JP2002258641A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device capable of outputting an image in a short waiting time though a fixing means has single device constitution, and yielding the clear image because the gloss of an image surface and an outputted image obtained by projecting OHP film are clear. SOLUTION: In this image forming device, transfer material P on which the image is fixed once by a fixing device 21 is carried again in a state where a toner image surface is set on a pressure roller 26 side and the image is fixed on the material P by the device 21, and a gloss uniformizing mode in which at least optional image formation is not performed when the material P is carried for the second time is prepared in the image forming device.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic image forming apparatus such as a copying machine or a laser beam printer.

[0002]

2. Description of the Related Art Conventionally, various systems such as an electrophotographic system, a thermal transfer system, and an ink jet system have been used as an image forming apparatus. Among them, the one using the electrophotographic method is superior to other methods in terms of high speed, high image quality, and quietness, and is widely used as an image forming engine of a copying machine, a page printer, and the like.

In the electrophotographic system, an image is formed by toner particles on a transfer material such as paper using electrostatic force, and then the toner image is melted on the transfer material by heat and pressure applied by a fixing device. It is fixed (fixed) and becomes stable. 2. Description of the Related Art In recent years, electrophotographic image forming apparatuses have been improved in functionality such as color compatibility and duplex capability.

[0004] The configuration of a conventional fixing device will be described with reference to FIG. The fixing device 101 is configured such that a transfer material P on which an unfixed toner image 105 is mounted can pass through a contact nip portion 104 of two heating rollers including a temperature-adjusted fixing roller 102 and a pressure roller 103. I have.

When the unfixed toner image 105 passes through the nip 104, the unfixed toner image 105 is heated and pressed by the fixing roller 102 and the pressure roller 103 and is fixed on the transfer material P. Each roller
The thermistors 106a and 106b are in contact with the surfaces of the rollers 102 and 103, and the temperatures of the rollers 102 and 103 are adjusted based on the temperatures detected by the thermistors 106a and 106b.

Further, each of the rollers 102 and 103 has a halogen heater 107a and 107b at the center thereof.
The radiant energy generated from 107b is absorbed by aluminum cores 108a and 108b inside rollers 102 and 103 and heated.

2 mm thick around the aluminum cores 108a and 108b
Elastic layers 109a, 109b made of silicone rubber are provided, and PFA (tetrafluoroethylene / perfluoroalkyl) is provided on the outer surfaces of the rollers 102, 103 in order to prevent toner and paper powder from sticking. Ether copolymer / tetrafluoroethylene / perfluoroalkylvinyl ether copolymer resin, PTFE (polytetrafluoroethylene / 4-fluoroethylene resin), FEP (tetrafluoroethylene / hexafluoropropylene copolymer / 4)
Coating layer 110 made of a resin having good releasability and heat resistance, such as fluorinated ethylene and hexafluoropropylene copolymer resin)
a, 110b are provided.

The first reason for providing the elastic layers 109a and 109b on each of the rollers 102 and 103 is to secure a sufficient fixing nip width with the rollers 102 and 103 having a relatively small diameter. This is for fixing the toner image surface evenly.

Without the elastic layers 109a and 109b, the surface of the fixing roller 102 cannot follow irregularities due to the surface of the transfer material P or the presence or absence of the toner layer, and the difference in hitting depending on the location appears as uneven gloss of the image. . A case where the fixing roller 102 has a sufficient elastic layer 109a as in the fixing device 101 shown in FIG. 4 is referred to as a soft roller type fixing device.

[0010]

However, in the conventional example described above, the fixing roller 102 and the pressure roller 103 are provided with the elastic layers 109a and 109b having a relatively large thickness (2 mm), so that the halogen heater 107a is provided. , 107b absorb the radiant heat and generate heat, and the distance from the aluminum core bars 108a, 108b to the surfaces of the rollers 102, 103 for heating the transfer material P becomes longer, and it takes time for the heat to reach the surfaces of the rollers 102, 103. However, there is a problem that heat transfer is poor. Especially elastic layers 109a, 10
The materials used for 9b generally have low thermal conductivity, exacerbating this problem.

Further, the aluminum cores 108a and 108b and the elastic layer 10
Since it is necessary to heat the whole of 9a and 109b, the whole heat capacity becomes large, and it takes time to raise the temperature of each of the rollers 102 and 103.

Therefore, after supplying power to the halogen heaters 107a and 107b for these two reasons, a large waiting time (wait time) is required for raising the temperature of each of the rollers 102 and 103 to a temperature suitable for fixing the toner image. There was a problem that it was necessary.

Further, in order to shorten the wait time, the halogen heater 107 of each of the rollers 102 and 103 is used even when the apparatus is on standby.
Although power is continuously supplied to a and 107b, it also wastes energy and blocks the toner because it heats up inside the machine (they become semi-molten and solidify). Such problems are likely to occur, and in some cases, additional members such as cooling fans are required,
There are problems such as an increase in the cost of the entire apparatus.

In order to solve such a problem, as shown in FIG. 5, there has been proposed a fixing device 201 which employs a heating device of a film heating type in place of the fixing roller 102.
The fixing device 201 can improve the above-described problems of heat transfer and heat capacity, and can shorten the wait time after power is turned on.

The configuration of the fixing device 201 will be described below. The fixing device 201 employs, as a heating device, a fixing film unit 202 configured to press the heater 204 against the transfer material P and heat the transfer material P via a thin fixing film 203.

The fixing film 203 is formed, for example, by forming a release layer having a thickness of 10 μm on the surface of a heat-resistant resin having a thickness of about 50 μm. The heater 204 is provided on a ceramic substrate having a width of 1 cm or less and a thickness of 1 mm or less. In which a resistance heating element is formed.

Reference numeral 205 denotes a pressure roller disposed to face the fixing film unit 202 via the transfer material P. In the fixing device 201 having such a configuration, since the distance between the heat generating portion (the position of the heater 204) and the heating portion (the surface of the fixing film 203) in contact with the toner on the transfer material P to be heated is short, the heat transfer is excellent. And a fixing film unit 202 as a heating device.
Since the whole has a low heat capacity, it is possible to raise the temperature of the fixing nip portion 206 to a temperature at which the toner image can be fixed in a short time after power is supplied to the heater 204.

As a heating means of the fixing device 201, other than the above-described film heating method, a method of directly heating a portion closer to a heating portion by using magnetic induction heating has been proposed.

Although the elastic layer of the fixing film 203 is omitted in the fixing device 201 shown in FIG. 5, even if an elastic layer is separately provided, the same effect can be maintained as long as the thickness is 500 μm or less. I can do it.

However, in the fixing device 201 shown in FIG. 5, the elastic layer is omitted from the viewpoint of heat capacity and heat transfer, or a thin layer having a thickness of 500 μm or less is used. When fixing is performed on the fixing film unit 202 side, the following problems cannot be avoided.

That is, since the unevenness of the surface of the transfer material P itself cannot be sufficiently absorbed by the elastic layer, the fixing film 203
A portion where heat and pressure are applied in contact with the surface and a portion where the heat and pressure are not applied are formed, and the influence appears as uneven gloss of the toner image.

Further, the transfer material P having a smooth surface with little unevenness
Even when the toner is used, the step caused by the difference in the thickness of the toner layer of the formed toner image, the uneven thickness of the base of the fixing film 203 and the heater 204, the unevenness of the surface, and the unevenness of the heat generated by the heater 204 are sufficiently absorbed. And the glossiness of the toner image becomes uneven.

Further, a fixing film unit as shown in FIG.
When 202 is used, the fixing film 203 is
7 is in a tension-free state because it is only rotatably supported by the fixing film 7, and the fixing film after the toner image on the transfer material P has passed through the nip portion 206 as compared with the fixing roller 102 shown in FIG. The separation between 203 and the toner image surface of the transfer material P was unstable, which contributed to uneven gloss.

In particular, when an image is formed on an OHP sheet, uneven gloss is further emphasized as uneven brightness when projected on a screen, which is a serious problem.

In general, when a color image mainly composed of characters, figures, and tables used for business purposes is output on plain paper, there is a tendency to reduce the wait time. On the other hand, a photographic image is output. In some cases or when outputting an image on glossy paper or an OHP sheet, uniformity of gloss is often required.

In view of the above, conventionally, the configuration of the fixing device required to emphasize the reduction of the wait time or the importance of the uniformity of the gloss of the toner image surface is different. It was impossible to respond.

The present invention solves the above-mentioned problems, and
The purpose is to provide an image forming apparatus capable of outputting an image with a short wait time while using a single fixing device, and capable of obtaining a clear image with a uniform gloss on the image surface. Is to be provided.

[0028]

To achieve the above object, a representative image forming apparatus according to the present invention comprises an image forming means for forming a toner image on a transfer material, and a toner on the transfer material. In an image forming apparatus having a fixing unit for fixing an image, the fixing unit has at least a heating unit, and a pressing unit facing the heating unit via a transfer material,
The heating unit has an elastic layer having a thickness of 0 or more and 500 μm or less between a heating unit and the surface of the heating unit; the pressing unit has an elastic layer having a thickness of 500 μm or more; A first operation mode in which a toner image is formed on a transfer material, the image is fixed with the toner image surface of the transfer material on the side of the heating unit, and a completed image is output; A second operation mode in which the transfer material is fixed so that the toner image surface on which the transfer material is fixed in the first operation mode passes through the fixing unit with the toner image surface facing the pressure unit. In the second operation mode, at least arbitrary image formation is not performed.

Since the present invention is configured as described above, the first
In the second operation mode, the transfer material output in the first operation mode is transported so that the toner image surface fixed in the first operation mode is passed through the fixing unit with the toner image surface facing the pressure unit. By not performing at least any image formation, the second transfer of the transfer material in the uniform gloss mode fixes the toner image surface on the pressing means side having a sufficient elastic layer having a thickness of 500 μm or more. Due to the effect of the elastic layer, the surface of the pressing means can follow various irregularities and thickness irregularities such as irregularities on the surface of the transfer material itself and differences in the thickness of the toner layer of the toner image, and uniform heat and pressure. You can call it. As a result, the gloss on the surface of the toner image and the brightness of the transmitted image on the OHP sheet can be made uniform.

[0030]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As an example of an image forming apparatus according to the present invention, an embodiment applied to an electrophotographic color image forming apparatus will be specifically described with reference to the drawings. FIG. 1 is a schematic cross-sectional explanatory view showing a configuration of an image forming apparatus according to the present invention, and FIG. 2 is a schematic cross-sectional explanatory view showing a state in which a toner image formed on a transfer material is conveyed with a heating unit side in a fixing unit. FIG. 3 is a schematic cross-sectional explanatory view showing a state in which the toner image surface formed on the transfer material is conveyed with the fixing unit facing the pressing unit.

<First Embodiment> In FIG. 1, the image forming apparatus of the present embodiment is an image forming apparatus employing an intermediate transfer system, and has an automatic double-side mechanism as a known automatic double-sided conveying means. At least the first transfer material P described later
From the first transfer to the second transfer of the transfer material P can be automatically performed.

In FIG. 1, a portion indicated by a solid line is a transfer route of the transfer material P in the first operation mode, and a portion indicated by a dotted line is a transfer route of the transfer material P by the above-described automatic double-sided mechanism. Hereinafter, a configuration of an electrophotographic color image forming apparatus will be described in detail with reference to FIG.

The image forming system shown in FIG. 1 is a system known as an intermediate transfer system among electrophotographic systems. First, an electrophotographic photosensitive drum 1 which is an image forming means and serves as an image carrier for carrying a toner image is driven to rotate counterclockwise as indicated by an arrow in FIG.
As a result, a negative charge is applied, and the negative charge is uniformly applied to -600V.

Thereafter, the scanning light 4 based on the image data from the laser exposure optical system 3 and the like is irradiated onto the uniformly charged surface of the photosensitive drum 1 to remove a part of the negative charges, and the surface of the photosensitive drum 1 is removed. Is formed with an electrostatic latent image corresponding to the image. Note that the potential of the latent image portion is approximately -200V.

On the other hand, a black developing device 5, a magenta developing device 6, a cyan developing device 7, and a yellow developing device 8 containing toner of each color as a developer are shown in a rotary device 14 near the photosensitive drum 1 in FIG. When the rotary device 14 revolves every 90 degrees, the rotary device 14 is sequentially disposed at the developing position facing the photosensitive drum 1, and the toner of each color is formed on the photosensitive member on which the electrostatic latent image is formed. It is supplied to the surface of the drum 1. FIG. 1 shows a state where the black developing device 5 is arranged at the developing position.

Each of the developing devices 5 to 8 is provided with developing means for supplying a toner of each color to the surface of the photosensitive drum 1 on which the electrostatic latent image is formed to form a toner image, facing the photosensitive drum 1. Developing rollers 5a to 8a are provided.

In FIG. 1, a black developing unit 5 is opposed to the photosensitive drum 1, and a fixed amount of black toner charged to a negative polarity is placed on a developing roller 5a provided in the black developing unit 5. The developing roller 5a is supplied with a developing bias voltage from a bias power supply (not shown).

The developing bias voltage is set to an appropriate value between the charging potential and the potential of the latent image (exposed portion) to perform development for selectively adhering toner to the electrostatic latent image on the photosensitive drum 1. I can do it.

The single-color toner image formed on the photosensitive drum 1 in this manner is transferred to the intermediate transfer member rotating at a substantially constant speed in synchronization with the photosensitive drum 1 in a clockwise direction indicated by an arrow in FIG. The primary transfer is sequentially performed on the intermediate transfer belt 9.

Reference numeral 10 denotes a transfer roller serving as a primary transfer means for primary-transferring the toner image formed on the photosensitive drum 1 onto the intermediate transfer belt 9. , 200V-700
V) is applied.

1 from the photosensitive drum 1 to the intermediate transfer belt 9
After the next transfer, the toner remaining on the surface of the photosensitive drum 1 is removed by the cleaning device 17.

During full-color image formation (full-color mode)
The above steps are sequentially performed for the respective color developing units 5 to 8 in synchronization with the rotation of the intermediate transfer belt 9 to form a four-color superimposed color image on the intermediate transfer belt 9. At the time of monochrome image formation
(Single color mode) shows throughput (transfer efficiency of transfer material P)
For the sake of shortening, the above process is performed only for the developing device of the target color (for example, black).

When the toner image is formed on the intermediate transfer belt 9 in this manner, the toner image transferred on the intermediate transfer belt 9 is secondarily transferred onto the transfer material P on the rear surface of the transferred transfer material P. A secondary transfer roller 11 serving as a secondary transfer unit is brought into contact with the toner image, and a toner image on the intermediate transfer belt 9 is collectively transferred onto the transfer material P by a positive bias voltage (for example, 1 kV) applied from a bias power supply (not shown). Then, secondary transfer is performed.

On the other hand, a transfer material cassette serving as a transfer material supply unit
The transfer material P set on the transfer material tray 18 or the transfer material tray 20 is selectively fed by feed rollers 23 and 24, respectively, and is registered with a pair of registration rollers at a predetermined timing so as to be ready for the secondary transfer.
The toner image transferred to the nip portion between the intermediate transfer belt 9 and the secondary transfer roller 11 by the transfer roller 22 and transferred to the intermediate transfer belt 9 by the action of the secondary transfer roller 11 is secondarily transferred to the transfer material P.

When the above process is completed, the toner remaining on the intermediate transfer belt 9 after the secondary transfer is removed by a cleaning device.
The charge is removed from the intermediate transfer belt 9 by a charge remover (not shown). As the static eliminator, AC
Often a corona charger is used.

In general, an electrode is provided on the back surface of the intermediate transfer belt 9 in order to increase the charge removal efficiency. In addition,
In FIG. 1, 16 is a tension roller, 15 is a drive roller, 12
Denotes a secondary transfer facing roller.

The intermediate transfer belt 9 usually has a thickness of 70
PVdF (polyvinylidene fluoride) having a volume resistivity of about 10 ¹⁰ Ωcm to about ^{10 16} Ωcm, polyamide,
Polyimide, PET (polyethylene terephthalate),
Resin film belt such as polycarbonate and 0.5mm ~
It is possible to use a rubber belt or the like in which a high resistance resin layer having a thickness of several tens μm and a good releasability is provided on a low resistance rubber base layer having a thickness of about 2 mm.

The full-color toner image transferred onto the transfer material P is then fused and fixed on the transfer material P by passing through a fixing device 21 serving as a fixing means, and becomes an output image of the image forming apparatus.

The fixing device 21 is a fixing device employing a film heating type heating device as shown in FIGS. Reference numeral 25 denotes a heating unit, which is a fixing film unit configured as a heating device, and reference numeral 26 is a pressing roller serving as a pressing unit facing the fixing film unit 25 via the transfer material P.

A fixing film unit 25 serving as a heating device
Is provided with a ceramic heater 28 serving as a heat generating portion inside a heat-resistant thin layer film (fixing film) 27 formed in an endless shape. Fixing film 27 in this embodiment
Is, for example, PFA on a base layer made of a polyimide resin molded into a cylindrical shape having a thickness of 50 μm and a diameter of 24 mm.
A 10 μm-thick surface layer made of a high release material such as (tetrafluoroethylene / perfluoroalkyl ether copolymer) is formed.

The base layer of the fixing film 27 may be made of another heat-resistant resin or metal. Further, an elastic layer having a thickness of 500 μm or less may be provided between the base layer and the surface layer of the fixing film 27. According to the study of the present inventor, when the thickness of the elastic layer is 500 μm or more, the effect of shortening the wait time is reduced.

Therefore, the fixing film unit 25 serving as the heating means may be provided with an elastic layer having a thickness of 0 to 500 μm between the ceramic heater 28 serving as the heat generating portion and the surface of the fixing film 27. preferable.

The ceramic heater 28 has a length of 270 mm and a width of 8
The resistance heating element pattern is formed on a substrate made of alumina, aluminum nitride, or the like, which is molded to a thickness of 0.7 mm and a thickness of 0.7 mm. The thermistor 29 is provided on the non-contact surface of the ceramic heater 28 with the fixing film 27.
Thus, the temperature of the ceramic heater 28 is detected to perform temperature control.

Reference numeral 30 denotes a film guide, which plays a role of holding the ceramic heater 28 and guiding the running of the fixing film 27. The fixing film 27 is rotatably supported by a film guide 30.

A ceramic heater 28 provided integrally with the film guide 30 is pressed by a pressing mechanism (not shown) toward the pressing roller 26 with a total pressure of 13 kg.
As a result, the fixing film 27 rotatably supported by the film guide 30 is pressed against the pressure roller 26.

The pressure roller 26 is provided with a 3.5 mm thick silicone rubber elastic layer 32 on an aluminum core metal 31 having an outer diameter of 13 mm, and further thereon a 20 μm thick PFA as a release layer.
(Tetrafluoroethylene / perfluoroalkyl ether copolymer), FEP (tetrafluoroethylene / hexafluoropropylene copolymer / 4-tetrafluoroethylene)
A coating layer 33 made of propylene hexafluoride copolymer resin) was used. The product hardness of the pressure roller 26 is 50 degrees
(ASKER-C load 5.88N (600gf)).

The thickness of the silicone rubber elastic layer 32 of the pressure roller 26 serving as a pressure means is preferably 500 μm or more.

The width of the fixing nip portion 34 formed by receiving the pressing force from the ceramic heater 28 of the fixing film unit 25 and deforming the elastic layer 32 of the pressing roller 26 is about 6.5 mm. In the present embodiment, the pressure roller 26 is driven to rotate clockwise in FIG. 2, and the fixing film 27 is pressed by the frictional force acting on the contact portion (fixing nip portion 34) with the pressure roller 26. And slides on the ceramic heater 28 and the film guide 30 to rotate in the counterclockwise direction indicated by the arrow in FIG.

[0059] For example, the normal image forming time for forming an image on the transfer material P such as plain paper having a basis weight of ^{60g / m 2 ~100g / m 2} ( first operating mode), the pressure roller 26 is 120mm In addition to being driven to rotate at a peripheral speed of / sec, energization of the ceramic heater 28 is adjusted so that the fixing nip portion 34 has a temperature suitable for fixing a toner image.

After completing the transfer process, the transfer material P on which the unfixed toner image 35 is placed is guided to the fixing nip 34, where the pressure applied by the fixing nip 34 and the fixing film
The unfixed toner image 35 is melted and fixed on the transfer material P by the heat transmitted from the ceramic heater 28 via 27.

As a result of employing the above-described film heating type heating device, the fixing device 21 of the present embodiment has low heat capacity and high heat transfer, and the temperature of the fixing nip portion 34 rises quickly,
Wait time can be reduced.

On the other hand, as described above, the fixing film unit 25 serving as a heating means on the toner image side (upper side in FIG. 2) of the transfer material P does not have an elastic layer or has a thin layer. , The uneven gloss of the toner image, O
Irregularities in brightness and the like when the HP sheet is projected are likely to occur.

In the present embodiment, the image forming apparatus can output an image with improved gloss unevenness of a toner image and uneven brightness when an OHP sheet is projected without changing the configuration of the fixing device 21. A uniform gloss mode (second and third operation modes) as a new image forming mode was prepared.
Note that the image forming mode (first operation mode) for performing normal image forming is hereinafter referred to as “normal mode”.

In the gloss uniform mode according to the present embodiment, after the first conveyance in which the toner image surface of the transfer material P is fixed to the fixing film unit 25 side in the same manner as in normal image formation, the transfer material is transferred by the automatic double-sided conveyance mechanism. The sheet P is reversed and fed again, and the transfer material P is passed through the fixing device 21 with the toner image side of the transfer roller 26 side, and the second transfer for fixing again is performed.

In the gloss uniform mode, a mode in which the first transport and the second transport are performed as a set is referred to as a third operation mode, and a mode in which only the second transport is performed independently is referred to as a second operation mode.

FIG. 3 shows a state in which the transfer material P on which the toner image has been formed in the first transfer is passing through the fixing device 21 with the toner image surface facing the pressure roller 26. In FIG. 3, 35 '
Indicates a toner image fixed in the first conveyance.

Further, in this embodiment, since the image forming apparatus is provided with an automatic double-sided conveying mechanism in advance, when the user designates the uniform gloss mode, the above-described series of operations (transporting up to the second time) are automatically performed. It is performed.

As described above, in the second transfer of the transfer material P in the uniform gloss mode, the toner image surface is fixed by the pressure roller 26 having the elastic layer 32 having a sufficient thickness. By the effect, the surface of the pressure roller 26 can follow irregularities and uneven thickness due to the difference in the thickness of the toner layer of the toner image including irregularities on the surface of the transfer material P itself,
Heat and pressure can be applied uniformly. As a result, the gloss of the surface of the toner image and the brightness of the image transmitted through the OHP sheet and projected on the screen can be made uniform.

In the fixing device 21 of the present embodiment, a fixing nip portion
It is necessary to secure the thickness of the elastic layer 32 of the pressure roller 26 to 3.5 mm. According to the study of the inventor, in order to make the toner image surface uniform in the second transfer of the transfer material P in the uniform gloss mode, the thickness of the pressure roller 26 is 500 μm.
It has been found that the above elastic layer 32 is sufficient.

On the other hand, in the gloss uniform mode of this embodiment,
At the time of the second conveyance in which the toner image surface fixed on the transfer material P is inverted, it is not necessary to form a toner image on the back surface of the toner image surface of the transfer material P.

On the other hand, careless toner image formation causes an offset or the like in the fixing unit. Therefore, the image formation is stopped when the transfer material P is transported for the second time, or the image to be formed is limited ( That is, it is necessary to prevent any image formation.

Therefore, in the present embodiment, the image forming apparatus forms a solid white image as an example in which at least no arbitrary image formation is performed at the time of the second transport, and the image is formed on the back surface of the toner image surface even after passing the transfer position. A toner image was not formed.

Specifically, in order to form a solid white image, the irradiation of the scanning light 4 by the laser exposure optical system 3 was stopped so that no latent image was formed, and no image formation was performed.

It is to be noted that the image data may be simply made solid white without stopping the laser exposure optical system 3. Also,
In this embodiment, the solid white image is formed in the mono-color mode (single-color mode) in order to reduce the time.

At the time of the second fixing in the uniform gloss mode, the toner image surface is heated by the ceramic heater 28 located on the opposite side via the transfer material P. For this reason, depending on the type of the transfer material P, heat transfer to the toner image surface is deteriorated, and the amount of heat required for uniform fixing may be insufficient.

In this embodiment, the transfer speed (fixing speed) of the transfer material P at the time of the second fixing in the uniform gloss mode.
Is set to a second transport speed which is lower than the transport speed in the normal mode which is the first operation mode or the transport speed at the time of the first fixing in the uniform gloss mode. Was performed.

Incidentally, besides this method, a ceramic heater
When the transfer material P is transported for the second time in the uniform gloss mode, the fixing film unit
25 may increase the amount of heat applied to the transfer material P compared to the normal mode as the first operation mode or the first transfer of the transfer material P.

Further, by setting the temperature of the ceramic heater 28 high, the temperature of the fixing film 27 during the second transfer of the transfer material P in the uniform gloss mode is set to the first operation mode, the normal mode or the first transfer. The temperature may be higher than the temperature of the fixing film 27 when the material P is transported.

Further, before the transfer of the transfer material P for the second time in the gloss uniform mode, the pressing roller 26 is heated and preheated in advance by performing idle rotation while heating the ceramic heater 28, and the heat is stored to some extent. Then, the transfer material P may be conveyed to fix the toner image to compensate for the shortage of heat from the ceramic heater 28.

In other words, in the second transfer of the transfer material P in the second and third operation modes, the temperature of the pressure roller 26 is set to the normal mode or the temperature of the pressure roller 26 during the first transfer of the transfer material P. It may be performed at a higher height. By using these methods, or by using a plurality of the above methods, heat can be sufficiently supplied to the toner image surface, and the effect in the uniform gloss mode can be enhanced.

As described above, even when the fixing device 21 of the type in which the wait time is shortened is used, when the uniform gloss mode as in this embodiment is executed, the transfer material P once fixed is transferred to the toner image. In order to fix the toner image by transporting it again so that the surface is on the pressure roller 26 side, the toner image surface is leveled, and the gloss (toner) when the gloss of the toner image and the OHP sheet are projected on the screen is projected. (Transparent image)
However, uniform image output became possible.

That is, although the fixing device 21 has a single configuration, it is possible to output an image with a short wait time, and it is also possible to obtain a clear image of the toner image surface, and the OHP sheet is projected on the screen. Brightness when dropped
It is possible to realize an image forming apparatus capable of obtaining an image output with a uniform (light transmission image).

Further, according to the present embodiment, even if a new execution of the uniform gloss mode is added, it is not necessary to particularly add a new device, and the above-mentioned effect can be obtained without increasing the cost. .

In the present embodiment, a film heating type heating device is employed as the fixing device 21 having a short wait time. However, a heating device employing an induction heating method such as magnetic induction heating may be employed. . Similar effects can be obtained when a tandem-type image forming apparatus is employed.

In this embodiment, a film heating type heating device is employed as the fixing device 21 having a short wait time. However, a heating device employing an induction heating method such as magnetic induction heating may be employed. . Similar effects can be obtained when a tandem-type image forming apparatus is employed.

<Second Embodiment> In the present embodiment, even if the image forming apparatus does not have an automatic double-sided mechanism, an image output in which the gloss unevenness of the toner image is improved can be obtained in the same manner as in the above-described embodiment. Glossy uniform mode like (2nd,
Third operation mode) was prepared. The same components as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

In the uniform gloss mode of this embodiment, the toner image surface of the transfer material P is fixed to the fixing film unit 25 side in the same manner as in the normal image formation, and then the toner image surface at the time of conveyance is reversed by the user. Then, the transfer material P is set again on a feeding unit such as the transfer material tray 20.

Thereafter, the user gives an instruction to the image forming apparatus to start the second transfer of the transfer material P in the uniform gloss mode by the transfer start instructing means. In the second transfer of the transfer material P, the toner image surface of the transfer material P is fixed on the pressure roller 26 side having the elastic layer 32 as in the above-described embodiment. And the brightness of an OHP sheet transmitted image can be made uniform.

In the present embodiment, since the user manually sets the transfer material P before the second transport, the user can operate the operation buttons or the operation panel as an operation unit provided in the image forming apparatus on the spot. Is used to instruct the start of the transfer of the transfer material P for the second time.

The instruction to start the second transfer of the transfer material P may be issued from a host computer that can communicate with the image forming apparatus.

As described above, according to this embodiment, by executing the uniform gloss mode as in this embodiment without using the automatic double-sided mechanism, the image can be formed without increasing the cost as in the above-described embodiment. This makes it possible to output images with uniform gloss and brightness (light transmission image) when projecting an OHP sheet.

That is, although a single fixing device 21 is used, an image can be output in a short wait time, and a clear image on the toner image surface can be obtained.
An image forming apparatus capable of equalizing the brightness and the like of a sheet transmitted image was realized.

Further, in the present embodiment, after the first transfer of the transfer material P, the user himself can confirm the finish, and the second transfer of the transfer material P for making the gloss more uniform only when necessary. You can decide to do it.

Also, by preparing a mode (second operation mode) in which only the second transport in the gloss uniform mode can be independently executed, a normal image formation and output in the past can be performed. If uniformity of gloss becomes necessary later, a second transfer of the transfer material P may be additionally performed to change the toner image to a uniform gloss toner image.

In the present embodiment, a film heating type heating device is employed as the fixing device 21 having a short wait time. However, a heating device employing an induction heating method such as magnetic induction heating may be employed. . Similar effects can be obtained when a tandem type image forming apparatus is used.

<Third Embodiment> In this embodiment as well, a uniform gloss mode is prepared so as to obtain an image output with improved gloss unevenness as in the first and second embodiments.
In addition, components configured in the same manner as the above-described embodiments are denoted by the same reference numerals, and description thereof is omitted.

The uniform gloss mode in this embodiment is basically the same as the uniform gloss mode in the first and second embodiments, except that no development is performed when the transfer material P is transported for the second time. I decided that.

Specifically, the developing units 5 to 8 were separated from the photosensitive drum 1. In this embodiment, when the developing devices 5 to 8 are arranged at the developing position by the rotation of the rotary device 14, the developing devices 5 to 8 are selectively brought into contact with the photosensitive drum 1 by operation of a cam or the like (not shown). / Can be separated.

In the normal development, the developing units 5 to 8 are performed in contact with each other. On the other hand, during the second transfer of the transfer material P in the uniform gloss mode in the present embodiment, the developing units 5 to 8 are used.
Since the developing unit 8 does not perform development by transitioning to a state in which the transfer member 8 is separated from the photosensitive drum 1, the toner does not transfer to the photosensitive drum 1 and the toner does not transfer to the back side of the toner image surface of the transfer material P.

As means for separating the photosensitive drum 1 from the developing units 5 to 8, other than the above-described cam mechanism, the developing units 5 to 8 may be shifted from their original developing positions by the revolution of the rotary device 14. A means for separating each of the developing devices 5 to 8 from the photosensitive drum 1 by disposing the developing devices 5 to 8 may be adopted.

After the developing units 5 to 8 are separated from each other, the developing roller 5
Since it is not necessary to drive a to 8a, the driving may be stopped, and the charging of the photosensitive drum 1 by the charging roller 2 and the exposure by the laser exposure optical system 3 may be stopped.

As means for preventing the development, the output of the developing bias voltage applied to the developing rollers 5a to 8a serving as the developing means is stopped, or the developing bias voltage value is set to a set value which cannot be developed. By doing so, development may not be performed.

During normal development, the surface potential of the photosensitive drum 1
(Charging potential; -700 V to exposure section potential; -200 V), the developing bias voltage value applied to the developing rollers 5a to 8a is -300 V to -4, which is intermediate between the charging potential and the exposure section potential.
Although the development was performed at 00 V, during the second transfer of the transfer material P, the developing bias voltage value was further increased toward the positive polarity (0 V
By setting the voltage to -200 V, it is possible to prevent the toner having the negative polarity from transferring to the photosensitive drum 1 and further prevent the toner from transferring to the back side of the toner image surface of the transfer material P.

As described above, according to the present embodiment, the first,
In addition to obtaining the same effects as in the second embodiment, by not performing the development, the unnecessary toner does not reliably transfer to the back side of the toner image surface of the transfer material P.

If the developing devices 5 to 8 are separated from the photosensitive drum 1 during the second transfer of the transfer material P, the operations of the developing devices 5 to 8 can be stopped. Developing device 5
~ 8 and the deterioration of the toner can be minimized.

<Fourth Embodiment> In this embodiment, a uniform gloss mode is prepared so that an image output with improved gloss unevenness and the like can be obtained as in the above-described embodiments. In addition, components configured in the same manner as the above-described embodiments are denoted by the same reference numerals, and description thereof is omitted.

The uniform gloss mode in the present embodiment is basically the same as the uniform gloss mode in the first and second embodiments. However, when the transfer material P is transported for the second time, the primary transfer,
Alternatively, the secondary transfer is not performed.

First, the case where the primary transfer is not performed will be described. In this embodiment, the intermediate transfer belt 9 and the photosensitive drum 1 are separated from each other during the second transfer of the transfer material P in the uniform gloss mode so that the primary transfer is not performed.

More specifically, the direction in which the belt erected portion including the intermediate transfer belt 9, the secondary transfer opposing roller 12, the tension roller 16 and the primary transfer roller 10 is moved away from the photosensitive drum 1 with the drive roller 15 as the central axis ( 1 (in the direction of arrow A in FIG. 1) to separate the primary transfer section where the photosensitive drum 1 and the intermediate transfer belt 9 face each other.

In the image forming apparatus of this embodiment, the transport path of the transfer material P slightly changes with the change of the position of the secondary transfer opposing roller 12, but there is no particular problem. In this embodiment, since the intermediate transfer belt 9 and the photosensitive drum 1 are separated from each other,
The drive of the photosensitive drum 1 may be stopped, and the above-described charging, exposure, and development may be stopped.

Further, even if the intermediate transfer belt 9 and the photosensitive drum 1 are not separated from each other as in the above-described embodiment, the primary transfer bias voltage is not applied to the transfer roller 10 serving as a transfer unit, or a reverse polarity is applied. The primary transfer bias voltage may be applied to prevent the primary transfer from being performed.

Next, a case where the secondary transfer is not performed will be described. In the present embodiment, the intermediate transfer belt 9 and the secondary transfer roller 11 are separated from each other during the second transfer of the transfer material P in the gloss uniform mode so that the secondary transfer is not performed.

Specifically, the secondary transfer roller 11 was separated from the intermediate transfer belt 9 by the operation of a cam or the like (not shown).
In the image forming apparatus of the present embodiment, the transfer material P is separated from the intermediate transfer belt 9 and the secondary transfer roller 11 by the separation of the secondary transfer roller 11.
11 and cannot be transported.
Is set to be shorter than the length of the transfer material P that can be conveyed in the uniform gloss mode in the conveyance direction between the registration roller pair 22 and the fixing nip portion 34 that sandwich the transfer material P. Roller pair 22 or fixing nip
It was always pinched by any of the 34, and could be transported stably.

In the present embodiment, since the intermediate transfer belt 9 is separated from the original conveyance path of the transfer material P by the separation between the intermediate transfer belt 9 and the secondary transfer roller 11, the driving of the intermediate transfer belt 9 and the photosensitive drum 1 is performed. May be stopped, and the above-described charging, exposure, and development may be stopped.

Further, even if the intermediate transfer belt 9 and the secondary transfer roller 11 are not separated as in the above embodiment, no secondary transfer bias voltage is applied to the secondary transfer roller 11, The secondary transfer may not be performed by applying a transfer bias voltage or the like.

As described above, according to the present embodiment, the same effects as those of the first and second embodiments can be obtained, and in addition, since the transfer is not performed, the transfer material P is provided on the back surface of the toner image surface. As a result, no unnecessary toner image is formed.

When the transfer section is separated during the second transfer of the transfer material P, the driving of the photosensitive drum 1 and the charging by the charging roller 2 can be stopped. , The deterioration of the photosensitive drum 1 such as the surface of the photosensitive drum 1 being scraped can be minimized.

Note that the same effect can be obtained when a tandem type image forming apparatus is employed. However, in the case of the direct transfer tandem method (described later), there is no distinction between primary transfer and secondary transfer because the transfer is directly performed from the photosensitive drum 1 to the transfer material P. The transfer can be prevented from being performed in the same manner as described above by separating the transfer or applying no transfer bias.

<Fifth Embodiment> In this embodiment as well, a uniform gloss mode (third operation mode) is prepared so as to obtain an image output with improved gloss unevenness, as in the first and second embodiments. did. In addition, components configured in the same manner as the above-described embodiments are denoted by the same reference numerals, and description thereof is omitted.

The uniform gloss mode in this embodiment is basically the same as the uniform gloss mode in the first and second embodiments, except that the fixing device is used for the first transfer of the transfer material P in the uniform gloss mode. Fixing film unit serving as 21 heating means
Numeral 25 indicates that the amount of heat applied to the toner image surface of the transfer material P is reduced as compared with the normal image formation (first operation mode).

More specifically, during the first transfer of the transfer material P in the uniform gloss mode, the temperature adjustment temperature of the ceramic heater 28 is reduced as compared with the normal image formation to apply the transfer material P to the toner image surface. The calorie was reduced. Alternatively, the amount of heat applied to the toner image surface of the transfer material P may be reduced by increasing the fixing speed.

The normal image formation described here refers to a normal case where the fixing is completed by passing the sheet through the fixing device 21 once and the completed image is obtained. In order to finish fixing once,
It is necessary to apply a sufficient amount of heat to the transfer material P by one fixing, and to secure necessary and sufficient fixing property as a final image.

On the other hand, the first transfer material P in the gloss uniform mode
When the fixing is performed in the same manner as during the normal image formation during the transfer of the transfer material P, even after the second transfer of the transfer material P, which is performed with the toner image surface being on the pressure roller 26 side, the gloss unevenness of the toner image surface is slightly changed. In some cases, it remained. Especially OHP
When the sheet is used as the transfer material P, gloss unevenness is OH
Since the brightness unevenness of the transmitted image of the P sheet is emphasized and appears, there is a case where such gloss unevenness is not acceptable.

The reason why gloss was not completely uniformed even in the second transfer of the transfer material P is considered to be as follows. That is, as described in the conventional example, the first transfer material P
During the transfer, the heat is applied to produce a glossy portion and a non-glossy portion, resulting in uneven gloss. However, if the amount of heat applied at the time of fixing is large, the difference in gloss between the two becomes large, and the second transfer material P The difference could not be completely eliminated by transportation.

Therefore, in the present embodiment, during the first transfer of the transfer material P in the uniform gloss mode, the amount of heat applied to the transfer material P in the fixing unit is reduced by the above-described method or the like, and even in a portion where heat is applied and gloss is generated. The gloss was kept low, and the uneven gloss of the image after the first transfer of the transfer material P was further reduced.

In the uniform gloss mode, since a fixed image is formed by fixing twice, the fixing property after the first transfer of the transfer material P is sufficient to withstand the second transfer and transfer of the transfer material P. is there. That is, it is possible to reduce the amount of heat applied to the transfer material P during the first transfer of the transfer material P.

Hereinafter, a case where an image is formed on an OHP sheet will be described as an example, and a case where the first fixing in the uniform gloss mode is performed in the same manner as a normal image formation, and a case where the first fixing is performed according to the present embodiment. Will be described with specific comparison.

First, the case where the first fixing is performed in the same manner as in normal image formation will be described. In the case of the normal OHP sheet mode in which the fixing is completed once, the fixing speed is 40 mm.
/ sec, the temperature of the ceramic heater 28 was set to 180 ° C., and the first fixing in the gloss mode was performed under the same conditions. At the time of the second fixing operation with the toner image surface facing the pressure roller 26, the fixing speed was 40 mm / sec and the temperature of the ceramic heater 28 was 210 ° C.

The toner image at the end of the first fixing is
When viewed as a transmission image of the HP sheet, a bright portion and a dark portion were formed in some places, and the whole was non-uniform.
In the image after the completion of the second fixing, although the brightness became considerably uniform, it was confirmed that the unevenness created in the first fixing did not disappear and remained.

Next, a case where the first fixing is performed according to this embodiment will be described. According to the present embodiment, during the first transfer of the transfer material P in the gloss uniform mode for the OHP sheet, the amount of heat applied to the OHP sheet is reduced by setting the fixing speed to 60 mm / sec and the temperature of the ceramic heater 28 to 150 ° C.

At the time of the second fixing in which the toner image surface of the transfer material P is set to the pressure roller 26 side, the fixing speed is set to 40 mm as described above.
/ sec and the temperature of the ceramic heater 28 was 210 ° C.

Although the toner image at the time after the first fixing was not glossy as a whole and was entirely dark even when projected as an OHP sheet, unevenness in gloss and brightness unevenness in the transmitted image appeared strongly. And had a fixing property capable of withstanding the second transport. Subsequently, after performing the second fixing, uniform gloss was given as a whole, and the transmitted image of the OHP sheet was also uniform and bright.

As described above, according to the present embodiment, the amount of heat applied to the transfer material P in the fixing unit at the time of the first transfer of the transfer material P in the uniform gloss mode is reduced.
Of the toner image surface can be kept to such an extent that there is no overall gloss and unevenness is not conspicuous, and the uniformity of gloss of the image after the second fixing is continuously performed. . That is, the effects of the first and second embodiments can be further enhanced.

In addition to the image forming apparatus shown in FIG. 1, the photosensitive drum 1, developing units 5 to 8, laser exposure optical system 3
There is known a so-called tandem type color image forming apparatus in which an image forming station capable of developing a single color toner image is prepared independently for each color.

Also in the tandem system, the image forming stations for each color are arranged on the circumference of the intermediate transfer belt 9, and the intermediate transfer belt 9 passes through each image forming station, so that the toner image of each color is primarily transferred. To form a full-color image on the intermediate transfer belt 9,
Each image forming station is arranged on the transfer path of the transfer material P without using the next transfer method (intermediate transfer tandem method) or the intermediate transfer belt 9, and the image forming units of each color are sequentially transferred during transfer of the transfer material P. A method of forming a full-color image by passing the image (direct transfer tandem method) is known.

Some image forming apparatuses are capable of forming images on both sides of the transfer material P, and are capable of forming images on both sides. In order to form images on both sides, it is necessary to turn over the transfer material P on which image formation has been completed on one side once and then feed it again. When an automatic double-sided conveyance device is provided and this is performed automatically (automatic double-sided), the user sets the transfer material P on which the image has been formed once on the feeding tray or the like again so that the surface at the time of conveyance is reversed. (Manual both sides).

The same effects can be obtained by configuring the above-described various image forming apparatuses in the same manner as in the above-described embodiments.

[0138]

Since the present invention has the above-described structure and operation, even if a fixing means of a type having a reduced wait time is employed, the transfer material once fixed is pressed against the toner image surface. The image forming apparatus prepares and executes a uniform gloss mode in which the sheet is conveyed again to the image forming side and performs fixing, so that the toner image surface is leveled, and the gloss and O
It is possible to output an image with uniform brightness (light transmission image) projected on the screen when projecting the HP sheet.

That is, it is possible to output an image with a short wait time even though the fixing means has a single structure, and it is possible to obtain a clear image on the surface of the toner image, and the image is projected on the screen when the OHP sheet is projected. It is possible to realize an image forming apparatus capable of obtaining an image output with uniform brightness (light transmission image).

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional explanatory view showing a configuration of an image forming apparatus according to the present invention.

FIG. 2 is a schematic cross-sectional explanatory view showing a state in which a toner image surface formed on a transfer material is conveyed with a heating unit side in a fixing unit.

FIG. 3 is a schematic cross-sectional explanatory view showing a state in which the toner image surface formed on the transfer material is conveyed with the fixing unit facing the pressing unit.

FIG. 4 is a diagram illustrating a conventional example.

FIG. 5 is a diagram illustrating a conventional example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Photoreceptor drum, 2 ... Charging roller, 3 ... Laser exposure optical system, 4 ... Scanning light, 5 ... Black developing device, 6 ... Magenta developing device, 7 ... Cyan developing device, 8 ... Yellow developing device, 5
a to 8a: developing roller, 9: intermediate transfer belt, 10: transfer roller, 11: secondary transfer roller, 12: secondary transfer facing roller, 13: cleaning device, 14: rotary device, 15 ...
Drive roller, 16: tension roller, 17: cleaning device, 18: transfer material cassette, 19: bias power supply, 20 ...
Transfer material tray, 21: fixing device, 22: registration roller pair,
23, 24 ... feed roller, 25 ... fixing film unit, 26 ...
Pressure roller, 27 fixing film, 28 ceramic heater, 29 thermistor, 30 film guide, 31 cored bar,
32: elastic layer, 33: coat layer, 34: fixing nip portion, 35: unfixed toner image, 35 ': fixed toner image, P: transfer material

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G03G 15/08 506 G03G 15/08 506A 2H073 507 15/16 103 2H077 15/16 103 21/00 350 2H200 21 / 00 350 H05B 3/00 310C 3K058 21/14 310E H05B 3/00 310 335 G03G 15/08 507H 335 21/00 372 F-term (reference) 2H027 DA12 DC02 EA12 ED02 ED08 ED09 ED24 ED25 EE01 EJ15 FA13 FA30 GA31 2 BB00 2H033 AA06 AA45 AA46 BA25 BA26 BB29 BB30 BE03 CA04 CA07 CA13 CA16 CA27 CA36 CA44 2H035 CA07 CB01 CG01 2H071 CA02 DA15 DA26 DA31 2H073 AA01 BA01 BA09 BA13 2H077 AD35 BA03 BA07 GA08 GB23 GA26 GA06 JA02 JA28 JA29 JC04 LA24 NA01 PA02 PA1 0 PA15 PA26 3K058 AA02 BA18 CA12 CA61 CA91 DA01 DA21 GA06

Claims (32)

[Claims] 1. An image forming apparatus comprising: an image forming unit for forming a toner image on a transfer material; and a fixing unit for fixing the toner image on the transfer material, wherein the fixing unit includes at least a heating unit, Pressurizing means opposed to the heating means through the heating means, wherein the heating means has an elastic layer having a thickness of 0 or more and 500 μm or less between the heat generating portion and the surface of the heating means, The means has an elastic layer having a thickness of 500 μm or more, wherein the image forming apparatus forms a toner image on a transfer material,
A first operation mode in which the toner image surface of the transfer material is fixed to the heating means side to form a completed image, and the transfer material output in the first operation mode is fixed in the first operation mode. And a second operation mode in which the transfer material is conveyed so that the toner image surface is set to the pressure unit side and passes through the fixing unit again. In the second operation mode,
An image forming apparatus which does not perform at least any image formation. 2. An image forming apparatus comprising: an image forming unit for forming a toner image on a transfer material; and a fixing unit for fixing the toner image on the transfer material, wherein the fixing unit includes at least a heating unit; Pressurizing means opposed to the heating means through the heating means, wherein the heating means has an elastic layer having a thickness of 0 or more and 500 μm or less between the heat generating portion and the surface of the heating means, The means has an elastic layer having a thickness of 500 μm or more, and the image forming apparatus forms a toner image on the transfer material by the first transfer of the transfer material, and places the toner image surface of the transfer material on the heating unit side. After fixing the image, the same transfer material
A third operation mode is provided in which the transfer material is conveyed a second time so that the toner image surface fixed in the second conveyance is passed through the fixing device again with the toner image surface fixed to the pressure unit side, and a completed image is obtained. The image forming apparatus is characterized in that at least no arbitrary image formation is performed during the second transport. 3. A toner image is formed on a transfer material, and the image is fixed with the toner image surface of the transfer material facing the heating means.
The image forming apparatus according to claim 2, further comprising a first operation mode for setting a completed image. 4. The method according to claim 1, wherein the amount of heat applied to the transfer material by the heating means during the first transfer of the transfer material in the third operation mode is smaller than that in the first operation mode. The image forming apparatus according to claim 3. 5. The apparatus according to claim 3, wherein the temperature of said heating means is made lower than the temperature in said first operation mode during the first transfer of the transfer material in said third operation mode. The image forming apparatus according to claim 4. 6. A fixing device according to claim 3, wherein a fixing speed of said fixing unit is set higher than a fixing speed of said fixing unit in said first operation mode during the first transfer of the transfer material in said third operation mode. The image forming apparatus according to any one of claims 3 to 5, wherein: 7. The amount of heat applied by the heating means to the transfer material at the time of the second transfer of the transfer material in the second operation mode or the third operation mode may be the same as that in the first operation mode or in the first operation mode. The image forming apparatus according to any one of claims 1 to 6, wherein the number of the transfer members is increased from that at the time of transporting the transfer material for the first time. 8. The method according to claim 1, wherein the fixing speed of the fixing unit during the second transfer of the transfer material in the second operation mode or the third operation mode is set to the first operation mode or the first transfer of the transfer material. 2. The fixing device according to claim 1, wherein the fixing speed is lower than a fixing speed of the fixing unit.
The image forming apparatus according to any one of claims 1 to 7. 9. The temperature of the heating means during the second transfer of the transfer material in the second operation mode or the third operation mode is set to the temperature in the first operation mode or the first transfer of the transfer material. The image forming apparatus according to claim 1, wherein a temperature of the image forming apparatus is higher than a temperature of the heating unit. 10. The second operation mode or the third operation mode.
The second transfer of the transfer material in the operation mode is performed by setting the temperature of the pressurizing unit higher than the temperature of the pressurizing unit in the first operation mode or the first transfer of the transfer material. The image forming apparatus according to claim 1, wherein: 11. The second operation mode or the third operation mode.
Prior to the second transfer of the transfer material in the operation mode of
The image forming apparatus according to claim 10, wherein the pressurizing unit is preheated. 12. The second operation mode or the third operation mode.
12. The image forming apparatus according to claim 1, wherein a solid white image is formed during the second transfer of the transfer material in the operation mode. 13. The image forming apparatus according to claim 12, wherein the solid white image is formed in a mono color mode. 14. The second operation mode or the third operation mode.
The image forming apparatus according to claim 1, wherein image forming is not performed during the second transfer of the transfer material in the operation mode. 15. The method according to claim 2, further comprising an automatic double-sided conveying means, wherein the automatic transfer from the first transfer of the transfer material to the second transfer of the transfer material in the third operation mode is performed. The image forming apparatus according to claim 1. 16. The first operation mode or the third operation mode.
After the transfer material having completed the first transfer in the operation mode is set in the transfer material supply unit of the apparatus, the transfer of the second transfer material in the second operation mode or the third operation mode is started. 2. The method according to claim 1, wherein:
6. The image forming apparatus according to any one of 5. 17. The method according to claim 17, wherein the second operation mode or the third operation mode is selected.
A transfer start instructing means capable of instructing a second transfer start in the operation mode of (1).
7. The image forming apparatus according to claim 6. 18. The method according to claim 18, wherein the second operation mode or the third operation mode is selected.
The instruction for starting the second transfer in the operation mode of (1) is performed by an operation unit provided in the apparatus.
8. The image forming apparatus according to 7. 19. The second operation mode or the third operation mode.
18. The image forming apparatus according to claim 17, wherein the instruction to start the second transfer in the operation mode is performed on a host computer capable of communicating with the apparatus. 20. The image forming apparatus according to claim 1, wherein the heating unit includes a heater inside a film. 21. The image forming apparatus according to claim 1, wherein said heating means uses magnetic induction heating. 22. The image forming apparatus according to claim 1, wherein the pressing unit is a pressing roller. 23. A developing device for supplying a toner, an image carrier for carrying a toner image, a developing means for forming a toner image on the image carrier, and a developing device for forming a toner image on the image carrier. 23. A transfer means for transferring onto a transfer material, comprising:
Item 10. The image forming apparatus according to item 1. 24. A developing device for supplying a toner, an image carrier for carrying a toner image, a developing means for forming a toner image on the image carrier, and a toner image formed on the image carrier. An intermediate transfer body to be primarily transferred; a primary transfer unit for primarily transferring a toner image formed on the image carrier to the intermediate transfer body; and a toner image transferred to the intermediate transfer body. 23. A secondary transfer means for performing secondary transfer on a transfer material, further comprising:
Item 10. The image forming apparatus according to item 1. 25. The second operation mode or the third operation mode.
25. The image forming apparatus according to claim 23, wherein development is not performed during the second transport in the operation mode. 26. The second operation mode or the third operation mode.
26. The image forming apparatus according to claim 25, wherein the developing unit is separated from the image carrier during the second transport in the operation mode. 27. The second operation mode or the third operation mode
26. The method according to claim 25, wherein the output of the developing bias voltage applied to the developing unit is stopped or the developing bias voltage value is set to a non-developable value during the second transport in the operation mode. 27. The image forming apparatus according to 26. 28. The second operation mode or the third operation mode
28. The image forming apparatus according to claim 26, wherein the driving of the developing unit is stopped during the second transport in the operation mode. 29. The second operation mode or the third operation mode
The image forming apparatus according to any one of claims 23 to 28, wherein transfer is not performed at the time of the second transport in the operation mode of (1). 30. The second operation mode or the third operation mode.
30. The image forming apparatus according to claim 29, wherein the transfer unit is separated at the time of the second transport in the operation mode. 31. The second operation mode or the third operation mode.
30. The transfer bias voltage applied to the transfer unit is stopped or the transfer bias voltage value is set to a non-transferable value during the second transfer in the operation mode. 30. The image forming apparatus according to 30. 32. The second operation mode or the third operation mode.
32. The image forming apparatus according to claim 30, wherein the driving of the image carrier is stopped during the second transport in the operation mode.