JP2971648B2 - Image forming device - Google Patents

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 used for a recording device such as a printer or a copying machine.

[0002]

2. Description of the Related Art Conventionally, when an image is formed in a recording apparatus such as a printer or a copying machine, an electrophotographic recording method based on the Carlson method is generally employed. In this case, the electrostatic latent image carrier is charged, exposed, and developed to form a toner image on the electrostatic latent image carrier. Then, recording paper such as paper is superimposed on the toner image on the electrostatic latent image carrier to transfer the toner image, and then the toner remaining on the surface of the recording paper is cleaned by a cleaning device. As described above, image formation in the conventional image forming apparatus is performed by six processes.

In the transfer process of the above-described image forming apparatus, a toner image is transferred to a recording sheet by using an electrostatic force. However, this transfer method has low transfer efficiency and requires not only a cleaning device for cleaning the toner remaining on the electrostatic latent image carrier after the transfer, but also a maintenance operation for discarding the collected toner. Becomes And
Since the toner is a powder, the toner is easily scattered, and contaminates the body and clothes of the operator, and scatters inside and outside the image forming apparatus.

Therefore, there is provided an image forming apparatus which does not require a cleaning device and does not need to dispose of collected toner. FIG. 2 is a schematic configuration diagram of a conventional image forming apparatus. In the drawing, reference numeral 101 denotes an electrostatic latent image carrier formed in a drum shape, which is formed by providing a photoconductive layer on a conductive support, and which is rotated at a constant peripheral speed in a direction indicated by an arrow E by a motor (not shown). Let me do. Reference numeral 102 denotes an endless developing object, and the electrostatic latent image carrier 101 and the pressure roller 1
It is stretched between 03.

Reference numeral 104 denotes a charging device, which is provided so as to face the surface of the electrostatic latent image carrier 101. Reference numeral 105 denotes an exposure device, which converts an image signal into light to carry the electrostatic latent image. The body 101 is irradiated. Reference numeral 106 denotes a developing device, which adsorbs the toner 108 onto the toner carrier 107 and conveys the toner 108 in the direction of arrow D in the drawing, and closely adheres to cover the electrostatic latent image formed on the electrostatic latent image carrier 101. Then, the object to be developed 102 which has been superposed is developed.

An A 109 is provided to prevent the toner image formed on the developing member 102 from scattering when the developing member 102 is separated from the electrostatic latent image carrier 101.
C corona discharger. 110 is the pressure roller 103
And a heating roller provided in pressure contact with the heating roller. The heating roller 110 is formed by providing a heating lamp, for example, a halogen lamp, inside a hollow sleeve.

Next, the operation and operation of the image forming apparatus having the above configuration will be described. When the electrostatic latent image carrier 101 rotates at a constant peripheral speed in a direction indicated by arrow E by a motor (not shown) and the pressure roller 103 also rotates in the same direction, the developing member 102 The vehicle starts running due to frictional force and moves in the direction indicated by arrow F in the figure. At this time, a tension mechanism (not shown) attached to the pulling roller 111 operates to apply an appropriate tension to the developing member 102, and moves the developing member 102 at the same speed as the electrostatic latent image carrier 101. At the same time, power is supplied to the heating roller 110, and heating is started.

Next, in the charging process, the electrostatic latent image carrier 101 is charged uniformly and uniformly by the charging device 104. The developing object 102 is configured to be in close contact with the electrostatic latent image carrier 101 between the charging process and the developing process. In the subsequent exposure process, light corresponding to the image signal is generated by the exposure device 105, passes through the developing object 102, and irradiates the electrostatic latent image carrier 101 to form an electrostatic latent image.

In the developing process, the developing device 10
By 6, development is performed on the development target 102 that is closely attached to the electrostatic latent image support 101. Here, in the space between the toner carrier 107 and the developing member 102, lines of electric force associated with the electrostatic latent image formed on the electrostatic latent image holding member 101 penetrate the developing member 102. For this reason, the charged toner 108 on the toner carrier 107 adheres and develops on the developing member 102 by electrostatic force, and a toner image is formed. The developing object 102 on which the toner image is formed
Are separated from the electrostatic latent image carrier 101 after being developed.
At this time, the electric charge on the surface is removed by the AC corona discharger 109, and the disturbance of the toner image on the developing member 102 which occurs when the toner image is separated from the electrostatic latent image carrier 101 can be prevented.

Thereafter, the developing object 102 separated from the electrostatic latent image carrier 101 is conveyed to a transfer / fixing unit constituted by a pressure roller 103 and a heating roller 110. Here, the recording paper 114 stored in the paper cassette 113 is taken out of the paper cassette 113 by the paper feeding roller 115 and sent to the stopped paper feeding roller 116, where the skew of the recording paper 114 is corrected.

Then, the paper feed roller 116 is started again,
The recording paper 114 is sent to a transfer / fixing unit. The developing member 102 on which the toner image is formed and the recording paper 114 are superposed here, and are heated and pressed. At this time, the surface of the heating roller 110 has already reached the temperature required for transfer and fixing, and is maintained at that temperature.
The toner 108 on the object to be developed 102 is melted through the medium 14 and penetrated between the fibers of the recording paper 114 by a pressurizing action. The transferred and fixed recording paper 114 is sent to the outside of the image forming apparatus by a paper discharge roller 117.

On the other hand, the developed body 1 after being transferred and fixed
02 may leave a small amount of toner 108,
The remaining toner 108 is applied to the fixing cleaner 11 provided on the pressure roller 103 so as to press the developing object 102 in pressure.
8 removed. At this time, the toner 108 is transferred and
Since the fused state in the fixing section continues, it can be easily removed.

Further, the electrostatic latent image carrier 101 is separated from the developing object 102 after the developing process, and
Thus, the entire surface is irradiated with light, and the residual charges on the surface are removed. Thus, the electrostatic latent image carrier 101 is repeatedly used. As described above, the electrostatic latent image carrier 101 and the developing object 102 are provided so as to be partially in close contact with each other, and the developing object 10 in close contact with the electrostatic latent image carrier 101 on which the electrostatic latent image is formed.
2, a recording paper 114 is superimposed on the toner image on the developing member 102, and the toner image is transferred to the recording paper 114 and fixed.

In the transfer / fixing process, heating and pressurizing are performed, and the toner 108 on the developing object 102 is transferred and fixed to the recording paper 114, and the transferred developing object 102 is transferred.
Even if the toner 108 remains on the toner,
8 can be easily wiped off with a pad such as a felt constituting the fixing cleaner 118 while the melt 8 is being melted. At this time, since the toner 108 has changed from powder to semi-liquid, it does not scatter. Therefore, toner 1
The process of cleaning 08 becomes unnecessary. Also,
Fixing can be performed at the same time as transfer, so that an independent fixing device is not required, and the number of processes can be reduced.

Therefore, it is possible to prevent contamination of the operator's body and clothing and scattering of the toner 108 into and out of the image forming apparatus during the disposal work of the toner 108, thereby improving maintainability. Moreover, since the number of processes can be reduced, the size and cost of the image forming apparatus can be reduced. FIG. 3 is a time chart showing a recording sequence of the conventional image forming apparatus.

When a recording start signal is output, power supply to the heating roller 110 is started, and at the same time, the electrostatic latent image carrier 101 and the pressure roller 103 rotate to start the traveling of the developing object 102. .

[0017]

However, in the above-described conventional image forming apparatus, if the image formation is continuously performed, the recorded image may not be stable. That is,
Compared with a normal image, the toner adheres to a white portion, which is a non-image portion, causing a background fog, and an increase or decrease in recording density, resulting in image deterioration.

When the cause of the instability of the image was examined, it was found that the main cause was that the developing member 102 was charged. Thus, the relationship between the image deterioration and the charging of the developing object 102 will be described. That is, the adhesion of the toner 108 to the developing object 102 in the developing process is controlled by the electric field strength between the electrostatic latent image formed on the developing object 102 and the toner carrier 107 and the electrostatic force acting on the charged toner 108. Is done. In this case, the electric field is
02, the electric field intensity changes if the developing object 102 is charged. Therefore, the adhesion of the toner 108 to the developing object 102 also changes, and the image deteriorates. The developing object 102 is very easily charged particularly in a transfer process. This is because the heating roller 110 and the pressure roller 103 are in a pressurized state, and the pressure applied to the developing object 102 is larger than when the roller 102 comes into contact with another roller or the like.

The present invention solves the above-mentioned problems of the conventional image forming apparatus, and develops a developing object closely adhered to an electrostatic latent image carrier on which an electrostatic latent image is formed. Overlapping the recording medium with the object to be developed, pressurizing and heating to prevent electrification generated when transferring the toner image on the object to the recording paper, and to form an image capable of obtaining a long-term stable image. It is intended to provide a device.

[0020]

For this purpose, in the image forming apparatus of the present invention, an electrostatic latent image carrier, a charging device for charging the surface of the electrostatic latent image carrier, and the electrostatic latent image An exposure device that exposes the carrier to form an electrostatic latent image; a developing body that is in close contact with and overlaps the electrostatic latent image carrier on which the electrostatic latent image has been formed; In response to the electrostatic latent image,
The image forming apparatus has a developing device that develops the developing object to form a toner image.

A transfer / fixing section comprising a heating element and a pressure roller is provided. The transfer and fixing are performed by pressing and heating the recording medium with the developing member on which the toner image is formed, and heating. At the same time. The heating element is heated and maintained at a set temperature required for fixing. The developing object is on standby until the heating element reaches the set temperature, and starts to run after reaching the set temperature.

In the case where support means for selectively setting the heating element and the pressure roller in the released state and the pressure state is provided, the heating element and the pressure roller are maintained until the heating element reaches a set temperature. In a release state, and a switching means for switching to a pressurized state after reaching a set temperature.

[0023]

According to the present invention, as described above, the surface of the electrostatic latent image carrier is charged by the charging device and then exposed by the exposure device to form an electrostatic latent image. The object to be developed is superimposed on the electrostatic latent image carrier on which the electrostatic latent image has been formed, and the developing device moves the object to be developed according to the electrostatic latent image on the electrostatic latent image carrier. Develop to form a toner image.

The developing member on which the toner image is formed is sent to a transfer / fixing section composed of a heating element and a pressure roller, and is superposed on a recording paper, pressed and heated. The toner image is melted by heating, penetrates the recording paper by pressure, and transfer and fixing are performed simultaneously. The heating element is heated and maintained at a set temperature required for fixing. The developing object is on standby until the heating element reaches the set temperature, and starts to run after reaching the set temperature. In the transfer / fixing section, when the developing body is pressed by the heating body and the pressure roller, the developing body is charged. However, when the developing body moves to the transfer / fixing section, the heating body is set at the set temperature. , The heat carrier generated inside the developing member neutralizes the charge generated by the charging.

In the case where support means for selectively setting the heating element and the pressure roller in the released state and the pressure state is provided, the heating element and the pressure roller are maintained until the heating element reaches a set temperature. In a release state, and a switching means for switching to a pressurized state after reaching a set temperature. In this case, the developing body is not pressed by the heating body and the pressure roller until the heating body reaches the set temperature, so that the developing body is not charged. When the object to be developed is pressurized, the heating element has reached the set temperature, so that even if the object to be developed is charged, the charge is neutralized by the heat carrier.

[0026]

Embodiments of the present invention will be described below in detail with reference to the drawings. As described above, when an image is repeatedly formed using a conventional image forming apparatus, the instability of the image is caused by charging on the developing object 102 (see FIG. 2). The charge amount of the developing object 102 is not constant but fluctuates greatly. This is because the cause of charging is an electrostatic phenomenon, and is largely governed by the environment and the like. Therefore, when the charge amount is small, a stable image similar to that of normal recording is formed. On the other hand, when the charge amount is large, a ground fog occurs, and the recording density increases or decreases. Is not stable.

Here, since the film used for the developing object 102 has an insulating property, the film is charged by coming into contact with various objects, that is, rollers, which are the traveling paths of the developing object 102. The developing object 102 is charged particularly in a transfer process. This is because the heating roller 110 and the pressure roller 103 are placed in a pressurized state, and the pressure applied to the developing object 102 is larger than that in the case of contact with another roller or the like.

Further, it can be seen that the charging of the developing member 102 in the transfer / fixing portion is remarkable at the start of recording. In a normal recording sequence, when recording is started and the developing object 102 travels, the surface of the developing object 102 is gradually charged, and reaches a peak value after a certain period of time. Thereafter, the charge amount gradually decreases. Therefore, the stability of image formation is poor at the start of recording, and the image formation gradually returns to a normal stable state.

Therefore, the recording sequence was set as follows, and the charge amount of the developing member 102 was measured in the same manner. That is, first, the power supply to the heating roller 110 is stopped and the developing object 102 is caused to run. In this case, the developing object 102
The charge amount gradually increases as in a normal recording sequence, and does not attenuate thereafter. Next, power is supplied to the heating roller 110 before traveling on the object to be developed 102, and the object to be developed 102 is caused to travel after the surface temperature has sufficiently reached a temperature necessary for transfer. In this case, the developing object 102 is not charged.

From the above, the object to be developed 102 is transferred and transferred.
By being pressed by the fixing unit, the heating roller 110 and the pressure roller 103 come into strong contact with each other and are charged.
When the temperature required to transfer and fix the toner 108 on the recording paper 114 has been reached, heat carriers are generated inside the object to be developed 102 to neutralize the charge on the surface and eliminate the charge. Conceivable.

The heat roller 110 has a large heat capacity to keep its surface temperature constant and to increase its strength. Therefore, after the power supply is started, it takes some time for the heating roller 110 to reach the temperature required for transfer. On the other hand, the developing object 10
2 is started at the same time when the power is supplied to the heating roller 110, so that the pressure of the developing object 102 is started before the heating roller 110 reaches the temperature required for transfer. Therefore, the developing object 102 does not reach the temperature required for transfer, and is charged. When the charge amount of the developing object 102 reaches a peak, the charge gradually decreases.

FIG. 4 is a time chart showing a recording sequence of the image forming apparatus according to the first embodiment of the present invention.
When the recording start signal is output, the heating roller 110
Power supply to the developing device 102 (see FIG. 2) is started, but at this time, the running of the developing object 102 is not started. When the surface temperature of the heating roller 110 reaches a set temperature required for transfer, a temperature reaching signal is output, and the electrostatic latent image carrier 101 is output.
Then, the motor (not shown) of the pressure roller 103 rotates, and the running of the developing object 102 is started.

FIG. 1 is a schematic structural view of the image forming apparatus of the present invention. In the figure, reference numeral 101 denotes an electrostatic latent image carrier formed in a drum shape, which is formed by providing a photoconductive layer 101b on a conductive support 101a.
Any of organic photoconductors, zinc oxide photoconductors, and amorphous silicon photoconductors can be used. The electrostatic latent image carrier 101 is rotated at a constant peripheral speed in a direction indicated by an arrow E by a motor (not shown) together with a pressure roller 133 described later.

Reference numeral 102 denotes an endless developing object, which includes an electrostatic latent image carrier 101 and a heating element 13 as one transfer means.
1. Rolling rollers 132a, 132b and pulling roller 11
It is stretched between one. Developed object 102 used here
Is heated by the heating element 131 in the transfer / fixing process and reaches around 160 ° C. Therefore, the material must have some heat resistance and insulation properties. In consideration of these, a film using a material such as polyester, polyimide, polyetherimide, polyethersulfone, or polyetheretherketone can be used.
In consideration of electric lines of force generated between the developing member 102 and the toner carrier 107 during development, the thickness of the film is 1
It is preferable that the thickness is not more than 00 μm and not less than 5 μm in consideration of tensile strength and handleability. In this embodiment,
A polyimide film is coated with a fluororesin having excellent release properties and used.

Reference numeral 104 denotes a charging device, which is provided to face the surface of the electrostatic latent image carrier 101, and a corona charger as shown in the figure is generally used. can do. The charging roller is formed by laminating a conductive rubber on a metal core, for example.
An exposure device 105 converts an image signal into light and irradiates the image onto the electrostatic latent image carrier 101. The exposure device 105 has L
In addition to the combination of the ED array and the SELFOC lens (product name), the combination of a laser and an image forming optical system, and the optical system that is generally used in copying machines and projects the reflected light of an original, etc. Can be used.

Reference numeral 106 denotes a developing device, and the toner carrier 1
07 is transported in the direction of arrow D in the drawing, and the toner 108 is developed on the developing object 102 closely stacked so as to cover the electrostatic latent image formed on the electrostatic latent image carrier 101. I do. Further, as the developing device 106, any one of a two-component magnetic brush developing device, a one-component magnetic brush developing device, and a one-component non-magnetic developing device can be used.

Reference numeral 130 denotes a light neutralizing lamp provided for removing the charge as an electrostatic latent image on the electrostatic latent image carrier 101 after development, and 109 denotes an AC corona discharge for removing the charge of the developing object 102. Electrical appliances. The transfer device includes a heating member 131 as one transfer unit and a pressure roller 133 as the other transfer unit, and both are pressed by a certain pressure by a pressing unit (not shown). The heating body 131
Is a roller-shaped member having a metal hollow member and a built-in halogen lamp. In addition, the heating body 131 may be a non-rotating type, and may be configured by a belt-like body. In this case, the heating element 131 is made of Ni-
It has a heating resistance layer composed of P, etc.
It has a protective layer of a ₂ O ₅ , fluororesin or the like. Also,
The pressure roller 133 is formed by laminating rubber on a metal core, and silicone is used as rubber.

Next, the operation and operation of the image forming apparatus will be described with reference to FIGS. FIG. 5 is a block diagram of a power supply control device in the image forming apparatus of the present invention, and FIG.
FIG. 7 illustrates a charging process in the image forming apparatus of the present invention, FIG. 7 illustrates an exposure process in the image forming apparatus of the present invention, FIG. 8 illustrates a developing process in the image forming apparatus of the present invention, and FIG. FIG. 10 is a diagram showing a photo-elimination process in the image forming apparatus of the present invention, FIG. 10 is a state diagram of a separation unit in the image forming apparatus of the present invention, and FIG. 11 is a view showing a transfer / fixing process in the image forming apparatus of the present invention.

In FIG. 5, 131 is a heating element, 151 is a temperature detecting sensor which is disposed near the heating element 131 and detects the surface temperature of the heating element 131, 152 is a temperature setting circuit, and 153 is a temperature detecting sensor 151. A comparator that compares the temperature detected by the comparator with the temperature set by the temperature setting circuit 152.
54 is a heating element 131 based on the output from the comparator 153.
Is a power supply control circuit that turns on and off the power supply.

When the start button of the image forming apparatus is pressed, power supply to the heating element 131 is first started. Heating body 1
The temperature of the surface of the heating element 131 is detected by a temperature detection sensor 151 provided in the vicinity of the heating element 31, and is compared with a set temperature to control power supply to the heating element 131. Therefore, when the heating element 131 reaches the set temperature, the power supply is turned on / off. Then, when the surface temperature of the heating body 131 reaches a certain temperature, a recording start signal is output,
Electrostatic latent image carrier 101 and pressure roller 133 (FIG. 1)
However, the motor starts rotating at a constant peripheral speed by a motor (not shown). As a result, the object to be developed 102 becomes the electrostatic latent image carrier 1
The electrostatic latent image carrier 101 moves at the same speed as the electrostatic latent image carrier 101 in a direction indicated by an arrow F in FIG. First, the charging device 104 is connected to the conductive support 101a.
Latent image carrier 10 having photoconductive layer 101b formed thereon
1 (FIG. 6).

In the exposure process (FIG. 7), the exposure apparatus 10
Light corresponding to the image signal is generated by 5 and irradiated on the electrostatic latent image carrier 101 to form an electrostatic latent image. In this case, light is applied to a portion corresponding to an image on the electrostatic latent image carrier 101, that is, an image portion, and the charge in the image portion is erased. On the other hand, the charge in the non-image portion is left as it is. In the developing process (FIG. 8), development is performed by a developing device 106 (FIG. 1) provided in contact with or in close proximity to the developing object 102 that is in close contact with the electrostatic latent image carrier 101. In this embodiment, reverse potential development is performed, and a bias potential applying means 112 is provided so that a bias potential is applied between the conductive support 101a of the electrostatic latent image carrier 101 and the toner carrier 107. In such a configuration, the lines of electric force corresponding to the electrostatic latent image formed on the electrostatic latent image holding member 101 are provided in the space between the toner holding member 107 and the developing member 102. Occurs. For this reason, the charged toner 108 on the toner carrier 107 adheres and develops on the developing member 102 by electrostatic force, and a toner image is formed.

After the toner image is formed on the developing object 102, the light generated by the light discharging lamp 130 is
To reach the electrostatic latent image carrier 101, and the charge thereon is removed (FIG. 9). In this case, the electrostatic latent image carrier 1
The electric charge remaining in the non-image area on the area 01 to which the toner 108 does not adhere is completely removed without being blocked by the toner 108. Also, toner 1
The image portion to which 08 has adhered has already been discharged by the exposure device 105 (FIG. 1) in the exposure process, and no charge remains. As described above, since no electric charge remains on the electrostatic latent image carrier 101, when positive and negative electric charges are radiated to the developing object 102 by the AC corona discharger 109 in the separation unit, the electrostatic latent image The charge of the image carrier 101 does not transfer to the developing object 102 (FIG. 10)
.

On the other hand, the recording support housed in the paper cassette 113, ie, the recording paper 114,
The sheet is taken out of the paper cassette 113 by (FIG. 1) and sent to the paper feed roller 116 whose rotation is stopped, where the skew of the recording paper 114 is corrected. Thereafter, the paper feed roller 116 is activated, and the recording paper 114 is sent to the transfer / fixing unit, where the developing material 102 on which the toner image is formed and the recording paper 11 are formed.
4 are stacked here, and the heating body 131 and the pressure roller 133
Heated and pressurized. And the heating element 131
Heat melts the toner 108 on the developing object 102 via the recording paper 114, and the toner 108 penetrates between the fibers of the recording paper 114 by a pressurizing action, so that the transfer to the recording paper 114 and fixing are performed simultaneously. (FIG. 11). The recording paper 114 transferred and fixed in this way is sent out of the image forming apparatus by the paper discharge roller 117, and is stacked on a stacker (not shown).

On the other hand, the developing object 102 after the transfer and fixing is
Since the surface is coated with a fluororesin and has good releasability, the toner 108 hardly remains.
Therefore, an afterimage does not occur on the recording paper 114 in the next process. In the transfer / fixing section, the developing object 10
2 contacts the heating body 131 and the pressure roller 133 with a strong pressing force, and the developing body 102 is charged. However, before the developing body 102 moves to the transfer / fixing section, the temperature of the heating body 131 Since the required temperature has been reached, the
Thermal carriers are generated inside the battery 2, the charges generated by this contact are neutralized, and the charges are eliminated. Therefore, the developing object 1
02 is suppressed low, and a stable image is formed.

In the above embodiment, the power supply to the heating element 131 is performed together with the output of the recording start signal. , And the recording standby state can be set. In that case, the start of the first recording can be made earlier. Next, a second embodiment of the image forming apparatus of the present invention will be described.

FIG. 12 is a time chart showing a recording sequence of the image forming apparatus according to the second embodiment of the present invention. In the above embodiment, the pressure between the heating element 131 and the pressure roller 133 is always set to a pressurized state, but in the second embodiment, a state in which both are pressed and a state in which they are released can be selected. It has a configuration.

In the image forming apparatus having the above-described configuration, the release state is selected at the start of recording, and in this state, the running of the developing member 102 and the power supply to the heating member 131 are started.
Then, when the temperature of the heating body 131 reaches the set temperature, a temperature reaching signal is output and the pressurized state is selected. According to this method, the contact amount at the transfer / fixing portion is weak in the released state, and thus the charge amount of the developing object 102 is small. In the pressurized state, the contact force of the object to be developed 102 is increased and the member is charged. However, since the temperature of the heating member 131 is already sufficiently high, the charge is neutralized by the heat carrier generated inside the object to be developed 102, The charge amount of the developing object 102 can be reduced, and a stable image can always be formed.

FIG. 13 is a view showing a released state of the transfer / fixing section, and FIG. 14 is a view showing a pressurized state of the transfer / fixing section.
In the figure, reference numeral 102 denotes a developing object, 131 denotes a heating body, 13
3 is a pressure roller, 155 is a first frame that rotatably supports the heating element 131, and 156 is a pressure roller 13
3 is a second frame that rotatably supports 3. The first
The frame 155 is fixed to the main body of the image forming apparatus, and the second frame 156 is
55 is supported so as to be swingable about a support shaft 157.

Reference numeral 158 denotes a spring for urging the pressure roller 133 supported by the second frame 156 against the heating element 131 supported by the first frame 155. 159 is a solenoid for swinging the second frame 156 against the urging force of the spring 158, and the plunger 160 of the solenoid 159
It is connected to the frame 156. The above solenoid 15
When the plunger 160 is suctioned by turning on 9, the second frame 156 swings against the urging force of the spring 158, and the pressure roller 133 and the heating body 131 are released.

Therefore, in the pressurized state, the developing object 102 is pressurized by the urging force of the spring 158,
In the released state, the solenoid 159 operates against the urging force of the spring 158, and the pressure is released. The solenoid 159 is operated by a selection signal (not shown). In the case of the first embodiment, the developer 1
02 is stopped and pressurized.
1 is supplied and this state is maintained until a certain temperature is reached. Therefore, only a specific portion of the developing object 102 is heated and pressurized, and the characteristics of the portion may be deteriorated. In the case of the second embodiment, since the developing object 102 is not pressed until the temperature reaches a certain temperature, it is possible to prevent the characteristics from deteriorating.

It should be noted that the present invention is not limited to the above-described embodiment, but can be variously modified based on the gist of the present invention, and these are not excluded from the scope of the present invention.

[0052]

As described above in detail, according to the present invention, the developing member on which the toner image has been formed is sent to the transfer / fixing section composed of the heating member and the pressure roller, and the recording paper is formed. Is pressed and heated. The toner image is melted by heating, penetrates the recording paper by pressure, and transfer and fixing are performed simultaneously.

The heating element is heated to maintain a set temperature required for fixing. The object to be developed is on standby until the heating element reaches the set temperature, and the set temperature is reached. The running is started later. When the developing object is pressed by the heating element and the pressure roller in the transfer / fixing section, the developing element is charged. However, when the developing element moves to the transfer / fixing section, the heating element is set at the set temperature. , The heat carrier generated inside the developing member neutralizes the charge generated by the charging. As a result, the electric field intensity of the electric field generated through the developing object when the toner adheres to the developing object in the developing process does not change.

Therefore, it is possible to prevent the image from deteriorating due to the background fogging in the non-image portion and the increase or decrease of the recording density. Further, in the case where support means for selectively placing the heating element and the pressure roller in the released state and the pressure state is provided, the heating element and the pressure roller are released until the heating element reaches a set temperature. There is provided switching means for setting a state and a pressurized state after reaching a set temperature. In this case, the developing body is not pressed by the heating body and the pressure roller until the heating body reaches the set temperature, so that the developing body is not charged. When the object to be developed is pressurized, the heating element has reached the set temperature, so that even if the object to be developed is charged, the charge is neutralized by the heat carrier.

In this case, similarly, when the toner is adhered to the developing object in the developing process, the electric field intensity of the electric field generated through the developing object does not change, and the non-image portion is not fogged. It is possible to prevent an image from deteriorating due to generation of the recording density or an increase or decrease in the recording density.

[Brief description of the drawings]

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

FIG. 2 is a schematic configuration diagram of a conventional image forming apparatus.

FIG. 3 is a time chart illustrating a recording sequence of a conventional image forming apparatus.

FIG. 4 is a time chart illustrating a recording sequence of the image forming apparatus according to the first exemplary embodiment of the present invention.

FIG. 5 is a block diagram of a power supply control device in the image forming apparatus of the present invention.

FIG. 6 is a diagram illustrating a charging process in the image forming apparatus of the present invention.

FIG. 7 is a view showing an exposure process in the image forming apparatus of the present invention.

FIG. 8 is a diagram illustrating a developing process in the image forming apparatus of the present invention.

FIG. 9 is a diagram illustrating a light neutralization process in the image forming apparatus of the present invention.

FIG. 10 is a state diagram of a separation unit in the image forming apparatus of the present invention.

FIG. 11 is a diagram illustrating a transfer / fixing process in the image forming apparatus of the present invention.

FIG. 12 is a time chart illustrating a recording sequence of the image forming apparatus according to the second exemplary embodiment of the present invention.

FIG. 13 is a diagram illustrating a released state of a transfer / fixing unit.

FIG. 14 is a diagram illustrating a pressurized state of a transfer / fixing unit.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 101 Electrostatic latent image carrier 102 Developed object 104 Charging device 105 Exposure device 106 Developing device 114 Recording paper 131 Heating body 133 Pressure roller 151 Temperature detection sensor 152 Temperature setting circuit 153 Comparator 154 Power supply control circuit 155 First frame 156 Second frame 158 Spring 159 Solenoid 160 Plunger

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G03G 15/16 G03G 15/24

Claims (2)

(57) [Claims] 1. An electrostatic latent image carrier, (b) a charging device for charging a surface of the electrostatic latent image carrier, and (c) an electrostatic latent image carrier by exposing the electrostatic latent image carrier to light. An exposure device that forms an electrostatic latent image; (d) a developing object that is in close contact with and superimposed on the electrostatic latent image carrier on which the electrostatic latent image has been formed; A developing device which develops the above-mentioned developing object to form a toner image corresponding to the electrostatic latent image; and (f) a developing device comprising a heating body and a pressure roller, wherein the developing image and the recording paper are formed. A transfer / fixing unit for simultaneously performing transfer and fixing by applying pressure and heating in a state where the heating elements are stacked, (g) means for heating the heating element and maintaining the temperature at a set temperature, and (h) means for heating the heating element. An image forming apparatus comprising: means for starting the running of the developing object after the temperature reaches a set temperature. 2. An electrostatic latent image carrier, (b) a charging device for charging a surface of the electrostatic latent image carrier, and (c) an electrostatic latent image carrier by exposing the electrostatic latent image carrier to light. An exposure device that forms an electrostatic latent image; (d) a developing object that is in close contact with and superimposed on the electrostatic latent image carrier on which the electrostatic latent image has been formed; A developing device which develops the above-mentioned developing object to form a toner image corresponding to the electrostatic latent image; and (f) a developing device comprising a heating body and a pressure roller, wherein the developing image and the recording paper are formed. A transfer / fixing unit for simultaneously performing transfer and fixing by applying pressure and heating in a state in which the heating element and the pressure roller are overlapped; (g) supporting means for selectively placing the heating element and the pressure roller in a released state and a pressed state; (H) means for heating the heating element and maintaining the set temperature, and (i) means for heating the heating element and the pressure roller.
An image forming apparatus comprising: a switching unit that keeps the heating element in an open state until the heating element reaches a set temperature and pressurizes the heating element after the heating element reaches the set temperature.