JPH058536A - Recording device - Google Patents

Abstract

PURPOSE:To provide a recording device wherein recording and deletion of record image can be performed stably and assuredly. CONSTITUTION:A recording device comprises a recording means for record a visible image by giving recording energy for recording the visible image on a record medium and a means for deleting the visible image by giving deleting energy a plurality of times within a record unit of the visible image when the visible image recorded on the record medium is to be deleted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording apparatus for recording a visible image on a recording medium on which a visible image is recorded and erased by heat.

[0002]

2. Description of the Related Art In conventional hard copy recording, an image is formed on a recording medium such as paper from the outside with a visual material such as ink or toner, or in some sense, on a base material such as thermal recording paper. A recording layer is provided and a permanent image is recorded by forming a visible image on this recording layer. However, the rapid increase in the consumption of these recording materials with the construction of various network networks and the spread of facsimiles and copying machines causes problems of natural destruction such as deforestation and social problems such as garbage disposal. In order to deal with these problems, it is strongly required to reduce the consumption of recording material such as reproduction of recording paper. For this problem, a recording material that can be repeatedly recorded and erased has attracted attention.

As a material having such characteristics, a recording material has been proposed which reversibly changes both the transparent state and the cloudy state depending on the temperature applied to the recording material. This recording material has a temperature of T
_{When the} temperature is raised from ₁ to the temperature T ₃ , the transparent state changes to the cloudy state, and the cloudy state is maintained as it is even when the temperature returns to the temperature T ₁ . Then, the temperature of the recording material is raised from the temperature T ₁ to a temperature T ₂ lower than the temperature T _3, and the temperature T _{1 is} again set.
When returned to, the cloudy state changes to a transparent state and the transparent state is maintained. This change can be repeatedly reproduced. A study on deterioration of resolution in repetitive recording when recording with a thermal head using such a recording material has been reported (Proceedings of the 4th Non-Impact Printing Technology Symposium, 3-2, p57 (Showa 6).
2 years)).

[0004]

[Problems to be Solved by the Invention] Conventional repetitive recording /
With an apparatus for recording / erasing on an erasable recording material, when recording / erasing repeatedly, the recording density of the recorded image is lowered, or the unerased portion remains, so that stable and reliable recording / erasing is performed.
There is a problem that the erasing process cannot be performed.

Therefore, the present invention has been made in view of the above problems, and an object of the present invention is to provide a recording apparatus capable of stably and reliably recording and erasing a recorded image.

[0006]

In order to solve the above problems, in the recording apparatus of the present invention, a visible image is recorded and erased by applying recording energy for recording a visible image. A visible image is recorded on the recording medium, and recording means for recording the visible image by applying the recording energy on the recording medium where the visible image is erased by applying the erasing energy. When erasing, a erasing unit is provided for erasing the visible image by applying erasing energy a plurality of times within the recording unit of the visible image.

[0007]

According to the recording apparatus of the present invention, recording energy is applied to a recording medium to record a visible image, and the visible image is recorded. When the visible image is erased, the visible image is erased in a recording unit. The visible image is erased by applying energy a plurality of times, and the visible image is recorded and erased.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

In the embodiment described below, an energizing pulse for driving the heating resistor of the thermal head is generated twice within one dot forming cycle, and in response to the energizing pulse, recording or erasing of a visible image is performed. The energy to be applied is applied twice in a single dot formation cycle.
In addition, one dot formation cycle is 4 ms, pulse energization time is 1 ms for mark dots, pulse energization time is 0.7 ms for space dots, and thermal head drive voltage is 1
It is 6V.

FIG. 1 shows the energizing pulse (upper stage) of the thermal head, the heating resistor and the temperature of the recording medium (middle and lower stages) when recording / erasing image points. Mark dots (recording) are shown on the left side and space dots (erasing) are shown on the right side. In this embodiment, two energizing pulses are provided within one dot forming time as shown in the upper part of FIG.
A recording material that changes its state between a transparent state and a cloudy state in accordance with the applied thermal energy is recorded on a recording medium provided on the surface of the base material. The energizing pulse to the mark dot or the space dot has the same voltage value and the energizing time is changed. In the case of mark dots, the first pulse heats the heating resistor to a temperature at which the recording medium can be recorded on the recording medium, that is, a temperature at which the recording medium becomes cloudy. The recording medium in contact with the heating resistor is heated to the clouding temperature by the heat energy flowing from the heating resistor. When the power is turned off, the temperature of the heating resistor drops to a temperature that does not change the recording medium. Accordingly, the temperature of the recording medium also drops to around room temperature, but the portion to which heat is applied becomes cloudy. The second pulse is also energized for the same time as the first pulse. The temperature of the resistance heating element rises again. As for the temperature of the heating resistor, the highest temperature reaches a little higher than that at the time of the first energization because the heat is accumulated by the first pulse. The recording medium moves by the effective heating length of the heating resistor (corresponding to the dot pitch of the visible image) in the time of one dot forming cycle. Further, since the effective heating area of the heating resistor corresponds to the dot area forming the visible image, the minimum 1 / th of the area of the recording medium on which the mark dot is formed is formed.
In region 2, heat is applied twice by the first heat generation and the second heat generation. Therefore, when the second heating resistor generates heat,
The temperature rises from a slightly warmer state than the initial state. By the second heating, the area of the recording medium that contacts the heating resistor again rises to the clouding temperature. Therefore, half of the area of the formed mark dot undergoes whitening twice and the mark dot is formed. In the case of the space dot, the pulse energization time is shorter than that of the mark dot, so that the temperature of the heating resistor becomes the maximum temperature at which the cloudy image on the recording medium is made transparent. Also in the case of space dots, half of the area of the space dots formed in the same manner as described for the formation of the mark dots is formed through the transparency twice.

As is clear from the above description, in the recording method according to the present invention, energy capable of recording or erasing a visible image on the recording medium even once is applied twice in one dot forming cycle. It is characterized in that it is applied to. The recording layer of the recording medium used in this example reversibly changes to both cloudy and transparent states by the applied thermal energy, but as shown in the lower part of FIG. . When the maximum temperature of the recording layer of the recording medium reaches these temperature regions, it becomes cloudy or transparent. If the heating temperature of the heating resistor of the thermal head is controlled so that the maximum temperature of the recording medium is close to the lower limit temperature of each state, the influence of the heat on the recording layer surface of the recording medium contacting the heating resistor Is reduced and the repeated use life of the recording medium can be extended. However, it is difficult to accurately control the temperature of the heating resistor, and temperature variations generally occur. Further, the cloudy state and the transparent state do not change in a binary manner but have a transition region as shown in FIG. In this area, the density of dots is likely to change in an area in which a cloudy state and a transparent state are mixed. Therefore, for example, when the heating resistor is driven so that the maximum temperature of the recording medium is close to the lower limit temperature of each state according to the conventional recording method of forming mark dots according to one energizing pulse without multiplexing the recording energy. The density of the mark dots to be formed is not constant, and in some cases mark dots having an extremely low density are formed. As described in the above embodiment, in the recording method according to the present invention, since the energy for recording a visible image on the recording medium or the energy for erasing the visible image is multiplexed to form dots, the maximum temperature of the recording medium is increased. Even if the heating resistor is driven so that the temperature becomes close to the lower limit temperature of each state, in the case of mark dot formation, dots of sufficient density are erased twice by the effect of erasing twice in the case of space dots. Even if there are mark dots, the erasure is completed completely.

Further, the present inventors investigated the relationship between the clouding temperature and the repeated use life of the cloudy image, and obtained the findings shown in FIG. An image density was measured by heating a recording medium which was made transparent as an initial state with a heat roller rotating at a convergence of 40 mm / s and having a constant temperature, and the image density was measured by repeating this process. As the heat roller temperature, T _w1 , T _w2 and T _w3 in the white turbid saturation concentration region shown in FIG. 2 were used. As is clear from FIG. 3, the higher the clouding temperature, the greater the change in the cloudy density as the number of repetitions increased. Therefore, it is desirable to record with the minimum energy to obtain the required concentration.

In the case of recording and erasing a visible image by heating a recording medium using a thermal head, the time for applying heat to the recording medium is extremely short, such as several ms or less, as compared with a heat roller, and Since it is necessary to raise the temperature of the recording layer of the recording medium to the same temperature in such a short time, the temperature of the heating resistor of the thermal head that contacts the surface of the recording medium becomes several hundreds of degrees. When a high-temperature heat source is contacted for an extremely short time in this way, the closer to the contact side of the heat source (heating resistor), the higher the temperature and the temperature gradient in the thickness direction of the recording medium, as schematically shown in FIG. It is known that the temperature is steep, the temperature is lower and the temperature gradient becomes gentler as the distance increases. Therefore, since a temperature difference occurs in the recording layer, the temperature of the entire recording layer returns to room temperature after the heat supply from the heating resistor is completed, but the temperature reached by each recording portion is different. When performing cloudy recording, the temperature of each part of the recording layer may be set to be equal to or higher than the minimum clouding temperature as shown in FIG. Are different. When the clouding temperature is too high, the repeated life becomes short as shown in FIG. On the other hand, when the thickness of the cloudy region in the recording layer is thin, a sufficient cloudy density cannot be obtained. Therefore, it is desirable that the clouding temperature be as low as possible and that the temperature gradient in the recording layer be gentle.

In the recording method of the present invention, as described above, heat is multiplexed and applied to the recording medium. Therefore, the temperature of the applied heat may be lower than that of the conventional non-multiplexed recording method, and the cycle life is long. Is also advantageous.

Next, using the recording method according to the present invention, FIG.
An example in which overwrite recording is performed on the recording medium exhibiting the reversible state change shown in FIG. The overwrite recording operation in this embodiment will be described with reference to FIG. 5 by showing an example in which the character "L" is overwritten on the character "I". A feature of this recording is that electricity is applied not only to mark dots forming an image but also to space dots not forming an image. First in Figure 5
As shown in (a), the character "I" is recorded on the rewritable recording medium. When the character "L" is overwritten and recorded, the process of FIG. 5B is performed. A heating resistor row 2 of a thermal head (not shown) is in contact with the rewritable recording medium 1, and the rows of heating resistors are arranged so as to be perpendicular to the recording direction. The heating resistors are provided in a sufficient number to record the width of the recording medium.
3 is a part of the already recorded image "I" and 4 is a part of the new image "L". 5 is a part of the erased but increased "I", and 6 is a rerecorded dot part.
When recording on a rewritable recording medium, the heating resistor corresponding to the pixel of interest: mark dot, regardless of the existing image,
It suffices to raise the temperature of the recording medium to the cloudy temperature range. Also in the case of erasing, the heating resistor corresponding to the pixel of interest: space dot may be raised to a temperature at which the recording medium is raised to the transparent temperature range, regardless of the existing image. in this way,
When a new image 4 is recorded by selectively heating the heating resistors by the recording method according to the present invention while transporting the rewritable recording medium 1 under the heating resistor row 2 of the assumed thermal head in the arrow direction. At the same time, so-called overwrite recording, which erases the old image 3, was realized.
The recording layer of the rewritable recording medium used here is about 60
It becomes transparent at ℃ ~ 90 ℃, the cloudiness is saturated at about 95 ℃ or more. The upper limit of the heating temperature is determined by the heat resistance of the protective layer or recording layer provided on the recording layer. This recording medium has a temperature of about 150 ° C. It goes without saying that the recording apparatus of the present invention can be applied to the case where the visible image recording and the visible image erasing are independently performed on the recording medium.

In the above embodiments, the white turbid state of the recording layer is used as the recorded image, but the white turbid state may be used as the background color and the transparent state may be used as the recorded image. Further, the recording material to which the present invention can be applied is not limited to the materials of the examples, and can also be applied to a recording material using a leuco dye that exhibits a reversible color tone change only by controlling thermal energy as a color source.

Further, the example in which the thermal head recording means is used as the recording means has been described, but in addition to this, it is possible to use a recording means such as a laser recording means capable of applying heat to the recording medium by photothermal conversion. Of course.

According to the present invention, recording and erasing of a visible image can be performed stably and reliably. Further, the image can be rewritten without erasing the already formed image in advance. Further, the image can be rewritten regardless of the image pattern or the pattern position. Furthermore, it has become possible to downsize and simplify the device. It is possible to record and erase in a pixel unit on an arbitrary portion of the recording medium. Further, it has become possible to save the resources of the recording medium and reduce the printing cost.

[0019]

As described in detail above, according to the recording apparatus of the present invention, visible images can be recorded and erased stably and reliably.

[Brief description of drawings]

FIG. 1 is a diagram showing an energization pulse supplied to a thermal head of a recording apparatus according to an embodiment of the present invention, a temperature change of an energized heating resistor, and a temperature change of a recording medium to which heat is applied.

FIG. 2 is a diagram for explaining transition temperature ranges of both a cloudy state and a transparent state.

FIG. 3 is a diagram showing a change in white turbidity concentration during repeated white turbidity.

FIG. 4 is a diagram schematically showing a heat distribution in a thickness direction of a recording medium when heat is applied by a thermal head.

FIG. 5 is a diagram showing how overwrite recording is performed by the recording method of the present invention.

[Explanation of symbols]

1 recording medium, 2 heating resistor array, 3 part of recorded image, 4 new image part, 5 part of erased image, 6 re-recorded dot part

Claims (1)

Claim: What is claimed is: 1. A visible image is recorded by applying recording energy for recording a visible image, and the visible image is formed by applying erase energy for erasing the visible image. Recording means for recording the visible image by applying the recording energy for recording the visible image to the recording medium to be erased, and the recording medium for erasing the visible image recorded on the recording medium. An erasing unit for erasing the visible image by applying the erasing energy a plurality of times within a recording unit of a visual image.