JP2001282006A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a cleaning device for a belt type traveling body which can rock to obtain stable cleaning performance even when the belt type traveling body is rocked. SOLUTION: This image forming device is provided with the cleaning device 14 attached to the supporting frame body of a transfer carrying belt 9 and equipped with a cleaning blade 16 rubbing the belt 9 so as to remove toner adhering to the surface of the belt 9, and the blade 16 abuts on the opposed position of a driving roller 12 holding the belt 9 and the supporting frame body of the belt 9 is rocked centering the roller 12 to which the blade 16 is opposed. Even when it is rocked in the midst of driving the belt 9, the speed control of the belt 9 is performed so that the relative speed of the belt 9 to the belt 16 may be constant.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus using an electrophotographic process, such as a copying machine and a printer, and more particularly to a cleaning device for a belt-like traveling body in an image forming apparatus.

[0002]

2. Description of the Related Art In recent years, multifunction peripherals having all output terminals such as copiers, printers, and facsimile machines have been widely accepted in the market. An image forming apparatus using an electrophotographic process has been widely accepted as such a network-compatible output terminal.

In such an image forming apparatus, digitization has progressed from a conventional analog machine, and it has been a problem that the cost of the main body of the digital machine is equivalent to or less than that of the analog machine. Further, in recent years, black-and-white machines have been mainly used in copiers and printers in the past, but in offices, the use of originals or output files in full color has been rapidly increasing. It is becoming an issue to make not only a digital machine equivalent to the analog machine but also a main body cost and a running cost equivalent to a monochrome machine. For that purpose, a technology capable of dramatically reducing the TCO (total required cost as viewed from the user) is desired. That is,
In addition to efforts to reduce the cost of the main body, it is essential to reduce the so-called running cost to extend the service life in order to realize a total cost reduction.

[0004] One of the specific examples is an interval of replacement or inspection of the cleaning device. In an electrophotographic image forming apparatus that forms an image on a transfer material with toner, it is undeniable that very little toner cannot be used for the transfer material. If the very small amount of toner is not sufficiently removed, not only will it lead to image defects due to repeated image formation, but it will also hinder proper operation of devices such as a drive unit due to accumulation of toner inside the device. Further, not only the toner but also residues such as paper dust generated by using a transfer material such as paper cause a problem. Improvements have been made to reduce the residual toner to improve the utilization, but they cannot be completely eliminated and require cleaning. Stably operating the cleaning device for a longer period reflects the running cost of the device.

For example, in a conventional full-color copying machine provided with a transfer belt that carries and conveys a transfer material and sequentially superimposes and transfers the toner image formed on the image carrier onto the transfer material,
A cleaning device is provided for removing toner adhered to the surface of the transfer belt. A conventional electrophotographic image forming apparatus forms an electrostatic latent image on an image carrier by charging an image carrier, performing exposure and writing according to an image signal using a semiconductor laser, an LED, or the like. Thus, the electrostatic latent image is visualized to form a toner image, and the toner image is transferred to a transfer material such as transfer paper or a film directly or via an intermediate transfer member. Then, the transfer material onto which the toner image has been transferred is transported to a fixing device, and the toner image is fixed on the transfer material by the fixing device to obtain an image. In this apparatus, the elements from which the toner must be removed include, in addition to the above-described image carrier, an intermediate transfer body or a transfer belt as a belt-like traveling body.

As described above, with the progress of full-color image forming apparatuses, recent image forming apparatuses use a belt-like traveling member such as the above-mentioned intermediate transfer member or transfer belt to have a plurality of image carriers. To take is getting more. Various cleaning means have been conventionally proposed as a cleaning means for removing the toner adhered to the surface of the belt-like traveling body. It is well known that such a device that removes and removes adhered toner by contacting it has a simple configuration, is low in cost, and has an excellent adhered toner removing function. .

Further, the demand for higher definition and higher image quality of copiers has been increasing at the same time as the cost has been reduced. In this technical field, attempts have been made to achieve higher image quality by reducing the particle size of toner. I have. For this purpose, the toner has been reduced in particle size and sphere. Higher definition images can be obtained by reducing the particle size of the toner, and the contact area with the image carrier is reduced by using a spherical toner, so that the transfer to the transfer material is efficient. And the amount of remaining toner can be reduced.

Further, in the above-mentioned belt-shaped traveling body, a configuration having a swing mechanism is known. This is because the belt-shaped traveling body itself can be operated only at a certain rotation angle with respect to the center of rotation, thereby making it easier to control and operate the belt-shaped traveling body, for example. This has the effect of preventing various members from deteriorating due to the application of excessive stress. Further, by bringing the cleaning blade into contact with a driving roller that drives the belt-shaped traveling body, a belt-shaped traveling body that runs stably for a long time without causing slippage of the belt can be obtained.

[0009]

However, in a cleaning device attached to a support frame that holds a transfer belt, which is a belt-like traveling body, a cleaning blade is brought into contact with a roller at a position facing the roller, and the roller is belt-shaped. In a configuration in which the driving roller is a driving roller of the traveling body, and the driving roller is fixed independently of the swing of the supporting frame of the belt-shaped traveling body, the cleaning blade cleans the surface of the belt-shaped traveling body with a cleaning blade. When the frame itself supporting the belt-shaped traveling body operates when the belt-shaped traveling body swings, the state of contact of the cleaning blade with the belt becomes unstable, and the ability to clean the belt during the swinging decreases. Problem arises.

More specifically, for example, when the cleaning device fixed to the support frame of the belt-shaped traveling body moves together with the belt-shaped traveling body during swinging, the contact state of the cleaning blade is changed. Further, as shown in FIG. 3, if the drive roller is regulated so as not to rotate during lift-up / lift-down, which is a swing motion of the transfer belt, the relative position between the transfer belt and the cleaning blade is displaced. That is, in the case of the configuration as shown in FIG. 3, the contact state of the cleaning blade is such that the transfer belt rotates in the reverse direction with respect to the rotation direction of the drive roller with respect to the cleaning blade when lifting up, and rotates forward when lifting down. An unstable state occurs at the start of image formation. For this reason, only the position where the cleaning blade is in contact at the time of starting the belt cannot be cleaned, so that the toner remains and so-called cleaning failure may occur.

Further, if the cleaning blade is kept in contact with the belt-like traveling body for a long period of time and driven, the distortion may easily accumulate on the cleaning blade, causing a problem such as turning up the blade.

To cope with such a problem, it is conceivable to increase the pre-rotation at the time of image formation and pass the blade at the stationary position before image formation so that the image formation is not affected by the cleaning failure. An increase in the pre-rotation time is not desirable in terms of the performance of the device.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a cleaning device for a swingable belt-like traveling body that can obtain stable cleaning performance even when the belt-like traveling body swings.

[0014]

In order to achieve the above-mentioned object, a typical construction of the present invention is to attach a support frame of a seamless belt-like running body and rub against the belt-like running body. A cleaning device provided with a cleaning blade for removing toner adhered to the surface thereof, wherein the cleaning blade abuts against a position facing one of the rollers holding the belt-shaped traveling body, and supports the belt-shaped traveling body. In an image forming apparatus in which a frame body can swing around a roller opposed to the cleaning blade, the relative speed of the belt-like running body to the cleaning blade is constant even during swinging during driving of the belt-like running body. The speed control of the belt-shaped traveling body is performed so that

Specifically, for example, the speed of a driving roller for driving the belt-shaped traveling body to rotate is increased by the swing rotation speed during the lifting of the belt-shaped traveling body,
During lift-down, the rotation speed is reduced by the swing rotation speed.

Further, the invention is characterized in that the belt-shaped traveling body is fixed during non-image formation, and an operation of swinging the support frame of the belt-shaped traveling body is performed.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of an image forming apparatus to which the present invention is applied will be described in detail with reference to the drawings.

[First Embodiment] FIG. 1 is a schematic sectional view of an image forming apparatus according to a first embodiment of the present invention, and FIG. 2 is a side sectional view of a cleaning apparatus according to the present embodiment.

(Image Forming Apparatus) The image forming apparatus shown in FIG. 1 is an electrophotographic copying machine for forming an image on a recording medium in accordance with an image signal sent from a computer or the like (not shown). In each image forming unit of the image forming apparatus, the image carrier 1 is uniformly charged by the charging unit 2,
The laser oscillator emits a light beam according to the image signal. An electrostatic latent image is formed on the portion of the image carrier 1 where the light beam is irradiated, and is developed by a developing means 3 with toner as a developer to be visualized.

A transfer material, which is a recording medium, is loaded on the cassette 6, is separated and fed one by one by a feed roller 7, and after skew is corrected by a pair of registration rollers 8, a belt-like traveling body is formed. And is conveyed to the image carrier 1. The image carrier 1 provided with the charging means 2 and the developing means 3 is tandem for four colors (in this embodiment, the part a is yellow Y, and the part b is magenta M, c
The toner image carried on the image carrier 1 is transferred by the transfer means 5 to the transfer material conveyed by the conveyance belt 9, and is fixed. After being sent to the means 11 and subjected to heat and pressure to fix the image, it is discharged outside the apparatus. The image carrier 1 on which the toner image has been transferred to the transfer material is cleaned by the image carrier cleaning means 4 and is used for the next image formation. The toner remaining on the transport belt 9 after transporting the transfer material to the fixing unit 11 is removed by the cleaning device 14 and is again provided for transfer transport for image formation.

The toner used in the present embodiment has a polymer toner prepared by a suspension polymerization method comprising a core containing an ester wax, a resin layer comprising styrene-butyl acrylate, and a surface layer comprising styrene polyester. A mixture with a resin magnetic carrier prepared by a legal method was used as a two-component developer.

(Belt-like traveling body) The material of the transfer / conveying belt 9 as the belt-like traveling body used in the present embodiment is a polyimide resin containing carbon for resistance adjustment. Numerous polystrimers and elastomers such as polyvinylidene fluoride resin, polycarbonate resin and polyurethane resin may be used as the material.

The support frame of the transfer / conveyance belt 9 has two rollers, and comprises a drive roller 12 for driving the belt by frictional force and a tension roller 13 for applying a constant pressure to the conveyance belt 9. The transfer / conveyance belt 9 has a configuration in which it can be brought into contact with / separated from each image carrier 1 by swinging about the drive roller 12 as a rotation center. The transfer material is conveyed by driving the transfer conveyance belt 9 at the same traveling speed as the carrier 1, and the toner image formed on each image carrier 1 by the transfer unit 5 provided opposite to each image carrier 1. Is transferred to a transfer material. At the time of non-image formation, the transfer conveyance belt 9 which is a belt-shaped traveling body is separated from the image carrier 1 and the image carrier 1
Is protected.

(Cleaning Device) As shown in FIG. 1, the cleaning device 14 has a casing 15 having an opening on the side of the conveyor belt 9, and a cleaning blade 16 made of urethane rubber or the like is provided in the opening by a support member 16a. Attached. The cleaning device 14 is mounted on a support frame of the transfer conveyance belt 9, and the cleaning blade 16 has an edge on one side in contact with a position facing the driving roller 12 via the transfer conveyance belt 9. When the residual toner on 9 reaches the edge, it is scraped off. The scraped toner is dropped into the casing 15, and is discharged from the cleaning device 14 by a screw (not shown) as a conveying means for discharging the residual toner. With this configuration, the inside of the casing 15 is not clogged with the residual toner due to the residual toner.

Here, as shown in FIG. 2, the setting conditions for contacting the cleaning blade 16 with the transfer conveyance belt 9 include a contact pressure F, a contact angle θ, a free length L, a plate thickness t of the cleaning blade 16. Is mentioned. Here, in order to stabilize the contact pressure F of the cleaning blade 16 against the transfer conveyance belt 9, a spring pressurizing method is used. In the present embodiment, the contact pressure F of the cleaning blade 16 is 9.
8N (1000 gf), the contact angle θ was 30 °, the free length L was 10 mm, and the plate thickness t was 2 mm.

Cleaning blade used in this embodiment
16 is made of polyurethane rubber, and the property value is JI
When actually measured according to the test method of the vulcanized rubber of S, the A hardness was 73 ° and the rebound resilience was 50%.

As described above, the support frame of the transfer / transport belt 9 has a swingable operating mechanism capable of coming into contact with / separating from the image carrier 1. The driving mechanism for driving is provided independently of the support frame of the transfer and conveyance belt 9. Therefore, in the present configuration, if the transfer conveyance belt 9 is fixed at the time of swinging, the relative position between the transfer conveyance belt 9 and the cleaning blade 16 is shifted. In order to obtain good cleaning performance at the time of image formation, it is desired that the transfer conveyance belt 9 which is the surface to be cleaned moves stably with respect to the cleaning blade 16.

In consideration of the relative positional relationship with respect to the cleaning blade 16, the driving of the transfer / conveying belt 9 is performed when the transfer / conveying belt 9 is swung.
The speed control shown in FIG. 4 was performed so that the relative speed of the transfer conveyance belt 9 with respect to 16 was constant. That is, FIG.
As shown in FIG. 3A, the speed of the drive roller 12 of the transfer / transport belt 9 is increased while the transfer / transport belt 9 is being lifted (FIG. 3A).
(See FIG. 3B), or by lowering by the swing rotation speed during lift-down (see FIG. 3B). The relative speed of the transfer conveyance belt 9 to the blade 16 can be made constant as shown in FIG.

As a result, no belt-like cleaning failure in the thrust direction, which slips through the cleaning blade 16 when the transfer / conveyor belt 9 is started, occurred, and a good cleaning state was obtained. As a result, it is possible to prevent an image defect due to the cleaning defect.

Further, it is more preferable to control the speed of the transfer conveyance belt 9 to be constant in consideration of the start-up time or stop time of the drive motor of the transfer conveyance belt 9 and the operation start-up time during the swing driving. .

The result of the present embodiment is such that a similar result can be obtained in a cleaning mechanism using a blade for a similar belt-like traveling body. For example, an image carrier is used for a transfer material supplied to a secondary transfer unit. A similar result can be obtained in an image forming apparatus using a belt-like intermediate transfer body that carries a toner image on the image carrier in an overlapping manner in order to transfer the upper image. Can be

[Comparative Example 1] In Comparative Example 1, as shown in FIG. 5, when the support frame of the transfer / conveyance belt 9 swings, the speed control that does not drive (the driving roller of) the transfer / conveyance belt 9 is performed. It is a configuration example in the case of using. Except for this configuration, the configuration is the same as that of the above-described first embodiment.

In this configuration, the transfer belt 9 in the direction opposite to the driving direction caused by the operation of the support frame of the transfer belt 9 that holds the cleaning device while the transfer belt 9 is stationary is subsequently moved. When a belt-like cleaning failure in the thrust direction occurs on the activated transfer / transport belt 9 and the transfer / transport belt 9 rotates and the transfer material is attracted to that position, the transfer / transport belt 9 fails to clean the transfer material. The transfer of the toner causes a problem that the transfer material is stained on the back.

Incidentally, in the case where the support frame of the transfer / conveying belt 9 is continuously driven without operating to form an image,
The above-described cleaning failure does not occur in the second and subsequent rotations of the transfer conveyance belt 9.

Comparative Example 2 In Comparative Example 2, as shown in FIG. 6, the transfer / conveyance belt 9 is started before the support frame of the transfer / conveyance belt 9 is lifted up, and the lift-down after the image formation is completed. This is an example of a configuration in which a sequence in which the transfer conveying belt 9 stops later and the driving speed of the driving roller is constant while the transfer conveying belt 9 is being driven is used. Except for this configuration, the configuration is the same as that of the above-described first embodiment.

In this configuration, the relative speed between the cleaning blade 16 and the transfer conveyance belt 9 caused by the swing of the support frame of the transfer conveyance belt 9 that holds the cleaning device when the transfer conveyance belt 9 starts and stops. Due to unevenness, the contact of the cleaning blade 16 becomes unstable,
If a belt-shaped cleaning failure occurs in the thrust direction and the transfer material is attracted to that position, the toner with poor cleaning moves from the transfer conveyance belt 9 to the transfer material, causing a problem that the transfer material is stained on the back.

By the way, in the case of forming an image by continuously driving the support frame of the transfer / conveying belt 9 without operating,
The above-described cleaning failure does not occur in the second and subsequent rotations of the transfer conveyance belt 9.

[Second Embodiment] In the present embodiment, in addition to the structure described in the first embodiment, the transfer / conveyance belt 9 (the driving roller thereof) as a belt-like traveling body is not driven during non-image formation. Then, the transfer frame is moved so that the contact position of the cleaning blade 16 is located earlier than the transfer material suction position at the time of the next image formation. 9 is configured to perform idle rotation.

With this configuration, the transfer / transport belt 9 can be reciprocated with respect to the cleaning blade 16 without driving the transfer / transport belt 9 as a belt-like traveling body. The driving load caused by the distortion of the cleaning blade 16 accumulated by the driving of No. 9 was reduced, and the turning of the cleaning blade 16 did not occur over a long period of use. Further, since the distortion to the cleaning blade 16 gradually accumulates and it is not necessary to frequently perform the present embodiment, the distortion is not affected on the pre-image forming rotation time, for example, when the power supply is on standby. .

[Other Embodiments] In the above-described embodiment,
As the belt-shaped traveling body, a transfer conveyance belt that transfers a toner image formed on an image carrier to the transfer material while transporting the transfer material has been exemplified. However, the present invention is not limited thereto. In order to transfer the toner image formed on the image carrier to the transfer material, the same effect can be expected even if the intermediate transfer member temporarily carries the image formed on the image carrier.

In the above-described embodiment, a copying machine is exemplified as an image forming apparatus. However, the present invention is not limited to this. For example, other image forming apparatuses such as a scanner, a printer, and a facsimile apparatus may be used. The same effects can be obtained by applying the present invention to the image forming apparatus.

[0042]

As described above, according to the present invention,
A cleaning device attached to a support frame of the seamless belt-like traveling body, the cleaning device including a cleaning blade for rubbing the belt-like traveling body and removing toner adhered to the surface thereof; An image forming apparatus in which a support frame of the belt-shaped traveling body abuts on a facing position of any one of rollers holding the traveling body and is capable of swinging about a roller facing the cleaning blade; Even when swinging during driving of the running body, the speed of the running body is controlled by controlling the speed of the running body so that the relative speed of the running body to the cleaning blade is constant. It is possible to prevent defective cleaning, and it is possible to prevent image defects caused by the defective cleaning.

Further, by fixing only the belt-like traveling body during non-image formation and swinging the support frame of the belt-like traveling body, distortion accumulated on the cleaning blade can be eliminated, and good results can be obtained for a long time. Cleaning performance can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an image forming apparatus according to the present invention.

FIG. 2 is a side sectional view of the cleaning device according to the present invention.

FIG. 3 is a schematic diagram illustrating the swinging of a transfer conveyance belt.

FIG. 4 is an explanatory diagram of speed control of the conveyor belt according to the first embodiment.

FIG. 5 is an explanatory diagram of speed control of a conveyor belt in Comparative Example 1.

FIG. 6 is an explanatory diagram of speed control of a conveyor belt in Comparative Example 2.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Image carrier 2 ... Charging means 3 ... Developing means 4 ... Image carrier cleaning means 5 ... Transfer means 6 ... Cassette 7 ... Feeding roller 8 ... Registration roller pair 9 ... Transfer conveyer belt 11 ... Fixing means 12 ... Drive roller 13 ... tension roller 14 ... cleaning device 15 ... casing 16 ... cleaning blade 16a ... support member

Claims (5)

[Claims] A cleaning device attached to a support frame of the seamless belt-shaped traveling body, the cleaning device including a cleaning blade for rubbing against the belt-shaped traveling body to remove toner adhered to the surface thereof; An image forming apparatus in which the cleaning blade is in contact with any one of the rollers that hold the belt-shaped traveling body and the support frame of the belt-shaped traveling body can swing around the roller facing the cleaning blade. In the above, the speed of the belt-shaped traveling body is controlled so that the relative speed of the belt-shaped traveling body with respect to the cleaning blade is constant even during swinging during driving of the belt-shaped traveling body. Image forming device. 2. The speed of a driving roller for rotationally driving the belt-like traveling body is increased by the swing rotation speed during the lift-up of the belt-like travel body, and by the swing rotation speed during the lift-down. The image forming apparatus according to claim 1, wherein the image forming apparatus is slowed down by only one second. 3. The image forming apparatus according to claim 1, wherein the belt-shaped traveling body is fixed during non-image formation, and an operation of swinging the support frame of the belt-shaped traveling body is performed. apparatus. 4. The transfer belt according to claim 1, wherein the belt-shaped traveling body is a transfer conveyance belt that transfers a toner image formed on an image carrier to the transfer material while conveying the transfer material.
The image forming apparatus according to claim 3. 5. The image forming apparatus according to claim 1, wherein the belt-shaped traveling body is an intermediate transfer body that temporarily carries the image formed on the image carrier in order to transfer a toner image formed on the image carrier to a transfer material. The image forming apparatus according to claim 1, wherein: