JP3194335B2 - Cleaning equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cleaning device for scraping toner remaining on the peripheral surface of a photosensitive drum incorporated in a laser beam printer or the like using an electrophotographic process.

[0002]

2. Description of the Related Art In an electrophotographic image forming apparatus such as an electrophotographic copying machine or a laser beam printer, an image is formed by transferring a toner image on a photosensitive drum onto recording paper. Even after the process is completed, a small amount of toner remains on the peripheral surface of the photosensitive drum. If the next process is performed with the toner remaining on the photosensitive drum (hereinafter also referred to as “residual toner”) as it is, image noise such as black spots and streaks will appear and image quality will be reduced. Is provided with a cleaning step of removing residual toner on the peripheral surface of the photosensitive drum.

[0003] There are various types of cleaning devices for cleaning the photosensitive drum, and among them, a blade cleaning device is mainly used. This blade cleaning device presses a blade made of an elastic material such as rubber on the surface of the photosensitive drum and mechanically scrapes the residual toner. Depending on how the blade is pressed against the photosensitive drum, the blade cleaning device shown in FIG. ) As shown in (2),
There are two methods.

One of them is that, as shown in FIG. 4A, the blade 6 is provided on the peripheral surface of the photosensitive drum 5 so that the angle β between the surface 5a of the photosensitive drum 5 and the blade 6 is obtuse. It is a forward blade type with the tip abutting.
First, as shown in FIG. 2B, the tip of the blade 6 is brought into contact with the peripheral surface of the photosensitive drum 5 so that the angle β formed between the cleaning surface 5a of the photosensitive drum 5 and the blade 6 becomes an acute angle. It is a reverse blade method. The forward blade method is also called a counter method, and the reverse blade method is also called a trailing method.

[0005] The cleaning device is required to have a cleaning performance for completely removing the residual toner on the photosensitive drum. In terms of this cleaning performance, a blade cleaning device using a forward blade system, which has a high toner blocking power, is required. Generally, the cleaning device is superior to the cleaning device of the reverse blade type.

By the way, in an electrophotographic image forming apparatus,
When transferring the toner image on the photosensitive drum to the recording paper, if the transfer is performed in a recording paper conveyance path formed substantially in the horizontal direction, a cleaning device and a developing device are provided at left and right positions of the photosensitive drum. Must be arranged, which increases the installation area of the image forming apparatus.

For this reason, a vertical recording paper transport path for transporting the recording paper upward from the bottom is provided, and the toner image on the photosensitive drum is transferred to the recording paper in the vertical recording paper transport path. Various image forming apparatuses have been proposed. According to the image forming apparatus configured as described above, the cleaning device can be disposed above the photosensitive drum and the developing device can be disposed below the photosensitive drum, so that the installation area of the image forming device can be reduced. There is an advantage that you can.

[0008]

However, since the cleaning device is located above the photosensitive drum, the cleaning device uses a blade to remove the scraped toner (hereinafter, also referred to as "removed toner"). It becomes necessary to convey the residual toner from a cleaning unit, which is a part where the residual toner is scraped, to a toner storage chamber, for example. That is, when the cleaning device is disposed at one of the left and right positions of the photosensitive drum, it is sufficient to provide the toner storage chamber below the cleaning unit and drop the removed toner into the toner storage chamber. However, when the cleaning device is located above the photosensitive drum, the toner storage chamber cannot be provided below the cleaning unit because the photosensitive drum is present, and the removed toner is stored from the cleaning unit. It will be necessary to transport it to the room.

In the cleaning device of the type which transports the removed toner, toner clogging occurs in the toner transporting path from the cleaning section to the toner storage chamber, and good cleaning can be continued thereafter. There was a problem that it disappeared.
Therefore, in the conventional cleaning device of this type, in order to prevent the toner from being clogged, a special transport mechanism for forcibly transporting the toner, for example, a rotary driven blade member or the like is provided with a toner transport path. It was provided inside.

[0010] However, the necessity of this special transport mechanism not only complicates the cleaning device but also increases the cost.

SUMMARY OF THE INVENTION The present invention has been made to solve the problems associated with a conventional cleaning device of the type which is disposed above a photosensitive drum and conveys removed toner, and has excellent cleaning performance. Provided is a cleaning device that employs a forward blade system and is located above a photosensitive drum, and that can reliably prevent toner clogging without providing a special transport mechanism for transporting toner. Accordingly, it is an object to achieve simplification of the structure of the cleaning device and cost reduction.

[0012]

In order to achieve the above object, according to the present invention, the blade tip is brought into contact with the peripheral surface of the photosensitive drum so that the angle between the surface to be cleaned of the photosensitive drum and the blade is obtuse. A cleaning device configured to scrape the toner from the photosensitive drum, and a toner transport surface formed by a blade and a holding member that holds the blade, the toner transport surface being disposed to be inclined upward, and the toner transport being provided above the toner transport surface. A casing that forms a toner conveying path together with the surface, and a toner storage chamber having a space that extends below the end of the toner conveying surface;
An inclination equal to the angle of repose of the toner from the horizontal plane including the end
The toner transport path to the virtual surface formed by
A cleaning device, wherein the casing is arranged so as to sequentially spread toward a downstream side .

[0013]

After the toner image on the photosensitive drum has been transferred onto the recording paper, a small amount of toner adheres and remains on the peripheral surface of the photosensitive drum. This residual toner is scraped off by the blade, but since the angle between the surface to be cleaned of the photoconductor drum and the blade is obtuse, the blade has a high force to stop the toner, and the residual toner on the photoconductor drum is completely removed. Is removed. Therefore, even if the next transfer is performed, image noise such as a black point does not appear.
A high quality image is formed.

The toner scraped off from the surface to be cleaned by the blade is conveyed downstream on a toner conveying surface inclined upward. The toner sequentially transported with the continuation of the cleaning accumulates in the toner transport path in a heaping state. When the angle formed by the inclined surface of the accumulated toner with respect to the horizontal plane is equal to or larger than the angle of repose of the toner, the toner in the heaped state naturally collapses from the end of the toner conveying surface to the toner storage chamber. Further, the toner conveyance path is based on at least the angle of repose of the toner.
To a predetermined site determined in accordance with the above. Therefore, the toner is not clogged in the vicinity of the end of the toner conveying surface, and good cleaning is continued.

In order to prevent toner clogging,
Since no special transfer mechanism for toner transfer is provided in the toner transfer path, the cleaning device is not complicated,
There is no increase in cost.

Further, since the removed toner can be guided to the toner accommodating chamber without being clogged, an image is formed by disposing a cleaning device above the photosensitive drum and a developing device below the photosensitive drum. The installation area of the device is reduced.

[0017]

Next, the present invention will be described in detail with reference to the illustrated embodiments. FIG. 1 is a schematic diagram showing the overall structure of a laser beam printer as an example of an image forming apparatus using an electrophotographic process. The left side of the printer main body 11 in FIG. 1 is the front of the printer. This printer body 1
On the bottom side of the printer 1, a sheet accommodating section 12 is built in such a manner as to be inclined downward toward the rear of the printer main body 11, and recording paper is stacked and held on the sheet accommodating section 12. The leading end of the sheet storage unit 12 can be protruded outside the printer main body 11, and when holding a long recording sheet such as a legal size, the leading end of the sheet storage unit 12 is protruded. . In order to regulate the width direction of the recording paper, a width regulating plate 13 is provided in the sheet storage unit 12. A front cover 14 is attached to the printer body 11 so as to be openable and closable so that the recording paper can be easily loaded into the sheet accommodating portion 12.

A laser beam scanning optical system unit 15 is provided at the center of the printer main body 11, and a lid member 17 is attached so as to be swingable around a hinge 16 provided at the rear end of the printer main body 11. In the printer main body 11, the image forming cartridge 2 is positioned below the lid member 17.
0 is detachably mounted. When the image forming cartridge 20 is loaded in the printer main body 11, a pressing member or a spring member (not shown) is attached to the inner surface of the lid member 17 to press the image forming cartridge 20. Further, the lid member 17 is provided with a lock mechanism (not shown). When the lid member 17 is closed, the lid member 17 is locked to the printer main body 11, and when the lock is released, the lid member 17 can be opened.

The recording paper placed on the sheet accommodating section 12 is fed one by one by a paper feed roller 21 and a cam 22 and a pinch roller 23 which comes into contact with the recording paper, and is conveyed while being guided by a guide member. Then, the paper is discharged from the opening 24 formed in the cover member 17 onto the cover member 17 toward the front of the printer.

The image forming cartridge 20 is also referred to as an image cartridge or an image forming unit, and has a photosensitive drum 25 rotatably incorporated in a resin casing. Further, the toner supplied to the photosensitive drum 25 is also stored in a hopper (described later) defined in the casing, and when the toner runs out or the remaining amount of toner is reduced, a new toner is supplied. The image forming cartridge 20 is replaced. Such an image forming cartridge 20 has been developed to reduce the size of an image forming apparatus such as a laser beam printer.

A transfer roller 26 for transferring the latent image formed on the photosensitive drum 25 to recording paper is provided on the printer main body 1.
1 is rotatably mounted. In order to thermally fuse the transfer image to the recording paper, fixing rollers 27 and 28 are attached to the printer main body 11. In order to discharge the recording paper on which the image has been formed onto the cover member 17 through the discharge port 24, a paper discharge roller pair 29 is attached inside the cover member 17. The laser beam printer illustrated in this manner has a vertical recording paper transport path for transporting the recording paper upward from below, and the toner image on the photosensitive drum 25 is transferred in the vertical recording paper transport path. It is designed to transfer to recording paper.

The optical system unit 15 has a polygon mirror 31 to which light from a light source composed of a semiconductor laser (not shown) and a collimator lens (not shown) is applied, and further includes known members such as a folding mirror 32 and a toroidal mirror 33. are doing. The optical system unit 15 irradiates the photosensitive drum 25 with a laser beam transmitted through the glass 34 provided in the window.

FIG. 2 is a schematic sectional view showing the internal structure of the image forming cartridge 20 incorporating the cleaning device according to the present invention.

The image forming cartridge 20 includes an upper casing 4
0 and a lower casing 41. In the cartridge main body, there are provided a developing member storage chamber 42 in which the photosensitive drum 25 and the like are stored, and a toner storage chamber 43 in which toner supplied to the developing member storage chamber 42 is stored. Such a cleaning device 65 is incorporated.

The toner storage chamber 43 is referred to as a hopper, and includes a lower casing 41 and a partition 44 formed integrally therewith.
And a lid-like casing 45 that closes the upper opening, is formed in the cartridge body. An incident opening 48 into which the laser beam from the optical system unit 15 is incident is formed on the tip end surface of the upper casing 40, and an optical path guide 49 extending from the incident opening 48 to the photosensitive drum 25.
Are formed in the cartridge body.

The photosensitive member drum 2 is
5 is rotatably incorporated. A charging brush 47 is in contact with the outer peripheral surface of the photosensitive drum 25, and the outer peripheral surface is charged to a predetermined potential by the charging brush 47. A developing sleeve 51 made of resin is provided on a sleeve driving roller 50 provided adjacent to the photosensitive drum 25, and the developing sleeve 51 is conveyed by a frictional force with an outer surface of the driving roller 50. Then, the drive roller 50 rotates following the rotation of the drive roller 50. The inner diameter of the developing sleeve 51 is slightly larger than the outer diameter of the driving roller 50. A pressing tape 52 for bringing the developing sleeve 51 into close contact with the surface of the drive roller 50 along the direction toward the photosensitive drum 25 is attached so as to slidably contact both ends of the developing sleeve 51 in the axial direction. With this pressing tape 52,
At a position where the developing sleeve 51 contacts the photosensitive drum 25, the developing sleeve 51 is slightly separated from the surface of the drive roller 50 and contacts the photosensitive drum 25 in a bent state.

An electrostatic latent image is formed on the surface of the photosensitive drum 25 by a laser beam, and the toner supplied via the developing sleeve 51 adheres to the electrostatic latent image, and the toner on the surface of the photosensitive drum 25 An image is formed. Then, the toner image is transferred to the recording paper.

In the developing member storage chamber 42, a window 60 is provided.
Is formed along the axial direction of the drive roller 50. The sealing member 59 is made of urethane foam or the like, and its lower frame 5
9 a is located between the lower side of the drive roller 50 and the lower casing 41. The lower frame portion 59a forms a lower seal that presses the lower portion of the developing sleeve 51 against the drive roller 50.

The toner contained in the hopper 43 is fed into the buffer 53, which is a space formed between the seal member 59 and the partition 44, through a toner supply port 54 formed in the partition 44. In order to supply the toner in the buffer 53 to the developing sleeve 51, a blade member 56 having a flat plate shape and a supply roller 57 located at a predetermined gap from the blade member 56 are rotatably provided in the buffer 53. I have. The regulating blade 61 is in contact with the developing sleeve 51 under a predetermined linear pressure in order to regulate the amount of toner attached to the developing sleeve 51 to form a thin toner layer and frictionally charge the toner.

In the hopper 43, there is rotatably provided a toner conveying member 55 for conveying the stored toner to the toner supply port 54 while stirring. The toner conveying member 55 is provided with a film 62 formed of, for example, a flexible polyester film for stirring and conveying the toner.

The cleaning device 65 according to the present invention is based on a blade cleaning system, and has a blade 66 which comes into contact with the peripheral surface of the photosensitive drum 25. The blade 66 is formed of an elastic material such as polyurethane rubber from the viewpoint of excellent abrasion resistance and not adversely affecting the photosensitive drum 25 chemically. Also,
The cleaning device 65 employs a forward blade system, and the tip of the blade 66 is
Is in contact with the peripheral surface of the photosensitive drum 25 such that the angle between the surface to be cleaned 25a and the blade 66 is obtuse. The blade 66 is attached and held by a blade holder 67 (corresponding to a holding member) having a bent shape.

The blade holder 67 is, as shown in FIG.
It has first and second bent portions 68 and 69,
First, second, and third inclined surfaces 71, 72, 73 are provided at boundaries of 8, 69. First inclined surface 71
Is one end 6 located at the right end of the blade holder 67 in the drawing.
7a to the first bent portion 68 is an inclined surface formed to be inclined upward, and the second inclined surface 72 is formed by the first bent portion 68.
The third inclined surface 73 is formed to be inclined upward from the second bent portion 69 to the other end 67b located at the left end in the drawing. It is an inclined surface. The blade 66 is held on the lower surface side of the first inclined surface 71 so as to protrude and extend from the one end 67 a of the blade holder 67. First
The inclined surface 71 is inclined upward at an angle θ with respect to the horizontal plane, and the angle θ is set to a predetermined angle at which the cleaning function by the blade 66 can be suitably performed.

The cleaning device 65 includes the photosensitive drum 25
Therefore, it is necessary to transport the removed toner scraped off by the blade 66 from the cleaning unit 74. Therefore, the blade 66 and the first inclined surface 71 of the blade holder 67 form a toner conveying surface 75 that is arranged to be inclined upward. The upper casing 40 provided above the toner conveying surface 75 forms a toner conveying path 76 for conveying the removed toner together with the toner conveying surface 75. Further, the upper casing 40 also forms a toner accommodating chamber 77 for accommodating the removed toner together with the second and third inclined surfaces 72 and 73.
Since the toner storage chamber 77 is a space extending downward from the first bent portion 68 at the end of the toner transport surface 75, the internal volume of the toner storage chamber 77 is increased, and a larger amount of removed toner can be stored. It is possible.

The upper casing 40 is provided with a thin plate member 78 that comes into contact with the surface of the photosensitive drum 25. The thin plate member 78 allows the residual toner to pass therethrough,
It functions as a seal member that receives the removed toner and does not spill it into the lower space. The toner conveying path 76 and the toner storage chamber 77 are
The blade holder 67 seals the removed toner so that the removed toner does not fly into the image forming cartridge 20.

In the cleaning device 65 of this embodiment, in particular, in the upper casing 40, the interval perpendicular to the toner conveying surface 75 is gradually increased from the cleaning section 74 to the terminal end 68 of the toner conveying surface 75. Is located. Specifically, numerical values are shown as examples. The distance between the upper casing 40 and the toner conveying surface 75 is L1 = 10.4 mm in the vicinity of the cleaning unit 74, whereas the distance between the upper casing 40 and the toner conveying surface 75 is L1 = 10.4 mm. In the vicinity of the first bent portion 68, L2 = 16.0 mm, and the distance gradually increases from the cleaning portion 74 to the first bent portion 68. In other words, the upper casing 40 is configured such that the toner transport path 76 is gradually expanded from the upstream side to the downstream side.
Are located.

The most downstream position where the toner transport path 76 must be sequentially expanded is at least the next position. That is, the position on the most downstream side is from the horizontal plane H including the first bent portion 68 which is the end of the toner conveying surface 75 to the position of the virtual surface N formed with an inclination equal to the repose angle α of the toner. The angle of repose α of the toner is
When the toner is piled up on the horizontal plate, it refers to the angle of the slope with respect to the horizontal plate when the toner naturally breaks down.

Next, the operation of this embodiment will be described.

After the transfer step of transferring the toner image on the photosensitive drum 25 to the recording paper is completed, the residual toner is slightly adhered to the peripheral surface of the photosensitive drum 25. This residual toner is mechanically scraped off by the blade 66 of the cleaning device 65. However, since the cleaning device 65 employs the forward blade system, the blade 66 has a high force for blocking the toner, and the photosensitive drum 25 The upper residual toner is completely removed. Therefore, even if the next transfer step is performed, image noise such as black spots does not appear, and a high-quality image can be formed.

The removed toner scraped off by the blade is guided by the cleaning unit 74 to the toner transport surface 75 so as to be pushed by the removed toner scraped thereafter, and is directed downstream through the toner transport path 76. Transported.

By continuing the cleaning, FIG.
As shown in (1), the removed toner accumulates on the toner conveying surface 75 of the toner conveying path 76 in a heaped state. When the angle formed by the inclined surface of the accumulated toner with respect to the horizontal plane H is equal to or greater than the angle of repose α of the toner, the heaped toner naturally collapses through the second inclined surface 72 to the toner storage chamber 77. Further, the toner transport path 76 sequentially extends from the cleaning unit 74 to at least a predetermined portion determined based on the angle of repose α of the toner. Therefore, the clogging of the toner near the first bent portion 68 does not occur.

Moreover, in order to prevent toner clogging, the cleaning device 65 is not provided with a special transport mechanism for transporting toner.
Is not complicated and does not increase the cost.

Further, since the laser beam printer of this embodiment has a recording paper conveying path in the vertical direction, the cleaning device 65 can be arranged above the photosensitive drum 25 and the developing device can be arranged below. The installation area of the laser beam printer can be saved.

[0043]

As described above, according to the present invention,
A cleaning device that employs a forward blade system with excellent cleaning performance and is located above the photosensitive drum,
Without providing a special transport mechanism for transporting the toner, it is possible to provide a cleaning device that can reliably prevent the occurrence of toner clogging, thereby achieving simplification of the structure of the cleaning device and cost reduction. Becomes

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an overall structure of a laser beam printer as an example of an image forming apparatus using an electrophotographic process.

FIG. 2 is a schematic sectional view showing the internal structure of an image forming cartridge incorporating the cleaning device according to the present invention.

FIG. 3 is a schematic sectional view showing a main part of the cleaning device according to the present invention.

FIGS. 4A and 4B are diagrams for explaining two types of blade cleaning devices.

[Explanation of symbols]

 25 photoconductor drum 25a cleaning surface 40 upper casing (casing) 65 cleaning device 66 blade 67 blade holder (holding member) 68 first bent portion (end of toner transport surface) 69 second bent Unit 71: First inclined surface 72 ... Second inclined surface 73 ... Third inclined surface 74 ... Cleaning unit 75 ... Toner transport surface 76 ... Toner transport path 77 ... Toner storage chamber H ... Horizontal plane including the end of toner transport surface N ... Virtual Surface α: angle of repose of toner

──────────────────────────────────────────────────続 き Continuation of front page (72) Inventor Hideyuki Yoshida 2-3-113 Azuchicho, Chuo-ku, Osaka-shi Osaka International Building Minolta Camera Co., Ltd. JP-A-5-297715 (JP, A) JP-A-5-11600 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03G 21/10-21/12

Claims (1)

(57) [Claims] 1. A cleaning device for scraping toner from a photosensitive drum by bringing a blade tip into contact with a peripheral surface of the photosensitive drum so that an angle formed between a surface to be cleaned of the photosensitive drum and the blade is an obtuse angle. A toner conveying surface formed by a holding member that holds the blade and disposed to be inclined upward; a casing provided above the toner conveying surface to form a toner conveying path together with the toner conveying surface; and the toner conveying surface. And a toner storage chamber having a space extending below the end of the toner conveying surface.
Toner transport path to virtual surface formed with a new inclination
Wherein the casing is arranged such that the casings sequentially spread from the upstream side to the downstream side .