JP2001305878A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent occurrence of inferior cleaning performance and/or a cleaning blade from being reversed, even if surface friction coefficient of a transfer belt changes. SOLUTION: A image forming device includes the transfer belt 71 holding/ carrying a recording material, an image forming assembly forming a toner image onto the recording material hold by the transfer belt 71, and a cleaning means cleaning the transfer belt 71. The cleaning means includes the cleaning blade 5 pivotally supported with the flexibility of shaking with, attaching to and detaching from the transfer belt 71. The shaking support angle between the cleaning blade 5 and the transfer belt 71 is set in the range of 0 to 15 deg., if the contacting direction toward the transfer belt 71 is defined as positive, in the case the cleaning blade 5 attaches to and detaches from the surface of the transfer belt. In addition, the transfer belt 71 is configured so that the abrasion loss of the transfer belt surface is estimated in the rage of 0.01 to 1.0 μm per 10,000 revolutions in an actual operation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus using an electrophotographic process such as a copying machine, a printer, a facsimile or the like, and more particularly to a cleaning means for a recording material carrier in an image forming apparatus.

[0002]

2. Description of the Related Art In recent years, multifunction peripherals having all output terminals such as copiers, printers, and fax machines have been widely accepted in the market. Although an image forming apparatus using an electrophotographic process has been widely accepted as such a network-compatible output terminal, the so-called Du limit of the number of sheets that the main body can continue to operate normally without maintenance.
tyCycle has been cited as one of the major problems. One of the biggest limiting factors of DutyCycle is the life of the image carrier, and from the viewpoint of ecology, eliminating waste, that is, reducing consumables, extending the life of consumables, and improving reliability Has become a major issue.

[0003] In addition, while digitalization is progressing from the conventional analog device, there is also a problem that the cost of the main body is equivalent to or less than that of the analog device. Further, while the conventional copiers and printers are mainly black-and-white machines, the use of full-color originals or output files in offices is rapidly increasing. Therefore, a monochrome equivalent full-color printer is becoming an issue not only in the analog equivalent digital machine but also in the main body cost and the running cost. Therefore, a technology that can dramatically reduce the TCO (overall required cost as viewed from the user) is desired.

Under these circumstances, in recent years, a plurality of photosensitive drums and a transfer belt for carrying and transporting a recording material have been provided.
A color image forming apparatus for obtaining a color image by sequentially superimposing and transferring toner images of different colors formed on the respective photosensitive drums onto a recording material carried on the transfer belt, that is, a so-called four-tandem type color image formation. Devices are becoming mainstream.

Further, in the above-described image forming apparatus, various kinds of deposits (toner scattered from the photosensitive drum, toner transferred from the photosensitive drum at the time of a jam or a paper interval) are formed on the transfer belt as a recording material carrier. When an image is formed on the second side of the recording material, a release agent oil or the like that has adhered to the recording material when the toner image on the first side is fixed, the counter blade method, the fur brush method, It has been proposed to provide an oil cleaner roller, an oil cleaner web, and the like for removing the release agent oil from the transfer belt. Further, there has been proposed a toner produced by a polymerization method in which such a release agent oil does not need to be used and oil is internally added.

FIG. 6 shows an example of an image forming apparatus for adsorbing and conveying a recording material such as paper on a transfer belt (endless belt) as a recording material carrier and forming an image.
This will be briefly described based on the above.

The image forming apparatus has a photosensitive drum 205 inside, and a toner image is formed on the photosensitive drum 205. A transfer belt 206 as a recording material carrier is installed adjacent to the photosensitive drum 205, and the toner image formed on the photosensitive drum 205 is transferred onto the recording material P carried and conveyed on the transfer belt 206. You. Recording material P on which toner image has been transferred
After the toner image is fixed by heat and pressure in the fixing device 209, the toner image is discharged out of the device as a recorded image.

An exposure lamp 2 is provided around the photosensitive drum 205.
01, photoconductor drum charger 202, exposure device 203, developing device 20
4. A transfer charger 207 and a cleaner 208 are provided, and a light source device and a polygon mirror (not shown) are provided above the apparatus.

The polygon mirror rotates and scans the laser light emitted from the light source device, and the light flux of the scanning light is changed by the reflection mirror, and the photosensitive drum is changed by the fθ lens.
A latent image corresponding to an image signal is formed on the photosensitive drum 205 by condensing and exposing the light on the generatrix of the 205.

The developing device 204 is filled with a predetermined amount of toner by a toner supply device (not shown). The developing device 204 develops the latent image on the photosensitive drum 205 and visualizes it as a toner image.

The recording material P is accommodated in a recording material cassette (not shown), from which a plurality of conveying rollers and registration rollers are provided.
The toner is supplied to the transfer belt 206 via the transfer belt 213, and is sequentially sent to the transfer unit facing the photosensitive drum 205 by the transfer by the transfer belt 206.

The transfer belt 206 is made of a polycarbonate resin sheet, a polyethylene terephthalate resin sheet (PE
T resin) or polyvinylidene fluoride resin sheet, polyurethane resin sheet, a polyamide resin sheet, a polyimide resin sheet dielectric resin sheet by dispersing the resin filler such as carbon black of the insulating resin having a volume resistivity of 10 ^7, such as It is made of a material adjusted to be as low as about 10 ¹⁵ Ωcm, and its both ends are overlapped and joined together to form an endless shape, or a seamless (seamless) belt is used.

When the transfer belt 206 is rotated by the drive roller 211 and reaches a certain speed, the recording material P is sent out from the registration roller 213 to the transfer belt 206, and the recording material P is conveyed toward the transfer portion. At the same time, the image writing signal is turned ON, and an image is formed on the photosensitive drum 205 at a predetermined timing based on the signal. Then, the transfer charger 207 applies an electric field or electric charge in the transfer section below the photosensitive drum 205, so that the toner image formed on the photosensitive drum 205 is transferred to the recording material P. When the recording material P is sent out from the registration roller 213 onto the transfer belt 206,
Immediately with the transfer belt 206 between the attraction charger 214 and the attraction roller opposed roller 215, an electric field or charge is applied by the attraction charger 214 to be electrostatically held on the transfer belt 206 and conveyed.

As the transfer charger 207, a non-contact charger such as a corona discharge or a contact charger using a charging member such as a charging roller, a charging brush or a charging blade is used. The non-contact charger has problems that ozone is generated, and the image is not formed stably because it is vulnerable to environmental changes in the temperature and humidity of the atmosphere because it is charged via air. On the other hand, the contact charger has advantages such as ozonelessness and resistance to temperature and humidity environmental fluctuations.

Next, the recording material P to which the toner image has been transferred is
At the downstream side of the transfer belt 206 in the transport direction, the charge is removed by the separation charger 216 to attenuate the electrostatic attraction force, so that the transfer belt 206 is separated from the end of the transfer belt 206. Particularly in a low humidity environment, the recording material also dries and the electrical resistance increases, so that the electrostatic attraction between the recording material and the transfer belt increases, and the effect of the separation charger 216 increases. Usually, the non-contact charger is used because the separation charger 216 removes the charge on the recording material P in a state where the toner image is not fixed. The output of the separation charger 216 is Vp-p = 10 kV, 50
An AC voltage of about 0 Hz is used. In addition, in order to prevent image defects such as toner scattering, 100
A plus or minus DC component of about μA may be superimposed.

The recording material P released from the end of the transfer belt 206 is conveyed to the fixing device 209. The fixing device 209 includes a fixing roller, a pressure roller, a heat-resistant cleaning member for cleaning each of the rollers, a heater installed in each roller, and a release agent oil such as dimethyl silicone oil applied to the fixing roller. And a thermistor that detects the surface temperature of the pressure roller and controls the fixing temperature. The recording material P on which the toner image is formed is fixed to the recording material P by fixing, a copy image is formed, and the copy image is discharged to a paper discharge tray.

After the transfer, the photosensitive drum 205 is cleaned and removed of the transfer residual toner by the cleaner 208.
Subsequently, the apparatus is prepared for the next latent image formation.

Further, the transfer belt 206 after the recording material P is separated is brought into contact with the conductive fur brush 210 grounded on the recording material carrying side and the drive roller 211 grounded opposite to the conductive fur brush 210, so that the transfer belt 206 The toner and other foreign matters remaining on the top are cleaned and the accumulated electrification is removed (static elimination). The conductive fur brush 210 may use a conductive web (nonwoven fabric).

Further, as cleaning means, various proposals have been made so far. A cleaning means in which the residual toner is scraped off by a cleaning blade made of an elastic material such as urethane rubber has a simple, compact structure. Because of its low cost and excellent toner removal function, it is widely used. As a rubber material for the cleaning blade, urethane rubber having high hardness, high elasticity, and excellent in abrasion resistance, mechanical strength, oil resistance, ozone resistance and the like is generally used.

In the above-described image forming apparatus, a pair of rollers including a suction charger 214 and a suction roller facing roller 215 is used as a means for electrostatically attracting the recording material P. A non-contact charger such as a corona discharge, or a contact charger using a charging member such as a charging roller, a charging brush, or a charging blade may be used as the transfer charging unit. However, when a non-contact system is used, the contact state between the recording material P and the transfer belt 206 is not guaranteed. Therefore, a separate pressing member is provided to secure the adhesion between the recording material P and the transfer belt 206. There is a need.

As described above, in order to stably carry out the electrostatic adsorption and conveyance of the recording material P, it is, of course, necessary to perform the adsorption charging of the entire width with respect to the paper width of the recording material P.

[0022]

However, when a cleaning blade for cleaning the transfer belt 206 by contacting the surface of the transfer belt 206 is used as a cleaning means for the transfer belt 206 as in the above-mentioned conventional example, the following will be described. There's a problem.

First, it has been confirmed by experiments that the frictional force between the transfer belt and the residue on the transfer belt by the cleaning blade has increased due to durability. This is considered to be due to the fact that the adhesion and affinity between the cleaning blade and the surface of the transfer belt and the residue on the transfer belt and the surface of the transfer belt are increased by the filming film formed by the durability, and the frictional force is increased. It is considered that the increase in the frictional force increases the shear stress of the cleaning blade, the shear stress between the toners, and the shear stress near the surface of the transfer belt.

As a result, chipping of the cleaning blade (local chipping of the edge), toner fusion due to an increase in the amount of heat generated due to an increase in the shear stress of the permanent set, and an increase in the internal stress of the transfer belt which may cause the transfer belt to break. It is considered that this leads to the occurrence of increased fatigue wear. If the amount of wear increases, the thickness of the transfer belt itself decreases, and the transfer belt may need to be replaced frequently.

Second, in recent years, it has been widely used not only as a function of a copying machine as described above but also as a printer. In addition, applications such as the feeder function and sorter function have been enhanced, and continuous operation of more than 4000 sheets per job has become possible. For example, in the case of 50 sheets / A4 machine, continuous operation is performed for 80 minutes or more even if a simple calculation is made. Under such circumstances, it is considered that the ambient temperature in the vicinity of the cleaning blade has reached nearly 50 ° C., and the temperature at the contact (nip) between the cleaning blade and the surface of the photoconductor has reached higher temperatures. Therefore, there is a problem that the frequency of occurrence of fixation or adhesion of the residue on the transfer belt surface increases, and the friction coefficient μ of the transfer belt surface increases.

Third, as the particle size of the toner becomes smaller, development with excellent dot reproducibility and resolution can be performed, and the sharpness and image quality of the toner image are improved. Since the specific surface area is increased, the adhesion of the toner per unit weight to the transfer belt is increased, and the cleaning performance of the transfer belt may be deteriorated. Further, as the particle size of the toner becomes smaller,
Since the fluidity of the toner deteriorates, a larger amount of the additive is required. However, this causes a problem that the cleaning blade is worn or chipped as described above, and a local streak is generated on the surface of the transfer belt. .

Fourth, in recent years, polymerized toners have been diversified in terms of improving transfer efficiency and requiring no release agent for fixing. However, toners produced by the polymerization method generally have high sphericity. If the sphericity increases, the counter blade method generally used in the related art often causes toner to pass through, and a local shearing force may be applied to the cleaning blade to cause edge chipping.

Accordingly, the present invention has been made in view of the above problems, and an object of the present invention is to prevent a cleaning failure and a reversal of a cleaning blade from occurring even when the friction coefficient of the transfer belt surface changes. It is to be.

[0029]

In order to achieve the above object, a typical configuration of the present invention is a recording material carrier for carrying and transporting a recording material, and a toner attached to the recording material carried on the recording material carrier. In an image forming apparatus including an image forming unit that forms an image and a cleaning unit that cleans the recording material carrier, the cleaning unit includes a cleaning blade, and the cleaning blade is swung with respect to the recording material carrier. While being supported so as to be able to move and contact freely, the swing fulcrum angle of the cleaning blade with respect to the recording material carrier is:
When the cleaning blade comes into contact with or separates from the recording material carrier surface, when the direction in which the cleaning blade comes into contact with the recording material carrier is positive, the cleaning blade is configured to have an angle of 0 ° or more and 15 ° or less, and the recording material It is characterized in that the amount of wear of the surface of the carrier during operation of the actual machine is not less than 0.01 μm and not more than 1.0 μm per 10,000 rotations.

The recording material carrier has a Young's modulus of 2.5.
It is characterized by having physical properties of × 10 ⁴ kg / cm ² or more and tensile strength of 1000 kg / cm ² or more.

Further, the initial starting friction coefficient of the recording material carrier is 0.1 or more and 0.5 or less.

Further, the recording material carrier has a polyimide resin layer on at least the surface.

The cleaning blade has a rebound resilience (%) of 0 <[blade temperature (° C.)] / [Rebound resilience (%)] ≦ 1.0 at least between 0 ° C. and 45 ° C. It is characterized by the following.

Further, the toner is a non-magnetic toner,
The average particle size is 6 μm to 10 μm, and the toner has a shape count
It is characterized by having at least a substantially spherical toner produced by a polymerization method in which SF-1 is in the range of 100 to 140 and SF-2 is in the range of 100 to 120.

The image forming means includes a plurality of image carriers for carrying toner images, a transfer charging member for transferring the toner images carried by each image carrier to a recording material carried by the recording material carrier. , And a plurality of toner images are sequentially transferred onto the recording material carried on the recording material carrier in a superimposed manner.

According to the present invention, the cleaning blade is supported so as to be able to swing and contact with the recording material carrier, and
The swing fulcrum angle of the cleaning blade with respect to the recording material carrier is 0 ° or more when the cleaning blade tends to come into contact with or separate from the surface of the recording material carrier, and when the direction in which the cleaning blade contacts the recording material carrier is defined as positive. 15 ° or less, and by setting the wear amount of the recording material carrier surface in actual machine operation to 0.01 μm or more and 1.0 μm or less per 10,000 rotations, even if the friction coefficient of the recording material carrier surface changes, An image forming apparatus that does not cause cleaning failure or reversal of a cleaning blade, that is, has a cleaning unit that can greatly improve the reliability of an image forming apparatus and can cope with a dramatic increase in productivity of the apparatus. A device can be provided.

[0037]

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

[First Embodiment] An image forming apparatus according to a first embodiment will be briefly described with reference to FIGS.

In the apparatus, first, second, third and fourth image forming units Pa, Pb, Pc and Pd are arranged in parallel, and toner images of different colors are used for a latent image, development and transfer process. Formed through

Each of the image forming sections Pa, Pb, Pc, and Pd includes a dedicated image carrier, in this embodiment, electrophotographic photosensitive drums 3a, 3b, 3c, and 3d. A toner image of each color is formed on 3c and 3d. A transfer belt 71 as a recording material carrier is installed adjacent to each of the photoconductor drums 3a, 3b, 3c, and 3d, and the toner images of each color formed on the photoconductor drums 3a, 3b, 3c, and 3d are transferred. The image is transferred onto the recording material P carried and conveyed on the belt 71. Further, the recording material P on which the toner images of each color have been transferred is fixed to the toner image by heating and pressing in the fixing device 9 and then discharged out of the device as a recorded image.

For image formation on the photosensitive drum, first, the original G is set on the original platen 10 with the surface to be copied facing downward. Next, copying is started by pressing the copy button. A document illumination lamp (not shown), a short focus lens array, and a CCD sensor are integrated into a unit to scan while irradiating the document, and the illumination scan light is imaged by the short focus lens array to form a CCD sensor. Is incident on. The CCD sensor includes a light receiving unit, a transfer unit, and an output unit. The light signal is converted into a charge signal in the CCD light receiving unit, and the transfer unit sequentially transfers the light signal to the output unit in synchronization with the clock pulse. The output unit converts the charge signal into a voltage signal, amplifies the signal, reduces the impedance, and outputs the voltage signal. The analog signal thus obtained is subjected to well-known image processing, converted into a digital signal, and sent to a printer unit. The printer section receives the image signal and forms an electrostatic latent image as follows. Photoconductor drums 3a, 3b, 3
c and 3d are driven to rotate in the direction of the arrow at a predetermined peripheral speed about the center support shaft, and during the rotation process, the magnetic brush chargers 2a, 2b, 2c and 2d which are driven to rotate in the direction of the arrow have a negative polarity. The solid-state laser element, which emits ON and OFF light corresponding to the image signal on the uniformly charged surface, is scanned by a rotating polygon mirror that rotates at high speed, and the original is charged on the photosensitive drum surface. An electrostatic latent image corresponding to the image is sequentially formed.

The charging and developing steps around the photosensitive drum will be described with reference to FIG. Each image forming unit Pa,
Since the structures of Pb, Pc, and Pd are the same, a description will be given here by exemplifying the periphery of the photosensitive drum 3a.

Here, as the photosensitive drum 3a used in the present invention, a commonly used organic photosensitive member or the like can be used, but preferably, the resistance is reduced on the organic photosensitive member.
When a material having a surface layer having a material of 10 ⁹ to 10 ¹⁴ Ωcm or an amorphous silicon photoreceptor is used, charge injection charging can be realized, which is effective in preventing ozone generation and reducing power consumption. Further, the chargeability can be improved. Therefore, in the present embodiment, a negatively charged organic photoreceptor, which is a photoreceptor drum having the following first to fifth five layers provided in order from the bottom on an aluminum drum base having a diameter of 30 mm, is used.

The first layer is a subbing layer, and is a conductive layer having a thickness of 20 μm provided for smoothing defects or the like of an aluminum substrate (hereinafter referred to as an aluminum substrate).

The second layer is a positive charge injection preventing layer, which serves to prevent positive charges injected from the aluminum substrate from canceling out negative charges charged on the surface of the photoreceptor, and comprises an amylan resin and methoxymethylated nylon. Is a 1 μm thick medium resistance layer whose resistance is adjusted to about 1 × 10 ⁶ Ωcm.

The third layer is a charge generation layer, which is a layer having a thickness of about 0.3 μm in which a disazo pigment is dispersed in a resin, and generates a positive and negative charge pair upon exposure.

The fourth layer is a charge transport layer in which hydrazone is dispersed in a polycarbamate resin, and is a P-type semiconductor. Therefore, the negative charges charged on the photoreceptor surface cannot move through this layer, and only the positive charges generated in the charge generation layer can be transported to the photoreceptor surface.

The fifth layer is a charge injection layer, which is a coating layer of a material in which ultrafine SnO ₂ particles are dispersed in a binder of an insulating resin. Specifically, a material in which 70% by weight of SnO ₂ particles with a particle size of about 0.03μm, which are made by doping antimony, which is a light-transmitting insulating filler, to an insulating resin and having a low resistance (conductivity) are dispersed in the resin. It is a coating layer.

The coating solution thus prepared was applied to a thickness of 3 μm by a suitable coating method such as dipping coating method, spray coating method, roll coating method, beam coating method, etc. to form a charge injection layer.

In this embodiment, a magnetic brush charging system is used as the charger. The magnetic brush charger 2a used in the present embodiment is provided on a rotatable non-magnetic sleeve 31 having an outer diameter of 16 mm and having a fixed magnet provided therein.
The magnetic particles are formed into a brush shape by a magnetic field, and the magnetic particles are transported as the non-magnetic sleeve 31 rotates. Also,
The non-magnetic sleeve 31 rotates in the counter direction (in the direction of the arrow in FIG. 3) with respect to the photosensitive drum 3a. It rotates at a rotation speed of 150 mm / sec. By applying a charging voltage to the non-magnetic sleeve 31, electric charges are given from the magnetic particles to the photosensitive drum 3a, and the non-magnetic sleeve 31 is charged to a potential corresponding to the charging voltage. The higher the rotation speed, the better the charging uniformity tends to be.

The magnetic carrier used as the charging member has an average particle diameter of 10 to 100 μm and a saturation magnetization of 20 to 100 μm.
250 emu / cm ³ and a resistance of 1 × 10 ² to 1 × 10 ¹⁰ Ωcm, preferably a resistance of 1 × 10 ⁶ Ωcm or more in consideration of the presence of insulation defects such as pinholes in the photosensitive drum. It is preferable to use one. In order to improve the charging performance, it is better to use one having as small a resistance as possible.In this embodiment, the average particle diameter is 25 μm, and the saturation magnetization is 200 emu /.
Magnetic particles of cm ³ and a resistance of 5 × 10 ⁶ Ωcm are used.

Here, the resistance value of the carrier has a bottom area of 22
After 2 g of the carrier was put into an 8 mm ² metal cell, the weight was applied at 6.6 kg, and a voltage of 100 V was applied to measure.

As the magnetic particles, a resin carrier formed by dispersing magnetite as a magnetic material in a resin and dispersing carbon black for conductivity and resistance adjustment;
Alternatively, a material in which the surface of a single magnetite such as ferrite is oxidized and reduced to adjust the resistance, or a material in which the surface of a single magnetite such as ferrite is coated with a resin to adjust the resistance may be used.

The nip width formed with respect to the photosensitive drum is adjusted to be approximately 6 mm.

Next, the amplitude of the applied bias and the charging potential in the first cycle when a rectangular AC voltage having a frequency of 1000 Hz is applied to the charger will be described. By increasing the amplitude, the difference between the DC component of the applied bias and the charged potential in the first cycle becomes smaller. More specifically, assuming that the DC component of the bias applied to the charger is Vdc and the surface potential on the photosensitive drum 3a charged at this time is Vs, the difference ΔV = | Vdc−Vs | When the voltage is 40 V or less, the uniformity of charging is improved. Therefore, in the present embodiment, a rectangular AC voltage 1
By applying a bias in which 000 Hz and 800 V were superimposed on the charger, good charging properties could be obtained.

Here, the developing step will be described. FIG.
In the drawings, reference numeral 1a denotes a developing device for two-component magnetic brush development used in the present embodiment. In the figure, 41 is a developing sleeve, 42 is a magnet roller fixedly arranged in the developing sleeve 41, 43 and 44 are stirring screws, 45 is a regulating blade arranged to form a thin layer of developer on the surface of the developing sleeve 41, 46 is a developing container. At least at the time of development, the developing sleeve 41 is arranged so that the area closest to the photosensitive drum 3a is about 500 μm, and is set so that the developer can be developed in contact with the photosensitive drum 3a. ing. In the two-component developer used in the present embodiment, the toner particles have an average particle diameter of 6 μm manufactured by a pulverization method.
A negatively charged toner having a mean particle diameter of 20 nm and titanium oxide having an average particle diameter of 1% externally added at a weight ratio of 1% was used, and a magnetic carrier having a saturation magnetization of 205 emu / cm ^{3 and} an average particle diameter of 35 μm was used. A mixture of this toner and a carrier at a weight ratio of 6:94 was used as a developer.

Here, the developing process of visualizing the electrostatic latent image formed on the photosensitive drum 3a by the two-component magnetic brush method using the developing device 1a and the circulation system for the developer will be described. . First, as the developing sleeve 41 rotates, N
In the process of being transported from the S2 pole to the N1 pole, the developer pumped by the two poles is regulated by the regulating blade 45 arranged perpendicular to the developing sleeve 41, and a thin layer is formed on the developing sleeve 41. . Here, when the developer formed as a thin layer is conveyed by the developing main pole S1, a spike is formed by magnetic force. The electrostatic latent image is developed by the developer formed in the spike shape.
The developer on the developing sleeve 41 is returned into the developing container 46 by the repulsive magnetic field of the pole.

A DC voltage and an AC voltage are applied to the developing sleeve 41 from a power supply (not shown). In this embodiment, the DC voltage is -500 V, the AC voltage is Vpp = 1500 V, Vf
= 2000 Hz is applied. In general, in the two-component developing method, when an AC voltage is applied, the developing efficiency increases, and the image becomes high-quality, but fogging easily occurs. For this reason, usually, by providing a potential difference between the DC voltage applied to the developing device 1a and the surface potential of the photosensitive drum 3a,
The fog is prevented.

The developing devices 1a, 1b, 1c, 1 shown in FIG.
A predetermined amount of yellow, magenta, cyan, and black toners is filled in d by a supply device (not shown). Developing devices 1a, 1b, 1c, 1
d develops the latent images on the photosensitive drums 3a, 3b, 3c, 3d, respectively, and visualizes them as a yellow toner image, a magenta toner image, a cyan toner image, and a black toner image.

As the characteristics of the color toner, first, as a two-component developer, a mixture of a polymerized toner produced by a suspension polymerization method and a resin magnetic carrier produced by a polymerization method was used. The T / D ratio of the obtained developer was 8%. The magnetic carrier used had a magnetization of 100 emu / cm ³ in a magnetic field of 1 kOe, a number average particle diameter of 40 μm, and a specific resistance of 10 ¹³ Ωcm. As the non-magnetic polymerized toner, a toner having a weight average particle diameter of 8 μm, a specific gravity of 1.05 g / cm ³ and an average charge per unit mass of 25 μc / g was used.

The polymerized toner used in the present invention includes:
A substantially spherical toner having a shape factor SF-1 in the range of 100 to 140 and SF-2 in the range of 100 to 120 is preferable for maintaining high transfer efficiency. In the present invention, the shape factors SF-1 and SF-2
With a scanning electron microscope FE-SEM (S-8) manufactured by Hitachi, Ltd.
Using (00), 100 toner particles are randomly sampled, and the image information is introduced into an image analyzer (Luzex3) manufactured by Nireco Corporation via an interface, analyzed, and calculated by the following equation. The obtained values were used as shape factors SF-1 and SF-2.
Defined.

[0062]

(Equation 1)

By using such a spherical toner, a transfer efficiency of at least 95% can always be ensured, which is an essential component of a cleaningless system.

This toner image is then transferred to the recording material P by the transfer device 7. As shown in FIG.
1 suspends an endless transfer belt 71 as a recording material carrier between a driving roller 72 and a driven roller 73, and is rotated in a direction indicated by an arrow in FIG. Further, a transfer charging blade 6 is provided in the transfer device 7.
a, 6b, 6c, 6d.
a, 6b, 6c, and 6d generate a pressing force from the inside of the transfer belt 71 in the direction of each of the photosensitive drums 3a, 3b, 3c, and 3d, and are supplied with power from a high-voltage power supply so that the toner from the back side of the recording material P Then, the toner images on the photosensitive drums 3a, 3b, 3c, 3d are sequentially transferred to the upper surface of the recording material P by performing the charging of the opposite polarity.

Here, the recording material P is transferred from the sheet feeding and conveying device to the photosensitive member.
Synchronize with the rotation of the drums 3a, 3b, 3c, 3d and
With a correct timing, the photosensitive drums 3a, 3b,
Conveyed sequentially to each transfer section formed by 3c, 3d and transfer belt 71
Is done. In the present embodiment, the transfer belt 71 is
Conductive filler such as carbon black dispersed in body resin
It is made of a sheet with resistance adjustment
In the state, the volume resistivity is 10 ¹²Ωcm, 75μm thick polyimide
Using resin, overlap both ends
Endless shape or joint
The belt has no eyes (seamless).

A transfer belt 71 as a recording material carrier
Uses a belt having physical properties such that the amount of wear of the surface thereof in actual machine operation is not less than 0.01 μm and not more than 1.0 μm per 10,000 rotations. Specifically, the transfer belt 71 in the present embodiment has a tensile strength of 3200 kg / cm ² and a Young's modulus of 6.0 × 10 ⁴ kg / c.
m ² , surface roughness Rz 0.92 μm (manufactured by Kosaka Seisakusho, length 0.8, cu
The property value of toff0.08) is used. According to the transfer belt 71, the wear amount on the actual machine was 0.05 μm / 10,000 rotations.

Further, the transfer charging blades 6a, 6b, 6c,
For 6d, the resistance is 1 × 10 ⁵ to 1 × 10 ⁷ Ω and the plate thickness is 2
mm and a length of 306 mm are used. The transfer is performed by applying a bias of +15 μA to the transfer charging blades 6a, 6b, 6c, 6d by constant current control.

In this manner, each of the photosensitive drums 3a, 3
The toner images formed on b, 3c and 3d are electrostatically transferred onto a recording material by transfer charging blades 6a, 6b, 6c and 6d.

As described above, image formation and transfer in the first to fourth image forming units Pa to Pd are sequentially performed in the same manner.

The recording material P is supplied from the paper feed tray 17, is supplied to the transfer belt 71 via the transport roller and the registration roller 12, and is conveyed by the transfer belt 71 so that each photosensitive drum 3
The sheets are sequentially sent to the transfer sections facing a, 3b, 3c, and 3d.

When the transfer belt 71 is rotated by the driving roller 72 and reaches a certain speed, the recording material P is transferred to the registration roller.
The recording material is sent out from 12 to the transfer belt 71, and the recording material is conveyed toward the transfer unit. At the same time, the image writing signal is ON
The image is formed on each photosensitive drum at a predetermined timing based on the above. Then, the transfer charging blades 6a, 6b, 6c, 6d apply an electric field or electric charges in the lower transfer section of each of the photoconductor drums 3a, 3b, 3c, 3d, so that the photoconductor drums 3a, 3b, 3c, 3d. The toner image formed thereon is transferred to the recording material P. Before transfer, the recording material P is transferred to the attraction charger 11a and the attraction roller 11 facing the attraction charger.
b, is held on the transfer belt 71 by electrostatic attraction,
The sheet is conveyed to the fixing device 9.

The adsorbing charger 11a uses a charging roller for the purpose of stabilizing the adhesion between the recording material P and the transfer belt 6 simultaneously with charging.

Next, the recording material P on which the toner image has been transferred is removed from the end of the transfer belt 71 by being discharged by the separation charger 16 at a downstream portion of the transfer belt 71 in the transport direction and attenuating the electrostatic attraction force. I do. Particularly in a low humidity environment, the recording material also dries and the electric resistance increases, so that the electrostatic attraction force between the recording material and the transfer belt 71 increases, and the effect of the separation charger 16 increases. The non-contact charger is used as the separation charger 16 because the recording material P is de-charged in a state where the toner image is not fixed. The output of the separation charger 16 uses Vp-p = 10 kV and an AC voltage of about 500 Hz. In order to prevent image defects such as toner scattering, a plus or minus DC component of about 100 μA is superimposed on the AC output.

The recording material P detached from the end of the transfer belt 71
Is transported to the fixing device 9. The fixing device 9 includes a fixing roller
The pressure roller 51 includes a pressure roller 52, a heat-resistant cleaning member for cleaning each roller, and a thermistor for detecting the surface temperature of a heater installed in each roller and controlling the fixing temperature. Recording material P on which toner image is formed
Is fixed to the recording material P by fusing, a full-color copy image is formed, and the image is discharged onto the discharge tray 18.

In the figure, 4a, 4b, 4c, 4d
Is a fur brush made of rayon. The transfer residual toner, which coexists in both positive and negative polarities, has a positive polarity.
This is for facilitating the collection of the transfer residual toner in a, 2b, 2c and 2d, and the applied bias is + 500V.

The transfer belt 71 after the recording material P is separated is contacted with the conductive fur brush 8 grounded on the recording material carrying side and the driving roller 72 grounded opposite to the conductive fur brush 8. The contact removes toner and other foreign matters remaining on the transfer belt 71 and removes (discharges) accumulated charges. Further, the toner remaining on the transfer belt 71 is wiped off by bringing the cleaning blade 5 into contact with the surface of the transfer belt 71.

The cleaning blade 5 constituting the cleaning means for the transfer belt 71 has a rubber hardness of 77 ° (Jsi
A), composed of a rebound resilience of 45% (23 ° C.), a plate thickness of 2 mm, and a free length of 8 mm. As shown in FIG. 2, the cleaning unit having the cleaning blade 5 is supported so as to be able to swing and contact with the transfer belt 71 so that the swing fulcrum angle of the cleaning blade 5 with respect to the transfer belt 71 is equal to the cleaning blade angle. When the transfer belt 5 comes into contact with or separates from the transfer belt surface, the transfer belt 71
When the direction in contact with is positive, the angle is set to 0 ° or more and 15 ° or less. In this embodiment, the cleaning unit includes a swing angle of 0 °, a contact angle of 25 °, and a transfer belt 71.
And a total pressure of 1.5 kgf.

In FIG. 2, 55 is the swing center of the cleaning unit, and θ is the swing fulcrum angle of the cleaning unit.

As shown in FIG. 4, in the first embodiment, even if the coefficient of kinetic friction of the transfer belt 71 changes from the initial value of 0.3 to 0.6 after the endurance, the load of the transfer belt increases in the above configuration. No image defects such as reversal of the cleaning blade due to the above and color misregistration due to a large load of the transfer belt motor did not occur. As a result of performing an image endurance test, over 1 million sheets of the above-mentioned transfer belt and 500,000 sheets of the cleaning blade, a high-quality image was stably maintained over a long period of time without any problem that appeared on the image.

[Second Embodiment] Next, an image forming apparatus according to a second embodiment will be briefly described. In this embodiment, since the configuration other than the transfer belt is the same as that of the above-described first embodiment, detailed description will be omitted. In the present embodiment, the transfer belt 71 has a tensile strength of 4000 kg / cm ² ,
Young's modulus 7.0 × 10 ⁴ kg / cm ² , surface roughness Rz 0.52 μm (manufactured by Kosaka Seisakusho, length 0.8, cutoff 0.08), initial dynamic friction coefficient 0.2
A property value of 0 (HEIDON, Tribogear Muse TYPE: 94B) is used.

As shown in FIG. 4, in the second embodiment, the wear amount of the transfer belt surface on the actual machine was 0.3 μm / 10,000 rotations in the above configuration. As a result of the image endurance test, over 1 million sheets of the transfer belt and 500,000 sheets of the cleaning blade, high quality images were stably maintained without any problems that appeared on the image for a long time.

[Third Embodiment] Next, an image forming apparatus according to a third embodiment will be briefly described. In this embodiment, since the configuration other than the swing fulcrum angle and the rebound resilience / hardness of the cleaning blade, which is the cleaning member of the transfer belt, is the same as that of the above-described first embodiment, detailed description is omitted. In the present embodiment, the cleaning blade 5 constituting the cleaning means of the transfer belt 71 has a swing fulcrum angle of 10 °, a rubber hardness of 70 ° (JisA), and a rebound resilience of 30% (23 ° C.).

As shown in FIG. 4, in the third embodiment, the wear amount of the transfer belt surface on the actual machine was 0.05 μm / 10,000 rotations in the above configuration. Even if the dynamic friction coefficient of the transfer belt 71 changes from 0.2 in the initial stage to 0.5 after the endurance, image defects such as reversal of the cleaning blade due to an increase in the load on the transfer belt and color misregistration due to a large load on the transfer belt motor occur. Did not. As a result of the image endurance test, 1 million transfer belts and 5 cleaning blades were used.
Over the long term of 100,000 sheets, no high-quality images were stably maintained without any noticeable defects.

[Comparative Examples] In the following, three comparative examples with the above-described embodiment to which the present invention is applied will be described.

First, an image forming apparatus according to Comparative Example 1 will be briefly described. In Comparative Example 1, the configuration was the same as that of the above-described first embodiment except for the swing fulcrum angle of the cleaning blade of the transfer belt. In Comparative Example 1, the cleaning blade of the transfer belt has a swing fulcrum angle of 30 °.

As shown in FIG. 4, in Comparative Example 1, in the above configuration, the dynamic friction coefficient of the transfer belt was 0.5%.
, The cleaning blade was inverted during continuous paper passing.

Next, an image forming apparatus according to Comparative Example 2 will be briefly described. In Comparative Example 2, the configuration was the same as that of the above-described first embodiment except for the swing fulcrum angle of the cleaning blade of the transfer belt. In Comparative Example 2, the cleaning blade of the transfer belt has a swing fulcrum angle of −15 °.

As shown in FIG. 4, in Comparative Example 2, when the number of sheets passed was about 50,000 in the above-described configuration, cleaning failure occurred at the time of startup.

Next, an image forming apparatus according to Comparative Example 3 will be briefly described. Note that, in Comparative Example 3, since the configuration other than the transfer belt was the same as that of the above-described first embodiment, detailed description is omitted. In Comparative Example 3, the transfer belt was made of polycarbonate, and had a tensile strength of 660 kg / cm ² , a Young's modulus of 2.0 × 10 ⁴ kg / cm ² , and a surface roughness Rz of 0.60 μm (manufactured by Kosaka Seisakusho, length 0.8, cutoff 0.08). With the physical properties of

As shown in FIG. 4, in Comparative Example 3, in the above configuration, the amount of wear of the transfer belt on the actual machine was
It was 2.0 μm / 10,000 revolutions. As a result of performing an image endurance test and passing 100,000 sheets, the surface roughness of the transfer belt was Rz 4.50 μm.
(Manufactured by Kosaka Seisakusho, length 0.8, cutoff 0.08), and a streak-like cleaning image defect occurred.

[Fourth Embodiment] FIG. 5 is a schematic structural view showing an embodiment of the image forming apparatus of the present invention.

As shown in FIG. 5, the present image forming apparatus has a plurality of image forming units Py, Pm, Pc, and Pk.
The image forming units Py to Pk are arranged in this order on the track on the upper side of the intermediate transfer belt 105 along the moving direction of the intermediate transfer belt 105.

Image forming units Py, Pm, Pc, Pk
Have photoreceptor drums 101y, 101m, 101c, and 101k, respectively, and form negatively charged yellow, magenta, cyan, and black images as color separation component images of a full-color image. In this embodiment, each of the photoconductor drums 101y to 101k is an OPC (organic) photoconductor having a diameter of 30 mm and a length of 300 mm, and is rotated counterclockwise by an arrow at a peripheral speed of 100 mm / sec (same as the process speed). Driven.

The photosensitive drums 101y, 101m, 101c, 101k
Around the primary chargers 102y, 102m, 102c, 102k,
Image exposing units 104y, 104m, 104c, 104k, developing unit 103
y, 103m, 103c, 103k, primary transfer rollers 106y, 106
m, 106c and 106k are provided.

In the present embodiment, the primary chargers 102y to 102k comprise corotron type corona chargers. To form an image, the photosensitive drums 101y to 101k are rotated, and in the course of this rotation, first, the surfaces of the photosensitive drums 101y to 101k are uniformly charged by the primary chargers 102y to 102k. In the present embodiment, the surfaces of the photosensitive drums 101y to 101k are substantially
Was uniformly charged.

The image exposure units 104y to 104k do not require an optical path length, and are LE scanners as solid-state scanners that are advantageous for downsizing the apparatus.
A D array was used. The individual LEDs of each of the LED arrays 104y to 104k are controlled to blink (ON / OFF) in response to a time-series electric digital pixel signal of original image information input from an image reading device (not shown). The surface of the uniformly charged photoconductor drums 101y to 101k is subjected to image exposure, and the surface potential of the exposed portions of the photoconductor drums 101y to 101k is attenuated to form an electrostatic latent image.

Developing devices 103y to 103k as developing means include:
In the present embodiment, a two-component magnetic brush developing device is used. The developing devices 103y to 103k are provided with a developing sleeve, a magnet roller fixedly arranged in the developing sleeve, and a developer on the surface of the developing sleeve, in a developing container containing a two-component developer in which a non-magnetic toner and a magnetic carrier are mixed. It is provided with a regulating blade or the like for applying a layer.

The developing unit 103y in the yellow image forming unit Py contains a two-component developer containing a yellow toner, and an electrostatic latent image corresponding to the yellow image formed on the surface of the photosensitive drum 101y. The image is reverse developed and visualized as a yellow toner image. Developing units 103m, 1 in image forming units Pm, Pc, Pk of other colors
Similarly, 03c and 103k reversely develop the respective electrostatic latent images in the same manner and visualize them as magenta, cyan, and black toner images.

The intermediate transfer belt 105 is an endless belt as an intermediate transfer member, and is wound around three rollers of a driving roller 107, a secondary transfer facing roller 108, and a driven roller 109. This intermediate transfer belt 105 is
The photoconductive drums 101y to 101k are arranged so as to be in contact with the lower surfaces of the photoconductive drums 101y to 101k, and are driven to rotate in the counterclockwise direction of the arrow at the same peripheral speed as the photosensitive drums 101y to 101k.

The primary transfer rollers 106y to 106k are arranged inside the belt portion on the upper track of the intermediate transfer belt 105 so as to face the respective photosensitive drums 101y to 101k. The primary transfer roller 106y of the yellow image forming unit Py is connected to the photosensitive drum 10 with the intermediate transfer belt 105 interposed therebetween.
The primary transfer portion 121y is formed in contact with the lower surface of 1y. Similarly, the primary transfer rollers 106m, 106m for the image forming units Pm, Pc, Pk for magenta, cyan, and black.
c and 106k are in contact with the lower surfaces of the photosensitive drums 101m, 101c and 101k, respectively, with the intermediate transfer belt 105 interposed therebetween to form primary transfer portions 121m, 121c and 121k.

To each of the primary transfer rollers 106y to 106k, a transfer bias having a polarity opposite to that of the toner is applied from a primary transfer power source (not shown), and the toner image on the photosensitive drums 101y to 101k is applied by the application of the transfer bias. In each of the primary transfer sections 121y to 121k, the intermediate transfer belt 105
Is primary-transferred electrostatically by being superimposed on the surface of. As a result, a full-color image is formed on the intermediate transfer belt 105 by superimposing and synthesizing the yellow, magenta, cyan, and black toner images.

According to the present invention, the image forming apparatus is a cleanerless system employing the simultaneous development and cleaning system, and the developing units 103y to 103k transfer the toner images on the respective photosensitive drums 101y to 101k. It also serves as a cleaning means for removing the transfer residual toner remaining later. Therefore, none of the image forming units Py to Pk has a dedicated cleaning device for the photosensitive drums 101y to 101k. However, development may not be performed at the same time as cleaning.

The secondary transfer facing roller 1 of the intermediate transfer belt 105
At 08, a secondary transfer roller 110 which is in contact with the intermediate transfer belt 105 with the intermediate transfer belt 105 therebetween to form a secondary transfer portion 111 is arranged. The full-color image formed on the intermediate transfer belt 105 reaches the secondary transfer unit 111 with the rotation of the intermediate transfer belt 105, and the secondary transfer roller 110 has a secondary transfer power source (not shown) having a polarity opposite to that of the toner. By applying the transfer bias, the secondary transfer is collectively performed on the surface of the recording material (recording paper) P supplied to the secondary transfer unit.

The recording material P is accommodated in a paper feed cassette 112 arranged below the image forming apparatus. Cassette 112
The recording material P in the inside is taken out and conveyed by a paper feed roller 113, and a pair of registration rollers 114 and 11 in front of the secondary transfer unit 111.
After being temporarily stopped at 5, the recording material P is supplied to the secondary transfer unit 111 at the same time as the leading end of the image on the intermediate transfer belt 105 reaches the secondary transfer unit 111.

The recording material P on which the full-color image has been transferred by the secondary transfer unit 111 is separated from the surface of the intermediate transfer belt 105 and introduced into the fixing device 116, where it undergoes heat fixing of the image to form a full-color permanent image. The tray 117 outside the device is
Is discharged to

The intermediate transfer belt 105 after the completion of the secondary transfer
After the transfer, the untransferred toner remaining on the surface in the secondary transfer and the paper dust attached from the recording material P are cleaned and removed by the belt cleaning device 118 installed at the driven roller 109. The belt cleaning device 118 has the same configuration as that of the first embodiment.

In the present invention, the image forming apparatus forms a full-color image on the intermediate transfer belt 105 while the intermediate transfer belt 105 makes one rotation using a plurality of photosensitive drums. Therefore, in the case of an image forming apparatus that forms a full-color image by rotating the intermediate transfer body a plurality of times using one photoconductor drum, the cleaning device for the intermediate transfer body needs to perform a contact / separation operation with respect to the intermediate transfer body. But
According to the present invention, the contact / separation operation of the belt cleaning device 118 is not required, and the cleaning blade 119 can be kept in contact with the intermediate transfer belt 105 at all times.

According to the present embodiment, as described above, the OPC photoconductors are used as the photoconductor drums 101y to 101k. However, this photoconductor drum is provided on the peripheral surface of the aluminum base as the conductive base. Has been formed,
The OPC photosensitive layer is formed by sequentially laminating the following four layers.

The first layer is an undercoat layer, which is provided for smoothing out defects or the like of the aluminum substrate, and is a conductive layer having a thickness of 20 μm.

The second layer is a positive charge injection preventing layer, which serves to prevent the positive charge injected from the aluminum substrate from canceling out the negative charge charged on the surface of the photoreceptor. 1 × 10 ⁶
This is a medium resistance layer having a thickness of 1 μm and a resistance adjusted to about Ωcm.

The third layer is a charge generation layer, which is a layer having a thickness of about 0.3 μm in which a disazo pigment is dispersed in a resin, and generates positive and negative charge pairs upon exposure.

The fourth layer is a charge transport layer, and is made of a P-type semiconductor in which hydrazone is dispersed in a polycartinate resin.
Therefore, the negative charges charged on the photoreceptor surface cannot move through this layer, and only the positive charges generated in the charge generation layer can be transported to the photoreceptor surface.

The intermediate transfer belt 105 is made of, for example, a polyurethane resin, a polyester resin,
Polyethylene resin, polyolefin resin, polyamide resin, polyimide resin, polyvinyl chloride resin,
A material in which conductive carbon particles, metal powder, and the like are dispersed and mixed in a polyethylene resin, a fluorine resin, or the like is used.

In the present embodiment, a material using carbon particles for the polyimide resin is used for the intermediate transfer belt 105.
The volume resistivity is preferably in the range of 10 ⁶ to 10 ¹⁴ Ωcm. If the volume resistivity of the intermediate transfer belt 105 is 10 ⁶ Ωcm or less, there arises a problem that an image is blurred, becomes thick, or a transfer efficiency is changed when images having different image ratios are formed. In the case of the intermediate transfer belt 105 of 10 ¹⁴ Ωcm or more, the potential between the intermediate transfer belt 105 and the photosensitive drums 101y to 101k or between the intermediate transfer belt 105 and the recording material P due to the potential of the intermediate transfer belt 105 becoming too large during toner transfer. An abnormal discharge occurs during this period, resulting in an image defect. In the present embodiment, the thickness of the intermediate transfer belt 105 is 100 μm, and the volume resistivity is 10 ¹¹
A Ωcm seamless belt was used.

As described above, the belt cleaning device 118 is a cleaning blade 119 for a plate-like rubber blade.
And a container 12 for storing waste toner and paper powder.
Or a transport screw for transporting waste toner and paper powder to a large-capacity waste toner container provided at another location. As the cleaning blade 119, a polyurethane rubber was used, of which the tensile stress at the time of 5% elongation (JIS K6301) was 80 to 120 kg / cm ² among various physical properties of the rubber. The tensile stress was measured by cutting a rubber plate forming a cleaning blade into a dumbbell shape and pulling both ends.

When the rubber tensile stress of the cleaning blade 119 is 80 kg / cm ² or less, the intermediate transfer belt 1
Even if the pressing force to 05 is increased, the pressure obtained as the peak value does not easily increase, and if it is attempted to obtain sufficient cleaning performance of the transfer residual toner and paper dust on the intermediate transfer belt 105. It is necessary to apply an excessive pressure, so that the life of the blade 119 and the intermediate transfer belt 105 is shortened, and the blade 119 is turned.
When the rubber tensile stress of the blade 119 is 120 kg / cm ² or more, the rebound resilience also increases,
Vibration at the abutment portion of the 119 with the intermediate transfer belt 105 is increased, and cleaning failure and blade turning are likely to occur. Further, since the permanent set of the blade tends to increase, a problem also occurs in terms of durability.

When the image forming apparatus of the present embodiment having the above-described configuration was used, an image endurance test was carried out. As a result, the intermediate transfer belt and the cleaning blade were imaged over a long period of 1,000,000 sheets and 500,000 sheets, respectively. High quality images were stably maintained without any problems that appeared to be apparent.

[0118]

As described above, according to the present invention,
The cleaning blade is pivotally supported on and separated from the recording material carrier, and the pivot angle of the cleaning blade with respect to the recording material carrier is such that the cleaning blade contacts and separates from the recording material carrier surface. 0 ° when the direction of contact with the recording material carrier is positive.
When the friction coefficient of the surface of the recording material carrier is changed by setting the wear amount on the actual surface operation of the recording material carrier to 0.01 μm or more and 1.0 μm or less per 10,000 rotations, the configuration is set to 15 ° or less. An image forming apparatus which does not cause cleaning failure or reversal of a cleaning blade, that is, which can greatly improve the reliability of an image forming apparatus and has a cleaning means capable of coping with a drastic increase in productivity of the apparatus. An apparatus can be provided.

[Brief description of the drawings]

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

FIG. 2 is an explanatory diagram showing a relationship between a transfer belt and a cleaning blade.

FIG. 3 is a schematic cross-sectional view showing a configuration around a photosensitive drum in the image forming apparatus.

FIG. 4 is a table showing a relationship between a transfer belt, a cleaning blade, and a wear amount and a result of an endurance test.

FIG. 5 is a schematic configuration diagram showing an embodiment of the image forming apparatus of the present invention.

FIG. 6 is a sectional view of a conventional image forming apparatus.

[Explanation of symbols]

 G: Original P: Recording material Pa, Pb, Pc, Pd: Image forming unit Py, Pm, Pc, Pk: Image forming unit 1a, 1b, 1c, 1d: Developing device 2a, 2b, 2c, 2d: Magnetic brush charging Units 3a, 3b, 3c, 3d: Photoconductor drums 4a, 4b, 4c, 4d: Fur brush 5: Cleaning blades 6a, 6b, 6c, 6d: Transfer charging blade 7: Transfer device 8: Conductive fur brush 9: Fixing Apparatus 10: Document table 11a: Attraction charger 11b: Attraction charger opposing roller 12: Registration roller 16: Separation charger 17: Feed tray 18: Discharge tray 31: Non-magnetic sleeve 41: Developing sleeve 42: Magnet roller 43 , 44… stirring screw 45… regulating blade 46… developing container 51… fixing roller 52… pressure roller 55… swing center 71… transfer belt 72… drive roller 73… driven Rollers 101y, 101m, 101c, 101k Photoconductor drums 102y, 102m, 102c, 102k Primary chargers 103y, 103m, 103c, 103k Developing units 104y, 104m, 104c, 104k Image exposing unit 105 Intermediate transfer belt 106y , 106m, 106c, 106k ... primary transfer roller 107 ... drive roller 108 ... secondary transfer opposing roller 109 ... driven roller 110 ... secondary transfer roller 111 ... secondary transfer section 112 ... paper feed cassette 113 ... paper feed rollers 114, 115 … Registration roller pair 116… Fixer 117… Tray 118… Belt cleaning device 119… Cleaning blades 121y, 121m, 121c, 121k… Primary transfer unit 122… Container

Claims (7)

[Claims] A recording material carrier that carries and conveys the recording material;
In an image forming apparatus including an image forming unit that forms a toner image on a recording material carried on the recording material carrier, and a cleaning unit that cleans the recording material carrier, the cleaning unit includes a cleaning blade,
The cleaning blade is pivotally supported on and separated from the recording material carrier, and the pivot angle of the cleaning blade with respect to the recording material carrier is such that the cleaning blade contacts the surface of the recording material carrier. ,
When the direction of contact with the recording material carrier is positive, the recording material carrier is configured to have an angle of 0 ° or more and 15 ° or less, and the amount of wear of the surface of the recording material carrier in actual machine operation is 10%.
An image forming apparatus characterized by being configured to have a thickness of 0.01 μm or more and 1.0 μm or less per 000 rotations. 2. The recording material carrier has a Young's modulus of 2.5 × 10 ^4.
2. The image forming apparatus according to claim 1, wherein the image forming apparatus has physical properties of not less than kg / cm ^{2 and not} less than 1000 kg / cm ² . 3. An initial dynamic friction coefficient of the recording material carrier is:
The image forming apparatus according to claim 1, wherein the value is 0.1 or more and 0.5 or less. 4. The image forming apparatus according to claim 2, wherein the recording material carrier has a polyimide resin layer on at least the surface. 5. The cleaning blade has a rebound resilience (%) of 0 <[Blade temperature (° C.)] / [Rebound resilience (%) ≦ 1.0 at least between 0 ° C. and 45 ° C. The image forming apparatus according to claim 1, wherein: 6. The toner is a non-magnetic toner, has an average particle diameter of 6 μm to 10 μm, and has a shape count of SF-1.
The image forming apparatus according to claim 1, wherein the image forming apparatus has at least a substantially spherical toner produced by a polymerization method, wherein the toner has a particle size of 100 to 140 and the SF-2 falls within a range of 100 to 120. 7. The image forming means includes: a plurality of image carriers for carrying toner images; a transfer charging member for transferring a toner image carried by each image carrier to a recording material carried by the recording material carrier; 7. The image forming apparatus according to claim 1, wherein a plurality of toner images are sequentially transferred onto the recording material carried by the recording material carrier in a superimposed manner. apparatus.