JPH1115292A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a cleaning blade in an image forming device provided with a belt running body and a cleaning blade from being curled due to the increase in frictional resistance blade, and to eliminate problems such as cleaning failure and damage to the belt. SOLUTION: In this image forming device provided with the endless belt running body 17a and the cleaning blade 17e which slides against the belt running body 17a to clear away toner sticking to its surface, a means which forms toner-supply lines on the belt running body 17a is provided for preventing curling of the cleaning blade 17e, and the toner supply lines are made to differ in amount of toner supply in the direction of the width of the belt running body 17a. Thus, the amount of toner which is inputted to the blade can be controlled in the direction of the width of the belt running body 17a, wasteful consumption of toner is reduced, and the cleaning blade 17e is prevented from curing due to the using up of the toner.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic image forming apparatus such as a copying machine, a facsimile, and a printer, and more particularly, to a belt running member and a blade-shaped cleaning member for cleaning toner adhered to the belt running member. The present invention relates to an image forming apparatus having a configuration including a (cleaning blade).

[0002]

2. Description of the Related Art In an electrophotographic image forming apparatus such as a copying machine, a facsimile, a printer, etc., after a photosensitive member is charged, an original image is directly exposed by an exposure device, or a laser scanning optical system or an LED optical writing device is used. Optical writing is performed in accordance with an image signal by a built-in optical system or the like, an electrostatic latent image is formed on the photoreceptor, and the latent image is developed with a toner of a developing device to be visualized. The image is transferred to a transfer material such as transfer paper or film via an intermediate transfer member. Then, the transfer material after the transfer is conveyed to a fixing device, and the toner image is fixed on the transfer material by the fixing device to obtain an image.

In such an image forming apparatus, as a belt running body to which toner adheres, for example, there is a photosensitive belt or an intermediate transfer belt as an image carrier, and the belt adheres to the surface of the photosensitive belt or the intermediate transfer belt. A cleaning blade is known as one of the cleaning members for cleaning the toner.

A transfer belt of a transfer and transfer device is known as a belt traveling body to which toner adheres. The transfer belt of this transfer / conveyance device is an endless belt running body made of an elastic member such as a rubber-based material. The transfer belt is stretched over a plurality of rollers such as a driving roller and a driven roller, and is supported by an image carrier (photoconductor, intermediate member). The transfer belt holding the transfer material is placed in contact with the image carrier at the time of transfer, and the transfer material is sandwiched and conveyed at the nip portion between the image carrier and the transfer belt, and is disposed on the back side of the transfer belt. The toner image on the image carrier is transferred to the transfer material by applying a high voltage to the bias applying means (bias applying roller, bias applying brush, etc.), and the transferred transfer material is separated from the image carrier and transferred to the fixing unit. It is designed to be transported toward. Further, in order to remove the toner remaining on the transfer belt surface after the transfer material is separated,
A cleaning blade is provided.

[0005]

In a copying machine equipped with a belt-like image carrier (photosensitive belt or intermediate transfer belt) or a transfer belt such as a transfer belt, a large number of copies having a small image area may be taken. Or, if a large number of blank copies are taken, there will be no residual toner on the belt running body, and there will be no toner on the edge of the cleaning blade in contact with the belt running body. For this reason, the friction coefficient μ between the belt running body and the cleaning blade is increased, the rubbing resistance is increased, the edge of the cleaning blade is caught on the belt surface, and the edge of the cleaning blade may be turned up. If the blade is turned over, it causes cleaning failure, causes image stains, back stains on the transfer material, and toner scattering, and also causes damage to the belt traveling body. This problem also occurs in a belt-shaped image carrier (photosensitive belt or intermediate transfer belt). In particular, in the case of a transfer belt, the toner adhered to the cleaning blade is smaller than that of an image carrier that directly carries a toner image. Since the amount is small, the above problem is likely to occur.

Therefore, as means for solving the above problem,
In the case of a belt-shaped image carrier, a toner supply line is formed between the papers of the image carrier to supply toner to the edge portion of the cleaning blade, and in the case of a transfer belt, between the papers of the image carrier. There is a method of forming a toner supply line, transferring this line to a transfer belt, and supplying toner to the edge of the cleaning blade, thereby increasing the coefficient of friction between the belt running member and the cleaning blade due to toner shortage. It is conceivable to prevent the cleaning blade from being turned up by preventing the rubbing resistance from increasing.

Here, when the belt running body is a transfer belt, the toner supply line is formed, for example, once for a plurality of copies, and the image between the sheets of an image carrier such as a photoconductor is printed. The data is written over the entire width and transferred to the transfer belt. The more frequently the toner supply line is inserted, the harder the blade is turned up. However, on the other hand, wasteful toner may be consumed, or toner may be supplied excessively, and cleaning may not be completed, resulting in defective cleaning. Also, if the background toner adheres to the belt and is input to the tip of the blade in a large amount, the toner supply line for preventing the turn-up becomes unnecessary, but the background contamination amount is greatly related to the humidity, and there is almost no humidity at 90% humidity. Down to Therefore, considering that the toner supply line is used at high humidity, a toner supply line for preventing the curl is indispensable.

[0008] Therefore, there is a method of setting blade conditions such that the contact pressure of the cleaning blade against the transfer belt is set high, for example, such that the toner supply line for preventing the curl is reliably cleaned. At the time of normal cleaning, the cleaning property becomes excessive, and the side effect of deterioration of the blade occurs early.

In a cleaning device for a belt-shaped photoreceptor, as a method for improving the cleaning performance in a state where the contact pressure of the cleaning blade is relatively low, a cleaning blade is moved in a direction perpendicular to the driving direction of the belt-shaped photoreceptor. There is known a method in which the pressure contact is made so as to have an inclination angle with respect to the angle (Japanese Patent Application Laid-Open No. 60-107686). A method has also been proposed in which a linear cleaning blade is brought into contact with a cylindrical photoreceptor at an inclined angle to improve the cleaning performance (Japanese Utility Model Laid-Open No. 3-45572, Japanese Utility Model Laid-Open No. 3-47574).
issue).

In these methods, the cleaning blade is made to contact the photoreceptor at an inclined angle so that a large amount of toner is not input to the cleaning blade at the same time in the entire width so that a cleaning failure does not occur. If this method is adopted for a belt traveling body cleaning device, it is possible to remove toner under normal cleaning conditions even when the toner supply line is formed, but if the cleaning blade has an inclination angle, In addition, a large installation space for the cleaning blade is required, and the cleaning blade must be installed on a portion of the belt traveling body where the surface to be cleaned is flat. That is, since the belt surface of the roller portion supporting the belt running body is a curved surface having an arc shape, when the blade is brought into contact with the curved surface portion at an inclined angle, the blade pressure is not uniformly applied (to the both ends of the blade). The more the contact pressure becomes weaker), it becomes impossible to obtain uniform blade conditions in the width direction, and this causes a cleaning failure. Therefore, it is not preferable to install the cleaning blade with an inclination angle because the installation space becomes large, the installation position is restricted, and depending on the installation position, cleaning failure may occur.

The present invention has been made in view of the above circumstances, and in an image forming apparatus having a belt running body and a cleaning blade for cleaning toner adhered to the belt running body, the present invention relates to an image forming apparatus comprising: A means for supplying toner is provided to prevent the occurrence of curling due to an increase in the sliding resistance of the cleaning blade for cleaning the belt running body, to solve problems such as poor cleaning and damage to the belt running body, and to perform normal cleaning. It is an object of the present invention to enable the toner on the belt to be satisfactorily removed with a relatively low contact pressure. Further, the present invention clarifies the distribution of the amount of toner supplied by the means for supplying the toner to the belt traveling body, and furthermore, the belt traveling along the toner supply line under various machine use conditions (humidity, number of sheets used, etc.). It is an object of the present invention to minimize wasteful consumption of toner when forming the toner on the body and to perform control without turning up the blade. Further, it is an object of the present invention to show an apparatus configuration particularly requiring a toner supply unit, and to provide a toner supply unit to a belt traveling body.

[0012]

In order to achieve the above object, an invention according to claim 1 comprises an endless belt running body,
An image forming apparatus having a cleaning blade for rubbing the belt running body and cleaning toner adhered to the surface of the belt running body, further comprising a unit for supplying toner to the belt running body to prevent the cleaning blade from being turned up. The amount of toner supplied by the toner supply means differs in the width direction of the belt traveling body.
Here, the belt traveling body according to the present invention is a belt-shaped image carrier or a belt-shaped transfer material carrier. As a toner supply unit, a toner supply line is formed in the width direction of the belt traveling body, and the amount of toner supplied by the toner supply line is made different in the width direction of the belt traveling body.

That is, in the image forming apparatus according to the present invention, there is provided means for supplying toner to the belt traveling body (image carrier or transfer material carrier), and a toner supply line is formed in the width direction of the belt traveling body. As a result, toner is supplied to the edge portion of the cleaning blade, so that the friction coefficient between the belt running body and the cleaning blade due to the lack of toner is prevented from increasing, and the occurrence of turning of the cleaning blade is prevented. Since the amount of toner supplied by the toner supply line differs in the width direction of the belt traveling body, the amount of toner input to the cleaning blade can be controlled in the width direction of the belt traveling body.

Means for supplying toner to the belt traveling body for preventing the cleaning blade from turning up is, in particular, an endless belt for carrying and transferring the transfer material and transferring the toner image formed on the image carrier to the transfer material. It is effective for running objects. Therefore, the invention according to claim 3 provides an image carrier on which a toner image is formed, and an endless belt traveling body that carries and conveys a transfer material and transfers the toner image formed on the image carrier to the transfer material. And an image forming apparatus provided with a cleaning blade for rubbing the belt running body and cleaning toner adhered to the surface of the belt running body, wherein a means for supplying toner to the belt running body to prevent the cleaning blade from being turned up Wherein the amount of toner supplied by the toner supply means differs in the width direction of the belt traveling body. As a toner supply means, a toner supply line is formed in the width direction of the belt traveling body, and the amount of toner supplied by the toner supply line is made different in the width direction of the belt traveling body.

More specifically, an image carrier on which a toner image is formed, a belt traveling body disposed opposite to the image carrier, and the belt traveling body Bias applying means disposed on the back side of the belt, and a cleaning blade for cleaning the surface of the belt traveling body,
The belt running body holding the transfer material is brought into contact with the rotating image carrier, and the toner image on the image carrier is transferred to the transfer material by applying a high voltage to the bias applying means, and the transferred transfer material is fixed. In the image forming apparatus provided with a transfer conveyance device configured to convey the toner toward the image forming section and to remove the toner remaining on the surface of the belt traveling body after the transfer material is separated, by using the cleaning blade. Means for forming a toner supply line between the papers of the image carrier, and transferring the line to the belt traveling body. The amount of toner supplied by the toner supply line is determined by the width of the belt traveling body. Be different in direction.

That is, in the image forming apparatus according to the present invention, a toner supply line is formed between the papers of the image carrier,
Means for transferring the line to a belt traveling body of a transfer / transporting device, which is a transfer material carrier, and forming a toner supply line in a width direction of the belt traveling body, so that toner is supplied to an edge portion of the cleaning blade. As a result, it is possible to prevent the friction coefficient between the belt running body and the cleaning blade from increasing due to running out of toner, thereby preventing the cleaning blade from being turned up. Since the amount of toner supplied by the toner supply line differs in the width direction of the belt traveling body, the amount of toner input to the cleaning blade can be controlled in the width direction of the belt traveling body.

Here, in the image forming apparatus, the belt traveling body of the transfer / conveyance device is an endless, medium-resistance transfer belt. More specifically, the belt transport of the transfer transport device is an endless, medium-resistance transfer belt stretched over a plurality of rollers and arranged to face the image carrier. There is a contact / separation mechanism for contacting / separating the carrier (claim 7). By providing the transfer belt contact / separation mechanism, when the image carrier is a belt-shaped photoconductor or an intermediate transfer belt, the toner supply line is moved to the belt-shaped image carrier by the contact / separation of the transfer belt. It is possible to easily switch between supply to the cleaning blade and transfer to the transfer belt, and even in an image forming apparatus configured to combine both the belt-shaped image carrier and the transfer belt, cleaning of both belt traveling bodies is performed. It is possible to prevent the blade from being turned up.

In the image forming apparatus according to the present invention, the toner supply line is formed in a range larger than a maximum sheet passing width and smaller than a cleaning blade width in a width direction of the belt traveling body. . The amount of toner supplied by the toner supply line is different between the center and both ends of the belt traveling body. Specifically, the amount of toner supplied by the toner supply line is small at the center of the belt running body and large at both ends.
0).

That is, if toner is input to the entire width of the cleaning blade, there is a risk of toner scattering or cleaning failure. Therefore, the toner supply line is formed in a range smaller than the cleaning blade width. However, if the amount of toner supplied by the toner supply line is the same at both the center and both ends of the belt running body, the toner does not spread to both ends of the blade, and the toner may run out at both ends of the blade due to toner shortage. Also, the toner supply amount at the center may be excessive. Therefore, as described above, the amount of toner supplied to the cleaning blade can be controlled by increasing the amount of toner supplied by the toner supply line at the central portion of the belt traveling body and increasing the amount at both ends. It is possible to prevent the consumption of toner and the occurrence of curling at both ends of the blade.

Here, as a means for increasing the amount of toner supplied by the toner supply line at the central portion of the belt running body and increasing it at both ends, the toner supply line is formed to be thin at the center and thick at both ends. (Claim 11) Alternatively, the density at the center portion is made lower and the density at both ends is made higher (Claim 12), or the number of lines at both ends is increased more than at the center portion (Claim 13). is there.

Incidentally, the state of toner adhesion to the image carrier and the transfer belt changes depending on the use conditions (humidity, the number of sheets used, the drive torque of the belt running body, etc.) of various machines of the image forming apparatus. Therefore, according to a fourteenth aspect of the present invention, in the image forming apparatus according to any one of the fourth to thirteenth aspects, a hygrometer is provided around the image carrier, and the toner supply is performed in accordance with the humidity detected by the hygrometer. The amount of toner supplied by the line is controlled.

According to a fifteenth aspect of the present invention, in the image forming apparatus according to any one of the fourth to thirteenth aspects, the amount of toner supplied by the toner supply line is controlled in accordance with the number of images to be formed.

According to a sixteenth aspect of the present invention, in the image forming apparatus according to any one of the fourth to thirteenth aspects, the amount of toner supplied by the toner supply line is controlled in accordance with the driving roller torque of the belt traveling member.

According to the present invention, as a means for forming a toner supply line, in the image forming apparatus according to any one of claims 4 to 16, a latent image is formed on an image carrier in accordance with image data. An optical writing device for forming an image, and a storage unit for image data, wherein the pattern of the toner supply line is stored in advance in the storage unit for the image data, and the pattern is stored in the image when the toner supply line is formed. Using the data as data, a latent image of a toner supply line is formed between the papers of the image carrier by the optical writing device, and the latent image is developed with toner of a developing unit. It is possible to form a toner supply line of a desired pattern having a different supply amount in the width direction of the belt traveling body on the belt traveling body.

In the above-mentioned image forming apparatus, the optical writing device performs optical writing by scanning a laser beam (claim 18) or the optical writing device using an LED array (claim 18). There is Claim 19).

Further, as another means for forming a toner supply line, in the invention according to claim 20, claims 4 to 1 are provided.
6. The image forming apparatus according to claim 6, further comprising an exposure device that exposes the document image to the image carrier, and for forming a toner supply line in a non-image area of a document placing table on which the document is placed. A pattern is provided, and when forming a toner supply line, the pattern is exposed between the papers of the image carrier by the exposure device to form a latent image of the toner supply line, and the latent image is developed with toner of a developing unit. Accordingly, it is possible to form a toner supply line having a desired pattern in which the toner supply amount differs in the width direction of the belt traveling body on the belt traveling body.

[0027]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail based on illustrated embodiments.

FIG. 1 is an overall configuration diagram showing an example of the configuration of an image forming apparatus according to the present invention. The image forming apparatus shown in FIG. 1 is an example of a digital copying machine that can also be used as a printer, and includes an image forming unit (printer) 1 for forming an image by an electrophotographic process, and a document reading unit (scanner) 2 for reading a document image. An automatic document feeder (ADF) 3 for automatically feeding a document, a paper feed unit 4 having a plurality of feed trays 4a to 4d for feeding transfer sheets of various sizes, Double-sided tray 5 for temporarily storing and refeeding paper, and copy / print discharge unit (sorter) 6
And so on.

The automatic document feeder (ADF) 3 is installed on the contact glass 2a of the document reading unit 2 so as to be able to open and close with the rear end side as a fulcrum. The original placed on the original table 3a is contacted with the contact glass 2 by a transport belt 3b via a feed roller.
After the document is read by the document reading unit 2 and the document image is read by the document reading unit 2, the document is discharged to the paper discharge unit 3c. Further, the automatic document feeder 3 is opened, and the document is manually inserted into the contact glass 2.
It can also be set on a.

An original reading unit (scanner) 2 illuminates the original on the contact glass 2a with a light source 2b, a reading unit 2f including an image sensor for reading the original image, and guides the original image to the reading unit 2f. It comprises an optical system composed of mirror groups 2c, 2d, 2e and an imaging lens 2f,
The light source 2b and the mirror group scan the original surface while moving,
The reading section 2f sequentially reads the original image, converts it into an image signal, and transmits it to an image processing section (not shown). Since the copying machine having the configuration shown in FIG. 1 includes a developing device for one color such as red and blue in addition to a developing device for black, a color image is stored on the image sensor of the reading unit 2f. A color CCD or the like that can be read by color separation is used, and is converted into an image signal corresponding to each color by an image processing unit.

The image forming section (printer) 1 includes a drum-shaped photosensitive member 10 serving as an image carrier, a first charging device 11, a first optical writing device 7, and a first developing device disposed around the photosensitive member. 1
2, a second charging device, a second optical writing device 14, a second developing device 15, a registration roller 16, a transfer transport device 17, a cleaning device 18, and the like, and further downstream of the transfer transport device 17 in the transfer paper transport direction. A fixing device 19 is provided.

The first charging device 11, the first optical writing device 7, and the first developing device 12 are for forming a black image, and the first optical writing device 7 includes a laser diode 9a and a light such as a rotating polygon mirror. A laser diode 9a emits light in response to a black image signal from an image processing unit (not shown), and includes a deflector 8, a scanning imaging lens 9b such as an fθ lens, and a mirror 9c. Charged photoreceptor 10
A latent image of a black image is written thereon, and the latent image of the black image is the first latent image.
The image is developed with the black toner of the developing device 12. The second charging device, the second optical writing device 14, and the second developing device 15 are for forming a color image of one color such as red or blue.
Charges the photoreceptor 10 after the black image is formed, and the second optical writing device 14 is composed of an LED array and a lens array, and corresponds to a color image signal such as red or blue from an image processing unit (not shown). The array emits light, and a latent image of a color image such as red or blue is written on the photoreceptor 10, and the latent image of the color image is developed by the second developing device 15 with a color toner such as red or blue.

The black and color toner images formed on the photoreceptor 10 are fed from one of the plurality of paper feed trays 4a to 4d of the paper feed unit 4 or the manual feed table 4f, and are passed through registration rollers 16. The image is transferred onto the transfer paper conveyed to the nip portion between the transfer belt 17a of the transfer conveyance device 17 and the photoconductor 10. Then, the transfer paper after the image transfer is a photoconductor 10
The toner image is fixed to the transfer paper by the heating roller 19a and the pressure roller 19b of the fixing device 19. The transfer paper after fixing is transferred to the discharge tray 6a or the multi-stage discharge tray 6b of the discharge section 6 via the discharge rollers 20 and 21 during one-sided copying.
The paper is conveyed to the tray 5 for both sides via the both-side conveyance path 22 at the time of duplex copying. Further, the toner remaining on the photoreceptor 10 after the transfer of the toner image is removed by the cleaning device 18 and the charge is removed by a charge removing device (not shown). The residual toner collected by the cleaning device 18 is sent to a waste toner tank 24 by a transport mechanism (not shown).

Although the configuration example of the image forming apparatus according to the present invention has been briefly described above, the image forming apparatus to which the present invention is applied is not limited to the illustrated configuration, but includes a belt-shaped photosensitive member or an intermediate transfer belt. If the image forming apparatus is provided with a belt traveling body and a cleaning blade for cleaning the same, such as an image forming apparatus having a cleaning blade for cleaning the toner adhered to the belt-shaped image carrier, the original image is directly transferred to the photosensitive member. An analog type copier for exposure or a configuration with only a printer may be used.A mono-color image forming apparatus with only one optical writing device and developing device, or a full-color image forming with multiple developing devices is possible. A simple image forming apparatus may be used.

Next, as a specific embodiment of the present invention, the configuration and operation of the transfer / transport device will be described in detail. FIG.
FIG. 2 is a front view illustrating a schematic configuration of a transfer and transfer device. In FIG. 2, the transfer conveyance device 17 includes an endless, medium-resistance transfer belt 17a disposed opposite to the photoconductor 10, a driving roller 17b and a driven roller 17c supporting the transfer belt 17a, and a transfer belt 17a. A bias applying roller 17d disposed on the back side for applying a transfer bias; and a cleaning blade 17e for cleaning the surface of the transfer belt 17a.
(17g, 17)
h) and a release mechanism of the transfer / conveyance unit (release lever 17)
f).

When the release lever 17f is tilted in the direction of the arrow in the drawing, the transfer / transport unit release mechanism is rotated clockwise about the drive roller 17b to be released. This mechanism is provided to make it easy to remove jammed paper in the event of a jam and to ensure the detachability of the transfer / transport unit and the photosensitive drum unit during maintenance.

FIG. 3 is an explanatory view of a transfer belt contact / separation mechanism. The transfer belt 17a contact / separation mechanism is constituted by an electromagnetic spring clutch 17g with a cam, a contact / separation lever 17h, a contact / separation arm 17i, a spring 17j and the like. It is configured. The contact / separation arm 17i is fixed to the shaft of the contact / separation lever 17h, and a pressing spring 17j is inserted between the lower end of the contact / separation arm 17i and the base of the transfer / transport unit. The upper end of the contact / separation arm 17i contacts the support 17k of the transfer belt 17a to support the transfer belt.

FIG. 3A shows a state in which the contact / separation lever 17h is pressed down by the cam of the electromagnetic spring clutch 17g against the pressing force of the spring 17j, and the transfer belt 17a is separated from the photosensitive member 10. It will be in the state that was done. When the image forming operation is not performed, the transfer belt 17a is
2A, the image forming operation is started, and the transfer paper S sent to the registration roller 16 is aligned with the leading edge of the image on the photoconductor 10 by the registration roller. When the leading end of the transfer paper S comes close to the contact portion between the photoconductor 10 and the transfer belt 17a, the electromagnetic spring clutch 17g is turned on.
As shown in FIG. 3B, the contact / separation lever 17h moves upward, and the contact / separation arm 17i moves upward due to the pressing force of the spring 17j.
Push up k. As a result, the transfer belt 17a comes into contact with the photoconductor 10 to form a nip portion W, and the toner image is transferred to the transfer paper S at the nip portion. After the end of the transfer, the electromagnetic spring clutch 17g is turned off, the cam returns to the state shown in FIG. 3A, and the contact / separation lever 17h is pushed downward to lower the contact / separation arm 17i, whereby the transfer belt 17a is moved. It is separated from the photoconductor 17a.

The transfer belt contact / separation mechanism is used to prevent substances and oil components in the material of the transfer belt from adhering to the photoreceptor due to prolonged contact, and to reduce the pattern density on the photoreceptor by a P sensor. It is provided to prevent the toner image from being transferred to the transfer belt when detecting. Also,
When the photosensitive member is configured to use a belt-like photosensitive member or a structure including an intermediate transfer belt, and it is necessary to input a toner supply line for preventing blade turn-up described below to a cleaning blade of the belt-like image bearing member. Is
It is necessary to separate the transfer belt from the image carrier, and the transfer belt contact / separation mechanism effectively functions.

Next, the basic configuration and operation of the transfer / transport apparatus will be described with reference to FIGS. FIG. 4 is an explanatory diagram of the configuration and operation of the transfer / transport device including the electrical system.
2A shows a state in which the transfer belt 17a is separated from the photoconductor 10, and FIG. 2B shows a state in which the transfer belt 17a is in contact with the photoconductor 10. FIG. 5 is a cross-sectional view of the transfer belt,
FIG. 6 is an explanatory diagram of a transfer step by the transfer / conveyance device.

The transfer belt 17a, which is an endless, medium-resistance belt running body, has a two-tank structure as shown in FIG. 5, for example. When the electric resistance measured according to JIS K6911 is 100 V DC, Surface layer 17
0a indicates that the surface resistivity of the belt surface is 1 × 10 ⁹ Ω to 1 × 1
0 ¹² Ω, the surface resistivity of the inner layer 170 b is 1 × 10 ⁷ Ω or more.
1 × 10 ⁹ Ω and its volume resistivity is 5 × 10 ⁸ Ω
・ Cm to 5 × 10 ¹⁰ Ω · cm.

In FIG. 4, a bias applying roller 17d for applying a transfer bias is provided downstream of the driven roller 17c in the moving direction of the transfer belt 17a and in contact with the back side of the transfer belt 17a. ,
A contact electrode is provided to apply a charge having a polarity opposite to the charge polarity of the toner on the photoconductor 10 to the transfer belt 17a, and is connected to a high-voltage power supply 25. Incidentally, a bias applying brush, a bias applying blade, or the like may be used instead of the bias applying roller 17d.

Driving roller 17b and driven roller 17c
Is for detecting a current flowing on the transfer belt 17a as a feedback current, and the current supplied from the bias applying roller 17d is controlled by detecting this current.
For this reason, a transfer control plate 26 for setting the supply current to the bias applying roller 17d according to the detection current is connected to each of the rollers 17b and 17c. It is connected.

In such a transfer and transfer device 17,
As the transfer paper S is fed out from the registration rollers 16, the transfer belt 17a is moved by the contact / separation mechanism shown in FIG.
Is set so that the support 17k contacts the transfer belt 17a with the photoreceptor 10, and the position of the transfer belt 17a changes from the separated state of FIG. 4A to the contact state of FIG.
A nip portion W having a width (for example, about 12 mm) that allows the transfer paper S to be conveyed while being in contact with the photoconductor 10 is formed at a position facing the photoconductor 10. On the other hand, the photoreceptor 10
The surface is charged to, for example, -800 V, and as shown in FIG. 6, the toner moves to the nip portion while positively charged toner is electrostatically attracted to the surface.

In the nip portion W shown in FIG. 4B, the toner on the photoreceptor 10 is transferred to the transfer paper S by the transfer bias from the bias applying roller 17d located on the back side of the transfer belt 17a as shown in FIG. Transfer to the top. The transfer bias is applied from the high voltage power supply 12 in the range of -1.5 kV to -6.5 kV. The transfer bias is variably set as a result of the constant current control as described below. That is, FIG. 4 (A), the (B), the time of the current value output from the high voltage power supply 12 and I _1, detects a feedback current flowing through the ground side through the transfer belt 17a the rollers 17b, from 17c If the value was I _2, between these _{two, I 1 -I 2 = I OUT} ( However, I _OUT: constant) controlling the value of I ₁ so that the relation is obtained. this is,
Temperature, regardless of variations occurring in the production quality of the environmental conditions change or transfer belt 17a such as humidity, is done to eliminate the change in the transfer efficiency by stabilizing the surface potential V _P on the transfer sheet S .

[0046] That is, the transfer belt 17a and the transfer paper by Mitateru the current flowing into the photosensitive member 10 side as I _OUT through S, the transfer belt 17a due to low resistance or high resistance of the surface resistance V _P on the transfer sheet S This prevents a change in the ease of current flow to the transfer paper S from affecting the separation performance and transfer performance. In the case of this embodiment, I _OUT is conveying speed 330 mm / sec, the effective bias applying roller length 310mm, I _OUT = -35μ
Good transfer was obtained when A ± 5 μA was set.

When the image is transferred from the photoconductor 10, the transfer paper S is also charged at the same time. Therefore,
Due to the relationship between the true charge of the transfer belt 17a and the polarization charge generated on the transfer paper S side, the transfer paper S can be electrostatically attracted onto the transfer belt 17a to separate the transfer paper from the photoreceptor 10. Then, the transfer paper S using the curvature separation of the photoconductor 10
The separation operation of the transfer paper S is promoted by the peeling operation based on the strength of its own waist.

However, in such electrostatic attraction, when the humidity is high due to a change in environmental conditions, the current easily flows through the transfer sheet S, so that the transfer sheet cannot be separated properly.
Therefore, the surface layer 17 of the transfer belt 17a shown in FIG.
0a, the transfer of the true charge to the transfer paper S at the nip W is delayed because the resistance value is set slightly higher, and the bias applying roller 17d is further moved in the transfer paper transport direction than the nip W. At the downstream side. This allows
The transfer of the true charges from the transfer belt 17a to the transfer sheet S is delayed so as to avoid an electrostatic attraction relationship between the transfer sheet S and the photoconductor 10.

To delay the transfer of the true charge used in this case means that no charge is generated on the transfer sheet S upstream from the transfer sheet S to the nip portion on the photosensitive member 19 side. This prevents the transfer sheet S from being wound around the photoconductor 10, and also prevents separation failure of the transfer sheet S from the photoconductor 10.

Further, it is better to select a transfer belt 17a having a small resistance change due to an environmental change.
As a conductive material for controlling resistance, carbon, zinc oxide and the like are added in an appropriate amount, and when a rubber belt is used as the elastic belt, chloroprene rubber, EPDM rubber, silicone rubber, epichlorohydrin rubber, etc. have a low hygroscopic property, It is desired to select a material having a stable resistance value.

The current I _OUT flowing to the photoconductor 10 side
Is not unique and can be reduced when the transport speed is low, and increased when the transport speed is high.

On the other hand, the transfer paper S passing through the nip W is
The toner is conveyed electrostatically in accordance with the movement of the transfer belt 17a,
Curvature separation is performed by the roller 17b on the driving side. For this reason, the diameter of the drive roller 17b is set to 18 mm or less. Furthermore, in the case of using such a drive roller 17b is fine 45K paper (stiffness: horizontal 21 [cm ^3/100]) experimental result that separation is possible of is obtained.

The transfer belt 17 is driven by the driving roller 17b.
The transfer paper S separated from the heat roller 19a and the pressure roller 1 that constitute the fixing device 19 are guided by a guide plate.
7b. In the fixing device 19, the toner on the transfer paper S is melted by heating and pressed against the transfer paper S to fix the toner on the transfer paper S.

The transfer belt 17a on which the transfer of the image to the transfer paper S and the separation have been completed, the support 17k is lowered by the contact / separation mechanism shown in FIG. Then, the belt surface is cleaned by the cleaning unit 23. The cleaning unit 23 includes a cleaning blade 17e. By rubbing the transfer belt 17a, toner transferred from the surface of the photoreceptor 10 or scattered around the transfer belt 17a without being transferred is attached. In this case, the toner and paper dust of the transfer paper S are scraped off.

The transfer belt 17a rubbed by the cleaning blade 17e has a low friction coefficient to prevent a phenomenon such as an increase in driving force due to an increase in rubbing resistance or a turn-up of the cleaning blade 17a. -Based resin material, for example, polyvinylidene fluoride, ethylene tetrafluoride and the like. The toner or paper dust scraped off from the surface of the transfer belt 17a is conveyed and stored in the waste toner tank 24 of the image forming apparatus main body shown in FIG. 1 by the collecting screw 23a.

The basic configuration and operation of the transfer / transport device have been described above. However, in an image forming apparatus equipped with such a transfer / transport device 17, a large number of copies having a small image area can be taken or a blank copy can be mistakenly taken. When a large number of sheets are taken, there is no residual toner on the transfer belt 17a, and there is no toner on the edge of the cleaning blade 17e in contact with the transfer belt 17a. For this reason,
The friction coefficient μ between the transfer belt 17a and the cleaning blade 17e increases, and the edge of the cleaning blade 17e is caught on the belt surface due to an increase in rubbing resistance.
The edge of the cleaning blade 17e may be turned up. And when blade turning occurs,
Occurrence of cleaning failure and transfer surface back contamination
This may cause toner scattering and damage the transfer belt.

To solve the above problem,
In the present invention, means for supplying toner to the transfer belt 17a is provided to prevent the cleaning blade 17e from being turned up. More specifically, there is provided a means for forming a toner supply line between the sheets of the photoconductor 10 and transferring the line to the transfer belt 17a. That is, a line for supplying toner is formed between the sheets of the photoreceptor 10, and this line is
The toner is supplied to the edge of the cleaning blade 17e after being transferred to the transfer belt 17a.
The coefficient of friction between the cleaning blade 17e and the cleaning blade 17e is prevented from increasing, thereby preventing the cleaning blade 17e from being turned up.

The toner supply line is, for example, as shown in FIG. 7A, a cleaning sheet having a thickness of about 2 mm between papers of the photoreceptor once per a plurality of copies. A line substantially parallel to the contact line of the blade 17e,
Alternatively, a line inclined by an angle θ from the contact line of the cleaning blade 17e as shown in (b) is written over the entire image width and transferred to the transfer belt 17e.

However, since the toner supply line has a larger amount of toner than the residual toner adhered when the toner is transferred to a normal transfer sheet, the toner supply line on the transfer belt 17a is shown in FIG. If the toner supply amount is a straight line parallel to the cleaning blade 17e as shown or a straight line inclined by an angle θ from the contact line of the cleaning blade 17e as shown in FIG. There is a case where toner is excessively supplied at the central portion of the cleaning blade 17e and cleaning cannot be completed. Conversely, toner supply may be insufficient at both ends and one end of the cleaning blade 17e.

As shown in FIG. 8, the effective development width B (the width to which the background stain toner or the like adheres) is usually larger than the maximum paper width A (the maximum image width) of the transfer paper S. Further, the width C of the cleaning blade is generally further increased in order to clean the toner. In the width direction of the transfer belt, the width D of the normal toner supply line for preventing the blade from turning is formed in a range larger than the maximum paper passing width A and smaller than the cleaning blade width C, and is substantially the same as the effective developing width B. It is formed. That is, if toner is input to the entire width of the cleaning blade, there is a risk of toner scattering or cleaning failure. Therefore, the toner supply line is formed in a range smaller than the width of the cleaning blade. Accordingly, the input toner does not basically enter the outside of the effective developing width B, but the toner spreads laterally at the edge of the cleaning blade, and then spreads to the cleaning blade width C. However, when the input toner amount in the effective development width B is small, the toner does not sufficiently spread to the cleaning blade width C, the friction coefficient μ at both ends of the blade increases, the rubbing resistance increases, and blade turning occurs. May be (turned more often than the blade edge). Also, if the input toner amount in the effective development width B is increased to prevent the blade from being turned up at both ends, the toner supply amount at the central portion becomes excessive, causing unnecessary toner consumption and cleaning failure. There is.

Therefore, in the present invention, the toner supply amount by the toner supply line for preventing the turning-up is made different between the center portion and both end portions in the width direction of the transfer belt 17a.
More specifically, the amount of toner supplied by the toner supply line is reduced at the center and increased at both ends. As a result, the amount of toner input to the cleaning blade 17e can be controlled in the belt width direction, and wasteful toner consumption and the occurrence of curling at both ends of the blade can be prevented.

As a specific method of controlling the amount of toner supplied by the toner supply line, for example, as shown in the toner supply line of FIG. 8, the thickness of the line is changed at the center and both ends, and the center is made thin. , Thicken both ends, or change the density of the line between the center and both ends like a toner supply line, reduce the density at the center, and increase the density at both ends, or the toner supply line As described above, there are methods such as increasing the number of lines only at both ends, and by these methods, it is possible to control the amount of toner supplied by the toner supply line so that it is small at the center and large at both ends. Further, as an example in consideration of the control of the amount of toner supplied by the toner supply line and the cleaning performance, a plurality of diagonal lines are formed in the width direction of the transfer belt, like the toner supply line, at both ends. There is a method of increasing the amount of toner (thickening the line) as it goes. In this case, since there is a gap between the hatched lines, the toner is not input to the entire width of the cleaning blade at the same time, so that the cleaning property is improved. Also, there is a method in which the amount of toner on both sides is increased and the center is formed in a wavy shape so that the center can be easily cleaned, as in the toner supply line.
Furthermore, the toner supply line is composed of a plurality of circular points, and the amount of toner by the circular points increases toward both sides (the area (or density) of the circular points increases, as shown in FIG. There is a method. In the case of such a shape, there is a gap between the circular points, but since the toner flows right and left at the tip of the cleaning blade,
The toner is supplied also in the gap between the points, and the effect is sufficiently obtained. Thus, the amount of toner supplied by the toner supply line can be controlled so as to be smaller at the center and larger at both ends, and the cleaning property after toner supply is also improved.

Incidentally, the relationship between the humidity around the photosensitive drum 10 and the background stain on the photosensitive drum has a relationship as shown in FIG. When the photoreceptor drum has a background stain, the background becomes dirty (transferred) on the transfer belt 17a, and the toner becomes the amount of toner input to the cleaning blade 17e. However, when the humidity increases, the background stain amount decreases. When the humidity is high, the amount of toner input to the cleaning blade is extremely reduced, and the cleaning blade is easily turned up.

Therefore, in the present invention, the amount of toner supplied by the toner supply line is controlled according to the humidity around the photosensitive drum 10. That is, a toner supply line is usually inserted for every 30 copies, but is changed every 20 copies when the humidity is 60% or more, and is changed every 40 copies when the humidity is 30% or less. In this manner, the amount of background dirt is reduced by the change in humidity, so that a large amount of toner is replenished in the toner supply line, so that the blade can be prevented from being turned up while consuming a small amount of useless toner.

Next, as the number of copies (the number of images formed) increases, the friction coefficient μ of the belt running body such as the transfer belt increases due to cracks and filming on the surface of the belt.
Tend to rise.

Therefore, in the present invention, the amount of toner supplied by the toner supply line is controlled in accordance with the number of copies used (the number of images formed). More specifically, as shown in FIG. 10, as the number of copies used on the transfer belt increases, the interval at which the toner supply line for preventing the curl is gradually changed. For example, up to 50K sheets (K: thousand units), a toner supply line is provided for every 30 sheets of a copy.
For 0K copies, change every 25 copies, 100K-150
For K copies, change every 20 copies, 150K to 200K
In the case of a single copy, it is changed every 15 copies. In addition, as the number of copies used increases, the amount of toner input to the cleaning blade by the toner supply line for step-up prevention is gradually increased. The increase is performed by controlling the thickness, the density, the number, and the like of the toner supply lines. When the transfer belt is replaced, the transfer belt is reset to return to the initial set value. As described above, by controlling the amount of toner input to the cleaning blade in accordance with the number of copies of the belt, the blade can be prevented from being turned up while consuming a small amount of useless toner.

Next, the turning of the cleaning blade 17e is determined by the friction coefficient μ between the transfer belt 17a and the cleaning blade. The rough tendency is, as described above, that the more the number of copies used (the number of images formed), the more the belt becomes. The coefficient of friction μ tends to increase due to cracks and filming on the surface of the surface, but if you look more closely, the coefficient of friction μ fluctuates somewhat depending on the temperature and humidity and the type of paper used at that time, The belt driving torque fluctuates due to the fluctuation of the friction coefficient μ.

Therefore, in the present invention, as shown in FIG. 11, a torque sensor 30 is provided on the drive shaft of the drive roller 17b of the transfer belt 17a, and the torque sensor 30 is detected every number of copies, and Using a toner supply line for preventing curling according to the value, the cleaning blade 17
This is to control the amount of toner supplied to e. Specifically, as shown in FIG. 12, it is sufficient to form a toner supply line for preventing turning up once every 30 copies up to a torque of 2.5 kgf · cm, and copy up to 2.5 to 3 kgf · cm. 2
Once for every 0 sheets, once for every 15 sheets up to 3-3.5 kgf ・ cm, once for every 10 sheets for 3.5-4 kgf ・ cm, once for every 5 sheets And By controlling the amount of toner supplied to the cleaning blade in accordance with the driving roller torque of the transfer belt in this way, it is possible to prevent the blade from being turned up while consuming a small amount of useless toner.

Next, the means for forming the toner supply line will be described. In an image forming apparatus such as a digital copying machine (or a printer, a facsimile, or the like) shown in FIG. 1 having optical writing devices 7 and 14 for forming image data into a latent image using a laser beam or an LED array,
If the pattern of the toner supply line to as shown in FIG. 8 is provided in advance in the storage area of the image data, the pattern is used as image data when forming the toner supply line, and the optical writing devices 7 and 14 are used. Thus, a latent image on a toner supply line can be easily formed between sheets of the photoconductor. FIG. 13 shows an example of a toner supply line forming unit in an image forming apparatus having an optical writing device using laser light.
2 shows an example of a toner supply line forming unit in an image forming apparatus having an optical writing device using an LED array. FIG. 15 shows a block diagram of a control system.

The optical writing device 7 shown in FIG. 13 deflects a laser beam from a laser diode 9a which is turned on by a control signal from the image processing controller shown in FIG. 9b to scan the photosensitive member 10 and form a latent image on the photosensitive member 10 by a laser beam that is scanned one after another, and stores the latent image in advance outside the image area of the photosensitive member 10 (between sheets) when necessary. A latent image is formed by laser light in accordance with the image data of the toner supply line pattern stored in the area. Then, if this latent image is developed with toner of a developing device (not shown) and directly transferred to a transfer belt (not shown), various toner supply lines as shown in FIG. 8 are formed on the transfer belt. It is formed.

The optical writing device 14 shown in FIG. 14 is turned on by a control signal from the image processing controller shown in FIG.
The light from the ED array is passed through the lens array to the photoconductor 10.
The LED array has a function of forming a latent image by exposing the LED array on the outer side of the image area of the photoconductor 10 (between sheets) when necessary according to the image data of the toner supply line pattern stored in the storage area in advance. Forms a latent image. Then, if this latent image is developed with toner of a developing device (not shown) and directly transferred to a transfer belt (not shown), various toner supply lines as shown in FIG. 8 are formed on the transfer belt. It is formed.

The above example is an example of the toner supply line forming means in the digital image forming apparatus having the configuration shown in FIG. 1. Next, an exposing device for directly exposing the original image to the photosensitive member will be described. An example of a means for forming a toner supply line in an image forming apparatus having the same will be described. In an image forming apparatus that directly exposes a document image to a photoreceptor by an exposure device, a pattern for forming an image forming line for toner supply is printed on a non-image area on a contact glass on which the document is placed. And the like. 16 to 1
8 shows an example of a toner supply line forming means in an image forming apparatus having an exposure device.

In the image forming apparatus shown in FIG. 16, an exposure lamp of an exposure apparatus is turned on by a signal from a sequence controller of a control unit (not shown), and the image formed by a lens is instantaneously laid on a belt-shaped photosensitive member. It has a function of forming an image, and a toner as shown in FIG. 8 is provided at a position where a latent image is formed before or after the image area on the photoreceptor on the exposure surface outside the image area on the contact glass. Supply line ~
The pattern is formed as a latent image before or after the image area on the photoconductor. Then, if this latent image is developed with toner of a developing device (not shown) and transferred to a transfer belt (not shown), a toner supply line is formed on the transfer belt.

The above-described patterns are formed as latent images by the same number as the number of times of exposure of the exposure apparatus. However, the patterns formed as latent images other than when necessary can be erased by the eraser which is the next process. There is also a means for forming the pattern as a latent image when necessary by enlarging or reducing the exposure area.

In the image forming apparatus shown in FIG. 17, the exposure lamp of the exposure apparatus is turned on by a signal from a sequence controller of a control unit (not shown), and the exposure lamp and the first mirror and the second and third mirrors scan the lens. Has a function of forming a latent image on a drum-shaped photoreceptor by the light imaged by, and on the exposure surface outside the image area on the contact glass,
By providing a pattern of lines for toner supply as shown in FIG. 8 at a position where a latent image is formed before or after the image area on the photoreceptor, the pattern is formed before or after the image area on the photoreceptor. The pattern is formed as a latent image. And
If this latent image is developed with toner of a developing device (not shown) and transferred to a transfer belt (not shown), a toner supply line is formed on the transfer belt.

The above-described patterns are formed as latent images by the same number as the number of times of exposure of the exposure apparatus. However, by using the eraser which is the next process, the latent images can be erased except when necessary. Further, means for forming the pattern as a latent image when necessary by shortening the scanning area,
There is also a means for changing the lighting timing of the exposure lamp and exposing the pattern when necessary to form a latent image.

In the image forming apparatus shown in FIG. 18, the exposure lamp of the exposure apparatus is turned on, the contact glass is moved by a signal from a sequence controller of a control unit (not shown),
It has the function of forming a latent image on the belt-shaped photoreceptor by light formed by the lens, and forms a latent image on the contact glass surface outside the image area before or after the image area on the photoreceptor. By providing a pattern of the toner supply lines 1 to 3 as shown in FIG. 8 at the position to be formed, the pattern is formed as a latent image before or after the image area on the photoconductor. Then, if this latent image is developed with toner of a developing device (not shown) and transferred to a transfer belt (not shown),
A toner supply line is formed on the transfer belt.

The above patterns are formed as latent images by the same number as the number of times of movement of the contact glass. However, the patterns formed into latent images other than when necessary can be erased by an eraser which is the next process. There are also means for forming the pattern as a latent image when necessary by shortening the moving distance, and means for forming a latent image by exposing the pattern when necessary by changing the lighting timing of an exposure lamp.

Although the embodiments of the present invention have been described above, the present invention is not limited to a transfer belt of a transfer / conveying apparatus and an apparatus configuration using a cleaning blade thereof, and also a belt-shaped image carrier such as a photosensitive belt or an intermediate transfer belt. The present invention can be similarly applied to an apparatus configuration using a cleaning blade, and by forming a toner supply line according to the present invention as necessary on a belt traveling body such as a photosensitive belt or an intermediate transfer belt, It is possible to effectively prevent the cleaning blade from being turned up while consuming a small amount of useless toner.

[0080]

As described above, claims 1, 2, 4
The image forming apparatus according to (1) includes a unit for supplying toner to a belt traveling body (an image carrier or a transfer material carrier), and forms a toner supply line in a width direction of the belt traveling body. The toner is supplied to the portion, so that the friction coefficient between the belt running body and the cleaning blade due to the lack of toner is prevented from increasing, and the occurrence of turning of the cleaning blade is prevented. Since the amount of toner supplied by the toner supply line differs in the width direction of the belt running body, the amount of toner input to the cleaning blade can be controlled in the width direction of the belt running body.

According to a third aspect of the present invention, there is provided an image forming apparatus comprising: an image carrier on which a toner image is formed; and an endless end for carrying and transferring a transfer material and transferring the toner image formed on the image carrier to the transfer material. An image forming apparatus comprising: a belt-like traveling body; and a cleaning blade that rubs the belt-like traveling body and cleans toner adhered to the surface of the belt-like traveling body. Means for supplying toner, wherein the amount of toner supplied by the toner supply means is different in the width direction of the belt traveling body, and as the toner supply means,
Forming a toner supply line in the width direction of the belt traveling body,
Since the amount of toner supplied by the toner supply line is made different in the width direction of the belt running body, the amount of toner input to the cleaning blade can be controlled in the width direction of the belt running body, and waste toner can be reduced. With little consumption, the friction coefficient between the belt running body and the cleaning blade due to running out of toner is prevented from increasing, and the occurrence of the turning of the cleaning blade is prevented.

In the image forming apparatus according to the fifth aspect, an image carrier on which a toner image is formed, a belt traveling body disposed opposite to the image carrier, and a rear surface side of the belt traveling body are provided. Bias applying means, and a cleaning blade for cleaning the surface of the belt running body, and the belt running body holding the transfer material is brought into contact with the rotating image carrier to apply a high voltage to the bias applying means. The toner image on the image carrier is transferred to a transfer material, the transferred transfer material is conveyed toward a fixing unit, and the toner remaining on the belt traveling body surface after the transfer material is separated is cleaned by the cleaning blade. In an image forming apparatus provided with a transfer / conveyance device, a line for supplying toner is formed between sheets of the image carrier to prevent the cleaning blade of the transfer / conveyance device from being turned up, and the line is moved by the belt running. Means for transferring the toner to the body, and the amount of toner supplied by the toner supply line is made different in the width direction of the belt running body. Therefore, the amount of toner input to the cleaning blade is controlled in the width direction of the belt running body. Thus, the friction coefficient between the belt running body and the cleaning blade due to running out of toner is prevented from increasing, and the cleaning blade is prevented from being turned up.

Further, in the image forming apparatus according to the present invention, since the belt running body of the transfer / conveying device is an endless, medium-resistance transfer belt, the blade is turned up by the toner supply line according to the present invention. The effect of prevention is obtained. Further, in the image forming apparatus according to claim 7,
The belt traveling body of the transfer conveyance device is an endless, medium-resistance transfer belt that is stretched over a plurality of rollers and disposed opposite to the image carrier, and the transfer conveyance device moves the transfer belt to the image carrier. The transfer belt has a contact / separation mechanism for contacting / separating the transfer belt. When the image carrier is a belt-shaped photoconductor or an intermediate transfer belt, the contact / separation mechanism for the transfer belt is provided. With the separation, it is possible to easily switch between supplying the toner supply line to the cleaning blade of the belt-shaped image carrier or transferring the toner to the transfer belt,
Also in an image forming apparatus having a configuration in which both the belt-shaped image carrier and the transfer belt are combined, it is possible to prevent the cleaning blades of both belt traveling bodies from being turned up.

Further, in the image forming apparatus according to the present invention, the toner supply line is formed in the width direction of the belt traveling body in a range larger than the maximum sheet passing width and smaller than the cleaning blade width. And
The amount of toner supplied by the toner supply line is different between the central portion and both ends of the belt running body (claim 9). Specifically, the amount of toner supplied by the toner supplying line is small at the central portion of the belt running body. The amount of toner input to the cleaning blade can be controlled at the center and both ends of the belt traveling body because both ends have a large amount (claim 10). It is possible to effectively prevent the occurrence of turning at both ends of the blade

Further, the means for increasing the amount of toner supplied by the toner supply line at the center portion of the belt running body and increasing the toner supply amount at both end portions is as follows. Both ends are formed thicker, or the density at the center is low and the density at both ends is high, as in claim 12, or the number of lines at both ends is larger than the center as in claim 13. , The amount of toner input to the cleaning blade can be easily controlled at the center and both ends of the belt traveling body.

According to a fourteenth aspect of the present invention, in the image forming apparatus according to any one of the fourth to thirteenth aspects, a hygrometer is provided around the image carrier, and a humidity detected by the hygrometer is used. Since the amount of toner supplied by the toner supply line is controlled accordingly, even in an environment where there is a change in humidity, it is possible to prevent the cleaning blade from being turned up with little consumption of waste toner.

According to a fifteenth aspect of the present invention, in the image forming apparatus according to any one of the fourth to thirteenth aspects,
Since the amount of toner supplied by the toner supply line is controlled in accordance with the number of formed images, the amount of toner input to the cleaning blade is controlled in accordance with the use condition of the belt traveling body, and little waste toner is consumed. The turning of the cleaning blade can be prevented.

According to a sixteenth aspect of the present invention, in the image forming apparatus according to any one of the fourth to thirteenth aspects,
Since the amount of toner supplied by the toner supply line is controlled according to the driving roller torque of the belt traveling member, the amount of toner input to the cleaning blade is controlled according to the driving roller torque of the belt traveling member. The turning of the cleaning blade can be prevented without consumption.

Further, in the image forming apparatus according to the present invention, in the image forming apparatus according to any one of claims 4 to 16, an optical writing apparatus for forming a latent image on an image carrier according to image data. An image writing device that performs optical writing by scanning with a laser beam (claim 18) or optical writing by using an LED array (claim 19); The pattern of the toner supply line is stored in advance in the data storage unit, and when the toner supply line is formed, the pattern is used as image data,
Since the latent image on the toner supply line is formed between the papers of the image carrier by the optical writing device and the latent image is developed with the toner of the developing unit, the toner supply amount is different in the width direction of the belt traveling body. The toner supply line having the above pattern can be easily formed on the belt traveling body.

According to a twentieth aspect of the present invention, in the image forming apparatus according to any one of the fourth to sixteenth aspects,
An exposure device for exposing a document image to an image carrier, a pattern for forming a toner supply line in a non-image area of a document placing table on which a document is placed is provided, and when forming a toner supply line, The pattern is exposed between the papers of the image carrier by the exposure device to form a latent image on a toner supply line, and the latent image is developed with the toner of the developing means. It is possible to easily form a toner supply line having a desired pattern different in the direction on the belt traveling body.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram showing one configuration example of an image forming apparatus according to the present invention.

FIG. 2 is a front view illustrating a schematic configuration of a transfer / conveyance apparatus including a belt traveling body according to the present invention.

FIG. 3 is an explanatory diagram of a transfer belt contact / separation mechanism of the transfer / conveyance device.

FIG. 4 is an explanatory diagram of a configuration and an operation including an electrical system of the transfer and transfer device.

FIG. 5 is a partial cross-sectional view of the transfer belt.

FIG. 6 is an explanatory diagram of a transfer step by the transfer / conveyance device shown in FIG. 4;

FIG. 7 is an explanatory diagram of the embodiment of the present invention, showing an example of a transfer belt on which a toner supply line is formed.

FIG. 8 is an explanatory diagram of the embodiment of the present invention, in which a width of forming a toner supply line with respect to a width of a cleaning blade;
FIG. 4 is an explanatory diagram of a pattern of the toner supply line.

FIG. 9 is a diagram illustrating a relationship between the humidity around the photosensitive drum and the amount of background contamination of the photosensitive drum.

FIG. 10 is an explanatory diagram of the embodiment of the present invention, and is a diagram illustrating a relationship between the number of copies used for the transfer belt and the number of copies for forming a toner supply line for preventing the turning-up.

FIG. 11 is an explanatory view of the embodiment of the present invention, and is a plan view of a transfer belt provided with a torque sensor on a drive shaft of a drive roller.

FIG. 12 is an explanatory diagram of the embodiment of the present invention, and is a diagram illustrating a relationship between a driving roller torque of a transfer belt and the number of copies for forming a toner supply line for preventing a turn-up.

FIG. 13 is a diagram illustrating an example of a toner supply line forming unit, and is a schematic configuration diagram of a main part of an image forming apparatus having an optical writing device using laser light.

FIG. 14 is a diagram illustrating another example of a toner supply line forming unit, and is a schematic diagram illustrating a main configuration of an image forming apparatus having an optical writing device using an LED array.

FIG. 15 is a block diagram of a control system of the image forming apparatus shown in FIG. 13 or FIG.

FIG. 16 is a view showing still another example of the toner supply line forming means, and is a schematic view of a main configuration of an image forming apparatus having an exposure device.

FIG. 17 is a view showing still another example of a toner supply line forming unit, and is a schematic configuration diagram of a principal part of an image forming apparatus having an exposure device.

FIG. 18 is a view showing still another example of the toner supply line forming means, and is a schematic configuration diagram of a principal part of an image forming apparatus having an exposure device.

[Explanation of symbols]

 7 First Optical Writing Device 10 Photoconductor (Image Carrier) 11 First Charging Device 12 First Developing Device 13 Second Charging Device 14 Second Optical Writing Device 15 Second Developing Device 17 Transfer Conveying Device 17a Transfer Belt ( Belt running body) 17b drive roller 17c driven roller 17d bias applying roller (bias applying means) 17e cleaning blade 19 fixing device 23 cleaning unit 25 high voltage power supply 26 transfer control plate 30 torque sensor S transfer paper (transfer material)

Claims (20)

[Claims] 1. An image forming apparatus comprising: an endless belt running body; and a cleaning blade for rubbing the belt running body and cleaning toner adhered to the surface of the belt running body. An image forming apparatus, comprising: means for supplying toner to the belt traveling body, wherein the amount of toner supplied by the toner supplying means varies in the width direction of the belt traveling body. 2. An image forming apparatus according to claim 1, wherein said belt running member is a belt-shaped image carrier or a belt-shaped transfer material carrier. 3. An image carrier on which a toner image is formed, an endless belt traveling body for carrying and conveying a transfer material and transferring the toner image formed on the image carrier to the transfer material, and the belt traveling An image forming apparatus including a cleaning blade that rubs against a body and cleans toner adhered to a surface of a belt traveling body, comprising: a unit that supplies toner to the belt traveling body to prevent the cleaning blade from being turned up; An image forming apparatus, wherein the amount of toner supplied by a supply unit varies in a width direction of a belt traveling body. 4. The image forming apparatus according to claim 1, wherein a toner supply line is formed in a width direction of the belt running member as a toner supply unit, and a toner supply amount of the toner supply line is reduced. An image forming apparatus, which differs in a width direction of a belt traveling body. 5. An image carrier on which a toner image is to be formed, a belt traveling body disposed to face the image carrier, a bias applying means disposed on the back side of the belt traveling body, The cleaning device has a cleaning blade for cleaning the surface of the belt traveling body. The belt traveling body holding the transfer material is brought into contact with the rotating image carrier, and the toner image on the image carrier is formed by applying a high voltage to the bias applying unit. An image forming apparatus including a transfer / transport device configured to transfer to a transfer material, transport the transferred transfer material toward a fixing unit, and clean the toner remaining on the surface of the belt traveling body after the transfer material is separated by the cleaning blade. An apparatus for forming a line for supplying toner between the sheets of the image carrier to prevent the cleaning blade of the transfer / conveyance device from being turned up, and transferring the line to the belt traveling body; An image forming apparatus, wherein a toner supply amount by a toner supply line differs in a width direction of a belt traveling body. 6. The image forming apparatus according to claim 5, wherein the belt running body of the transfer / conveying device is an endless, medium-resistance transfer belt. 7. An image forming apparatus according to claim 5, wherein the belt traveling body of the transfer / conveying device is an endless, medium-resistance transfer belt stretched over a plurality of rollers and arranged to face the image carrier. An image forming apparatus, wherein the transfer / conveying device has a contact / separation mechanism for bringing a transfer belt into and out of contact with an image carrier. 8. The image forming apparatus according to claim 4, wherein the toner supply line is formed in the width direction of the belt traveling body in a range larger than the maximum sheet passing width and smaller than the cleaning blade width. An image forming apparatus comprising: 9. The image forming apparatus according to claim 4, wherein the amount of toner supplied by the toner supply line is different between a center portion and both end portions of the belt running member. . 10. The image forming apparatus according to claim 9, wherein
An image forming apparatus according to claim 1, wherein the amount of toner supplied by the toner supply line is small at the center of the belt running body and large at both ends. 11. The image forming apparatus according to claim 10, wherein the toner supply line is formed to have a narrow center portion and a thick end portion. 12. The image forming apparatus according to claim 10, wherein the toner supply line is formed to have a lower density at the center and a higher density at both ends. 13. The image forming apparatus according to claim 10, wherein the number of toner supply lines at both ends is larger than that at the center. 14. The image forming apparatus according to claim 4, further comprising a hygrometer around the image carrier, wherein the amount of toner supplied by the toner supply line is changed according to the humidity detected by the hygrometer. An image forming apparatus comprising: 15. An image forming apparatus according to claim 4, wherein the amount of toner supplied by the toner supply line is controlled in accordance with the number of images to be formed. 16. An image forming apparatus according to claim 4, wherein an amount of toner supplied by a toner supply line is controlled in accordance with a driving roller torque of the belt running member. . 17. An image forming apparatus according to claim 4, further comprising an optical writing device for forming a latent image on an image carrier in accordance with image data, and a storage unit for the image data. The pattern of the toner supply line is stored in advance in the image data storage means, and when the toner supply line is formed, the pattern is used as image data, and the optical writing device uses the pattern between the papers of the image carrier. An image forming apparatus, comprising: forming a latent image on a toner supply line; and developing the latent image with toner of a developing unit. 18. The image forming apparatus according to claim 17, wherein the optical writing device performs optical writing by scanning a laser beam. 19. The image forming apparatus according to claim 17, wherein the optical writing device performs optical writing using an LED array. 20. An image forming apparatus according to claim 4, further comprising an exposure device for exposing a document image to an image carrier, wherein said exposing device exposes a document image to a non-image area of a document placing table on which a document is placed. A pattern for forming a toner supply line is provided,
When forming the toner supply line, the pattern is exposed between the sheets of the image carrier by the exposure device to form a latent image of the toner supply line, and the latent image is developed with toner of a developing unit. Image forming apparatus.