JP2011227135A - Multifunctional image forming apparatus with toner decoloring function - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multifunctional image forming apparatus with a toner decoloring function, the apparatus capable of printing and decoloring a decolorable toner image, and capable of immediately performing the other of the decoloring and reading original modes, which is urgently required, without changing the operation mode.SOLUTION: The image forming part 2 of an MFP 1 can form a full color image and a monochrome image on a paper using an image forming unit 4, and a decolorable toner image on the paper using an image forming unit 8R replacing an image forming unit 8K. In an image scanner part 3, a document placed on the paper feed tray 49a or 49b of an ADF unit 39 or on a flatbed part 38 is irradiated with white light generated by turning on all of the three-primary color LED chips 79 of a reading/decoloring part 44 and read by a CCD chip 74. While a paper with a decolorable toner image placed on the paper feed tray 49b or 49a is being conveyed by a revolving conveying roller 55, the paper is pre-heated by a ceramic heater 57, and only the red 79r LED chip, which is approximated to near infrared light, of the three-primary color LED chips 79 is driven to emit light by applying strong electric power to decolor the decolorable toner image. The paper feed tray 49a and 49b are mutually exclusively driven.

Description

  The present invention relates to a multifunctional image forming apparatus with a toner erasing function capable of forming an image of a erasable toner on a printing medium and erasing an image on the printing medium formed of the erasable toner.

  Conventionally, a decolorable toner using a near-infrared photosensitive dye is used, and light is emitted from a decoloring light source to reuse the paper on which an image is formed with the decolorable toner. A decoloring apparatus that performs decoloring is known (for example, see Patent Documents 1 and 2).

  There is also known an erasing and image forming apparatus in which a erasing light source is incorporated in a conventional printer, not as a dedicated erasing apparatus (see, for example, Patent Documents 3, 4, 5, and 6).

  At the time of erasing, the printed matter is heated by heat from a heater incorporated in the apparatus, and the printed matter is irradiated with light from a light source for erasing. In such an apparatus, a heater and a light source are installed in the paper path. When a paper already printed with the decoloring toner passes through the path, the paper is heated by the heater to emit light. It has a mechanism to irradiate.

  On the other hand, in recent years, there is an apparatus called MFP (Multi Function Peripheral or Multi Function Printer) that also functions as a printer, a scanner, a copier, and a FAX (for example, Patent Literature) 7, 8).

  Further, as a technique related to the present invention, a technique using a ceramic heater for the purpose of improving thermal efficiency with respect to a fixing device of an image forming apparatus is disclosed (for example, see Patent Document 9).

JP 2000-081816 A Japanese Patent Laid-Open No. 07-175379 JP 05-289575 A JP 05-289576 A JP 07-096434 A Japanese Patent Application Laid-Open No. 07-199753 JP 2000-057842 A JP 2008-067213 A

  However, when the printed matter is heated at a high temperature of 130 ° C. to 420 ° C. as in the prior art of Patent Document 1, a temperature rise in the apparatus main body and a large power consumption are required. The problem is a major problem in printer design. However, this problem has a problem that Patent Document 1 is left unsolved without any description.

  Each of the preceding examples basically uses a halogen lamp as a light source for erasing. In general, it is well known that halogen lamps have a wide range of wavelength distribution. Therefore, the halogen lamp also emits a wavelength unnecessary for decoloring. There is a problem that problems such as a rise in temperature in the apparatus main body due to generation of light having a wavelength unnecessary for decoloring and large power consumption remain unsolved.

  Further, the decoloring and image forming apparatus disclosed in Patent Documents 3, 4 and 6 is based on the premise of two light sources, ie, a light source for irradiating a document and a light source for decoloring, and there is a problem to be solved that the configuration is complicated. is there.

  Further, although the multifunctional image forming apparatus disclosed in Patent Document 7 or 8 has a multifunctional type, the multifunctional image forming apparatus does not have a function of forming an image with a decolorable toner on a print medium. There is a problem to be solved that there is no function for erasing the image on the print medium formed by the above, and that the multifunctional type is somewhat inferior in function.

  The present invention solves the above-described conventional problems, and can print a erasable toner image and can also erase the erasable toner image. It is an object of the present invention to provide a multifunctional image forming apparatus with a toner erasing function that can immediately perform the other task that requires urgentness without changing the mode.

  In order to solve the above problems, a multifunctional image forming apparatus with a toner erasing function according to the present invention includes a document conveying unit and a light irradiation that irradiates a predetermined light beam on an image surface of the document conveyed by the document conveying unit. And an image reading unit that reads an image of the original, and an image forming unit that forms an erasable toner image or a normal toner image on a sheet by an electrophotographic method. A multifunctional image forming apparatus with a toner erasing function having a toner erasing function for erasing the erasable toner image formed thereon via the image reading unit, the document conveying means And a plurality of paper feed trays for supplying the original or the paper.

  The present invention provides a multifunctional image forming apparatus with a toner erasing function capable of printing a erasable toner image and erasing the erasable toner image, and interrupts one of the erasing processing operation and the document reading operation. When the other task requiring urgency is performed, the other task requiring urgentness can be performed immediately without changing the mode of one task, and the task requiring urgentness can be performed efficiently and quickly. When the required work is completed, the suspended work can be resumed immediately.

1 is a cross-sectional view illustrating an internal configuration of a multifunctional image forming apparatus (MFP) with a toner erasing function according to Embodiment 1 of the present invention. 1 is a circuit block diagram including a control device of an MFP according to Embodiment 1. FIG. (a) is a figure explaining the structure and operation | movement of the reading and erasing part of MFP which concerns on Example 1, (b) is a figure which shows the lens structure of a LED light source and a reading part, (c) is a basic of LED light source It is sectional drawing which expands and shows a structure typically. 6 is a wavelength comparison diagram with a halogen lamp for explaining the light emission characteristics of a red LED chip having a center wavelength approximate to near-infrared light in the LED light source of the MFP according to Embodiment 1. FIG. 6 is a diagram for explaining light emission control of an LED light source employed in the MFP according to Embodiment 1. FIG. (a), (b) is a figure which shows the example of the shape of a ceramic heater employ | adopted in MFP which concerns on Example 1, and the example of a usage method.

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

  FIG. 1 is a cross-sectional view illustrating an internal configuration of a multifunctional image forming apparatus with a toner erasing function (hereinafter simply referred to as MFP) according to a first embodiment of the present invention. As illustrated in FIG. 1, the MFP 1 includes an image forming unit 2 and an image scanner unit 3.

First, the image forming unit 2 will be described.
The image forming unit 2 is an electrophotographic tandem type tandem color image forming apparatus, which is an image forming unit unit 4, an intermediate transfer belt unit 5, a paper feeding unit 6, a duplex printing transport unit 7, The unit 10 is configured.

  The image forming unit 4 has a configuration in which four image forming units 8 (8M, 8C, 8Y, 8K) are arranged in a multistage manner from right to left in FIG.

  Of the four image forming units 8, three image forming units 8M, 8C, and 8Y on the upstream side (right side in the figure) are magenta (M), cyan (C), and yellow (subtractive three primary colors), respectively. A monocolor image is formed with the color toner of Y).

  The most downstream image forming unit 8K can be replaced with the image forming unit 8R by opening the front door (not shown in FIG. 1 because of a sectional view). The image forming unit 8R is used solely and forms a decolorable toner image with the decolorable toner (R).

  Since the decolorizable toner is well known, the description of the method for producing the decolorable toner is omitted here.

  When used alone, the image forming unit 8K forms a black and white image, and when used together with the three image forming units 8M, 8C, and 8Y, the image forming unit 8K is mainly used for dark portions of characters and images. (K) A monochrome image is formed with toner.

  Each of the image forming units 8 has the same configuration except for the color of the toner stored in the toner container (toner cartridge). Therefore, the configuration of the image forming unit 8K for black (K) will be described below as an example.

  The image forming unit 8 includes a photosensitive drum 9 at the bottom. The photosensitive drum 9 has a peripheral surface made of, for example, an organic photoconductive material. A cleaner 11, a charging roller 12, an optical writing head 13, and a developing roller 15 of a developing device 14 are arranged around the periphery of the photosensitive drum 9.

  In the upper toner container, the developing unit 14 is magenta (M), cyan (C), yellow (Y), black (K) or decolored as indicated by M, C, Y, and K (R) in FIG. One of the toners (R) is accommodated, and a toner replenishing mechanism for the lower part is provided in the middle part.

  Further, the developing roller 15 is provided in the lower side of the developing unit 14 at the side opening, and a toner stirring member, a toner supply roller 16 for supplying toner to the developing roller 15, and a toner layer on the developing roller 15 are fixed. A doctor blade that regulates the layer thickness is provided.

  The intermediate transfer belt unit 5 has an endless transfer belt 17 that extends in a flat loop shape from substantially the left and right sides of the drawing at approximately the center of the main body device, and the transfer belt 17 is stretched over the transfer belt 17. A driving roller 18 and a driven roller 19 are provided to circulate and move the belt 17 counterclockwise in the figure.

  The transfer belt 17 directly transfers the toner image onto the belt surface (primary transfer) and conveys the toner image to the transfer position to the paper for further transfer (secondary transfer). The whole is called an intermediate transfer belt unit.

  The intermediate transfer belt unit 5 includes a belt position control mechanism 21 in the loop of the flat loop-shaped transfer belt 17. The belt position control mechanism 21 includes a primary transfer roller 22 made of a conductive foam sponge that presses against the lower peripheral surface of the photosensitive drum 9 via the transfer belt 17.

  The belt position control mechanism 21 includes three primary transfer rollers 22 corresponding to the three image forming units 8M, 8C, and 8Y of magenta (M), cyan (C), and yellow (Y) with a bowl-shaped support shaft. Rotate to the center with the same period.

  Then, the belt position control mechanism 21 sets one primary transfer roller 22 corresponding to the image forming unit 8K or 8R of black (K) or decolorizable toner (R) to the cycle of the three primary transfer rollers 22. The transfer belt 17 is moved away from and in contact with the photosensitive drum 9 by rotating at different rotation movement cycles.

  That is, the belt position control mechanism 21 determines the position of the transfer belt 17 of the intermediate transfer belt unit 5 in the full color mode (all four primary transfer rollers 22 are in contact with the transfer belt 17), monochrome mode, or decoloring toner mode. (Only the primary transfer roller 22 corresponding to the image forming unit 8K or 8R is in contact with the transfer belt 17) and all non-transfer modes (all four primary transfer rollers 22 are separated from the transfer belt 17).

  In the intermediate transfer belt unit 5, a belt cleaner unit is disposed further upstream of the uppermost image forming unit 8 </ b> M in the belt moving direction on the upper surface, and is flat and thin so as to be almost along the entire lower surface. The waste toner collecting container 23 is detachably disposed.

  The paper feed unit 6 includes two paper feed cassettes 24 arranged in two upper and lower stages, and in the vicinity of the paper feed opening (right side of the drawing) of the two paper feed cassettes 24, respectively, A feeding roller 26, a separating roller 27, and a standby conveying roller pair 28 are disposed.

  In the paper conveyance direction (vertical upward direction in the figure) of the standby conveyance roller pair 28, a secondary transfer roller 29 that is in pressure contact with the driven roller 19 via the transfer belt 17 is disposed, and a secondary transfer portion to the paper is arranged. Forming.

  A belt-type heat fixing device 31 is disposed on the downstream side (upper side in the drawing) of the secondary transfer unit, and on the further downstream side of the belt-type heat fixing device 31, the sheet after fixing is belt-type heat fixing device 31. A pair of carry-out rollers 32 for carrying out the paper and a pair of paper discharge rollers 34 for discharging the carried paper to a paper discharge tray 33 formed on the upper surface of the apparatus are disposed.

  The duplex printing transport unit 7 includes a start return path 35a branched from the transport path from the carry-out roller pair 32 to the paper discharge roller pair 34 in the right lateral direction in the figure, an intermediate return path 35b bent downward, and the above. A terminal return path 35c that bends in the opposite left lateral direction and finally reverses the return sheet is provided.

  Further, the duplex printing transport unit 7 includes four pairs of return rollers 36a, 36b, 36c, and 36d arranged in the middle of the return path. The exit of the end return path 35 c communicates with a conveyance path to the standby conveyance roller pair 28 corresponding to the sheet feeding cassette 24 below the sheet feeding unit 6.

  The electrical component 10 includes a circuit board on which a control device, which will be described in detail later, is composed of a plurality of electronic components.

  In this example, a cleaning unit 37 is disposed on the upper surface of the intermediate transfer belt unit 5. The cleaning unit 37 comes into contact with the upper surface of the transfer belt 17 to scrape and remove the waste toner, and accumulates it in a temporary storage unit of a belt cleaner unit (not shown).

  Then, the cleaning unit 37 conveys the accumulated waste toner to the upper portion in the dropping cylinder by the conveying screw and sends it to the waste toner collecting container 23 through the dropping cylinder.

  As shown in FIG. 1, the image forming unit 2 does not directly transfer a toner image onto a conventional sheet, but an intermediate transfer belt on a sheet that is vertically conveyed by a standby conveying roller pair 28 to a secondary transfer unit. The toner image is transferred via the toner image 17.

  Therefore, during the maintenance process for recovering from a problem such as a paper jam occurring in the paper conveyance path, the intermediate transfer belt unit 7 is opened outward with a hinge (not shown) as a fulcrum, and the right side in FIG. It can be dealt with.

  In addition, since troubles such as paper jams do not occur in the arrangement section of the kits, the front door 20 is opened when attaching / detaching consumables such as kits concentrated on the left side of FIG. It is configured so that it is only necessary to replace a kit or a circuit board in the longitudinal direction.

  The image forming process in the image forming unit 2 is a normal electrophotographic toner image forming process (printing process), and can be switched between monochrome printing and decoloring toner printing. Except for this, there is no special processing, and thus the details of the image forming processing are omitted.

Next, the image scanner unit 3 will be described.
The image scanner unit 3 of this example has not only an image of a document but also a color erasing function for erasing a color erasable toner image formed on a sheet.

  The image scanner unit 3 includes a flat bed unit 38 and an ADF (Automatic Document Feeder) unit 39 as in a normal scanner. However, unlike the normal scanner, the ADF unit 39 of this example includes two paper feed trays 49 (49a, 49b).

  An original table made of a transparent glass plate is disposed on the upper surface of the flat bed portion 38. The lower surface of the paper discharge tray portion 42 of the ADF portion 39 is in contact with the upper surface of the flat bed portion 38 so as to be openable and closable.

  A handle (not shown in the cross-sectional view in FIG. 1) on the front surface of the paper discharge tray portion 42 is lifted up by hand and the ADF portion 39 is rotated upward so that the bottom surface of the paper discharge tray portion 42 is flat. When the engagement surface with the upper surface of the bed portion 38 is opened, the document table on the upper surface of the flat bed portion 38 is exposed.

  In addition, a sub-scanning direction scanning unit 43 including a belt with a blade and a shaft or a driving string and a rail is disposed on the inner bottom portion of the flat bed portion 38. In the sub-scanning direction scanning unit 43, a reading and erasing unit 44 composed of a long LED (light emitting diode) array and a long image sensor, which will be described in detail later, is movable to the left and right as indicated by a double-directional arrow a. Is retained.

  In addition, an operation panel (not shown in FIG. 1 because of a cross-sectional view) is disposed in front of the flat bed portion 38. The operation panel includes a display unit capable of touch input and a button unit including a plurality of buttons capable of mechanical input on an upper surface inclined slightly downward.

  On the other hand, the ADF unit 39 includes a swivel conveyance unit 48 at the left end of the paper discharge tray unit 42. Two paper feed trays 49 (49a, 49b) are mounted on the swivel conveyance unit 48. The two paper feed trays 49 are positioned above the paper discharge tray section 42 and arranged in two upper and lower stages.

  The lower paper feed tray 49a is disposed with a sufficient distance from the upper surface of the paper discharge tray section 42 so that a predetermined number of documents or sheets can be discharged and placed on the paper discharge tray section 42. The upper sheet feed tray 49b is disposed with a sufficient space from the upper surface of the sheet feed tray 49a so that a predetermined number of documents or sheets can be placed on the lower sheet feed tray 49a.

  The two paper feed trays 49 are respectively provided with lateral width regulating plates 51 (51a, 51b) that can be arbitrarily moved in the lateral direction on both sides thereof. The document or paper placed on the paper feed tray 49 is regulated by the lateral width regulation plate 51 and is not skewed, and is fed to the swivel conveyance unit 48.

  As shown in FIG. 1, the swivel conveying unit 48 is in contact with the paper feed belt 52 (52a, 52b) and the paper feed belt 52 provided at the paper feed end of the paper feed tray 49, and rotates in the reverse direction to rotate the document or A separating roller 53 (53a, 53b) that prevents double feeding of sheets and a standby roller pair 54 arranged downstream thereof are provided.

  Further, the swivel conveyance unit 48 is arranged at substantially equal intervals on the circumferential surface of the swivel conveyance roller 55 and the swivel conveyance roller 55 downstream of the standby roller pair 54, and is driven in pressure contact with the circumferential surface of the swirl conveyance roller 55. Three driven rollers 56 (56a, 56b, 56c) are provided.

  Further, the swivel conveyance unit 48 includes a long plate-like flat plate-like ceramic heater 57 disposed in contact with the peripheral surface of the swivel conveyance unit 48 between the first driven roller 56a and the second driven roller 56b. I have. In general, ceramic heaters are known for their small size and high thermal efficiency.

  The flat ceramic heater 57 heats the decolorable toner image on the paper before irradiating the decoloring light when the image of the decolorable toner formed on the paper is erased by the reading and decoloring unit 44. These are arranged to assist the erasing by the reading and erasing unit 44.

  Further, the swivel transport unit 48 includes a pair of paper discharge rollers 58 disposed between the paper feed end of the paper feed tray 49 and the left end of the paper discharge tray unit 42 downstream of the third driven roller 56c. Yes.

  The reading and erasing unit 44 described above with this position as the home position at a position on the flat bed 38 side between the second driven roller 56b and the third driven roller 56c of the swivel conveying unit 48. Is arranged.

Next, a control circuit including the control device stored in the electrical unit 10 of the MFP 1 having the above configuration will be described.
FIG. 2 is a circuit block diagram including the control device of the MFP 1.

  As shown in FIG. 2, the circuit block is centered on a central processing unit (CPU) 60, and is connected to the CPU 60 via a data bus, an interface controller (I / F_CONT) 61, a printer controller (PR_CONT) 62, and a scanner. A controller (SC_CONT) 63 is connected.

  A printer printing unit 64 is connected to the PR_CONT 62 described above. Although not particularly shown, the printer printing unit 64 is connected to a belt driving unit, a transport mechanism driving unit, an applied voltage output unit, and the like.

  Further, the SC_CONT 63 is connected to the image scanner unit 3, the flat plate ceramic heater 57, and the tray switching unit 59 shown in FIG. 1. A reading and erasing unit 44 is connected to the image scanner unit 3, and an LED light source 65 and an image sensor 66 are connected to the reading and erasing unit 44.

  When one of the tray switching units 59 is driven so that the sheet feeding belt 52a and the separating roller 53a of the sheet feeding tray 49a and the sheet feeding belt 52b and the separating roller 53b of the sheet feeding tray 49b are exclusively driven. The other drive is stopped, and when the other is driven, switching is performed so that one drive is stopped.

  Also connected to the CPU 60 are a ROM (read only memory) 67, an EEPROM (electrically erasable programmable ROM) 68, an operation panel 70 of the main body operation unit, and a sensor unit 69 to which outputs from the sensors arranged in the respective units are input. Has been. The ROM 67 stores a system program, and the CPU 60 performs processing by controlling each unit according to the system program.

  That is, in each unit, first, the I / F_CONT 61 converts print data supplied from a host device such as a personal computer into bitmap data and develops it in the frame memory 71. In the frame memory 71, a storage area is set for each of black (K), magenta (M), cyan (C), yellow (Y), and decolorizable toner (R), and image data for each toner corresponds. It is expanded to the area to be.

  The data expanded in the frame memory 71 is output to the PR_CONT 62 and is output from the PR_CONT 62 to the printer printing unit 64.

  The printer printing unit 64 is an engine unit, and under the control of the PR_CONT 62, the rotational drive system including the photosensitive drum 9, the primary transfer roller 22 and the like shown in FIG. 1, the charging roller 12, the optical writing head 13, and the like. A drive output to a process load such as an applied voltage of an image forming unit having a driven portion is controlled.

  Further, although not shown in the drawing, the printer printing unit 64 includes a belt driving unit that performs the vertical movement of the intermediate transfer belt unit 5, the rotation driving of the transfer belt 17, the belt driving of the belt type fixing device 31, and the paper take-out roller 25. Controls drive output to a transport mechanism drive unit that drives a transport mechanism that is composed of various parts that are rotationally driven, such as the paper discharge roller pair 34.

  The data of each color of black (K), magenta (M), cyan (C), yellow (Y) or decolorable toner (R) output from the PR_CONT 62 corresponds from the printer printing unit 64, respectively. 1 is supplied to the optical writing head 21 shown in FIG.

  SC_CONT 63 indicates that when an input event output from operation panel 70 instructs reading of a document, the document is placed on paper feed tray 49 according to a detection signal output from sensor unit 69, or It is checked whether the flatbed portion 38 is placed on the document table, the LED light source of the reading and erasing unit 44 is set to the reading mode, and each unit is controlled to execute reading of the document.

  When SC_CONT 63 is designated to be erased by an input event output from the operation panel 70, a sheet to be erased on which an image of an erasable toner is formed is placed on the paper feed tray 49. Each unit is set to execute the decoloring by setting the LED light source of the reading and decoloring unit 44 to the decoloring mode, driving the plate-like ceramic heater 57 to generate heat, and driving the swivel conveyance unit 48. To control.

  3A is a diagram for explaining the configuration and operation of the reading and erasing unit 44, FIG. 3B is a diagram showing the LED light source and the lens configuration of the reading unit, and FIG. It is sectional drawing which expands and shows a basic composition typically.

  As shown in FIG. 3 (a), the reading and erasing unit 44 includes a unit frame 72 having a flat U-shaped cross section, and a long LED fixedly mounted in the unit frame 72. An LED light source 65 formed of an array, an SLA (Selfoc (registered trademark) lens array) 73, a CCD (Charge Coupled Device) chip 74 and an image sensor 66 formed of a substrate 75 are included.

  The operation relationship between the document 78 on the document table 77 and the reading and erasing unit 44 shown in FIG. 3A is that when the document 78 is placed on the flat bed 38, the document 78 is fixed. The reading and erasing unit 44 moves to the left and right as indicated by the double arrow a shown in FIG.

  On the other hand, when the document 78 is placed on the paper feed tray 49, the reading and erasing unit 44 is fixed at the home position shown in FIG. 1, and the document 78 is swirled and transported by the swivel transport unit 48. It passes over the platen 77 corresponding to the position position.

  In either case, the light emitted from the LED light source 65 to the image forming surface of the document 78 via the document table 77 as indicated by the arrow b is reflected as indicated by the arrow c and enters the SLA 73.

  As shown in FIG. 3B, the LED light source 65 is a long LED array in which three primary color LED chips 79 (red 79r, green 79g, blue 79b) are arranged on a long substrate 82, as will be described later. Each LED chip can be controlled to be turned on independently.

  In the figure, the arrangement of the LED chips is rough, but in actuality, they are arranged at the same density as the LED array of the optical writing head 13. However, it is an LED having a wide irradiation angle rather than an irradiation angle in an acute angle narrowed to a narrow range like the LED of the optical writing head 13.

  FIG. 3 (c) schematically shows the individual basic configuration of each of the three primary color LED chips 79, taking a single LED as an example. The LED shown in FIG. 3C is a light emitting device in which one electrode is fixed to a terminal of two lead wires 82 (82a, 82b) and one lead wire 83a via a conductive adhesive 83. 84 and a gold wire 85 that connects the other electrode of the light emitting element 84 and the terminal of the other lead wire 83 b are embedded in the epoxy resin 86.

  Irradiation light due to light emission of the light emitting element 84 is irradiated from the radiation surface 87 of the epoxy resin 86 in a range that forms an obtuse angle with a spread width 88 (88a, 88b).

  By selecting the light emitting elements 84 of the plurality of LED chips having such a basic configuration, a linear light source in which the LED chips 79 including the light emitting elements 84 having a desired wavelength from a short wavelength to a long wavelength are arranged in a desired order can be obtained.

  For example, a white light source can be obtained by combining three-wavelength (three primary colors) LED chips of light-emitting elements 84 having different blue, green, and red colors. Further, light sources having different wavelengths can be obtained by controlling switching points of individual LED chips.

  Therefore, paying attention to this principle, in this example, by constructing an LED light source module that combines an LED chip (red 79r) having a central emission wavelength in the near infrared region on the red side and a wide half-value width, it can be used for document illumination. Is configured so that light irradiation with a center wavelength of, for example, 817 nm can be performed as white light and decoloring light.

  On the other hand, the SLA 73 shown in FIGS. 3 (a) and 3 (b) is a long plate-like lens array in which a large number of gradient index rod-shaped lenses are arranged, and an enlarged image of incident light is arranged at the bottom. Project to the image sensor 66.

  Thereby, the image in the main scanning direction of the document is read, and the image in the sub-scanning direction is read by relatively moving the document 78 and the reading and erasing unit 44.

  The MFP 1 of this example can copy characters and images read from the document 78 in the image forming unit 2 using the paper stored in the paper feed cassette 24.

  Further, in the image forming unit 2 using the paper stored in the paper feed cassette 24 based on image information including a print instruction command input by wire / wireless from a host device (not shown) such as a personal computer. Monochrome texts can be printed, and full-color images can be printed (hereinafter, including printing).

  In addition to monochrome printing and full-color printing, the image forming unit 8K and the image forming unit 8R are replaced and mounted, so that the paper stored in the paper feed cassette 24 is used to erase with the decolorable toner (R). A chromatic toner image can be formed.

  Then, after using the paper on which the erasable toner image is formed, the erasable toner image that is no longer necessary can be erased from the paper. When erasing the color, the paper is placed on the paper feed tray 49 of the ADF unit 39 of the image scanner unit 3 with the erasable toner image forming surface facing upward.

  When a decoloring instruction is input from the selection button displayed on the button unit or the display unit of the operation panel 70, the decoloring is started. In this case, the reading and erasing unit 44 shown in FIG. 3A is fixed at the home position shown in FIG.

  The paper 91 to be erased is swirled and transported by the swivel transport unit 48 and passes over the document table 77 corresponding to the home position. At this time, under the control of SC_CONT 63, the swivel conveying roller 55 rotates counterclockwise, and the flat ceramic heater 57 is driven to generate heat.

  The decolorizable toner forming the decolorable toner image on the paper 91 is softened by heating from the flat plate ceramic heater 57, and the decolorability by light irradiation is improved. The erasable toner image having improved erasability is irradiated with erasable light having a center wavelength approximate to near-infrared light from the red 79r LED chip of the LED light source 65 of the reading and erasing unit 44.

  FIG. 4 is a wavelength comparison diagram with a halogen lamp for explaining the light emission characteristics of a red 79r LED chip having a center wavelength approximate to near-infrared light in the configuration of the LED light source 65. As shown in the figure, the emission wavelength 92 of the halogen lamp has a wide wavelength distribution ranging from about 400 nm to over 1100 nm. For this reason, as described above, there are problems such as a rise in temperature in the apparatus main body due to generation of light having a wavelength unnecessary for decoloring and large power consumption.

  On the other hand, the red 79r LED chip having a central wavelength approximate to the near-infrared light of the LED light source 65 used in the first embodiment is configured by an LED array, and the other three primary color LED chips (green 79g, blue 79b). ) And switching can switch the light emission drive.

  As shown in FIG. 4, the emission wavelength 93 of the LED has a very narrow wavelength distribution. That is, the LED is considered to generate very little light having a wavelength unnecessary for decoloring depending on the selection. Also, LEDs are well known for their high efficiency of electricity / light conversion and not generating large heat.

  Therefore, in this example, in order to correspond to the infrared photosensitive dye that is also used for the three primary colors red and has a sensitivity to 817 nm of the decolorizable toner, a red 79r LED chip with a center wavelength of 830 nm having a slightly wide wavelength distribution at half width is used. The LED light source 65 is arranged side by side with the green 79g and the blue 79b.

  FIG. 5 is a diagram for explaining light emission control of the LED light source 65 employed in this example. In FIG. 5, in order to clearly show the principle of control, the positional relationship among the document 78 (or paper 91), the LED light source 65, and the image sensor 66 is shown differently from the case of FIG.

  As shown in FIG. 5, a light emission drive wiring 94 is connected to each individual LED chip of the three primary color LED chips 79 of the LED light source 65. From the SC_CONT 63, a light emission drive wiring 94 to which power is supplied is selected by a light emission color switching signal 95 input to the LED light source 65 via the image scanner unit 3 and the reading and erasing unit 44.

  As a result, when reading the document 78, all the LEDs of the three primary color LED chips red 79r, green 79g, and blue 79b are driven to emit light, and white light is emitted from the LED light source 65 to the document 78. The reflected light is input to an image sensor 66 composed of a monochrome CCD, and a luminance signal 96 is output from the image sensor 66 to SC_CONT 63.

  The SC_CONT 63 generates the color tone and density of the image read from the document 78 by combining the time-division emission color switching signal 95 and the luminance signal 96 and notifies the CPU 60 of it.

  On the other hand, when erasing the erasable toner image on the paper 91 on which the erasable toner image is formed, a red 79r LED chip having a center wavelength approximate to near-infrared light is driven to emit light. At this time, the electric power supplied for the light emission driving is more than the power for driving the light emission of the three primary color LED chips 79r, 79g, 79b to emit white light, and the light quantity of the red 79r LED chip is increased. To increase.

  As shown in FIG. 3C, the irradiation angle of the light emitting element of the LED chip used in the LED light source 65 is wide and has a spread to irradiate the front area of one adjacent light emitting element. As a result, it is possible to erase the color-erasable toner image in the front area of the LED chips of green 79g and blue 79b that are not lit.

  As described above, in the tray switching unit 59, under the control from the SC_CONT 63, the sheet feeding belt 52a and the separating roller 53a of the sheet feeding tray 49a and the sheet feeding belt 52b and the separating roller 53b of the sheet feeding tray 49b are exclusive. It is provided so as to switch the drive.

  Thus, for example, when an urgent document reading operation occurs when a plurality of sheets on which a color erasable toner image is formed is placed on the sheet feeding tray 49a, A person who performs a reading operation can place an original on the paper feed tray 49b, operate the operation panel to interrupt the decoloring operation, and instruct the original to be read.

  When instructed to interrupt the erasing operation and start document reading, the tray switching unit 59 switches the control from the drive control of the paper feed tray 49a to the control of the paper feed tray 49b. The reading and erasing unit 44 switches light emission of the three primary color LED chips 79 from light emission for erasing to light emission for reading.

  When the document reading operation is completed, the person who performed the document reading operation operates the operation panel to instruct to resume the erasing operation. The drive control to the paper feed tray 49b is stopped, the drive control of the paper feed tray 49a is started, and the erasing operation is resumed.

  It should be noted that switching can be performed in the same manner even when an erasing operation that requires urgent action occurs while performing a document reading operation. In this way, it is possible to immediately perform the other task that requires urgent without changing the mode of one of the tasks, to efficiently perform the task that requires urgentness, and to interrupt immediately when the task that requires urgentness is completed. Work can be resumed.

  The light emitting element of the red 79r LED chip used for the LED light source 65 has a center wavelength of 750 nm, and a near-infrared LED chip having a center wavelength of 817 nm and a half-value width of 50 nm is alternately arranged with the three primary color LED chips. It may be used while switching the drive side by side.

  6A and 6B are diagrams showing an example of the shape of the ceramic heater employed in the MFP 1 of the present invention and disposed on the swivel conveyance unit 48 of the ADF unit 39 and an example of how to use it.

  As described above, in the first embodiment, the example in which the long plate-like flat plate ceramic heater 57 is used as the ceramic heater as shown in FIG. 6A is shown. However, the ceramic heater is limited to a flat plate. For example, a long rod-shaped round bar-shaped ceramic heater 94 shown in FIG. 6B may be used.

  In addition, when using either the flat ceramic heater 57 or the round bar ceramic heater 94, the flat ceramic heater 57 and the round bar ceramic heater 94 are arranged so as to contact the peripheral surface of the swivel conveying roller 55 as shown by solid lines in FIGS. 6 (a) and 6 (b). Alternatively, as shown by a broken line in FIGS. 6A and 6B, the rotating conveyance roller 55 may be disposed so as to be in contact with the peripheral back surface.

  The present invention is applied to a multifunctional image forming apparatus with a toner erasing function that can immediately perform the erasing processing operation and the original reading operation without changing the mode of one of the operations, and the other urgent operation. can do.

1 Multifunctional image forming device (MFP) with toner decoloring function
2 Image forming unit 3 Image scanner unit 4 Image forming unit unit 5 Intermediate transfer belt unit 6 Paper feeding unit 7 Double-sided printing transport unit 8 (8M, 8C, 8Y, 8K) Image forming unit 9 (7m, 7c, 7y, 7k) ) Photosensitive drum 10 Electrical section 11 Cleaner 12 Charging roller 13 Optical writing head 14 Developer 15 Developing roller 16 Supply roller 17 Transfer belt 18 Drive roller 19 Driven roller 21 Belt position control mechanism 22 Primary transfer roller 23 Waste toner collection container 24 Paper cassette 25 Paper take-out roller 26 Feed roller 27 Rolling roller 28 Standby conveyance roller pair 29 Secondary transfer roller 31 Belt-type heat fixing device 32 Unload roller pair 33 Paper discharge tray 34 Paper discharge roller pair 35a Start return path 35b Intermediate return Road 35c Terminal return path 36a, 36b, 36 , 36d Return roller pair 37 Cleaning unit 38 Flat bed unit 39 ADF (Automatic Document Feeder) unit 42 Paper discharge tray unit 43 Sub-scanning direction scanning unit 44 Reading and erasing unit 48 Revolving conveyance unit 49 (49a, 49b) Paper feed tray 51 (51a, 51b) Width regulating plate 52 (52a, 52b) Paper feed belt 53 (53a, 53b) Rolling roller 54 Standby roller pair 55 Revolving conveyance roller 56 (56a, 56b, 56c) Driven roller 57 Flat ceramic heater 58 Paper discharge roller pair 60 CPU (central processing unit)
61 Interface controller (I / F_CONT)
62 Printer controller (PR_CONT)
63 Scanner controller (SC_CONT)
64 Printer printing section 65 LED (light emitting diode) light source 66 Image sensor 67 ROM (read only memory)
68 EEPROM (electrically erasable programmable ROM)
69 sensor unit 70 operation panel 71 frame memory 72 unit frame 73 SLA (Selfoc (registered trademark) lens array)
74 CCD (Charge Coupled Device) chip 75 substrate 77 document table 78 document 79 three primary color LED chips 79r red 79g green 79b blue 81 long substrate 82 (82a, 82b) lead wire 83 conductive adhesive 84 light emitting element 85 gold wire 86 epoxy Resin 87 Radiation surface 88 (88a, 88b) Spreading width 91 Paper 92 Light emission wavelength of halogen lamp 93 Light emission wavelength of LED 94 Round bar ceramic heater

Claims (1)

Document conveying means;
Light irradiating means for irradiating a predetermined light beam on the image surface of the document conveyed by the document conveying means;
Reading means for reading an image of the document;
An image reading unit having
An image forming unit that forms a decolorable toner image or a normal toner image on a sheet by electrophotography;
Comprising at least
A multifunctional image forming apparatus with a toner erasing function having a toner erasing function for erasing the erasable toner image formed on the paper via the image reading unit,
A plurality of paper feed trays for supplying the original or the paper to the original conveying means;
A multifunctional image forming apparatus having a toner erasing function.