JPH1063061A - Device for forming image and method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device for forming image and a method therefor in which the number of parts is reduced for miniaturization and cost reduction. SOLUTION: The device has an image carrier, an electrifier for electrifying the surface of the image carrier, an exposure device 13 for forming electrostatic latent images by subjecting the surface of the image carrier to exposure, developing units 19-21 for making the electrostatic latent images into toner images of respective colors by attaching toners of the respective colors to the image part of the image carrier, a transfer drum 15 disposed in contact with the image carrier, and first and second power sources 26 and 27 for selectively applying bias voltages of different polarities to the transfer drum 15. In the case, the surface of the image carrier is electrified by the electrifier, and the surface of the electrified image carrier is subjected to the exposure by means of the exposure device 13, so that the electrostatic latent images are formed. Then, the developing units 19-21 for the respective colors attach the toners of the respective colors to the image part of the image carrier, thereby making the electrostatic latent images into the toner images of the respective colors.

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 and an image forming method.

[0002]

2. Description of the Related Art Conventionally, in an electrophotographic recording system using an intermediate transfer member, a toner image formed on an image carrier is once (temporarily) transferred (primary transfer) to an intermediate transfer member, and the intermediate transfer member is transferred to the intermediate transfer member. The toner image is further transferred to a transfer material (secondary transfer), and the electrophotographic recording method can be used for both monochrome and color (Japanese Patent Application Laid-Open No. 58-105273, 1983-105274
And JP-A-59-125765). In this case, a transfer belt, a transfer drum, or the like is used as the intermediate transfer member.

In an image forming apparatus for forming a color image by the electrophotographic recording method, a toner image of each color formed on an image carrier is sequentially superimposed on an intermediate transfer member and transferred to the color toner image. Is formed, and then the color toner images are collectively transferred to a transfer material. In the electrophotographic recording method, it is relatively easy to transfer toner images of respective colors in synchronization with an intermediate transfer member and transfer them, and it is possible to enhance the quality of color images and improve reproducibility.

Incidentally, in the electrophotographic recording system, it has been conventionally used in transferring a toner image formed on an image carrier to an intermediate transfer member and transferring a toner image of the intermediate transfer member to a transfer material. Instead of the corona transfer method, a contact transfer method is used. In the corona transfer method, not only the image is scattered or ozone is generated to deteriorate the image carrier, but also a high-voltage power supply is required to generate a high voltage, which increases the cost. .

On the other hand, in the contact transfer system, a transfer roller is pressed against an intermediate transfer member, and the intermediate transfer member is pressed against an image carrier, and a bias voltage is applied to the transfer roller and the intermediate transfer member, thereby causing electrostatic discharge. Since the toner image is transferred by force, the image is not scattered or ozone is generated, and the image carrier is not deteriorated. As a result, costs can be reduced.

[0006]

However, in the conventional image forming apparatus, an intermediate transfer member, a transfer roller, and the like are required, and the number of components is increased. Therefore, not only the size is increased, but also the cost is increased. Would. In particular, when a transfer drum is used as an intermediate transfer member, the size of the transfer drum needs to be considerably increased in order to transfer a toner image of one page to the transfer drum.

The present invention solves the above-mentioned problems of the conventional image forming apparatus, and provides an image forming apparatus and an image forming method capable of reducing the number of parts, reducing the size, and reducing the cost. The purpose is to do.

[0008]

For this purpose, in the image forming apparatus of the present invention, an image bearing member, a charging device for charging the surface of the image bearing member, and a surface of the image bearing member which are exposed to light, An exposure device for forming an electrostatic latent image, a plurality of developing devices for attaching toners of each color to an image portion of the image carrier, and converting the electrostatic latent image into a toner image of each color; and contacting the image carrier. And a first power supply for selectively applying bias voltages having different polarities to the transfer drum.

In the image forming method of the present invention, the surface of the image carrier is charged, and the surface of the image carrier is exposed to form an electrostatic latent image. To make the electrostatic latent image into a toner image of each color. And
The toner images of the respective colors are sequentially superimposed on a transfer drum and transferred to form a color toner image, the color toner images are collectively transferred to an image carrier, and the color toner images transferred to the image carrier are transferred. The images are collectively transferred to a transfer material.

In another image forming method of the present invention, the surface of the image carrier is charged, and the surface of the image carrier is exposed to form an electrostatic latent image. To form an electrostatic latent image into a toner image of each color. The color toner images are successively superimposed on the transfer drum and transferred to form a color toner image, and the color toner images are collectively transferred to a transfer material.

[0011]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a schematic diagram of an image forming apparatus according to an embodiment of the present invention. In the figure, reference numeral 11 denotes a photosensitive drum as an image carrier having a photosensitive layer made of selenium, an organic photoconductive material, etc., which is rotated in the direction of an arrow. A charging roller 13 as a charging device for uniformly and uniformly charging the surface is an exposure device that exposes the surface of the photosensitive drum 11 to form an electrostatic latent image (not shown). An array head is used. Note that a corona charger may be used as the charging device, and a laser may be used as a light source of the exposure device 13.

Reference numerals 19 to 21 denote yellow, magenta and cyan developing units, respectively. In the present embodiment, non-magnetic one-component toner developing units are used as the developing units 19 to 21, respectively. In addition, as each of the developing devices 19 to 21, a one-component magnetic brush developing device, a two-component magnetic brush developing device, or the like can be used. Further, in order to improve the quality of a color image, a black developing device can be provided in addition to the yellow, magenta and cyan developing devices.

Reference numeral 15 denotes a transfer drum as an intermediate transfer member which is disposed in contact with the photosensitive drum 11 and is rotated in the direction of the arrow. The transfer drum 15
It is formed by laminating a semiconductive elastic body on a metal support, and silicone rubber, urethane rubber or the like is used as the elastic body. In this case, the elastic body has predetermined conductivity by dispersing conductive fine particles, and the resistance is adjusted to 10 ⁶ to 10 ¹⁰ [Ω]. Further, since the toner image is transferred to the transfer drum 15, a surface of the transfer drum 15, such as a fluororesin, is Is coated. Reference numeral 22 denotes a transfer material such as printing paper.

The transfer drum 15 is a photosensitive drum 11
Is disposed in contact with the so as to form a transfer portion between the two, so that an appropriate nip width is formed in the transfer portion,
A load is applied to the transfer drum 15 toward the photosensitive drum 11. Then, the three color toner images of yellow, magenta and cyan formed on the photosensitive drum 11 are sequentially superimposed on the transfer drum 15 and transferred to form a color toner image, and the color toner image is directly or sensitized. The image is transferred to the transfer material 22 via the body drum 11.

Incidentally, in addition to the three color toner images of yellow, magenta and cyan formed on the photosensitive drum 11, a black toner image can be transferred to the transfer drum 15. A cleaning device 14 is disposed in contact with the photoconductor drum 11 and removes toner remaining on the photoconductor drum 11 after the transfer. The first power supply 26 applies a positive polarity bias voltage to the transfer drum 15, and the second power supply 27 applies a negative polarity bias voltage to the transfer drum 15. The voltage values of the first and second power supplies 26 and 27 can be appropriately changed. In the present embodiment, the cleaning device 14 is provided.
Need not necessarily be provided.

A transfer material cassette 23 for storing the transfer material 22 and a paper feed roller 24 for feeding the transfer material 22 from the transfer material cassette 23, Further, a timing roller 25 for adjusting the timing between the rotation of the photosensitive drum 11 and the conveyance of the transfer material 22 is provided. Also, transfer material 2
Downstream of the transfer section in the transport direction of the transfer material 2
Fixing device 18 for fixing the color toner image transferred to
Is arranged.

Further, the charging roller 12, the transfer drum 1
5, each of the developing devices 19 to 21 and the cleaning device 14
An operating position that can be independently moved by each of the moving mechanisms (not shown) and contacts the photosensitive drum 11,
And a retracted position separated from the photosensitive drum 11.
Next, the operation of the image forming apparatus having the above configuration will be described.

FIG. 2 is a control block diagram of the image forming apparatus according to the embodiment of the present invention. In the figure, 26 is a first power supply, 27 is a second power supply, 28 is a switch, 51 is a control unit that controls the whole of the image forming apparatus, 52 is the photosensitive drum 11 (FIG. 1), the charging roller 12, transfer A motor for rotating the drum 15 and the like; 53, a charging voltage power supply for applying the charging voltage of the charging roller 12 to the charging roller 12; 54, a charging roller 12, the transfer drum 15, the developing devices 19 to 21, and the cleaning device 14 (not shown) A moving mechanism driver that operates each moving mechanism.

In this case, the color toner images formed on the transfer drum 15 are collectively
And a first batch transfer method in which the color toner images transferred to the photosensitive drum 11 are collectively transferred from the upper surface to the transfer material 22, and the color toner image formed on the transfer drum 15 is There is a second batch transfer method in which the transfer material 22 is collectively transferred from the lower surface to the transfer material 22.

First, the first batch transfer method will be described. In this case, the surface of the photosensitive drum 11 rotated in the direction of the arrow shown in FIG. 1 is uniformly and uniformly charged to the negative polarity by the charging roller 12. In the present embodiment, a charging voltage of -1350 [V] is applied to the charging roller 12 by the charging voltage power supply 53, and the surface potential of the photosensitive drum 11 becomes -850 [V].

Next, when the exposure device 13 exposes the photosensitive drum 11 in accordance with the yellow image data, the portion of the surface of the photosensitive drum 11 which is not irradiated with light, that is, the surface potential of the non-image portion becomes -850 [V]. In contrast, the portion irradiated with light, that is, the surface potential of the image portion is −5.
0 [V], and an electrostatic latent image is formed. In this case, the yellow image data is composed of forward direction data obtained by inverting the left and right with respect to the final color image.

Subsequently, the yellow toner charged to the negative polarity by the developing device 19 is adhered to the photosensitive drum 11, and the electrostatic latent image becomes a yellow toner image by reversal development. In this case, the developing devices 20 and 21 other than the developing device 19 are placed at the retracted position by the moving mechanism. In the present embodiment, a contact-type developing device is used as the developing device 19, and the developing device 19 has a voltage of -300 [V].
Of the negative polarity is applied. When a non-contact type developing device is used as the developing device 19,
A developing bias voltage having a negative polarity of -700 [V] is applied to the developing device 19.

In the transfer section between the photosensitive drum 11 and the transfer drum 15, the transfer drum 15 is pressed against the photosensitive drum 11, and the yellow toner image is generated as the photosensitive drum 11 rotates. Is transferred to the transfer section, a bias voltage is applied to the transfer drum 15, and the yellow toner image is transferred to the transfer drum 15. Therefore, the transfer drum 15 and the first power supply 26
8 and a positive polarity of +8
A bias voltage of 00 [V] is applied.

The toner remaining on the photosensitive drum 11 after the transfer is removed by the cleaning device 14. Thereafter, the yellow toner image transferred to the transfer drum 15 is sent to the transfer unit again as the transfer drum 15 rotates. Then, similarly to the yellow toner image, the magenta toner image formed on the photosensitive drum 11 is transferred to be superimposed on the yellow toner image. When a magenta toner image is formed on the photosensitive drum 11,
The developing devices 19 and 21 other than the developing device 20 are placed at the retracted position. When a magenta toner image is transferred to the transfer drum 15, the transfer drum 15 and the first power supply 26 are connected by a switch 28, and a positive bias voltage of +800 [V] is applied to the transfer drum 15. Is done.

Similarly, the cyan toner image formed on the photosensitive drum 11 is transferred onto the yellow toner image and the magenta toner image in a superimposed manner, and a color toner image is formed on the transfer drum 15. When a cyan toner image is formed on the photosensitive drum 11, the developing devices 19 and 20 other than the developing device 21 are placed at the retracted position. When a cyan toner image is transferred to the transfer drum 15, the transfer drum 15 and the first power supply 26 are connected by a switch 28, and a positive bias voltage of +800 [V] is applied to the transfer drum 15. Is done.

When the developing bias voltages of the developing units 19 to 21 for the respective colors, the bias voltages for transferring the toner images of the respective colors to the transfer drum 15, and the like are slightly adjusted in accordance with the characteristics of the toner of the respective colors. Thus, the quality of a color image can be improved. Thereafter, the color toner image is sent to the transfer section with the rotation of the transfer drum 15, and is once transferred to the photoconductor drum 11 at once in the transfer section.

For this purpose, the developing units 19 to 21 and the transfer drum 15 are all placed in the retracted position, and the photosensitive drum 11
Is uniformly set to -50 [V] or -850 [V]. The surface potential of the photoreceptor drum 11 is uniformly -50
[V], the charging voltage applied to the charging roller 12 is set to 0 [V], and the photosensitive drum 11 is rotated one or more rotations.
1 is fully exposed. As a result, the surface potential of the photosensitive drum 11 can be uniformly set to -50 [V].

Subsequently, the cleaning device 14 and the charging roller 12 are placed at the retracted position, the transfer drum 15 is placed at the operating position, and the transfer drum 15 and the second power supply 2 are placed.
7 are connected by a switch 28, and the transfer drum 15
Is applied with a negative polarity bias voltage of -900 [V]. As a result, the photosensitive drum 11 and the transfer drum 15 can be rotated while maintaining a potential difference of 850 [V] between the photosensitive drum 11 and the transfer drum 15,
The color toner images on the transfer drum 15 are collectively transferred to the photosensitive drum 11.

On the other hand, when the surface potential of the photosensitive drum 11 is uniformly set to -850 [V], the charging voltage applied to the charging roller 12 is set to -1350 [V], and the photosensitive drum 11 is set at 1 level. Rotate more than rotation. As a result, the surface potential of the photosensitive drum 11 can be uniformly set to -850 [V]. Subsequently, the cleaning device 14 and the charging roller 12 are placed at the retracted position, the transfer drum 15 is placed at the operating position, and a bias voltage of -1700 [V] is applied to the transfer drum 15. As a result, the photosensitive drum 11 and the transfer drum 15 can be rotated while maintaining the potential difference of 850 [V] between the photosensitive drum 11 and the transfer drum 15, and the color toner image on the transfer drum 15 can be rotated. Are collectively transferred to the photosensitive drum 11.

When the color toner image is transferred to the photosensitive drum 11 in this way, the transfer material 22 is fed by the feed roller 24, and the transfer material 22 is fed by the timing roller 25. The sheet is conveyed in synchronization with the position, and is sent to the transfer section. At this time, the transfer drum 1
5 and the first power supply 26 are connected by a switch 28, and a positive polarity bias voltage of +2000 [V] is applied to the transfer drum 15.

As a result, the color toner image on the photosensitive drum 11 is transferred to the transfer material 22. Then, the transfer material 22
Is fixed by the fixing device 18 to form a color image. As described above, by changing the polarity of the bias voltage applied to the transfer drum 15, the transfer of each toner image and the transfer of the color toner image between the photosensitive drum 11 and the transfer drum 15 are performed. Since a color toner image can be transferred between the transfer material and the transfer material 22, a transfer roller is not required. Therefore, the number of components can be reduced, so that not only the size of the image forming apparatus can be reduced, but also the cost can be reduced.

When an image formed by the conventional image forming apparatus and an image formed by the image forming apparatus of the present embodiment were compared visually, no difference could be confirmed between the two. Next, the second
Will be described. In this case, the surface of the photosensitive drum 11 rotated in the direction of the arrow shown in FIG. 1 is uniformly and uniformly charged to the negative polarity by the charging roller 12. In the present embodiment, a charging voltage of −1350 [V] is applied to the charging roller 12 by the charging voltage power supply 53, and the surface potential of the photosensitive drum 11 becomes −.
850 [V].

Next, when the exposure device 13 exposes the photosensitive drum 11 in accordance with the yellow image data, the portion of the surface of the photosensitive drum 11 which is not irradiated with light, that is, the non-image portion has a surface potential of -850 [V]. In contrast, the portion irradiated with light, that is, the surface potential of the image portion is −5.
0 [V], and an electrostatic latent image is formed. In this case, the yellow image data includes left-right inverted data in which the left and right are the same as the final color image.

Subsequently, yellow toner charged to a negative polarity by the developing device 19 is adhered to the photosensitive drum 11, and the electrostatic latent image is converted into a yellow toner image by reversal development. In this case, the developing devices 20 and 21 other than the developing device 19 are placed at the retracted position by the moving mechanism. In the present embodiment, a contact-type developing device is used as the developing device 19, and the developing device 19 has a voltage of -300 [V].
Of the negative polarity is applied. When a non-contact type developing device is used as the developing device 19,
A developing bias voltage having a negative polarity of -700 [V] is applied to the developing device 19.

In the transfer portion between the photosensitive drum 11 and the transfer drum 15, the transfer drum 15 is pressed against the photosensitive drum 11, and the yellow toner image is produced as the photosensitive drum 11 rotates. Is transferred to the transfer section, a bias voltage is applied to the transfer drum 15, and the yellow toner image is transferred to the transfer drum 15. Therefore, the transfer drum 15 and the first power supply 26
8 and a positive polarity of +8
A bias voltage of 00 [V] is applied.

The toner remaining on the photosensitive drum 11 after the transfer is removed by the cleaning device 14. Thereafter, the yellow toner image transferred to the transfer drum 15 is sent to the transfer unit again as the transfer drum 15 rotates. Then, similarly to the yellow toner image, the magenta toner image formed on the photosensitive drum 11 is transferred to be superimposed on the yellow toner image. When a magenta toner image is formed on the photosensitive drum 11,
The developing devices 19 and 21 other than the developing device 20 are placed at the retracted position. When transferring the magenta toner image to the transfer drum 15, the transfer drum 15 and the first power supply 26 are connected by a switch 28, and a positive bias voltage of +800 [V] is applied to the transfer drum 15. Is done.

Similarly, the cyan toner image formed on the photosensitive drum 11 is transferred onto the yellow toner image and the magenta toner image in a superimposed manner, and a color toner image is formed on the transfer drum 15. When a cyan toner image is formed on the photosensitive drum 11, the developing devices 19 and 20 other than the developing device 21 are placed at the retracted position. When a cyan toner image is transferred to the transfer drum 15, the transfer drum 15 and the first power supply 26 are connected by a switch 28, and a positive bias voltage of +800 [V] is applied to the transfer drum 15. Is done.

When the developing bias voltages of the developing units 19 to 21 of the respective colors, the bias voltages for transferring the toner images of the respective colors to the transfer drum 15, and the like are slightly adjusted in accordance with the characteristics of the toner of the respective colors. Thus, the quality of a color image can be improved. Thereafter, the color toner image is sent to the transfer section as the transfer drum 15 rotates.

On the other hand, when a color toner image is formed on the transfer drum 15, the transfer material 2 is
2 is fed, and the transfer material 22 is
Is conveyed in synchronism with the position of the color toner image and sent to the transfer section. At this time, the transfer drum 15 and the second power supply 27 are connected by the switch 28, and a negative bias voltage of -2000 [V] is applied to the transfer drum 15.

As a result, the color toner images on the transfer drum 15 are collectively transferred to the transfer material 22. Then, the color toner image transferred to the transfer material 22 is fixed by the fixing device 18 to form a color image. As described above, by changing the polarity of the bias voltage applied to the transfer drum 15, the photosensitive drum 11 and the transfer drum 1 are changed.
5 and transfer of a color toner image between the transfer drum 15 and the transfer material 22, respectively, so that a transfer roller is not required. Therefore, the number of components can be reduced, so that not only the size of the image forming apparatus can be reduced, but also the cost can be reduced.

Incidentally, when an image formed by the conventional image forming apparatus and an image formed by the image forming apparatus of the present embodiment were visually compared, no difference could be confirmed between the two. In addition, since it is not necessary to transfer the color toner image to the photosensitive drum 11 once, all of the developing units 19 to 21 and the transfer drum 15 may be placed at the retracted position, or the surface potential of the photosensitive drum 11 may be uniformly reduced. There is no need to set it to 50 [V] or -850 [V]. Therefore, the image forming speed can be increased.

The present invention is not limited to the above embodiment, but can be variously modified based on the spirit of the present invention, and these are not excluded from the scope of the present invention.

[0043]

As described above in detail, according to the present invention, in an image forming apparatus, an image carrier, a charging device for charging the surface of the image carrier, and a surface of the image carrier are provided. An exposure device for exposing to form an electrostatic latent image; a plurality of developing devices for attaching toners of each color to an image portion of the image carrier to convert the electrostatic latent image into a toner image of each color; A transfer drum disposed in contact with the first and second transfer drums;
A second power supply.

In this case, the surface of the image carrier is charged by the charging device, and the charged surface of the image carrier is exposed by the exposure device to form an electrostatic latent image. Then, the developing units for the respective colors adhere the toners of the respective colors to the image portions of the image carrier, and convert the electrostatic latent images into the toner images of the respective colors. Next, when a bias voltage is applied to the transfer drum by the first power supply, the toner images of the respective colors on the image carrier are sequentially transferred onto the transfer drum in a superimposed manner, and a color toner image is formed.

Then, a bias voltage is applied to the transfer drum by the second power supply, and the color toner images on the transfer drum are collectively transferred to the image carrier. Then, the bias voltage is applied to the transfer drum by the first power supply. When the voltage is applied, the color toner images transferred to the image carrier can be collectively transferred to the transfer material. Alternatively, a bias voltage may be applied to the transfer drum by the second power supply, and the color toner image on the transfer drum may be collectively transferred to the transfer material.

Therefore, since the transfer roller is not required, the number of components can be reduced, and the size of the image forming apparatus can be reduced, and the cost can be reduced. In the image forming method of the present invention, the surface of the image carrier is charged, the surface of the image carrier is exposed to form an electrostatic latent image, and the toner of each color is attached to the image portion of the image carrier. Then, the electrostatic latent image is converted into a toner image of each color.

The color toner images are sequentially superimposed on the transfer drum and transferred to form a color toner image, and the color toner images are collectively transferred to the image carrier and transferred to the image carrier. The transferred color toner images are collectively transferred to a transfer material. In this case, since the color toner image is transferred to the transfer material via the image carrier, a transfer roller is not required. Therefore, the number of parts can be reduced, and the size of the image forming apparatus can be reduced, and the cost can be reduced.

In another image forming method of the present invention, the surface of the image carrier is charged, and the surface of the image carrier is exposed to form an electrostatic latent image. To form an electrostatic latent image into a toner image of each color. The color toner images are successively superimposed on the transfer drum and transferred to form a color toner image, and the color toner images are collectively transferred to a transfer material.

In this case, since the transfer material passes between the transfer drum and the image carrier, a transfer roller is not required. Therefore, the number of parts can be reduced, and the size of the image forming apparatus can be reduced, and the cost can be reduced. Further, it is not necessary to temporarily transfer the color toner image formed on the transfer drum to the image carrier. Therefore, the color toner image formed on the transfer drum can be directly transferred to the transfer material, so that the image forming speed can be increased accordingly.

[Brief description of the drawings]

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

FIG. 2 is a control block diagram of the image forming apparatus according to the embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Photoconductor drum 12 Charging roller 13 Exposure apparatus 15 Transfer drum 19-21 Developing device 22 Transfer material 26 1st power supply 27 2nd power supply

Claims (4)

[Claims] 1. An image carrier, (b) a charging device for charging the surface of the image carrier, and (c) an exposure for exposing the surface of the image carrier to form an electrostatic latent image. A plurality of developing devices for adhering toner of each color to an image portion of the image carrier to convert an electrostatic latent image into a toner image of each color; and (e) contacting with the image carrier. (F) a transfer drum provided
An image forming apparatus comprising: a first power supply and a second power supply that selectively apply bias voltages having different polarities to the transfer drum. (A) applying a bias voltage from the first power supply to the transfer drum to transfer the toner image on the image carrier to one of a transfer drum and a transfer material; 2. A toner image on the transfer drum is transferred to one of an image carrier and a transfer material by applying a bias voltage to the transfer drum from a power supply of the second aspect.
An image forming apparatus according to claim 1. (A) charging the surface of the image carrier;
(B) exposing the surface of the image carrier to form an electrostatic latent image;
(C) adhering toner of each color to the image portion of the image carrier to form an electrostatic latent image into a toner image of each color;
The toner images of the respective colors are sequentially superimposed on a transfer drum and transferred to form a color toner image. (E) The color toner images are collectively transferred to an image carrier, and (f) the color toner images are transferred to the image carrier. An image forming method, wherein the transferred color toner images are collectively transferred to a transfer material. And (a) charging the surface of the image bearing member,
(B) exposing the surface of the image carrier to form an electrostatic latent image;
(C) adhering toner of each color to the image portion of the image carrier to form an electrostatic latent image into a toner image of each color;
An image forming method, wherein a color toner image is formed by successively transferring the toner images of the respective colors onto a transfer drum to form a color toner image, and (e) transferring the color toner images collectively to a transfer material.