JP3288879B2 - Image forming device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001] The present invention is related to <br/> the assembling method of an image forming apparatus, particularly, an image forming apparatus using a contact type charging device
It relates to the target assembly method .

[0002]

2. Description of the Related Art In general, in an electrophotographic system, which is one of image forming systems, an electrostatic latent image corresponding to a document image is formed on a photosensitive member as a latent image carrier by exposure, and the electrostatic latent image is formed. What is processed with a visible image by a developer is transferred to a transfer paper to obtain a copy.

[0003] The electrophotographic system is frequently used in copiers, printers, facsimile machines and the like.

In this electrophotographic method, a charging step of uniformly charging a photosensitive member is performed before an exposure step of an original image.

Conventionally, as a charging method used in the charging step, there is a non-contact method using corona discharge. This method has been required to be replaced because of the large amount of electric power consumed and the harmfulness of ozone generated by discharge.

In recent years, instead of the non-contact charging method, in recent years, a conductive member such as a rubber roller mixed with a conductive material such as carbon has been brought into contact with the photoreceptor to generate a DC voltage or a DC and AC. And a contact charging system in which charging is performed by applying a superimposed voltage.

[0007] The contact charging system has advantages such as lower power consumption and no generation of ozone as compared with the non-contact charging system.

In the contact charging method, it is important to make uniform contact between the photosensitive member and the charging roller that contacts the photosensitive member in order to prevent uneven charging.

One of the causes of the uneven charging is the adhesion of impurities to the surface of the charging member used in the contact charging system. As impurities, extraneous substances such as surplus toner and paper powder remaining on the photoconductor correspond.

Conventionally, as a method of removing impurities from the surface of the photoconductor, there is a method of cleaning the surface of the photoconductor after image transfer using a scraping member such as a cleaning blade. In this method using a cleaning blade, after assembling the cleaning blade and the photoreceptor, if the cleaning blade is used for the first time to remove impurities from the photoreceptor, the coefficient of friction between the two is considered. Is very high. For this reason, when the photosensitive member is moved for the first time, a phenomenon may occur in which the cleaning blade is dragged by the movement of the photosensitive member and turned up.

Conventionally, a lubricant such as polyvinylidene fluoride resin powder is applied to the surface of a cleaning blade in order to reduce the coefficient of friction between the cleaning blade and the photosensitive member and prevent the cleaning blade from being dragged. To be done.

However, when the above-mentioned lubricant is used, the lubricant falls off and adheres to the photoreceptor, and the adhered lubricant adheres to the charging roller in contact with the photoreceptor. There is a problem that charging unevenness occurs. When charging unevenness occurs, uniform charging on the photoreceptor is not performed, so that a defective image in which a part of the formed image is missing is obtained.

In particular, in recent years, it has been proposed to arrange a photosensitive member, a charging roller and a cleaning blade in one unit to constitute a process cartridge so as to facilitate maintenance and the like. However, when the cartridge is incorporated into the image forming apparatus, or when the photosensitive member is started to move, there is a possibility that the lubricant may drop onto the photosensitive member due to a shock.

In order to prevent a lubricant from adhering to a charging member such as a photoreceptor or a charging roller, a cleaning blade and a photosensitive blade are stored in the image forming apparatus during storage until the process cartridge is incorporated. It has been proposed to arrange a paper that can be pulled out between the body and the body as a shielding member (for example, Japanese Patent Laid-Open No. 4-140770).

[0015]

However, the process card
In the case where the cleaning blade is replaced in the process cartridge after the cartridge is incorporated in the image forming apparatus, the cleaning blade A is applied to the cleaning blade A as shown in FIG. There is a high risk that the lubricant B falls and the dropped lubricant B reaches a charging device (not shown) located downstream in the moving direction of the photoconductor B in accordance with the movement of the photoconductor C.

The polyvinylidene fluoride used as a lubricant is easily aggregated and often forms a large lump, so that when it adheres to a charging member, the range in which charging unevenness occurs becomes large, thereby causing image defects. There was a problem that the part became large.

SUMMARY OF THE INVENTION An object of the present invention is to prevent the occurrence of a defective image by preventing adhesion of a lubricant to a charging member in view of a problem in the above-described conventional image forming apparatus, particularly, in a process cartridge provided in the apparatus. It is an object of the present invention to provide a method of assembling an image forming apparatus capable of performing the following.

[0018]

In order to achieve the above object, the present invention is directed to a latent image carrier having a photoconductive layer on its surface, and a photoconductive layer which is in contact with the latent image carrier. a contact charging device for uniformly charging the layer, the image bearing member to clean the upper image bearing member an electrostatic latent image formed on said image bearing member after transferring the image processed visual image Contact with
Set of image forming apparatus provided with a process cartridge disposed a releasing capable provided blade in one unit
In standing method, the image bearing only when the upper Symbol process cartridge is incorporated initially into the image forming apparatus
The body the cleaning blade upon the application of the low friction lubricant in a portion of the surface of the is brought into contact with the coating position of the low-friction lubricant for the latent image carrier take-the low friction lubricant
Up can, after scraping the end of the low friction lubricant, and the contact charging device is characterized in that incorporated in the process cartridge.

[0019]

[0020]

[0021]

According to the first aspect of the present invention, only when the process cartridge is first installed in the image forming apparatus.
Applying a low friction lubricant in a portion of the surface of the latent image bearing member
And then apply the applied low friction lubricant to the cleaning
After contacting and detaching the blade,
Installed in the process cartridge to contact the latent image carrier
Is obtained. For this reason, cleaning blades
Is cleaned because low friction lubricant is not applied
Lubricant for low friction does not fall from the blade onto the latent image carrier.
The contact charging device can be connected to the latent image carrier.
Carry latent image by cleaning blade when touching
Contact because low friction lubricant is scraped off the body surface
The low friction lubricant does not adhere to the charging device.

[0022]

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to illustrated embodiments.

FIG. 1 is a schematic diagram for explaining a main configuration of an image forming apparatus according to the present invention.

FIG. 1 shows a copying machine 10 as one of the image forming apparatuses. The copying machine 10 includes a photosensitive drum 11 as a latent image carrier.

The photosensitive drum 11 has a photoconductive layer made of an organic material such as OPC on its surface, and can rotate in the direction of the arrow.

A charging device 1 for performing an image forming process along the rotation direction is provided around the photosensitive drum 11.
2, an exposure device 13, a developing device 14, a transfer device 15, and a cleaning device 16 are arranged.

In the drawing, reference numeral 17 denotes an exposure lamp before transfer,
Numeral 8 denotes a quenching lamp for static elimination.
In the vicinity of the photosensitive drum 11, the photosensitive drum 11
A paper feeding device 20 including a registration roller 19 for feeding the transfer paper S toward a nip portion between the transfer device 15 and the transfer device 15 is provided.

The charging device 12 is composed of a conductive roller which can rotate while being in contact with the photoconductive layer of the photoreceptor drum 11, and is connected to a high voltage power supply 12A to supply DC voltage or DC and AC. Is applied to uniformly charge the photoconductive layer.

Exposure device 13 has a plurality of mirrors and an imaging lens (not shown) for forming an optical path for imaging reflected light from a document on a document table (not shown) on a photoconductive layer. Thus, an electrostatic latent image corresponding to the original image is formed on the photoconductive layer. In the present embodiment, the negative charge disappears in the photoconductive layer due to the intensity of the reflected light, and the portion where the charge remains remains is formed as an electrostatic latent image.

As the developing device 14, a magnetic brush developing device having a well-known structure is used, and the magnetic developer carried and conveyed by the developing sleeve 14A comes into contact with the electrostatic latent image on the photoconductive layer, so that the electrostatic latent image is formed. Is performed.

The pre-transfer exposure lamp 17 is used so as not to lower the transfer efficiency with respect to environmental changes.

The transfer device 15 includes a transfer belt 15A wound around a pair of pulleys and a transfer bias roller 15B.
And a transfer / contact mechanism 15C for the transfer belt 15A.

In the transfer device 15, the registration timing is set by the registration roller 19,
The transfer paper S fed from 0 is conveyed while being pinched by a nip formed between the transfer paper S and the surface of the photoconductive layer of the photosensitive drum 11, and the bias voltage from the transfer bias roller 15B via the high voltage power supply 15B1 is applied. By applying the visible light, the visible image carried on the photoconductive layer is transferred to the transfer paper S.

The transfer belt 15A has a low friction lubricating layer made of fluorine (polyvinylidene fluoride) formed on the surface thereof.
Although separated from the first photoconductive layer, at the time of transfer, the contact / separation mechanism 15C is displaced toward the photosensitive drum 11 by the solenoid 15C2 whose operation is controlled by the control plate 15C1. Such a configuration that comes into contact with the transfer belt 15A only at the time of transfer is similarly provided on the transfer bias roller 15B and the electrode plate 15E described later. The toner and transfer paper fibers attached to the transfer belt 15A are removed by the cleaning blade 15D. The electrode plate denoted by reference numeral 15E is provided to stabilize the current flowing from the transfer bias roller 15B to the photoconductor side and stabilize the transfer performance.

The transfer paper S to which the visible image on the photoconductive layer has been transferred by the transfer device 15 is conveyed by the transfer belt 15A, brought to the fixing roller 21, and discharged to a discharge tray (not shown).

The cleaning device 16 includes the photosensitive drum 1
Cleaning blade 16A contacting one photoconductive layer
And a transport screw 16B for collecting excess toner on the photoconductive layer scraped off by the cleaning blade 16A toward the developing device 14.

The cleaning blade 16A is made of polyurethane rubber whose surface has been subjected to Teflon coating to reduce the friction coefficient of the surface, and scrapes off excess toner and paper dust remaining on the photosensitive drum. It has become.

The photosensitive drum 11, the charging device 12, and the cleaning device 16 are arranged in a process cartridge 22 composed of one unit.

FIG. 2 is a schematic diagram showing the internal configuration of the process cartridge 22. In FIG.
The cartridge 22 includes a housing in which openings 22A and 22B are formed at positions where the photosensitive drum 1 faces the developing device 14 and positions where the photosensitive drum 1 faces the transfer device 15, respectively.

As shown in FIG. 3, the charging device 12 is detachably mounted on the upper wall of the process cartridge 22, and can be removed at the time of maintenance or replacement.

The cleaning blade 16A of the cleaning device 16 is provided so as to be able to contact and separate from the photosensitive drum 11. Therefore, a swingable bracket 24 is provided inside the process cartridge 22 with the support shaft 23 as a base end, and a cleaning bracket is provided at the tip of a support piece 25 attached to the bracket 24.
16A is attached.

The bracket 24 swings on the support shaft 23 as a fulcrum. The tension spring 26 disposed on the lower surface of the swinging end imparts the rotation behavior in the counterclockwise direction in the figure. ing. With this habit,
The leading end of the blade 16A can be brought into contact with the surface of the photosensitive drum 11.

The bracket 2 has a handle 2 projecting outward from a window 22C formed in the process cartridge 22.
4A, the cleaning blade 16A can be separated from the surface of the photosensitive drum 11 by rotating the bracket 24 clockwise against the elastic force of the tension spring 26.

The process cartridge 22 mounted on the copying machine 10 has a photosensitive drum 11, a charging device 12, and a cleaning device 16 incorporated therein in advance.

When assembling these members, first, the photosensitive drum 11 is rotatably mounted, and then the cleaning blade 16A of the cleaning device 16 is mounted.

The cleaning blade 16A is fixed to a support piece 25 previously fixed to the bracket 24, and the bracket 24 to which the cleaning blade 16A is fixed is incorporated into the process cartridge 22 via the support shaft 23.
The lower surface of the swinging end of the bracket 24 and the process cartridge 2
A tension spring 26 is arranged between the second stationary part and the second stationary part. As a result, the cleaning blade 16 </ b> A
1 comes into contact with the peripheral surface.

A part of the peripheral surface of the photosensitive drum 11 has a process cartridge 22 formed at a position facing the developing device.
A lubricant using polyvinylidene fluoride (for convenience, a reference numeral B shown in FIG. 6 is used) is applied to the protruding range (a range indicated by reference numeral L in FIG. 3). You.

The photosensitive drum 11 is rotated once after the lubricant B is applied thereto.

At this time, the cleaning blade 16A
The bracket 24 is separated from the peripheral surface of the photosensitive drum 11 by leaning the handle 24A and rotating in a clockwise direction against the habit of the tension spring 26.

Immediately before the photosensitive drum 11 is rotated to reach the position facing the cleaning blade 16A, the cleaning blade 16A is moved by the action of the tension spring 26 when the handle 24A of the bracket 24 is released. It comes into contact with the peripheral surface and faces the leading position of the lubricant B. As a result, the lubricant B is scraped off by the cleaning blade 16A as shown in FIG. 4, and does not reach the charging device 12 located on the downstream side in the moving direction of the photosensitive drum 11.

When the scraping of the lubricant B is performed by the cleaning blade 16A, the charging device 12 is mounted on the upper portion of the process cartridge 22, and the photosensitive drum 1
1 (the state shown by a two-dot chain line in FIG. 4).

According to this embodiment, the lubricant B is not applied to the cleaning blade 16A. Therefore, the lubricant B does not drop from the cleaning blade 16A onto the photoconductor drum 11 at all, so that the lubrication to the charging device 12 located downstream of the cleaning blade 16A in the moving direction of the photoconductor drum 11 does not occur. No transfer of agent occurs. In addition, since the charging device 12 is provided as a component that can be attached to and detached from the process cartridge 22, the photosensitive drum 11 is rotated several times before the charging device 12 is mounted, and the photosensitive drum 11 is If the cleaning device 16A is repeatedly brought into contact with and separated from the lubricant application position to further improve the effect of scraping off the lubricant, and the charging device 12 is mounted, the charging device 1
2 can be completely prevented from entering the lubricant.

Next, a modification of the main part of the present invention will be described with reference to FIG.

The example shown in FIG.
6A is coated with a lubricant.

The cleaning blade 16A has the same structure as that shown in FIG.
1 are provided so as to be able to come and go.

The lubricant B is applied to the cleaning blade 16A.
Instead of being applied over the entire surface of the photosensitive drum 1
The area excluding the downstream side in the moving direction 1 (the direction of the arrow in the drawing) is selected and painted. Not surprisingly,
The cleaning blade 16A is also applied to the edge of the cleaning blade 16A which is in contact with the peripheral surface of the photosensitive drum 11.

According to such a configuration, the photosensitive drum 1
The lubricant B is not applied to the surface 16A1 of the cleaning blade 16A that is in contact with the cleaning blade 16A and faces the charging device 12 side. As a result, the lubricant does not fall on the surface of the photoconductor drum 11, so that a situation in which the lubricant B moves toward the charging device 12 as the photoconductor drum 11 moves does not occur.

When applying the lubricant to the area other than the surface 16A1, masking is applied to the area of the surface 16A, or the surface 16A is cleaned after the lubricant is applied.

The cleaning blade 16A is attached to the bracket 24 shown in FIG.
Instead of being provided so as to be able to contact and separate from the process cartridge 22, it is also possible to provide the process cartridge 22 fixedly to an immovable portion of the process cartridge 22. The application range of the lubricant B in this case is the same as that shown in FIG.

As the lubricant, a semi-milled material such as zinc stearate can be used instead of powdered polyvinylidene fluoride. Further, the photosensitive drum 11
As a means for reducing the friction coefficient at the edge portion corresponding to the contact surface of the cleaning blade 16A with respect to the peripheral surface, a fluorine resin can be coated.

[0062]

According to the first aspect of the present invention, the latent image carrying
When the process cartridge is installed in the image forming apparatus,
Low friction on part of its surface only when first installed
Cleaning lubricant
The lubricant is opposed to the cleaning
At the application position of the low friction lubricant on the latent image carrier.
Scraping of the above low friction lubricant
The contact charging device is connected to the low friction lubricant.
After the scraping of the
Because it is incorporated, for the built-in contact charging device
A state where there is no transfer of the low friction lubricant can be maintained. This
As a result, the lubricant for low friction is transferred to the contact charger and attached.
To prevent the occurrence of charging unevenness.
It is possible to reliably prevent the occurrence of defective images
Becomes

[0063]

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an example of a copying machine as an embodiment of the present invention.

FIG. 2 is a schematic diagram for explaining a configuration of a process cartridge used in the copying machine shown in FIG.

FIG. 3 is a schematic diagram for explaining one process of assembling the process cartridge shown in FIG. 2;

FIG. 4 is a schematic diagram for explaining another process of assembling the process cartridge shown in FIG. 2;

FIG. 5 is a partial cross-sectional view for explaining a partially modified example of the copying machine shown as an embodiment of the present invention.

FIG. 6 is a partial cross-sectional view illustrating a relationship between a cleaning blade and a photoconductor used in a conventional image forming apparatus.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 Copier as one of image forming apparatuses 11 Photoconductor drum 12 Charging device 16 Cleaning device 16A Cleaning blade 16A Surface of cleaning blade facing charging device 22 Process cartridge

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G03G 21/00 G03G 21/10-21/12

Claims (1)

(57) [Claims] A latent image carrier having a photoconductive layer on its surface;
A contact charging device for uniformly charging the photoconductive layer by contacting the latent image carrier; and a latent image carrier after transferring an image obtained by processing a visible image of the electrostatic latent image formed on the latent image carrier. Provided to be able to contact and separate from the latent image carrier for cleaning the body
The blade and Te assembly method smell <br/> of an image forming apparatus having a process cartridge disposed in one of the units, the latent only when the upper Symbol process cartridge is incorporated initially into the image forming apparatus the cleaning blade upon the application of the low friction lubricant in a portion of the surface of the image carrier is brought into contact with the coating position of the low-friction lubricant for the latent image carrier the low-friction lubricant scraped, low-friction
An assembling method of the image forming apparatus, wherein the contact charging device is incorporated in the process cartridge after the scraping of the lubricant for use is completed .