JPH0572949A - Cleaning device for image forming device - Google Patents

Abstract

PURPOSE:To prevent the occurrence of chatter vibration and blade stripping, etc., caused by the shortage of lubricating toner by providing a means for guiding air flow which is generated in a cleaning device due to the traveling of an image carrier and containing suspended toner toward both end parts of a cleaning blade. CONSTITUTION:Since the image carrier 1 is made to travel in a direction shown by an arrow A in order to form an image and to transfer it, the air flow shown by a figure B is generated near the rear side of the cleaning blade 3 in the cleaning device 2. Meanwhile, most of the toner recovered in the cleaning device 2 by the cleaning blade 3 drops toward a scooping sheet 15 by gravity, but the considerable quantity of the toner gradually drops down by gravity after suspending in the device 2, because of the generation of the air flow is lying. Then, an air flow guiding member 17 is provided so that a small space may be formed between the cleaning blade 3 and the member 17, and a recessed part 17a whose central part is recessed is formed, which can be realized by viewing from the image carrier 1 side. Thus, the lubricating toner can be also supplied to non-image areas on both end parts.

Description

Detailed Description of the Invention

[0001]

[Object of the Invention]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus utilizing an electrostatic transfer process, such as an electrostatic copying machine and a printer.
In particular, it relates to the cleaning device.

[0002]

2. Description of the Related Art In a known image forming apparatus that repeats the process of transferring a toner image formed on the surface of a running image carrier to a transfer material such as paper, it does not transfer to the transfer material during transfer. It is necessary to sufficiently remove the residual toner remaining on the image carrier each time. As the residual toner removing means, the cleaning means for scraping off and removing the residual toner by pressing one edge of the edge of the cleaning blade made of an elastic material such as rubber against the image carrier is simple in structure, small in size and low in size. It is well known that the toner removing function is excellent in cost and has been widely used in the past.

By the way, when a cleaning blade is used as the cleaning means, it is usual to dispose the edges thereof so as to face each other in the traveling direction of the image carrier (counter system). Although convenient, it is unavoidable that the friction between the image carrier and the cleaning blade becomes large. However, in reality, after the image forming operation is started, most of the toner generated and reaching the position of the cleaning blade is scraped off by this, but a very small amount of toner remains at the blade edge portion, This acts as a lubricant to prevent the edge of the blade from chattering and the blade to be turned over to maintain a smooth cleaning function.

However, for example, when a large amount of toner-consumed images are continuously copied, the amount of residual toner generated is small, and therefore the amount of toner remaining on the blade edge portion and contributing to the lubricating action is also small. Therefore, the friction between the image carrier and the cleaning blade becomes extremely large, and the above-mentioned chattering phenomenon and blade flipping easily occur. Such a situation becomes remarkable at the both ends of the cleaning blade outside the image area.

FIG. 6 shows an example of means for coping with such a situation. In the figure, a cleaning device 2 is arranged in parallel near the image carrier 1 traveling in the direction of arrow A, and one edge of the cleaning blade 3 attached to the cleaning device 2 is the surface of the image carrier 1. Abuts in the counter direction.

Residual toner generated at a transfer portion (not shown) is scraped off by the cleaning blade 3 as the image carrier travels, and is scraped off by the scooping sheet 15 to be guided to the toner storage portion in the cleaning device 2. And further discharged to the outside by the conveying screw 16.

In such an apparatus, in the illustrated case, the toner holding member 14 is disposed so as to face the scooping sheet 15, and the toner storage portion 13 is formed between them.

With this structure, the toner scraped off by the blade 3 is temporarily stored in the toner storage portion 13. Therefore, when images having a low image density are continuously formed as described above, the storage is performed. Since the toner existing in the portion 13 is supplied to the blade edge portion and has a lubricating action, it becomes possible to prevent the blade friction from increasing.

However, if an extremely large number of copies having a low image density are produced, it is inevitable that even if such a toner storage portion is provided, a toner shortage for lubrication will be brought about. Is not an essential solution.

The present invention has been made in view of the above circumstances, and a means for supplying the floating toner collected in the cleaning device is provided at a position corresponding to the outer portion of the image area of the cleaning blade. Then, it is an object of the present invention to provide a cleaning device capable of avoiding the occurrence of a shortage state of toner for lubrication at the blade edge portion and always exhibiting a stable cleaning function.

[0011]

[Constitution of the invention]

In order to achieve the above object, the present invention provides a cleaning device provided with a cleaning blade for abutting against the surface of a running image carrier to remove residual toner from the surface. It is characterized in that a means for guiding an air flow containing floating toner generated in the cleaning device by the traveling of the image bearing member toward both ends of the cleaning blade is provided.

With this construction, the toner for lubrication is insufficient, especially in the vicinity of both ends of the cleaning blade, where it abuts the non-image area of the image carrier, the irregular vibration of the blade edge resulting from this, and the blade. It is possible to effectively prevent the curl and the like.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS "FIG. 1" is a side sectional view of a cleaning device showing an embodiment of the present invention, in which a cleaning device 2 is arranged in parallel in proximity to an image carrier 1 running in the direction of arrow A in the drawing. One of the free edges of the cleaning blade 3 attached to the cleaning device is in contact with the surface of the image carrier in the counter direction.

At the transfer portion (not shown), the residual toner that has not transferred to the transfer material and remains on the image carrier reaches the position of the cleaning blade 3 as the image carrier travels, and is scraped off by this and guided by the scooping sheet 15. The cleaning screw reaches the back of the cleaning device, and the transport screw 1
6 is discharged to the outside.

Around the image carrier 1, a primary charger,
Needless to say, the image signal applying means, the developing device, and other members necessary for image formation are provided, but they are omitted because they are not directly related to the present invention.

In the cleaning device having such a structure, as described above, when a large number of images having a low image density are copied, the toner remaining on the blade edge portion and exerting a lubricating action is insufficient. As a result, irregular vibration of the blade, blade curling, and the like may occur, and in particular, such problems are likely to occur at both end portions of the blade and the portions contacting the non-image area of the image carrier. Further, since urethane rubber, which is often used as a cleaning blade material, has a very large friction with an image carrier using an OPC photoconductor whose surface layer is formed of a polymer resin such as polycarbonate, the above-mentioned problems are caused. It is remarkable.

In order to solve such a problem, the apparatus shown in the figure is characterized in that the air guide member 17 is arranged inside the cleaning device, at a portion substantially facing the cleaning blade 3.

Since the image bearing member runs in the direction of arrow A in FIG. 1 for performing operations such as image formation and transfer, the mark B in the vicinity of it, near the back side of the cleaning blade inside the cleaning device, causes the image bearing member to move. The airflow as shown is generated. On the other hand, most of the toner collected in the cleaning device by the cleaning blade 3 falls toward the scooping sheet 15 due to its own weight, but a considerable part of the collected toner floats in the device due to the presence of the airflow as described above. After that, it gradually sinks under its own weight and falls to the bottom of the device.

In the illustrated apparatus, as described above, the air guide member 17 is provided with a small clearance from the cleaning blade.
Is provided, and a concave surface 17a as described later is formed on the surface on the cleaning blade side to control the air flow direction.

FIG. 2 is an explanatory view showing the relative arrangement of the image carrier 1, the cleaning blade 3, and the air guide member 17, and as shown in the figure, the length of the surface of the image carrier ₁ having the axial length d ₁ is shown. d
There is an image area of ₂ (d ₂ <d ₁ ), and the cleaning blade 3 having a length d ₃ (d ₃ > d ₂ ) is in contact with the blade 3. An air guide member 17 is disposed so as to face the blade 3, and a concave surface 17a having a concave center when viewed from the image carrier side is formed on the side of the air guide member 17 facing the cleaning blade.

Due to this structure, the above-mentioned air flow B hits the concave surface of the air guide member 17 and flows as shown by the arrow C, and along with this, the toner contained in the air flow also flows and the cleaning blade 3 forms an image. It is supplied to the non-image areas ΔD _a and Δd _b at both ends in contact with the carrier, and adheres to the blade edge portion to contribute to the lubricating action. As a result, the toner for lubrication can be positively supplied especially to the non-image areas at both ends of the cleaning blade, so that it is possible to prevent the occurrence of chattering and the blade turning over.

FIG. 3A and FIG. 3B show the amount of toner at both ends of the cleaning blade in the non-image area at both ends with and without the air guide member 17, and the frictional force of the corresponding portion. It is a figure which shows the magnitude. Note that the air guide member is not limited to the one formed in a concave shape as shown in the drawing, and a part of the air guide member may be formed in a spherical shape, or may be formed of a plurality of divided members. It is possible to adopt various configurations capable of sending an air flow to the.

FIG. 4 is a view showing the internal construction of a cleaning device according to another embodiment. As shown in the drawing, a filter 19a, on the side wall of the cleaning device and on the side where both ends of the cleaning blade in the longitudinal direction face each other, Exhaust fans 20a and 20b provided with 19b are provided. With such a configuration, D _a , D _b , E in the cleaning device
_Since airflows indicated by _a and _Eb are generated, the floating toner contained in the airflows is attached to both end portions of the end seals 18a and 18b.
It is also supplied to the portions corresponding to the non-image areas Δd _a and Δd _b at both ends of the cleaning blade 3 in which the blades are provided, and it is possible to avoid the occurrence of blade turning due to an increase in friction due to insufficient toner.

FIG. 5 shows still another embodiment of the present invention. In the case of this apparatus, exhaust fans 20a and 20b are formed on the side wall of the cleaning device, and the same as in the above embodiment. An airflow is generated inside, and an air intake hole 21 provided with a filter 22 is formed in an appropriate place on a wall portion of the cleaning device, that is, a top plate portion in the figure.

As described above, when the air flow is positively generated in the cleaning device by the fan, if the function of the fan is increased so as to supply more toner to both ends of the cleaning blade, the inside of the cleaning device becomes negative. In such a state, the scooping sheet 15 disposed on the upstream side of the blade of the cleaning device and formed of an elastic material such as a mylar sheet is used as shown by a dotted line in FIG. It is inevitable that the toner will be curved to form a gap in the portion, and the toner scraped off by the blade 3 will leak out to contaminate various parts inside the machine, the transfer material and the like.

In this device, the intake hole 21 is provided as described above in order to cope with the above problem, so that air is rapidly sucked from this portion to compensate for the negative pressure in the device. Therefore, it is possible to prevent the scooping sheet 15 from moving away from the surface of the image carrier.

The number and position of the intake holes 21 may be set appropriately so that the air flow inside the cleaning device can easily concentrate the toner contained therein near both ends of the cleaning blade. Of course, an intake fan may be arranged in this portion.

[0028]

As described above, the cleaning blade disposed in the cleaning device is positively supplied with an air stream containing floating toner especially in the vicinity of both ends thereof, and the toner for lubrication is always sufficiently supplied to the edge portion of the portion. Therefore, it is possible to effectively prevent chatter vibration, blade flipping, and the like due to lack of the toner for lubrication at the portion, and always provide a stable and good cleaning function.

[Brief description of drawings]

FIG. 1 is a side sectional view of a cleaning device showing an embodiment of the present invention.

FIG. 2 is an explanatory diagram illustrating a relationship among an image carrier, a cleaning blade, and a baffle member that exhibit the same operation.

FIG. 3A and

FIG. 3B is a diagram showing the difference in the toner amount at the blade end and the magnitude of the frictional force between the blade and the image carrier, with and without the air guide member.

FIG. 4 is a plan view showing the configuration of a cleaning device according to another embodiment.

FIG. 5 is a side sectional view of a cleaning device showing still another embodiment.

FIG. 6 is a side sectional view showing the configuration of a known cleaning device.

[Explanation of symbols]

 1 image carrier 2 cleaning device 3 cleaning blade 15 scooping sheet 16 transport screw 17 air guide member

Claims (4)

[Claims] 1. A cleaning device equipped with a cleaning blade that comes into contact with a surface of a moving image carrier to remove residual toner from the surface, wherein an air flow containing floating toner generated in the cleaning device as the image carrier moves. A cleaning device provided with means for guiding the cleaning blade toward both ends. 2. The cleaning device according to claim 1, wherein the means for guiding the air flow is an air guide member for diverting the air flow. 3. The cleaning device according to claim 1, wherein the means for guiding the air flow is an exhaust fan formed on the wall surface. 4. The cleaning device according to claim 3, further comprising an intake means for compensating the exhaust amount of the exhaust fan.