JP2974264B2 - Image forming device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a laser beam printer or a copying machine.

[0002]

2. Description of the Related Art FIG. 5 shows an example of an image forming apparatus as a conventional image forming apparatus with a detachable process cartridge.

The laser beam printer 1 has a main body frame 2 and a printer front plate 5 whose base is pivotally connected by a hinge shaft 3 and which can be freely opened and closed. A process cartridge 6 as an image forming unit is provided in the main body frame 2. The process cartridge 6 includes a photosensitive drum 7 rotating in the direction of the arrow, a primary charger 9 for uniformly charging the photosensitive drum 7, a developing device 10, and a cleaner 11 including a cleaning blade 11a.
The developing device 10 includes a developing sleeve 12, a developing container 10a containing a toner 13, and the like.

The photosensitive drum 7 of the process cartridge 6
Is exposed by a laser beam L passing through an opening 6b formed in an outer cover 6a of the process cartridge 6, and a latent image is formed. The laser scanner 15 for irradiating the laser beam L includes a scanner motor 16, a polygon mirror 17, a lens 19, and the like. The laser scanner 15 is an external host computer (not shown).
Laser beam L according to image information input from
To expose the photosensitive drum 7. When the process cartridge 6 is mounted in the laser beam printer 1, the mechanical drive system and the electric circuit system of the process cartridge 6 and the laser beam printer 1 are connected.

A paper feed tray 20 as a first paper feed unit is detachably mounted on the printer front plate 5, and a plurality of sheets P1 are stacked thereon. The sheet feeding roller 21 for feeding the sheet P1 and the sheet material P1
Separation pads 22 for separating sheets one by one are provided. A first sheet transport path 25 for guiding the sheet material P1 is provided between the paper feed roller 21 and a pair of registration rollers 23 provided downstream thereof.

On the other hand, a paper feed cassette 2 serving as a second paper feed unit
6 includes a middle plate 27 on which the sheet material P2 is stacked, a pressing plate 29 for urging the front portion of the middle plate 27 upward, and the like. In the figure, a clockwise rotation behavior is given. A sheet feeding roller 31 is in contact with the sheet material P1, and
The uppermost sheet material P1 is fed to the second sheet conveying path 33 by the sheet feed roller 31 rotating in the direction of the arrow while being separated by the separation claw 32.

A cassette guide 35 is provided between the paper feed roller 31 and the second sheet transport path 33 so as to be vertically movable in the paper feed cassette 26. It is urged upward by the elastic force of the compression spring 36, and its upper portion extends into the main body frame 2. The sheet cassette 26 can be moved in and out of the main body frame 2 in the X and Y directions.

The second sheet conveying path 33 and the pair of registration rollers 23 merge at a junction 40.
A sheet transport path 41 for guiding sheets from a sheet cassette (not shown) additionally provided below the sheet cassette 26 also joins the junction 40. A paper guide member 43 for switching between the first sheet conveying path 25 and the second sheet conveying path 33 and the sheet conveying path 41 is rotatably disposed at the merging section 40.

The photosensitive drum 7 is provided with a transfer roller 45 for transferring the toner image onto the sheet material P1 (P2) by pressing the sheet material P1 (P2) conveyed by the registration roller pair 23 against the photosensitive drum 7. Have been. On the downstream side of the transfer roller 45, a guide plate 47 for guiding the sheet material P1 (P2) after transfer to the fixing device 46, a paper guide member 50 fixed to a lower portion of the fixing frame 49, and the like are provided. The guide member 50 has a shape curved toward the guide plate 47 and has a length substantially equal to the width of the sheet material P1 (P2). Further, the lower end of the guide member is arranged at a minute interval with respect to the peripheral surface of the photosensitive drum 7. The fixing device 46 includes a fixing heating roller 46a.
And a pressure roller 46b for pressing the sheet material P1 (P2) against the fixing device 46.

Downstream of the fixing device 46, a fixing guide 52 provided on the printer front plate 5, a paper discharge guide 53 provided on the main body frame 2 and the like are sequentially arranged. Further, on the downstream side of the paper discharge guide 53, a paper discharge roller group 57 composed of a paper discharge roller 55 and a plurality of paper discharge rollers 56 pressed against the paper discharge roller 55 is disposed. The sheet material P1 (P2) is stacked on the sheet discharge tray 59.

The above-mentioned paper feed tray 20, paper feed roller 21,
The transfer roller 45, the guide plate 47, the fixing device 46, etc. are all mounted on the printer front plate 5 side, respectively.
If the fed sheet material P1 (P2) is jammed, the printer front plate 5 is opened as shown in FIG. 2 to remove the jammed paper.

According to a printer command input to the laser beam printer 1, the sheet feed tray 20 or the sheet feed cassette 26
Sheet material P1 (P2) is fed, and the fed sheet material P1 (P2) is skewed by the registration roller pair 23 via the junction 40 and is fed to the photosensitive drum 7 at a predetermined timing. Conveyed.

As the sheet material P1 (P2) passes between the photosensitive drum 7 and the transfer roller 45, the transfer roller 45
(Voltage having a polarity opposite to that of the toner) and the pressing force of the transfer roller 45 against the photosensitive drum 7, the toner image on the photosensitive drum 7 is sequentially transferred to the sheet material P1 (P2). The voltage application to the transfer roller 45 is performed when the leading end of the sheet material P1 (P2) reaches a contact portion (transfer portion) between the photosensitive drum 7 and the transfer roller 45.

The sheet material P1 (P2) that has passed through the transfer section
Is separated from the photosensitive drum 7 and guided by a guide plate 47 or guided by a paper guide member 50 and introduced into the fixing device 46. The sheet material P1 (P2) to which the toner image has been transferred in the fixing device 46 is discharged onto a discharge tray 59 by a discharge roller group 57.

After the transfer of the toner image, the photosensitive drum 7 is cleaned by the cleaner 11 to remove the remaining toner and other contaminants, and thereafter performs the image forming operation repeatedly. By the way, paper dust usually adheres to the sheet material,
The paper powder adheres to a portion that comes into contact when the sheet material is conveyed. The paper dust is stacked as a large number of sheet materials are conveyed. As a place where paper dust adheres,
Although there are a paper feed roller 21 and a registration roller pair 23, the width of the paper feed roller 21 in the longitudinal direction is usually short and the width of the registration roller pair 23 in the longitudinal direction is longer than that of the paper supply roller 21. The amount of paper dust adhering to 23 is very large.

Normally, the registration roller pair 23 is an important part where the image accuracy is affected by the outer diameter accuracy, the pressure of the roller pair, and the like.
The adhesion of paper dust to the paper is extremely undesirable in image formation. Therefore, in order to remove the paper dust adhering to the pair of registration rollers 23, a thin film-shaped scraper 70 (see FIG. 5) is conventionally mounted on the base 71, and the tip of the scraper 70 is moved to the registration roller pair 23 in the counter direction. It is contacted toward. In this case, since the scraper 70 generally uses a very thin film such as a polyethylene sheet material having a thickness of about 100 μm, as shown in FIG. In order to prevent adverse effects such as deformation due to contact, the process cartridge 6 is
The scraper 70 is provided substantially below the pair of registration rollers 23 so as not to come into contact with each other.

[0017]

However, in the above conventional apparatus, the scraper 70 and the base 71 are located below the registration roller pair 23. (1) The scraper 70 separates the registration roller pair 23 from the registration roller pair 23. It is very difficult to clean the paper dust that has been scraped off on the base 71 and accumulated. (2) The workability when exchanging the scraper 70 and the base 71 for the purpose of maintenance of the apparatus is extremely poor.

There was a problem that:

Accordingly, the present invention provides an image forming apparatus in which a process cartridge can be attached to and detached from an apparatus main body without contacting a film for cleaning a registration roller, and maintenance of a film and a base unit is facilitated. The purpose is to do so.

[0020]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and a process cartridge having a photosensitive member and process means contributing to image formation on the photosensitive member is attached to and detached from a main body device. In an image forming apparatus provided so as to be capable of being provided, a registration roller provided in the apparatus main body, a film for abutting one side of the registration roller to clean the registration roller, and a base of the film are fixed. A base, and a guide unit that guides the process cartridge so that the process cartridge does not contact the film when the process cartridge is attached to or detached from the apparatus main body, and a guide unit provided integrally with the base. It is characterized by having.

[0021]

According to the above construction, the paper dust adhering to the pair of registration rollers is removed by the film, cleaned, and stacked on the base. When the process cartridge is attached to and detached from the main body frame, the process cartridge is guided by the guide portion of the base to prevent the process cartridge from contacting the film. This makes it possible to arrange the film in a substantially horizontal direction of the pair of registration rollers, thereby facilitating the maintenance of the film and the base unit and easily removing the paper dust removed from the pair of registration rollers. It is possible to do.

[0022]

[0023]

An embodiment of the present invention will be described below with reference to the drawings. Elements having the same meanings as those shown in FIGS. 5 and 6 are denoted by the same reference numerals, and description thereof is omitted.

In FIGS. 1 and 2, a base 81 is disposed substantially in the horizontal direction of the registration roller pair 23. A base of a film (hereinafter, referred to as a scraper) 80 is fixed to the base 81, and a free end of the scraper 80 is
It is in contact with the peripheral surface of the pair of registration rollers 23 in the counter direction. The paper dust adhering to the peripheral surface of the pair of registration rollers 23 is
The data is written down by the scraper 80 and is stacked on the base 81.

On both sides of the base 81, guide portions 81a and 81b (the reference numeral 81b is not shown) are provided integrally with their free ends facing upward. In addition, the guide part 81a,
81b can be formed separately and fixed to the base 81. The guide portions 81a and 81b are configured to be located above the scraper 80 so that the process cartridge 6 does not come into contact with the scraper 80 when the scraper 80 is attached or detached.

As shown in FIG. 4, guide legs 61a and 61b are provided on the outer cover 6a of the process cartridge 6. When the process cartridge 6 is mounted in the main body frame 2, the driven gear 145 in the process cartridge 6 can mesh with the drive gear 144 in the main body frame 2.

When the process cartridge 6 is attached to and detached from the main body frame 2, the legs 61 a and 61 b of the process cartridge 6 are connected to the guides 81 a and 81 b of the base 81.
And the process cartridge 6 is prevented from contacting the scraper 80. This prevents the scraper 80 from being damaged due to the attachment / detachment of the process cartridge 6. Further, the scraper 80 does not need to be disposed below the registration roller pair 23 unlike the conventional apparatus,
Since the registration roller pair 23 can be disposed substantially in the horizontal direction, the paper dust loaded on the base 81 can be easily taken out.

[0028]

As described above, according to the present invention,
A guide section for guiding the process cartridge is provided on the base supporting the film for removing the paper dust attached to the registration roller, so that the contact between the process cartridge and the film occurs when the process cartridge is attached to or detached from the main unit. Is prevented, and the film can be disposed substantially in the horizontal direction of the registration roller. Thus, (1) the paper dust scraped off by the film and accumulated on the base can be easily taken out.
(2) The life of the film can be extended and the film can be easily maintained.

[Brief description of the drawings]

FIG. 1 is a vertical sectional side view of an image forming apparatus to which an embodiment of the present invention is applied.

FIG. 2 is a longitudinal sectional side view of the image forming apparatus with the printer front plate opened.

FIG. 3 is a perspective view of a process cartridge.

FIG. 4 is a perspective view of a base portion of the image forming apparatus.

FIG. 5 is a vertical sectional side view showing an example of a conventional image forming apparatus.

FIG. 6 is a perspective view of the image forming apparatus with the printer front plate opened.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Image forming apparatus (laser beam printer) 2 Main body frame 5 Printer front plate 6 Process cartridge 7 Photoconductor (photosensitive drum) 23 Registration roller pair 61a Leg 80 Film (scraper) 81 Base 81a, 81b Guide

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Akira Hishita 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Inventor Akito Nagayama 6-3-3 Shimorenjaku, Mitaka-shi, Tokyo (56) References JP-A-2-148080 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G03G 21/10-21/12 G03G 15/00 550 G03G 21 / 16-21/18

Claims (1)

(57) [Claims] In an image forming apparatus, a process cartridge having a photoreceptor and a process unit contributing to image formation on the photoreceptor is detachably provided in a main body device. Laura and
A film for abutting the resist roller on one side to clean the resist roller, a base on which a base of the film is fixed, and a contact of the process cartridge with the film when the process cartridge is attached to or detached from an apparatus main body. An image forming apparatus which guides the process cartridge so as not to be guided, and has a guide unit provided integrally with the base.