JPS628187A - Cleaning device - Google Patents

Abstract

PURPOSE:To remove a developer component from an image carrier completely by providing the 1st cleaning means on one surface side of the image carrier and also providing the 2nd cleaning means which removes the remaining developer component after the cleaning of the 1st cleaning means on the other surface side of the image carrier. CONSTITUTION:When a photosensitive drum 1 rotates and slides on a blade 8a, the photosensitive drum 1 is cleaned completely and a valve 86 is slid on a collecting roller 85 to prevent the remaining toner Tb collected in the photosensitive drum 1 from leaking. A scraper 87 slides on the collecting roller 85 in the photosensitive drum 86 to scrape off the remaining toner Tb sticking on the collecting roller 85. Thus, the toner remaining on the photosensitive drum is collected by the 1st cleaning means 8-1 firstly and the toner which further remains is collected by the 2nd cleaning means 8-2. Consequently, the cleaning of the photosensitive drum is perfect and no toner remains on the photosensitive body, so that there is no trouble to the next recording.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to a cleaning device, and for example, to a cleaning device for cleaning an image bearing member of an electrophotographic device, a magnetic printing device, or the like.

BACKGROUND OF THE INVENTION First, an example of recording by an electrophotographic apparatus equipped with a conventional cleaning device will be described with reference to FIG.

A drum-shaped photoreceptor 1 having a photosensitive layer of selenium or the like on its surface rotates in the direction of arrow J, is uniformly charged by a charger 2, and light that travels on an original image (original document) (not shown) is transferred to the photoreceptor l. An electrostatic latent image is formed on the photoreceptor 1 by irradiating the top.

Next, the electrostatic latent image is developed into a toner image by the developing device 3. Next, the toner image is charged by a charging electrode 9 and transferred to a recording paper P by a transfer pole 4, and the recording paper P is separated from the photoreceptor 1 by a separation pole 5 and fixed by a fixing device 6. On the other hand, the photoreceptor 1 is cleaned by the removing electrode 7 and the cleaning device 8 to remove residual toner that has not been completely transferred to the recording paper P.

As shown in FIG. 13, the cleaning device 8 includes a cleaning blade (hereinafter referred to as a blade) 8a, a sponge roller 8b, and a screw 8c.
a slides on the photoconductor 1 and scrapes off the toner Ta remaining on the photoconductor 1, and the scraped toner Ta is transferred to the screw 8 by the sponge roller 78b as shown by the arrow.
c, and is conveyed to a waste toner storage section (not shown) by the screener 5-8c. When the cleaning/cleaning is completed, the blade 8a is separated from the photoreceptor 1.

However, a small amount of toner Tb still remains in the narrow space adjacent to the contact point between the photoreceptor 1 and the blade 8a.
That is, the toner Ta that is removed in the direction of the arrow is the toner that does not completely adhere to the contact point between the photoreceptor 1 and the blade 8a and falls from there (a), and a small amount of residual toner Tb always exists in the narrow space mentioned above. That will happen. When the cleaning is finished and the blade 8a is removed from the photoreceptor 1, this residual toner Tb moves to the side image forming area placed on the photoreceptor 1, as shown by the imaginary line, and becomes an obstacle to the next recording. Become.

Remove the toner Tb that has not been completely removed and remains adjacent to the contact point between the photoreceptor 1 and the blade 8a, and remove the toner Tb from the screw 8c.
To move the blade 8a to -, stop the rotation of the five photoconductors 10 times, separate the blade 8a from the photoconductor 1, and then move the blade 8a
This can be achieved by contacting the photoreceptor 1 before the photoreceptor 10 starts rotating. However, such an operation is extremely troublesome, especially when a plurality of recordings are performed continuously, and the drive source for rotating the photoreceptor 1 becomes cumbersome as the drive source for the blade 8a.

In addition to the above problems, conventional gluing devices have the following problems:
In particular, when one type of toner image is formed on the photoconductor every rotation of the photoconductor, and when trying to combine multiple types of toner images and transfer the toner images, the photoconductor is moved at a constant speed during one recording process. The problem is that the residual toner Ta moves to the image forming area and disturbs the brass image.

C. Purpose of the Invention The object of the present invention is to provide a cleaning device that eliminates the problems of conventional cleaning devices as described above and completely removes developer components (for example, toner) from an image bearing member. There is.

2. Structure of the Invention The present invention provides a first cleaning means on one side of the image carrier, and a second cleaning means for removing developer components remaining after cleaning by the first cleaning means. The present invention relates to a cleaning device provided on the other side of the image carrier.

E. Examples Hereinafter, the present invention will be specifically explained by examples.0 Figures 1 and 2 show the relationship between the photoreceptor and the cleaning device, and Figure 1 is taken along line I-I in Figure 2. Arrow sectional view, 2nd
The figure is a sectional view taken along the line ■--■ in FIG. In addition, the first
Components common to FIGS. 2 and 13 are designated by the same reference numerals.

An axle fixed to the side wall 1fK of the photosensitive drum 1 is rotatably attached to the side wall of the electrophotographic device via a bearing 4, and the photosensitive drum 1 is rotated in the direction of arrow J by a drive device (not shown). do. Sun gear 8 in the shaft hole
1 is fixed, a first planetary gear 82 meshes with the sun gear 81, and a second planetary gear blade meshes with the first planetary gear 82. The planetary gear wings are rotatably attached to an arm fixed to the shaft hole, and are configured to revolve around the sun gear 81 while rotating in the direction of the arrow as the shaft hole rotates.

An opening IC is provided in the drum base 1a of the photosensitive drum 1 in a direction parallel to the shaft hole, and a collecting roller fixed to the second planetary gear 83 and rotating is seen from inside the opening -1cK. The front end of the opening 1c is in sliding contact with the collecting roller 285, and the rear end of the opening 1c is attached with a valve 86 which has elasticity and slides against the collecting roller by pressing it.

A sheet photoreceptor 1b on which a selenium-based photosensitive material is vapor-deposited is wrapped around the peripheral surface of the drum base 1a, and the sheet photoreceptor 1
b has its end edge inserted into the inside of the drum base 1a through the opening 1c, and is attached with tension to the protrusion 1e provided on the inner peripheral surface of the drum base 1a via the coil spring 1d. It is installed on la. These constitute the photosensitive drum 1.

A second cleaning means 8-2 is constituted by the above-mentioned parts inside the photoreceptor drum 1 and a scraper nail, which will be described later.

A first cleaning means 8-1 similar to that shown in FIG. 13 is installed outside the photoreceptor drum 1, and a blade 8& is in sliding contact with the photoreceptor drum l rotating in the direction of arrow J. Scrape off the residual toner Ta in a circular motion. At this time, residual toner Tb remaining without being scraped off remains in the space adjacent to the contact point between the photoreceptor drum 1 and the blade 8a.
exists. The operation of the first cleaning means has already been explained, so the explanation will be omitted here.

When the photosensitive drum 1 rotates and separates from the blade 8a and the two collection rollers come into sliding contact with the blade 8a, the valve % contacts the blade 8a and separates from the collection roller &, as shown in FIG. The remaining toner Tb is removed by a rotating collection row, 7
85 and collected in the photoreceptor drum l.

Next, when the photoreceptor drum 1 further rotates and comes into sliding contact with the blade 8a, the photoreceptor drum 1 has already been completely cleaned, as shown in FIG.
The residual toner T collected in the photosensitive drum 1 by sliding contact with the
Prevent b from leaking.

Inside the photosensitive drum 1, a scraper 87 is in sliding contact with the collection roller 285, and scrapes off residual toner Tb adhering to the collection roller 285.

By configuring the cleaning device as described above,
The toner remaining on the photosensitive drum is first collected by the first cleaning means 8-1, and the remaining toner is collected by the second cleaning means 8-1, so that it does not interfere with the next recording. do not have.

Next, an example of a multicolor image forming apparatus incorporating the above-mentioned gluing device will be described.

This multicolor image forming apparatus sequentially forms yellow, magenta, cyan, and black toner images on a photoreceptor drum (hereinafter simply referred to as photoreceptor), and transfers this composite toner image onto recording paper. record a multicolor image.

During development, avoid troubles such as disturbing the toner image formed by the previous development during subsequent development, or mixing toner from the toner image developed in the previous stage into the developer of the latter stage, disrupting color balance. It uses a developing method that causes toner to fly onto the electrostatic latent image.

The principle of this multicolor image forming apparatus will be explained below with reference to the chart 7 in FIG. Figure 5 shows changes in the surface potential of the photoreceptor, taking as an example the case where the charging polarity is positive. PH indicates the exposed area of the photoconductor, DA indicates the unexposed area of the photoconductor, and DUP indicates the increase in potential due to the adhesion of positively charged toner during the first development of the exposed area PHK.

The photoreceptor is uniformly charged by a scorotron charger and has a constant positive surface potential E as shown in (a) K.

Next, first image exposure is applied using a laser, cathode ray tube, LED, etc. as an exposure source, and as shown in (b), the exposed area P
The potential of H decreases according to the amount of light. The electrostatic latent image thus formed is developed by a developing device to which a positive bias is applied such that the surface potential BK of the unexposed portion is approximately equal.

As a result, as shown in (c)K, the positively charged toner T□ adheres to the exposed area PH, which has a relatively low potential, and the first toner image T
1 is formed. The area where this toner image T1 is formed has a stain position D due to the adhesion of the positively charged toner T0.
Although only UP rises, it does not reach the same potential as the unexposed area DA. Next, the surface of the photoreceptor on which the first toner image has been formed is charged a second time by a charger, and as a result, the toner T
Regardless of the presence or absence of 8, a uniform surface potential E is obtained. This is shown in (d). A second imagewise exposure is performed on the surface of this photoreceptor to form an electrostatic latent image, and a positively charged toner image T2 of a color different from that of the toner T8 is developed in the same manner as in (e) and (e). A second toner image is obtained.
This is shown in (f). By performing the above process multiple times, a multicolor toner image is obtained on the photoreceptor. By transferring this to recording paper and fixing it by heating or pressurizing it, a υ multicolor recorded image can be obtained. In this case, the photoreceptor is cleaned of toner and charges remaining on the surface and used for the next multicolor image formation. On the other hand, apart from this, there is also a method of fixing a toner image on the photoreceptor. In the method explained in FIG. This is desirable.

In addition, in the multicolor image forming method, the second and subsequent charging steps can be omitted. When charging is repeated every time without omitting such charging, a static elimination step may be performed before charging. Furthermore, the exposure sources used for each image exposure may be the same or different.

In the multicolor image forming method, toners of four colors, for example, yellow, magenta, cyan, and black, are often superimposed on a photoreceptor for the following reasons. According to the principle of the subtractive color method, a black image should be obtained by overlapping the three primary colors of yellow, magenta, and cyan, but the toners for the three primary colors that are put into practical use have ideal absorption wavelength ranges. However, due to misalignment of the toner images of the three primary colors, it is difficult to reproduce the clear black required for characters and lines using only these three primary color toners. tends to be in short supply.
Therefore, as described above, a multicolor image is formed using four colors, which are the three primary colors plus black.

In electrophotography, image exposure means include gas or semiconductor laser light, LED, and CRT.

Liquid crystals are used.

In addition to the electrophotographic method described above, methods for forming a latent image for forming a multicolor image include a method in which an electrostatic latent image is formed by injecting charges directly onto the image forming body using a multi-needle electrode, etc. , a method of forming a magnetic latent image using a magnetic head, etc. can be used.

FIG. 6 shows an example of a device that implements this method.

In this device, a multicolor image is formed as follows.
The surface of the photoreceptor 1 as an image carrier is uniformly charged by the Scone charging electrode 2. Next, laser optical system 1
Image exposure from 0 is applied onto the photoreceptor 1. In this way, an electrostatic latent image is formed. This electrostatic latent image is developed by a developing device A containing yellow toner. The photoreceptor 1 on which the toner image has been formed is uniformly charged again by the scorotron charging electrode 2 and subjected to imagewise exposure. The formed electrostatic latent image is developed by a developing device B containing magenta toner.

As a result, a two-color toner image of yellow toner and magenta toner is formed on the photoreceptor 1.

Thereafter, the cyan toner and the black toner are developed in a similar manner, and a four-color toner image is formed on the photoreceptor 1. The four-color toner image is given a stain charge by the charging electrode 9 and is transferred onto the recording paper P by the transfer pole 4. The recording paper P is separated from the photoreceptor 1 by a separation pole 5 and fixed by a fixing device 6. On the other hand, the photoreceptor 1 is cleaned by the removing electrode 7 and the cleaning device. As described above, the cleaning device consists of the first cleaning means 8-1 and the second cleaning means 8-2.

On the other hand, since image formation cannot be performed in the aperture 1c of the photoreceptor 1,
It is necessary to form a latent image while avoiding this position. tGl is a sensor that detects the collection roller 285 peeking into the opening 1c. When the sensor 16 detects the collection roller 85, the charger 2 is activated based on this detection signal, and after a predetermined time has elapsed. The image data input section IN is now activated.

The laser optical system 10 is shown in FIG. In the figure, 120 is a semiconductor laser oscillator, part is a rotating polygon mirror, and % is an f-θ lens.

In this multicolor image forming apparatus, one color is developed each time the photoreceptor 1 rotates once, and a developing device that is not used during image formation, each electrode other than the charging electrode 2, paper feeding, paper conveyance, and cleaning means 8-1 .8-2 does not act on the photoreceptor 1.

Next, desirable developing conditions for this multicolor image forming apparatus will be explained.

As a developing device used in the multicolor image forming apparatus shown in FIG.
Four types of devices are used, which may be of the same or similar construction, and a representative cross-sectional view of the first current device A is shown in FIG. The developer Do is conveyed in the direction of arrow G by rotating the magnetic roll 41 having six N and S poles in the direction of arrow F and the sleeve 42 in the direction of arrow G. The developer De is caught in the spike control blade 43 during conveyance.
Therefore, the thickness is regulated and a developer layer is formed.
A stirring screen 5-45 is provided in the developer reservoir 6n to sufficiently stir the developer De, and when the developer De in the developer reservoir 44 is consumed, the toner supply is stopped. As the roller 46 rotates, the toner T is supplied from the toner hopper 47.

The gap between the sleeve 42 and the photoreceptor 1 is maintained so that the developer layer on the sleeve does not come into contact with the photoreceptor in a state where there is no potential difference between them. During this time, a developing bias is applied to perform reversal development. A DC power supply and an AC power supply 49 are provided in series.

On the other hand, there are two types of developers used in such machines: two-component developers consisting of toner and carrier, and one-component developers consisting only of toner.

Two-component developers require control of the amount of toner relative to the carrier, but have the advantage that the toner is easily charged (triboelectrically charged). In addition, especially in the case of a two-component developer composed of a magnetic carrier and a non-magnetic toner, it is not necessary to contain a large amount of black magnetic material in the toner particles, so it is necessary to use color toner that does not cause color turbidity due to the magnetic material. It has the advantage of being able to form clear color images.

Particularly preferable structural examples of such a two-component developer are listed below.

■Thermoplastic resin: Binder (capital) ~90. Examples: polystyrene, styrene acrylic polymer, polyester, polyvinyl butyral, epoxy resin, polyamide resin, polyethylene, ethylene vinyl acetate copolymer, etc. or mixtures of the above.

■Pigment: Coloring material 0~15wt Example: Black: Carbon Plaque Cyan: Copper 7-talocyanine, sulfonamide dielectric dye Yellow: benzidine derivative Magenta: Rhodamine B Lake, Carmine 6B, etc.

■Charge control agent 0-5wtts Positive donor: Nigrosine-based electron-donating dye, alkoxylated amine, alkylamide, chelate, pigment, quaternary ammonium salt, etc.

Minus toner: Electron-accepting organic complex, chlorinated paraffin, chlorinated polyester, polyester with excess acid groups, chlorinated copper phthalocyanine, etc.

, ■ Examples of fluidizing agents:; rhoidal silica, hydrophobic silica, silicon face, metal soap, nonionic surfactants, etc.

■Cleaning agent (prevents toner filming on the photoconductor) Examples: fatty acid metal salts, silicon oxides with organic groups on the surface,
Fluorine surfactants, etc.

■Fillers (Aimed at improving the surface gloss of images and reducing raw material costs.) Examples: calcium carbonate, clay, talc, pigments, etc.

In addition to these materials, a magnetic material may be included to prevent fogging and toner scattering.

Examples of the magnetic powder include triiron tetroxide, r-ferric oxide, chromium dioxide, nickel 7-elite, iron alloy powder, etc., each having a diameter of 0.1 to 1 μm, and are contained in an amount of 5 to 70 wtes based on the toner. The resistance of the toner varies slightly depending on the type and amount of magnetic powder, but in order to obtain a sufficient resistance of 10 8 Ω, preferably 10 12 Ω or more, the amount of magnetic material is preferably 55 wt % or less.

In addition, in order to maintain clear colors as a color toner,
It is desirable that the amount of magnetic material be 30wtl5 or less.
Other resins suitable for pressure fixing toner include approximately 20
Adhesive resins such as wax, polyolefins, ethylene-vinyl acetate copolymers, polyurethane, and rubber are selected so that they can be plastically deformed and adhered to paper with a force of about kg/cm. Capsule toners can also be used.

A toner can be produced using the above-mentioned materials by a conventionally known production method.

In the structure of the present invention, in order to obtain a more preferable image, it is preferable that the weight average particle size of these toner particles is generally about 1.5 μm or less in view of the relationship with resolution. In this method, there is no theoretical limit to the toner particle size, but from the viewpoint of resolution, toner scattering, and conveyance, it is usually preferably about 1 to 30 μm.

The weight average particle diameter as used herein is a value measured with a Coulter Counter (manufactured by Coulter Inc.).

Carrier Basically, the materials listed as the toner constituent materials are used. In order to improve fine points, lines, or gradation, the carrier particles are particles composed of magnetic particles and resin, such as a resin dispersion system of magnetic powder and resin, or resin-coated magnetic particles, and more preferably spherical particles. The weight average particle diameter is preferably less than μm, particularly preferably I μm.
Particles with a diameter of 5 μm or less are suitable. In this example, carrier particles having a weight average particle diameter of μm were used for all four colors.

In addition, in order to solve the problem that the bias voltage is injected into the carrier particles and the carrier tends to adhere to the photoreceptor surface, the resistivity of the carrier is set to 108Ω or more. Preferably, the insulating material has a resistivity of 1013 ohms or more, more preferably 1014 ohms or more, and the particle size is preferably as described above. Using the magnetic material and thermoplastic resin described above, the surface of the magnetic material is coated with resin, or particles are made of resin containing dispersed magnetic particles, and the resulting particles are It is obtained by particle size selection using a particle size selection means.

Furthermore, the carrier is made spherical in order to thoroughly stir the toner and carrier, improve the fluidity of the developer, and sufficiently charge the toner to prevent agglomeration of toner particles and toner particles and carrier particles. It is desirable to do so.
For spherical magnetic carrier particles, for resin-coated carrier particles, select spherical magnetic particles as much as possible and apply resin coating treatment to them; for carriers with magnetic fine particle dispersion, use magnetic fine particles as much as possible. , performing spheroidization treatment with hot air or hot water after forming dispersed resin particles;
Alternatively, it can be manufactured by directly forming spherical dispersed resin particles using a spray drying method. Note that the specific resistance of toner and carrier is measured by the following measurement method. That is, after the particles were placed in a container with a cross-sectional area of 0.50 m and tapped, 1# was placed on the packed particles.
Apply a load of 10" to 1" between the load and the bottom electrode.
It is determined by applying a voltage that generates an electric field of 0' V/ctm, reading the current value flowing at that time, and performing a predetermined calculation. At this time, the thickness of the carrier particles is approximately 1 nm.

Next, the developing method will be explained. For development, a method of direct rubbing with a magnetic pusher may be used, but especially after the second development, to avoid damage to the formed toner image, it is necessary to use It is desirable to use a non-contact development method in which the developer layer does not rub against the surface of the photoreceptor. This non-contact method forms an alternating electric field in the developing area and performs development without rubbing the photoreceptor and the developer layer. This will be explained in detail below.

In repeated development using an alternating electric field as described above, it is possible to repeat the development several times on a photoreceptor on which a toner image has already been formed, but if appropriate development conditions are not set, during subsequent development, When the toner image formed on the photoconductor in the previous stage is disturbed, the toner already attached to the photoconductor returns to the developer conveying body, which stores a developer of a different color from the developer in the previous stage. A phenomenon occurs in which the particles invade the developing device in the subsequent stage. Basically, to prevent this, the developer layer on the developer transporting member should be operated without rubbing or contacting the photoreceptor. For this purpose, the gap between the image carrier and the developer transporting member is kept larger than the thickness of the developer layer on the developer transporting member (provided that there is no potential difference between them). The inventor's experiments have revealed that there are desirable development conditions in order to completely avoid the above-mentioned problems and to form each toner image with sufficient image density. The conditions are the gap d (II) (hereinafter sometimes simply referred to as gap d) between the image bearing member and the developer transport body in the development area, the amplitude vAo and the frequency f ( It is difficult to obtain an excellent image even if the value of H2) is determined independently, and these parameters are closely related to each other.The process will be explained below.

The experiment was conducted using the multicolor image forming apparatus shown in FIG.
When forming two-color toner images with developing devices A and B, the influence of parameters such as the voltage and frequency of the alternating current component of the developing bias of developing device B was investigated.

Development is performed using developing devices A and B in this order.

The developer De initially stored in the developing device B is a one-component magnetic developer containing 70 wt % of a thermoplastic resin and a pigment (
Carbon black) 10wt%, magnetic material 20wt%, and a charge control agent are cross-milled to give an average particle size of 15 μm, and a fluidizing agent such as silica is added.The amount of zero charge is controlled by the charge control agent.

After conducting the experiment while changing the above conditions, we were able to organize the relationship between the amplitude of the AC electric field strength and the frequency, and the 9th
The results shown in the figure were obtained. Note that the electric field here is a nine value obtained by dividing the bias voltage by the gap d.

In FIG. 9, the areas marked with ■ are areas where uneven development is likely to occur, the areas marked with ■ are areas where the effect of the alternating current component does not appear, and the areas marked with ■ are areas where destruction of the already formed toner image occurs. The easy-to-bleach region (■■) is a region where the effect of the alternating current component appears, a sufficient development density is obtained, and the already formed toner image is not destroyed, and [F] is a particularly preferred region.

Based on the above experimental results, the present inventor set the amplitude of the AC component of the developing bias to VAC (V), the frequency to f (Hz), and the gap between the photoreceptor 1 and the sleeve 42 to d (lu
If development is performed under the conditions that satisfy 0.2≦VAC/(d@f)≦1.6 when It was concluded that this can be done at appropriate concentrations. In order to obtain sufficient image density and not disturb the toner image formed up to the previous stage, 0.4≦VAC/(d@f)≦
It is highly desirable to satisfy the conditions 1.2. Further, within this region, it is more desirable that the region where the electric field is slightly low enough to saturate the image density satisfies 0.6≦vAc/(dllf)≦1.0.

In addition, in order to prevent uneven development due to the AC component, the frequency f of the AC component is set to 200 Hz or more, and the developer is applied to the photoreceptor 1.
When a rotating magnetic roll is used as a means for supplying the fluid, the frequency of the AC component is set to 500 Hz in order to eliminate the influence of the AC component and the surface distortion caused by the rotation of the magnetic roll.
In addition to the above, an experiment was conducted using the multicolor image forming apparatus shown in FIG.

The developer De stored in the developing device B is a two-component developer consisting of a magnetic carrier and a non-magnetic toner. This is a carrier created by dispersing fine iron oxide in a resin.

The toner was prepared by adding a small amount of a charge control agent to 90 wt 1 of a thermoplastic resin, 10 wt % of a pigment (carbon black), and cross-milling the mixture to obtain an average particle size of 10 μm.

The horse chestnut was mixed with 80 wt % of the carrier at a ratio of 20 wt % to form a developer Do. Note that the toner is negatively charged due to friction with the carrier. In addition, developing device B
contains a two-component yellow developer. Developing is performed using developing devices A and H in this order.

When the experiment was conducted while changing the above conditions, the relationship between the amplitude of the alternating current electric field strength and the frequency f could be sorted out, and the results shown in FIG. 10 were obtained.

In FIG. 10, the area indicated by ■ is an area where uneven development is likely to occur, the area indicated by ■ is an area where the effect of the alternating current component does not appear, and the area indicated by ■ is an area where the toner 6-6 is already formed.
Areas where image destruction is likely to occur, ■ and ■ are areas where the effect of the alternating current component appears and sufficient development density is obtained, and destruction of the already formed toner image does not occur, and ■ is a particularly preferable area. 0 Based on the above experimental results, the inventor set the amplitude of the AC component of the developing bias to vAc (v), the frequency to f (Hz), and the gap between the photoreceptor 1 and the sleeve 42 to d (w) in each developing process.
If development is performed under the conditions satisfying 0.2≦VAC/(d-f) ((vAc/d)-1500)15≦1.0, the toner already formed on the photoreceptor 1 will be removed. It was concluded that subsequent development could be carried out at appropriate density without disturbing the image. In order to obtain sufficient image density and not disturb the toner image formed up to the previous stage, 0.5≦VAC/(a-f) ((VAC/d)-1500)/5≦1.0. It is preferable to meet the requirements. Furthermore, among these, 0.5≦vAc (d II S ) ((VAC/d) −1500) 15 ≦0.
If 8 is satisfied, a clear multicolor image without color turbidity will be obtained, and even if the developing device is operated many times, it will be possible to prevent toner of a different color from entering the developing device.0 Also, uneven development due to alternating current components will be prevented. Therefore, the frequency of the AC component is 200H as in the case of using a component developer.
z or more, and as a means for supplying the developer to the photoreceptor 1,
When using a rotating magnetic roll, in order to eliminate the influence of the eel caused by the alternating current component and the rotation of the magnetic roll,
As a result of experiments, it became clear that the frequency of the AC component should be 500 Hz or higher.

The image forming process according to the present invention is as exemplified above, but without destroying the toner image formed on the photoreceptor 1, successive toner images are developed on the photoreceptor 1 at a constant density. (1) Use toners with increasing charge levels as the development process is repeated.

■ Gradually reduce the amplitude of the electric field strength of the AC component of the developing bias.

■ Sequentially increase the frequency of the AC component of the developing bias.

It is more preferable to employ these methods alone or in any combination.

That is, toner particles with a larger amount of charge are more easily affected by the electric field. Therefore, if highly charged toner particles adhere to the photoreceptor l during initial development, these toner particles may return to the sleeve during subsequent development. Therefore, the above-mentioned point (2) is to prevent the toner particles from returning to the sleeve during the subsequent development by using toner particles with a small amount of charge in the initial development. (i) As development is repeated (i.e., as development progresses to later stages)
In this method, the electric field strength is gradually reduced to prevent the toner particles already attached to the photoreceptor from returning. Specific methods for reducing the electric field strength include a method in which the voltage of the alternating current component is gradually lowered, and a method in which the gap d between the photoreceptor 1 and the sleeve edge is made wider as the developing stage progresses.

In addition, the above-mentioned method (2) is a method of preventing the toner particles already attached to the photoreceptor 1 from returning by increasing the frequency of the alternating current component sequentially as development is repeated.

These ■■■ are effective when used alone, but they are even more effective when used in combination, for example, by sequentially increasing the toner charge amount and gradually decreasing the alternating current bias as development is repeated. Furthermore, when the above three methods are adopted, appropriate image density or color balance can be maintained by adjusting the DC biases respectively.

Based on the above findings, specific recording conditions were set as follows, and a large number of continuous multicolor images were formed according to the time chart shown in FIG. In FIG. 11, the filters in the reading section are replaced in the order of blue, green, red, and ND (neutral density) every round trip.

Image forming conditions Image forming body photosensitive layer Se Drum diameter 120 fl Linear speed 250 w/sec Surface potential Development conditions Between photoreceptor and sleeve 1.0 sm Development bias A (Y) DC700V ACiff 2
KHzB (M) DC700V ACiff 2KH
iC (C) DC700V AC1172KHzD (K
) DC700V ACiff 2KHz non-current condition sleeve, magnetic roll is stopped and via x
Let ACo, 31ft or less, DCOv.

Other four-process transfer Corona fixing Heat roller Cleaning As a result, even during continuous recording, stable, high-quality, full-color recorded images faithful to the original were always obtained.

As described in detail, the IJ-ing device based on the present invention includes a first cleaning means on one side of the image carrier.
Since the second cleaning means is provided on the other side, the remaining developer component that has not been completely cleaned by the first cleaning means is removed by the second cleaning means, and the developer remaining on the counter-pressing member is removed. Since there are no components at all, there is no problem with subsequent image formation.

[Brief explanation of drawings]

1 to 11 show embodiments of the present invention, and FIGS. 1 to 4 show the relationship between the photoreceptor and the cleaning device, and FIG. 1 is I-I in FIG. Fig. 2 is a sectional view taken along the line ■-■ of Fig. 1, showing the first cleaning means in operation, and Fig. 3 shows the second cleaning means in operation. Figure 5 is a flowchart showing the multicolor image forming process, Figure 6 is a schematic diagram of the multicolor image forming device, Figure 7 is a schematic diagram of the laser optical system, and Figure 8 is a diagram of the developing device. 9 and 10 are graphs showing the optimum conditions for development, and FIG. 11 is a time chart showing the continuous image forming process of the multicolor image forming apparatus. 12 and 13 show a conventional example, in which FIG. 12 is a schematic diagram of an image forming device, and FIG. 13 is a sectional view of a cleaning device. In addition, in the symbols shown in the drawings, 1......Photoconductor 1c......Aperture a of photoconductor, A,
B, C, D......Developing device 8-1.
......First cleaning means 8-2
......Second cleaning means 8a
・・・・・・・・・・・・Cleaning blade 8b・
・・・・・・・・・ Spongebob 28c・・・・・・
・・・・・・Screw 81・・・・・・・・・・・・
・Sun gear 81.82・・・・・・・・・Planetary gear blade・・・・・・Collection roller 10・・・・
......Laser optical system 16...
・・・・Sensor L・・・・High exposure IN・・・Image data input section TR・
...... Image data processing section.

Claims (1)

[Claims] 1. A first cleaning means is provided on one surface of the image carrier, and a second cleaning means for removing developer components remaining after cleaning by the first cleaning means is provided on the other surface of the image carrier. Cleaning equipment in preparation for.