JPH0580598A - Electrophotographic device - Google Patents

Abstract

PURPOSE:To avoid the soiling of a transfer form caused by the scattering of toner and further, to put the transfer forms in original order, without having wrinkles, jamming. etc., on the transfer farm. CONSTITUTION:A recording material carrying path composed of carrier guiding plates 15 and an ejected paper guiding plates 22, are roughly linearly disposed in a horizontal direction in the upper location of a developing device 2, and simultaneously, a toner image is transferred/fixed on the back surface of the transfer form P carried in the recording carrying path.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic apparatus for forming an image by forming a toner image on the surface of a photoconductor and then transferring and fixing the toner image on a recording material.

[0002]

2. Description of the Related Art Conventionally, an electrophotographic apparatus generally prints by developing a toner image corresponding to an image pattern on a photosensitive drum surface by a developing device and transferring the toner image onto a transfer paper. ing. Further, the electrophotographic apparatus as described above is provided with an exposing means for exposing the surface of the photosensitive drum for developing the toner image. As the exposing means, as shown in FIG. 7, an optical system member 30 is provided. As shown in FIG. 8, the laser type laser which directly irradiates the surface of the photoconductor drum 31 with the reflected light from the original is supplied with the light corresponding to the image pattern signal from the exposure control device (not shown).
L that irradiates the surface of the photosensitive drum 41 from the ED array 40
Some are ED type.

By the way, the above laser type and L
In the ED type electrophotographic apparatus, the optical system member 30 and the LE
Since the D array 40 is arranged outside the photoconductor drum 31 (41), there is a problem that the entire apparatus inevitably becomes large.

Therefore, in recent years, as shown in FIG. 9 or 10, a photosensitive drum 51 (61) having a photosensitive layer formed on a cylindrical transparent substrate is provided, and the photosensitive drum 51 (61) is provided. ) LED array 50 (60)
There has been proposed an electrophotographic apparatus provided with. In such an electrophotographic apparatus, exposure can be performed from the inside of the photosensitive drum 51 (61), so that the apparatus is significantly downsized.

[0005]

However, in the conventional electrophotographic apparatus shown in FIG. 9 as in the above-described conventional electrophotographic apparatus, as in the electrophotographic apparatus shown in FIG. 7 and FIG. Since it is arranged below the photosensitive drum 51, when the toner image is developed on the surface of the photosensitive drum 51,
In the case where the toner is scattered from the developing device 52 disposed on the side, the transfer paper P is soiled due to the toner scattering. Furthermore, when printing on a plurality of transfer papers P, the toner images are transferred and fixed on the upper surface of the transfer papers P, so that the transfer papers P cannot be arranged in the order of the originals. It should be noted that there is a printer provided with a mechanism for reversing the transfer paper P in the middle of the conveying path so as to align the transfer paper P according to the order of the originals in the printing of a plurality of sheets as described above.
This structure has a problem that the transfer paper P is wrinkled, jammed, or the like.

On the other hand, in the electrophotographic apparatus shown in FIG. 10, since the transport path for the transfer paper P is arranged from above the developing device 62 in the downward inclination direction, the transfer paper due to the toner scattering from the developing device 62. Although the stain of P does not occur,
Since the accommodation case 63 for accommodating the transfer paper P has to be provided so as to project from the upper end exterior portion of the apparatus main body, there is a problem in that the apparatus becomes larger by that amount.

[0007]

In order to solve the above-mentioned problems, the electrophotographic apparatus according to claim 1 of the present invention develops a toner image on the surface of the photoconductor by a developing device and records the toner image. In an electrophotographic apparatus that forms an image by transferring to a recording material conveyed through a material conveying path,
The following measures are taken.

That is, the recording material conveying path is arranged above the developing device.

In order to solve the above problems, the electrophotographic apparatus according to the second aspect of the invention has the following means in the electrophotographic apparatus according to the first aspect.

That is, the recording material conveying path is disposed in the apparatus in a substantially straight line in the horizontal direction, and the recording material conveyed in the recording material conveying path has a toner image on its lower surface. Transferred and fixed.

In order to solve the above-mentioned problems, the electrophotographic apparatus according to the third aspect of the invention has the following means in the electrophotographic apparatus according to the first aspect.

That is, the upper exterior part of the developing device is arranged in the recording material conveying path and supports the recording material to be conveyed.

In order to solve the above problems, the electrophotographic apparatus according to the fourth aspect of the invention has the following means in the electrophotographic apparatus according to the third aspect.

That is, the upper exterior part of the developing device is formed as a transport guide plate for guiding the recording material in the transport direction.

[0015]

According to the structure described in claim 1, since the recording material conveying path of the recording material for transferring and fixing the toner image is disposed above the developing device, the toner image is formed on the surface of the photosensitive member. Even when the toner is scattered from the developing device at the time of development, there is no possibility that the recording material is contaminated due to the toner scattering.

According to the second aspect of the invention, the recording material conveyed in the recording material conveying path is conveyed in a substantially straight line in the horizontal direction in the apparatus, and the toner image is transferred on the lower surface side thereof.・
It has become established. Therefore, when printing is performed on a plurality of sheets, the recording materials can be arranged in the order of the originals without causing wrinkles or jams on the recording materials.

Further, according to the third aspect of the invention, since the upper exterior portion of the developing device is arranged in the recording material conveying path so as to support the recording material, the developing device serves as the recording material conveying path. This can be utilized, and eventually, the number of parts of the constituent members forming the recording material conveying path can be reduced.

According to the fourth aspect of the invention, the recording material is guided in the conveying direction by forming the upper exterior part of the developing device forming a part of the recording material conveying path as the conveying guide plate. It is possible to improve the transportability of the recording material.

[0019]

【Example】

[Embodiment 1] FIG. 1 through FIG.
The explanation is based on the following.

As shown in FIG. 1, the electrophotographic apparatus according to the present embodiment is equipped with a photosensitive drum 1 which is a cylindrical photosensitive member rotatable in the direction A in the apparatus. A developing device 2 is provided on the right side of the photoconductor drum 1, an exposure device 7 is provided inside the photoconductor drum 1, and a dielectric belt 8 is provided above the photoconductor drum 1.

As shown in FIG. 3, the photosensitive drum 1 has a surface of an optically transparent cylindrical transparent support 1a,
A transparent conductive layer 1b made of a sputtered film such as In ₂ O ₃ or SnO ₂ ,
A photoconductive layer 1c made of a photoconductive material such as Se, ZnO, CdS, or amorphous Si is sequentially laminated.
In this embodiment, the transparent conductive layer 1b has a film thickness of
An In ₂ O ₃ layer having a thickness of 0.5 μm is formed, and an amorphous Si layer having a thickness of 3 μm is formed as the photoconductive layer 1c.

The developing device 2 includes a developing tank 3 for storing a conductive toner T as a developer, and a stirring roller 4 rotatably provided in the developing tank 3 for stirring the conductive toner T.
A toner holder 5 disposed at a position facing the photoconductor drum 1 in the opening 3a of the developing tank 3, and a doctor blade 6 fixedly provided at a position below the toner holder 5 in the opening 3a of the developing tank 3. It consists of and.

The toner holder 5 extends along the longitudinal direction of the photosensitive drum 1 and has N polarity and S in the circumferential direction.
A magnetic roller 5a in which magnets with polarities are alternately arranged, and a developing sleeve 5b made of non-magnetic material such as aluminum or martensitic stainless steel and provided so as to cover the outer peripheral surface of the magnetic roller 5a. Consists of. Then, the toner holder 5 holds the conductive toner T on the surface of the developing sleeve 5b by the alternating magnetic field generated by the rotation of the magnetic roller 5a in the direction B in the apparatus, and rotates in the rotating direction of the magnetic roller 5a. The sheet is conveyed in the B'direction, which is the opposite direction to the certain B direction. Further, the doctor blade 6 adjusts the carrying amount of the conductive toner T held on the surface of the developing sleeve 5b and carried in the B ′ direction as described above to a predetermined amount.

The conductive toner T is obtained by kneading a resin made of styrene-acrylic copolymer with magnetic powder such as iron powder or ferrite, carbon black, etc.
It is composed of powder having a size of several μm to several tens of μm.

The exposure device 7 is composed of an LED array in which a light-emitting diode and a short focus lens are combined, and the direction of the developing device 2 is changed according to an image pattern signal from an exposure control device (not shown). The irradiation light is directed to the photoconductive layer 1c through the transparent support 1a of the photosensitive drum 1 and the transparent conductive layer 1b.

The dielectric belt 8 is formed into an endless belt shape using a film material mainly composed of a polyimide resin having excellent mechanical strength and high heat resistance.
The dielectric belt 8 includes a transfer roller 9 disposed above the photosensitive drum 1, a heating device 10 described later disposed slightly above the transfer roller 9 on the left side in the drawing, and Three with the tension roller 11 arranged on the lower left side of the heating device 10
1 is wound around these so as to surround 1 from the outside, and between the photosensitive drum 1 and the transfer roller 9,
It is in a state of being sandwiched by the photosensitive drum 1 and the transfer roller 9.

A film-shaped polyimide resin is used as the material of the dielectric belt 8, but the material is not particularly limited to this material, and the conductive toner T is transferred at least as described later. Any surface may be used as long as it has an insulating property. For example, a metal belt such as an electroformed nickel belt as a base material may be coated with fluorine. Also, the dielectric belt 8
Is not particularly limited in its thickness, but in consideration of thermal conductivity and mechanical strength, a thickness of about 10 μm to 200 μm is preferable, and even if the surface is roughened in order to make the gloss of the image moderate. Good.

The heating device 10 is for heating and melting the conductive toner T transferred onto the surface of the dielectric belt 8, as will be described later, and includes a planar Mo-based heating resistor 10a on an alumina ceramic substrate. It is composed of a ceramic heater which is printed and on which a glass coat is printed and laminated. The heating device 10 is configured to quickly raise the temperature to a predetermined heating temperature by energizing the heating resistor 10a, and the heating surface is arranged so as to be in direct contact with the surface of the dielectric belt 8. Has been done.

A pressure roller 12 which is rotated while applying a pressing force in a direction toward the heating device 10 via the dielectric belt 8 is arranged at the upper portion of the heating device 10. The roller 12 sandwiches a transfer sheet P, which is a recording material, conveyed by a sheet feeding unit 14 described later, at a pressure contact portion with the dielectric belt 8.

In addition, the electrophotographic apparatus of this embodiment has the structure shown in FIG.
As shown in FIG. 3, a stepping motor 13 that is a drive source of the apparatus, the above-mentioned sheet feeding unit 14 that feeds the transfer sheet P to the pressure contact portion between the dielectric belt 8 and the pressure roller 12, and the transfer sheet from inside the apparatus. A paper output means 21 for discharging P is provided.

The paper feeding means 14 is disposed above the photoconductor drum 1, the developing device 2 and the dielectric belt 8, and its constituent members are dielectric from a transfer paper supply opening (not shown). Transport guide plates 15, 15 forming a paper feed path connecting the body belt 8 and the pressure roller 12 to the pressure contact portion,
Paper entry detection actuator 16, paper entry detection switch 17, and paper feed roller 1 arranged near the transfer paper supply opening.
8 and 18, registration rollers 19 and 19 arranged on the way of the conveyance guide plates 15 and 15, and a registration solenoid 20 that controls the rotation of the registration rollers 19.

The paper output means 21 is disposed on the left side of the pressure contact portion between the dielectric belt 8 and the pressure roller 12, and its constituent member is the pressure contact between the dielectric belt 8 and the pressure roller 12. Paper output guide plates 22 and 22 forming a paper output path connecting a transfer sheet to a transfer paper discharge opening (not shown), and the dielectric belt 8.
Of the paper output detection actuator 23 and the paper output detection switch 24, which are arranged in the vicinity of the pressure contact portion between the pressure roller 12 and the pressure roller 12, and the paper discharge rollers 25.2 arranged at the end side of the paper output guide plate 22.
5 and.

The sheet feeding means 14 and the sheet discharging means 21 constitute a recording material conveying means for conveying the transfer sheet P as a recording material in the apparatus, and a conveying guide forming a sheet feeding path. Plates 15 and 15 and a paper output guide plate 2 forming a paper output path
The recording material conveying path according to the present invention is constituted by 2.22.

Regarding the operation of the electrophotographic apparatus having the above structure,
It will be described next.

First, the transfer paper feeding means (not shown)
When a sheet of transfer paper P is fed from the transfer paper supply opening,
When the leading edge of the transfer paper P pushes up the paper input detection actuator 16, the paper input detection switch 17 detects the supply of the transfer paper P and outputs a paper input detection signal to the stepping motor 13.
And the stepping motor 13 as a drive source is rotationally driven.

Next, the rotation of the stepping motor 13 is transmitted to the paper feed roller 18 via a rotation transmission mechanism (not shown), whereby the paper feed roller 18 is rotated, and with the rotation of the paper feed roller 18, The transfer paper P is the registration roller 1
9 is transported.

The transfer sheet P conveyed to the registration roller 19 as described above is once in a state where the conveyance is stopped when the rotation of the registration roller 19 is stopped by the control of the registration solenoid 20. At this time, the sheet feeding rollers 18, 18 are in a state of sandwiching the rear end side of the transfer sheet P, and the resistance of the roller surface is small, so that the transfer sheet P is stopped when the transfer sheet P is stopped. It is a slipped state on both sides.

Next, the developing process of the conductive toner T will be described with reference to FIGS.

First, as shown in FIG. 3, the conductive toner T stored in the developing tank 3 is transferred to the developing sleeve 5 by the alternating magnetic field generated by the rotation of the magnetic roller 5a in the B direction.
While being held on the surface b, it is conveyed on the surface of the developing sleeve 5b in the direction B'which is opposite to the direction A which is the rotation direction of the photosensitive drum 1. At this time, the conductive toner T held on the surface of the developing sleeve 5b and the photosensitive drum 1
At the contact portion with the developing sleeve 5b, the developing sleeve 5b and the transparent conductive layer 1b are applied with a potential difference of several tens of V applied between them.
Charge is injected from the b to the photoconductor drum 1 through the conductive toner T, and the surface of the photoconductor drum 1 is charged to substantially the same potential as the developing sleeve 5b.

The conductive toner T which is brought into contact with the photosensitive drum 1 as described above is subjected to the magnetic force generated by the magnetic roller 5a when the surface of the photosensitive drum 1 and the developing sleeve 5b become equipotential. Since it acts predominantly, it does not adhere to the photosensitive drum 1.

Next, as shown in FIG. 4, the photosensitive drum 1
When the LEDs corresponding to the image pattern of the original are sequentially selected and exposed by the exposure device 7 immediately before the conductive toner T and the conductive toner T are separated from each other, or at a portion C near the conductive toner T, the light is injected onto the surface of the photosensitive drum 1. The electric charges that have been generated are neutralized, and a potential difference is generated between the surface of the photosensitive drum 1 and the developing sleeve 5b.

Thereafter, due to the potential difference as described above, charge is again injected from the developing sleeve 5b to the photosensitive drum 1 through the conductive toner T. However, before the charge injection is sufficiently performed, the charge is electrically connected to the photosensitive drum 1. Since the conductive toner T is separated from the conductive toner T, as shown in FIG. The magnetic force is shaken off to adhere to the surface of the photosensitive drum 1, and a toner image corresponding to the image pattern of the original is developed on the surface of the photosensitive drum 1.

The toner image developed on the surface of the photosensitive drum 1 as described above is passed through the dielectric belt 8 by applying a voltage having a polarity opposite to the injected charge of the toner image to the transfer roller 9. It is transferred onto the surface of the dielectric belt 8 at the pressure contact portion between the photosensitive drum 1 and the transfer roller 9. On the other hand, CPU (Ce
When the registration solenoid 20 outputs a signal to the registration solenoid 20, the rotation stop state of the registration roller 19 described above is released, and the transfer paper P is conveyed to the pressure contact portion between the dielectric belt 8 and the pressure roller 12. ..

Then, the dielectric belt 8 and the transfer paper P on which the above toner image has been transferred are heated by the heating device 10 and the pressure roller 1.
By being superposed and conveyed between the two sheets, the transfer and fixing of the toner image on the transfer sheet P are simultaneously performed. That is, when the transfer paper P is sent out while being pressed against the dielectric belt 8 and the pressure roller 12, the surface of the dielectric belt 8 is against the conductive toner T heated and melted by the heating device 10. However, since the releasing property is better than that of the transfer paper P, most of the conductive toner T on the surface of the dielectric belt 8 is transferred and fixed onto the transfer paper P.

After that, the transfer paper P on which the above-mentioned toner image is transferred and fixed is pushed up by the paper output detection actuator 23 and is discharged by the rotation of the paper discharge roller 25 onto the paper output tray (not shown) through the transfer paper discharge opening. It Then, after a predetermined time when the paper input detection signal from the paper input detection switch 17 and the paper output detection signal from the paper output detection switch 24 are no longer detected, the heating resistor 10a of the heating device 10 is energized, The driving of the stepping motor 13 is stopped, and the series of operations described above is completed.

The transfer paper P discharged onto the paper output tray as described above is in a state in which the surface on which the toner image has been transferred and fixed faces the paper output tray.

As described above, in the electrophotographic apparatus of this embodiment, the surface of the photoconductor drum 1 is charged by the conductive toner T held by the toner holding member 5 coming into contact with the photoconductor drum 1, and the photoconductor drum 1 is charged. The toner image corresponding to the image pattern is developed on the surface of the photoconductor drum 1 by performing exposure from the inside of the drum 1 by the exposure device 7, and the toner image developed on the surface of the photoconductor drum 1 is By the heating of the heating device 10 and the pressurization of the pressure roller 12, it is simultaneously transferred and fixed onto the transfer paper P via the dielectric belt 8.

By the way, the transfer sheet P on which the toner image is transferred and fixed as described above is conveyed through the recording material conveying path constituted by the conveying guide plates 15 and 15 and the paper ejection guide plates 22 and 22. The recording material conveyance path is arranged above the developing device 2 in a substantially straight line in the horizontal direction. Therefore, even when the conductive toner T is scattered from the developing device 2 when the toner image is developed on the surface of the photoconductor drum 1, there is no possibility that the transfer paper P is soiled due to the toner scattering. In the case of printing a plurality of sheets, since the toner image is transferred and fixed on the lower surface of the transfer paper P, the transfer paper P can be arranged in the order of the originals without causing wrinkles, jams, or the like on the transfer paper P. ..

[Second Embodiment] The following will describe another embodiment of the present invention with reference to FIG. The second embodiment has the same structure as that of the first embodiment except for the developing tank 3 and the transport guide plate 15 which constitute the developing device 2 of the first embodiment. The description of the configuration other than the device 2 and the transport guide plate 15 is omitted, and the members having the same functions as those in the first embodiment are designated by the same reference numerals.

As shown in FIG. 6, the developing device 2'of the present embodiment is disposed on the right side of the photosensitive drum 1, and its constituent members are the developing device 2 of the first embodiment. A stirring roller 4, a toner holder 5, and a doctor blade 6 similar to the above are provided, and an upper exterior portion is provided with a developing tank 3'formed as a transport guide plate 3'b.

The transport guide plate 3'b of the developing tank 3'is
The transfer paper P, which is arranged in the recording material conveyance path on the right side of the conveyance guide plate 15 ′ whose upstream side is shortened as compared with the conveyance guide plate 15 of the first embodiment, is conveyed by the rotation of the paper feed roller 18. The transfer paper P is guided in the carrying direction.

As described above, in the electrophotographic apparatus of this embodiment, the transport guide plate 3'b formed on the upper exterior portion of the developing tank 3'is formed as a part of the recording material transport path. Therefore, the transport guide plate 15 'can be made shorter than the transport guide plate 15 of the first embodiment, and as a result, the cost of the apparatus can be reduced.

The present invention is not limited to the first and second embodiments described above, but various modifications can be made within the scope of the present invention. For example, in the first and second embodiments, the toner image transferred and fixed on the transfer paper P is formed by the conductive toner T. However, the toner image is not particularly limited to this, and is used in the electrophotographic method. Conductive toner T
It is also possible to adopt a configuration in which development is performed using a toner other than the above.

[0054]

As described above, in the electrophotographic apparatus according to the first aspect of the present invention, the recording material conveying path is arranged above the developing device.

As a result, when the toner image is developed on the surface of the photosensitive member, even if the toner is scattered from the developing device, there is no possibility that the recording material is contaminated due to the toner scattering, and thus the image quality is improved. It is possible to provide an improved electrophotographic apparatus.

The electrophotographic apparatus according to claim 2 is the electrophotographic apparatus according to claim 1, wherein the recording material conveying path is
It is arranged in a straight line in the horizontal direction in the device.
The toner image is transferred and fixed on the lower surface of the recording material conveyed in the recording material conveying path.

As a result, when printing a plurality of sheets, it is possible to arrange the recording materials in order of originals without causing wrinkles or jams on the recording materials.

According to a third aspect of the present invention, in the electrophotographic apparatus according to the first aspect, the upper exterior portion of the developing device is arranged in the recording material conveying path and supports the recording material conveyed. It is a composition.

As a result, the developing device can be utilized as a recording material conveying path, and as a result, the cost of the apparatus can be reduced as the number of components of the recording material conveying path is reduced. Play.

According to a fourth aspect of the present invention, in the electrophotographic apparatus according to the third aspect, the upper exterior portion of the developing device is formed as a conveyance guide plate for guiding the recording material in the conveyance direction. Is.

Thus, by guiding the recording material supported on the developing device in the conveying direction, it is possible to improve the conveying property of the recording material.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing a photosensitive drum, a developing device, an exposing unit, and a dielectric belt that constitute an electrophotographic apparatus according to an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram showing various components constituting the electrophotographic apparatus.

FIG. 3 is an explanatory diagram showing a state where the surface of the photosensitive drum is charged by contact with conductive toner.

FIG. 4 is an explanatory diagram showing a state where the surface of the photosensitive drum is neutralized by exposure of an exposure device.

FIG. 5 is an explanatory diagram showing a state in which a toner image is developed on the surface of the photosensitive drum.

FIG. 6 is a vertical cross-sectional view showing a photosensitive drum, a developing device, an exposing unit, and a dielectric belt which constitute an electrophotographic apparatus according to another embodiment of the present invention.

FIG. 7 is a vertical cross-sectional view showing an electrophotographic apparatus including a conventional laser type exposure unit.

FIG. 8 is a longitudinal sectional view showing an electrophotographic apparatus in which a conventional LED array is arranged outside a photosensitive drum.

FIG. 9 is a vertical cross-sectional view showing an electrophotographic apparatus in which a conventional LED array is arranged inside a photosensitive drum.

FIG. 10 is a vertical cross-sectional view showing another electrophotographic apparatus in which the LED array of the conventional example is arranged in the photosensitive drum.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Photoconductor drum (photoconductor) 2 Developing device 3'Developing tank 3'b Transport guide plate 15 Transport guide plate (recording material transport path) 22 Paper ejection guide plate (recording material transport path) P Transfer paper (recording material)

Claims (4)

[Claims] 1. An electrophotographic apparatus for forming an image by developing a toner image on a surface of a photoconductor by a developing device and transferring the toner image onto a recording material conveyed through a recording material conveying path. The electrophotographic apparatus, wherein the recording material conveyance path is disposed above the developing device. 2. The recording material conveying path is arranged substantially linearly in a horizontal direction in the apparatus, and the recording material conveyed in the recording material conveying path has a toner image on its lower surface. The electrophotographic apparatus according to claim 1, wherein the electrophotographic apparatus is transferred and fixed. 3. The electrophotographic apparatus according to claim 1, wherein the upper exterior portion of the developing device is arranged in a recording material conveying path to support the recording material to be conveyed. 4. The electrophotographic apparatus according to claim 3, wherein the upper exterior portion of the developing device is formed as a transport guide plate for guiding the recording material in the transport direction.