JP2010282121A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus having constitution to perform decolorizing and reproducing/recording from/to a desired surface by selecting either one surface or both surfaces and decolorizing thereon when images are carried on both surfaces of a recording medium. <P>SOLUTION: The image forming apparatus that can form the images on both front and back surfaces of the recording medium by using developer achieving reversible reaction of color development and decolorizing includes a heating roller 101 and a pressure means 102 opposed to each other across a recording medium conveyance path. The pressure means 102 can be displaced to a position where it is opposed to the heating roller 101 and can hold and convey the recording medium and a position where it separates from the heating roller and does not hold and convey the recording medium. When decolorizing the image carried on one surface of the recording medium, opposing relation of the pressure means 102 to the heating roller 101 is set to provide a gap δ corresponding to the thickness of the recording medium when the pressure means moves to the position where it can hold and convey the recording medium. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an image forming apparatus, and more particularly to a decoloring mechanism for a decolorable ink or developer.

  In recent years, with the spread of OA, the data processing amount of various types of information tends to increase rapidly, and printing machines and copiers used for outputting such information also increase the consumption of paper as a recording medium. It is said that there is a problem from the viewpoint of so-called resource protection.

  In view of this, it has been proposed to use a erasable developer, particularly toner or ink, in an electrophotographic recording or ink-jet printing recording, etc., so that the recording medium can be repeatedly used (for example, Patent Documents). 1, 2).

  Patent Document 1 discloses an image forming apparatus using a reversible thermal recording ink whose color tone reversibly changes depending on temperature. Patent Document 2 uses an ink that can be erased by heat. In addition, a printer capable of decoloring an image formed with the ink by heating it using a heat roller or a thermal head is disclosed.

  On the other hand, as a configuration in which new recording is performed after erasing, a heating source is provided on the upstream side in the moving direction of the recording medium in the same manner as in Patent Document 2 above, and after the erasing by the heating source, the recording head is again performed. There has also been proposed a configuration in which recording is performed according to (for example, Patent Document 3).

  In Patent Document 3, a color developer, a developer, and an ink obtained by dissolving or decomposing a color erasing agent in a solvent are used, and color is developed by a chemical bond between the color developer and the developer at a room temperature of 40 ° or less. A structure is disclosed in which recording is possible again by causing the chemical bond between the developer and the color erasing agent to become colorless by disintegrating the chemical bond at a high temperature of 100 ° or more.

The configuration disclosed in the above-mentioned patent document has an advantage that the recording medium can be reused by erasing the image, but has the following problems depending on the form of image formation.
As a form of image formation, there are cases where not only one side of a recording sheet used as a recording medium but also both sides are targeted.
On the other hand, only one of the images carried on both sides of the recording paper may be erased. In this case, the image on one side is erased by heating from the target one side. become.

  However, since heat is transferred to the back side of the recording paper by heating from one side, the image carried on the back side is also affected by the heat, and the chemical bond with the developer corrosion material is generated and the color is erased. There is a risk. For this reason, even if only the image carried on one side of the recording paper is erased and new recording is performed, decoloring may occur on both sides and the paper may return to a blank state.

  An object of the present invention is to select either one side or both sides when the image is carried on both sides of the recording medium in the case of using the conventional image forming apparatus, particularly, decolorable toner or ink. Another object of the present invention is to provide an image forming apparatus having a configuration capable of erasing / reproducing / recording on a desired surface by erasing.

In order to achieve this object, the present invention has the following configuration.
(1) In an image forming apparatus capable of forming an image on both front and back surfaces of a recording medium using a developer capable of reversible color development and decoloration,
A heating roller and a pressure unit facing each other across the conveyance path of the recording medium,
The pressurizing means is displaceable to a position where the recording medium can be nipped and conveyed facing the heating roller, and a position where the recording medium is not nipped and conveyed away from the heating roller. When the image carried on one side of the sheet is decolored, when the image is moved to a position where it can be nipped and conveyed, a gap corresponding to the thickness of the recording medium is provided so as to be opposed to the heating roller. An image forming apparatus.
(2) In an image forming apparatus capable of forming an image on both front and back surfaces of a recording medium using a developer capable of reversible color development and decoloration;
A heating roller and a pressure unit facing each other across the conveyance path of the recording medium;
A gap detection means provided on the pressure means side for detecting a gap facing the pressure roller with respect to the heating roller;
A gap adjusting means provided on the pressure means side, wherein the pressure means is brought into contact with and separated from the heating roller between a holding conveyance position of the recording medium and a position where the holding conveyance is not performed;
A gap control unit provided on the pressure unit side, wherein a gap detection unit for detecting a facing gap of the pressure unit with respect to the heating roller is connected to the input side, and the gap adjustment unit is connected to the output side. And
The gap control unit corresponds to the thickness of the recording medium as a displacement amount for displacing the pressurizing unit to the nipping and conveying position of the recording medium when the image carried on one side of the recording medium is decolored. An image forming apparatus, wherein the gap adjusting means is driven and controlled to set a facing interval with a gap so as to face the heating roller.
(3) The image forming apparatus according to (2), wherein a pressure roller is used as the pressure unit, and a heater is built in the pressure roller.
(4) A heating roller and a pressure roller used in a fixing device equipped when an electrophotographic system is used are used as the heating roller and the pressure unit. (1) to (3) The image forming apparatus according to any one of the above.
(5) In an image forming apparatus capable of forming images on both front and back surfaces of a recording medium using a developer capable of reversible color development and decoloration,
An image forming apparatus, wherein members capable of selecting a heating function and a cooling function are arranged on both sides of the conveyance path of the recording medium.
(6) The image forming apparatus according to (5), wherein the member capable of selecting the heating function and the cooling function includes a blower that supplies heated air or cooling air to the recording medium. .
(7) The transport path of the recording medium is provided with an electrophotographic image forming unit and a printing image forming unit, and the developer erasing unit is provided between the image forming units. The image forming apparatus as described in (5) or (6) above.
(8) The image forming apparatus according to (7), wherein a heating member provided in the fixing device is used as the member having a heating function in the electrophotographic image forming unit.
(9) The image forming unit according to (7), wherein the electrophotographic image forming unit uses a member facing the heating member provided in the fixing device as a member having a cooling function. apparatus.
(10) The image forming apparatus according to any one of (1) to (7), wherein the recording medium is provided with an identification unit that identifies erasability.
(11) The identification unit that is provided on the recording medium and that is erasable is detected by a detection unit provided on the conveyance path of the recording medium and is used to determine whether or not erasing control is possible. The image forming apparatus as described in (10) above.
(12) In an image forming apparatus capable of forming an image on both front and back surfaces of a recording medium using a developer capable of reversible color development and decoloration,
A heating roller and a pressure unit facing each other across the conveyance path of the recording medium,
The pressurizing unit is composed of a pair of rollers arranged in the circumferential direction on the heating roller, and is selectively and pressure-contacted and separated from the heating roller independently. .
(13) One pressing roller used for the pressing unit can be controlled to be pressed and separated independently from a cooling member provided separately from the heating roller. (12) The image forming apparatus described in 1.
(14) The image forming apparatus according to (12) or (13), wherein a heater is incorporated in the pair of pressure rollers.

  According to the present invention, it is possible to decolor an image on one side of a recording medium on which images are formed on both sides. In other words, the pressure means provided opposite the heating roller is set so as not to be affected by the heat from the heating roller, so that the back surface of the recording medium facing the heating roller is heated. Therefore, it is possible to erase the image on only one side without erasing the image on the back surface. Further, the pressurizing means is provided with a heating source, so that the color can be erased on both the front and back sides of the recording medium.

  Furthermore, in the present invention, during the decoloring operation on one side of the recording medium, a temperature control member capable of selecting a heating function and a cooling function is provided on both sides across the conveyance path of the recording medium, so that the opposite to the heating on one side. Due to the cooling effect on the side surface, heat transfer to the back surface of the decolored surface of the recording medium can be prevented, and decoloring on one side can be performed reliably.

  Further, in the present invention, by providing a pair of pressure rollers that can be pressed and separated independently along the circumferential direction of the heating roller as the pressure unit, one pressure roller is used for nipping and conveying the recording medium. Since the other pressure roller is spaced apart when it is being used, the pressure roller can be used as a new cooling member by alternately contacting the pair of pressure rollers to the heating roller side. Even when a recording medium to be decolored on one side is continuously conveyed, the surface opposite to the decolored surface is prevented from being heated, and decoloring of one side can be performed reliably.

It is a schematic diagram for demonstrating the structure of the decoloring apparatus used for the image forming apparatus by this invention. It is a schematic diagram for demonstrating the structure applied to the decoloring apparatus shown in FIG. It is a schematic diagram for demonstrating the use condition of the decoloring apparatus shown in FIG. It is a flowchart for demonstrating the effect | action implemented by the control part used for the decoloring apparatus shown in FIG. It is a schematic diagram for demonstrating the modification of the erasing apparatus shown in FIG. It is a schematic diagram for demonstrating the principal part modification of the erasing apparatus shown in FIG. It is a schematic diagram for demonstrating an example of the structure used for the heating and cooling used for the structure shown in FIG. It is a schematic diagram for demonstrating an example of the structure which performs heating among the heating and cooling shown in FIG. It is a schematic diagram which shows the modification of the member which gave the heating and cooling function shown in FIG. FIG. 7 is a schematic diagram illustrating a modification of the image forming apparatus using the decoloring apparatus illustrated in FIG. 6. FIG. 7 is a schematic diagram illustrating still another example of an image forming apparatus using the erasing apparatus illustrated in FIG. 6. FIG. 11 is a diagram for explaining the contents of erasing / reproducing recording when the image forming apparatus shown in FIG. 9 or 10 is used. It is a table | surface figure which shows the experimental result of the decoloring state by the heating temperature and cooling temperature at the time of performing single-sided decoloring in a decoloring apparatus. It is a table | surface figure which shows the experimental result of the decoloring state using conditions different from the conditions shown in FIG. It is a schematic diagram for demonstrating the principal part modification of the decoloring apparatus shown to FIG. 1 and FIG. It is a schematic diagram for demonstrating the structure of the decoloring apparatus by another embodiment of this invention. It is a schematic diagram which shows the one aspect | mode of the pressure roller which can be used for the structure shown in FIG. It is a schematic diagram which shows the other aspect of the pressure roller used for the structure shown in FIG. It is a schematic diagram which shows the standby state of the pressure roller used for the structure shown in FIG. FIG. 17 is a schematic diagram illustrating an aspect in the case where the pressure roller used in the configuration illustrated in FIG. 16 erases the first recording sheet. FIG. 17 is a schematic diagram illustrating an aspect in the case where the pressure roller used in the configuration illustrated in FIG. 16 erases the first and subsequent recording sheets. FIG. 21 is a flowchart for explaining the operation of the pressure roller shown in FIGS. It is a schematic diagram for demonstrating the cooling structure of the pressure roller used for the structure shown in FIG. It is a schematic diagram which shows the standby state of the pressure roller in the structure shown in FIG. FIG. 24 is a schematic diagram illustrating a state in which a first recording sheet is decolored by a pressure roller in the configuration illustrated in FIG. 23. FIG. 24 is a schematic diagram illustrating a state in which erasing is performed on the first and subsequent recording sheets by the pressure roller in the configuration illustrated in FIG. 23.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.
FIG. 1 is a schematic diagram showing the configuration of a decoloring apparatus used in an image forming apparatus according to the present invention. In FIG. 1, the decoloring apparatus 100 is a recording sheet used as a recording medium as shown in FIG. A fixing device having a heating roller 101 and a pressure roller 102 facing each other across the conveyance path is used. Therefore, the toner used as the developer used in this case is targeted.

  A fixing device used as the erasing device 100 is configured such that a pressure roller 102 is in pressure contact with a heating roller 101 located on one side of a recording paper conveyance path using an elastic body 103 such as a spring. Thus, the toner image (referred to as an unfixed image in FIG. 2 for the sake of convenience) carried on the recording paper S by the heating roller 101 is heated and fixed while the recording paper is nipped and conveyed.

  On the other hand, in FIG. 1, the decoloring apparatus 100 is configured such that the pressure roller 102 used as the pressure unit is controlled to face the heating roller 101.

  In FIG. 1, the pressure roller 102 is provided with a gap adjusting means 104 for adjusting a facing gap with the heating roller 101.

  The gap adjusting means 104 is configured by an L-shaped swing link having a fulcrum pin 104A as a fulcrum, and detects a gap, that is, a so-called gap between the pressure roller 102 and the heating roller 101 at one of the swing ends. A gap detecting means 105 using a stroke sensor or the like is arranged opposite to each other, and an eccentric cam 106 for swinging driving is arranged on the other end of the swinging end with its peripheral edge in contact.

  The gap adjusting means 104 can oscillate according to the rotational phase of the eccentric cam 106, and as shown in FIG. 3, the gap is not separated from the heating roller 101 and the recording paper S is not nipped and conveyed (FIG. 3A). )), Facing the heating roller 101 with a gap corresponding to the thickness of the recording paper S (indicated by the symbol δ in FIG. 1 and indicated as sheet thickness in FIG. 3). A state in which the recording paper S can be nipped and conveyed (see FIG. 3B) and a state in which the recording paper can be nipped and conveyed by directly contacting the heating roller 101 (see FIG. 3C) are selected. It has become.

  Of the oscillating ends of the oscillating links used as the gap adjusting means 104, an oscillating end located on the pressure roller 102 side is formed with an elongated hole through which the support shaft 102A of the pressure roller 102 is inserted. The pressure roller 102 can be moved toward and away from the heating roller 101 when it is swung.

  The eccentric cam 106 is controlled in rotational phase by a drive motor 107, and the rotational phase is set by a gap control means 108 that connects the drive motor 107 to the output side.

  The gap control means 108 has a gap detection means 105 and a temperature sensor 109 for detecting the surface temperature of the heating roller 101 connected to the input side, and a drive motor 107 connected to the output side.

  In the gap control means 108, when the decoloring operation of the image carried on the recording paper is selected, the surface temperature of the heating roller 101 has reached a temperature at which the developer used in the image can be decolored. At this point, the pressure roller 102 is displaced toward the heating roller 101 with a gap corresponding to the thickness of the recording paper.

  The thickness of the recording paper in this case is the type of recording paper input on an operation panel (not shown) or information from a thickness detection sensor (not shown) provided in the recording paper conveyance path.

  When the surface temperature of the heating roller 101 necessary for erasing is set, the drive motor 107 sets the rotation phase amount (rotation amount) by a signal from the gap control means 108, and the gap adjustment means 104 is interlocked with this rotation. Oscillates so that the pressure roller 102 is opposed to the heating roller 101 at a position where the recording paper S can be nipped and conveyed.

  As a result, the pressure roller 102 does not face the heating roller 101 until the temperature on the side of the heating roller 101 reaches a temperature at which the color can be erased, so that the pressure roller 102 is not easily affected by the heat from the heating roller 101. It is said. Since the heating roller 101 does not face or abut against the pressure roller 102 until the temperature at which the color can be erased is reached in this way, heat is not deprived to the pressure roller 102 side. The temperature rise at can be accelerated.

  On the other hand, the pressure roller 102 faces the heating roller 101 when the surface temperature on the side of the heating roller 101 reaches a temperature at which the color can be erased. It is not affected by. In addition, when facing each other, a gap corresponding to the thickness of the recording paper is set to face each other. Therefore, when the recording paper is nipped and conveyed, the heat conduction from the heating roller 101 to the pressure roller 102 is also achieved. Is less likely to be affected by heat from the heating roller 101 side.

  As a result, when the color is erased on one side of the recording paper S, the temperature rise on the back side of the recording paper is reduced, and the color erasing operation on only one side becomes possible.

FIG. 4 is a flowchart for explaining the operation of the gap control means 108. In FIG. 4, the pressure roller 102 is separated from the heating roller 101 at the time of initialization (ST1).
When the operation mode is input, the erasing apparatus 100 determines the mode, and determines whether it is a erasing operation or a fixing operation during normal image formation (ST2).

  If the result of determination in step ST2 is decoloring work, the temperature of the heating roller 101 of the decoloring apparatus 100 is set to a decolorable temperature and the temperature is monitored (ST3, 4).

  When the surface temperature of the heating roller 101 reaches a decolorable temperature, the drive motor 107 is driven according to the rotation amount set in the gap control means 108 and the eccentric cam 106 is rotated, and the gap adjusting means 104 is swung. As a result, the pressure roller 102 faces the heating roller 101 side with a gap corresponding to the thickness of the recording paper S (ST6).

  When the pressure roller 102 is opposed to the heating roller 101, the recording paper S that is nipped and conveyed by these rollers decolors the image carried on one side thereof, that is, the surface facing the heating roller 101.

  Since the pressure roller 102 is in contact with the heating roller 101 at a low temperature on the surface opposite to the surface carrying the image to be erased, the image is erased due to the temperature rise on only one surface. Will be.

  On the other hand, during normal fixing work, the heating roller 101 is set to the heating and fixing temperature, and the temperature is monitored (ST8, 9).

  When the heat fixing temperature is reached, the pressure roller 102 is opposed to the heat roller 101 side by the gap adjusting means 104 as described above. In this case, the pressure roller 102 is in direct contact with the heat roller 101. (ST10). When both rollers come into contact with each other and are ready for nipping and conveying the recording paper, it is notified that the preparation for the fixing operation has been completed (ST11).

  In the above embodiment, when the erasing operation is performed only on one side of the recording paper, the heating roller used for erasing is heated away from the pressure roller. In addition to being accelerated, heat conduction to the pressure roller is unlikely to occur, so that the temperature of the pressure roller does not increase carelessly. In the present embodiment, the decolorable temperature is desirably 60 ° to 80 °, and one side carrying an image to be decolored and the opposite side carrying an image not to be decolored It is desirable that the temperature difference with this surface is 30 ° to 40 °, and as described above, this temperature condition is achieved by preventing the pressure roller 102 from directly contacting the heating roller during the decoloring operation. Easy to get.

  In addition, when the pressure roller is opposed to the heating roller, a gap corresponding to the thickness of the recording paper is set and opposed, so unlike the case of direct contact, it is difficult to receive heat conduction from the heating roller. It is possible to prevent the temperature of the surface opposite to the surface of the recording paper to be erased from being increased, so that when an image is formed on both sides of the recording paper, It becomes possible to erase the color as a target.

  In this embodiment, the color erasing operation can be performed only by setting the facing relationship between the pressure rollers using a fixing device used in an electrophotographic image forming apparatus as the color erasing apparatus. It is not necessary to install a new erasing device, and the image forming apparatus can be prevented from being unintentionally enlarged.

Note that the configuration shown in FIG. 5 can be used as the configuration of the gap adjusting means 104.
In FIG. 5, the configuration shown in FIG. 5A is a configuration in which the eccentric cam 106 is brought into direct contact with the bearing 102A of the pressure roller 102 (contacted at a position indicated by symbol P in the drawing), and is shown in FIG. The configuration is such that the pressure roller 102 is provided in a unit 110 that can advance and retract relative to the heating roller 101, and the unit 110 is displaced by an eccentric cam 106.

  On the other hand, as described above, in addition to the case where the image is erased on one side of the recording paper by adjusting the gap of the pressure roller 102, the present embodiment is applied to the case where the decoloring operation is performed on both the front and back sides. In the embodiment, a heater is provided inside the pressure roller 102, and the temperature of the heater is set to a temperature that can be erased, whereby the image can be erased on both the front and back sides of the recording paper.

Next, another embodiment of the present invention will be described.
The feature of the present embodiment is that, firstly, the surface of the recording medium carrying the image to be erased is heated and the back surface thereof is cooled. In addition, it is possible to perform recording on the surface of the recording paper returned to the blank paper state, and thirdly, it is possible to determine whether or not the recording medium can be erased.

  FIG. 6 shows a decoloring device 200 that is a decoloring unit used in the image forming apparatus in order to explain the first feature. In FIG. 6, the decoloring device 200 is an electrophotographic image forming apparatus. The fixing device used in the above is used.

The first feature will be described for this configuration as follows.
A heating roller 201 used in the heat roller fixing method is provided on one surface across the conveyance path of the recording paper S used as a recording medium in the fixing device, and a pressure used in the fixing method is provided on the other surface. A roller is disposed as each cooling roller 202.

  In this configuration, the heating roller 201 and the pressure roller 202 face each other across the conveyance path of the recording paper S, so that the recording paper S can be nipped and conveyed.

  In this configuration, when one surface of the recording paper is to be erased, the heating roller 201 is set to a temperature at which the heating roller 201 can be erased, while the cooling roller 202 has a temperature difference of 30 ° to 40 ° with the heating roller 201. Is set to a temperature.

As a result, the recording paper S that contacts the heating roller 201 receives heat from the heating roller 201 and is cooled so that the opposite surface does not reach the decoloring temperature, so only one side is decolored. By the way, the recording paper has fine irregularities on its surface, and a uniform contact state with respect to the heating roller 201 and the cooling roller 202 may not be obtained.
FIG. 7 shows an example of a configuration used for heating in such a case. In FIG. 7, a configuration for supplying warm air and cooling air is provided on each of the front and back surfaces of the recording paper S. ing. In FIG. 7, reference numeral R1 denotes a recording paper transport roller, and the distance between these rollers is shorter than the length of the recording paper in the transport direction.

  As a configuration of the member for supplying the warm air or the cooling air to perform the temperature control for each surface of the recording paper, in the case of supplying the warm air in FIG. The blower fan 205 is used. Similarly, the air supply fan can be used in the configuration for supplying the cooling air. In this case, the outside air of the image forming apparatus is used as the cooling air.

  However, when supplying warm air and cooling air using the blower fan 205, a special structure such as a heater or intake of outside air that differs depending on the function is required.

Therefore, in this embodiment, it is possible to use a member that can be heated and cooled by a single member.
FIG. 9 shows the configuration in this case. In FIG. 9, a Peltier element 207 whose function is switched by switching the direction of the applied current is used for the heat source and the cooling source. The Peltier element 207 has a surface that protrudes to the air passage of the blower fan 205, and selects a function of heat generation and cooling on this surface.

  Warm air and cooling air generated by the Peltier element 207 are supplied to the recording paper by the blower fan 205, and erasing on one side of the recording paper becomes possible. According to such a configuration, even when the surface of the recording paper has irregularities, it is possible to spread the warm air over the entire surface, so that it is possible to prevent the occurrence of temperature unevenness on one side, and the Peltier element 207. When using, the hot air and cooling air can be switched instantaneously, so that the color erasing work surface changes for each continuously conveyed recording paper, unlike when only the heater is used. Can be easily handled.

  The warm air supplied by the blower fan is supplied during the decoloring operation for one side of the recording paper, and the blower fan 205 is stopped when the decoloring operation is not performed. Yes.

  Next, the second feature of the present embodiment will be described. The second feature is that recording can be performed again on the recording paper that has been returned to the blank state by erasing.

  FIG. 10 is a view showing one embodiment for explaining this feature. The image forming apparatus shown in FIG. 10 is an ink jet using an ink capable of reversible reaction of color development and decolorization as a developer. This is a printer 250.

  In FIG. 10, the ink jet printer 250 has a position before the recording paper reaches the ink jet head 253 in the recording paper conveyance path formed between the manual feed tray 251 and the paper discharge tray 252 provided in the housing. Is provided with a decoloring device 200 as a decoloring unit.

  In the ink jet printer 250, the recording paper fed from the paper supply unit 254 is printed by the ink jet head 253 in the process of being transported on the transport path, and is transported toward the paper discharge tray 252. In the figure, reference numeral 255 denotes a recording paper reversing mechanism used for image formation on both sides.

  The decoloring apparatus 200 for such a configuration is designed to perform a decoloring operation on one side of a recording sheet that reaches the ink jet head 253.

  In such a configuration, the recording paper carrying the image to be erased on one side is subjected to the erasing operation in the erasing apparatus 200, and then the recording paper returned to the blank state in the inkjet head 253 is used. It is printed again.

  In this case, for example, an ink jet head using an ink flying method using a piezo element is used for print recording.

  According to this configuration, recording can be performed again on the recording paper that has returned to the blank paper state, so that the recording paper can be reused without preparing a new recording paper.

  On the other hand, regarding the reproduction of the recording paper by the above-described erasing apparatus 200, for example, when the erasing operation is performed after the image formation by the electrophotographic method, and then the recording paper is returned to the blank paper state is recorded again There is also.

  FIG. 11 shows the configuration in this case, and the image forming apparatus 300 shown in FIG. 11 has a manual feed tray 251 and a paper discharge tray 252 provided in the housing, as in the case shown in FIG. A recording paper conveyance path is formed between the electrophotographic image forming unit including a photosensitive drum 303 used as a latent image carrier and an inkjet head (for convenience, as shown in FIG. 10). An image forming unit using a printing method provided with a reference numeral 253) is provided, and a decoloring device 200 is provided between the image forming units. Although the configuration of the electrophotographic image forming unit is not shown, a charging device, a writing device, a developing device, and a cleaning device are provided around the photosensitive drum 303, and the photosensitive paper is sandwiched between recording paper conveyance paths. A known configuration in which a transfer device is provided at a position facing the body drum 303 is used.

  As the developer used in the electrophotographic system, a developer containing a toner capable of reversible reaction of color development and color erasure is used. In this case, as the color erasing apparatus 200, the fixing apparatus shown in FIG. 6 is used.

  In this configuration, an image formed on one side of the recording paper in the electrophotographic image forming unit is erased on one side by the erasing apparatus 200, and the recording paper that has returned to the blank state is newly printed by the inkjet head 253. Is recorded.

  In this case, the erasing apparatus 200 is configured so that the set temperature of the heating roller 201 can be switched between fixing and erasing.

In the above configuration, the image can be rewritten by erasing the image, and there are the following cases as the use of single-sided rewriting.
In some cases, only the cover of text printed on both sides is changed. In addition, it can also be applied to store information cards, etc. In this case, if you fill in the map on the front and the person in charge and the reservation time on the back, you can rewrite only the map or the person in charge or the reservation time. Can be rewritten when changed. Such rewriting includes (1) full-color rewrite use and (2) EP + rewrite use.

  In the configuration shown in FIG. 10, since full-color rewriting can be performed using three color inks of cyan, yellow, and magenta, not only character information but also pictures and images can be rewritten. As an example of full-color rewriting applications, fitness clubs can be used for membership cards for rewriting personal menus at any time, card games at game centers, and the like. A wide range of uses as a rewritable printer can be obtained.

  In the configuration shown in FIG. 11, rewriting can be performed by a combination of electrophotography and inkjet. For example, as shown in FIG. 12, a work instruction sheet indicating the number of parts and the order of assembly in a high-mix low-volume production factory. There is a use for.

  12, the format portion (FIG. 12 (A-1)) is printed by electrophotography, and the necessary number of parts and assembly order are printed by rewritable ink (FIG. 12 (A-2)). Set the work instruction as one set and assemble the parts.When the parts are assembled, put them in the erase mode and rewrite them.

  On the other hand, FIG. 12B shows an example of the use in the case of using an ink capable of reversible reaction used as a developer. In FIG. 12B, thermoreversibility in which color is erased by heating and color is developed by cooling. The use of masking when using ink is shown. The use shown in the figure is, for example, a case where it is used as a test answer sheet having a question part of a test in a school or a cram school and an answer column. In this case, the rollers 201 and 202 used in the erasing apparatus 200 shown in FIG. 6 are configured so that both heating and cooling functions can be set unlike the case shown in FIG. A heat-erasable ink is used for the masking portion, and the original document portion is formed by electrophotography or friendship ink-jet.

Further, as the ink used in the present embodiment, ink having the following characteristics is used. When the image forming apparatus in which the erasing apparatus 200 and the inkjet head 253 shown in FIG. 10 are combined is targeted, the viscosity of the ink is 10 mPa · sec or less and the average particle size is targeted for ejection from the inkjet head 253. Is preferably 100 nm or less. Ink is colored at room temperature, and ink that is in a decolored state in a high temperature range with a predetermined temperature (discoloration point) as a boundary is used. When an ink whose erasing temperature (discoloration point) is not higher than the fixing temperature of electrophotography is used, a fixing roller can be used as a device for erasing the ink. The decoloring temperature is preferably 60 to 80 degrees.
Specific examples include those described in JP-B-51-44706, JP-B-51-44707, JP-B-1-29398, and the like.

  FIGS. 13 and 14 show the set temperatures of the heating and cooling rollers when the original on which double-sided printing has been performed with the thermal decoloring ink is used as the decoloring apparatus using the heat roll fixing system shown in FIG. It is a table | surface which shows the result of having changed and experimented the erased state in the surface and the back surface. In FIGS. 13 and 14, the result of the painted portion indicates a condition that only one side can be completely erased.

In this experiment, the following conditions are used.
Plain paper: TYPE 6200, thick paper: 359 g / m ² paper Ink: Fluorescent marker “friction line” yellow manufactured by Pilot Corp. What can be said from FIGS. If it is within the range, only one side can be erased. Considering that heat is transferred from the roller to the paper, it is better for the roller on the cooling side to be low temperature, but the larger the temperature difference is, the more difficult it is to maintain the difference. Is preferably as close as possible.

Next, the third feature will be described.
A third feature is that an identification unit is provided that can identify whether the image carried on the surface of the recording paper is an erasable image. The purpose of this is to promote the recycling of the recording paper by making it possible to determine that the image is erasable.

The identification unit is formed at the time of image formation using a color erasable developer with respect to the image carrying surface of the color erasable developer on the surface of the recording paper. It is provided for.
When provided on the front and back surfaces, it is desirable that the identification contents on each surface be different in order to prevent erroneous rewrite.

  By providing such an identification portion, the identification portion of the recording paper to be discharged can be visually confirmed, and the recording paper image-formed with a decolorable developer and the image with a non-decolorable developer. Separation is possible in the case where the formed recording paper is mixed. In this way, the separation can prevent the recording paper that can be recycled by decoloring from being inadvertently discarded. Furthermore, in the case of recording paper imaged on both front and back sides with a decolorable developer, the identification contents are changed as described above to shift to decoloring work on the back side after decoloring on one side. Can be made.

  On the other hand, in addition to visual observation, discrimination for sorting may be performed based on detection of the identification unit in the image forming apparatus, and the recording paper may be conveyed according to the sorting result.

  FIG. 15A shows a configuration for a case where an identification unit is provided on each of the front and back surfaces. In FIG. 15A, on the side where the recording paper is introduced into the erasing apparatus 200, Sensors 310 and 311 are provided for detecting identification portions on the front and back surfaces of the recording paper with the conveyance path interposed therebetween. Although not shown, each of the detection sensors 310 and 311 is connected to a control unit that sets the position of a member that switches the conveyance path of the recording paper discharged from the erasing apparatus 200.

  In such a configuration, the recording paper is transported to the erasing device 200 for erasing on one side, and if the back side can also be erased in the detection result, the recording paper is directed toward the reverse transport path. After transporting and turning over, a decoloring operation is performed on the back surface using a decoloring device. As described above, when the front and back surfaces are objects to be erased, the contents of the identification part on the front and back surfaces are merely changed, and the surface is not mistaken for single-sided erasing.

On the other hand, as a case where the same determination result as that of the presence / absence of the identification unit is obtained, the decolored state of the image can be set as a determination target.
If the image remains when it is introduced into the decoloring device and it can be determined that the image has been decolored and blank after the decoloring operation, the recording paper using a decolorable developer is used. If the image remains even after passing through the decoloring device, it can be determined that an image of a developer other than the decolorable developer remains. Thus, the recording paper using the erasable developer is used for recycling, and the recording paper using the developer that could not be erased is separated by being subjected to a transport form different from recycling. It will be.

  FIG. 15B shows the configuration used in this case. In FIG. 15B, detection sensors 320 and 321 such as a CCD camera are provided at the recording paper introduction position and discharge position with respect to the erasing apparatus 200. Yes.

  Similarly to the case shown in FIG. 15A, the detection sensors 320 and 321 are connected to a control unit 400 that sets the position of a switching member that switches the conveyance path of the recording paper discharged from the erasing apparatus 200. Yes.

  The control unit 400 sets a path F1 for conveying the decolored recording paper toward the inkjet head 253 and a path F2 for conveying the non-erased recording paper toward the paper discharge tray 252A. Yes.

  Based on the resolution result between the detection sensors 320 and 321, the decolored recording paper is conveyed toward the inkjet head 253 so that recording can be performed again, and the non-decolored recording paper Are conveyed toward the paper discharge tray 252A and sorted. By performing such separation, it is possible to prevent an accident in which recording is erroneously performed on already printed recording paper.

Next, still another embodiment of the present invention will be described.
A feature of this embodiment is that it enables decoloring of recording paper that is continuously conveyed.
FIG. 16 is a schematic diagram for explaining the above feature.
In FIG. 16, the erasing apparatus 500 includes a heating roller 501 and pressure rollers 502 and 502 ′ that are used as pressure means, facing each other across the conveyance path of the recording paper.

The pressure rollers 502 and 502 ′ as the pressure means are a pair of rollers arranged along the circumferential direction of the heating roller 501, and a link lever 503 that can swing with the fulcrum shafts 502A and 502A ′ as the base ends. , 503 are rotatably supported at the swinging end of
The link levers 503 and 503 ′ are configured such that the pressure rollers 502 and 502 ′ are moved to the heating roller 501 by pullable tension springs 505 and 505 ′ arranged between the swing end side and the shaft support portion of the heating roller 501. The contact state with the heating roller 501 by this behavior is changed by the cam profile of the eccentric cams 504 and 504 ′.

  The eccentric cams 504 and 504 ′ are provided for the link levers 503 and 503 ′, respectively, and the rotation phase (rotation amount) is controlled by a drive motor (not shown), and pressurization is performed according to the rotation phase. The rollers 502 and 502 ′ are controlled to press and separate from the heating roller 501 independently. In the figure, reference numeral 600 denotes a registration roller, and reference numerals 601 and 602 denote recording paper conveyance guides.

  As shown in FIGS. 17 and 18, the link levers 503 and 503 ′ can abut against the heating roller 501 alternately by setting independent rotational phases of the eccentric cams 504 and 504 ′. .

  In such a configuration, in a standby state before the recording paper is transported, as shown in FIG. 19, a state is set in which only the pressure roller 502 located on the downstream side in the recording paper transport direction contacts the heating roller 501. Has been. The heating roller 501 at this time does not generate heat from the heat source, but may generate heat for preliminary heating.

  On the other hand, when a recording sheet to be decolored on one side is conveyed, as shown in FIG. 20, the pressure roller 502 ′ that has been separated from the heating roller 501 during standby comes into contact with the heating roller.

  The timing at which the pressure roller 502 ′ abuts on the heating roller 501 is when the surface temperature of the heating roller 501 reaches a temperature at which the color can be erased. Further, the surface temperature of the pressure roller 502 ′ cannot be erased. It is said that the temperature has been reached.

  When the pressure roller 502 ′ contacts the heating roller 501 at such timing, the heating roller 501 that contacts one side of the recording paper can perform the decoloring operation by the decoloring temperature, and the pressure roller 502 ′ Since there is a temperature difference with respect to 501 and the temperature is also a temperature that cannot be erased, erasing can be performed only on one side of the recording paper. That is, the pressure roller 502 or 502 ′ is less affected by the heat from the heating roller 501 by being separated from the heating roller 501 until the recording paper erasing operation is started. There is no increase in temperature on the surface opposite to the one side, so that the decoloring operation for only one side of the recording paper can be performed reliably.

  The decoloring temperature and non-decolorable temperature in the above case are preferably set to 130 ° and 56 ° from the experimental results shown in FIGS. 13 and 14, respectively. Therefore, the temperature can be appropriately set.

  In the state shown in FIG. 20, after the erasing operation for one side of the recording paper conveyed is finished and the recording paper is discharged from the erasing apparatus 500, the erasing operation for one side is continuously performed. When the recording paper to be performed is conveyed, as shown in FIG. 21, the pressure roller 502 ′ that has been in contact with the heating roller 501 is separated, and instead the pressure roller 502 that has been separated until then is heated. It is brought into contact with the roller 501. The contact timing at this time is the same as in the case of single-side decolorization of the previous recording paper.

  In this way, when performing the decoloring operation on one side of the recording paper that is continuously conveyed, a pair of pressure rollers are alternately brought into contact with the heating roller, so that Unlike the case where one pressure roller is in contact with the heating roller, the cooling effect on the pressure roller side is enhanced. As a result, even when heat from the heating roller is transmitted to the opposite side of one side of the recording paper, the surface is maintained in an erasable state by the cooling action of the pressure roller. Therefore, it is possible to reliably perform the decoloring work for only one side of the.

FIG. 22 shows a flowchart for explaining the decoloring operation for one side of such a continuously conveyed recording sheet.
In FIG. 22, the erasing mode is determined (ST10), and when the erasing operation for one side is selected as a result, the rotation driving and heating of the heating roller 501 are started (ST11). The surface temperature 501 (shown as decolorable temperature in the figure) is monitored, and the surface temperature on the pressure roller side is monitored. The temperature to be monitored is the temperature that can be erased on the heating roller 501 side, and the temperature that is not erasable on the pressure roller side (indicated as non-erasable temperature in the figure) is the target (ST12, 13).

  When the temperature on the heating roller and pressure roller side reaches a predetermined temperature, the registration roller starts to be driven and the recording paper starts to be conveyed, and the pressure roller contacts the heating roller 501 (ST14). The state in this case is as described in FIG.

  The decoloring work for one side of the first recording sheet is monitored (ST15), and the progress state of the decoloring work for one side of all the recording sheets (shown as all pages in the figure) is monitored. If it is monitored (ST16) and the process has not been completed, the contact of the pressure roller is switched, and the decoloring operation for one side of the conveyed recording paper is repeated. The state in this case is as described in FIG.

  When the erasing operation for one side of all the recording papers is completed, the heating roller 501 stops heating, and the pressure rollers 502 and 502 'are returned to the standby state shown in FIG. 19 (ST17). If the decoloring work for one side of all the recording papers is not completed, as described above, the alternating contact switching of the pressure rollers completes the decoloring work for all the recording papers. Repeat until.

  In the above-described configuration, when performing a decoloring operation on one side of the recording paper continuously conveyed, the pressure roller is brought into contact with the heating roller alternately to thereby apply pressure. The transition to the non-erasable temperature on the roller side is accelerated. That is, by being away from the heating roller, it is difficult to be affected by the heat from the heating roller, so that the transition to the color erasable temperature is accelerated. As a result, it is possible to shorten the time until the next decoloring operation for one side of the recording paper.

Next, a configuration for improving the cooling function of the pair of pressure rollers described above will be described.
FIG. 23 shows a configuration in which a cooling roller 700 capable of contacting and separating a pair of pressure rollers 502 and 502 ′ is provided.
The cooling roller 700 is disposed at a position where the pressure roller 502 or 502 ′ separated from the heating roller 501 can come into contact with the cooling roller 700 so that the surface temperature of the contacted pressure roller can be set to an unerasable temperature. It has become.

  The cooling roller 700 is configured to be able to rotate in conjunction with the drive source of the heating roller 501, and thereby, the surface of the pressure roller that has come into contact can be cooled without deviation along the circumferential direction. ing.

  24 to 26, for the case where the cooling roller 700 is provided, the recording paper for performing the decoloring operation for one side is continuously conveyed from the standby state shown in FIGS. 19 to 21. It is a figure which shows the contact state of the pressure roller and cooling roller in a state.

On the other hand, in addition to the decoloring work for one side of the recording paper, a configuration using a pressure roller can be applied to the decoloring work for both sides.
In this case, a heater is built in a pair of pressure rollers, and both the heating roller and the pressure roller are brought into contact with each other when the temperature reaches a decolorable temperature, whereby the front and back surfaces of the recording paper to be conveyed are The target decoloring work can be performed. In this case, since the pressure roller does not have a cooling function by the heating roller, it is not necessary to switch the pressure roller to the heating roller for every recording sheet continuously conveyed.

  Further, an electrophotographic fixing device can be used as the erasing device described above. In this case, erasing is performed at a temperature lower than the fixing temperature set for the heating roller used in the fixing device. By using the toner that can be used, it is possible to have both the fixing function and the color erasing function only by controlling the temperature of the fixing roller, preventing an increase in the size of the apparatus and reducing the cost.

100, 200 Decoloring apparatus 101, 201, 501 Heating roller 102, 202, 502, 502 ′ Pressure roller 105 Gap detection means 106 Eccentric cam 108 Gap control means 700 Cooling roller S Recording paper

JP 2005-263895 A Japanese Patent No. 3286214 JP 2001-302954 A

Claims (14)

In an image forming apparatus capable of forming images on both front and back surfaces of a recording medium using a developer capable of reversible color development and decoloration,
A heating roller and a pressure unit facing each other across the conveyance path of the recording medium,
The pressurizing means is displaceable to a position where the recording medium can be nipped and conveyed facing the heating roller, and a position where the recording medium is not nipped and conveyed away from the heating roller. When the image carried on one side of the sheet is decolored, when the image is moved to a position where it can be nipped and conveyed, a gap corresponding to the thickness of the recording medium is provided so as to be opposed to the heating roller. An image forming apparatus. In an image forming apparatus capable of forming images on both front and back surfaces of a recording medium using a developer capable of reversible color development and decoloration,
A heating roller and a pressure unit facing each other across the conveyance path of the recording medium;
A gap detection means provided on the pressure means side for detecting a gap facing the pressure roller with respect to the heating roller;
A gap adjusting means provided on the pressure means side, wherein the pressure means is brought into contact with and separated from the heating roller between a holding conveyance position of the recording medium and a position where the holding conveyance is not performed;
A gap control unit provided on the pressure unit side, wherein a gap detection unit for detecting a facing gap of the pressure unit with respect to the heating roller is connected to the input side, and the gap adjustment unit is connected to the output side. And
The gap control unit corresponds to the thickness of the recording medium as a displacement amount for displacing the pressurizing unit to the nipping and conveying position of the recording medium when the image carried on one side of the recording medium is decolored. An image forming apparatus, wherein the gap adjusting means is driven and controlled to set a facing interval with a gap so as to face the heating roller.   The image forming apparatus according to claim 2, wherein a pressure roller is used as the pressure unit, and a heater is built in the pressure roller.   4. A heating roller and a pressure roller used in a fixing device equipped when an electrophotographic method is used as the heating roller and the pressure unit, respectively. Image forming apparatus. In an image forming apparatus capable of forming images on both front and back surfaces of a recording medium using a developer capable of reversible color development and decoloration,
An image forming apparatus, wherein members capable of selecting a heating function and a cooling function are arranged on both sides of the conveyance path of the recording medium.   The image forming apparatus according to claim 5, wherein the member capable of selecting the heating function and the cooling function includes a blower that supplies heated air or cooling air to the recording medium.   The recording medium conveyance path is provided with an electrophotographic image forming unit and a printing image forming unit, and the developer erasing unit is provided between the image forming units. The image forming apparatus according to claim 5, wherein:   The image forming apparatus according to claim 7, wherein a heating member provided in a fixing device is used as the member having a heating function in the electrophotographic image forming unit.   The image forming apparatus according to claim 7, wherein the electrophotographic image forming unit uses a member facing the heating member provided in the fixing device as a member having a cooling function.   The image forming apparatus according to claim 1, wherein the recording medium is provided with an identification unit for identifying that the color can be erased.   An identification unit provided on the recording medium for identifying that erasing is possible is detected by a detecting unit provided on a conveyance path of the recording medium and used for determining whether or not erasing control is possible. The image forming apparatus according to claim 10. In an image forming apparatus capable of forming images on both front and back surfaces of a recording medium using a developer capable of reversible color development and decoloration,
A heating roller and a pressure unit facing each other across the conveyance path of the recording medium,
The pressurizing unit is composed of a pair of rollers arranged in the circumferential direction on the heating roller, and is selectively and pressure-contacted and separated from the heating roller independently. .   The pressurizing / separating control can be independently performed with respect to a cooling member provided separately from the heating roller. Image forming apparatus.   The image forming apparatus according to claim 12, wherein a heater is built in the pair of pressure rollers.

Images