JPH0580597A - Electrophotographic device - Google Patents

Abstract

PURPOSE:To improve the maintainability of a device by making the opening/ closing of a device main body easy. CONSTITUTION:A paper feeding means 14 and a paper ejecting means 21 are disposed in the upper location of a photosensitive drum 1, a developing device 2, and a dielectric belt 8, and further, the device main body 30 is divided and provided so as to open/close along the recording material carrying path composed of carrier guiding plates 15 and ejected paper guiding plates 22.

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 method based on the application of the Carlson process has been widely used for image formation using toner. The principle will be described with reference to FIG. 7 by taking the positive development method used in a copying machine as an example. The apparatus adopting the Carlson process is as shown in FIG.
A photosensitive drum 31 having a photosensitive layer on its surface is provided. Around the photosensitive drum 31, a charger 32, an exposure device 33,
A developing device 34, a transfer device 35, and a cleaner 36 are sequentially arranged. Further, below the photoconductor drum 31, there is provided a conveyance path 37 passing between the photoconductor drum 31 and the transfer device 35, and a fixing device 38 and a pressure roller 39 are provided on the downstream side of the conveyance path 37. And are provided in pressure-contact with each other.

In the above structure, first, the surface of the photosensitive drum 31 is uniformly charged by the charger 32 in a dark place. Next, the exposure device 33 irradiates light to remove the charged electric charge in the exposed portion to form an electrostatic latent image. Next, the electrostatic latent image is charged with the toner 40 charged to the opposite polarity to the charging charge on the photoconductor drum 31 in the developing device 34.
As a result, the visible image is formed by the toner 40. After that, the transfer paper 41 is superposed on this visible image, and the toner image is transferred onto the transfer paper 41 by applying corona discharge from the back side of the transfer paper 41 by the transfer device 35 to give an electric charge of the opposite polarity to the toner 40. .. Transfer paper 4 with the toner image transferred
1 is a fixing device 38 and a pressure roller 39 that pass through a conveyance path 37.
And the heat of the fixing device 38 and the pressure roller 3
The pressure of 9 fixes the toner image as a permanent image.
On the other hand, the residual toner remaining on the photosensitive drum 31 without being transferred to the transfer paper 41 is removed by the cleaner 36.
Then, the process starting from charging by the charger 32 is repeated again, and continuous image formation is performed.

Further, in the electrophotographic apparatus for forming an image by the above-mentioned process, the main body of the apparatus is divided along the transport path 37 and twisted from the viewpoint of maintainability against paper jam in the transport path 37. An auxiliary device (not shown) such as a spring is provided so that it can be opened and closed.

[0005]

However, in the above-mentioned conventional structure for opening and closing the apparatus main body along the transport path 37, the transport path 37 is located below the main constituent members such as the photosensitive drum 31 and the developing device 34. Since they are arranged, the weight of the upper main body with the transport path 37 as a boundary becomes large, which is a great obstacle to the opening and closing of the apparatus main body. Further, since auxiliary devices such as torsion springs must be individually provided so that the main body of the device can be easily opened and closed, the number of parts is increased and the cost is increased accordingly. Further, when the main body of the apparatus is opened, since the photoconductor drum 31 is exposed to the outside, light from the outside hits the photoconductor drum 31, causing light fatigue on the surface of the photoconductor drum 31, and
There is a problem that the surface of the photoconductor drum 31 is scratched or soiled by directly touching the photoconductor drum 31 with the result that the image quality is deteriorated.

[0006]

In order to solve the above-mentioned problems, the electrophotographic apparatus according to claim 1 of the present invention temporarily fixes the toner image on the surface of the photoreceptor, which is developed by the developing device, to the intermediate transfer material. The following means are taken in an electrophotographic apparatus which transfers the toner image transferred to the recording material conveyed by the recording material conveying means to the recording material conveyed by the recording material conveying means.

That is, the recording material conveying means is disposed above the photoconductor, the developing device and the intermediate transfer material, and the apparatus main body is arranged along the recording material conveying path which constitutes the recording material conveying means. It is divided and opened and closed.

In order to solve the above-mentioned 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 photosensitive member is
It is shielded from the outside by the intermediate transfer material and the developing device.

[0010]

According to the structure described in claim 1, the main body of the apparatus is divided along the recording material conveying path of the recording material conveying means arranged above the photoconductor, the developing device and the intermediate transfer material. By being provided so as to be openable and closable, the weight of the upper main body with the recording material conveyance path as a boundary is reduced, and the opening and closing of the apparatus main body is facilitated.

Further, according to the second aspect of the invention, since the photoconductor can be shielded from the outside even when the main body of the apparatus is opened, the surface of the photoconductor is protected from the light, scratches, or dirt from the outside. Therefore, it is possible to avoid deterioration of image quality due to deterioration of the surface of the photoconductor.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The following will describe one embodiment of the present invention with reference to FIGS.

As shown in FIG. 3, the electrophotographic apparatus according to the present embodiment is provided 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 photosensitive drum 1, an exposure device 7 is provided inside the photosensitive drum 1, and a dielectric belt 8 as an intermediate transfer material is provided above the photosensitive drum 1.

As shown in FIG. 4, 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 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 resin such as 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 developing device 2 is operated in accordance with an image pattern signal of a document from an exposure control device (not shown). The light is emitted in the direction of, and the emitted light is focused on the photoconductive layer 1c through the transparent support 1a and the transparent conductive layer 1b of the photosensitive drum 1.

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 a position above 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 configuration 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 serves as a component thereof through 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 members are 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 the recording material conveying means of the present invention, and the conveying guide plates 15 and 15 forming the sheet feeding path and the sheet discharging path. A recording material conveying path is formed by the ejected paper guide plates 22 and 22.

Further, in the electrophotographic apparatus of this embodiment, the main body 30 of the apparatus is divided along the recording material conveying path described above, and at the left and right sides of the paper discharge rollers 25 forming the paper output means 21. By providing the member 26, as shown in FIG. 2, the upper main body 30a with the recording material conveying path as a boundary is provided so as to be openable and closable with respect to the lower main body 30b. In the opened state of the apparatus main body 30, the photosensitive drum 1 arranged on the lower main body 30b side is externally exposed by the dielectric belt 8 located above the photosensitive belt 1 and the developing device 2 located laterally. It is shielded from.

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), so that the paper feed roller 18 is rotated. 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. 4, 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 contacted 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. 5, 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, charges are again injected from the developing sleeve 5b to the photosensitive drum 1 through the conductive toner T. However, before the charges are sufficiently injected, the charges are electrically conductive to the photosensitive drum 1. Since the conductive toner T is separated from the conductive toner T, as shown in FIG. 6, the conductive toner T is subjected to the action of the electric field that acts between the developing sleeve 5b and the surface of the photosensitive drum 1 in the state where the electric charge is injected, so that the conductive toner T of the magnetic roller 5a. 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 is transferred are connected to 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 toner image is transferred and fixed is pushed up by the paper output detection actuator 23 and is discharged from the apparatus through the transfer paper discharge opening by the rotation of the paper discharge roller 25. Then, the paper input detection switch 1
After a predetermined time when the paper input detection signal from 7 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 and the stepping motor 13 is driven. The operation is stopped, and the series of operations as described above is ended.

As described above, in the electrophotographic apparatus of this embodiment, the recording material conveying means for conveying the transfer paper P is arranged above the photosensitive drum 1, the developing device 2 and the dielectric belt 8. Further, the apparatus main body 30 is divided along the recording material conveying path forming the recording material conveying means so as to be opened and closed. Therefore, the upper main body 30a having the recording material conveyance path as a boundary can be configured to be lightweight, so that the apparatus main body 30 can be easily opened and closed, and the maintainability of the apparatus can be improved.

The lower main body 30b of the apparatus main body 30
The photosensitive drum 1 arranged in the above is provided so as to be shielded from the outside by the developing device 2 and the dielectric belt 8 when the main body 30 of the device is open.

For this reason, there is no risk of external light shining on the surface of the photoconductor drum 1, and it is difficult to directly touch the photoconductor drum 1 with a hand. It is possible to avoid scratches and stains, and as a result, it is possible to avoid deterioration of image quality due to deterioration of the surface of the photosensitive drum 1.

[0043]

As described above, in the electrophotographic apparatus according to the first aspect of the present invention, the recording material conveying means is arranged above the photoconductor, the developing device and the intermediate transfer material, and The main body of the apparatus is divided along the recording material conveying path that constitutes the recording material conveying means and is opened and closed.

As a result, the main components such as the photoconductor, the developing device, and the intermediate transfer material can be arranged in the lower main body with the recording material conveying path as a boundary, and the upper main body can be significantly reduced in weight. be able to. Therefore, it is possible to easily open and close the main body of the apparatus and improve the maintainability of the apparatus. Further, along with this, it is not necessary to provide an auxiliary device as in the conventional example, so that it is possible to reduce the number of parts and reduce the cost.

According to a second aspect of the present invention, in the electrophotographic apparatus according to the first aspect, the photosensitive member is shielded from the outside by the intermediate transfer material and the developing device when the main body of the device is opened. is there.

As a result, even when the main body of the apparatus is opened, the surface of the photoconductor can be protected from light, scratches, or dirt from the outside, and consequently deterioration of image quality due to deterioration of the surface of the photoconductor can be avoided. There is an effect that can be.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing various components constituting an electrophotographic apparatus according to an embodiment of the present invention.

FIG. 2 is a vertical cross-sectional view showing a photoconductor drum, a developing device, an exposing unit, and a dielectric belt which constitute the electrophotographic apparatus.

FIG. 3 is a vertical cross-sectional view showing a state where an upper main body of the electrophotographic apparatus is opened with respect to a lower main body.

FIG. 4 is an explanatory diagram showing a state in which the surface of the photosensitive drum is charged by contact with conductive toner.

FIG. 5 is an explanatory diagram showing a state where the surface of the photosensitive drum is neutralized by exposure of an exposure device.

FIG. 6 is an explanatory diagram showing a state in which a toner image is developed on the surface of the photosensitive drum.

FIG. 7 is a vertical cross-sectional view showing an electrophotographic apparatus adopting a Carlson process of a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Photoconductor drum (photoconductor) 2 Development device 8 Dielectric belt (intermediate transfer material) 14 Paper feeding means (recording material conveying means) 15 Conveyance guide plate (recording material conveying path) 21 Paper ejection means (recording material conveying means) 22 Paper ejection guide plate (recording material conveying path) 30 Device body 30a Upper body 30b Lower body P Transfer paper (recording material)

Claims (2)

[Claims] 1. A recording material, wherein a toner image on the surface of a photoconductor, which is developed by a developing device, is once transferred to an intermediate transfer material, and the toner image transferred to the intermediate transfer material is conveyed by a recording material conveying means. In the electrophotographic apparatus for transferring to, the recording material conveying means is disposed above the photoconductor, the developing device, and the intermediate transfer material, and along the recording material conveying path forming the recording material conveying means. An electrophotographic apparatus, wherein the apparatus main body is divided and provided so as to be opened and closed. 2. The electrophotographic apparatus according to claim 1, wherein the photosensitive member is shielded from the outside by an intermediate transfer material and a developing device when the main body of the device is opened.