JPH08305228A - Optical color erasing device - Google Patents

Abstract

PURPOSE: To prevent the production of growing yellowish and scorching by discharging a recording medium without substantially erasing color in the case where an especially dark recording medium is sucked. CONSTITUTION: An optical color erasing device comprises paper feed rollers 18, 20 for conveying a recording medium S, a detecting means 50 for detecting the depth of recording of the recording medium S, and color erasing halogen lamps 28, 30 disposed in the midway of a conveying path for erasing the color of recording on the recording medium, whereby if recording of the recording medium S is lighter than a designated density, color erasing is performed by the halogen lamps 28, 30 and the recording medium S is discharged, and if recording of the recording medium S is darker than the designated density, the halogen lamps 28, 30 are switched off, and the recording medium S is discharged without color erasing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical system capable of erasing the recording on a recording medium recorded with a recording material containing an optically erasable dye, such as aqueous ink, oil-based ink, toner and the like. Erasing device.

[0002]

2. Description of the Related Art In recent years, near-infrared erasable dyes have attracted attention as dyes for recording agents used in various printers, copying machines and the like. This is because a recording medium such as a recording paper recorded with a recording agent containing such a dye can be reused by repeating recording and erasing, and can contribute to the protection of forest resources. The near-infrared color erasable dye is disclosed in, for example, JP-A-4-362935.

Japanese Unexamined Patent Publication (Kokai) No. 6-175537 discloses a sheet feeding cassette as a lightweight and compact erasing device capable of efficiently erasing optically erasable toner and having a short erasing time per sheet. There has been proposed an erasing device including a paper feed roller, a guide member, a light source, a concave mirror that collects light emitted from the light source, a paper discharge tray, and a housing.

Further, the applicant of the present application has previously filed Japanese Patent Application No. 6-19.
In 9653, a new optical erasing device is proposed. In this optical erasing device, erasing light sources are arranged above and below the conveying path, and the erasing light source provided on the upper side of the conveying path is different from the erasing light source provided on the lower side of the conveying path. Staggered in the direction. It was also found that it is preferable to apply warm air to the recording medium at the same time as irradiating the recording medium with the erasing light source. According to this optical erasing device, it is possible to continuously erase the recording medium in a short time with a simple mechanism.

[0005]

One of the problems of the above optical erasing device is that the erasing action differs depending on the density of recording on the recording medium. When the recording on the recording medium is light, the energy of the erasing light source may be small, and when the recording on the recording medium is dark, the energy of the erasing light source needs to be large. Since the recording medium has various shades and the shade is unpredictable, the optical erasing device is usually set so as to be able to erase a dark record.

However, although there is no problem in the case of a paper that has been printed or copied normally, there are some papers that are particularly dark or that are entirely solid and completely black. In the case of such a paper, an optical erasing device which is normally set to erase a dark record has too much heat and light energy for erasing, causing a yellowing of the paper or a local defect. There is a problem of overheating and burning.

It is an object of the present invention to eject a recording medium without substantially decoloring it when a particularly dark recording medium is inhaled so as to prevent yellowing or burning. It is to provide an erasing device.

[0008]

SUMMARY OF THE INVENTION An optical erasing apparatus according to the present invention comprises a conveying means for conveying a recording medium along a predetermined conveying path, and the density of recording on the recording medium sucked from the entrance of the conveying path. And a decoloring light source provided in the middle of the conveying path for decoloring the recording on the recording medium, and the recording on the recording medium may be lighter than a predetermined density by the detecting unit. When it is detected, the recording medium is erased by the erasing light source and the recording medium is discharged, and when the detection means detects that the recording on the recording medium is darker than a predetermined density. It is characterized in that the recording medium is discharged without erasing the recording on the recording medium by the erasing light source.

[0009]

According to this structure, the density of the recording of the recording medium sucked is detected, and when it is detected that the dark recording medium is sucked, the erasing of the recording of the recording medium is performed by the erasing light source. The recording medium is ejected without performing. by this,
Prevents yellowing and scorching even when a particularly thick recording medium is inhaled. On the other hand, when it is detected that a light recording medium (including a relatively dark print in this case) is inhaled, the recording medium is erased by the erasing light source. Discharge. As a result, desired erasing can be performed safely and reliably.

In the above optical erasing apparatus, the detecting means comprises a light emitting means for irradiating the recording medium with light and a light receiving means for receiving the light reflected by the recording medium. The rate may be detected as a rate. In this case, the density of recording on the recording medium can be detected according to the desired density.

The light receiving means may be composed of a CCD image sensor. In this case, the density of recording on the recording medium can be detected wholly or partially on the recording medium, and a standard CCD image sensor can be used. A platen is provided on the opposite side of the conveying path from the detecting means, and when the platen is white, the platen portions on both sides of the recording medium are erroneously detected as black recording medium as compared with the black platen. Can be prevented.

The light emitting means emits light having a wavelength capable of erasing the recording on the recording medium, and is used for detecting the light and shade of the recording on the recording medium and as a preliminary erasing means of the erasing light source. Can be done. According to this configuration, the light emitting means acts as the preliminary erasing means, and the recording medium is subjected to the erasing action by the preliminary erasing means and the erasing light source.
Even if the recording medium is hard to be erased, it is easier to surely erase the color.

The provision of the preliminary erasing means is not limited to the structure described in claim 1, and the conveying means for conveying the recording medium along the conveying path and the erasing means provided in the middle of the conveying path. It is applied to an optical decoloring device provided with a light source for use. Also in this case, since the recording medium is subjected to the erasing action by the preliminary erasing means and the erasing light source, even if the recording medium is hard to be erased, it is easier to surely erase the color.

Further, in order to apply warm air to the recording medium, air blowing means for blowing air to the erasing light source can be provided. According to this configuration, by applying warm air to the recording medium, the decoloring action is further enhanced.

Further, the apparatus has a power supply means for supplying power to the erasing light source, and when the detecting means detects that the recording on the recording medium is light, the power supplying means supplies the erasing light source with light. A configuration may be adopted in which power is supplied, and when the detection unit detects that the recording on the recording medium is dark, the power supply unit stops the supply of power to the erasing light source. In this case, the power may be stopped at least until the recording medium is ejected. According to this configuration,
By detecting the density of recording on the recording medium and controlling the power supply means, the erasing light source is allowed to pass through only when the recording medium having a particularly high density is sucked.

The conveying means includes a step motor, and further has a counter for counting the number of steps from when the recording medium is sucked to when the recording medium is conveyed to the position of the erasing light source. When it is detected that the recording is dark, the power supply is stopped only when the recording medium passes the position of the light source for erasing. by this,
When a dark recording medium is inhaled, the color erasing light source is allowed to pass through, and the action stop time of the color erasing light source is shortened as much as possible so that there is no delay when the next density recording medium is inhaled. To be able to perform the erasing action.

Further, the conveying means includes a step motor, and further has a counter for counting the number of steps from when the recording medium is sucked to when it is conveyed to the position of the detecting means, and the recording medium is the detecting means. It is also possible to adopt a configuration in which the detection means is activated only when the position is. Further, a configuration is provided which includes means for generating an enable signal for validating the output of the detecting means when the recording medium is at the position of the detecting means, and a logic circuit for receiving the output of the detecting means and the enable signal. Can also be With these configurations, it is possible to prevent erroneous detection when the recording medium is not at the position of the detecting means.

When the detection means detects a dark portion of the recording medium, the erasing light source is turned off when the dark portion of the recording medium passes through the erasing light source, and the other portions of the recording medium. It is also possible to adopt a configuration in which the erasing light source is turned on when this portion passes through the erasing light source. In this case, the variable speed motor can be driven at a high speed to convey the recording medium when the dark recording portion of the recording medium passes through the erasing light source. In this way, only the dark portion of the same recording medium is not erased, but the other portions are erased.

[0019]

Embodiments of the present invention will now be described in detail with reference to the accompanying drawings. FIG. 1 is a schematic cross-sectional view of an optical decoloring device according to the present invention, and FIG. 2 is a schematic plan view along a conveyance path of a recording medium of the optical decoloring device shown in FIG.

In FIGS. 1 and 2, the optical erasing device 1 is used.
0 has a frame 12, a hopper 14 is attached to one end of the frame 12, and a stacker 16 is provided to the other end of the frame 12. In the frame 12, paper feed rollers 18 and 20 and a discharge roller 22 are arranged, and a conveyance path P for the recording medium is formed along these rollers. Each roller includes a nip roller. A paper feed sensor 24 is provided in front of the paper feed roller 18, and a discharge roller 22 is provided.
After that, there is the discharge sensor 26.

In the hopper 14, a recording medium S such as a copy paper which has been printed or copied and whose record can be erased is inserted. The recording on the recording medium S is performed as characters, figures, etc. by using a recording material containing an optically decolorizable dye, for example, water-based ink, oil-based ink, toner or the like. The recording media S are taken out one by one from the hopper 14 and conveyed along a predetermined conveyance path P.

An erasing section D is provided in the frame 12 between the paper feed roller 20 and the discharge roller 22. The erasing section D includes halogen lamps 28 and 30 as erasing light sources. The halogen lamp 28 is located above the transport path P,
The halogen lamp 30 is located below the transport path P. Further, as shown in FIG. 2, in the erasing section D, linear transport guides 32 are provided above and below the transport path P (only the lower one is shown in FIG. 2), and each linear transport guide 32 is provided. Comprises a plurality of rods extending in the transport direction and arranged parallel to the width direction. Further, wire meshes 34 are provided above and below the linear conveyance guide 32. The wire netting 34 prevents dust and foreign matter from entering the halogen lamps 28 and 30.

The recording medium S is guided by the linear conveyance guide 32 in the erasing section D. The front end portion and the rear end portion of the linear transport guide 32 are respectively curved up and down in order to smoothly receive or eject the recording medium S. The material of the linear body may be metal such as wire, or may be made of heat resistant plastic.

A halogen lamp 28 as a light source for erasing,
30 are provided on the upper side and the lower side of the linear conveyance guide 32, respectively. The halogen lamps 28 and 30 have a length substantially corresponding to the size of the recording medium S to be erased in the width direction, and are arranged so as to extend at right angles to the traveling direction of the recording medium S. The upper and lower halogen lamps 28 and 30 are preferably arranged so as to be displaced from each other in the traveling direction of the recording medium S. Halogen lamps 28 and 30 are 50 to 500 each
W is suitable and emits near infrared rays in the wavelength range of 600 to 900 nm. It is also possible to use a metal halide lamp instead of the halogen lamp. Further, it is also possible to use a flash lamp which emits light intermittently instead of being continuously lit in this way.

The halogen lamps 28 and 30 are provided with a partition plate 36.
It is surrounded by. The partition plates 36 are intake ducts 36a, 3
6b, and intake fans 38 and 40 are arranged in the intake ducts 36a and 36b, respectively. The partition plate 36 has an exhaust duct 36c, and the frame 12 has an exhaust port 12a. The exhaust fan 42 is arranged at the exhaust port 12a. In this way, the air is forced against the halogen lamps 28 and 30 by the intake fans 38 and 40 so that the generated hot air strikes the recording medium S.

A temperature sensor (not shown) for detecting the temperature of the warm air applied to the recording medium S is provided on the outer wall of the partition plate 36.
Is attached, and the temperature of the hot air applied is continuously detected, and the temperature of the hot air applied to the recording medium S is maintained at 100 ° C. or higher and 240 ° C. or lower. Further, by detecting the temperature with this temperature sensor, when the temperature of the warm air reaches an appropriate value, a color erasing start switch (not shown) is turned on and the halogen lamps 28 and 30 are turned on to emit light. The conveyance of the recording medium S can be started after reaching the predetermined temperature, or the conveyance speed of the recording medium S can be changed according to the detected temperature of the hot air.
For example, at 60 ° C, 1PPM (A4 sheet: 1 sheet /
Min), the conveying speed can be increased according to the temperature rise, as in 2PPM at 140 ° C. or higher.

The exhaust fan 42 forcibly exhausts air, warm air, etc. inside the apparatus. In addition, if the recording medium S is the erasing part D
If stopped inside, halogen lamps 28, 3
0 and the intake fans 38 and 40 are immediately stopped, and only the exhaust fan 42 is operated to prevent the recording medium S stopped inside the apparatus from being overheated. When it is detected that the recording medium S has stopped, the exhaust fan 42 can be operated at high speed to promote cooling of the inside of the apparatus and prevent overheating of the recording medium S.

The recording medium S is heated by warm air, and at the same time, is irradiated with near infrared rays by the halogen lamps 28 and 30, and the recording on the recording medium S is erased. The color-erased recording medium S is discharged from the discharge roller 22 after exiting the linear conveyance guide 32.
Is sent to the stacker 16. At that time, the discharge sensor 2
6 optically detects whether or not a jam has occurred on the recording medium S, confirms that the recording medium S has exited the erasing section D, and removes the recording medium S from the decolorizing brush (not shown). Static electricity is removed.

Further, in the present invention, a recording density detector / preliminary erasing section E is provided in front of the erasing section D. The detection unit / preliminary erasing unit E includes an optical detection unit 50 and a white platen 52. As shown in FIG. 3, the optical detecting means 50 includes a light emitting element 54 for irradiating the recording medium S with light and a light receiving element 5 for receiving the light reflected by the recording medium S.
6 is used to detect the density of recording on the recording medium S as the light reflectance. The light receiving element 56 is a CCD image sensor in which CCD elements are arranged along a reading area wider than the width of the recording medium S to be detected.

The white platen 52 is also longer than the width of the recording medium S to be detected. If you use the black platen,
Since the optical detecting means 50 erroneously detects the black platen portions on both sides of the width of the recording medium S as if there is a black recording medium, it is preferable to use the white platen 52 in the present invention.

The optical detecting means 50 detects the density of the recording on the medium S according to the same principle as in the case of image reading by a copying machine. The light emitting element 54 is an LE for the purpose of detection only.
Although a D lamp, a fluorescent lamp, or the like can be used, a halogen lamp or a metal halide lamp is preferably used in the same manner as the halogen lamps 28 and 30 as the main erasing light source for erasing the recording.

As shown in FIG. 1, the optical detecting means 5
Outputs of 0, the paper feed sensor 24, the discharge sensor 26, and other sensors are input to the control unit 58. The control means 58 is a halogen lamp 28, 30, an optical detection means 5
0, the drive motors (not shown) for the paper feed rollers 18, 20 and the discharge roller 22, and the intake fans 38, 40 and the exhaust fan 42.

FIG. 4 is a block diagram of an apparatus including the control means 58. The control means 58 is mainly composed of a CPU 60, and further has a detection circuit 62 which receives the output of the light receiving element 56
It includes a power supply unit 64 for controlling the power supply to the halogen lamps 28, 30, a counter 66, and a motor control unit 68. FIG. 4 shows the drive motor 70 for the paper feed rollers 18, 20 and the discharge roller 22.
Variable speed motors and step motors are used as
It is controlled by the motor control unit 68.

FIG. 5 is a diagram showing an example of a control flow chart of the optical erasing apparatus 10. In this example, it is assumed that the drive motor 70 is driven at a constant speed. In step 71, the recording medium S (hereinbelow, simply referred to as paper) made of copied paper or the like is sucked from the hopper 14 one by one, and is conveyed along the conveyance path P. In step 72, the optical detecting means 50 detects the density of the recording on the paper. That is, the light emitting element 54 emits light,
The light receiving element 56 reads the light reflectance. The light receiving element 56 is composed of a CCD image sensor, and performs detection while scanning in the width direction of the paper in a known manner.

Further, the light emitting element 54 radiates heat and emits near-infrared rays to erase the recording on the paper, and the preliminary erasing section E is formed with respect to the original erasing section D. There is. In step 73, the density of recording on the paper is determined. An example of the output (sensor output) of the optical detecting means 50 is shown in FIG. The sensor output is represented by the reflectance of light. The higher the reflectance, the closer it is to white, and the smaller the reflectance, the closer it is to black. T ₀ is a threshold value for determining the density of recording.

Here, the paper is, for example, a used copy paper, and usually includes a recording portion such as characters. The output of the recording portion of the character or the like exceed Suresshodo value T ₀ (smaller than Suresshodo value T ₀₎ appears on the black side. However, even if the recorded portion of characters and the like is black, the proportion of the black portion occupying the unit area of the paper is small, and the detected value exceeds the threshold value T ₀ and appears on the black side sporadically. In the present invention, the detected value that appears on the black side by itself exceeding the threshold value T ₀ is not determined to be darker than the predetermined density.

On the other hand, the paper is entirely black,
Or if part of the paper is completely black,
As shown in FIG. 6B, the threshold value T₀Beyond
The detected values appearing on the black side become continuous. Book
In the invention, the threshold value T ₀Appears on the black side beyond
For example, if there are 10 consecutive detected values, or
Threshold value T out of 30 samples₀Over black
The detection value appearing on the color side has exceeded 60%
In this case, it is determined that the density is higher than the predetermined density.

If the result of the determination in step 73 is NO, that is, if it is determined that the recording on the paper is lighter than the predetermined density (that is, normal copied paper), the routine proceeds to step 74, where the halogen lamps 28 and 30 are turned on. Determine whether or not The halogen lamps 28 and 30 (and the intake fans 38 and 40 and the exhaust fan 42) are turned on before the start of sheet conveyance as described above prior to step 71. Therefore, the determination in step 74 is normally yes, but it is no when step 78 described later is passed. If the determination in step 74 is no, step 75
Then, the halogen lamps 28 and 30 are turned on. The halogen lamps 28 and 30 are turned on and off by supplying power by the power supply means 64 in FIG. 4 or by stopping the supply of power.

The sheet is conveyed along the conveying path P, and is subjected to the erasing action of the light emitting element 54 in the preliminary erasing section E, and then reaches the main erasing section D to be further erased. Here, the paper (recording medium S) is preliminarily decolored, then heated to a high temperature by applying warm air (100 ° C. to 240 ° C.), and the halogen lamps 28 and 30 emit near-infrared rays having a predetermined wavelength. Since light (wavelength 600 to 900 nm) is irradiated, the recording is surely erased.

The paper (recording medium S) is finally discharged,
The ejection sensor 26 detects the ejection of the sheet (step 7).
6). If the discharge sensor 26 does not detect the discharge of the paper at an appropriate time, it is determined that a jam or the like has occurred, and another process (not shown) is performed. Step 73
If YES, the process proceeds to step 77 to end the preliminary erasing. That is, the light emission of the light emitting element 54 is stopped. However, when the preliminary decoloring is not so strong, it may not be necessary to stop the light emission of the light emitting element 54. Then proceed to step 78 and the halogen lamps 28, 30
Turn off. In this way, when it is detected that the recording on the paper (recording medium S) is darker than the predetermined density,
The paper is discharged without erasing the recording of the paper by the halogen lamps 28 and 30 (step 76).

FIG. 7 is a diagram showing a modification of the block diagram of the apparatus shown in FIG. 4, and generally includes substantially the same members as in FIG. In FIG. 7, an AND logic circuit 80 is provided between the detection circuit 62 receiving the output of the light receiving element 56 and the CPU 60.
Is provided. Further, the drive motor 70 is a step motor, and is provided with a counter 66a that counts the number of steps from when the recording medium S is sucked to when the recording medium S is conveyed to the position of the optical detecting means 50.

The output of the counter 66a is input to the AND logic circuit 80. Therefore, the counter 66a is a means for generating an enable signal for validating the output of the optical detection means 50 when the recording medium S is at the position of the optical detection means 50. This prevents a malfunction when the recording medium S is not at the position of the optical detecting means 50.

FIG. 8 is a flow chart in which the output of the counter 66a activates the optical detecting means 50 only when the recording medium S is at the position of the optical detecting means 50. In step 81, the sheet is sucked, and in step 82, the sheet is detected by the detection unit (optical detection means
Position) is determined. In this case, after the paper reaches the paper feed sensor 24, the optical detection means 50
Count the steps of the stepper motor until reaching. If yes, in step 83, the density of the recording is detected by the optical detecting means 50 according to the method described above. In step 84, it is determined whether or not the paper has passed the detection portion (the position of the optical detection means 50). If the result is YES, the optical detection means 50 ends the detection of the density of the recording. Even when the detection of the light and shade of the recording by the optical detecting means 50 is completed, the light emitting element 54 continues to emit the near infrared light, and the preliminary decoloring described above can be performed.

FIG. 9 is a diagram showing another example of control changes.
The drive motor 70 is a variable speed motor, and when it is detected that the recording on the recording medium is dense, the variable speed motor is driven at a high speed to eject the recording medium. That is,
In step 91, the paper is sucked in, and in step 92, the density of the recording on the paper is detected. If the result is NO, it is determined that the recording on the recording medium is a normal printing paper, and the halogen lamps 28, 30 erase the color. Is performed (the halogen lamps 28 and 30 are turned on). Then, the routine proceeds to step 93, where it is judged whether the paper is ejected. The ejection of the sheet is detected by the ejection sensor 26 as described above.

If the result of the determination in step 92 is YES, it is determined that the recording on the recording medium is dark and special black paper, and in step 94 the halogen lamp 28,
30 is turned off, and the process proceeds to step 95 to issue a high speed conveyance command. Therefore, the drive motor 70 is driven at a high speed, and the paper passes through the erasing section D immediately. Then, the routine proceeds to step 96, where it is judged whether or not the paper is discharged. When the paper is discharged, the halogen lamp 28,
Turn on 30. As described above, after the halogen lamps 28 and 30 are turned off in step 94, the halogen lamps 2 and 30 are turned off as soon as the paper passes through the erasing section D.
It is better to turn on 8 and 30 to prepare for erasing the next paper. For this reason, it is preferable that the power is stopped at least until the recording medium is discharged, and if possible, the halogen lamps 28 and 30 are turned on after the sheet has passed through the erasing section D and before the recording medium is discharged. Good to do.

FIG. 10 is a diagram showing another modification of the control. The drive motor 70 is a step motor and a variable speed motor. A counter 66a (see FIG. 7) that counts the number of steps is provided. In this case, as shown in FIG. 11, the paper (recording medium S) is
In this embodiment, a portion S having a high recording density is provided in a part in the sheet conveying direction, and only the portion S having a high recording density is not erased, and the other portions are erased. Note that the portion S where the recording density is high is not divided into one place.

In step 101, the sheet is inhaled, and in step 102, the density of recording on the sheet is detected. If the result is NO, the step of NO in step 107 is performed, and the halogen lamps 28 and 30 perform the erasing action (halogen lamp 2
8 and 30 are turned on).

If YES in step 102, it is determined that the recording medium has a dark recording portion B, and the process proceeds to step 103 to set the flag to 1. Then, the routine proceeds to step 104, where it is judged whether or not the counter is turned on, and further proceeds to step 105 to turn on the counter. Therefore, in the next cycle, step 1
The determination of 04 is YES, and the length of the dark recording B portion of the recording medium is counted as the number of steps of the step motor.

When the portion of the dark recording B of the recording medium passes through the optical detecting means 50, the judgment at step 102 becomes NO, and since the flag 1 has already been set, the judgment at step 107 becomes YES. Then step 108
Then, the counter is turned off, and the process proceeds to step 109 to determine whether the portion of the dark recording B of the recording medium has passed the erasing portion D, and further proceeds to step 110, the portion of the dark recording B of the recording medium. Determines whether the sheet is passing the erasing section D. If the determination in step 109 is NO and the determination in step 110 is YES, the dark recording B on the recording medium
Since the part of is approaching the erasing part D, step 111
Then, the halogen lamps 28 and 30 are turned off and the portion of the dark recording B of the recording medium is discharged so as not to be substantially erased.

When the portion of the dark recording B of the recording medium passes the erasing portion D, the judgment in step 109 becomes YES, and the process proceeds to step 113, in which the halogen lamps 28, 30.
Is turned on, so that the portion following the portion of the dark recording B of the recording medium is erased. Then, the routine proceeds to step 113, where the flag is reset to 0. Therefore, if there is a second dark recording portion B on the same recording medium, such portion is prevented from being erased again in the same manner as described above.

FIG. 12 is a diagram showing another modification of the control. This example is quite similar to the example of FIG. 10, except that step 114 is provided after step 111. That is, when the dark recording portion B of the recording medium approaches the color erasing portion D, the halogen lamps 28 and 30 are turned off in step 111, and the driving motor 70 is set in step 114.
Is driven at a high speed, and the portion of the dark recording B of the recording medium is discharged at a high speed so as not to be substantially erased.

[0052]

As described above, according to the present invention, when the recording medium contains a relatively dark recording, the recording medium is discharged without erasing. It is possible to prevent the recording medium including the deep recording from being yellowed or scorched, and it is possible to surely erase the color of the erasable ordinary printing paper or copy paper.

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing an embodiment of an optical decoloring device of the present invention.

FIG. 2 is a plan view of a lower part of a conveyance path of a recording medium of the optical erasing device of FIG.

FIG. 3 is a schematic cross-sectional view showing a light / dark detection unit / preliminary erasing unit of the recording of FIG.

FIG. 4 is a block diagram of an apparatus including a control unit of the optical erasing apparatus of FIG.

5 is a diagram showing an example of a flow chart of control of the optical decoloring apparatus of FIG.

FIG. 6 is a diagram showing an example of sensor outputs of FIGS. 1 and 3;

FIG. 7 is a diagram showing a modified example of FIG.

FIG. 8 is a diagram showing a modification example of the control of FIG.

FIG. 9 is a diagram showing another variation of the control of FIG.

FIG. 10 is a diagram showing another variation of the control of FIG.

FIG. 11 is a diagram showing an example of a recording medium having a particularly dark portion in the middle.

FIG. 12 is a diagram showing still another modification example of the control of FIG. 5.

[Explanation of symbols]

 14 ... Hopper 16 ... Stacker 18, 20 ... Paper feeding roller 22 ... Ejection roller 28, 30 ... Halogen lamp 36 ... Partition plate 38, 40 ... Intake fan 42 ... Exhaust fan

Claims (14)

[Claims] 1. A recording medium (S) is conveyed to a predetermined conveying path (P).
Means for carrying along (18, 20, 22, 70)
A detection means (50) for detecting the density of recording on the recording medium sucked from the entrance of the conveying path; and an erasing light source provided in the middle of the conveying path for erasing the recording on the recording medium. (28, 30), and when the detection means (50) detects that the recording on the recording medium (S) is lighter than a predetermined density, the erasing light source (28, 30) causes the recording medium. When the recording means (50) detects that the recording on the recording medium (S) is darker than a predetermined density, the erasing light source (28,
An optical erasing device characterized in that the recording medium is discharged without erasing the recording on the recording medium according to 30). 2. The detecting means (50) is a recording medium (S).
A light emitting means (54) for irradiating the recording medium with a light and a light receiving means (56) for receiving the light reflected by the recording medium, wherein the light and shade of the recording on the recording medium is detected as the light reflectance. 1. The optical decoloring device according to 1. 3. The optical erasing device according to claim 2, wherein the light receiving means (56) is composed of a CCD image sensor. 4. The optical erasing device according to claim 2, wherein a platen (52) is provided on the opposite side of the conveying path from the detecting means, and the platen is white. 5. The light emitting means (54) emits light having a wavelength capable of erasing the recording on the recording medium to detect the density of the recording on the recording medium, and the erasing light source. 3. Use as a preliminary erasing means.
An optical decoloring device according to item 1. 6. The optical decoloring device according to claim 1, further comprising a blowing unit (38, 40) for blowing air to the erasing light source for applying warm air to the recording medium. apparatus. 7. A power supply means (64) for supplying power to said erasing light source (28, 30), said power being supplied when said recording means detects that recording on a recording medium is light. Supplying power to the erasing light source by the supplying means, and stopping the supply of power to the erasing light source by the power supplying means when the detection means detects that the recording on the recording medium is dark. The optical decoloring device according to claim 1, which is characterized in that. 8. The optical erasing device according to claim 7, wherein the power is stopped at least until the recording medium is discharged. 9. The conveying means includes a step motor (70), and further has a counter for counting the number of steps from when the recording medium is sucked to when the recording medium is conveyed to the position of the erasing light source. The power supply is stopped only when the recording medium passes the position of the erasing light source when the recording medium detects that the recording medium is dark. 7. The optical decoloring device according to 7. 10. The conveying means is a step motor (70).
And a counter (66) for counting the number of steps from when the recording medium (S) is sucked to when it is conveyed to the position of the detecting means, and when the recording medium is at the position of the detecting means. The optical erasing device according to claim 1, wherein the detecting means is operated only in the case. 11. A means (66a) for generating an enable signal for validating the output of the detecting means when a recording medium is at the position of the detecting means, and a logic for receiving the output of the detecting means and the enable signal. Optical erasing device according to claim 10, characterized in that it is provided with a circuit (80). 12. The dark portion (B) of the recording medium (S) when the dark portion (B) of the recording medium is detected by the detecting means, the light source (28, 30) for erasing. 2. The optical apparatus according to claim 1, wherein the erasing light source is turned off when passing through the sheet, and the erasing light source is turned on when other portions of the recording medium pass through the erasing light source. Erasing device. 13. The conveying means includes a variable speed motor, and the detecting means provides a dark portion (B) of the recording medium (S).
13. When is detected, the variable speed motor is moved at a high speed to convey the recording medium when a dark recording portion of the recording medium passes through the erasing light source.
An optical decoloring device according to item 1. 14. Conveying means (18, 20, 22, 70) for conveying the recording medium (S) along the conveying path (P),
Decoloring light source (28, 30) provided in the middle of the transportation path
And an auxiliary erasing light source (54) provided on at least one of the upstream and downstream sides of the erasing light source in the middle of the conveying path.