JP3205617B2 - Image forming method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus based on an electrophotographic process applied to a printer, a facsimile, a copying machine, and the like. The present invention relates to an image forming method for performing development almost simultaneously with exposure while exposing a photoreceptor by exposure means.

[0002]

2. Description of the Related Art Conventionally, respective process means of exposure, development, transfer, cleaning (removal of residual toner), charge elimination and charging are arranged on an outer peripheral surface of a photosensitive drum, and an image is formed by a predetermined electrophotographic process. Electrophotographic devices based on the so-called Carlson process for performing are well known. According to such an apparatus, the process means must be independently disposed on the outer peripheral surface of the photosensitive drum, and a high voltage is required not only for charging but also for developing bias. Is complicated and large. In order to solve such a defect, for example, a photoconductive drum is formed by laminating a light-transmitting conductive layer and a photoconductor layer on a cylindrical light-transmitting support, and a photoconductor drum corresponding to image information is formed in the drum. Exposure means for generating a light output is inserted, and the light output of the exposure means is confronted with the photosensitive drum at the same time as or immediately after the latent image is formed (exposed) on the photoconductor layer through a focusing lens. An image forming apparatus (see Japanese Patent Application Laid-Open No. 58-108) configured to convert the latent image into a toner image (development) via a toner carrier and transfer the toner image to recording paper via a transfer roller or other transfer means. No. 153957) has been proposed.

Therefore, it is premised that the toner used in the above-mentioned apparatus is a conductive toner in order to inject electric charge from the developing sleeve side. However, if the conductive toner is used, the static toner due to corona discharge like the insulating toner is used. It is not possible to use an electrotransfer unit. Therefore, in general, a transfer roller is used, and a transfer bias, heat or a magnetic force is applied to the transfer roller to increase the transfer efficiency. The value tends to fluctuate due to humidity and other environmental factors, so that stable and smooth transfer could not be performed, and it was difficult to form a high-quality image.

In order to solve such a drawback, the inventor of the present invention is similar to the prior art in that a two-component developer composed of a combination of a high-resistance or insulating toner and a conductive carrier is used. A developer in which a conductive carrier is formed by fixing conductive fine particles on the surface of particles in which a magnetic substance is dispersed in a binder resin (Japanese Patent Application No. 3-280870).
No.). However, since the resin carrier fixes the conductive fine particles on the surface of the binder, the fine particles are peeled off over a long period of use, and the developer is likely to deteriorate.

Therefore, the present inventor has proposed using a three-component developer in which a high-resistance or insulating carrier is mixed together with the conductive resin carrier in the prior application technology.
(Japanese Patent Application No. 4-10513) By adding a high-resistance carrier, the carrier and the insulating toner are electrostatically attracted, and the toner is attracted around the high-resistance carrier.
As a result, the amount of the insulating toner around the conductive carrier decreases, and the probability of contact between the conductive carriers increases. As a result, even if the conductive fine particles adhered to the surface of the conductive resin carrier are peeled and damaged, the probability of contact between the conductive carriers is high, so that an electrical conduction path can be easily secured, and the conductive carrier can be maintained for a long time. Therefore, a stable resistance value can be obtained.

[0006]

Therefore, the above-mentioned three-component developer can hold the insulating toner by the electrostatic force of the high-resistance carrier, so that the toner can be carried on the developing sleeve even if the toner itself does not have magnetic force. As a result, it is possible to convey to the photosensitive member side, and as a result, a path for use as a color toner and application of the present apparatus as a color image apparatus is opened.
That is, if a magnetic component is mixed in the toner, the magnetic material itself is generally non-transparent, so that a clear color cannot be obtained,
In the case of a color toner, a transparent magnetic powder such as YIG can be used. However, since such a magnetic powder is expensive, it is not advisable to use it as a consumable toner. Is based on the premise that non-magnetic toner can be used.

However, when a non-magnetic toner is used, the toner is only charged and held by the contact charging of the high-resistance carrier, so that the conveying force and the holding force are weaker than the magnetic attraction force. The device applied to the present invention is the above-described developer reservoir, in which the non-magnetic toner is charged with an electrostatic holding force in order to perform charging exposure while performing stirring by the relative peripheral speed ratio between the developing sleeve and the photosensitive drum. Therefore, the toner adheres also to the background portion of the photoreceptor due to rubbing with the photoreceptor drum, so that a so-called fog occurs.

In view of the drawbacks of the prior art, an object of the present invention is to provide an image forming method capable of forming a clear image without fogging even when a non-magnetic toner is used as described above.

[0009]

According to the present invention, an exposure means is disposed on the back side of a photosensitive drum facing a developing sleeve, and a developer rubbing area formed between the developing sleeve and the photosensitive drum is provided. After charging the photoreceptor while applying a developing bias, in an image forming method of performing development almost simultaneously with or immediately after exposure, in the developer, one or more magnetic carriers including at least a conductive magnetic carrier, It is essential to use a developer made of a high-resistance or insulating non-magnetic toner and to set the developing bias at a minimum potential level equal to or higher than the photoconductor exposure potential with a vibration waveform substantially centered on the photoconductor charging potential. And

[0010] The first feature of the present invention, and one or more of the magnetic carrier as described above, the developer comprising a high-resistance or insulating non-magnetic toner (hereinafter referred to as toner), and more specifically the the plurality of magnetic carrier means and conductive magnetic carrier, a high-resistance or insulating magnetic carrier (hereinafter referred to as high-resistance carrier), their calibration
Rear and a developer made of a high-resistance or insulating non-magnetic toner, and a developing bias applied between the developing sleeve and the photosensitive drum via a developer rubbing region is applied with a developing potential centered on a substantially photosensitive member charging potential. In some cases, a vibration waveform bias whose minimum potential level is equal to or higher than the exposure potential of the photoconductor is used.

In this case, since the charging potential level is set according to the central potential level of the developing bias, the two almost coincide with each other. However, they do not always completely coincide with each other due to a slight voltage drop due to the developer. Such a vibration waveform bias is formed by superimposing an alternating current (Sin wave), a triangular wave, and a rectangular wave on a direct current corresponding to a charging potential level, but is preferably formed of a rectangular waveform component. The above-mentioned conductivity has a resistance value of 10 ⁶ Ω · cm or less, preferably 10 ⁴ Ω · cm or less, and the high resistance or insulation has a resistance value of 10 ⁹ Ω · cm or more, preferably 10 ⁹ Ω · cm or more.
Refers to those of ¹¹ Ω · cm or more.

Also, a second feature of the present invention is that the frequency of the vibration waveform bias is 50 Hz or more and 750 Hz
Or the amplitude of the vibration waveform bias is set within a range of ± 15% to ± 60% around the photoconductor charging potential, or the weight ratio between the plurality of carriers and the toner is set to It is also an effective means of the present invention to set the number of carriers to four or more or to set the peripheral speed of the developing sleeve higher than the peripheral speed of the photosensitive drum.

Further, in the present invention, it is preferable that the frequency of the vibration waveform bias is set to be not less than 50 Hz and not more than 750 Hz. The following may be set. Hmin = 1 / (Nw / Sd) 1) Hmin = minimum frequency of developing bias Sd = peripheral speed of photosensitive drum (cm / S) Nw = downstream from the exposure position of the developer rubbing area in the drum rotation direction Nip width (cm)

[0014]

In the case of this apparatus, in order to adopt a reversal developing method in which toner adheres to the exposed portion of the photoreceptor, the background portion has the charged potential and the image portion has the exposed potential. For example, the force acting on the toner at the time of development is as follows: electrostatic force: Fe, magnetic force: Fm, mechanical force:
When F and the centrifugal force: Fr, the electrostatic force: Fe is ideally 0 in the background portion, but can be approached to 0 by bringing the charging series of the toner and the photoconductor closer. When Fe + Fr <Fm + F, the toner does not transfer to the photoreceptor side. However, when non-magnetic toner is used, Fm = 0. Therefore, when the peripheral speed of the developing sleeve is considerably higher than the peripheral speed of the photoreceptor drum, Due to the centrifugal force generated by the peripheral speed difference (because the mechanical force F is so small that it can be ignored), there is a large possibility that the toner is transferred to the background portion. In this case, in the case of the Carlson type electrophotography in the background portion, by setting the developing bias Vb to | Sp |> | Vb | with respect to the surface potential Sp of the background portion, the toner adhering to the background portion is set. The fogging can be prevented by applying an electric field force Fn that pulls back the toner. However, as in the present apparatus, a developing bias is applied through a developer rubbing area formed between the developing sleeve and the photosensitive drum. In the method of charging the photosensitive member while charging, the charging potential is set by the developing bias potential, and there is a slight voltage drop due to the developer.
> | Vb | cannot be set.

Therefore, the present invention instantaneously realizes the above equation by superimposing an oscillation waveform on a DC bias having a potential level corresponding to the charged potential, as described above, and reduces fog. In this case, since the lowest potential level of the vibration waveform is equal to or higher than the exposure potential of the photoreceptor, there is no room for pulling back in the image portion, thereby enabling formation of a clear image without lowering the image density.

The vibration waveform includes a sine wave, a triangular wave, a rectangular wave, and a pulse wave having an amplitude between a ground potential and a sine wave or a triangular wave. The upper end of the potential is a point, which is sufficient for the toner to move. Since the electric field does not reach a high level, it is effective but not sufficient. In addition, the pulse wave cannot supply a sufficient amount of charge required for charging, and the image definition deteriorates. In the case of using a rectangular wave, the toner adhered to the background portion is vibrated by the centrifugal force Fr to impart a reverse transition while vibrating, and it is possible to smoothly prevent the occurrence of fogging.

The frequency of the vibration waveform bias used in the present invention may be set to a value equal to or higher than the expression 1) and equal to or lower than 1000 Hz, but is preferably set to 50 to 750 Hz. That is, if the bias does not make at least one reciprocation on the nip width downstream of the exposure position in the drum rotation direction, vibration cannot be given, and horizontal stripes or the like are generated on the photoconductor side by one-way transfer or reverse transfer. Would. Conversely, as will be apparent from the experimental results described later, the effect of the present invention starts to decrease from the above-mentioned frequency of 600 Hz or more. When the frequency becomes 1000 Hz or more, a pulse width sufficient for the toner to oscillate cannot be obtained. This is similar to the application of a bias, and cannot prevent the occurrence of fog. Therefore, the frequency is preferably about 50 to 750 Hz, though it depends on the peripheral speed of the photosensitive drum.

If the amplitude of the vibration waveform bias is too small, only the same effect as that of the DC bias can be obtained. If the amplitude is too large, charging is not sufficiently performed, and the image definition deteriorates. Therefore, in the present invention, it is preferable that the amplitude is set within a range of ± 15% to ± 60% around the photoconductor charging potential. In the present invention, it is preferable that only the toner be reciprocally oscillated by the bias. Therefore, in the present invention, both the carriers are magnetic carriers, and the weight ratio of the toner to the toner is 4 to 4. It is better to set above. That is, by forming both carriers from a magnetic material, it is possible to obtain a magnetic coercive force on the developing sleeve side, thereby preventing both carriers from adhering to the photoreceptor side and reducing the weight ratio with the toner to 1%. : By setting the ratio to 4 or more, an adhesion preventing effect can be further obtained.

[0019]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of the present invention; However, unless otherwise specified, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention, but are merely illustrative examples. Not just. FIG.
1 is a schematic diagram illustrating a configuration of a printer according to an embodiment of the present invention. Reference numeral 1 denotes a photosensitive drum in which the LED unit 2 is inserted, and a developing sleeve 30 and a transfer roller 4 incorporated in the developing unit 3 are arranged along the rotation direction of the photosensitive drum.
From the upstream side along the tangential direction between the photosensitive drum 1 and the transfer roller 4, a paper feed cassette 5, a paper detection sensor 6, a registration roller 7, and a fixing roller 8 sandwiching the transfer roller 4.
Are arranged. The transfer roller 4 uses a conductive roller to increase the transfer efficiency, applies a transfer bias having a polarity opposite to the charging potential of the toner, and uniformly presses the peripheral surface of the photoreceptor drum 1. It is configured to be rotatable in synchronization with

Next, the configuration of the photosensitive drum 1 and the developing unit 3 which are main parts of the present invention will be described in detail. The photosensitive drum 1 is formed by laminating a light-transmitting conductive layer 1b, an injection blocking layer 1e, a photoconductor layer 1c, and a surface layer 1f on a light-transmitting support 1a from the inner surface side. In the example, the outer diameter is set to 30 mm, and the translucent conductive layer 1b is grounded.

The LED units 2 inserted in the photosensitive drum 1 are LEs arranged in a line along the axial direction of the drum.
It comprises a converging lens array 23 (trade name: Selfoc lens) disposed on a printed circuit board on which a D chip array 21 and the like are mounted.
4 holds. The LED unit 3 deflects the exposure position slightly to the downstream of the drum 1 rotation direction from the closest point of the drum / sleeve, in other words, the center line connecting the photosensitive drum 1 and the axis of the developing sleeve 30. 1 to form an image on the photoconductor layer 1c.

The developing unit 3 comprises a toner supply container 32 and a developing container 31 containing a carrier and toner.
A developing sleeve 30 containing a fixed magnet assembly 33 is disposed on the side of the container 31 facing the photoconductor drum 1, and the diameter of the sleeve 30 is set to 3 similarly to the photoconductor drum 1.
While being set to 0φ, the photosensitive drum 1 is rotated counterclockwise in the opposite direction to the photosensitive drum 1 so as to be capable of forward feeding at the developing position. Further, the developing sleeve 30 is configured to be capable of applying a developing bias Vi in which a vibration waveform component is superimposed on a DC voltage, as described later. Fixed magnet assembly 33 is set to a magnetic pole arrangement as shown in FIG. 1, a main magnetic pole for forming a sliding Kosuiki 10 in Japanese N1 is slightly drum rotation direction upstream side from the closest position between the drum / sleeve 30 It is arranged at the position displaced to. On the other hand, the developing container 31 has an opening on the lower peripheral surface side of the developing sleeve 30 facing the photosensitive drum 1, and both sides of the opening are concavely formed in an arc shape.
The photosensitive drum 1 is accommodated and arranged in the recessed portion, and the transfer roller 4 is brought into rolling contact with the drum bottom surface. In the figure, 35 is a toner supply roller, 34a is a slit opening,
6 is a density control sensor, and 37 is a stirring roller.

Next, the composition of the developer used in the developing unit 3 will be described. In the present embodiment, as described above, a conductive magnetic carrier, a high-resistance magnetic carrier,
It consists of three components of high resistance toner. Here, as the conductive magnetic carrier, a carrier in which conductive fine particles are fixed on the surface of carrier base particles in which a magnetic substance is uniformly dispersed in polyethylene or another binder resin is used, and the average particle size of the carrier is 30 μm. , The specific gravity is 2.70, and the volume resistivity is 10 ¹ to 10 ⁶ Ω · cm, specifically 10
Those having a resistance of ³ Ω · cm are used. For the high-resistance magnetic carrier, a carrier in which a magnetic material is uniformly dispersed in a phenol resin or other binder resin is used, the average particle size of the carrier is set to 60 μm, the specific gravity is 1.82, and the volume resistivity is 10 ¹¹ Ω · cm or more, for example, 10 ¹³
・ Ω · cm is used. Furthermore, for high-resistance non-magnetic toner, a charge control agent and the like are uniformly kneaded together with a pigment (quinacridone pigment for magenta, phthalocyanine pigment for cyan, azo or disazo pigment for yellow) in a polyester resin, and crushed and classified. The average particle size of the toner is set to 10 μm, the specific gravity is 1.25, and the volume resistivity is 10 ¹¹ Ω · cm or more, for example, 10 ¹³ Ω · cm. Then, the carrier and the toner are mixed to form a developer. In this embodiment, in particular, the mixing ratio of high-resistance non-magnetic toner / high-resistance magnetic carrier / conductive carrier is set to 10% / 10% /
It is set to 80%. The weight ratio of the toner to the respective carrier was 1: 6.6 (toner / high-resistance magnetic carrier) and 1: 8.6 (toner / conductive carrier), respectively, and was 1: 4 or more.

In such an apparatus, the developing sleeve 30
A state in which the peripheral speed of the (diameter 30 mm) is controlled to be 228 mm / s, and the peripheral speed of the photosensitive drum 1 (diameter 30 mm) is controlled to be 38 mm / s (peripheral speed ratio 6: 1, peripheral speed difference 420 mm / s).
When the nip width of the developer rubbing area formed between the drum 1 and the sleeve 30 was examined, the total nip width was 5
The nip width on the downstream side in the drum rotation direction from the exposure position of the rubbing area was about 2 to 3 mm.

Next, a frequency of 10 is applied to the developing sleeve of the apparatus.
0Hz, square wave with amplitude 50 ± 20v, frequency 100H
Sine wave with amplitude of 50 ± 20v at z, frequency 100Hz
And a triangular wave with an amplitude of 50 ± 20v and a frequency of 100Hz
FIG. 2 is a graph showing the state of fogging by applying a developing bias composed of a ground pulse wave having an amplitude of 50 to 0 V. As can be seen from the figure, the rectangular wave developing bias has the best fog reduction effect, and the sine wave and the triangular wave are not satisfactory, but a predetermined fog reduction effect is obtained. However, in the case of the pulse wave, the charging potential also decreased, and therefore, there was almost no fog reduction effect along with the decrease in print density.

Next, FIG. 3 is a graph showing the fog situation while changing the frequency of the rectangular wave having an amplitude of 50 ± 20 V. As is clear from this drawing, 100 to 550H
The developing bias before and after z has the best fog reduction effect. Conversely, when the frequency becomes 550 Hz or more, the fogging reduction effect gradually decreases. Can not be prevented. Further, when the frequency is reduced to 100 Hz or less, the fogging reduction effect is sharply reduced to 20 Hz.
In the following, horizontal streaks and the like occur on the photoconductor side. Therefore, the peripheral speed Sd of the photosensitive drum is 38 mm / S, and the nip width Nw downstream of the exposure position in the drum rotation direction is 2-3 mm.
At least, the vibration waveform bias used in the present invention has a frequency equal to or higher than the above-mentioned formula 1) and 10
It can be understood that the frequency is preferably set to 00 Hz or less, preferably 50 to 750 Hz.

Next, the amplitude of the rectangular wave having a frequency of 100 Hz is set to 1
FIG. 4 is a graph showing the situation of fogging while changing in units of 0 v. As apparent from this figure, ± 10 V to ± 10 V
A developing bias of 30 V, especially around ± 20 V has the best fog reduction effect, and conversely, ± 10 V or less or ± 20 V or less.
At 30v or more, the fog reduction effect gradually decreases, and ± 0v
(DC bias) or more than ± 40 V cannot prevent fogging. Therefore, in the present invention, the amplitude is set to ± 15% to ± 15% around the photoconductor charging potential.
It is understood that it is better to be within the range of 60%.

Although the present invention has been described with reference to the embodiment in which a vibration waveform bias is applied to a three-component developer, it is clear from the present description that the two components of a high-resistance non-magnetic toner and a conductive magnetic carrier are used. The same effects as described above can be obtained by applying a vibration waveform bias to the system developer. That is, if the toner is a conductive magnetic carrier capable of performing a certain amount of triboelectric charging, a clear image can be obtained without fogging due to the vibration waveform bias.

[0029]

As described above, according to the present invention, there is provided an image forming method in which an exposing means is provided inside a drum-shaped or belt-shaped photoreceptor, and the photoreceptor is exposed by the exposing means and development is performed almost simultaneously with exposure. Even when a non-magnetic toner is used, a clear image can be formed without fogging, thereby facilitating the application of the present apparatus to colorization. And so on.

[Brief description of the drawings]

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

FIG. 2 is a relationship diagram showing a relationship between various waveform components and a fogging situation.

FIG. 3 is a relationship diagram showing the relationship between the frequency Toka yellowtail situation

FIG. 4 is a relationship diagram showing a relationship between the amplitude of a waveform component and a fogging situation.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Photoconductor 2 Exposure means 30 Developer conveyance body (developing sleeve) 10 Developer rubbing area

Claims (7)

(57) [Claims] (1)The photosensitive drum facing the developing sleeve
An exposure means is arranged on the back side, and the developing
Through the developer rubbing area formed between the photosensitive drum and the photosensitive drum.
After charging the photoconductor while applying the image bias,
An image forming method that develops almost simultaneously with or immediately after light
In the law, The developer contains at least a conductive magnetic carrier.
Means multiple magnetic carriers and high resistance or insulating non-magnetic
A developer made of toner is used, and the developing via is used.
The oscillation waveform is a vibration waveform centered on the photoconductor charging potential.
If the minimum potential level is set higher than the photoconductor exposure potential
In the meantime, The frequency of the vibration waveform bias is equal to or more than the following expression 1) and
Image forming method characterized by being at 1000 Hz or less
Law. Hmin = 1 / (Nw / Sd) 1) Hmin = minimum frequency of developing bias Sd = peripheral speed of photosensitive drum (cm / S) Nw = downstream in the drum rotation direction from the exposure position in the developer rubbing area
Nip width at side (cm) (2)The photosensitive drum facing the developing sleeve
An exposure means is arranged on the back side, and the developing
Through the developer rubbing area formed between the photosensitive drum and the photosensitive drum.
After charging the photoconductor while applying the image bias,
An image forming method that develops almost simultaneously with or immediately after light
In the law, The developer contains at least a conductive magnetic carrier.
Means multiple magnetic carriers and high resistance or insulating non-magnetic
A developer made of toner is used, and the developing via is used.
The oscillation waveform is a vibration waveform centered on the photoconductor charging potential.
If the minimum potential level is set higher than the photoconductor exposure potential
In the meantime, The oscillation waveform bias is substantially shifted around the charging potential.
An image characterized by a returning rectangular waveform bias
Forming method. (3)The photosensitive drum facing the developing sleeve
An exposure means is arranged on the back side, and the developing
Through the developer rubbing area formed between the photosensitive drum and the photosensitive drum.
After charging the photoconductor while applying the image bias,
Almost simultaneously with light Or an image forming method that develops immediately after
In the law, The developer contains at least a conductive magnetic carrier.
Means multiple magnetic carriers and high resistance or insulating non-magnetic
A developer made of toner is used, and the developing via is used.
The oscillation waveform is a vibration waveform centered on the photoconductor charging potential.
If the minimum potential level is set higher than the photoconductor exposure potential
In the meantime, The frequency of the vibration waveform bias is 50 Hz or more;
An image forming method, wherein the frequency is 750 Hz or less. (4)The photosensitive drum facing the developing sleeve
An exposure means is arranged on the back side, and the developing
Through the developer rubbing area formed between the photosensitive drum and the photosensitive drum.
After charging the photoconductor while applying the image bias,
An image forming method that develops almost simultaneously with or immediately after light
In the law, The developer contains at least a conductive magnetic carrier.
Means multiple magnetic carriers and high resistance or insulating non-magnetic
A developer made of toner is used, and the developing via is used.
The oscillation waveform is a vibration waveform centered on the photoconductor charging potential.
If the minimum potential level is set higher than the photoconductor exposure potential
In the meantime, The amplitude of the vibration waveform bias is centered on the photoconductor charging potential.
Within a range of ± 15% to ± 60%.
Image forming method. (5)The photosensitive drum facing the developing sleeve
An exposure means is arranged on the back side, and the developing
Through the developer rubbing area formed between the photosensitive drum and the photosensitive drum.
After charging the photoconductor while applying the image bias,
An image forming method that develops almost simultaneously with or immediately after light
In the law, A plurality containing at least a conductive magnetic carrier in the developer
Magnetic carrier and high resistance or insulating non-magnetic toner
And a carrier with the plurality of carriers.
Weight ratio of toner to toner is 4 or more
An image forming method, wherein the setting is performed. 6.The photosensitive drum facing the developing sleeve
An exposure means is arranged on the back side, and the developing
Through the developer rubbing area formed between the photosensitive drum and the photosensitive drum.
After charging the photoconductor while applying the image bias,
An image forming method that develops almost simultaneously with or immediately after light
In the law, The developer contains at least a conductive magnetic carrier.
Means multiple magnetic carriers and high resistance or insulating non-magnetic
A developer made of toner is used, and the developing via is used.
The oscillation waveform is a vibration waveform centered on the photoconductor charging potential.
If the minimum potential level is set higher than the photoconductor exposure potential
In the meantime, The peripheral speed of the developing sleeve is set to be greater than the peripheral speed of the photosensitive drum.
Image setting method set fast. 7. The magnetic carrier according to claim 1, wherein the plurality of magnetic carriers include a conductive magnetic material.
Carrier and high-resistance or insulating magnetic carrier.
7. The image forming method according to claim 1, 2, 3, 4, 5, or 6.
Method.