JPH0749634A - Image forming device - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] To provide an image forming apparatus that forms and erases an image using a decolorizable toner. The present invention has image forming means for forming an image of decoloring toner on a transfer sheet S, and toner decoloring means for decoloring an image of decoloring toner formed on the transfer sheet, and The fixing means 10 of the image forming means is of a heat roller fixing type, and the toner erasing means is of a heat roller pair 11, 12.
In the image forming apparatus including the heat roller pair 11 and 12 of the fixing unit 10 and the heat roller pair 11 and 12 of the fixing unit 10 also serving as the heat roller pair of the erasing unit, the nip portion of the heat roller pair 11 and 12 in the toner erasing mode. Is controlled to be higher than the temperature in the image forming mode. [Effect] Even when the toner erasing means and the fixing means are combined, the amount of heat required for erasing can be given,
The erasing process can be performed completely.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus for forming and erasing an image using a decolorizable toner.

[0002]

2. Description of the Related Art In recent years, paper wastes discharged from offices have been attracting attention from the viewpoint of resource conservation in the problem of wastes becoming serious. The recycling of paper, so-called OA paper, is being called for. Recycling of OA paper, which is currently being carried out, means that the OA paper used for copying or printers is sorted and collected, and then it is reused as recycled paper after being subjected to dissolution, deinking, and papermaking at paper mills and the like. is there. However, at present, it is said that only about 5% of the OA paper consumed in offices of 2.5 million tons per year is collected.

On the other hand, OA in an office is such that OA paper is printed with a recording material such as toner or ink using a decolorizable colorant, and is erased and printed again when it is no longer needed.
Paper recycling is proposed. The outline of this decolorizable colorant is a recording material using a colorant composed of a cyanine dye and an ammonium salt of organic boron, for example, in an electrophotographic image forming apparatus, the above-mentioned colorant is used instead of carbon black as a colorant. When using a toner with a colorant,
Under general illumination, blue printing is possible, and the same visibility as in normal recording can be obtained. In this print recording method, the colorant can be made colorless by irradiating light near 820 nm, so that the recording can be erased. Therefore, by using such a decolorizable colorant recording material,
It is said that recycled paper can be reused relatively easily, which is effective for resource conservation, environmental conservation, and reduction of municipal solid waste.

Regarding a specific system for reusing OA paper using decoloring toner, the technology disclosed heretofore requires a dedicated erasing device for erasing the image of the decoloring toner formed on the paper. Met. In this case, since the image forming apparatus and the erasing apparatus are installed in the operating environment, the installation space is large, and there are many work procedures in which the sheets erased by the erasing apparatus are set again in the image forming apparatus. Therefore, it is considered that the image forming apparatus and the erasing apparatus are integrated, and the fixing apparatus of the image forming apparatus is also used as the erasing apparatus. On the other hand, as the fixing device, in addition to the usual heat roller fixing system, an infrared lamp is used as a fixing means for a toner image, and a radiant fixing device for fixing the toner by radiant heat from the infrared lamp, or the energy of the lamp is reduced for a short time. There is a flash fixing device that irradiates the surface to be fixed with radiation to fix the surface.

[0005]

When the fixing device of the image forming apparatus is also used as the erasing device, the following problems occur. (1) The amount of heat to be applied when the toner is decolored is larger than that when the toner is fixed. Therefore, when the fixing device is also used as the erasing device, there is a problem that the erasing toner cannot be completely erased by the control as it is due to insufficient heat quantity. (2) Decoloring the toner is intended to reuse the transfer paper. However, in the case of a heat roller fixing type fixing device, if the temperature of the heat roller pair is high, the state of the transfer paper may be deteriorated (moisture content, curl, etc.), and reuse may be hindered.

The present invention has been made in view of the above circumstances, and a first object thereof is to provide means for solving the above-mentioned problem (1) in an image forming apparatus which also functions as a fixing device as an erasing device. Especially. A second object is to provide a means for solving the above problem (2) in an image forming apparatus that also uses the fixing device as a decoloring device. A third object is to provide an image forming apparatus capable of reducing power consumption in addition to the first object. Furthermore, a fourth object is to provide an image forming apparatus capable of supplying an insufficient amount of heat and reducing power consumption in addition to the second object.

[0007]

In order to achieve the first object, the invention of claim 1 is an image forming means for forming an image of decoloring toner on a transfer paper, and an erasing color formed on the transfer paper. And a toner erasing unit for erasing the toner image, the fixing unit of the image forming unit is a heat roller fixing system, and the toner erasing unit is composed of a heat roller pair and a light emitting unit. Further, in the image forming apparatus in which the heat roller pair of the fixing unit also serves as the heat roller pair of the erasing unit, it is possible to control the temperature of the nip portion of the heat roller pair in the toner erasing mode to be higher than the temperature in the image forming mode. It has a feature.

In order to achieve the above second object, the invention of claim 2 erases the image of the decoloring toner formed on the transfer paper and an image forming means for forming an image of the decoloring toner on the transfer paper. A color roller toner erasing unit, the fixing unit of the image forming unit is a heat roller fixing system, and the toner erasing unit is composed of a heat roller pair and a light emitting unit;
Further, in the image forming apparatus in which the heat roller pair of the fixing unit also serves as the heat roller pair of the erasing unit, the temperature of the nip portion of the heat roller pair in the toner erasing mode is controlled to be lower than that in the image forming mode. Is characterized by.

In order to achieve the third object, the invention of claim 3 is an image forming means for forming an image of the decoloring toner on the transfer paper, and an image of the decoloring toner formed on the transfer paper is erased. A color toner erasing unit, the fixing unit of the image forming unit is a heat roller fixing system, and
In an image forming apparatus in which the toner erasing means is composed of a heat roller pair and a light emitting section, and the heat roller pair of the fixing means also serves as the heat roller pair of the erasing means, the heat roller pair in the toner erasing mode is The feature is that the linear velocity is controlled to be slower than in the image forming mode.

In order to achieve the above-mentioned fourth object, the invention of claim 4 is an image forming means for forming an image of decoloring toner on a transfer sheet, and an image of the decoloring toner formed on the transfer sheet is erased. A color roller toner erasing unit, the fixing unit of the image forming unit is a heat roller fixing system, and the toner erasing unit is composed of a heat roller pair and a light emitting unit;
Further, in the image forming apparatus in which the heat roller pair of the fixing unit also serves as the heat roller pair of the erasing unit, the pressure of the heat roller pair in the toner erasing mode is controlled to be larger than the pressure in the image forming mode. It is characterized by that.

[0011]

In the image forming apparatus of the present invention, the temperature of the nip portion of the heat roller in the toner erasing mode is higher than that in the image forming mode even when the erasing means and the fixing means of the toner are both used. For control, the amount of heat required for erasing can be provided.

In the image forming apparatus according to the second aspect of the present invention, even when the toner erasing means and the fixing means are combined, the temperature of the nip portion of the heat roller pair in the toner erasing mode is higher than that in the image forming mode. Since it is also controlled to be low, deterioration of the state of the transfer paper (water content, curl, etc.) can be suppressed.

In the image forming apparatus according to the third aspect of the present invention, the linear velocity of the heat roller pair in the toner erasing mode becomes slower than that in the image forming mode even when the toner erasing means and the fixing means are combined. Since the transfer paper is controlled as described above, it is possible to provide the transfer paper with a sufficient amount of heat required for erasing, and reduce the rating of the erasing light source to save power.

In the image forming apparatus of claim 4, even when the toner erasing means and the fixing means are combined, the pressing force of the heat roller pair in the toner erasing mode is larger than the pressing force in the image forming mode. Since the control is performed so that the pressure applied to the roller pair increases and the nip width increases when erasing, even if the set temperature is low, it is possible to give the transfer paper a sufficient amount of heat required for erasing. it can.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below based on the illustrated embodiments. FIG. 1 is a schematic configuration diagram of an image forming apparatus showing an embodiment of the present invention, which has an image forming mode and a toner erasing mode, and a toner fixing unit in the image forming mode and a toner erasing mode. 2 shows an example of the structure of a copying machine using the same pair of heat rollers as the erasing means in FIG. In FIG. 1, reference numeral 1 is a transfer paper stacking tray (or a paper feed cassette), and as the transfer paper S to be used, a new one, reused paper that has been decolorized, and an image-formed sheet for erasing from now on are used. There is something. Reference numeral 5 is a photoconductor, reference numerals 2 and 3 are developing devices, one of the developing devices 2 and 3 is a decoloring toner, and the other is a normal toner to develop an electrostatic latent image on the photoconductor 5. Turn into. In some cases, there is no developing device for normal toner. Reference numeral 4 denotes an exposure optical system, which includes a light source 41 for illuminating a document placed on the contact glass 17 and mirrors 42, 43, 44, 46 for exposing the photoconductor 5 with reflected light from the document. It is composed of 47, 48 and a lens 45 system. Reference numeral 6 is a charging charger for uniformly charging the photoconductor 5, 7 is a transfer charger for transferring the toner image on the photoconductor 5 to the transfer paper S, and 8 is a transfer paper S after the toner image transfer. Is separated from the photoconductor 5 by a separation charger, 9 is a cleaning device for removing residual toner and paper dust on the surface of the photoconductor 5 after transfer, and 16 is a residual charge on the surface of the photoconductor 5 after cleaning. A charge eliminating lamp for carrying out the operation, and a conveying belt 18 for conveying the transfer sheet S after the transfer / separation.

Reference numeral 10 is a fixing and erasing device which also serves as a fixing device during image formation and a erasing device during erasing. 11 and 12 in the fixing / decoloring device 10 are heat roller pairs, and one or both rollers of the heat roller pair are made of an elastic body, and a nip is formed in the contact portion by applying pressure between both rollers to transfer. The amount of heat is applied at the same time as the paper S is conveyed. Again 13
Is an erasing light source for erasing the toner on the transfer paper heated by the heat roller pair 11 and 12 when erasing.
If the wavelength is in the vicinity of nm, decoloring can be efficiently performed. Further, 14 is a paper discharge roller for discharging the transfer paper S after fixing or erasing, and 15 is a paper discharge tray.

In the copying machine having the structure shown in FIG. 1, the image forming mode and the toner erasing mode can be selected by the selection key of the operation section (not shown). When a new transfer sheet or a reused transfer sheet that has already been erased is set on the transfer sheet stack tray 1 and the image forming mode is selected,
A normal electrophotographic image forming operation is executed. That is, after the photoconductor 5 is uniformly charged by the charging charger 6, the image of the original document placed on the contact glass 17 is exposed on the photoconductor 5 by the exposure optical system 4 to form an electrostatic latent image. It Then, this electrostatic latent image is transferred to the developing devices 2 and 3
And then visualized with decolorizing toner or normal toner. The toner image on the photoconductor 5 is
A transfer charger 7 transfers the transfer paper S to the transfer paper S fed from the transfer paper stack tray 1, the transfer paper after transfer is separated from the photoconductor 5 by a separation charger 8, and is conveyed to a fixing / erasing apparatus 10 by a conveyor belt 18. Fixing and erasing device 1
The toner image is fixed on the transfer sheet by the pair of heat rollers 11 and 12 in 0, and the sheet is discharged to the sheet discharge tray 15 by the sheet discharge roller 14.

Further, when the image-formed transfer sheet S to be erased is set in the transfer sheet stacking tray 1 and the toner erasing mode is selected, the transfer sheet fed from the transfer sheet stacking tray 1 is selected. Is directly conveyed to the fixing / decoloring apparatus 10 by the conveying belt 18 and heated by the pair of heat rollers 11 and 12 in the fixing / decoloring apparatus 10, and then is turned on by the decoloring light source 13.
Light having a wavelength of about 20 nm is irradiated to erase the color of the color-erased toner image, and the paper is discharged to the paper discharge tray 15 by the paper discharge roller 14.

By the way, there is a characteristic that the amount of heat to be applied when the toner is erased is larger than that when the toner is fixed. Therefore, when the fixing device is also used as the erasing device as in the above copying machine, the erasing toner may not be completely erased by the control as it is due to insufficient heat quantity. Therefore, in the invention of claim 1, the heat roller pair 1 in the toner erasing mode is used.
The temperatures of the nip portions 1 and 12 are controlled to be higher than the temperature in the image forming mode. Here, FIG. 2 is a flowchart of control in the decoloring mode for giving a set temperature of the heat roller pair different from that during image formation. That is, when the toner erasing mode is set, the set temperature T of the heat roller pair 11 and 12 is switched to the set temperature T ₁ higher than the set temperature T ₀ at the time of image formation by the temperature setting means (not shown). . As described above, when the decoloring toner is used, the amount of heat required for decoloring is larger than the amount of heat required for fixing at the time of image formation. Therefore, a good erasing condition cannot be obtained by simply using the fixing device and the erasing device together.
When the erasing mode is selected, the control is performed as shown in FIG. 2, and as shown in FIG. 3, the set temperature in the erasing mode is raised as compared with that in the image forming mode, so that the insufficient heat amount is eliminated, and the erasing is performed well. Can be done.

Next, as the purpose of using the decolorizable toner,
There are times when we want to make effective use of resources, that is, to reuse transfer paper as many times as necessary. In a normal fixing device, the passage of the paper is considered only up to twice (during double-sided copying). Generally, the transfer paper expands when heat is applied, and contracts due to evaporation of water. In this state, a wrinkle occurs due to the passage of the heated heat roller pair, and an excessive curl causes a paper jam. Therefore,
The transfer paper cannot be reused many times by simply using both the fixing device and the erasing device. Therefore, in the invention of claim 2, the temperature of the nip portion of the heat roller pair 11, 12 in the toner erasing mode is controlled to be lower than that in the image forming mode. That is, as shown in FIG. 4, the set temperature T ₀ in the image erasing mode is more than the set temperature T ₀ in the image forming mode.
Lowering ₁ will solve this problem. However, in this case, since the decoloring performance is deteriorated, the decolorized transfer paper may be used when the image quality is not important, such as for test printing. Also in the case of controlling as shown in FIG. 4, complete erasing can be performed by increasing the light amount of the erasing light source 13.

By the way, as described above, since a larger amount of heat is required at the time of erasing the image than at the time of fixing the image, in the invention of claim 1, the heat roller pair 1 in the toner erasing mode is used.
Although the temperature of the nip portions of 1 and 12 is controlled to be higher than the temperature in the image forming mode, heat is applied to the transfer paper from the nip portions of the heat roller pairs 11 and 12, so that the heat is applied to the transfer paper. It is also effective to provide a means for reducing the linear velocity of the transfer paper passing through the roller pair 11 and 12 when the color is erased. That is, as shown in the flowchart of FIG. 5, the linear velocity setting means (not shown) controls the linear velocity V ₁ of the heat roller pair in the toner erasing mode to be slower than the linear velocity V ₀ in the image forming mode. To do. In this way, by lowering the linear velocity at the time of erasing, the transfer paper passes through the nip and the heat roller pair 1
Can receive a sufficient amount of heat from 1, 12 and
Since it takes longer to pass under the erasing light source 13, even if the rating of the erasing light source 13 is lowered, it is possible to surely erase the color, and there is an advantage of saving power.

In the second aspect of the present invention, when the temperature of the heat roller pair is high, the condition of the transfer paper may be deteriorated (moisture content, curl, etc.) and the reuse may be hindered. Although the temperature of the nip portion of the heat roller pair 11 and 12 in the erasing mode is controlled to be lower than that in the image forming mode,
In this case, there is a drawback that the decoloring performance is deteriorated. Therefore, in addition to this configuration, as in the invention of claim 4, the pressing force of the heat roller pairs 11 and 12 in the toner erasing mode is controlled to be larger than the pressing force in the image forming mode. That is, a heat roller pair pressurizing force varying means (not shown) is provided, and the set pressurizing force F ₁ of the heat roller pairs 11 and 12 in the toner erasing mode is set to be higher than the set pressurizing force F ₀ in the image forming mode according to the flowchart of FIG. Control so that it becomes larger. Here, FIG. 7 shows a pair of heat rollers 11, 1.
2 shows the nip in No. 2, the nip width changes as shown in FIG. As the nip width increases, the amount of heat given to the passing transfer paper increases, so that the temperatures of the heat roller pairs 11 and 12 can be lowered,
The drawback of claim 2 can be compensated.

[0023]

As described above, in the image forming apparatus according to the first aspect of the present invention, the temperature of the nip portion of the heat roller in the toner erasing mode can be controlled even when the toner erasing means and the fixing means are combined. Since the temperature is controlled to be higher than the temperature in the image forming mode, the amount of heat required at the time of erasing can be given, and the erasing process can be performed completely.

In the image forming apparatus of the second aspect, even when the toner erasing means and the fixing means are combined, the temperature of the nip portion of the heat roller pair in the toner erasing mode is higher than that in the image forming mode. Since it is controlled to be low, it is possible to suppress deterioration of the state of the transfer paper (moisture content, curl, etc.), and it is possible to repeatedly use the transfer paper after decoloring.

In the image forming apparatus of the third aspect, even when the toner erasing means and the fixing means are combined, the linear velocity of the heat roller pair in the toner erasing mode becomes slower than that in the image forming mode. Since the transfer paper is controlled as described above, it is possible to provide the transfer paper with a sufficient amount of heat required for erasing, and reduce the rating of the erasing light source to save power.

In the image forming apparatus according to the fourth aspect, even when the toner erasing means and the fixing means are combined, the pressing force of the heat roller pair in the toner erasing mode is larger than that in the image forming mode. Since the control is performed so that the pressure applied to the roller pair increases and the nip width increases when erasing, even if the set temperature is low, it is possible to give the transfer paper a sufficient amount of heat required for erasing. Yes, and
As in the second aspect, the transfer paper can be repeatedly subjected to the decoloring process and used.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an image forming apparatus showing an embodiment of the present invention.

FIG. 2 is a diagram showing a control example according to the present invention, and is a flowchart showing only a temperature setting control portion of a heat roller pair.

FIG. 3 is a diagram showing an example of control of the image forming apparatus according to claim 1, showing an example of a temperature control state of a heat roller pair in an image forming mode and a color erasing mode.

FIG. 4 is a diagram showing a control example of the image forming apparatus according to a second aspect of the present invention, which is a diagram showing an example of a temperature control state of a heat roller pair in an image forming mode and a color erasing mode.

FIG. 5 is a diagram showing an example of control of the image forming apparatus according to claim 3, and is a flowchart showing only the linear velocity control portion of the heat roller pair.

FIG. 6 is a diagram showing an example of control of the image forming apparatus according to a fourth aspect of the present invention, and is a flowchart showing only a pressing force control portion of the heat roller pair.

FIG. 7 is an explanatory diagram of a pressing force of a heat roller pair and a nip width.

FIG. 8 is a diagram showing a relationship between a pressing force of a heat roller pair and a nip width.

[Explanation of symbols]

 1 ... Transfer paper stacking tray 2, 3 ... Developing device 4 ... Exposure optical system 5 ... Photosensitive member 6 ... Charging charger 7 ... Transfer charger 8 ... Separation charger 9 ...・ Cleaning device 10 ・ ・ ・ Fixing / erasing device 11, 12 ・ ・ ・ Heat roller 13 ・ ・ ・ Erasing light source

Front page continuation (51) Int.Cl. ⁶ Identification number Office reference number FI Technical display location G03G 15/20 102 15/22 103 Z 21/00 (72) Inventor Yoshiyuki Kimura Nakamagome 1-chome, Ota-ku, Tokyo No. 3-6 in Ricoh Co., Ltd. (72) Inventor Masahiko Sato 1-3-3 Nakamagome, Ota-ku, Tokyo No. 6 in-Ricoh Co., Ltd. (72) Masami Okamoto 1-3-3 Nakamagome, Ota-ku, Tokyo No. 6 in Ricoh Co., Ltd. (72) Kenichi Hasegawa 1-33 Nakamagome, Ota-ku, Tokyo No. 6 in Ricoh Co., Ltd. (72) Masahisa Ehara 1-3-6 Nakamagome, Ota-ku, Tokyo -In stock company Ricoh (72) Inventor Keizo Yasuda 1-3-6 Nakamagome, Ota-ku, Tokyo-In stock company Ricoh (72) In-house Yasuhisa Kato 1-3-6 Nakamagome, Ota-ku, Tokyo-Shares Inside Ricoh Company (72) Inventor Genichi Yasui 1-3-3 Nakamagome, Ota-ku, Tokyo

Claims (4)

[Claims] 1. An image forming unit for forming an image of decoloring toner on a transfer sheet, and a toner decoloring unit for decoloring an image of decoloring toner formed on the transfer sheet, and the image forming unit. Image forming means in which the fixing means is a heat roller fixing method, the toner erasing means is composed of a heat roller pair and a light emitting portion, and the heat roller pair of the fixing means also serves as the heat roller pair of the erasing means. In the image forming apparatus, the temperature of the nip portion of the heat roller pair in the toner erasing mode is controlled to be higher than the temperature in the image forming mode. 2. An image forming means for forming an image of the decoloring toner on the transfer paper, and a toner decoloring means for decoloring the image of the decoloring toner formed on the transfer paper, and the image forming means. Image forming means in which the fixing means is a heat roller fixing method, the toner erasing means is composed of a heat roller pair and a light emitting portion, and the heat roller pair of the fixing means also serves as the heat roller pair of the erasing means. In the image forming apparatus, the temperature of the nip portion of the heat roller pair in the toner erasing mode is controlled to be lower than that in the image forming mode. 3. An image forming means for forming an image of the decoloring toner on the transfer paper, and a toner decoloring means for decoloring the image of the decoloring toner formed on the transfer paper, and the image forming means. Image forming means in which the fixing means is a heat roller fixing method, the toner erasing means is composed of a heat roller pair and a light emitting portion, and the heat roller pair of the fixing means also serves as the heat roller pair of the erasing means. In the image forming apparatus, the linear velocity of the heat roller pair in the toner erasing mode is controlled to be slower than that in the image forming mode. 4. An image forming unit for forming an image of decoloring toner on a transfer sheet, and a toner decoloring unit for decoloring an image of decoloring toner formed on the transfer sheet, and the image forming unit. Image forming means in which the fixing means is a heat roller fixing method, the toner erasing means is composed of a heat roller pair and a light emitting portion, and the heat roller pair of the fixing means also serves as the heat roller pair of the erasing means. In the image forming apparatus, the pressing force of the heat roller pair in the toner erasing mode is controlled to be larger than the pressing force in the image forming mode.