 passing through the fourth sensor 82 is detected. In this example, the direct measurement of the temperature of the thermochromic recording medium 1 and the temperature Tr of the pressure roller 7 takes into account the setting temperature of the heating roller 5 select. As a result, the reliability of the erase operation is improved.

In a modification, the transport control unit controls 63 the transport roller 71 such that the thermochromic recording medium 1 enters the nip portion when the temperature Tr of the pressure roller 67 has reached a predetermined temperature in accordance with the direct measurement Tm of the thermochromic recording medium 1 is selected. The reliability of the erase operation is further improved.

Thus, a uniform and reliable heating operation becomes within the appropriate extinguishing temperature of the thermochromic layer 3 of the recording medium 1 performed at any state during excessive stresses on the thermochromic recording medium 1 be prevented. That on the thermochromic recording medium 1 Printed image is stably erased without ripples or bumps being formed and without leaving any colors on the recording medium 1 remain. A thermochromic recording medium 1 The size A4 (size of plain paper) is reused many times while the state of the thermochromic recording medium 1 is maintained satisfactorily. As a result, public fears that the destruction of the environment and natural resources as a result of ei of huge paper consumption and waste dumping.

It It should be noted that the heating means does not touch the heating roller or the thermal head is limited but contain any means that are suitable to heat thermochromic recording medium. It can z. B. heating means using laser beams are used. Likewise, the pressure means are not limited to the pressure roller, but contain all the means that are suitable to the thermochromic recording medium to press against the heating means.

Even though the invention is described using only those components was required to complete the construction and operations of the extinguishing device and the rewritable printing apparatus can be explained in the device, if necessary, a feed guide, feed rollers, paper feed sensors, Paper input trays, Eject compartments, exhaust fan be provided.

Claims (19)

extinguishing device for the Use with a thermochromic recording medium comprising: heating for heating the thermochromic recording medium to a quenching temperature or at a quenching temperature, around an image printed on the thermochromic recording medium Clear; a Stress applier, which is arranged on the outlet side of the heating means and on the thermochromic recording medium heated by the heating means to exert a tensile load; in which the stress applying device a cooling area to add the heated thermochromic recording medium cool; and in which the stress applying device the tensile stress on the thermochromic recording medium exerts when the surface temperature of the thermochromic recording medium after erasing in remains a prescribed area. extinguishing device according to claim 1, wherein the stress applying means is a curved transport path is, which extends on the outlet side of the heating means. extinguishing device according to claim 2, wherein the curved transport path has a curved surface a radius of curvature, which is equal to or smaller than 40 mm. extinguishing device according to claim 2 or 3, wherein the curved transport path through a guide is defined, which is a curved surface has. extinguishing device according to claim 4, wherein the guide has one or more grooves extending in the direction of its longitudinal axis extend. extinguishing device according to claim 2 or 3, wherein the curved transport path through a plurality of rollers is defined. extinguishing device according to claim 2 or 3, wherein the curved transport path through a Belt is defined around one or more rollers. extinguishing device according to claim 2 or 3, wherein the curved transport path through a Air flow is defined. extinguishing device according to claim 1, wherein the stress applying means in the direction of gravity is positioned under the heating means. extinguishing device according to claim 1, wherein the stress applying means is a bending transport path is, which extends from the heating means and a slope with has a predetermined angle to the horizontal. extinguishing device according to claim 10, wherein the predetermined angle with respect to Horizontal is at least 30 degrees. extinguishing device according to claim 10 or 11, wherein the bending transport path through a Leadership with a sloped surface is defined. extinguishing device according to claim 12, wherein the guide has one or more grooves extending in the direction of its longitudinal axis extend. extinguishing device according to claim 10 or 11, wherein the bending transport path through a plurality Roles is defined. extinguishing device according to claim 10 or 11, wherein the bending transport path through a Belt is defined around one or more rollers. extinguishing device according to any one of the preceding claims, wherein the stress applying means the tensile stress on the thermochromic recording medium exercises before the surface temperature the thermochromic recording medium to 60 ° C or less has fallen off. Extinguishing device according to one of vorherge The claims claim, wherein the stress applying means exerts the tensile stress on the thermochromic recording medium when the surface temperature of the thermochromic recording medium is below 100 ° C. extinguishing device according to any one of the preceding claims, wherein the stress applying means a cooling property owns to heat remove from the thermochromic recording medium. Rewritable printing device, characterized by: the extinguishing device according to one of the claims 1 to 18 to delete the image printed on the thermochromic recording medium; and a recording unit behind the extinguishing device is positioned to put on the deleted thermochromic recording medium to print a new image.