JP3469360B2 - Image forming device - Google Patents

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 such as a copying machine, a printer and a facsimile machine which uses an electrophotographic system.

[0002]

2. Description of the Related Art In an image forming apparatus such as a copying machine, a printer or a facsimile machine using an electrophotographic system, a photosensitive drum such as a photosensitive drum or a photosensitive belt is rotated during image formation so as to be uniformly charged by a charging device. After that, the exposure device performs image exposure to form an electrostatic latent image, and the electrostatic latent image is developed by a developing device to form a toner image, and the toner image is transferred to a sheet such as transfer paper by the transfer device. Then, the toner is fixed by the fixing device, and after the toner image is transferred, the cleaning device cleans the residual toner on the photosensitive member.

As the transfer means, an endless transfer means composed of a corona charger or a transfer belt is used. The transfer belt is rotated by a driving unit including a gear and the like, and a predetermined bias is applied to the transfer belt so that the sheet is electrostatically held and conveyed, and the sheet is conveyed between the photoconductor and the transfer belt. The toner image on the photoreceptor is transferred to the sheet as it passes.

Since the base layer of the transfer belt is made of rubber, if the transfer belt is constantly brought into contact with the photosensitive member, the compounding material such as oil or wax contained in the rubber may be exposed due to environmental conditions. There is a problem that it moves to the body and the image is abnormal. Therefore, the transfer belt is brought into contact with the photoconductor only during the image forming operation, and the transfer belt is separated from the photoconductor at other times.

In an image forming apparatus using a transfer belt, extra toner hardly adheres to the transfer belt, but since the sheet has an irregular size, the size of the toner image on the photoconductor and the size of the sheet are large. The toners are transferred from the photoconductor to the transfer belt when the values do not match or when a sheet jam occurs. In addition, when the transfer belt and the photoconductor directly contact each other between the sheets and a small amount of toner adheres to the surface of the photoconductor (background stain toner),
Toner is transferred to the transfer belt. As described above, when the toner is transferred to the transfer belt, there is a problem that the backside of the sheet is stained.

In the transfer belt system as well, it is necessary to remove the toner adhering to the transfer belt as with the photoconductor. Therefore, a technique of bringing a cleaning blade into contact with the transfer belt in the counter direction to remove the toner on the transfer belt has been introduced in Japanese Patent Laid-Open No. 34882/1990.

[0007]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
In the above-mentioned technique introduced in the publication, the cleaning blade is brought into contact with the transfer belt in the counter direction to remove the toner on the transfer belt, and therefore, there is an advantage that the cleaning property for the transfer belt is excellent. However, on the other hand, in a high temperature and high humidity environment, the temperature and humidity of the cleaning blade and the belt coating layer increase, which increases the friction coefficient of the cleaning blade and the toner on the background as a lubricant supplied from the photoconductor between the sheets. The cleaning blade may be turned over due to an increase in the friction coefficient between the transfer belt and the cleaning blade due to the decrease in the number, and a narrowing of the cleaning angle due to a decrease in the Young's modulus of the cleaning blade due to an increase in temperature.

As described above, the cleaning means must be provided to remove the excess toner adhering to the transfer belt. However, in the case of the counter type cleaning means, the frictional force between the transfer belt and the cleaning blade is reduced. In order to lower the amount, a small amount of toner that plays the role of a lubricant must be constantly supplied.

In a conventional apparatus that controls the transfer belt to contact the photoconductor only during the image forming operation and separates the transfer belt from the photoconductor at other times, the transfer belt is used in the following three cases. It becomes a state separated from.

1. When toner is forcibly replenished after toner end This is because in a two-component development type developing device, the toner concentration in the developer consisting of carrier and toner decreases with toner consumption, and after toner end Is an operation of forcibly carrying out toner until a desired toner concentration is obtained at the time of replacement.

2. At the time of initial setting of the developer, the toner density control in the developing device is controlled by the T sensor output (T
The sensor is a sensor for measuring the magnetic permeability of the developer, and the toner concentration is measured by utilizing the fact that the observed value of the magnetic permeability changes depending on the toner concentration). The developer initial setting is to ensure that the T sensor output voltage of the initial agent (the toner density of the developer at the time of factory shipment is adjusted to 2.5%) has a certain voltage value (reference voltage value). The sensitivity adjustment work is performed in step 1), and the work is performed by stirring the developer in the developing device to eliminate the bias of the developer in the device.

3. During pre-rotation of the fixing roller This should contribute to the fusion of toner on the transfer paper when the fixing heater is turned on immediately after the power is turned on and the image is output when the temperature distribution of the pressure roller is still uneven. In order to prevent cold offset due to a part of heat energy being taken by the temperature rise of the pressure roller, the fixing roller and the pressure roller are preliminarily rotated so that the temperature distribution becomes saturated. Say.

If the operations in these three cases are performed in a high temperature and high humidity environment, the blades are turned over as described above, the transfer belt cannot be sufficiently cleaned, and the backside of the transfer paper is soiled. Not only that, but in some cases, the transfer belt may break.

Therefore, the driving means for the transfer belt is driven by a driving means different from that for the photoconductor, or the shaft of the driving roller for driving the transfer belt is connected to the main motor via a clutch to transfer the transfer belt. It is conceivable to prevent the transfer belt from rotating in synchronization with the time when the transfer belt separates from the photoconductor. However, this method has a problem that a driving means or a clutch is added, the number of parts is increased, the apparatus is complicated, and the cost is increased.

Therefore, an object of the present invention is to prevent the cleaning blade from being turned up and the transfer paper from being smeared on the back side.
An object is to provide an image forming apparatus that can obtain a good image at low cost.

[0016]

The invention according to claim 1 is
An image carrier, a latent image forming unit that forms a latent image on the image carrier, a developing unit that visualizes the latent image, and a transfer material on which the visible image is transferred are carried and conveyed. Endless transfer means,
A cleaning unit arranged in a counter direction with respect to the moving direction of the endless transfer unit for cleaning the surface of the endless transfer unit, and a contacting / separating unit for relatively contacting and separating the image carrier and the endless transfer unit. In the image forming apparatus having the following, when the endless transfer means is in a moving state, the image carrier and the endless transfer means are always brought into contact with each other by the contacting / separating means , and the developing means is a two-component developing system. so
Yes, at the time of initial setting of the developer,
It is characterized in that it is brought into contact with the carrier .

According to a second aspect of the invention, there is provided an image carrier and the image carrier.
A latent image forming means for forming a latent image on the image carrier, and the latent image
Developing means for forming a visible image and a transfer material to which the visible image is transferred
Endless transfer means for carrying and conveying paper, and the endless transfer means
The endless shape is arranged in the counter direction with respect to the moving direction of
Cleaning means for cleaning the surface of the transfer means
And the image carrier and the endless transfer means are relatively contacted with each other.
In the image forming apparatus having a contacting / separating unit for separating
When the endless transfer means is in a moving state, the contact / separation means
Always contact the image carrier with the endless transfer means.
So, the developing unit employs a two-component developing method, and toner
-Equipped with end detection means, toner after toner end detection
The endless transfer means is brought into contact with the image carrier during forced replenishment .

According to a third aspect of the invention , an image carrier and the image carrier are provided.
A latent image forming means for forming a latent image on the image carrier, and the latent image
Developing means for forming a visible image and a transfer material to which the visible image is transferred
Endless transfer means for carrying and conveying paper, and the endless transfer means
The endless shape is arranged in the counter direction with respect to the moving direction of
Cleaning means for cleaning the surface of the transfer means
And the image carrier and the endless transfer means are relatively contacted with each other.
In the image forming apparatus having a contacting / separating unit for separating
When the endless transfer means is in a moving state, the contact / separation means
Always contact the image carrier with the endless transfer means.
After the power is turned on, there is a fixing pre-rotation mode.
The endless transfer means is brought into contact with the image carrier in the rotation mode .

According to a fourth aspect of the invention, an image carrier, a latent image forming means for forming a latent image on the image carrier, a developing means for visualizing the latent image, and the visible image. An endless transfer means for carrying and carrying a transfer material to be transferred, a cleaning means arranged in a counter direction with respect to the moving direction of the endless transfer means for cleaning the surface of the endless transfer means, and the image carrier. In the image forming apparatus having a contacting / separating means for relatively contacting and separating the endless transfer means and the endless transfer means, when the endless transfer means is in a moving state, the contacting / separating means causes the image carrier and the endless transfer means to move. When the endless transfer means is rotated except when the image is formed by always contacting the endless transfer means
The developing means bias is turned on in a certain cycle.
By turning on and off the toner on the endless transfer means
It is characterized by supplying .

According to a fifth aspect of the present invention, an image carrier, a latent image forming means for forming a latent image on the image carrier, a developing means for visualizing the latent image, and the visible image. An endless transfer means for carrying and carrying a transfer material to be transferred, a cleaning means arranged in a counter direction with respect to the moving direction of the endless transfer means for cleaning the surface of the endless transfer means, and the image carrier. In the image forming apparatus having a contacting / separating means for relatively contacting and separating the endless transfer means and the endless transfer means, when the endless transfer means is in a moving state, the contacting / separating means causes the image carrier and the endless transfer means to move. When the endless transfer means is rotated except when the image is formed, the charging means, the developing means, and the endless transfer means are constantly contacted .
The bias is turned on, <br/> on at a constant cycle in the exposure means, off line on said endless transfer means by
It is characterized by creating an image .

[0021]

[0022]

[0023]

[0024]

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, reference numeral 11 represents a photoconductor as an image carrier, and reference numeral 15 represents an endless transfer means.

Around the photoconductor 11, a charge eliminating lamp 13 for erasing the electric charge remaining on the photoconductor 11 and setting the surface potential thereof to a reference potential of 0 V to -30 V, and the surface of the photoconductor 11 are
Charging charger 12a that uniformly charges around 850V
And a writing unit 4 for forming an electrostatic latent image on the photoconductor 11.
0a, a developing unit 14a that attaches toner to the electrostatic latent image to form a visible image, and the photoreceptor 1 on which the visible image is formed.
Charger 1 for recharging the surface of 1 to -850V
2b, a writing unit 40b that forms an electrostatic latent image on the photoconductor 11, a developing unit 14b that visualizes the electrostatic latent image with toner of a color different from the developer of the developing unit 14a, and Transferring the visible image formed by the means 14a and the developing means 14b onto the transfer paper P, transferring the transfer paper P, and removing the toner remaining on the photoconductor 11 after the transfer to remove the toner. And a cleaner 16 having a blade 17 for cleaning 11.

Digital recording image information (black image information) is sent from a device (not shown) to the line driver circuit of the writing unit 40a and is amplified by the laser driver circuit. This digital recorded image information is a multi-valued signal of 8 bits per pixel, and the laser driver circuit activates the laser diode to emit light in accordance with the digital recorded image information from the line driver circuit.

The laser light emitted from the laser diode is polarized by an optical polarizer composed of a polygon mirror,
The light passes through the f-θ lens, is reflected by the first mirror, the second mirror, and the third mirror 41, is image-formed on the photoconductor 11, and the black image component is exposed. Here, in the photoconductor 11, the potential of the portion (image portion) irradiated with the laser beam 42 is around −100 V, and an electrostatic latent image corresponding to a black original image is formed. Here, the charging charger 12a and the writing unit 40a form a latent image forming means.

Next, the electrostatic latent image corresponding to the black image on the photoconductor 11 becomes a black toner image with toner attached by the developing means 14a. During the developing operation, the developing means 14a drives the developing rollers 70, 71, the stirring roller 72, and the stirring paddle 73 by the driving means, and stirs the developer in the developing device 74 with the stirring roller 72 and the stirring paddle 73 to convey the developer. .

The developing roller 70 adsorbs the developer conveyed from the stirring paddle 73 by a magnet arranged inside and conveys it. A portion of the developer on the developing roller 70 is scraped off by the blade 75, adjusted to a predetermined amount, passes between the photoconductor 11 and the developing rollers 70, 71, and returns to the inside of the developing device 74. The toner is again stirred by the stirring roller 72 and the stirring paddle 73 and then conveyed. Meanwhile blade 7
The developer scraped off by 5 drops into the developing device 74 through the separator 76, and the stirring roller 72 and the stirring paddle 73.
Is again stirred and conveyed.

The developer passes between the photoconductor 11 and the developing rollers 70, 71 while circulating, and develops the electrostatic latent image on the photoconductor 11. Toner is replenished to the developer of the developing device 74 from the toner replenishing section 77. A bias voltage of about −550 V is applied from the power source to the developing rollers 70 and 71, and toner is attached to the image portion on the photoconductor 11 by the developing means 14a, but the non-image portion on the photoconductor 11 is −.
It remains at 850 V, and the toner does not adhere even during development by the developing means 14a.

Next, the control of the toner density will be described.
The initial toner concentration of the developer is set to 2.5%, and the output adjustment of the T sensor 31 is adjusted so that the output value of the toner concentration sensor 31 (hereinafter referred to as T sensor) in this state is 2.5V. (Developer initial setting) is performed. As shown in FIG. 2, the output voltage of the T sensor 31 decreases as the toner concentration in the developing device 74 increases. Therefore,
The toner concentration Vt is controlled by measuring the output voltage of the T sensor 31.

The control reference value Vref of the toner density Vt is
It is changed according to the value obtained from the image density read by the P sensor 78. The control reference value Vref in this example is changed once for every 200 copies.

The P sensor 78 is a reflection type photodiode, which reflects a predetermined amount of light on a non-image portion on the photoconductor 11 and an image pattern formed on the photoconductor 11 to receive light. The image density on the photoconductor 11 is detected by detecting the amount of reflected light returning to the element. For example, when the image density on the photoconductor 11 is low, the toner density value of the T sensor 31 is increased (control reference value Vref).
Set to low). As described above, the T sensor 31 and the P sensor 78 are combined to control the toner density such that the image density is always constant.

Next, the photoconductor 11 has a charging charger 12
The charging process by b, the exposure process by the writing unit 40b, and the developing process by the developing means 14b are performed. These steps are performed only when the two-color mode or the mono-color (red / blue) mode is selected on the operation unit. In the case of the single color mode, the charger 12b and the writing unit 40
b, the developing means 14b does not operate, and the black toner image on the photoconductor 11 advances to the transfer position as it is.

In the two-color mode and the mono-color mode, the photoconductor 11 is charged by the charging charger 12b, and the surface potential thereof becomes about -850V again. When the photoconductor 11 passes a position facing the writing unit 40b, the digital recording information of a color other than black, for example, red / blue, of the original sent from a device (not shown) is output from the writing unit 40b including the LED array. Light emission is activated by the digitized signal.

The photosensitive member 11 has a surface potential of -1 at the portion (image portion) irradiated with the LED light from the writing unit 40b.
00V, and an electrostatic latent image corresponding to the red / blue original image components is formed. Here, the charging charger 12b and the writing unit 40b constitute a latent image forming means.

Next, the electrostatic latent image corresponding to the red / blue image on the photoconductor 11 becomes a red / blue color toner image with toner (red / blue) attached by the developing means 14b. Developing means 14b
Drives the agitating rollers 79, 80, the scooping roller 81, and the developing roller 82 by the driving means during the developing operation.
The developer in the developing device 83 is agitated, circulated, and conveyed.
The developing roller 82 supplies the developer conveyed from the scooping roller 81 to the photoconductor 11 to develop the electrostatic latent image on the photoconductor 11 into a red / blue toner image.

The developing roller 82 is supplied with -750V from the power source.
Front and back bias voltages are applied. Toner is attached to the image portion on the photoconductor 11 by the development by the developing means 14b,
Toner does not adhere to the non-image portion on the photoconductor 11 even by the development by the developing means 14b.

After passing through the developing means 14b, the photoreceptor 11 transfers the toner image onto the transfer paper P from the paper feeding device by the transfer means 15 including the transfer belt 22.
In this case, the transfer paper P is fed from the paper feeding device to the registration roller pair 3
4a, 34b, and the registration roller pair 34a, 3
4b sends the transfer paper P at a timing such that the front end of the toner image on the photoconductor 11 and the front end of the transfer paper P coincide with each other.

The transfer means 15 includes a transfer belt 22, a driving roller 23 for stretching the transfer belt 22, and a driven roller 24.
And a bias roller 27 and a cleaning means 84. The drive roller 23 is connected to the main motor via a gear. The transfer belt 22 rotates with the rotation of the main motor, and the contact / separation unit 60 causes the photosensitive member 1 to rotate.
1 is abutted. Further, the transfer belt 22 is separated from the photoconductor 11 by the contacting / separating means 60 immediately after the main motor stops rotating after the job.

As shown in FIGS. 3 and 4, the contacting / separating means 60 fixes the contact plate 61 on the lower surface of the frame on which the transfer belt 22 is stretched, and the contact plate 61 at its free end. Contacting / separating arm 62 and a contacting / separating lever 63 whose one end is supported by a shaft 62a provided at the base end of the contacting / separating arm 62.
And the cam 6 arranged in contact with the other end of the contact / separation lever 63.
4 and a half rotation clutch 65 fixed to the shaft 64a of the cam 64.

A cushioning material 63a is provided at a portion of the contact / separation lever 63 that comes into contact with the cam 64.

The contact / separation lever 63 uses the stay (not shown) attached to the shaft 62a thereof to move the pressing arm 62,
Since it is configured to be pressed down from the upper part and regulates the urging force from the lower surface of the pressure arm 62 by the compression spring 66, it is interlocked with the vertical movement of the cam 64 of the contact / separation lever 63. The pressure arm 62 also moves up and down about the shaft 62a so that the transfer belt 22 can be brought into and out of contact with the photoconductor 11.

During image formation, the half-rotation clutch 65 is turned on as the main motor rotates, the drive of the main motor is transmitted to the shaft 64a through the gear, the cam 64 rotates, and the extension force of the compression spring 66 is released. Then, the pressure arm 62 moves upward about the shaft 62a to move the transfer belt 2
2 contacts the photoconductor 11. At this time, the width of the nip portion N between the transfer belt 22 and the photoconductor 11 is set to 12 mm.

In the image forming apparatus according to the present embodiment, the main motor is rotated at the time of initial setting of the developer, the forced toner supply mode, the pre-rotation of the fixing roller and the pressure roller, etc., other than the image formation. In this case, the transfer belt 22 rotates as the main motor rotates. When the transfer belt 22 rotates, the control unit 1 controls the operation of the contact / separation unit 60 to bring the transfer belt 22 into contact with the photoconductor 11 as described above.

When the transfer paper P is sent from the registration rollers 34a and 34b to the transfer means 15, a transfer bias having a polarity opposite to the charging polarity of the black toner / color toner is applied from the high voltage power supply 29 to the bias roller 27, and the photoconductor The toner image on 11 is transferred to the transfer paper P at the nip portion N.

When a transfer bias is applied to the transfer belt 22, induced charges are generated in the coating layer on the surface thereof, and the transfer paper P is electrostatically adsorbed and conveyed. After the toner image on the photoconductor 11 is transferred, the transfer paper P is electrostatically separated from the photoconductor 11. Here, even when the transfer paper P is not separated from the photoconductor 11, it is separated from the photoconductor 11 by the separation claw 57 and is conveyed by the transfer belt 22.

The transfer paper P is conveyed by the transfer belt 22, and is separated from the transfer belt 22 by the drive roller 23 by the extreme separation utilizing the strength of the transfer paper P, passes through the guide plate 85, and is fixed to the fixing roller. The toner image on the transfer paper P is fused and fixed by being heated and pressed by the fixing means 50 composed of 51 and the pressure roller 52, and is discharged to the outside as a copy. In this example, after the fixing roller 51 is heated to a predetermined temperature at the same time when the power of the image forming apparatus is turned on, both rollers are pre-rotated for the purpose of preventing the fixing failure caused by the surface temperature unsaturation of the pressure roller 52. There is.

The transfer belt 22 is the cleaning brush 8
6. The residual toner is scraped off by the cleaning means 84 including the cleaning blade 47 and the like. The cleaning blade 47 is arranged in contact with the rotation direction of the transfer belt 22 in the counter direction. The toner remaining on the photoconductor 11 is completely removed by the blade 17 of the cleaner 16 and the brush 87, and the process proceeds to the next image forming step again.

In this example, when the main motor rotates regardless of whether or not an image is being formed, the half-rotation clutch 65 is always turned on to bring the transfer belt 22 into contact with the photoconductor 11 and A small amount of toner (background stain toner) on 11 is supplied to the transfer belt 22 to reduce the friction coefficient between the transfer belt 22 and the cleaning blade 47. The half-rotation clutch 65 is not limited to the half-rotation clutch 65 and may be a solenoid.

Further, in this embodiment, the semi-conductive rubber is used as the transfer belt 22, but the transfer belt 22 is made of a resin material such as PET instead of selecting rubber as the belt material. You may. further,
By omitting the contacting / separating means 60, the transfer belt 22 is always provided on the photoreceptor 1.
The configuration may be such that it contacts with 1.

The control means 1 is for other than the time of image formation,
When the transfer belt 22 rotates and is in contact with the photoconductor 11, the bias of the developing means 14a is applied, or the charging charger 12a, the developing means 14a, and the transfer means 15 are operated to move the writing unit 40a at a predetermined cycle. It is turned on / off to form a line image on the photoconductor 11, and the line image is transferred to the transfer belt 22 to supply toner to reduce the friction coefficient with the cleaning blade 47.

Although the image forming apparatus shown in this embodiment is a digital copying machine, it also has a printer function and can be used as an output device of a personal computer. When the print button of the personal computer is turned on, until the image information is transferred to the memory section (not shown) of the image forming apparatus (during image data processing), or the transferred image information has the capacity of the memory section. If it exceeds, the transfer belt 22 also rotates with the rotation of the main motor until the image information is transferred again after the image information is printed out. Again, as mentioned above,
The transfer belt 22 is brought into contact with the photoconductor 11, and the residual toner (ground stain toner) on the photoconductor 11 is supplied to the transfer belt 22, and the toner reduces the coefficient of friction between the transfer belt 22 and the blade 47.

In this example, the belt-shaped transfer means is used as the endless transfer means, but a drum-shaped transfer means may be used. In addition, the contacting / separating means is attached to the transfer belt 22 so that
You may make it contact and separate 1. INDUSTRIAL APPLICABILITY The present invention is not limited to a monochrome image forming apparatus, but is also applicable to a color image forming apparatus that, for example, superimposes and develops toner images of a plurality of colors on an image carrier and collectively transfers them to a transfer material carried on an endless transfer means. Is also applicable. The present invention applies not only to the endless transfer means but also to the image carrier of the intermediate transfer type endless transfer means for directly transferring and carrying the toner image formed on the image carrier and then transferring it to the transfer material. It is also applicable to the separating operation. The transfer means may be a transfer charger (not in contact with the endless transfer means) or a transfer brush (contact with the endless transfer means), and the charging means may be a charging roller or a charging brush (contact with the endless transfer means). May be used.

[0055]

According to the inventions of claims 1, 2, and 3 ,
The endless transfer means is brought into contact with the image carrier to transfer the toner onto the endless transfer means, and the friction coefficient between the blade and the endless transfer means can be lowered. It is possible to provide an image forming apparatus which can prevent the occurrence of back stains and can obtain a good image at low cost.

According to the fourth aspect of the present invention, the developing bias is turned off and on to transfer the toner on the image carrier onto the endless transfer means, and the friction coefficient between the blade and the endless transfer means is increased. Since the cleaning blade can be lowered, it is possible to more effectively prevent the cleaning blade from being turned over and the transfer paper from being smeared on the back side, and it is possible to provide an image forming apparatus that can obtain a good image at a low cost.

According to the fifth aspect of the invention, when the endless transfer means is rotated except during image formation, the charging means, the developing means and the transfer means are turned on, and the exposure means is turned off at a predetermined cycle. Turn on to form a line image on the endless transfer means,
Since the coefficient of friction between the blade and the endless transfer means can be lowered, it is possible to more effectively prevent the cleaning blade from being turned over and the backside of the transfer paper from being generated, and an excellent image can be formed at low cost. A device can be provided.

[0058]

[Brief description of drawings]

FIG. 1 is a schematic diagram of an image forming apparatus showing an embodiment of the present invention.

FIG. 2 is a characteristic diagram showing the relationship between the toner density and the output of the toner density sensor in the first embodiment.

3 is a side view of a partial cross section showing a contacting / separating unit of a transfer belt in the image forming apparatus shown in FIG.

FIG. 4 is a diagram for explaining the operation of the contacting / separating unit.

[Explanation of symbols]

1 control means 11 photoconductor 12a, 12b Charger 13 Static elimination lamp 14a, 14b Developing means 15 Transfer means 16 cleaner 22 Transfer belt 40a, 40b exposure means 50 fixing means 60 Contact and separation means 84 Cleaning means P transfer paper N Nip part

Claims (5)

(57) [Claims] 1. An image carrier, a latent image forming means for forming a latent image on the image carrier, a developing means for visualizing the latent image, and a transfer material to which the visible image is transferred. An endless transfer means for carrying and transporting the endless transfer means, a cleaning means arranged in a counter direction with respect to the moving direction of the endless transfer means for cleaning the surface of the endless transfer means, the image carrier and the endless transfer means. In the image forming apparatus having a contacting / separating means for relatively contacting and separating the image carrier and the endless transfer means, the contacting / separating means constantly contacts the image carrier with the endless transfer means. The image forming apparatus is characterized in that the developing means is a two-component developing system, and the endless transfer means is brought into contact with the image carrier at the time of initial setting of the developer. 2. An image carrier and a latent image formed on the image carrier.
Latent image forming means and developing means for visualizing the latent image
And an endless device that carries and conveys a transfer material onto which the visible image is transferred.
Of the endless transfer means and the moving direction of the endless transfer means.
The endless transfer means, which is placed in the center direction.
Cleaning means for cleaning, the image carrier,
It has a contacting / separating means for relatively contacting and separating the endless transfer means.
In this image forming apparatus, when the endless transfer means is in a moving state,
The image carrier and the endless transfer means are always in contact by the step.
The developing means adopts a two-component developing system, and
It is equipped with an end detection device, and when the toner is forcibly replenished after the toner end is detected, the endless
The transfer means is brought into contact with the image bearing member.
Image forming apparatus. 3. An image carrier, latent image forming means for forming a latent image on the image carrier, developing means for visualizing the latent image, and transfer material to which the visible image is transferred. An endless transfer means for carrying and transporting the endless transfer means, a cleaning means arranged in a counter direction with respect to the moving direction of the endless transfer means for cleaning the surface of the endless transfer means, the image carrier and the endless transfer means. In the image forming apparatus having a contacting / separating means for relatively contacting and separating the image carrier and the endless transfer means, the contacting / separating means constantly contacts the image carrier with the endless transfer means. An image forming apparatus having a fixing pre-rotation mode after the power is turned on, wherein the endless transfer means is brought into contact with the image carrier in the fixing pre-rotation mode. 4. An image carrier, a latent image forming means for forming a latent image on the image carrier, a developing means for visualizing the latent image, and a transfer material to which the visible image is transferred. An endless transfer means for carrying and transporting the endless transfer means, a cleaning means arranged in a counter direction with respect to the moving direction of the endless transfer means for cleaning the surface of the endless transfer means, the image carrier and the endless transfer means. In the image forming apparatus having a contacting / separating means for relatively contacting and separating the image carrier and the endless transfer means, the contacting / separating means constantly contacts the image carrier with the endless transfer means. When the above-mentioned endless transfer means is rotated other than during image formation,
Turn on the bias of the developing means in a certain cycle.
By turning on and off the toner on the endless transfer means
An image forming apparatus characterized by supplying the . 5. An image carrier, latent image forming means for forming a latent image on the image carrier, developing means for visualizing the latent image, and transfer material to which the visible image is transferred. An endless transfer means for carrying and transporting the endless transfer means, a cleaning means arranged in a counter direction with respect to the moving direction of the endless transfer means for cleaning the surface of the endless transfer means, the image carrier and the endless transfer means. In the image forming apparatus having a contacting / separating means for relatively contacting and separating the image carrier and the endless transfer means, the contacting / separating means constantly contacts the image carrier with the endless transfer means. When the endless transfer means is rotated except during image formation, the charging means, the developing means, and the endless transfer means are rotated.
Was turned on bias, OH <br/> down at a constant cycle in the exposure means, the line on the endless transfer means by turning off
An image forming apparatus characterized by imaging an image.