JPH01195486A - Cleaning device - Google Patents

Abstract

PURPOSE:To decrease the damage of a brade ridge line and to reduce an impact noise by forming a cam area, which operates a brade in a pressure-contact direction, in a step shape and preventing a cam from being turned by force due to a cam follower. CONSTITUTION:The cleaning brade 47 of a cleaning device is fixed through a fitting frame 47' to a rotary shaft 471. When the brade 47 transits from the condition of a cancel from a sensitive body drum 40 to an area (a) in the step shape, a cam follower 473 is moved just like going down the step one by one and further, the moving is not operated as the force, which revolves the cam 474, on the surface of respective stages. Accordingly, the brade 47 approaches the sensitive body drum 40 by stages and finally, the brade 47 is slided to the sensitive body drum 40. Then, it can be avoided that the brade 47 is rapidely pressurized contact with the sensitive body drum 40. Thus, impact for the brade to hit the drum is made weak and the damage of the brake ridgeline can be decreased. Then, the impact noise can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a cleaning device used in an electrophotographic image forming apparatus.

[Conventional technology]

Recently, an image forming apparatus that can form a hard copy of a color image using an electrophotographic method has appeared. For example, the surface of the photoreceptor drum is charged with a charger at one rotation opening, a latent image corresponding to a first color (for example, red) is formed, and the latent image is developed with a developer containing red toner. It is charged again in the third rotation to form a latent image corresponding to a second color (for example, blue), and is superimposed and developed using a developer containing blue toner. The latent image is charged again in the third rotation to form a latent image corresponding to a third color (for example, black) and developed in a developing device containing black toner, and then transferred to transfer paper at the same time. There are some that allow color hard copies to be obtained.

In the case of the above color image forming apparatus, since the color toner is layered on the surface of the photoreceptor drum, the cleaning blade is in a non-contact position with the photoreceptor drum before it is transferred to the transfer paper, and all three colors are developed. After being transferred to transfer paper, it is pressed onto a drum. However, when the third color is formed in the third rotation of the photoreceptor drum, transfer to the transfer paper starts sequentially from the formed part, so the cleaning blade is pressed against the drum surface during the third rotation. That will happen. In addition, since the blade that is pressed against the drum from the middle of the third rotation continues to the first rotation of the next image forming cycle, the blade is pressed against the drum at the beginning of the -th rotation, and is released from the middle of the rotation. Ru. That is, the blade is crimped partway through the first rotation of the photosensitive drum, is not crimped during the second rotation, and is crimped halfway during the third rotation. The operation of such a blade has conventionally been carried out using a shaft 70 as shown in FIG.
The reciprocating movement of the cam follower 72 (in the range indicated by the two-dot chain line) is used to make sliding contact with the cam 71 that rotates.

[Problem that the invention seeks to solve]

However, the conventional cam 71 has a shape as shown in the figure, and a cam follower 72 that follows the rotation of the cam and reciprocates as shown by a two-dot chain line around a fulcrum 73 covers an area a from the maximum diameter to the minimum diameter of the cam. When the cam is moved, that is, when the blade (not shown) is rotated in a direction in which the blade (not shown) is pressed against the photosensitive drum (not shown), the cuff 4 in the direction of the arrow is applied to the cam.

If a spring clutch is used as the drive transmission mechanism for the cam 71, the direction of this force is the direction in which the spring loosens, so this force turns the cam 71 and instantly presses the blade against the photoreceptor drum. There was a problem that

In other words, not only is the blade ridgeline damaged and a loud impact sound caused by forcefully pressing the blade onto the photoreceptor drum, but also the resist performance for overlapping images deteriorates due to large load fluctuations occurring on the photoreceptor drum. There was a problem that it caused deterioration.

This invention is intended to solve the above-mentioned problems, and aims to provide a cleaning device in which the impact of the blade hitting the drum is weakened as much as possible, thereby reducing damage to the blade ridgeline and reducing impact noise.

[Means for solving problems]

To achieve the above object, the present invention provides a cleaning device that presses and releases a blade from a photoreceptor drum in conjunction with a cam follower that reciprocates using a cam, in which a cam area for operating the blade in the pressing direction is formed in a step-like manner. The cam is configured so that the cam is not rotated by the force of the cam follower located in the cam region that operates the blade in the crimping direction.

〔Example〕

Next, the present invention will be described based on an embodiment shown in the accompanying drawings.

In FIG. 1, A is a document reading section, and B is a part of the printer. The document reading section A illuminates a document 2 placed on a platen glass 1 provided on the top surface of the housing with a fluorescent lamp 5 provided on a carriage 4 moving on a slide rail 3, and passes the reflected light through a slit 6. The lens can be taken out by the first mirror 7 through the mirror unit 8, and led out to the lens reading unit 20 via mirrors 9 and 9' provided in the movable mirror unit 8.

The carriage 3 and the movable mirror unit 8 are connected to a pulley 12. which is connected to a stepping motor 10 via a wire 11. 13. 15a and 15b. In this case, the movable mirror unit 8 moves on the slide rail 3 at 1/2 the speed of the carriage 4 in the same direction. Reference numerals 16 and 17 denote standard white plates provided on the bottom surface of both ends of the platen glass 10.
Reference numeral 17 is for obtaining a standard white signal before the start and after the end of the document reading scan.

The lens reading unit 20 is configured as shown in the second figure (lens 2
1. Prism 22, first reading board 24, red channel (hereinafter referred to as R-ch) CCD 25, second reading board 2
6. Cyan channel (hereinafter referred to as C-ch) CCD2
It consists of 7. The original light image transmitted by the first mirror 7 and (1) mirrors 9 and 9' is focused by the lens 21, and converted into an R-ch image and a C-ch image by the guichroic mirror 23 built into the prism 22. R-ch CCD 25 separated into two and provided on the first reading board 24,
An image is formed on each light receiving surface of the C-chccD 27 provided on the second reading board 26. This R-chCCD2
The image signals output from the C-ch CCD 27 and the C-ch CCD 27 are processed in a signal processing section 28, and color-separated color signals corresponding to the toner colors are output to a writing unit 29 provided in the printer B.

As shown in the third diagram, the writing unit 29 includes a semiconductor laser 31, a polygon mirror 32 that is rotated by a drive motor 30 to rotate and scan the laser beam generated by the semiconductor laser 31, an fθ lens 33, and cylindrical lenses 35 and 36. We are prepared. The laser beam generated by the semiconductor laser 31 passes through the cylindrical lens 35, is rotated and scanned by the polygon mirror 32, and passes through the θ lens 33, the cylindrical lens 36, and the reflecting mirror 37, and the surface of the photoreceptor drum 40 is uniformly charged. is projected to form an electrostatic latent image 39. Reference numeral 34 is an inte-nox sensor that detects the start of beam scanning, and detects the start of scanning by the laser beam via a reflecting mirror 38.

When the index sensor 34 detects the start of scanning, the first color signal output from the signal processing section 28 is input to the writing unit 29, and modulation of the beam by the color signal is started. The modulated beam is applied to the photosensitive drum 4 which is uniformly charged in advance by a charger 41.
Scan over 0. Main scanning by this beam and the drum 40
A latent image corresponding to the first color is formed on the drum surface by the sub-scanning caused by the rotation of the drum, and the latent image is developed by a developing device 43 loaded with, for example, red toner. After this red toner image is formed, the drum surface is charged again by the charger 41 in the next copy cycle. In this case, the cleaning blade 47 of the cleaning device 46 is separated from the photosensitive drum 40 to prevent the red toner image from being scraped off.

Next, the second color signal output from the signal processing section 28 is input to the writing unit 29, and the second color signal is input to the writing unit 29.
Similarly to the above, a latent image corresponding to the second color is formed on the surface. The latent image is then developed by a developing device 44 loaded with, for example, blue toner. That is, the blue toner image is formed on top of the already formed red toner image.

Next, based on the control signal generated by the signal processing section 28, a black toner image is formed on the surface of the photosensitive drum 40 by the developing device 45 loaded with black toner by the same operation as described above.

Cleaning blade 47 of the cleaning device 46
is fixed to a rotating shaft 471 via a mounting frame 47' as shown in the fourth figure. A cam follower 473 is pivotally supported at the tip of a swinging lever 472 whose base end is fixed to the rotation shaft 471 . The cam follower 473 is in sliding contact with the cam 474 by the tension of a spring 475. The cam 474 is fixed to a shaft 476 that is connected via a spring clutch (not shown) to a suitable drive source, for example, a drive source that drives the developing sleeve of the developing device 44, and is moved in accordance with the copy cycle of the photoreceptor drum 40. The rotation is controlled at the correct timing. This cam 474 has the shape shown in FIG. 5, and the cam follower 4 moves back and forth around the rotating shaft 471 following the rotation of the cam 474.
When the cam 73 moves in area a from the maximum diameter to the minimum diameter of the cam, the blade 47 is rotated in the direction of pressing the photosensitive drum 40, and conversely, when the cam has already moved from the minimum diameter to the maximum diameter in the area a, the blade 47 47 is rotated in a direction to release it from the photoreceptor drum 40. Further, a cam region a in which the cam 474 rotates in a direction to press the blade 47 is formed in a stepped shape. The outer surface 477 of each stage is a concentric arc. That is, all the force 478 applied to the cam 474 of the cam follower 473 that is in sliding contact with each stage is applied to the cam 47.
It is designed to concentrate on the axis of axis 476 of No. 4.

Therefore, the transition from the state where the cam follower 473 is at the maximum diameter of the cam 474 and the blade 47 is released from the photoreceptor drum 40 as shown in FIG. 6(al) to the stepped region a as shown in FIG. In this case, the cam follower 473 moves down the stairs one step at a time, and since no force acts to rotate the cam 474 on each step, the blade 47 approaches the photoreceptor drum 40 step by step. Finally, the blade 47 is brought into sliding contact with the photoreceptor drum 40 as shown in FIG.

As described above (the developed three-color toner images are separated one by one by the paper feed heald 52 of the paper feed unit 5o in the transfer unit 51, and are separated one by one by the paper feed roller 53 and placed on the guide plate 50.
The images are transferred all at once onto the recording paper 55 that has been sent through the process.

After that, the recording paper is transferred to the photosensitive drum 4 by the separation electrode 56.
The fixing device 5 is separated from the
8, and is fixed by heat and pressure with fixing rollers 58a and 58b, and then transferred to output roller 5 as a color hard copy.
It is held between 9a and 59b and discharged outside the machine.

After the transfer is completed, unnecessary toner remaining on the photosensitive drum 4o is scraped off by contacting the blade 47 of the cleaning device 46. A cleaning roller 48 provided on the downstream side of the cleaning device 46 completely removes the small amount of toner left behind between the drum surface and the blade when the blade 47 separates from the drum 4o for the next exposure and development after cleaning. It is used for removal and rotates in the opposite direction to the drum.

〔Effect of the invention〕

As described above, the present invention is a cleaning device that presses and releases a blade from a photoreceptor drum in conjunction with a cam follower reciprocally moved by a cam, characterized in that the cam area for operating the blade in the pressing direction is formed in a step-like manner. This prevents the cam from being actively rotated by the force of the cam follower located in the cam region that operates the blade in the crimp direction. Therefore, the impact of the blade hitting the drum is weakened, damage to the blade ridgeline can be reduced, and impact noise can be reduced. Moreover, since the impact when the blade hits the photoreceptor drum is small, the resist performance for overlapping images is not deteriorated, and various other excellent effects are achieved.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, in which Fig. 1 is a hydrophilic sectional view of the copying machine of the present application, Fig. 2 is an enlarged view of the lens reading unit, Fig. 3 is a plan view of the writing unit, and Fig. 4. is a perspective view showing the relationship between the photosensitive drum, the blade, the cam, and the cam follower, FIG. 5 is an explanatory diagram of the cam of the present application, and FIG. 6 Ta
) to (C) are explanatory diagrams showing the action of the cam, and FIG. 7 is an explanatory diagram of a conventional cam. A--Document reading section B-Printer part 40--Photoconductor drum 41-Charger 43 to 45--Developer 46-Cleaning device 47-Blade 471-Rotating shaft 472-Swinging lever 473-Cam follower 474--Cam 475--Spring 476-11 Axis 477--Each side of the stairs Fig. 2, 52 5υ Fig. 4 47 Otsu 4r74

Claims (2)

[Claims] (1) A cleaning device that presses and releases a blade from a photoreceptor drum in conjunction with a cam follower that reciprocates using a cam, characterized in that a cam region that operates the blade in a pressing direction is formed in a step-like manner. . (2) The cleaning device according to claim 1, wherein each stepped surface of the cam region is a concentric arc.