JPH0728357A - Powder developer and image forming device - Google Patents

Abstract

PURPOSE:To provide a powder developer and an image forming device, capable of suppressing the rising of a temperature at the time of fixing and reducing the pressurizing force of a paper sheet required for fixing. CONSTITUTION:The powder developer is formed so as to include nonferrous conductive powder in a toner grain. Moreover, a photosensitive body 16 on which an electrostatic latent image is formed, a developing means 19 using the powder developer, to develop the electrostatic latent image, a transfer means 17 facing the photosensitive body 16, an electromagnetic fixing means 34 composed of a coil arranged in the rear step of the transfer means 17 and facing the paper carrying path 15 and a power source part applying a high frequency voltage to the coil and a pressurizing/fixing means 37 arranged on the rear step of the electromagnetic fixing means 34 and having a pair of pressure rollers 38 and 39 press-contacting each other so as to hold the paper carrying path 15 therebetween are provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a powder developer and an image forming apparatus.

[0002]

2. Description of the Related Art Conventionally, various fixing methods have been developed in an image forming apparatus in which a developed image developed on a photoconductor is transferred onto a sheet and the transferred image is fixed.
That is, a heat fixing method, a pressure fixing method, and JP-A-60-
There are a flash fixing method described in 128476 and the like, a high frequency heat fixing method described in JP-A-58-63969 and the like.

[0003]

In the heat fixing method and the flash fixing method, it takes a long time until the fixing temperature is reached after the power is turned on, it cannot be used immediately, and the power consumption is high. Furthermore, measures against temperature rise are also required. Since the pressure fixing method does not apply heat, fixing cannot be performed unless the pressure of the pressure roller is increased. Therefore, it is necessary to strengthen the support structure of the pressure roller. The image quality is deteriorated because the image is destroyed.

In the conventional high-frequency heat fixing method, a high-frequency voltage is applied to the coil and the developer is fixed by the heat generated at that time. However, the developer containing magnetic powder in the toner particles is used. Since it is used, the magnetic powder easily gathers together with the toner particles in the magnetic force lines generated when the coil is energized.
As a result, the fixed image may be displaced depending on the position where the magnetic force lines pass.

[0005]

The invention according to claim 1 is
Non-ferrous conductive powder was included inside the toner particles to form a developer.

According to a second aspect of the present invention, the electrostatic latent image is developed using a photoconductor on which an electrostatic latent image is formed and a powder developer in which toner particles contain non-ferrous conductive powder. Electromagnetic fixing means including a developing means, a transfer means facing the photoconductor, a coil arranged at a subsequent stage of the transfer means and facing a sheet conveying path, and a power supply section for applying a high frequency voltage to the coil. The pressure-fixing means is arranged in the latter stage of the electromagnetic fixing means and has a pair of pressure rollers which are in pressure contact with each other with the sheet conveying path in between.

According to a third aspect of the present invention, in the second aspect of the invention, a branch discharge path branched from the sheet conveyance path is provided between the electromagnetic fixing means and the pressure fixing means, and the branch discharge path is provided. And a sheet conveying path, a conveying direction changing means for changing the conveying direction of the sheet is provided, and the sheet inserting path joined to the sheet conveying path is formed between the conveying direction changing means and the pressure fixing means. Provided.

[0008]

According to the first aspect of the present invention, when the image transferred to the paper is fixed by the electromagnetic fixing means, the non-ferrous conductive powder contained in the toner particles can rapidly dissolve the toner particles by the heat generating effect. In addition, since the position of the non-ferrous conductive powder does not change due to the magnetic lines of force generated from the electromagnetic fixing unit, distortion of the fixed image on the paper can be prevented.

According to the second aspect of the invention, since the particles of the powder developer developed on the photoreceptor and transferred to the paper are toner particles containing non-ferrous conductive powder, the image transferred to the paper is When the toner is fixed by the electromagnetic fixing means, the toner particles can be quickly dissolved by the heat generating action of the non-ferrous conductive powder contained in the toner particles, and the non-ferrous conductive powder is generated by the magnetic force lines generated from the electromagnetic fixing means. Since the position of does not fluctuate, it is possible to prevent distortion of the fixed image on the paper, and finally fix it by the pressure fixing means after fixing it by the electromagnetic fixing means. The pressure roller of the means can reduce the pressing force.

According to the third aspect of the present invention, by operating the conveying direction changing means, the sheet supposedly attached by the electromagnetic fixing means can be discharged from the branch discharge path without passing through the pressure fixing means. As a result, the image on the paper can be erased as necessary after checking the print content before the main fixing. Further, the image on the paper can be permanently fixed by the pressure fixing means by inserting the image from the paper insertion path regardless of whether the image is erased.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the drawings. In FIG. 1, 1 is a housing. The housing 1 is formed by joining a bottom cover 2 and a top cover 3. An opening / closing cover 4 is rotatably held around a fulcrum shaft 5 at a lower edge in front of the bottom cover 2, and a paper discharge tray 6 is rotatably around a fulcrum shaft 7 in a central portion of the top cover 3. Is held. Further, on the back surface of the bottom cover 2, there are provided a paper feed tray 9 for accommodating the sheets 8 in a stacked state and a manual feed tray 10 for feeding the sheets 8 one by one. Further, a pressing plate 13 for pressing the paper 8 supplied from the paper feed tray 9 and the manual feed tray 10 toward the paper feed roller 12 side by the urging force of the spring 11 is provided around the fulcrum shaft 14 below the bottom cover 2. It is rotatably held by.

Next, the photoconductor 16 and the transfer means 17 located below the photoconductor 16 are opposed to each other with the paper conveyance path 15 provided along the bottom surface of the bottom cover 2 in between.
Around the photosensitive member 16, a charging means 18 using a brush,
Developing means 19 and cleaning means 20 are arranged,
Behind the developing means 19, an exposing means 21 is provided.

The developing means 19 includes a developer container 23 to which powder developer is replenished by a developer cartridge 22.
The developing roller 24, a blade 25 facing the developing roller 24, a replenishing roller 26 that charges the powder developer by friction between the developing roller 24, and an agitator 27 that stirs the powder developer are provided. is there. As shown in FIG. 3, the developing means 19 develops using a powder developer 30 in which toner powder 28 contains aluminum powder 29 which is a non-ferrous conductive powder.

The exposing means 21 scans the beam emitted from the laser diode 31 with a polygon mirror 32, and scans the scanning light through the mirror 33.
6 is irradiated.

An electromagnetic fixing means 34 is provided in the paper conveyance path 15 at a stage subsequent to the transfer means 17. The electromagnetic fixing unit 34 has a coil 35 and a power supply unit 36 that applies a high frequency voltage to the coil 35 (see FIG. 3). A pressure fixing unit 37 is provided after the electromagnetic fixing unit 34. This pressure fixing means 37
Has a pair of pressure rollers 38 and 39 which are pressed against each other with the sheet conveyance path 15 in between.

Further, the terminal end of the paper transport path 15 is connected to the entrance of the paper discharge receiver 6 by a paper discharge path 40, and a paper discharge roller 41 is provided at the terminal end of the paper discharge path 40. Further, a branch discharge path 42 branched from the paper transport path 15 is provided between the electromagnetic fixing means 34 and the pressure fixing means 37, and the branch discharge path 42 and the paper transport path 15 are branched. At the point, a lever 43 as a conveying direction changing means for changing the conveying direction of the paper 8 is connected to a driving source such as an electromagnet (not shown) and is provided so as to be rotatable around a fulcrum shaft 44. Further, a paper insertion path 45 joined to the paper conveyance path 15 is provided between the lever 43 and the pressure fixing means 37. The ends of the sheet insertion path 45 and the branch discharge path 42 face the inner surface of the opening / closing cover 4.

As shown in FIG. 2, a power switch 46 and an LED 47 for indicating the on / off state of the power switch 46 are provided on one side of the housing 1, and various types are provided on the upper surface of the other side. Display units 48 for displaying the operating state of the
Is provided.

In such a structure, the photoconductor 16 is charged by the charging means 18 in the process of being driven, and the charged portion is irradiated with the beam modulated based on the print signal from the exposure means 21 to cause the electrostatic latent image. An image is formed. This electrostatic latent image is developed by the developing means 19. On the other hand, the paper 8 is supplied by the paper feed roller 12 in synchronization with the rotational movement of the photoconductor 16, and the developed image on the photoconductor 16 is transferred to the paper 8 by the transfer unit 17. Then, in the process in which the sheet 8 is conveyed toward the discharge tray 6, the image on the sheet 8 is tentatively attached by the electromagnetic fixing unit 34, and the pressure fixing unit 3 is attached.
It is permanently fixed by 7.

Here, referring to FIG. 3, the electromagnetic fixing means 34
The fixing action by will be described. The particles of the powder developer 30 before reaching the electromagnetic fixing unit 34 have poor adhesion to the sheet 8 because the toner particles 28 have not yet been melted.
On the other hand, when a high-frequency voltage is applied to the coil 35, high-frequency magnetic force lines a are generated in a loop shape, and when the powder developer 30 reaches the loop of the magnetic force lines a, the aluminum powder 29 is induction-heated. By this induction heating, the toner particles 28 are melted and brought into close contact with the paper 8, but are crushed by the pressure rollers 38 and 39 to further improve the close contact with the paper 8.

As described above, since the particles of the powder developer 30 are the toner particles 28 including the aluminum powder 29, the image transferred onto the sheet 8 is electromagnetically fixed by the toner 34.
When fixing, the toner particles 28 can be rapidly dissolved by the heat generation effect of the aluminum powder 29. Further, since the position of the aluminum powder 29 does not change due to the magnetic lines of force a generated from the electromagnetic fixing means 34, it is possible to prevent distortion of the fixed image on the paper 8.

Further, the pressure fixing of the pressure rollers 38 and 39 of the pressure fixing means 37 can be reduced by finally fixing by the pressure fixing means 37 after the assumption fixing by the electromagnetic fixing means 34. As a result, the pressure rollers 38, 39
The support structure can be simplified. Moreover, since it is possible to prevent the transfer image from being crushed by the pressure rollers 38 and 39, the image quality can be improved in this respect as well.

Further, as shown by phantom lines in FIG. 1, the opening / closing cover 4 is opened, and the lever 43 is rotated to connect the sheet conveying path 15 to the branch sheet discharging path 42. The hypothetically attached sheet 8 can be discharged from the branched sheet discharge path 42 without passing through the pressure fixing means 37. As a result, after the print content is checked before the main fixing, the image on the sheet 8 can be erased as necessary by an eraser or the like. Further, the image on the sheet 8 can be permanently fixed by the pressure fixing unit 37 by inserting the image from the sheet insertion path 45 regardless of whether the image is erased.

The photoconductor 16 is generally formed by coating the outer circumference of an aluminum tube with an organic photoconductor layer. However, by using a polishing agent containing aluminum to polish the surface, It was found that the life of the upper photoconductor 16 is extended. In view of this point, the toner particles 28
Aluminum powder as non-ferrous conductive powder included in 2
By using 9, the compatibility with the photoconductor 16 is improved,
It is possible to contribute to the extension of the life of the photoconductor 16.

[0024]

According to the first aspect of the present invention, since the non-ferrous conductive powder is included in the toner particles to form the powder developer, the toner is fixed when the image transferred to the paper is fixed by the electromagnetic fixing means. Due to the heat generation effect of the non-ferrous conductive powder contained in the particles, the toner particles can be quickly dissolved, which can suppress the temperature rise in the apparatus, and the magnetic flux generated from the electromagnetic fixing unit. Since the position of the non-ferrous conductive powder does not change, distortion of the fixed image on the paper can be prevented.

According to the second aspect of the invention, as described above, the developing means is provided for developing the electrostatic latent image on the photoconductor by using the powder developer in which the non-ferrous conductive powder is contained in the toner particles. Since an electromagnetic fixing unit including a coil and a power supply unit for applying a high frequency voltage to the coil is provided, and a pressure fixing unit having a pair of pressure rollers pressed against each other is provided, an image transferred onto a sheet is electromagnetically transferred. When fixing by the fixing means, the heat generation effect of the non-ferrous conductive powder contained in the toner particles can rapidly dissolve the toner particles, and the magnetic force lines generated from the electromagnetic fixing means can position the non-ferrous conductive powder. Does not fluctuate, so it is possible to prevent distortion of the fixed image on the paper, and finally fix it by the pressure fixing means after the assumption fixing by the electromagnetic fixing means. It can be a pressure roller to reduce the pressure.

According to a third aspect of the invention, as described above, in the third aspect of the invention, a branch paper discharge path branched from the paper transport path is provided between the electromagnetic fixing means and the pressure fixing means, A conveyance direction changing means for changing the conveyance direction of the paper is provided at a branch point between the branch discharge path and the paper conveyance path, and the paper conveyance path is joined between the conveyance direction change means and the pressure fixing means. Since the paper insertion path is provided, by operating the conveyance direction changing means, the paper that is supposedly attached by the electromagnetic fixing means can be discharged from the branch paper discharge path without passing through the pressure fixing means. The image on the paper can be erased if necessary after checking the print content before the main fixing. Further, the image on the sheet can be permanently fixed by the pressure fixing unit by inserting the image from the sheet insertion path regardless of whether the image is erased.

[Brief description of drawings]

FIG. 1 is a vertical sectional side view showing an embodiment of the present invention.

FIG. 2 is a perspective view.

FIG. 3 is an explanatory diagram showing a fixing action.

[Explanation of symbols]

 15 paper conveying path 16 photoconductor 17 transfer means 19 developing means 28 toner particles 29 non-ferrous conductive powder 30 powder developer 34 electromagnetic fixing means 35 coil 36 power supply section 37 pressure fixing means 38, 39 pressure roller 42 branch discharge path 43 transport direction changing means 45 paper insertion path

Claims (3)

[Claims] 1. A powder developer comprising non-ferrous conductive powder contained in toner particles. 2. A photosensitive member on which an electrostatic latent image is formed, developing means for developing the electrostatic latent image using a powder developer in which toner particles contain non-ferrous conductive powder, and the photosensitive member. An electromagnetic fixing unit including a transfer unit that faces the body, a coil that is arranged at a subsequent stage of the transfer unit and that faces the sheet conveying path, and a power supply unit that applies a high-frequency voltage to the coil. An image forming apparatus comprising: a pressure fixing unit having a pair of pressure rollers which are arranged and are in pressure contact with each other with the sheet conveyance path in between. 3. A branch paper discharge path branched from the paper transport path is provided between the electromagnetic fixing means and the pressure fixing means, and a paper transport direction is set at a branch point between the branch paper discharge path and the paper transport path. 3. The image forming apparatus according to claim 2, further comprising: a transfer direction changing unit that changes the transfer direction, and a sheet insertion path that joins the sheet transfer path between the transfer direction changing unit and the pressure fixing unit. apparatus.