JP2010266698A - Image forming apparatus with erasing function - Google Patents

Abstract

An image forming apparatus with a erasing function having a function of erasing an image and a function of determining whether a erased state of a decolored image is acceptable.
A paper feed cassette 33 accommodates paper that has been imaged with decolorable toner (R) and has been used as a document. The erasing device 40 disposed between the standby roller pair 37 for feeding the sheet and the secondary transfer portion where the secondary transfer roller 19 is disposed has a built-in heat source disposed opposite to the conveyance path a. The preliminary heating roller 41 preheats while conveying the paper, and the downstream erasing LED head 42 erases the image of the paper by erasing the erasing light of the erasing wavelength, and the downstream erasing detection sensor 43 The reflected light of the decoloring irradiation light is detected. If the erasing state based on the detection result is acceptable, a new image is transferred to the sheet at the secondary transfer unit, fixed by the fixing unit 4, and discharged to the discharge tray 45. If the erasable state is negative, the sheet passes through the secondary transfer portion and the fixing unit 4 and is discharged out of the apparatus from the disposal port 49.
[Selection] Figure 1

Description

  The present invention provides a function of erasing an image formed by a simple mechanism in addition to a function of forming an image by an electrophotographic method, and a function of determining pass / fail of a erased state of the erased image. The present invention relates to an image forming apparatus.

  As part of protecting the global environment, paper resources have been saved recently. In the saving and reuse of paper resources such as image forming apparatuses, effective use of the back side of paper for single-sided printing has already been made in general society. In general, the used paper is collected and used as a raw material of the paper and reused as recycled paper.

  However, when reusing paper for single-sided printing, the number of reuse is usually limited to one. In addition, when the material is reused as a raw material, energy and cost are required for the recovery itself, and energy is also applied when processing the raw material.

  Therefore, various efforts have been made to make it possible to use the paper multiple times in the office. In order to reuse paper once formed with toner images as paper resources, the image on the paper formed with toner may be physically removed or decolored with light to make the paper reusable. It is considered.

  In order to physically remove the image and reuse the paper, a processing solution for removing the toner is applied to the image forming surface of the paper and heated to dissolve the toner to remove the image. There are methods such as polishing the image forming surface and scraping off the toner image. However, these methods are troublesome because they are troublesome and the paper to be reused is easily damaged.

  As a decoloring method using light, when forming an image on a sheet for the first time, a method of recording an image on a sheet with a light decoloring toner in advance and erasing the image by light irradiation with a special light source is mainly used. It has become a thing.

  For example, the toner image can be erased by such light irradiation. For example, in a dedicated color erasing apparatus, the density of the image is detected in advance, the light printed image is erased, and the dark color image is erased. There has been proposed an apparatus that discharges the image as it is without using the apparatus and performs erasing at high speed (see, for example, Patent Document 1).

  However, when such a dedicated erasing device is used, the erasing device is installed in the office in addition to the printing device such as a printer, so that power is also required separately from the printer. The installation floor area is required separately from the printer. Therefore, there is a problem that it is not always convenient for the user.

  Therefore, in order to solve such a problem, an apparatus has been proposed in which an image forming apparatus uses a fixing device for image formation and an erasing device for erasing in common. This device is based on a commonly used technique for erasing a toner image, in which the toner image is heated in advance and then the erasing light is effectively applied when the erasing light is irradiated (for example, Patent Documents). 2).

  By the way, when the printing device and the erasing device are integrated and printing is performed in a series of flows immediately after erasing, it is important to determine whether erasing has been completed in order to maintain the quality of the printed image. Become.

  Therefore, an image erasing device is incorporated into the electrophotographic copying machine, and after erasing, it is judged whether the erasure is complete by another light source and a sensor. If it is judged that the image is not completely erased, the image is erased. An electrophotographic copying machine with a repeating erasing device has been proposed (see, for example, Patent Document 3).

Japanese Patent Laid-Open No. 08-305228 JP 07-096434 A JP 05-289575 A

  Incidentally, in the prior art of Patent Document 3, it is natural to provide a light source for erasing separately from a light source such as an optical recording head of an image forming apparatus. It is determined whether or not the erasure is complete.

  Even if a light source for erasing different from that of a normal image forming apparatus is provided, a member having a mechanism different from that of the image forming apparatus is required, and another light source is provided for determining whether or not erasing is complete. In addition to the need for a member having a mechanism different from that of the normal image forming apparatus, a conveyance mechanism different from that of the normal image forming apparatus is also required, which not only increases the cost of the member but also makes the control complicated. This has the problem that it takes time.

  In order to solve the above problems, an image forming apparatus with a color erasing function of the present invention is an image forming apparatus with a color erasing function having a function of performing image formation by an electrophotographic method and a function of erasing a formed image. A decolorable toner image decoloring part for decoloring an image of the decolorable toner formed on the recording medium by a heating unit and a decoloring light source, and disposed in the vicinity of the decolorable toner image decoloring part, A decolored reflected light detection unit that detects reflected light of the decolored light irradiated on the image, and the image erased by the decolored light based on the intensity of the reflected light detected by the decolored reflected light detection unit. And a decoloring state pass / fail judgment unit for judging pass / fail of the color state.

  In the image forming apparatus with a color erasing function, for example, the color erasable toner image color erasing unit includes a heating roller extending as a heating unit corresponding to a main scanning direction of the recording medium, and a color erasing light source. And a line-type light irradiation device composed of an LED (light emitting diode) array that emits near-infrared rays. In addition, for example, the decolored reflected light detection unit is configured by a line-type light receiving sensor including a light receiving LED array extending corresponding to the main scanning direction of the recording medium.

  According to the present invention, in addition to a function of performing image formation by an electrophotographic method, a color erasing function having a function of erasing an image formed by a simple mechanism and a function of determining whether or not the color erased state of the erased image is acceptable There is an effect that an image forming apparatus with a function can be provided.

1 is a side sectional view schematically showing an internal configuration of an image forming apparatus with a color erasing function according to Embodiment 1 of the present invention. 1 is a circuit block diagram including a control device of an image forming apparatus with a color erasing function according to Embodiment 1 of the present invention. (a) is a perspective view schematically showing in more detail the configuration other than the preheating roller inside the erasing apparatus of the image forming apparatus with the erasing function according to Embodiment 1 of the present invention, and (b) is a side view thereof. FIG. FIG. 6 is a flowchart showing a processing operation for detecting and removing a sheet in which the decolored state is incomplete or incapable of decoloring, completing the decoloring of the decolorable sheet, and performing new printing on the decolored paper surface. is there. (a), (b) is a figure which shows the example which attached the SELFOC lens to the LED head for erasing which irradiates erasing light. It is a figure which shows typically the internal structure of the decoloring apparatus corresponding to the double-sided printing of the image forming apparatus with a decoloring function which concerns on Example 2 of this invention.

  Hereinafter, embodiments of the present invention will be described in detail.

  FIG. 1 is a side sectional view schematically showing an internal configuration of the image forming apparatus with a color erasing function according to the first embodiment. The image forming apparatus 1 with an erasing function is an electrophotographic secondary transfer type two-tandem image forming apparatus, and includes an image forming unit 2, an intermediate transfer belt unit 3, a fixing unit 4, a paper feeding unit 5, And a duplex printing conveyance unit 6.

  The image forming unit 2 has a configuration in which two image forming units 7 (7R, 7K) are arranged in parallel. The image forming unit 7R contains a decolorizable toner. The image forming unit 7K contains a very general monochrome toner such as carbon black for forming a normal monochrome image.

  In this example, the decolorizable toner is, for example, a toner formed by uniformly dispersing an organic boron compound and a near-infrared absorbing dye in a styrene resin, and decoloring is performed by absorbing near-infrared rays. Toner. An example of the production method will be described later.

  The two image forming units 7 have the same configuration except for the type of toner stored in the toner container (toner cartridge). Therefore, the configuration of the image forming unit 7R for the decolorizable toner (R) will be described below as an example.

  The image forming unit 7 includes a photosensitive drum 8 at the bottom. The photosensitive drum 8 has a peripheral surface made of, for example, an organic photoconductive material. A cleaner 9, a charging roller 11, an optical writing head 12, and a developing roller 14 of the developing device 13 are arranged around the periphery of the photosensitive drum 8.

  The developing unit 13 accommodates either the decolorizable toner (R) or the black toner (K) in the upper toner container as shown by R and K in the figure, and the lower part is connected to the lower part. A toner replenishing mechanism is provided.

  Further, the developing roller 14 is provided in the lower side of the developing unit 13 at the side opening, and a toner stirring member, a toner supply roller for supplying toner to the developing roller 14, and a toner layer on the developing roller 14 are fixed layers. It has a doctor blade that regulates the thickness.

  The intermediate transfer belt unit 3 has an endless transfer belt 15 extending in a flat loop shape from substantially the left and right sides of the figure at the center of the main body, and the transfer belt 15 is stretched over the transfer belt 15. A driving roller 16 and a driven roller 17 are provided to circulate and move the belt 15 counterclockwise in the figure.

  A primary transfer roller 18 made of a conductive foam sponge that presses against the lower peripheral surface of the photosensitive drum 8 via the transfer belt 15 is disposed in the loop of the flat loop-shaped transfer belt 15.

  The transfer belt 15 transfers the toner image on the photosensitive drum 8 directly to the belt surface by the primary transfer roller 18 (primary transfer), and further transfers the toner image onto the paper (secondary transfer). Transport to the next transfer position.

  At this secondary transfer position, the secondary transfer roller 19 is pressed against the driven roller 17 via the transfer belt 15 to form a secondary transfer portion. A pair of conveyance rollers 20 is arranged on the upstream side (downward in the drawing) of the secondary transfer unit in the sheet conveyance direction.

  The intermediate transfer belt unit 3 includes a belt position control mechanism (not shown) in which the primary transfer roller 18 is disposed in the loop of the flat loop-shaped transfer belt 15. The belt position control mechanism allows the two image forming units 7R and 7K of the decolorable toner (R) and the black toner (K) to be separately separated from the primary transfer roller 18 and the transfer belt 15. it can.

  That is, the belt position control mechanism moves the transfer belt 15 of the intermediate transfer belt unit 3 in the monochrome mode (only the primary transfer roller 18 corresponding to the image forming unit 7K is in contact with the transfer belt 15), and the decoloring printing mode (image forming). Only the primary transfer roller 18 corresponding to the unit 7 </ b> R is in contact with the transfer belt 15) and all non-transfer modes (two primary transfer rollers 18 are separated from the transfer belt 15).

  Further, in the intermediate transfer belt unit 3, a belt cleaner unit 21 is disposed further upstream of the uppermost image forming unit 7 </ b> K in the belt moving direction on the upper surface portion so as to be almost along the entire lower surface portion. A flat and thin waste toner collecting container 22 is detachably disposed.

  The belt cleaner unit 21 removes waste toner remaining on the transfer belt 15 to clean the transfer belt 15 and sends the removed waste toner to a waste toner collection container 22 through a transport pipe (not shown).

  A fixing unit 4 is disposed downstream (upward in the drawing) in the sheet conveyance direction from the secondary transfer unit. The fixing unit 4 includes a heating roller 26, a fixing belt 27, a fixing roller 28, a heating roller 26, an inside surrounded by a heat-insulating housing 25 having a paper inlet 23 at the bottom and a paper outlet 24 at the top. A halogen heater 31 is mounted inside the heating roller 26 as a heat source.

  The endless fixing belt 27 is provided to transmit the heat of the heating roller 26 to the surface of the fixing roller 28. The pressure roller 29 has an outer peripheral portion made of a heat resistant material made of silicon rubber or the like.

  The pressure roller 29 is also provided with a halogen heater 32 therein and is in pressure contact with the fixing roller 28 via the fixing belt 27. A fixing portion is formed by the pressure contact portion.

  Next, the paper feed unit 5 includes a paper feed cassette 33 that is detachably attached to the lower part of the main unit. Although not shown in the figure, the paper feed cassette 33 accommodates a large number of sheets as recording media on which images are formed. A paper take-out roller 34, a feed roller 35, a separating roller 36, and a standby conveyance roller pair 37 are disposed in the vicinity of the paper feed port (right side of the drawing) of the paper feed cassette 33.

  Further, above the paper feed cassette 33, an electrical unit 38 with an appropriate circuit board is disposed at a position along the lower surface of the waste toner collection container 22. The circuit board is equipped with a control device, which will be described in detail later, consisting of a plurality of electronic components.

  Further, a decoloring device 40 unique to this example is disposed between the standby conveyance roller pair 37 and the conveyance roller pair 20 in the paper conveyance direction (vertical upward direction in the drawing) of the standby conveyance roller pair 37. . The decoloring device 40 includes a preheating roller 41, a decoloring LED head 42, and a decoloring detection sensor 43.

  The erasing device 40 has already been formed on the first surface (the surface on which an image is first formed) of the sheet fed from the standby conveying roller pair 37 along the conveying path a to the conveying roller pair 20. The toner image softened (or melted) by applying heat to the chromatic toner image, and the softened (or melted) toner image is irradiated with near infrared rays as will be described in detail later. Is erased, and whether or not the erased state is possible is determined.

  On the downstream side (upward in the drawing) of the erasing device 40 is the secondary transfer portion described above, and on the further downstream side, the fixing unit 4 is also disposed, further downstream of the fixing unit 4. On the side, an unloading roller pair 44 for unloading the fixed sheet from the fixing unit 4 is disposed.

  Disposed on the downstream side of the carry-out roller pair 44 is a paper discharge roller pair 46 that discharges the paper carried out from the carry-out roller pair 44 to a paper discharge tray 45 formed on the upper surface of the apparatus. On the upstream side of the paper discharge roller pair 46, a rotating flap 47 is provided which always has a free end along a roller above the paper discharge roller pair 46.

  The rotation flap 47 rotates to the solid line position and the broken line position in the figure with the hinge 48 as a fulcrum. The rotating flap 47, on the one hand, rotates to the position indicated by the solid line in the figure for a sheet on which an image has been normally formed, and discharges the sheet to the sheet discharge tray 45 by the pair of carry-out rollers 44. For a paper on which an image could not be formed, the paper is rotated to a broken line position in order to discharge the paper from the disposal port 49 to the outside of the apparatus.

  Next, the duplex printing conveyance unit 6 includes a start return path 51a that branches from the intermediate conveyance path between the carry-out roller pair 44 and the discharge roller pair 46 to the right in the figure, and then an intermediate return path that curves downward. 51b and a terminal return path 51c that bends in the left lateral direction opposite to the above and finally reverses the return sheet. The exit of the end return path 51 c communicates with a conveyance path to the standby conveyance roller pair 37 corresponding to the sheet feeding cassette 33 of the sheet feeding unit 5.

  In addition, the duplex printing transport unit 6 includes four pairs of return rollers 52 (52a, 52b, 52c, 52d) disposed in the middle of the return paths 51 (51a, 51b, 51c). . The sheet is nipped and conveyed by the pair of return rollers 52, guided by the return path 51, and returned from the downstream side to the upstream side.

  FIG. 2 is a circuit block diagram including the control device of the image forming apparatus 1 with the erasing function. As shown in FIG. 2, the circuit block is centered around a central processing unit (CPU) 53, and an interface controller (I / F_CONT) 54 and a printer controller (PR_CONT) 55 are connected to the CPU 53 via a data bus. ing. A printer printing unit 56 is connected to the PR_CONT 55.

  Connected to the CPU 53 are a ROM (read only memory) 57, an EEPROM (electrically erasable programmable ROM) 58, an operation panel 59 of the main body operation unit, and a sensor unit 61 to which outputs from sensors arranged in the respective units are input. Has been. A system program is stored in the ROM 57, and the CPU 53 performs processing by controlling each unit in accordance with the system program.

  That is, in each unit, first, the I / F_CONT 54 converts print data supplied from a host device such as a personal computer into bitmap data and develops it in the frame memory 62. In the frame memory 62, a storage area is set for each of the black toner (K) and the decolorizable toner (R), and data of each color is developed in the corresponding area.

  The data developed in the frame memory 62 is output to the PR_CONT 55 and is output from the PR_CONT 55 to the printer printing unit 56.

  The printer printing unit 56 is an engine unit, and under the control of the PR_CONT 55, the rotation drive system including the photosensitive drum 8, the primary transfer roller 18 and the like shown in FIG. 1, the charging roller 11, the optical writing head 12, etc. A drive output to a process load such as an applied voltage of an image forming unit having a driven portion is controlled.

  Further, the printer printing unit 56 includes a belt driving unit 63 that controls the vertical movement of the belt position control mechanism of the intermediate transfer belt unit 3, a fixing driving unit 64 that controls each part of the fixing unit 4, and the erasing device 40. The drive output to the decoloring drive unit 65 that controls each unit is controlled.

  The image data of the black toner (K) and decolorable toner (R) output from the PR_CONT 55 is supplied from the printer printing unit 56 to the corresponding optical writing head 12 shown in FIG. .

  Here, the erasing apparatus 40 of this example will be further described. First, the decolorizable toner (R) used in this example is manufactured such that its glass transition point is 50.3 ° C. and its softening point is 106 ° C.

  The preheating roller 41 of the erasing apparatus 40 shown in FIG. The wavelength distribution of the halogen lamp is wide and includes a wide wavelength distribution of near infrared rays, so that it is suitable as a heat source for heat radiation.

  In this example, the temperature of the heat radiation of the halogen lamp can be varied, and the heating temperature for the paper surface to be decolored can be set in the range of 50 ° C to 100 ° C. This temperature range is a range in which the heating temperature for decolorization can be set to a range that is higher than the glass transition point of the decolorable toner and lower than the softening point.

  Further, the decoloring LED head 42 in this example is formed of an LED array. Since LEDs have a very narrow wavelength distribution, there is very little generation of light with a wavelength unnecessary for decoloring depending on the selection of the LED, that is, light with a wavelength distribution with good decoloring efficiency is emitted. LED to be selected can be selected.

  Since the near-infrared photosensitive dye having a sensitivity of 817 nm is used for the decolorable toner of this example, in order to cope with this decoloration, the LED light of the decoloring LED head 42 is generally a dye. Those having a center wavelength close to 820 nm, which is the absorption wavelength, are superior. However, as an actual decoloring characteristic, if the full width at half maximum is taken into consideration even if the center wavelength is 850 nm, sufficient emission intensity can be obtained. There is no problem as a decoloring characteristic.

  That is, if an LED light having a wavelength distribution with a half-value width of 50 nm or less is selected, it can be seen that a light having a center wavelength of 810 nm to 850 nm is suitable for decoloring. In particular, an LED lamp with a center wavelength of 850 nm is one of the most popular LED lamps in the near-infrared region, and is superior in device design from the viewpoint of energy efficiency and cost.

  Further, in this example, as shown in FIG. 1, a decoloring detection sensor 43 that detects light used for decoloring as reflected light in the vicinity of the decoloring LED head 42 as a decoloring light source is provided. It is attached. A reflection type light receiving element having sensitivity to near infrared rays is suitable for the decoloring detection sensor 43, but an image sensor such as a CCD (Charge Coupled Device) usable in the near infrared region may be used.

  FIG. 3A is a perspective view schematically showing an example of the state of near-infrared irradiation in the decoloring LED head 42 and detection of reflected light by the decoloring detection sensor 43, and FIG. It is a side view.

  As shown in FIG. 3 (a), the decoloring LED head 42 is configured by arranging LED array chips 67 having a center wavelength of 830 to 850 nm having a wavelength distribution with a half-value width of 50 nm or less arranged in the longitudinal direction of the head. Yes. The distance between the paper 66 and the LED array chip 67 is about 20 mm.

  Thus, since the distance between the paper 66 and the LED array chip 67 is about 20 mm, which is a relatively long distance, the decolorizing irradiation light 68 from the decoloring LED head 42 extends radially, and an irradiation range 69 on the paper 66. Is spreading. While the paper 66 is being conveyed in the direction indicated by the arrow a (passing through the decoloring device 40), the image forming surface of the paper 66 has a decoloring irradiation light 68 on the image forming surface without any interruption corresponding to the wide irradiation range 69. Is irradiated.

  In combination with the preheating by the preheating roller 41, the decoloring irradiation light 68 is emitted in a wide irradiation range 69, so that the decoloring can be sufficiently performed even if the paper 66 is conveyed at a high speed. However, if the density of the image is very high, the decolored state may be incomplete.

  Further, when the operator stacks the paper 66 printed with the color erasing toner (R) on the paper feed cassette 33 for color erasing, the operator mistakenly processes the normal toner that is not the color erasing toner (R). Even if the paper printed with is mixed, the erasing state is impossible.

  In the case of this example, as shown in FIG. 3 (b), the decoloring detection sensor 43 detects reflected light in the vicinity of the end of the irradiation range 69 of the irradiation light 68 in the paper conveyance direction. As a result, the reflected light of the erasing irradiation light 68 in the portion where the erasing should be sufficiently advanced is detected, so that the paper where the erasing state is incomplete or the erasing state is impossible is removed. It can be detected without error by separating it from erasable paper.

  FIG. 4 shows a process of detecting and eliminating a paper whose erasing state is incomplete or incapable of erasing, completing erasing of the erasable paper, and performing new printing on the paper after erasing. It is a flowchart which shows operation | movement. In this process, new printing is performed at a processing speed synchronized with the decoloring process.

  In FIG. 4, when processing is started by an input instruction or the like from the operation panel 59 by the operator, first, paper feed processing is performed (step S1).

  In this process, the paper taken out by the paper take-out roller 34 from the paper feed cassette 33 containing the paper 66 printed with the erasable toner, used as a document, and which can be erased. 66 is fed to the standby conveying roller pair 37 by the feeding roller 35 and the separating roller 36.

Subsequently, a decoloring process is performed (step S2).
In this processing, the sheet 66 whose skew has been corrected by the apparatus standby conveyance roller pair 37 is immediately sent to the erasing apparatus 40. In the erasing device 40, the paper 66 is heated so that the toner image on the paper 66 has a temperature equal to or higher than the glass transition point while the carried paper 66 is nipped and conveyed by the preheating roller 41.

  Then, the decoloring process shown in FIGS. 3A and 3B is executed. The decoloring detection sensor 43 detects the reflected light of the decoloring irradiation light 68 during execution of the decoloring process, and notifies the CPU 53 of the detection result. It should be noted that the detection of the reflected light of the decoloring irradiation light 68 may be performed at one place or a plurality of places where the image of the paper 66 is present. Further, in this example, after passing through the erasing device 40, a mechanism for detecting the erasing state again in the downstream portion is not provided.

Subsequently, the decoloring state is determined (step S3).
In this processing, the EEPROM 58 of the control device stores in advance a threshold value corresponding to the luminance data of the reflected light that can be erased by determining the erased state. The CPU 53 reads the threshold value from the EEPROM 58 and compares it with the luminance data indicated by the detection result of the decoloring irradiation light 68 from the decoloring detection sensor 43.

  Then, the CPU 53 determines that the decoloring state is good if the luminance data of the reflected light of the decoloring irradiation light 68 detected by the decoloring detection sensor 43 indicates a luminance equal to or higher than the compared threshold (S3 is OK). . On the other hand, if the luminance data of the reflected light indicates a luminance lower than the compared threshold value, the decolored state is not possible (S3 is NG).

When it is determined that the erasing state is good (S3 is OK), the erasing process is continued (step S4).
As a result, the erasing process shown in FIGS. 3A and 3B is performed on the entire surface of the sheet 66, and the sheet 66 that has been decolored to become a blank sheet is taken over by the conveying roller pair 20 and is transferred to the second position. The next transfer roller 19 is conveyed via the transfer belt 15 to a secondary transfer portion that is in pressure contact with the driven roller 17.

  On the transfer belt 15, a toner image with a normal monochrome toner developed by the image forming unit 2 or a decolorizable toner image with a decolorable toner is primarily transferred, and this toner image is transferred to the secondary transfer unit. And is secondarily transferred to the sheet 66 that is in a blank state. The paper 66 onto which the toner image has been secondarily transferred is carried into the fixing unit 4 and the toner image is fixed on the paper surface.

Subsequently, a discharge process is performed (step S6).
In this process, the paper 66 that has become a blank paper state due to erasing and has a new toner image fixed thereon and becomes a useful document is guided by a rotating flap 47 that rotates downward, and the paper discharge roller pair 46. Then, the sheet is taken over and discharged to the discharge tray 45 by the discharge roller pair 46.

  On the other hand, if it is determined in step S3 that the decolored state is not possible (S3 is NG), the above-described printing process is stopped (step S7), and the paper 66 is discharged (step S8).

  In the discharge process in this case, the paper 66 simply passes through the secondary transfer portion and the fixing unit 4, and is taken over by the carry-out roller pair 44 of the fixing unit 4 and is rotated upward. It is guided to 47 and is discharged out of the apparatus through the disposal port 49.

  FIGS. 5A and 5B are diagrams showing an example in which a Selfoc lens 71 is attached to a decoloring LED head 42 that emits decoloring light. FIG. 5A shows a state in which the LED array chips 67 of the erasing LED head 42 are mounted at a high density with a narrower interval.

  A self-focus lens 71 is attached to the LED head 42 for erasing, and when a light spot emitted from the LED chip is set with a high-definition spot by the self-focus lens, an image is selectively and highly precisely erased. Is also possible. Also in this case, as the decoloring detection mechanism, as shown in FIG. 5 (b), there is no problem if the decoloring detection sensor 43 is arranged on the opposite side by tilting the optical axis projected from the Selfoc lens 71. There is no.

According to the mechanism constituting the erasing apparatus shown in FIGS. 1, 3 (a), 3 (b) and FIGS. 5 (a), 5 (b), it is possible to cope with double-sided printing with erasable toner. .
FIG. 6 is a diagram schematically illustrating an internal configuration of a decoloring apparatus corresponding to double-sided printing in the image forming apparatus 1 with a decoloring function according to the second embodiment.

  As shown in FIG. 6, in the image forming apparatus 1 with a color erasing function according to the second embodiment, above the preheating roller 41 disposed opposite to the color erasing apparatus 40, respectively, on both sides of the conveyance path a. A decoloring LED head 42 and a decoloring detection sensor 43 are arranged.

  As described above, in the case of double-sided printing paper, the erasing mechanism inside the erasing apparatus is also installed on both sides, and can be easily configured to monitor the erasing state simultaneously on both sides.

Here, a method for producing the decolorizable toner (R) will be described.
Infrared photosensitive dye “IRT” (Showa Denko) having a sensitivity of 817 nm, 1.5 parts by mass of organic boron compound decoloring agent “P3B” (Showa Denko), polyester binder resin for toner (Kao) 90.5 parts by weight, 1.5 parts by weight of negative charge regulator “LR-147” (manufactured by Nippon Carlit), 2.5 parts by weight Henschel mixer of Carnauba WAX1 powder (imported by Kato Yoko Co., Ltd.) (Mitsui Mine) and mix.

  Subsequently, the above mixture is melt kneaded with a twin-screw kneader. The kneaded material thus obtained is roughly crushed with a rotoplex (manufactured by Hosokawa Micron) to obtain a coarsely crushed material. The resulting coarsely crushed material is pulverized by an impact pulverizer so that the average particle size becomes 9 μm.

  One part by mass of silica “R972” (manufactured by Nippon Aerosil Co., Ltd.) as an external additive is added to 100 parts by mass of the pulverized product obtained by this pulverization, and mixed with a Henschel mixer to obtain a decolorizable toner.

  As described above, the toner image developed with this decolorable toner, transferred to a sheet, and fixed has a decolorization sensitivity in the near infrared of 817 nm. In this example, an LED light having a center wavelength of 830 nm or 850 nm is used for erasing the decolorizable toner image.

  Irradiation light having a wavelength close to 820 nm is superior to decoloring a decolorizable toner image having decolorization sensitivity in the near infrared of 817 nm. However, as an actual decoloring characteristic, irradiation at 850 nm If sufficient intensity is obtained even with light, there is no problem as a decoloring characteristic.

  According to an embodiment of the present invention, in an image forming apparatus with a color erasing function in which a color erasing apparatus and a printing mechanism are integrated, a light source as a color erasing energy and a light source supplied to a photodetector for monitoring the color erasing state are provided. Since they are the same, it is possible to reliably determine whether or not the erasing state is possible at the same timing as the erasing operation, so that if the erasing state is determined to be defective, it is possible to promptly perform the printing after erasing. Thus, it is possible to provide an image forming apparatus with an efficient color erasing function without consuming toner on unnecessary paper.

  Further, since the decolored state is detected simultaneously with the decoloring, it is convenient because the decolored state can be easily grasped without using a specific marking.

  Further, since the same light source is used as the erasing light source and the erasing state detection light source, there is an effect that the erasing timing and the erasing discrimination are synchronized, and the accuracy of the erasing discrimination is improved.

  Similarly, since the same light source is used for the erasing light source and the erasing state detection light source, the design of each process for detecting the erasing state and the erasing state is made common, thereby facilitating the design and the device. It is economical because downsizing is maintained.

  INDUSTRIAL APPLICABILITY The present invention is used for an image forming apparatus with a erasing function having a function of performing image formation by an electrophotographic method, a function of erasing a formed image, and a function of determining pass / fail of a decolored state of a erased image. be able to.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus with a decoloring function 2 Image forming part 3 Intermediate transfer belt unit 4 Fixing unit 5 Paper feed part 6 Duplex printing conveyance unit 7 (7R, 7K) Image forming unit 8 Photosensitive drum 9 Cleaner 11 Charging roller 12 Light Writing head 13 Developing device 14 Developing roller 15 Transfer belt 16 Driving roller 17 Driven roller 18 Primary transfer roller 19 Secondary transfer roller 20 Conveying roller pair 21 Belt cleaner unit 22 Waste toner collection container 23 Paper carry-in port 24 Paper discharge port 25 Thermal insulation Housing 26 Heating roller 27 Fixing belt 28 Fixing roller 29 Pressure roller 31, 32 Halogen heater 33 Paper feed cassette 34 Paper take-out roller 35 Feeding roller 36 Rolling roller 37 Standby conveying roller pair 38 Electrical component 40 Decoloring device 41 Preheating roller 42 LE for color erasing Head 43 Decoloration detection sensor 44 Unloading roller pair 45 Discharging tray 46 Discharging roller pair 47 Rotating flap 48 Hinge 49 Disposal port 51 Return path 51a Start return path 51b Intermediate return path 51c End return path 52 (52a, 52b, 52c 52d) Return roller pair 53 CPU (central processing unit)
54 Interface Controller (I / F_CONT)
55 Printer Controller (PR_CONT)
56 Printer printing section 57 ROM (read only memory)
58 EEPROM (electrically erasable programmable ROM)
59 Operation Panel 61 Sensor Unit 62 Frame Memory 63 Belt Drive Unit 64 Fixing Drive Unit 65 Decoloring Drive Unit 66 Recording Medium (Paper)
67 LED array chip 68 Decolorizing irradiation light 69 Irradiation range 71 Selfoc lens

Claims (3)

In an image forming apparatus with a erasing function having a function of forming an image by an electrophotographic method and a function of erasing a formed image,
A decolorable toner image decoloring unit that decolorizes an image of the decolorable toner formed on the recording medium with a heating unit and a decoloring light source;
A decolored reflected light detection unit disposed in the vicinity of the decolorable toner image decoloring unit and detecting reflected light of the decolored light irradiated on the image;
A decoloring state pass / fail determination unit that determines whether the decoloring state of the image by the decoloring light is acceptable based on the intensity of the reflected light detected by the decolored reflected light detection unit,
An image forming apparatus with a color erasing function. The decolorizable toner image decoloring section includes a heating roller extending as the heating section corresponding to the main scanning direction of the recording medium, and an LED (light emitting diode) array that emits near infrared light as the decoloring light source. A line-type light irradiation device comprising:
The image forming apparatus with a decoloring function according to claim 1. The decolored reflected light detection unit is a line type light receiving sensor comprising a light receiving LED array extending corresponding to the main scanning direction of the recording medium.
The image forming apparatus with a decoloring function according to claim 1.