JP2948992B2 - Image forming apparatus roller and image forming apparatus using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

(Contents) Industrial application field Conventional technology (FIGS. 9 to 10) Problems to be solved by the Invention Means for Solving the Problems (FIG. 1) Action Embodiment (a) Description of Image Forming Apparatus (FIGS. 2 and 3) (b) Description of the first embodiment (FIGS. 4 and 6) (c) Configuration of the second embodiment (FIG. 7) (d) Description of the third embodiment (FIG. 8) (e) Description of other embodiments Effect of the Invention

[0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a roller for an image forming apparatus which applies a voltage to a shaft and contacts an image forming body in an electrophotographic apparatus or the like, and an image forming apparatus using the same.

Image forming apparatuses, such as electrophotographic apparatuses and electrostatic recording apparatuses, which form an electrostatic latent image and develop it to form a visible image are widely used in printing apparatuses, copiers, facsimile machines and the like. And various rollers are used.

For example, in a powder developing device that develops an electrostatic latent image, a charged toner is supplied to a latent image forming surface by a developing roller, and the toner is attached to form a toner image. A transfer roller is also used in the container.

In such an image forming apparatus roller, a voltage is applied and the roller comes into contact with the latent image forming surface. For example, when a one-component non-magnetic toner is used in the developing roller, the toner is pressed against the latent image forming surface, and the charged thin layer toner is conveyed to the latent image forming surface. It is necessary to apply a bias voltage to move to the electrostatic latent image on the surface and develop it. For this reason, it has conductivity and is in contact with the latent image forming surface during development. Therefore, it is necessary to have elasticity.

[0006] For this reason, it is desirable that such a roller has a moderate resistance because of applying a bias voltage and is soft because it is in contact with the roller.

[0007]

2. Description of the Related Art FIGS. 9 and 10 are explanatory diagrams (part 1) and (part 2) of a conventional technology. In the formation of the roller for an image forming apparatus having such conductivity and elasticity, a conductive filler is dispersed in a base material, or the base material surface is coated with a conductive filler and impregnated to have conductivity. That is usually done.

For example, taking a developing roller as an example, a conductive porous polyurethane roller having a large number of pores of several tens of microns or less is useful. The pore diameter is smaller than that of a sponge roller, and the toner is not clogged and stable. Can be transported to

If the conductive resistance of the roller is too low, leakage occurs at the scratched portion of the photoreceptor, causing a problem such as damage to the roller. Since the repetition is performed in the portion, the escape area is lost, the toner charge amount on the roller increases, and the non-print portion also develops, so-called fog occurs.

For this reason, the roller needs to have an appropriate resistance, for example, from 10 6 to 10 7 ohm · cm.
Is appropriate. Explaining the production of the conductive porous polyurethane roller, a conductive filler such as black carbon, polyurethane, and a water-soluble defoaming substance are mixed, and as shown in FIG. A shaped polyurethane molded article 90 is formed.

At this time, as shown in FIG. 10 (C), the compounding speed of the surface exposed to the air is high, and the conductive filler and the water-soluble defoaming material are urethane crystals 1 to 5 which are hard to disperse.
A skin layer (high resistance layer) 93 of about a micron is formed on the outer surface and the inner surface of the polyurethane molded product 90.

Next, as shown in FIG. 9 (B), the polyurethane molded article 90 is put into a melting tank, and the water-soluble defoaming material is melted and defoamed. Form. Then, as shown in FIG. 9C, the polyurethane molded article 90 is cut into a predetermined length of a roller to form a conductive porous polyurethane roller 91. At this time, no skin layer is formed on the cut surface. .

Next, as shown in FIG. 10A, a metal shaft 92 is tubed at the center of the conductive porous polyurethane roller 91. In this state, FIG.
As shown in FIG.
As shown in FIG. 10 (B), since the skin layer 93 without micropores is present on the outer surface of FIG.
The outer surface of the conductive porous polyurethane roller 91 is polished with a polishing tool, and the skin layer 93 on the outer surface is peeled off to complete the polishing.

Therefore, a skin layer 93 which is a high resistance layer remains on the inner surface of the conductive porous polyurethane roller 91. As described above, the skin layer remains on the inner surface of the roller in a conductive elastic roller in which a conductive filler is dispersed in another base material. The same applies to high quality rubber materials.

In the method of impregnating the base material with the conductive filler, the conductive filler does not penetrate to the inner surface of the roller, the high resistance layer exists on the inner surface, and the end surface and the outer surface have low resistance.

[0016]

However, the prior art has the following problems. On the inner surface of the conductive elastic roller 91 which is in contact with the metal shaft 92,
A high-resistance skin layer 93 remains. The skin layer 93 has poor dispersion of the conductive filler, a high resistance value, and an unstable thickness. Therefore, when a potential is applied to the metal shaft 92, the resistance of the entire roller is reduced. The value is affected by variations in the thickness and the resistance value of the skin layer 93, the effective potential varies, and the above-described image forming action fluctuates.

It is conceivable to control the thickness and the resistance value of the skin layer 93 so that the resistance value after being formed on the roller becomes a desired value. However, the characteristics of the skin layer 93 are controlled. Because it is difficult, a stable product cannot be obtained in production, and if a roller having a desired resistance value is obtained by sorting or the like, the yield becomes extremely poor and the cost increases.

Similarly, in the case where the base material is impregnated with the conductive filler, when a voltage is applied, current concentrates on a portion of the end face impregnated with the conductive filler, and the portion is burned.

Accordingly, the present invention provides a roller for an image forming apparatus capable of obtaining a roller having a desired resistance value irrespective of the thickness and resistance value of a high resistance layer on the inner surface of a conductive elastic roller, and an image using the same. It is an object to provide a forming device.

[0020]

FIG. 1 is a diagram illustrating the principle of the present invention. Claim 1 of the present invention, as shown in FIG.
Conductive elastic roller 91 having a conductive filler dispersed in a base material
A conductive shaft 92 is inserted at the center of the image forming device, a voltage is applied to the conductive shaft 92, and a conductive electrode 94 is inserted into the conductive shaft 92 in an image forming apparatus roller that comes into contact with the image forming body 40; The conductive shaft 92 and the conductive elastic roller 91 are electrically connected to an end surface of the conductive elastic roller 91 with a conductive adhesive 96 or by thermal bonding.

According to a second aspect of the present invention, as shown in FIG. 1B, a conductive shaft 92 is inserted into the center of a conductive elastic roller 91 in which a conductive filler is dispersed in a base material. In a roller for an image forming apparatus that applies a voltage to the shaft 92 and comes into contact with the image forming body 40, the conductive elastic roller 91
High resistance layer 9 on the conductive shaft 92 side of conductive elastic roller 91
3 is characterized by being heated and melted.

According to a third aspect of the present invention, as shown in FIG. 1B, a conductive shaft 92 is inserted into the center of a conductive elastic roller 91 in which a conductive filler is dispersed in a base material. In a roller for an image forming apparatus that applies a voltage to the shaft 92 and comes into contact with the image forming body 40, the conductive elastic roller 91
High resistance layer 9 on the conductive shaft 92 side of conductive elastic roller 91
3 is characterized by being destroyed by energization.

According to a fourth aspect of the present invention, in the first, second or third aspect, the conductive elastic roller 91 is obtained by dispersing the conductive filler in a porous elastic material.

According to a fifth aspect of the present invention, in the first or second or third or fourth aspect, the conductive elastic roller 91 is a developing roller that transports toner and develops the latent image on the image forming body 40. There is a feature.

According to a sixth aspect of the present invention, in the first or second or third or fourth aspect, the conductive elastic roller 91 is a transfer roller for transferring the toner of the image forming body 40 to a medium. I do.

According to a seventh aspect of the present invention, the roller for an image forming apparatus according to the first, second, third or fourth aspect is used as a developing roller to transport toner to an image forming body 40 on which an electrostatic latent image is formed. A developing bias voltage is applied to the conductive shaft 92 of the roller for the image forming apparatus to develop the electrostatic latent image on the image forming body 40 with toner.

[0027]

According to the first aspect of the present invention, a conductive electrode 94 for electrically connecting the conductive shaft 92 to the end surface of the conductive elastic roller 91 is provided, and the conductive elastic roller 91 has an end surface portion without the high resistance layer 93. The high resistance layer 9
3 can be prevented from affecting the roller resistance value, and the conductive electrode 94 is bonded to the end surface of the conductive elastic roller 91 by the conductive adhesive 96 or heat, so that the connection area becomes constant and the electrical resistance can be stabilized. .

According to the second aspect of the present invention, the high resistance layer 93 on the inner surface of the conductive elastic roller 91 is melted by heating.
In order to reduce the electric resistance by allowing the conductive filler to be dispersed in the roller, the effect of the high resistance layer 93 on the roller resistance can be prevented.

According to the third aspect of the present invention, the high resistance layer 93 on the inner surface of the conductive elastic roller 91 is destroyed by current, and
Since 3 is omitted, it is possible to prevent the high resistance layer 93 from affecting the roller resistance value.

According to the fourth aspect of the present invention, since the conductive elastic roller 91 is formed by dispersing the conductive filler in a porous elastic material, a roller having sufficient elasticity and conductivity can be obtained.

In the fifth and seventh aspects of the present invention, since the conductive elastic roller 91 is applied to the developing roller, the development with the one-component non-magnetic toner can be stably performed. According to claim 6 of the present invention, since the conductive elastic roller 91 is applied to the transfer roller, the toner can be stably transferred to the medium without toner clogging.

[0032]

【Example】

(a) Description of Image Forming Apparatus FIG. 2 is a cross-sectional view of an image forming apparatus according to an embodiment of the present invention, and FIG. 3 is a configuration diagram of a process unit according to an embodiment of the present invention, showing an electrophotographic printer.

In the sectional view of the apparatus shown in FIG. 2, reference numeral 2 denotes a process unit, which is provided above a paper cassette 12 for accommodating paper, which will be described later with reference to FIG. A thermal fixing device 6 for transporting the paper from the cassette 12 to the stacker 14 by a U-shaped path is used to fix a toner image on the paper by being sandwiched between a heat roller 60 and a backup roller 61. A cleaning roller 62 for removing toner adhered to the roller 60 is provided.

Reference numeral 7 denotes an optical unit, which scans the light of a semiconductor laser driven by image information with a polygon mirror and passes over a developing unit 5 as indicated by a dotted arrow in FIG. Reference numeral 8 denotes a paper separation unit, which has a discharge electrode, discharges a charge having a polarity opposite to the paper back potential to the back of the transferred paper, discharges the back of the paper, and discharges the paper. Is separated from the photosensitive drum 40.

Numeral 30 denotes a pickup roller which picks up the paper in the paper cassette 12, 31 denotes a registration roller, which conveys the paper picked up by the pick-up roller 30 with its leading edge aligned, and 32 denotes a manual feed guide. Opening to the right side of the drawing, the manual feed paper is guided to the manual feed roller 33. Reference numeral 33 denotes a manual feed roller, which conveys the paper inserted from the manual feed guide 32 to the process unit 2.

Reference numeral 34 denotes a cover shaft, which serves as a rotation shaft of the front cover 10 which is opened and closed to open the transport path 3, and 36 denotes a discharge roller, which discharges the paper passing through the heat fixing unit 6 to the stacker 14. It is for doing.

In the configuration diagram of the process unit shown in FIG. 3, the process unit 2 includes a drum cartridge 4 and
The developing device 5 includes a drum cartridge 4
Is attached by a pin (not shown), and can be removed from the drum cartridge 4 by removing the pin.

The structure of the drum cartridge 4 will be described. A photosensitive drum 40 is formed by forming an organic photosensitive material layer (OPC or the like) on the surface of a cylindrical base such as aluminum, and rotates counterclockwise as shown in the figure. What is done, 41
Reference numeral denotes a charging roller, which is formed of a conductive rotating brush charger in which conductive rayon fibers are woven into a core metal and planted, and uniformly charges the photosensitive drum 40 to about -600V.

Reference numeral 42 denotes a transfer roller, which is provided on the drum cartridge 4 and is made of a conductive porous elastic material, for example, a porous foamed polyurethane sponge material, is pressed against the photosensitive drum 40, and has a transfer voltage applied to the shaft 42a. Is applied to transfer the toner image on the photosensitive drum 40 to paper,
Reference numeral 43 denotes a waste toner box, which scrapes and stores residual toner on the photosensitive drum 40 with a scraping blade 44; 45, a handle for holding the drum cartridge 4 by hand; and 46, a roller cover. , For protecting the transfer roller 42.

Reference numeral 50 denotes a developing roller, which is made of a conductive porous elastic material, for example, a porous foamed polyurethane sponge material, and holds a magnetic one-component toner as a developer with a holding force on its surface, and The photosensitive drum 40 is conveyed to the photosensitive drum 40 so as to have a predetermined nip width, and a developing bias voltage of -300 V is applied to the shaft 50a.

Reference numeral 51 denotes a layer thickness regulating blade which regulates the layer thickness of the toner adhered to the developing roller 50 to a predetermined thickness, and is constituted by a 0.1 mm thick stainless steel plate.
When pressed against the developing roller 50, a negative voltage of, for example, −400 V is applied, and when the toner layer thickness is regulated, a negative charge is injected into the toner, and the toner is forcibly charged negatively.
It stably charges the toner.

A reset roller 52 is made of a conductive sponge material, is brought into contact with the developing roller 50, is rotated in the same direction as the developing roller 50, is supplied with a bias voltage of -400 V, and This serves to scrape off the toner from the developing roller 50 and to supply the toner to the developing roller 50 on the left side of the drawing.

Reference numerals 53 and 54 denote paddle rollers which rotate and stir and charge the non-magnetic one-component toner in the developing device 5 and transport the toner toward the reset roller 52. Reference numeral 55 denotes a cassette housing portion. Yes, toner cassette 56
It is for accommodating.

Reference numeral 56 denotes a toner cassette, which contains a one-component non-magnetic toner and is set in a detachable manner in a cassette storage portion 55. Reference numeral 57 denotes a toner supply lever, which is provided in the toner cassette 56 and rotates. The toner supply unit 58 supplies the toner in the toner cassette 56 into the developing unit 5. 58 is a handle provided on the toner cassette 56 and used for holding the toner cassette 56 by hand. 59 is a paper guide rib. In addition, the sheet guides the sheet together with the roller cover 46 between the photosensitive drum 40 and the transfer roller 42.

The operation of this printer will be described with reference to FIGS. 2 and 3. The paper in the paper cassette 12 is picked up by a pickup roller 30, abutted against a registration roller 31, the leading ends thereof are aligned by the registration roller 31, and
The character is conveyed along the character conveying path 3 toward the photosensitive drum 40.

On the other hand, when the sheet is picked by the registration roller 31, the image exposure of the photosensitive drum 40 by the optical unit 7 is started, and the potential of the image exposure portion of the photosensitive drum 40 charged to -600V by the charging roller 41 is started. Becomes zero, and an electrostatic latent image corresponding to the image is formed.

In the developing device 5, the developing roller 50
Since the bias voltage of 0 V is applied, the negatively charged toner adheres to the image exposure portion of the photosensitive drum 40 where the potential is zero, and a toner image is formed.

On the sheet to be transported, the toner image on the photosensitive drum 40 is transferred by the transfer roller 42 by electrostatic force and pressure, and the sheet electrostatically attracted to the photosensitive drum 40 is
The electric charge on the back surface of the paper is removed by the charge supplied from the paper separation unit 8, and the paper is separated from the photosensitive drum 40.

The separated sheet is sent to the heat fixing unit 6, the toner image on the sheet is thermally fixed by the heat roller 60 of the heat fixing unit 6, and is discharged to the stacker 14 by the discharge roller 36.

Similarly, the paper inserted with the manual feed guide 32 turned down is moved by the manual feed roller 33 to the photosensitive drum 40.
The toner image on the photosensitive drum 40 is transferred by the transfer roller 42 by electrostatic force and pressure, and the sheet electrostatically attracted to the photosensitive drum 40 is transferred to the photosensitive drum 40 by the charge supplied by the sheet separating unit 8. The toner image on the sheet is thermally fixed by the heat roller 60 of the heat fixing device 6, and is discharged to the stacker 14 by the discharge roller 36.

The sheet on which the toner image has been transferred is fixed by a heat roller fixing unit 24 and discharged to a stacker 26 by a discharge roller 25. In this image forming apparatus, since charging, development, and transfer are performed by rollers, a corona discharger is not used, so that an image can be formed without generating ozone that affects the human body.

In this developing device 5, the developing roller 50 is composed of a conductive shaft 50a (92) to which a developing potential is applied, and a conductive porous polyurethane roller (for example, Rubicel (trade name) manufactured by Toyo Polymer Co., Ltd.) 91. And the photosensitive drum 4
0, the one-component non-magnetic toner is charged by the hole of the conductive porous polyurethane roller 91 and the blade 51, and is conveyed to the photosensitive drum 40 while being held in the hole of the conductive porous polyurethane roller 91. And development.

This conductive porous polyurethane roller 91
The hole can be supplied with toner stably without being clogged by the toner. (b) Description of First Embodiment FIG. 4 is an explanatory view of a first embodiment of the present invention, FIG. 5 is an explanatory view of a previously proposed comparative example of the present invention, and FIG. 6 is a comparative example of the present invention. FIG. 9 is a characteristic diagram already proposed.

In this example, the skin layer 93 is not formed on the end surface of the conductive porous polyurethane roller 91 in the configuration in which the metal shaft 92 is provided at the center of the conductive porous polyurethane roller 91 of FIG. Utilizing that
The continuity between the metal shaft 92 and the conductive porous polyurethane roller 91 is established.

For this reason, as shown in FIG. 4A, a stainless disk-shaped metal contact 94 having a thickness of 0.2 mm is formed.
Is fitted to a metal shaft 92, and the disk portion of the metal contact 94 is moved by the spring portion 95 of the metal contact 94 so that the conductive porous polyurethane roller 91 having an Asker C hardness of 20 ° is formed.
(Made by Toyo Polymer Co., Ltd., trade name: Rubicell) and connected to the metal shaft 92 by the spring part 95.

Then, as shown in FIG. 4B, the metal contact 94 is adhered to the end face of the conductive porous polyurethane roller 91 by the conductive adhesive 96. As a result, the metal contact 94 is fitted into and adhered to the metal shaft 92 to form the conductive porous polyurethane roller 91.
And the metal shaft 92 can be electrically connected, and the skin layer 93
It does not affect the resistance value of the developing roller 50.

On the other hand, 1991 patent application No. 28976
In the connection structure proposed in the specification No. 8 (filed on Nov. 6, 1991), as shown in FIG. 5A, a pair of needle-like projections 94a are provided on a disk-shaped metal contact 94, and The metal contact 94 is fitted on the metal shaft 92, and the disc surface of the metal contact 94 is pressed against the end surface of the conductive porous polyurethane roller 91 by the spring portion 95 of the metal contact 94, and at the same time, as shown in FIGS. As shown in
The needle-like protrusion 94 a is pushed into the end surface of the conductive porous polyurethane roller 91, and the metal shaft 92 is
Is to connect.

FIG. 6 shows the relationship between the length l of the conductive portion of the metal contact 94 (the length of the needle of the needle-shaped projection) and the resistance value of the developing roller in this configuration. from this result,
When the length l of the needle-like projection 94a of the metal contact 94 is “0”, that is, when there is no needle, the resistance value is 10 to the sixth power.
Even if the length of the needle is long, for example, l = 6 mm, the resistance value is in the range of 10 6 to 1 Ω · cm.
The resistance value of the developing roller 50 was not stable even when the length of the conductive portion was changed.

This is probably because the connection between the metal contact 94 and the conductive porous polyurethane roller 91 is not constant because the connection is made by needle-like projections.

On the other hand, in the present embodiment, the metal contact 94 is adhered to the end face of the conductive porous polyurethane roller 91 by the conductive adhesive 96, so that the connection is secure and constant. The resistance value was as small as 10 6 to 10 7 ohm-cm.

For this reason, when used in the non-magnetic one-component developing device shown in FIG. 3, the developing bias voltage was applied constantly, the printing density became constant in each developing device, and the occurrence of fog could be prevented.

The adhesion area S (square mm) and the metal shaft 92
When the relationship between the current I (microamperes) flowing between the conductive porous polyurethane roller 91 and the conductive porous polyurethane roller 91 was examined,
When I / S was 0.01 or 0.05, no fogging occurred, and when I / S exceeded 0.1, fogging occurred.

This means that if the adhesion area is small with respect to the current I, the conduction is not good, and the conductive porous polyurethane roller 91 is charged up by the charge of the toner.
It is considered that the potential dropped to -400 V or less.

Accordingly, the bonding area S is determined by the current I flowing between the metal shaft 92 and the conductive porous polyurethane roller 91.
On the other hand, it was found that when the ratio was 10 times or more, good developing characteristics were exhibited.

In this example, when the metal contact 94 is bonded to the end surface of the conductive porous polyurethane roller 91,
Although the conductive adhesive 96 is used, the same effect can be obtained by thermal bonding.

Even when the base material is impregnated with a conductive filler, the current at the roller end face may concentrate on the low resistance part by bonding the metal contact 94 to the low resistance part on the end face of the roller. Since it is eliminated, burnout of the roller can be prevented.

(C) Description of the Second Embodiment FIG. 7 is an explanatory diagram of the second embodiment of the present invention. In this embodiment, in the configuration in which the metal shaft 92 is provided at the center of the conductive porous polyurethane roller 91 shown in FIG. 10B, the skin layer 93 on the inner surface of the conductive porous polyurethane roller 91 has a low resistance. is there.

For this reason, as shown in FIGS. 7A and 7B, a conductive porous polyurethane roller 91 and a metal shaft 92 are provided.
When a heating wire (Nichrome wire) 98 is inserted between the heating wires and a heating power supply 97 is applied to the heating wire 98 to partially heat the inner surface high-resistance layer 93, the heating causes the high-resistance layer 93 to be heated.
Is melted, and the conductive filler therein is easily dispersed, penetrates into the high-resistance layer 93 and lowers the resistance value of the high-resistance layer 93, and the high-resistance layer 93 has a low resistance.

As a result, a part of the high resistance layer 93 on the inner surface of the conductive porous polyurethane roller 91 becomes a low resistance part, and a part of the high resistance layer 93 is broken. Conduction is obtained, and stable electric resistance is obtained.

(D) Description of Third Embodiment FIG. 8 is an explanatory diagram of a third embodiment of the present invention. In this embodiment, in the configuration in which the metal shaft 92 is provided at the center of the conductive porous polyurethane roller 91 of FIG. 10B, the skin layer 93 on the inner surface of the conductive porous polyurethane roller 91 is electrically broken. .

For this reason, as shown in FIG. 8, a metal electrode 99 is provided around a conductive porous polyurethane roller 91 and is brought into contact therewith, and a high voltage (for example, When 1 kV is applied, high heat is generated in the high resistance layer 93 of the conductive porous polyurethane roller 91, and the high resistance layer 93 is broken.

As a result, the high-resistance layer 93 on the inner surface of the conductive porous polyurethane roller 91 has been broken, and conduction with the metal shaft 92 can be obtained, and stable electric resistance can be obtained. (e) Description of Other Embodiments In addition to the above-described embodiments, the present invention can be modified as follows.

Although the printing apparatus has been described as an electrophotographic printing apparatus, it can be applied to an electrostatic recording apparatus, and the developer is described as a one-component developer. Can also be applied.

Although the printer has been described, the present invention can be applied to other image forming apparatuses such as a copying machine and a facsimile. Although described with reference to the example of the developing roller, the present invention can also be applied to the collecting roller and the transfer roller 42 as shown in FIGS.

Although the conductive member has been described as a metal contact, for example, a conductive contact may be used, and the conductive shaft is not limited to the metal shaft, and another conductive shaft may be used. Although the conductive elastic roller has been described as a conductive porous polyurethane roller, the present invention can be applied to an elastic roller using another conductive filler such as a conductive urethane rubber roller and a conductive silicone rubber roller.

The present invention has been described with reference to the embodiments.
Various modifications are possible within the scope of the present invention, and these are not excluded from the scope of the present invention.

[0077]

As described above, according to the present invention,
The following effects are obtained. Because the conductive electrode is connected to the end face of the conductive elastic roller having the high resistance layer on the inner surface and the conductive shaft by bonding or heat bonding, or the inner skin layer of the conductive elastic roller having the high resistance layer on the inner surface is heated and melted. Or, because of the provision of a part that has been destructed by electricity, conduction between the conductive elastic roller and the conductive shaft can be established, and the effect of the inner surface high resistance layer on the roller resistance value can be eliminated, and the resistance value is stable and constant. Can be kept in
The image forming action by the applied potential can be ensured.

Since it is not necessary to manage the skin layer in the production, there is no need for sorting or the like, and the production becomes easy,
Can be provided at low cost.

[Brief description of the drawings]

FIG. 1 is a principle diagram of the present invention.

FIG. 2 is a sectional view of an image forming apparatus according to an embodiment of the present invention.

FIG. 3 is a configuration diagram of a process unit according to an embodiment of the present invention.

FIG. 4 is an explanatory view of a first embodiment of the present invention.

FIG. 5 is an explanatory diagram of an already proposed proposal as a comparative example of the present invention.

FIG. 6 is a characteristic diagram of a proposed device serving as a comparative example of the present invention.

FIG. 7 is an explanatory view of a second embodiment of the present invention.

FIG. 8 is an explanatory view of a third embodiment of the present invention.

FIG. 9 is an explanatory diagram (part 1) of a conventional technique.

FIG. 10 is an explanatory diagram (part 2) of a conventional technique.

[Explanation of symbols]

 Reference Signs List 40 photosensitive drum (image forming body) 42 transfer roller 5 developing device 50 developing roller 91 conductive porous polyurethane roller 92 conductive shaft 93 skin layer 94 metal contact (conductive electrode) 95 spring portion 96 conductive adhesive 97 power supply 98 heating wire 99 metal electrode

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G03G 15/08-15/09 101 G03G 15/16

Claims (7)

(57) [Claims] 1. A conductive shaft (92) is inserted into the center of a conductive elastic roller (91) in which a conductive filler is dispersed in a base material, and a voltage is applied to the conductive shaft (92) to form an image. In the roller for an image forming apparatus which comes into contact with the formed body (40), the conductive electrode (94) is bonded to the end face portion of the conductive elastic roller (91) with a conductive adhesive (96) or by thermal bonding. The conductive shaft (92) and the conductive elastic roller (91)
A roller for an image forming apparatus, which is electrically connected to the roller. 2. A conductive shaft (92) is inserted into the center of a conductive elastic roller (91) in which a conductive filler is dispersed in a substrate, and a voltage is applied to the conductive shaft (92) to form an image. In the roller for an image forming apparatus which comes into contact with the formed body (40), the conductive elastic roller (91) heats the high resistance layer (93) on the conductive shaft (92) side of the conductive elastic roller (91). A roller for an image forming apparatus, which is melted. 3. A conductive shaft (92) is inserted into the center of a conductive elastic roller (91) in which a conductive filler is dispersed in a substrate, and a voltage is applied to the conductive shaft (92) to form an image. In the roller for an image forming apparatus which comes into contact with the formed body (40), the conductive elastic roller (91) energizes the high resistance layer (93) on the conductive shaft (92) side of the conductive elastic roller (91). A roller for an image forming apparatus, which is broken. 4. The roller for an image forming apparatus according to claim 1, wherein the conductive elastic roller is formed by dispersing the conductive filler in a porous elastic material. 5. The image forming apparatus according to claim 1, wherein the conductive elastic roller is a developing roller that conveys toner and develops a latent image on the image forming body. Or the roller for image forming apparatus of 4. 6. The image forming apparatus according to claim 1, wherein said conductive elastic roller is a transfer roller for transferring toner of said image forming body to a medium. Roller for equipment. 7. The image forming apparatus according to claim 1, wherein the toner is transported to an image forming body on which an electrostatic latent image is formed, using the roller for an image forming apparatus as a developing roller.
An image forming apparatus, wherein a developing bias voltage is applied to a conductive shaft (92) of the image forming apparatus roller to develop the electrostatic latent image of the image forming body (40) with toner.