JPH06324610A - Brush cleaning device - Google Patents

Abstract

PURPOSE:To efficiently remove developer retaining at the base part of brush bristles and to obtain high cleaning performance for a long period by providing many brush bristles around a specified rotating arbor, thereby constituting a cleaning brush roller. CONSTITUTION:The fur brush roller 61 has a core bar 611 functioning as the arbor and many brush bristles 612 provided on the peripheral surface of the core bar 611. The core bar 611 is formed to be a hollow cylinder, and its hollow part is made an inside vent path 611a, then many vent holes 611b are dispersedly formed on its peripheral wall, and the vent path 611a is allowed to communicate with the outside of the core bar through the vent holes 611b. As to the brush bristles 612, fiber 612a for brush bristles is woven in ground fabric 612b so that a brush part 612c may be formed, and the brush cloth 612c is wound and stuck to the periphery of the core bar 611. The vent hole 611b of the core bar 611 is formed by performing punching work to the core bar 611 together with the brush cloth 612c wound and stuck in such a way.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic copying machine,
The present invention relates to a brush cleaning device for cleaning an electrostatic latent image carrier used in an image forming apparatus such as a printer.

[0002]

2. Description of the Related Art According to an image forming apparatus such as an electrophotographic copying machine or a printer, the surface of an electrostatic latent image bearing member is charged by a charging device, and an optical system exposes an image corresponding to a document image in the charging area. Then, an electrostatic latent image is formed, and the electrostatic latent image is developed by a developing device to become a visible image, which is transferred onto a transfer material by a transfer device and fixed by a fixing device. After the transfer of the visible image, the developer remaining on the electrostatic latent image carrier is cleaned and removed by the cleaning device.

As such a cleaning device, various types are known, but generally, the residual developer is cleaned by contacting the surface of the electrostatic latent image bearing member and moving relative to the surface. Those to be removed are widely known, and representative examples thereof include one in which a cleaning blade is brought into contact with the surface of the electrostatic latent image carrier and one in which a rotating cleaning brush roller is brought into contact with the surface of the electrostatic latent image carrier. it can.

Among them, the one using the cleaning blade is apt to wear the surface of the electrostatic latent image bearing member due to the blade edge to cause surface roughness, and to increase the moving speed of the surface of the electrostatic latent image bearing member. In this case, there is a problem that it is difficult to deal with the problem, and residual toner is likely to collect at the blade edge and easily aggregate. In this respect, the brush roller is easy to solve the above problems in the blade cleaner.

[0005]

However, the cleaning device using the cleaning brush roller still has the following problems. That is, generally, the cleaning brush roller BR removes the residual developer by some processes as shown in FIG. First
In the process of, the rotating brush bristles f scrape off the developer d1 on the electrostatic latent image carrier PC and discharge it in the direction of. The second process is the electrostatic latent image carrier PC
The developer d1 above is once taken into the brush, and when the brush b f hits the scraping plate p, the developer d2 in the brush is knocked out in the direction of. In the third process, like the second process, the brush bristles f hit the scraping plate p, the brush bristles f bend as the brush roller BR rotates, and when the brush bristles straight again, the developer d2 Is played in the direction of. The above-mentioned three processes are main, but in addition, when the brush bristles f come into contact with the electrostatic latent image carrier PC, the developer d2 in the brush is caused by centrifugal force or the like.
Are removed.

Originally, it is necessary to remove almost 100% of the residual developer on the electrostatic latent image carrier PC in the first to third processes, but there are several causes that are downstream of the brush roller BR. In many cases, a large amount of developer d3 escapes, causing a problem. Therefore, the brush roller BR
Further, a cleaner for blades and brushes is provided on the downstream side, but this has many problems such as an increase in cost, an increase in occupied space, and easy occurrence of another trouble.

For example, even if a blade or a brush is provided on the downstream side, the cleaning condition of the main brush roller BR is suitable for it, and if the condition is not maintained for a long time, after all, The load on the blades and brushes on the downstream side increases, and even these cannot be cleaned sufficiently. That is, it is necessary for the brush roller BR to maintain the initial state as much as possible.

The problems of the brush roller BR are as follows. First, as a first problem, there is a phenomenon that the residual developer d1 on the electrostatic latent image carrier PC cannot be completely removed, and the developer d1 directly escapes to the downstream side. This may be in the initial case or after printing endurance (after image formation). In the initial case, since the cleaning ability is fundamentally insufficient, it is necessary to review the brush roller BR as a whole.

However, after printing, the cause is something that changes with time. For example, the contact amount due to abrasion of the brush bristles is reduced, the contact force due to the collapse of the brush bristles f is reduced, and the developer trapping ability is reduced due to an increase in the retained developer in the brush roller. The second problem is the phenomenon of redeposition of the developer from the brush roller BR to the electrostatic latent image carrier PC. This is because the ability to remove the developer from the brush roller is insufficient, and when it is considerably insufficient, it occurs from the beginning, and it is easy to mistake as the first problem. At the same time, the amount of redeposition increases, which becomes a problem.

In the first problem, if this occurs from the beginning, it is necessary to review the system itself, but if it occurs after printing, a durable brush bristle material is used to suppress the change over time of the brush roller BR. Or, the method of weakening the hitting power is taken. However, the brush bristle material must give the highest priority to cleaning ability, and the stronger the material, the easier it is to damage the electrostatic latent image bearing member, so there is a limit to the selection of the material. If the contact force is weakened, problems such as insufficient cleaning ability and ability to remove the developer from the brush roller BR occur.

As for the second problem, the brush roller B
There is a method of increasing the amount of the scraping plate p or increasing the number of the scraping plates p in order to enhance the developer removing ability in the R, but in either case, the brush bristles f are easily damaged. Further, there are problems in terms of cost and space, such as a method of positively sucking with air or the like and a method of sucking and removing with a roller to which a bias is applied.

Therefore, in the present invention, the surface of a charged electrostatic latent image bearing member is imagewise exposed to form an electrostatic latent image, the latent image is developed into a visible image, and the visible image is transferred. A brush cleaning device for cleaning and removing the residual developer used in an image forming apparatus for transferring and fixing onto the electrostatic latent image bearing member after the transfer of the visible image onto the electrostatic latent image bearing member. In particular, the second problem can be solved, that is, the developer taken into the cleaning brush roller in the cleaning device does not require a special increase in space and cost, but it is better than the conventional cleaning device of the same type. Can also be removed efficiently, especially the developer that may accumulate at the root of the brush bristles or that can be removed efficiently, thereby maintaining high cleaning performance for a long period of time. And to provide a cleaning apparatus.

[0013]

The brush cleaning device of the present invention for solving the above-mentioned problems is provided with a cleaning brush roller, and the roller is provided with a large number of bristles around the rotary core rod. The core rod is characterized by having an internal ventilation passage and a large number of ventilation holes communicating from the internal ventilation passage to the brush bristle root portion.

As the brush bristle material used for the brush roller, nylon, rayon, acrylic, Teflon,
In addition to resin fibers such as polypropylene and polyester, it is possible to exemplify conductive fibers or carbon fibers in which a conductive material such as carbon is dispersed, and examples of the shape include straight hair state, loop state, spun yarn and the like. can do. On the other hand, as the core rod of the brush roller, a typical pipe-shaped one made of metal, resin or the like and having a hollow inside for providing a ventilation path can be mentioned. Regarding the efficiency of removing the developer in the brush roller (the amount of developer removed by the toner removing operation / the amount of developer in the initial brush roller), the ventilation hole provided in the core rod has an opening ratio as shown in FIG. The larger the number of vent holes is, the better, but conversely, there is a problem that the cleaning ability is reduced due to a decrease in the area of brush bristles. Therefore, the opening ratio is at least 5% or more and the number of ventilation holes is 1 as long as the cleaning ability is not deteriorated.
It is desirable that the number is 4 or more per cm ² .

[0015]

According to the brush cleaning apparatus of the present invention, since the core rod of the cleaning brush roller has the internal ventilation passage and the numerous ventilation holes communicating from the ventilation passage to the root portion of the brush bristle, the brush roller rotates. By doing so, an air flow that flows in the vent hole of the core rod and the brush bristle root portion close to it is generated, and by this air flow, the developer that is taken into the brush roller and tends to stay in the brush bristle root portion is scattered outward, As a result, the developer can be smoothly removed from the brush roller by a means for removing the developer taken into the brush roller from the brush roller (for example, a scraping plate contacting the brush roller).

[0016]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a schematic configuration of an image forming apparatus including a brush cleaning device 6 which is an embodiment of the present invention. The image forming apparatus shown in FIG. 1 is a copying machine and includes a photosensitive drum 1. Around the photosensitive drum 1, a charging charger 2, an inter-image eraser 8, a developing device 3, a transfer charger 4, a separation charger 5, a brush cleaning device 6 and an eraser 7 are sequentially arranged. The photoconductor drum 1 and the developing device 3 are each driven by a motor (not shown).

Above the photoconductor drum 1, there is an optical system 9 for scanning a document image and performing image exposure L corresponding to the document image on the surface of the photoconductor drum 1. There is a paper feed unit (not shown) on the upstream side of the transfer charger 4, from which the transfer paper S is sent to the timing roller pair T and further to the transfer area.
A fixing device (not shown) is provided on the downstream side of the separation charger 5, and a discharge roller and a discharge tray (not shown) are further provided on the downstream side.

According to the copying machine described above, the surface of the photosensitive drum 1 rotated by a motor (not shown) is charged by the charging device 2, and the charged area is subjected to image exposure L from the optical system 9 to form an electrostatic latent image. Are formed, and the inter-image eraser 8 subsequently erases the electric charge between the images. This electrostatic latent image is developed by the developing device 3 into a toner image, which reaches the transfer area.
On the other hand, the transferred transfer paper S is transferred by the timing roller pair T to the transfer area in synchronism with the toner image on the photosensitive drum 1, and the transfer charger 4 transfers the toner image. The transfer paper S to which the toner image is transferred is separated from the photosensitive drum 1 by the separation charger 5, the toner image is fixed, and then the transfer paper S is ejected to the outside of the machine. After the toner image is transferred, the developer remaining on the surface of the photosensitive drum 1 is cleaned and removed by the cleaning device 6 and taken into the cleaning device.

The developer thus collected in the cleaning device 6 is carried out of the cleaning device by driving the carrying coil 60 provided in the device by a driving means (not shown). The image forming process has been described above. Now, the details of the cleaning device 6 according to the present invention will be described.

As shown in FIG. 1, the cleaning device 6 is provided with a fur brush roller 61 and a flicker 62 that slightly bites into contact with the roller 61, and further, the roller 61 in the CCW direction of the surface movement of the photosensitive drum 1.
The carrying coil 60 is provided on the upstream side of the roller 61, and the cleaning blade 63 that abuts on the surface of the photosensitive drum 1 is provided on the downstream side of the roller 61.

The fur brush roller 61 is shown in FIGS.
As shown in FIG. 5, it has a core metal 611 as a core rod and a large number of brush bristles 612 provided on the peripheral surface thereof. Core metal 6
11 is rotatably supported by a bearing (not shown) in the cleaning device casing 64, and is rotationally driven in the same CCW direction as the photosensitive drum 1 in FIG. 1 by a driving unit (not shown).

As shown in FIG. 2, the core metal 611 is formed in a hollow cylindrical shape, and the hollow portion has an internal ventilation passage 611a.
A large number of ventilation holes 611b are dispersedly formed in the peripheral wall, and these ventilation holes communicate the ventilation path 611a with the outside of the cored bar. As shown in FIG. 2, the brush bristles 612 are formed by weaving a fiber 612a for brush bristles into a base cloth 612b to form a brush portion 612c, and using the brush cloth 612c as a core metal 611.
It is provided by wrapping and adhering around.

The vent hole 611b of the core metal 611
Is formed by punching the core metal 611 together with the brush cloth 612c thus wound and adhered. Note that FIG.
As shown in FIG. 5, a core metal 611 is preliminarily perforated to form a large number of ventilation holes 611b, and the brush cloth as described above is formed into a belt shape. It is also conceivable that the surface of the gold 611 is spirally wound and fixed by adhesion.

It is also conceivable to directly implant the brush bristles 612 on the surface of the cored bar 611 in which the ventilation holes 611b are formed by using an adhesive. In any case, in this type of brush roller 61, as shown in FIG. 4 (A), a part X of the brush bristles 612 group is brought into contact with the surface of the photosensitive drum 1, and as in the conventional case, The flicker 62 is slightly bited into contact with the flicker 62, and in this state, the core metal 611 is rotationally driven in the direction of the arrow CCW by a driving unit (not shown), so that a process similar to that of the conventional cleaning brush roller BR shown in FIG. The residual toner on the surface of the body drum 1 is cleaned and removed.

According to the brush roller 61,
Since the core rod 611 has the internal ventilation passage 611a and the large number of ventilation holes 611b communicating from the ventilation passage to the root portion of the brush bristles 612, the brush roller 61 rotates, so that FIG. As shown in, the airflow Ai goes in and out of the vent hole 611b of the core rod, and the airflow naturally flows to the root portion of the brush bristles 612, and is taken into the brush roller 61 by this airflow and stays at the root portion of the brush bristles. As a result, the toner taken in by the brush roller 61 is elastically restored from the flicker 62 and the bending of the brush bristles, and the like.
Released smoothly from.

Such a ventilation hole 61 is formed at the root of the brush bristle.
In the conventional brush roller BR not provided with 1b, as shown in FIG. 4 (C), the air flow to the brush roller BR only flows on the roller surface portion, so that the toner easily accumulates at the brush bristle root portion. In addition, although the toner that has once stagnated is difficult to be released, the brush roller 61 according to the present invention does not easily stagnant toner at the root portion of the brush bristles 612, so that the brush roller 61 is always in the initial state. It is easy to maintain the state of, and the cleaning ability can be maintained in the initial good state.

Even if there is toner that slips through the brush roller 61, the toner that slips through is
It is scraped off by the cleaning blade 63 on the downstream side of the roller 61. Next, still another example of the brush roller that can be used in the cleaning device of the present invention will be described with reference to FIGS.

In the brush roller 65 shown in FIG. 5, as shown in FIG. 5A, the roller core rod is formed from a mesh pipe 651. By using a mesh-shaped pipe as the core rod in this manner, the opening efficiency of the roller core rod and the number of ventilation holes are increased without reducing the brush bristle density,
The toner removal efficiency in the brush roller is improved.

The roller core rod 651 made of the mesh pipe is formed by weaving a metal wire having high strength here, and the brush bristles 652 are bundled with a plurality of bristles and are shown in FIG. As shown in FIG. 5, the wires 651w are regularly sandwiched at the intersecting portions. Brush bristles 65
In addition to this, as a method of providing 2, a breathable brush cloth is obtained by weaving a brush fiber, which becomes the brush bristles, into a breathable base cloth, and this brush cloth is a mesh pipe core rod 651.
It is also conceivable to wind it around and adhere it. In addition, such a breathable brush cloth can be used for forming the above-described brush roller 61.

As the mesh-shaped pipe for providing the roller core rod 651, in addition to the above-mentioned ones, it is also conceivable that the mesh-shaped pipe is made of a thin metal plate or a metal pipe in which mesh-like ventilation holes are formed by etching, punching or the like. in this case,
As a method of providing the brush bristles 652, it is conceivable to directly implant the brush fibers to be the brush bristles with an adhesive or the like on the mesh-shaped metal plate or the pipe.

The brush roller 66 shown in FIG. 6 has a core rod ventilation hole 661b extending from the internal ventilation passage 661a of the roller core rod 661.
The core rod 661 is provided with an air discharge fin 661c for forcibly generating an air flow flowing through the root of the brush bristles 662. In the example shown in FIG. 6, each fin 661c
Extends from the edge of each ventilation hole 661b toward the internal ventilation passage 661a.

Although the fins 661c are not necessarily provided for each vent hole, they are evenly provided for each vent hole in order to surely prevent the backflow of the air flow and prevent the toner from being fed into the brush again. Is desirable. Further, in order to smooth out the exhaust air by the fins 661c, an air introduction hole or an intake hole 661d which allows the air to flow into the internal ventilation passage 661a may be provided at a portion outside the brush bristle group of the core rod 661.

The method for providing the air discharge fins, the position for providing the air discharge fins, etc. are not limited to those in the illustrated example, but the core rod 661 is provided.
If it is provided inside, the extra space for providing the fin is not required separately. In addition, since fins and ventilation pipes are not required separately, the manufacturing cost can be suppressed. Figure 6
According to the brush roller 66 shown in FIG. 6, when the brush roller 66 is rotated as shown in FIG.
Since the forced airflow Ai is generated from 1a to the root portion of the brush bristles 662 through the ventilation hole 661b and further toward the outer circumference of the roller, the toner removal efficiency is improved accordingly. When the brush roller is stopped, the fin 661c is also stopped, so that unnecessary air flow is not generated.

The brush roller 67 shown in FIG. 7 is provided with a fan 671c at the end of the internal air passage 671a of the roller core rod 671 instead of the air discharge fin 661c of the brush roller 66 shown in FIG. An outside air introduction hole 671d is provided in a portion further outside the fan 671c and outside the group of brush bristles 672. According to this brush roller 67, the fan 671c
Also rotates, and the core rod ventilation hole 671b from the internal ventilation passage 671a
The air Ai is forced to flow toward the root of the brush bristles 672, and further toward the outer circumference of the roller, whereby the toner in the brush is discharged. The brush roller 67 has the same advantages as the roller 66.

It is also conceivable to use the above-mentioned air discharging fin together with the fan 671c. In the brush rollers 66 and 67 shown in FIG. 6 and FIG. 7, the outside air introduction holes or the intake holes 661d and 671d are not particularly limited to that position as long as the outside air can be smoothly introduced into the air passage inside the core rod. However, in order to reliably prevent the toner that becomes dust in the cleaning device casing 64 from being sucked into the roller core rod again, the core rod may be projected outside the casing and provided outside the casing. desirable.

In the case of the brush roller shown in FIGS. 6 and 7, the material, structure, and method of the core rod, the material, structure, and provision of the brush bristles are the same as those described before those rollers. The same as in the case of rollers. In any of the above brush rollers, as shown in FIG. 9, the portion X of the brush bristle group F that contacts the photosensitive drum 1 rubs the surface of the drum 1, collides with the flicker 62, and passes through it. By doing so, the residual toner on the drum surface is removed, and the toner taken into the brush roller at that time is mainly subjected to the above-mentioned action of the air flow and flicker before the portion X reaches the contact position with the drum 1 again. Although it is released to the outside of the brush roller by the action of 62, the shielding member B is provided in the air passage W in the roller core rod in order to more surely prevent the toner that has not been released at that time from adhering to the drum 1 again. Is provided to prevent the air flow from being easily generated in the vent hole of the roller core rod at the portion where the photoconductor drum 1 and the brush bristle group contact each other.
At the portion where the toner is removed from the brush roller on the downstream side of the contact portion between the photoconductor drum 1 and the brush bristles F, the air outflow passage is narrowed to make the airflow in the core rod ventilation hole faster and to easily blow the toner away. You may.

Although the flicker 62 is not always necessary, the presence of the flicker 62 allows smooth and reliable removal of toner from the brush roller.

[0038]

As described above, according to the present invention, the surface of a charged electrostatic latent image bearing member is imagewise exposed to form an electrostatic latent image, and the latent image is developed into a visible image, For cleaning and removing the residual developer used in an image forming apparatus for transferring and fixing the visible image on a transfer material and cleaning and removing the developer remaining on the electrostatic latent image carrier after the transfer of the visible image. In the brush cleaning device of the present invention, the developer taken into the cleaning brush roller in the device can be removed more efficiently than in the conventional cleaning device of the same kind without requiring an extra space or cost increase. It is possible to provide a brush cleaning device that can efficiently remove the developer that has accumulated or may accumulate at the root of the brush bristles, and that can maintain high cleaning performance for a long period of time. .

[Brief description of drawings]

FIG. 1 is a diagram illustrating a schematic configuration of an image forming apparatus that employs a cleaning device according to an embodiment of the present invention.

FIG. 2 is a perspective view showing a part of a cleaning brush roller in the cleaning device shown in FIG. 1 with a part of the brush bristles omitted.

FIG. 3 is a partial front view of another example of the brush roller.

FIG. 4A is an explanatory diagram of a usage state of the brush roller shown in FIGS. 2 and 3, FIG. 4B is a diagram showing an air flow generated in the roller, and FIG. It is explanatory drawing of the airflow when not providing a ventilation hole in a roller core rod.

FIG. 5A is a perspective view showing a part of still another example of the brush roller, omitting part of the brush bristles;
FIG. 6B is a diagram for explaining how to provide brush bristles in the roller shown in FIG.

FIG. 6A is a front view showing a part of still another example of the brush roller, omitting a part of the bristles of the brush roller and a part of the core rod, and FIG. FIG. 6 is an explanatory diagram of an air flow generated in the roller shown in FIG.

FIG. 7 is a front view showing a part of still another example of the brush roller in a partial cross section.

FIG. 8 is a schematic cross-sectional view of still another example of the brush roller.

FIG. 9A is a graph showing the relationship between the vent hole opening rate of the brush roller core rod and the toner removal efficiency from the inside of the brush roller, and FIG. 9B is the graph showing the number of vent holes of the brush roller core rod. 6 is a graph showing the relationship of toner removal efficiency from the inside of a brush roller.

FIG. 10 is a diagram illustrating a process of cleaning and removing residual developer from the electrostatic latent image carrier by a conventional brush roller.

[Description of Reference Signs] 1 Photoconductor drum 2 Charging device 3 Developing device 4 Transfer charger 5 Separation charger 6 Cleaning device 60 Toner conveying coil 61, 65, 66, 67 Cleaning brush roller 611, 651, 661, 671 Brush roller core rod 611a , 661a, 671a Vent path inside core rod 611b, 661b, 671b Vent hole in core rod 612, 652, 662, 672 Brush bristles 62 Flicker 63 Cleaning blade 7 Eraser 8 Inter-image eraser 9 Optical system

Claims (1)

[Claims] 1. An electrostatic latent image is formed on a surface of a charged electrostatic latent image carrier by imagewise exposure, the latent image is developed into a visible image, and the visible image is transferred onto a transfer material. A brush cleaning device for cleaning and removing the residual developer after the transfer of the visible image, which is used for an image forming apparatus for cleaning and removing the developer remaining on the electrostatic latent image carrier, the cleaning brush The roller is provided with a large number of bristles around the rotary core rod, and the core rod has an internal ventilation passage and a large number of communicating from the internal ventilation passage to the brush bristle root portion. A brush cleaning device having a ventilation hole.