JPH07239576A - Electrophotographic device - Google Patents

Abstract

PURPOSE:To provide an electrophotographic device equipped with an image erasing device being a compact and inexpensive device and capable of saving space in an office by integrally assembling the image erasing device in a double- sided copying machine. CONSTITUTION:This device is equipped with the image erasing device 62 where a wetting means 43 wetting toner on the surface of carried paper 8 where an image has been already printed on one side or both sides, a toner peeling means 44 making the already printed paper 8 into recycled paper 45 where the image has been already erased by heating the paper 8 after wetting and peeling the toner adhering to the surface of the paper, and a drying means 46 drying the wetted recycled paper 45 after peeling the toner are installed in the reversal paths 34 and 36 of a paper reversing means 11 between a fixing means 10 and a reversed paper housing means 12. Then, the recycled paper 45 where the image has been already erased by the image erasing device 62 is ejected to the reversed paper housing means 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a double-sided electrophotographic apparatus having an image erasing device.

[0002]

2. Description of the Related Art FIG. 14 shows an example of a double-sided copying machine as an electrophotographic apparatus capable of double-sided printing. The apparatus body 1 includes a paper feed tray 3 as a print paper storage means for storing the print paper 2, and a print paper feed unit 4 as a print paper feed means for feeding the stored print paper 2.
A photoreceptor 5 as a latent image carrier, a latent image forming unit 6 as a latent image forming means for forming a latent image on the photoreceptor 5, and the formed latent image with toner. An image forming unit 7 as a visualizing means, a transfer unit 9 as a transferring means for transferring the visualized visible image on the photoconductor 5 to the printing paper 2 to obtain a printed paper 8. A fixing unit 10 as a fixing unit that heats and fixes the toner adhering to the printed sheet 8 and a sheet reversing unit 11 as a sheet reversing unit that reverses the printed sheet 8 having the toner printed and fixed on one surface. , A reversal sheet storage tray 12 as a reversal sheet accommodating means for accommodating the reversible printed sheet 8 and for printing on the non-printed side of the reversible and accommodated printed sheet 8 It is broadly classified the printed paper 8 in the paper re-feed unit 13 as a re-feeding means for Saikyu paper to the printing paper feeding unit 4.

In this case, the printing paper feeding unit 4 comprises a feeding roller 14, a pair of feeding rollers 16 arranged in a feeding path 15, a registration roller 17 and the like.
The latent image forming unit 6 includes a light source unit 1 that emits laser light.
8, a plurality of mirrors 19, a lens 20, and the like. The image forming unit 7 includes a developing device 21, a charger 22,
A static eliminator 23, a cleaning device 24 and the like are arranged around the photoconductor 5. Below the photoconductor 5, a transfer unit 9 (transfer charger), a separation unit 25 (separation charger), and a transport unit 26 are arranged.
The fixing unit 10 is provided on the downstream side of the transport unit 26.
Are arranged. The fixing unit 10 includes a heater 2
The fixing roller 27 and the pressure roller 28 having the built-in 7a are arranged in pressure contact with each other. A pair of paper discharge rollers 29 and a paper discharge path 3 are provided on the downstream side of the fixing unit 10.
0, a pair of paper discharge rollers 31 are sequentially arranged, and the apparatus main body 1
A paper discharge tray 32 is attached to the outer side surface of the.

Further, branch pawls 33a and 33b are provided on the outlet side of the paper ejection roller 29, and the printed paper 8 ejected from the paper ejection roller 29 by the branch pawl 33a is directed to the paper ejection path 30 side. It controls whether it is sent or sent to the side of the reversing path 34 of the paper reversing unit 11. Paper reversing unit 1
In addition to the reversing path 34, the reversing path 34 includes a reverse feeding roller 35 disposed in the reversing path 34, a reversing path 36 located below the reverse path 34 on the opposite side, and a conveying roller 37. The reversal sheet storage tray 12 is arranged on an extension of the reversal path 36. A refeed unit 13 including a refeed roller 38 and a refeed path 39 is arranged at one end of the reversal sheet storage tray 12.

As a result, the printing paper 2 fed from the paper feed tray 3 is copied on one side by the transfer unit 9 below the photoconductor 5 to become the printed paper 8, and the fixing unit 1
After being fixed at 0, it is guided to the upper reversing path 34 by the upward branch claw 33a. The printed sheet 8 that has been copied on one side is inverted from the inversion path 34,
Since the branch claw 33b keeps the path open, the branch claw 33b is guided to the lower reversing path 36, and the copied surface faces upward and is sent to the reversal sheet storage tray 12. And
The printed sheet 8 with the one-sided copy is fed by the sheet re-feeding roller 38, passes through the sheet re-feeding path 39, and is guided again from the transporting path 15 to the position of the photoconductor 5.
This time, the surface on the non-printed side is copied, so that the printed paper 8 is copied on both sides. afterwards,
After the double-sided-printed printed sheet 8 is fixed, the branch claw 33a faces downward and is discharged onto the discharge tray 32 via the discharge roller 31. The double-sided printing process can be performed by such a series of operations.

Further, in recent years, there has been an increasing demand for an image erasing apparatus that erases and reproduces a printed sheet (the printed sheet 8) inside the office without taking confidential documents and the like out of the office. An example of the image erasing device will be described with reference to FIG. The main body 40 of the apparatus has a printed paper feed tray 41 (hereinafter, referred to as the paper feed tray 4) as a printed paper storage means for storing the printed paper 8 with a part thereof protruding to the side surface of the main body.
1) and a printed paper feeding unit 42 (hereinafter referred to as a paper feeding unit 42) as a printed paper feeding means for feeding the printed paper 8 stored in the paper feeding tray 41. A wetting unit 43 as a wetting means for wetting the toner surface of the fed printed paper 8 and a toner removing means for heating the wet printed paper 8 to remove the toner adhering to the paper surface. The toner peeling unit 44 and the drying unit 46 as a drying unit that dries the wet printed paper 8 after the toner is peeled off to make the erased recycled paper 45.

In this case, in the paper feeding unit 42,
A paper feed roller 47 for feeding the printed paper 8 in the paper feed tray 41, a conveyance path 48, a conveyance roller 49, and the like are provided. In the wetting unit 43, the treatment liquid 5
0, a coating roller 51, a conveyance roller 52, etc. are provided. In the toner peeling unit 44, a pair of toner peeling rollers 54 each having a heater 53 built therein, a branching claw 55 that contacts these toner peeling rollers 54, and a cleaning roller 5.
6 and the like are provided. In the drying unit 46, a drying roller 58 having a heater 57 built therein, and the drying roller 5
A pressure roller 59 and the like that are in contact with 8 are provided. A discharge tray 60 for storing the erased recycled paper 45 formed by drying the printed paper 8 is provided outside the main body on the downstream side of the drying unit 46. As a result, the printed sheet 8 is first wetted in the wetting unit 43, and then the toner on the sheet surface is erased in the toner peeling unit 44. Further, the printed paper 8 whose toner has been erased and is in a wet state is dried in the drying unit 46, and is discharged onto the paper discharge tray 60 as erased recycled paper 45. The image erasing process can be performed by such a series of operations.

[0008]

In recent years, many OA devices such as facsimiles, personal computers, laser printers, etc. have become confined in offices in addition to the above-mentioned double-sided copying machine (see FIG. 14) capable of double-sided copying. It is the current situation that it is installed. At the same time, the demand for the image erasing device (see FIG. 15) as described above, which erases and reproduces confidential documents and general printed paper inside the office, is further increased from the viewpoint of resource conservation by maintaining confidentiality and recycling. Cage,
In the future, it will be an essential item in the office. However, if such an image erasing device is to be provided in an office, it must be installed side by side with another OA device such as a copying machine or a printer, and a space for installing the image erasing device is newly required. Become. As described above, at this stage, the electrophotographic apparatus such as a double-sided copying machine and the image erasing apparatus have to be separately installed, so that there is a problem that the office space becomes small. It is not economical to install them separately.

[0009]

According to a first aspect of the present invention, there is provided a print sheet storing means for storing print sheets which can be printed on both sides, and a print sheet feeding means for feeding the stored print sheets. A latent image carrier, latent image forming means for forming a latent image on the latent image carrier, visualization means for developing the formed latent image with toner, and the visualized image forming means. Transferring means for transferring the visible image on the latent image carrier to the printing paper to form a printed paper, fixing means for heating and fixing the toner adhering to the printed paper, and the toner is printed and fixed on one side. A sheet reversing means for reversing the printed sheet, a reversal sheet storing means for storing the reversed printed sheet, and a print on the non-printed side of the reversed stored sheet In order to carry out In an electrophotographic apparatus provided with a sheet re-feeding unit for re-feeding the sheet, a single-sided sheet that has been conveyed in a reversing path of the sheet reversing unit between the fixing unit and the reversing sheet storing unit. Wetting means for wetting the toner on the surface of the printed paper with both sides printed, and toner removing means for heating the wet printed paper to remove the toner adhering to the surface of the paper to obtain erased recycled paper. And an image erasing device provided with a drying means for drying the wet erased recycled paper after the toner has been peeled off, and the erased recycled paper whose image has been erased by the image eraser is inverted. The paper is stored in the paper storage means.

According to a second aspect of the present invention, in the first aspect of the present invention, at least one of the wetting means and the toner peeling means performs a wetting or peeling operation on the printed paper conveyed during double-sided image formation. A double-sided image forming operation stop control means for stopping is provided.

According to a third aspect of the present invention, in the first aspect of the present invention, there is provided double-sided image forming operation stop control means for stopping the wetting operation of the wetting means on the printed sheet conveyed during double-sided image formation. At least one of the wetting means, the toner peeling means, and the drying means is formed by a pair of rollers capable of normal rotation and reverse rotation, and the position of the printed sheet being conveyed is detected before the pair of rollers. Reversing operation start control for reversing the pair of rollers to reverse the pair of rollers after detecting the trailing edge of the printed sheet by the sheet position detecting section when reversing the sheet. Means were provided.

According to a fourth aspect of the present invention, in the first, second or third aspect of the present invention, erased recycled paper detecting means for detecting whether or not erased recycled paper is stored in the reversal paper storage means is provided. If the erased recycled paper detecting means detects that the erased recycled paper is stored in the reverse sheet storage means during double-sided image formation, the stored erased recycled paper is discharged to the outside of the main body. A double-sided printing operation control means for causing the paper to perform double-sided printing operation after discharging the paper is provided.

According to a fifth aspect of the present invention, in the first, second or third aspect of the present invention, there is provided recycled paper size detection means for detecting the recycled paper size of the erased recycled paper stored in the reversal paper storage means, When the double-sided image is formed, the recycled paper size detected by the recycled paper size detecting means is compared with the printing paper size of the printing paper to be printed detected by the printing paper size detecting means, and this printing paper size is reproduced. There is provided double-sided printing operation control means for performing double-sided printing operation using the erased recycled paper stored in the reversal paper storage means when the paper size is equal to or larger than the paper size.

[0014]

According to the first aspect of the present invention, the image erasing device is incorporated and integrated in the reversing path in the double-sided copying machine which is an electrophotographic device, so that the double-sided printing function and the image erasing function are integrated into one device. Therefore, it is possible to obtain a low-cost and downsized composite device. Moreover,
In this case, since the erased recycled paper is discharged into the reversal paper storage means for double-sided printed paper, the erased recycled paper stored in the reversal paper storage means is used by the re-feeding means. By feeding the paper, the user does not need to reset the erased recycled paper separately.
As a result, the double-sided printing operation can be performed immediately using the erased recycled paper, and the operability can be improved. Further, from the above, it is not necessary to separately install the electrophotographic apparatus and the image erasing apparatus in the office as in the conventional case, and it is possible to reduce the space in the office.

According to the second aspect of the present invention, when the double-sided image is formed, the wetting or peeling operation is stopped using the double-sided image forming operation stop control means. To make the
It is possible to prevent the image formed at the time of forming the double-sided image from being accidentally erased.

According to the third aspect of the invention, when the double-sided image is formed, the wetting operation is stopped by the double-sided image forming operation stop control means, and at the time of reversing the paper, the paper position detecting means detects the printed paper. By detecting the trailing edge, the pair of rollers is reversed by the reversing operation start control means to start the reversing operation on the printed paper, so the path length of the reversing path for reversing the paper is determined. It is possible to shorten the length, and thereby the time required for the reversing operation can be shortened.

According to the present invention, when the erased recycled paper detecting means detects that the erased recycled paper remains in the reversal paper storage means during double-sided image formation, the double-sided printing operation control means is provided. Since the stored erased recycled paper is ejected to the outside of the main body and the double-sided printing operation is performed, the printed paper for double-sided printing and the erased recycled paper are the same reversal paper. It is no longer mixed in the storage means,
The problems such as skew and paper jam can be eliminated, and the double-sided printing operation can be performed smoothly.

In the fifth aspect of the invention, when the double-sided image is formed, the double-sided printing operation control means is used to detect the recycled paper size detected by the recycled paper size detecting means and the printing detected by the printing paper size detecting means. Compare the print paper size of the print paper you are going to perform, and when this print paper size is equal to or larger than the recycled paper size, perform the double-sided printing operation using the erased recycled paper that remains in the reverse paper storage means. Since it is performed, the double-sided printing operation can be performed immediately without the need to separately set the erased recycled paper, and the operability can be further improved.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the invention described in claim 1 is shown in FIGS.
It will be described based on. In addition, the related art (FIGS. 14 and 15)
The description of the same parts as those of the reference) will be omitted, and the same reference numerals will be used for the same parts. An example in which a double-sided copying machine (see FIG. 14) is used as an electrophotographic apparatus and an image erasing device (see FIG. 15) is integrally incorporated in the double-sided copying machine is divided into the following first to third embodiments. This will be explained sequentially. The description of the double-sided copying machine will be omitted, and only the image erasing device will be described. First, a first embodiment will be described with reference to FIG. A sheet reversing unit 11 as a sheet reversing unit is arranged in the apparatus main body 1, and the processing liquid 50 is provided in a reversing path 34 above the sheet reversing unit 11.
A wetting unit 43 as a wetting means, a toner peeling roller 54 having a heater (not shown) built in, and a backup roller 5 in contact with this roller.
The image erasing device 62 is provided with a toner peeling unit 44 as a toner peeling unit composed of 4a and a scraper 61, and a drying unit 46 as a drying unit consisting of a pair of drying rollers 58 having a heater (not shown) built therein. It is arranged. In addition, here, the erased recycled paper 45 whose image has been erased by the image erasing device 62 disposed in the inversion path 34 is stored as a reversal paper as a reversal paper storage means provided in the lower portion of the apparatus main body 1. The sheet is discharged to the tray 12 (also referred to as an intermediate tray).

The operation of erasing an image in such a configuration will be described. First, the printed paper 8 (one-side copied paper or two-sided copied paper) from which an image is to be erased is set in one of the upper and lower three paper feed trays 3 (here, the second tray). . Then, when the paper feed tray 3 in which the printed paper 8 to be erased is set is selected and an image erasing start command is executed, the printed paper 8 follows the same path as that of the normal printed paper 2. However, each process of transfer and fixing is not carried out, and is conveyed to the position of the paper discharge roller 29. In this case, when the cleaning blade 24a is in contact with the photosensitive member 5 without any toner, the friction coefficient between the cleaning blade 24a and the photosensitive member 5 increases,
The drive torque of the photoconductor 5 increases. Therefore, as a means for avoiding such a phenomenon, there is a method of releasing the cleaning blade 24a at the time of erasing an image, or developing a small amount of toner on the photoconductor 5 for one second every 10 seconds. is there. In the method using this toner, the toner hardly moves from the photoconductor 5 side to the paper side unless the transfer unit 9 is operated, and the surface contacting the photoconductor 5 is the paper surface on which the image is erased in the subsequent stage. Therefore, even if a small amount of toner remains on the paper, the toner can be separated from the paper without any problem. Further, the printed paper 8 for image erasing is guided to the fixing unit 10. At this time, if the toner attached to the paper is heated and pressed, the binding force between the toner and the paper is increased, and the image erasing is performed. It becomes difficult. For this reason, when erasing the image, the heater in the fixing unit 10 is not heated, or a temperature sensor (not shown) is used, and the temperature is sufficiently low (for example, 50 ° C. or less). ) Is controlled so that the image erasing work is performed only in ().

Then, the printed sheet 8 guided to the position of the sheet discharge roller 29 is guided to the upper reverse path 3 by the branch claw 33a.
Guided to 4. The image erasing device 62 in the reversing path 34
In the above, the printed paper 8 is coated with the treatment liquid 50 by the application roller 51, the toner is peeled off by the toner peeling roller 54 to become the erased recycled paper 45, and further, the erased recycled paper 45 in the wet state. Are dried by the drying roller 58. The erased recycled paper 45, on which the image has been erased and dried in this manner, is fed back by the feed roller 35 and guided from the reversing path 34 to the reversing path 36 that is continuously provided below the reversing path 34 to store the reversal paper. Tray 1
2 will be discharged and stored.

Further, the series of steps described so far is the processing for erasing the image of the printed sheet 8 having one side copied, but in the case of erasing the image of the printed sheet 8 having both sides copied. In addition, the following process is added. That is, in the state in which the erased recycled paper 45 whose one side has been erased is stored in the reversal sheet storage tray 12, the erased surface P on which the image has been erased faces upward, and the unerased surface Q on which the image has not been erased It is said to be downward. In such a state, the erased recycled paper 45 whose one side has been erased is fed by the refeed roller 38 and guided again into the transport path 15 via the refeed path 39. After that, the same route as in the case of the one-sided erasing described above is followed, the image is erased by the image erasing device 62 in the reversing route 34, the image is fed back, and the sheet is discharged again via the reversing route 36. As a result, it is possible to store the erased recycled paper 45 with the images erased on both sides in the reverse paper storage tray 12. In this case, the erased recycled paper 45 after the one-sided erasing is fed from the re-feeding path 39 and passes through the position below the photoconductor 5 again. The direct contact is on the unerased surface Q side of the printed paper 8, and the erased surface P side on which the image has already been erased is turned over and does not contact the photoconductor 5. Therefore, the above-mentioned problem of the cleaning blade 24a is concerned. The toner does not adhere to the erasing surface P side, and the image erasing process can be performed smoothly.

Next, a second embodiment will be described with reference to FIG. Here, the image erasing device 62 is connected to the lower reverse path 3
It is arranged in 6. With such a configuration, the printed sheet 8 is guided to the upper reversing path 34 by the branching claw 33a and inverted, and is reversely fed by the reverse feeding roller 35 to be the image erasing device 62 of the lower reversing path 36. To reach. Then, the image erasing device 62 erases and dries the image and discharges it as the erased recycled paper 45 into the reversal paper storage tray 12. As described above, in this embodiment, since the reverse feeding roller 35 can be arranged at the position closer to the branch claw 33a, the length of the upper reverse path 34 is longer than that in the first embodiment (see FIG. 1) described above. Can be shortened, and thereby the time spent for reversal can be shortened, so that the number of erased sheets per unit time can be increased.

Also, the printed paper 8 with both sides copied
In the case where both sides of the sheet are to be erased, the erased surface P of the erased recycled paper 45 at the stage of the one-sided erase is facing downward in the reverse sheet storage tray 12, and the sheet is re-fed from the sheet re-feeding path 39. When it reaches the photoconductor 5, the erasing surface P faces upward and comes into direct contact with the photoconductor 5, so there is a concern that toner relating to the problem of the cleaning blade 24a as described above may adhere to the erasing surface. Therefore, the photoconductor 5
When a method of developing a small amount of toner is selected, the transfer timing of the double-side printed sheet 8a to the position of the photoconductor 5 is controlled by the registration roller 17 so that the toner adheres to the erasing surface side as much as possible. Try not to do it.

Next, a third embodiment will be described with reference to FIG. In both of the above-described two embodiments (see FIG. 1 and FIG. 2), the same paper feed tray 3 is used to perform printing on one side or both sides of the printing paper 2 and for erasing the image on one side or both sides. Although the printed sheet 8 for printing is fed, in the present embodiment, the printing tray and the image erasing tray are configured as separate trays. That is, here, the paper feed tray 63 dedicated to the image erasing paper is provided on the side surface of the apparatus main body 1 above the paper discharge tray 32.
Printed paper 8 for image erasing is accommodated in the paper feed tray 63. The image erasing device 62 is arranged in the reversing path 36 as in the second embodiment. With such a configuration, in the case of erasing the image on one side, the printed sheet 8 does not pass through the positions of the photoconductor 5 and the fixing unit 10, so that the conveyance timing as described in the second embodiment is used. The control of is unnecessary. Further, in this case, the fixing unit 10 may remain at a high temperature,
Even if the copy command is executed immediately after the image is erased, the operation can be performed immediately and the work efficiency can be improved.

As described above, by incorporating and integrating the image erasing device in the double-sided copying machine, it is possible to combine the double-sided printing function and the image erasing function in one device, which is low cost and compact. A composite device can be obtained.
As a result, it is not necessary to separately install the electrophotographic apparatus and the image erasing apparatus in the office as in the conventional case, so that the space in the office can be reduced. Further, in this case, since the erased recycled paper 45 is discharged into the reversal paper storage tray 12 for the printed paper 8 whose both sides are copied, the erased recycle paper 45 stored in the reversal paper storage tray 12 is erased. By feeding the recycled paper 45 using the re-feeding unit 13, the user does not need to separately reset the erased recycled paper 45, and the double-sided printing operation can be performed immediately using the erased recycled paper 45. As a result, the operability can be improved. Further, the paper feed tray 3 in this embodiment is not only a tray for double-sided copying but also a tray for image erasing, so that a new paper feeding mechanism dedicated to image erasing is unnecessary, and a compact structure is achieved. can do.

Next, an embodiment of the invention described in claim 2 will be described with reference to FIGS. The description of the same parts as those of the invention according to claim 1 (see FIGS. 1 to 3) will be omitted, and the same reference numerals will be used for the same parts. In this embodiment, in the electrophotographic apparatus according to the first aspect of the present invention, at least one of the wetting unit 43 and the toner stripping unit 44 wets or strips the printed sheet 8 conveyed during double-sided image formation. A double-sided image forming operation stop control means 64 for stopping the operation of the above is provided. Hereinafter, a specific example of the double-sided image forming operation stop control means 64 will be described.

First, the first embodiment will be described with reference to FIG. As shown in FIG. 4A, the backup roller 5
The coating roller 51 and the treatment liquid 50 which are in contact with the la, the toner peeling roller 54 having a heater 53 built-in, and the lower drying roller 58 having a heater 57 built-in are housed in an image erasing case 65. A lever 66 is in contact with the bottom surface of the image erasing case 65, the lever 66 is housed in the case 66a, and an eccentric cam 67 is in contact with the bottom surface of the case 66a. In this case, an image erasing case 65 accommodating various rollers, a lever 66 accommodated in a case 66 a, and an eccentric cam 67.
Constitutes the operation stop control means 64 at the time of double-sided image formation.

The operation of the double-sided image forming operation stop control means 64 in such a configuration will be described. The lever 6 housed in the case 66a by the rotation of the eccentric cam 67.
6 can move the image erasing case 65 in the vertical direction. FIG. 4A shows a state where the image erasing case 65 is lifted up by the rotation of the eccentric cam 67. At this time, the application roller 51 is the backup roller 51a,
The toner peeling roller 54 is the backup roller 54a,
The lower drying roller 58 is in a state of pressing the upper drying roller 58. When the rollers are in contact with each other in this way, the image erasing operation can be performed. On the other hand, FIG. 4B shows a state in which the image erasing case 65 is lowered by the rotation of the eccentric cam 67. At this time, the coating roller 51 is the backup roller 5
From 1a, the toner peeling roller 54 is separated from the backup roller 54a, and the lower drying roller 58 is separated from the upper drying roller 58. In such a state where the rollers are separated from each other, the image erasing operation cannot be performed, and the printed sheet 8 that has been conveyed into the reversing path 34.
Passes through the position of the image erasing case 65 as it is, reaches the position of the reverse rotation roller 35, and is fed back. In the state of being lowered below, the normal operation of double-sided image formation can be performed. Therefore, in this way, the image erasing case 6
By moving 5 up and down, it is possible to eliminate the phenomenon that an image formed during double-sided image formation is accidentally erased.

Next, a second embodiment will be described with reference to FIG. The wetting unit 43 as a wetting unit is composed of an injection device (hereinafter, the injection device 43). Further, the backup roller 54a is in contact with the toner peeling roller 54,
A pressure roller 59 is in contact with the drying roller 58. In this case, the double-sided image formation operation stop control means 64 can be realized by controlling the ejection amount of the processing liquid 50 ejected from the ejection device 43. That is, during the double-sided image formation, the processing liquid 50 is prevented from being jetted from the jetting device 43, and the heater 53 of the toner peeling roller 54 and the heater 57 of the drying roller 58 are controlled not to be energized. On the other hand, when the image is erased, the ejection device 43
The processing liquid 50 is ejected from the above to perform a normal image processing step. Therefore, by performing ejection control of the ejection device 43 in this manner, it is possible to eliminate a phenomenon in which an image formed during double-sided image formation is erroneously erased.

Next, a third embodiment will be described with reference to FIG. Shaft of coating roller 51 and backup roller 51a
A spring 68 is hung between the shaft and the shaft, and they are in pressure contact with each other. A solenoid 69 is attached to the shaft of the coating roller 51. in this case,
The double-sided image forming operation stop control means 64 includes the solenoid 6
It can be realized by controlling the driving of the switch 9.
That is, the solenoid 69 is turned on during double-sided image formation.
The application roller 51 and the backup roller 51.
Separated from a. As a result, even if the printed paper 8 is conveyed, the treatment liquid 50 is not applied and the normal operation can be performed. At this time, the heater 53 of the toner peeling roller 54 and the heater 57 of the drying roller 58 are not energized. On the other hand, at the time of erasing the image, the solenoid 69 is turned off and the application roller 5
1 is brought into contact with the backup roller 51a. As a result, the processing liquid 50 can be applied to the surface of the printed paper 8 to perform a normal image erasing process. Therefore, by controlling the drive of the solenoid 69 in this manner, it is possible to eliminate a phenomenon in which an image formed during double-sided image formation is erroneously erased.

As described above, when the double-sided image is formed, the wetting or peeling operation is stopped by using the double-sided image forming operation stop control means 64 (the eccentric cam 67, the injection device 43, the solenoid 69). In addition, the image erasing device 62 can be set so as not to act on the printed paper 8, and thus it is possible to prevent erroneous erasing of the image formed when the double-sided image is formed. Further, the ejection control mechanism using the ejection device 43 of FIG. 5 and FIG.
Since the drive mechanism using the solenoid 69 of FIG. 4 can make the moving part smaller than the moving mechanism using the image erasing case 65 that moves up and down by the rotation of the eccentric cam 67 of FIG. Can be achieved.

Next, an embodiment of the invention described in claim 3 will be described with reference to FIGS. The description of the same parts as those in the first and second aspects of the present invention is omitted, and the same parts are designated by the same reference numerals. In the double-sided copying machine having the image erasing device 62 as described above,
When a double-sided image is to be formed, the printed sheet 8 is guided into the reversing path 34 (after passing through the image erasing device 62, if there is this image erasing device 62 in the reversing path 34), and is fed by the reverse feed roller 35. The reverse operation is started by the reverse feeding. However, in such a method, the path length of the reversing path 34 at the time of reversing becomes long and the time required for the reversing operation becomes long, and as a result, the number of double-sided image formation per predetermined time (for example, 1 minute) decreases. , Production efficiency will be poor.

Therefore, in this embodiment, the above-mentioned claim 1 is used.
In the electrophotographic apparatus of the invention described above, a double-sided image forming operation stop control means 70 for stopping the wetting operation of the wetting unit 43 on the printed sheet 8 conveyed at the time of double-sided image formation is provided. At least one of the toner peeling unit 44 and the drying unit 46 is formed by a pair of rollers capable of normal rotation / reverse rotation, and paper position detection is performed to detect the position of the printed paper 8 being conveyed before the pair of rollers. A photo sensor 71 as a means is provided,
A reversing operation start control means 72 for reversing the pair of rollers to start the reversing operation of the printed paper 8 after the rear end of the printed paper 8 is detected by the photo sensor 71 at the time of reversing the paper is provided. Hereinafter, a specific example will be described.

First, the first embodiment will be described with reference to FIG. Shaft of coating roller 51 and backup roller 51a
A spring 68 is hung between the shaft of the coating roller 51 and the shaft of the coating roller 51, and a solenoid 69 is mounted on the shaft of the coating roller 51. In this case, the operation stop control means 70 for double-sided image formation
Can be realized by controlling ON / OFF of the solenoid 69. In addition, the toner peeling unit 44
The toner peeling roller 54 that constitutes
Direction) and reverse rotation (direction) are possible. The scraper 61 that contacts the toner peeling roller 54 is biased by a spring 73, and one end of the scraper 61 is connected to a solenoid 74. A photo sensor 71 is arranged in front of the toner peeling roller 54. In this case, the reversing operation start control means 72 can be realized by controlling the toner peeling roller 54 in the normal rotation / reverse rotation based on the signal detected by the photo sensor 71.

In such a structure, the solenoid 69 is turned on to separate the coating roller 51 from the backup roller 51a during double-sided image formation. The printed sheet 8 conveyed by this is separated by the toner peeling roller 54.
Then, the toner peeling roller 54 is rotated in the reverse direction by detecting the rear end of the printed sheet 8 by the photo sensor 71. At the time of this reverse rotation, if the scraper 61 remains in contact with the toner peeling roller 54, it will be caught in the roller, so the solenoid 74 is turned on so that the scraper 61 escapes from the roller surface. By reversing the toner peeling roller 54 in this manner, the printed sheet 8 can be conveyed in the reverse direction and the reversing operation can be started. Therefore, in this way, the toner peeling roller 54 is normally rotated and
By adding the mechanism capable of reversing, it is not necessary to provide the reverse feeding roller 35 as shown in FIG. 4 described above, so that the path length of the reversing path 34 can be shortened and the structure can be made more compact. it can.

Next, a second embodiment will be described with reference to FIG. The coating roller 51, the processing liquid 50, and the toner peeling roller 54 are housed in an image erasing case 65. The image erasing case 65 has a mechanism that can be moved in the vertical direction similarly to the configuration of FIG. 4 described above. Further, here, the lower drying roller 58 can be rotated normally and reversely. The photo sensor 71 is located between the toner peeling roller 54 and the drying roller 58. In this case, the reversal operation start control means 72 is based on the signal detected by the photo sensor 71 and the drying roller 58.
Can be realized by controlling the normal rotation and the reverse rotation.

In such a structure, at the time of double-sided image formation, the image erasing case 65 is moved downward to separate the coating roller 51 and the toner peeling roller 54 from the backup rollers 51a and 54a. The printed paper 8 thus conveyed advances as the drying roller 58 rotates in the normal direction, and thereafter, the printed paper 8 moves.
When the rear end of the drying roller 58 is detected by the photo sensor 71, the drying roller 58 operates in the reverse direction. By reversing the drying roller 58 in this manner, the printed sheet 8 can be conveyed in the opposite direction and the reversing operation can be started. Therefore, by adding the mechanism capable of normal rotation / reverse rotation to the drying roller 58 in this way, it is not necessary to provide the reverse feeding roller 35 as shown in FIG. 4, and the path length of the reverse path 34 is shortened. A compact structure. Further, here, since the mechanism for letting the scraper 61 escape from the roller surface as shown in FIG. 7 is not required, the number of parts can be reduced and the cost can be reduced.

Next, a third embodiment will be described with reference to FIG. In general, some electrophotographic devices such as copying machines, printers, and facsimiles are provided with only the reversing unit A so that the pages are aligned in the order in which the printed sheets discharged onto the discharge tray are printed. FIG. 9 shows an example of a copying machine provided with only the reversing section A. Here, the reversing path 36 as shown in FIG. 1 does not exist in the lower part of the main body, but the reversing path 34 forming the reversing part A in the upper part of the main body. Is provided. In addition to the branch claw 33c, a branch claw 33b is newly provided near the entrance of the inversion path 34.

In this embodiment, in such a device,
An image erasing device 62 is provided in the inversion path 34, and
A mechanism for feeding the printed paper 8 backward by the drying roller 58 capable of normal rotation / reverse rotation as shown in FIG. 8 (second embodiment) is added. As a result, similarly to the second embodiment, it is not necessary to provide the reverse feeding roller 35 in the reversing path 34, so that the path length of the reversing path 34 can be shortened and the structure can be made compact.

As described above, at the time of double-sided image formation, the wetting operation is stopped by using the double-sided image formation operation stop control means 70, and at the time of reversing the sheet, the rear end of the printed sheet 8 is printed by the photosensor 71. When the reversal operation start control unit 72 detects the reverse rotation, the rollers (toner peeling roller 54, drying roller 58) are reversed to print the printed paper 8
Since the reversing operation is started at 1, the path length of the reversing path 34 for reversing the sheet can be shortened, and thus the time required for the reversing operation can be shortened. Further, in this case, since the number of double-sided image formation per predetermined time (for example, one minute) during double-sided image formation can be increased, the production efficiency can be improved.

Next, an embodiment of the invention described in claim 4 will be described with reference to FIGS. 10 and 11. In addition, claim 1
The description of the same parts as those in the invention described in 3 is omitted, and the same reference numerals are used for the same parts. In the double-sided copying machine having the image erasing device 62 described above,
When the erased recycled paper 45 is stored on the reverse paper storage tray 12 that stores both the printed paper 8 on which both sides have been printed and the erased recycled paper 45 on which the image has been erased, a double-sided image print command is issued. When executed, the printed paper 8 with double-sided printing is placed on the erased recycled paper 45 stored therein. In such a state where both sheets are mixed, it is not possible to sufficiently align them with a jogger (not shown) due to a difference in sheet size and the like, so that skew and sheet jam easily occur.

Therefore, in this embodiment, in the electrophotographic apparatus according to claim 1, 2 or 3, the reversal sheet storage tray 1 is used.
2 is provided with a transmissive sheet detection sensor 74 as an erased regenerated sheet detection means for detecting the presence or absence of a sheet of whether or not the erased regenerated sheet 45 is stored, and is inverted by the transmissive sheet detection sensor 74 during double-sided image formation. Paper storage tray 12
When it is detected that the erased recycled paper 45 is stored inside, the stored erased recycled paper 45 is discharged to the outside of the main body, and double-sided printing operation is performed after this discharging. Means 75 are provided. In FIG. 10, the transmissive paper detection sensor 74 is arranged above and below the reversal paper storage tray 12. Further, here, an erased recycled paper exclusive discharge tray 76 for storing the erased recycled paper 45 discharged to the outside of the main body.
(Hereinafter, referred to as an erased discharge tray) is the paper feed tray 3
Is provided below. Further, a branch claw 77 for guiding the erased recycled paper 45 to the erased paper discharge tray 76 is provided in the re-feeding path 39. The switching operation of the direction of the branch claw 77 is performed by using the double-sided printing operation control means 75.

The operation of the double-sided printing operation control means 75 having such a structure will be described with reference to the flowchart of FIG. Now, assume that the double-sided copy key is pressed and the double-sided image printing command is executed. Transmissive paper detection sensor 7
4 is turned on to check whether or not the erased recycled paper 45 is on the reverse paper storage tray 12, and when it is detected that it is not on the reverse paper storage tray 12, the branch claw 77
To the upper side, the transmissive paper detection sensor 74 is turned off, and the double-sided printing operation is performed as it is. On the other hand, when it is detected that the erased recycled paper 45 remains on the reversal paper storage tray 12, the branch pawl 77 is directed downward and the re-feed roller 38 is driven to exist on the reversal paper storage tray 12. The feeding of the erased recycled paper 45 is started and is discharged to the erased paper discharge tray 76 side. Then, after all the erased recycled paper 45 on the reversal paper storage tray 12 is discharged, the branching claw 77 is directed upward, and the transmissive paper detection sensor 7 is placed.
4 is turned off and double-sided printing operation is performed.

As described above, when it is detected that the erased recycled paper 45 remains in the reversal paper storage tray 12 during double-sided image formation, the erased recycled paper 45 stored therein is discharged to the outside of the main body. Since the double-sided printing operation is performed after the paper is printed, the printed paper 8 and the erased recycled paper 45 are not mixed in the same tray, that is, the reversal paper storage tray 12, and thus, Eliminate problems such as skew and paper jams,
The double-sided printing operation can be performed smoothly.

Next, an embodiment of the invention described in claim 5 will be described with reference to FIGS. 12 and 13. In addition, claim 1
The description of the same parts as those of the invention described in 4 is omitted, and the same parts are denoted by the same reference numerals. In the invention described in claim 4 described above, in order to eliminate problems such as skew and paper jam at the time of double-sided image formation, the erased recycled paper 45 remaining in the reversal paper storage tray 12 is once discharged to the outside of the machine. However, in such a method, the discharged recycled recycled paper 45 has to be set again, resulting in poor work efficiency.

Therefore, in this embodiment, in the electrophotographic apparatus according to claim 1, 2 or 3, the reversal paper storage tray 1 is used.
2 is provided with a paper size detection sensor 78 as a reproduction paper size detection means for detecting the reproduction paper size of the erased reproduction paper 45, and the reproduction paper size detected by the paper size detection sensor 78 during double-sided image formation. Is compared with the printing paper size of the printing paper 2 to be printed, which is detected by a known printing paper size detecting sensor (not shown) as a printing paper size detecting means, and this printing paper size is equal to the recycled paper size. Alternatively, a double-sided printing operation control means 79 for performing double-sided printing operation using the erased recycled paper 45 stored in the reversal paper storage tray 12 when the size is large is provided. In FIG. 12, a plurality of paper size detection sensors 78 are arranged on the reverse paper storage tray 12 at regular intervals.

The operation of the double-sided printing operation control means 79 having such a structure will be described with reference to the flowchart of FIG. Now, assume that the double-sided copy key is pressed and the double-sided image printing command is executed. Paper size detection sensor 7
8 is turned on, and it is first checked whether or not the erased recycled paper 45 is on the reverse paper storage tray 12. When it is detected that the sheet is not on the reverse sheet storage tray 12, the branch claw 77 is directed upward and the sheet size detection sensor 78 is turned on.
FF is set and double-sided printing operation is performed. On the other hand, when it is detected that the erased recycled paper 45 remains on the reverse sheet storage tray 12, the recycled paper size (TS) of the erased recycled paper 45 is detected by the paper size detection sensor 78 to print. The print paper size (CS) of the print paper 2 to be detected is detected by the print paper size detection sensor, and these recycled paper size and print paper size are compared. When the print paper size to be printed is equal to or larger than the recycled paper size (TS ≦ CS), the branch claw 77 is directed upward and the paper size detection sensor 78 is turned off.
The erased recycled paper 45 on the reverse paper storage tray 12 is fed to perform double-sided printing operation. On the contrary, when the recycled paper size on the reverse paper storage tray 12 is larger, the branching claw 77 is directed downward, the re-feeding roller 38 is operated, and the erased recycled paper 45 is discharged. Tray 76
The sheet is discharged upward, and then the branch claw 77 is directed upward, the sheet size detection sensor 78 is turned off, and the double-sided printing operation is performed.

As described above, during double-sided image formation, the recycled paper size of the erased recycled paper 45 on the reversal paper storage tray 12 detected by the paper size detection sensor 78 and the printing detected by the print paper size detection sensor. The print paper size of the print paper 2 to be printed is compared, and when the print paper size is equal to or larger than the recycled paper size, the erased recycled paper 45 remaining in the reversal paper storage tray 12 is used. Since the double-sided printing operation is performed, it is not necessary to separately set the erased recycled paper 45 separately, and thus the double-sided printing operation can be performed immediately and the operability can be further improved. .

[0050]

According to the first aspect of the present invention, there is provided a print sheet storing means for storing print sheets which can be printed on both sides, a print sheet feeding means for feeding the stored print sheets, and a latent image carrier. A latent image forming means for forming a latent image on the latent image carrier, a visualization means for developing the formed latent image with toner, and the visualized latent image carrier. Transfer means for transferring the above-mentioned visible image onto the printing paper to form a printed paper, fixing means for heating and fixing the toner adhering to the printed paper, and the printed paper with toner fixed on one side. Paper reversing means for reversing the paper, reversing paper storing means for storing the reversed printed paper, and printing on the non-printed side of the reversed and stored printed paper The printed paper is fed to the printing paper feeding means. In an electrophotographic apparatus provided with a sheet re-feeding unit, the transported one side or both sides are printed in a reversing path of the sheet reversing unit between the fixing unit and the reversing sheet storing unit. Wetting means for wetting the toner on the surface of the printed paper, and toner peeling means for heating the printed paper after wetting to remove the toner adhering to the surface of the paper to make erased recycled paper, and the toner peeling An image erasing device provided with a drying means for drying the wetted erased recycled paper after being crushed, and discharging the erased recycled paper from which an image has been erased by the image erasing device to the reversal paper storage means. I did so,
By thus incorporating and integrating the image erasing device in the reversing path in the double-sided copying machine, it is possible to combine the double-sided printing function and the image erasing function in a single device, which is a low-cost and compact composite. The device can be obtained. Further, this eliminates the need to separately install the electrophotographic apparatus and the image erasing apparatus in the office as in the conventional case, so that the space in the office can be further reduced. In addition, the erased recycled paper is ejected into the reverse paper storage means for printed paper.
By feeding the erased recycled paper stored in the reversal paper storage means using the re-feeding means, it is not necessary for the user to separately reset the erased recycled paper. Since the double-sided printing operation can be performed immediately by using, the operability can be improved.

According to a second aspect of the present invention, in the first aspect of the present invention, at least one of the wetting means and the toner stripping means performs a wetting or stripping operation on a printed sheet conveyed during double-sided image formation. Since the double-sided image forming operation stop control means for stopping the double-sided image formation is provided, it is possible to prevent the image erasing device from acting on the printed paper during double-sided image formation. It is possible to prevent the image formed on the image from being accidentally erased.

According to a third aspect of the present invention, in the first aspect of the invention, there is provided double-sided image forming operation stop control means for stopping the wetting operation of the wetting means with respect to the printed paper conveyed during double-sided image formation. At least one of the wetting means, the toner peeling means, and the drying means is formed by a pair of rollers capable of normal rotation and reverse rotation, and the position of the printed sheet being conveyed is detected before the pair of rollers. Reversing operation start control for reversing the pair of rollers to reverse the pair of rollers after detecting the trailing edge of the printed sheet by the sheet position detecting section when reversing the sheet. Since the means is provided, it is possible to reverse the roller to start the reversing operation on the printed paper at the time of double-sided image formation, and thus the reversing path for reversing the paper. The short to be able to shorten the time required for reversing operation, it is possible to increase the production efficiency further.

According to a fourth aspect of the present invention, in the first, second or third aspect of the present invention, erased regenerated paper detecting means for detecting whether or not erased regenerated paper is stored in the reversal paper storage means is provided. If the erased recycled paper detecting means detects that the erased recycled paper is stored in the reverse sheet storage means during double-sided image formation, the stored erased recycled paper is discharged to the outside of the main body. Since double-sided printing operation control means is provided that causes the paper to perform double-sided printing operation after the paper is ejected, the printed paper for double-sided printing and the erased recycled paper are stored in the same reversal paper storage means during double-sided image formation. No more mixing
As a result, problems such as skew and paper jam can be eliminated, and the double-sided printing operation can be performed smoothly.

According to a fifth aspect of the present invention, in the first, second or third aspect of the present invention, there is provided recycled paper size detection means for detecting the recycled paper size of the erased recycled paper stored in the reversal paper storage means, When the double-sided image is formed, the recycled paper size detected by the recycled paper size detecting means is compared with the printing paper size of the printing paper to be printed detected by the printing paper size detecting means, and this printing paper size is reproduced. Since the double-sided printing operation control means for performing the double-sided printing operation using the erased recycled paper stored in the reversal paper storage means when the paper size is equal to or larger than the paper size is erased at the time of double-sided image formation. It is no longer necessary to separately set the used recycled paper separately, which enables immediate double-sided printing operation and improves operability. It is possible to improve the.

[Brief description of drawings]

FIG. 1 is a vertical sectional front view showing the configuration of an electrophotographic apparatus provided with an image erasing device according to a first embodiment of the present invention.

FIG. 2 is a vertical sectional front view showing a configuration of an electrophotographic apparatus provided with an image erasing device according to a second embodiment of the invention.

FIG. 3 is a vertical sectional front view showing the configuration of an electrophotographic apparatus provided with an image erasing device according to the third embodiment of the invention.

FIG. 4 is a diagram showing a configuration of an image erasing device arranged in a reversing path which is a first embodiment of the invention described in claim 2, and FIG. FIG. 3B is a front view showing the arrangement state of the image erasing device during double-sided image formation.

FIG. 5 is a vertical cross-sectional front view showing the configuration of an electrophotographic apparatus including an image erasing device according to a second embodiment of the invention.

FIG. 6 is a front view showing a configuration of an image erasing device arranged in a reversing path which is a third embodiment of the invention according to claim 2;

FIG. 7 is a front view showing a configuration of an image erasing device arranged in a reversing path which is a first embodiment of the invention according to claim 3;

FIG. 8 is a front view showing a configuration of an image erasing device arranged in a reversing path according to a second embodiment of the present invention.

FIG. 9 is a vertical sectional front view showing the configuration of an electrophotographic apparatus provided with an image erasing device according to a third embodiment of the invention.

FIG. 10 is a vertical cross-sectional front view showing the configuration of an electrophotographic apparatus including an image erasing device that is an embodiment of the invention described in claim 4.

FIG. 11 is a flowchart showing a double-sided printing operation control means.

FIG. 12 is a vertical sectional front view showing the configuration of an electrophotographic apparatus provided with an image erasing apparatus which is an embodiment of the invention as set forth in claim 5;

FIG. 13 is a flowchart showing a double-sided printing operation control means.

FIG. 14 is a vertical sectional front view showing the configuration of a double-sided copying machine as a conventional example.

FIG. 15 is a vertical cross-sectional front view showing the configuration of an image erasing apparatus which is a conventional example.

[Explanation of symbols]

 2 printing paper 3 printing paper storage means 5 latent image carrier 6 printing paper feeding means 7 visualization means 8 printed paper 9 transfer means 10 fixing means 11 paper reversing means 12 reversing paper storage means 13 refeeding means 34, 36 Reversing Path 43 Wetting Means 44 Toner Peeling Means 45 Erased Recycled Paper 46 Drying Means 62 Image Erasing Devices 64, 70 Double Sided Image Forming Operation Stop Control Means 71 Paper Position Detecting Means 72 Reversing Operation Start Control Means 74 Erased Recycled Paper Detection Means 75 double-sided printing operation control means 78 recycled paper size detection means 79 double-sided printing operation control means TS recycled paper size CS printing paper size

Claims (5)

[Claims] 1. A print sheet storage means for storing a print sheet which can be printed on both sides, a print sheet feeding means for feeding the stored print sheet, a latent image carrier, and a latent image carrier on the latent image carrier. Latent image forming means for forming a latent image on the latent image, visualizing means for visualizing the formed latent image with toner, and the visualized visible image on the latent image carrier. A transfer means for transferring to a printed paper sheet, a fixing means for heating and fixing the toner adhering to the printed paper sheet, and a paper reversing means for inverting the printed paper sheet on which the toner is printed and fixed on one side. A reversing sheet storage means for storing the reversed printed sheet, and the printed sheet for printing on the non-printed side of the reversed stored printed sheet. Re-feeding means to re-feed the paper feeding means In an electrophotographic apparatus provided with, in the reversing path of the paper reversing means between the fixing means and the reversal paper storing means, the toner on the surface of the printed paper having one side or both sides conveyed is printed. Wetting means for wetting, a toner peeling means for heating the printed paper after the wetting to peel off the toner adhering to the surface of the paper to obtain erased recycled paper, and the wet erasing after the toner is peeled off. An image erasing device having a drying means for drying the used recycled paper is provided, and the erased recycled paper from which an image has been erased by the image erasing device is discharged to the reversal paper storage means. Electrophotographic device. 2. At least one of the wetting means and the toner peeling means is provided with a double-sided image forming operation stop control means for stopping the operation of wetting or peeling on a printed sheet conveyed during double-sided image formation. The electrophotographic apparatus according to claim 1, wherein: 3. A double-sided image forming operation stop control means for stopping the wetting operation of the wetting means with respect to a printed sheet conveyed during double-sided image formation, which comprises the wetting means, the toner peeling means and the drying means. At least one is formed by a pair of rollers capable of forward and reverse rotation, and a sheet position detecting means for detecting the position of the printed sheet being conveyed is provided in front of the pair of rollers. 2. The reversing operation start control means for reversing the pair of rollers to start the reversing operation on the printed paper after detecting the trailing end of the printed paper by the detection means. Electrophotographic device. 4. An erased recycled paper detecting means for detecting whether or not erased recycled paper is stored in the inverted paper storage means, and the inverted paper storage means is provided by the erased recycled paper detection means during double-sided image formation. When it is detected that the erased recycled paper is stored inside, the stored erased recycled paper is discharged to the outside of the main body, and double-sided printing operation control means for performing double-sided printing operation after the discharge The electrophotographic apparatus according to claim 1, wherein the electrophotographic apparatus is provided with. 5. A recycled paper size detecting means for detecting the recycled paper size of the erased recycled paper stored in the reversal paper storage means is provided, and the recycled paper size detected by the recycled paper size detecting means during double-sided image formation. And the printing paper size of the printing paper to be printed detected by the printing paper size detecting means are compared, and when the printing paper size is equal to or larger than the recycled paper size, the paper is stored in the reversing paper storage means. 4. The electrophotographic apparatus according to claim 1, further comprising double-sided printing operation control means for performing a double-sided printing operation using the erased recycled paper.