JPH0540372A - Image formation unit - Google Patents

Abstract

PURPOSE:To hold the quantity of intrusion of the fur brush of a cleaning device into a photosensitive drum. CONSTITUTION:Abutting rolls 26 and 26 are fitted to both ends of the shaft 25 of the fur brush roller 24 of the cleaning device 10 rotatably and movably in a thrust direction. A ring 50 equipped with a pin 50a is fitted rotatably to the boss peripheral surface of each of the abutting roll 26. The pin 50a is slidably intruded into the groove 29a of a cylindrical cam 29 fixed on a rotary shaft 34. Further, cleaning rolls 28 are provided fixedly to the front and rear end parts of the rotary shaft 34. Then the cylindrical cam 29 on the rotary shaft 34 is rotated through a gear 30 engaging the gear 32 of the shaft 25 and the abutting rolls 26 are swung in the thrust direction through the pin 50a engaging the groove in the peripheral surface to expand the abutting range on the photosensitive drum 14.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming unit such as a cleaning device or a developing device of an image forming device such as a copying machine, a facsimile, a printer, etc.
In order to maintain a constant distance between the shaft of the rotating roller member and the surface of the latent image carrier, a roller is provided on the shaft portion of the rotating roller member,
The present invention relates to improvement of a mechanism for maintaining a constant distance between the shaft of the rotary roller member and the surface of the latent image carrier in the image forming unit that brings the roller into contact with the surface of the latent image carrier.

[0002]

2. Description of the Related Art Conventionally, as a cleaning device which is an image forming unit of this type, a fur brush is used as a cleaning member, and a cleaning roller having the fur brush planted on the peripheral surface is used. It is known to remove residual toner by rotatably driving in a predetermined direction and rubbing the latent image carrying surface in a state of facing the surface so as to bite a predetermined amount. There is also known a cleaning device in which a magnetic cleaning carrier is carried on a sleeve containing a magnet to form a magnetic brush and the magnetic brush is used as a cleaning member. Further, in a developing device which is an image forming unit of this type, a developing roller is opposed to the surface of the latent image carrier with a predetermined gap, and the developer carried on the peripheral surface of the developing roller is transferred to the latent image carrier surface. The latent image is developed by feeding it to the image. In any case, maintaining a constant distance between the cleaning roller and the latent image carrier is important for maintaining a constant cleaning property.

Therefore, an abutting roller having a predetermined outer diameter is attached to the shaft of a cleaning roller or the like, and the peripheral surface of the roller is brought into contact with the surface of the latent image carrier to keep the distance therebetween constant. Has been.

[0004]

However, in the conventional distance control configuration using the abutting rollers, the same position on the surface of the latent image bearing member (for example, in the case of a drum-shaped latent image bearing member, the drum shaft is used). Since the structure is such that the abutting roller abuts on the same position in the same direction), the surface of the latent image carrier on which the abutting roller abuts wears and deteriorates, and the distance between the cleaning roller and the latent image carrier changes. There was a problem that it would end up. Particularly, in the case of using an organic photoconductor (OPC) as the latent image carrier, since the photosensitive layer is relatively soft, the surface is easily peeled off, and the distance is easily changed. Further, in the case of other devices such as a developing device which are arranged at a predetermined distance from the latent image carrier, when the distance control using the similar abutting rollers is performed, the surface of the latent image carrier is Due to wear, the distance from the latent image carrier in the other device has also changed. Further, when the scattered toner in the device enters the contact portion between the abutting roller and the surface of the latent image carrier, the entering toner gradually adheres to the abutting roller peripheral surface or the latent image carrier peripheral surface in a large amount. The above distance had changed. In order to prevent this, a scraper made of mylar or the like that comes into contact with the latent image carrier surface is provided on the upstream side in the moving direction of the latent image carrier surface with respect to the contact portion between the abutting roller and the latent image carrier surface. Although the surface of the latent image bearing member is also cleaned, the scraper has a life due to wear and has poor replaceability, and it is difficult to maintain the performance over time.

The present invention has been made in view of the above problems, and an object of the present invention is to maintain the distance between the shaft of the rotary roller member and the surface of the latent image carrier constant. In the image forming unit in which the shaft is provided with a roller and the roller is brought into contact with the surface of the latent image carrier, abrasion of the surface of the latent image carrier is suppressed, and the shaft of the rotary roller member and the latent image are held for a relatively long period of time. An object is to provide an image forming unit capable of maintaining a constant distance from the surface of a carrier.

[0006]

In order to achieve the above object, the present invention provides a shaft portion of a rotary roller member for maintaining a constant distance between the shaft of the rotary roller member and the surface of the latent image carrier. In the image forming unit in which a roller is provided on the surface of the latent image carrier, the roller is attached so as to be movable in the thrust direction of the shaft portion, and the roller is rocked in the thrust direction. It is characterized in that a moving mechanism and a cleaning member for cleaning the peripheral surface of the roller are provided.

[0007]

In the image forming unit of the present invention, the roller provided on the shaft portion of the rotary roller member by the swing mechanism and abutting against the latent image carrying surface is swung in the thrust direction on the shaft portion. , The contact position of the roller on the surface of the latent image carrier is dispersed, and the cleaning member cleans the peripheral surface of the roller.

[0008]

EXAMPLE An example in which the present invention is applied to a cleaning device in a color electrophotographic printer will be described.
First, an outline of the entire printer will be described with reference to FIG. 3 showing an overall schematic configuration. The surface of a drum-shaped photoconductor (hereinafter referred to as a photoconductor drum) 14, which is a latent image carrier that is rotated counterclockwise, is charged by a charger 11 and then black (BL) by an optical writing device 12. Scanning exposure of the image signal of (1) to form a negative latent image (a state in which the image area is exposed and the surface potential of the photoconductor is attenuated). The latent image is developed by the black developing device BL (using black toner) of the developing device 13 to form a black toner image on the photoconductor drum 14. At this time, the developing devices Y, M, and C (each of which uses yellow, magenta, and cyan toners) other than the black developing device BL in the developing device 13 are controlled so that the toner does not fly. And static elimination
Charge the photoconductor drum 14 with the PCC charger 9,
The black (BL) latent image on the photosensitive drum 14 is discharged. At this time, the cleaning device 10 is separated from the photoconductor drum 14 and is in an inoperative state. Then, by the same method as the method of forming the black (BL) toner image, the processes of charging, exposing, developing and discharging are repeated, and Y,
Toner images of M and C (yellow, magenta, and cyan) are sequentially superposed and formed. After all toner development is completed, the transfer charger 5 electrostatically transfers the toner image onto the transfer paper 2 conveyed by the paper feed roller 3 and the registration roller 4. The toner image transferred onto the transfer paper 2 is fixed by heating the fixing roller 6, and then discharged onto the paper discharge tray 8 by the paper discharge roller 7. On the other hand, after the electrostatic transfer, the toner image remaining on the photoconductor drum 14 is removed by the cleaning device 10 that is in pressure contact with the photoconductor drum 14 and is in an operating state, and one cycle of color image formation is completed. After cleaning the residual toner image, the cleaning device 10 is separated from the photoconductor drum 14 and put into an inoperative state.

Next, the cleaning device 10 will be described in detail with reference to FIGS. 1 (a) and 1 (b). FIG. 1A is a front view showing a schematic configuration inside a casing 20 of the cleaning device 10, and FIG. 1B is a side view showing a schematic configuration before and after the casing 20 of the cleaning device 10. Figure 1
In (a), the casing 2 of the cleaning device 10
In FIG. 0, a fur brush roller 24 for rubbing the peripheral surface of the photosensitive drum 14 for cleaning, a bias roller 21 for biting into the brush portion of the fur brush roller 24 to remove toner, and a bias roller 21 scraper 19 for scraping off the toner from the peripheral surface, and coil spring 22 for discharging the toner scraped off from the bias roller 21 by the scraper to the outside of the casing 20.
Is provided. A seal member 30 for preventing toner scattering is provided at both lower end edges of the casing 20, and a support shaft 2 for rocking the casing, which will be described later, is provided.
2 and the abutment roller 26 (see FIG. 1B), a rotary shaft 24 for rocking is provided penetrating the inside of the casing 20. Here, the fur brush roller 24 is formed by implanting conductive fibers (for example, product name "SA-7" manufactured by Toray Co., Ltd.) on the peripheral surface of a stainless steel or aluminum roller 24a.
The biting amount of the bias roller 21 with respect to the brush portion of the brush roller 24 is set to about 1 to 2 mm. The fur brush roller 24 and the bias roller 21 are rotationally driven in the same direction.

At the upper part of the casing 20 of the cleaning device 10, the fur brush roller 24 bites into the peripheral surface of the photosensitive drum 14 by a predetermined amount, and the fur brush roller 24 is separated from the peripheral surface of the photosensitive drum 14. A swinging mechanism for swinging the entire casing around the support shaft 23 is provided so that the inoperative position can be obtained. The swing mechanism includes a casing 20 and the support shaft 23.
A tension spring 51 that gives a turning force in a clockwise direction, an eccentric roller 16 attached to the drive shaft 17,
The free end portion is in pressure contact with the peripheral surface of the eccentric roller 16, and the base end portion is composed of a leaf spring 18 fixed to the upper surface of the casing 20. Explaining the swinging of the casing 20, first, during a period in which a color image is formed on the photosensitive drum 14 in a superposed manner, the fur brush roller 24 is in an inoperative position separated from the peripheral surface of the photosensitive drum 14. As described above, the rotational position of the eccentric roller 16 is set to a position where the displacement amount is minimized. Then, after the toner on the photoconductor drum 14 is transferred onto the transfer paper 2, the eccentric roller 16 is rotated about the rotation shaft 17 by 18
Rotate 0 °. Then, the casing 20 rotates counterclockwise in the drawing about the rotary shaft 23 against the force of the tension spring 51, and the fur brush roller 24 bites into the photosensitive drum 14 by a predetermined amount as shown in FIG. It comes into contact with and rubs its peripheral surface. The amount of this bite is abutting rollers 2 for maintaining the gap, which are attached to both end shafts of the fur brush roller 24 and contact the photosensitive drum 14.
It is determined by the outer diameter of 6 and the like, and is preferably 0.5 to 2 mm. The leaf spring 18 serves to attach the abutting roller 26 to the photosensitive drum 14. Eccentric roller 1 after cleaning
6 further rotates 180 °, the casing 20 rotates clockwise around the rotation shaft 23 by the force of the tension spring 51, and the fur brush roller 24 separates from the photosensitive drum 14.

Next, the schematic structure of the casing 20 of the cleaning device 10 before and after the casing 20 will be described with reference to FIG. In FIG. 1B, the abutting roller 26 is in contact with the photoconductor drum 14 and is rubbing against the photoconductor drum 14 with a biting amount. A shaft (hereinafter referred to as a brush shaft) 25 of the fur brush roller 24 is rotatably supported by front and rear side plates of the casing and further extends to the outside of the side plates. Of these, a gear 32 is fixed to a brush shaft 25 outside the front side plate 31a (front side of the machine). The gear 32 receives a rotational force from a drive gear (not shown), and the fur brush roller 24 rotates. Abutting rollers 26 are attached to the outside of the front and rear side plates of the brush shaft 25 so as to be rotatable and movable in the thrust direction. Each of the abutting rollers 26 has a diameter smaller than that of the fur brush roller 24, and has the same diameter as the fur brush roller 2 as described above.
The amount of bite into 6 is determined. And the butting roller 26
A boss is formed in the center of the machine, and a ring 50 is rotatably fitted in a groove formed in the peripheral surface of the tip of the boss. A pin 50a is provided on a part of the ring 50.
The pin 50a is supported by a locking member (not shown) so as to always face upward, and always faces upward even if the abutting roller 26 rotates. Then, the pin 50a slidably enters the groove 29a of the cylindrical cam 29 fixed on the rotary shaft 34. The groove 29a of the cylindrical cam 29 is formed in the front and rear cylindrical cams 29, 29.
Thus, they are formed symmetrically as shown in FIG. A driven gear 30 meshing with the gear 33 is provided between the front side plate 30a of the rotary shaft 34 and the front side cylindrical cam 29.
Is fixed. Further, a cleaning roller 28, which is a member for cleaning the peripheral surface of the abutting roller 26, is fixed to the outside of the cylindrical cam 29 at the front and rear ends of the rotary shaft 34. The surface layer of the cleaning roller 28 is made of felt, sponge or the like, and the overall shape is preferably a drum shape with a bulged center, but it may be a cylindrical shape. The ring 27, which is detachably attached to the outer side of the rotary shaft 34, is detachable so that the ring 27 can be replaced with one touch.

With the above structure, the drive brush (not shown) is rotated, and the fur brush roller 24 is rotated via the gear 32 on the brush shaft 25 and the brush shaft 25. At this time, the rotary shaft 34 passes through the driven gear 30 meshing with the gear 32.
Is rotated and is fixed to both cylindrical cams 29, 29.
Rotates. As a result, the groove 29a on the circumferential surface of the cylindrical cam 29 is formed.
The abutting roller 26 is oscillated symmetrically in the thrust direction via the pin 29a contained therein. At this time, the toner on the surface of the photoconductor drum 14 is pushed in the thrust direction by the end surface of the abutting roller 26, and the toner and dust are removed from the surface portion of the photoconductor drum 14 with which the peripheral surface of the abutting roller 26 abuts for cleaning. It should be noted that FIG. 1B shows a state in which the abutting roller 26 is closest to the side plate side of the cleaning unit. When the abutting roller 26 is the farthest from the cleaning device side plate 31 and comes outside, the abutting roller 2
6 and the cleaning roller 28 are not in contact with each other, and when coming inward, the peripheral surface of the abutting roller 26 is rubbed against the peripheral surface of the cleaning roller 28 to remove toner and dust on the abutting roller 26. ..
In this way, the cleaning roller 28 is not always rubbed against the peripheral surface of the abutting roller 26, but is rubbed intermittently. This is to reduce wear and fatigue of the cleaning roller 28 to extend the life of the cleaning roller 28 and improve the cleaning property.

Incidentally, the cleaning of the abutting roller 26 abutting portion on the surface of the photosensitive drum 14 is carried out by contacting a scraper on the upstream side in the moving direction of the photosensitive drum 14 than the abutting roller 26 abutting portion as in the conventional case. It is also good, Figure 2 (a) or (c)
As shown in FIG. 5, by forming a groove on the peripheral surface of the abutting roller 26, toner and dust are introduced into the groove, and the toner is caught in the pressure contact portion between the peripheral surface of the abutting roller 26 and the surface of the photosensitive drum 14. You may not be tired. 2A and 2B are a perspective view and a cross-sectional view showing an example in which a groove is formed on the peripheral surface of the abutting roller 26 in a direction perpendicular to the brush shaft 25,
(C) is a perspective view showing an example in which a groove is formed on the same circumferential surface at an angle of 30 to 60 ° with the brush shaft 25.

If the peripheral surface of the abutting roller 26 is made of a material to which toner adheres more easily than the material of the abutting roller 26 abutting portion on the surface of the photosensitive drum, the photosensitive drum 14
The toner attached to the corresponding contact part of
Of the abutting roller 2 by removing it with a cleaning roller 28 from the peripheral surface of the abutting roller 26.
By removing not only the peripheral surface of No. 6 but also the toner adhering to the corresponding contact portion of the photoconductor drum 14, the distance between the cleaning fur brush 24 and the photoconductor drum 14 can be more favorably maintained.

[0015]

According to the present invention, the roller provided on the shaft portion of the rotary roller member by the rocking mechanism and abutting against the latent image carrying surface is rocked in the thrust direction on the shaft portion. Since the contact positions of the rollers on the surface of the latent image carrier are dispersed, the abrasion of the surface of the latent image carrier can be reduced as compared with the conventional case. Also, since the cleaning member cleans the peripheral surface of the roller,
It is possible to prevent the toner from sticking to the peripheral surface of the roller. This allows
There is an excellent effect that the distance between the axis of the rotary roller member and the surface of the latent image carrier can be kept constant for a longer period of time than in the conventional case. Furthermore, if a groove for taking in the toner on the surface of the latent image bearing member is formed on the peripheral surface of the roller, the toner is taken into the groove from the portion of the surface of the latent image bearing member where the roller comes into contact with and makes a corresponding contact. Since the toner is not caught in the portion, it is possible to prevent the distance between the shaft of the rotary roller member and the surface of the latent image carrier from changing. Furthermore, in a cleaning device which is an image forming unit, as the roller rotating member, a fur brush roller having a large number of fur brushes planted on the peripheral surface of a core roller is used, and as the roller,
If an outer diameter smaller than the outer diameter of the core roller is used,
The bite amount of the fur brush portion with respect to the surface of the latent image carrier can be kept constant for a longer period of time than in the conventional case.

[Brief description of drawings]

FIG. 1A is a front view showing a schematic configuration mainly inside a casing of a cleaning device according to an embodiment, and FIG. 1B is a right side view showing a schematic configuration mainly outside the casing of the cleaning device.

FIG. 2A is a perspective view of an abutting roller according to a modified example of the cleaning device, FIG. 2B is a front view of the abutting roller, and FIG. 2C is an oblique view of another modified example of the cleaning device. FIG.

FIG. 3 is a front view showing a schematic configuration of a color electrophotographic printer using the cleaning device.

[Explanation of symbols]

1 Paper feeding cassette, 2 Transfer paper 3 Paper feeding roller, 4 Registration roller 5 Transfer charger, 6 Fixing roller 7 Paper discharging roller, 8 Paper discharging tray 9 Electrification / PCC charger, 10 Cleaning device 11 Charging charger, 12 Optical writing device 13 developing device (4 colors), 14 photoconductor drum 15 outer cover, 16 eccentric roller 17, rotary shaft, 18 leaf spring 19 scraper, 20 casing 21 bias roller, 22 recovery coil 23 rotary shaft, 24 far brush roller 25 brush shaft, 26 Abutting Roller 27 Ring, 28 Cleaning Roller 29 Cylindrical Cam, 29a Groove 30 Gear, 31 Side Plate 32 Gear, 33 Seal 34 Shaft, 50 Ring 50a Pin

Claims (4)

[Claims] 1. A roller is provided on a shaft portion of the rotating roller member in order to maintain a constant distance between the shaft of the rotating roller member and the surface of the latent image bearing member, and the roller is brought into contact with the surface of the latent image bearing member. In the image forming unit, a swing mechanism for movably mounting the roller in the thrust direction of the shaft portion and swinging the roller in the thrust direction,
An image forming unit, comprising: a cleaning member for cleaning the peripheral surface of the roller. 2. A groove for taking in the toner on the surface of the latent image carrier is formed on the peripheral surface of the roller.
Image forming unit. 3. The image forming unit according to claim 1, wherein the cleaning member is formed in a drum shape having a bulged central portion in the thrust direction. 4. A fur brush roller in which a large number of fur brushes are planted on the peripheral surface of a core roller is used as the roller rotating member, and the roller has an outer diameter smaller than the outer diameter of the core roller. The cleaning device, which is the image forming unit according to claim 1, wherein: