JPH036500B2 - - Google Patents

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to an image forming method and apparatus for forming a multi-image toner image in which a plurality of image toner images are superimposed on an image support, and relates to an image forming method and apparatus for forming a multi-image toner image on an image support. electronic records,
Used for facsimiles, transmission records, laser printers, etc.

[Prior art]

In general, in an image forming method and apparatus that forms a plurality of toner images, for example, a color image forming method and apparatus, the recorded image that is formed has high color density in the image area, less fog in the non-image area, and is faithful to the original. It is required to have good gradation and good color balance. Therefore, for example, JP-A No. 49-74034, JP-A No. 49-127629, JP-A No. 50-Sho.
No. 20730 describes a technique in which a reference patch is used to form a reference toner image on an image support, and the image quality of a color image is controlled by information from the reference toner image. In such known technology,
For example, a color image is formed by the following method. That is, a reference patch is placed on the document table at a position where it receives light from a light source before the original and the original, and the reference patch and the reference patch from the original are placed on a photoreceptor that has been uniformly charged in advance. The reflected light is subjected to image exposure through, for example, a blue filter to form a reference latent image and an image latent image. Next, the reference latent image is first developed by a developing device containing yellow toner to form a yellow reference toner image, and subsequently a yellow image toner image controlled by information from the reference toner image is formed. This image toner image is transferred onto recording paper fed at the same timing from a paper feeding device. On the other hand, the photoreceptor is cleaned of the reference toner image and the residual toner image, and after the residual charge is erased, it is uniformly charged again and imagewise exposed through a green filter to form a reference latent image and an image latent image. is formed. Next, the reference latent image is developed by the developing device containing magenta toner to form a magenta reference toner image in the same manner as before, and subsequently a magenta image toner image is formed under control based on information from the reference toner image. The magenta reference toner image is cleaned and removed, but this magenta toner image is superimposed and transferred onto the recording paper onto which the yellow toner image has already been transferred in the previous step. Similarly, the cyan image toner image is further transferred, and a multi-image toner image in which the three primary color toner images are superimposed is obtained on the recording paper. Next, this recording paper is separated from the transfer drum, and after being fixed, it is discharged outside the machine.

This image forming method has the advantage of being able to provide a color image with improved image characteristics on the one hand, but on the other hand, (a) it requires a transfer drum to transfer the image to the recording paper each time the development of each color is completed. (b) The development process and transfer process are repeated many times, resulting in misalignment of the toner images of each color, which is unsightly. There are problems such as color images being formed.

Therefore, for example, in Japanese Patent Application Laid-Open No. 56-144452, Japanese Patent Application No. 58-183152, and Japanese Patent Application No. 58-184381, a plurality of color toner images are superimposed on an image support by a reversal development method or the like. A technique has been proposed in which the images are formed simultaneously and transferred onto recording paper at the same time. The typical image forming principle of the technique described below will be explained based on the flowchart of FIG.

In FIG. 5, S is, for example, a drum-shaped photoreceptor, E is a positive surface potential applied to the surface of the photoreceptor S, PH is an image exposed area of the photoreceptor S, and DA is an unexposed area of the photoreceptor S. , DUP is the increase in potential caused by the positively charged toner T adhering to the exposed area PH during the first development, and CUP is the increased potential caused by the second charging.
Indicates the increase in PH potential.

The photoreceptor S is uniformly charged by a scorotron charger or the like to give a constant positive surface potential E. This surface potential E decreases to a point where the potential of the exposed portion PH is close to zero by the first imagewise exposure. Here, by performing so-called reversal development in which development is performed by applying a positive bias whose DC component is approximately close to the surface potential E of the unexposed area to the developing device,
The positively charged toner T in the developing device comes to adhere to the exposed portion PH, which has a relatively low potential, and a first toner image (for example, a yellow toner image) is formed.
In the area where the toner image is formed, the potential increases by DUP due to the adhesion of positively charged toner, but
Next, a second charge is applied by the scorotron charger, and the potential is further increased by the amount of CPU to obtain a potential close to the surface potential E of the non-exposed area. Next, a second imagewise exposure is performed on the surface of the photoreceptor S, on which a substantially uniform surface potential E has been obtained, to form an electrostatic charge image, and after a similar development operation, a second image on which magenta toner T' is attached is applied. 2 toner images (for example, magenta toner images) are obtained. By repeating the above process, a multicolor toner image in which a third toner image (for example, a cyan toner image) etc. is superimposed on the photoreceptor S is obtained. This multicolor toner image is transferred onto recording paper, fixed by pressure or heat, and then discharged. On the other hand, the photoreceptor S after the transfer is cleaned by a cleaning device and prepared for the next image formation.

According to the above-described image forming principle, the transfer process is performed only once, and there are advantages such as eliminating problems such as an increase in the size of the apparatus, a long image formation time, and misalignment of the toner images of each color.

However, in the case of an image toner image formed by superimposing toner images of each color on an image support, the information on the reference toner image for each color as described in the above-mentioned Japanese Patent Laid-Open No. 49-74034 etc. does not provide a desirable image. There is a problem that control of characteristics cannot be achieved. That is,
Even if the image toner images of each color are controlled, there is a problem in that a high quality color image cannot be obtained as a result because the superimposed multiple image toner images are not controlled. Also, the above-mentioned Japanese Patent Application Laid-open No. 1973-
In the case of an image forming apparatus such as that described in Publication No. 74034, a reference toner image is formed at a previous position on the image support, and a reference toner image is formed at a later position based on information from the reference toner image. The area required for the image support increases. For this reason, there are problems in that the entire image forming apparatus becomes large and cannot be made compact.

[Problems to be solved by the present invention]

The problem to be solved by the present invention is that in an image forming apparatus that forms a multi-image toner image by superimposing a plurality of image toner images on an image support, a reference toner image is separately formed and the image toner image is The object of the present invention is to improve the image quality of multicolor images by controlling and forming them using information from a reference toner image. or,
An object of the present invention is to form an image toner image after a reference toner image is removed, thereby downsizing the image support and making the entire image device more compact.

[Means to solve the problem]

The above-mentioned problem arises in an image forming method in which toner images of multiple colors are superimposed on an image support, and reference toner images of multiple colors are formed on the image support to control the conditions for forming the toner image. to obtain information from the reference toner image, remove the reference toner image from the image support without transferring it, and then charge, expose, and develop the multi-color image toner image based on the information. An image forming method characterized in that the image support is repeatedly formed for each rotation of the image support, and then transferred, and the image support, a charger, a single exposure device, a plurality of developing devices, and the image support. and a cleaning device for cleaning the image support, the image forming apparatus forms an image toner image every rotation of the image support, and superimposes the image toner images of a plurality of colors on the image support. After forming a plurality of color reference toner images on the image support to control the formation conditions of the image toner image and obtaining information from the reference toner image, the reference toner image is transferred without transferring the reference toner image. This is achieved by an image forming apparatus characterized in that the toner images are removed from the image support by a cleaning device, and then the toner images of the plurality of colors are formed based on the information and then transferred.

[Effect]

In the image forming apparatus having the above configuration, the information of the reference toner image previously formed on the image support is stored in the memory, the toner image is removed by the cleaning device, and then the information stored in the memory is An image toner image is formed under the control of: The image support may be in the form of a drum or an endless belt, and image formation may be performed in one rotation or in multiple rotations corresponding to the number of toner images. In the one-rotation system, when a toner image is formed after the reference toner is removed and the image support is, for example, a photoreceptor on a drum, the drum diameter can be made extremely small in principle. However, since the number of image forming devices around the drum is large, it is difficult to reduce the diameter of the drum, and it is complicated, so a multiple rotation system is usually preferably adopted.

In the multiple rotation method, the drum diameter can be reduced to approximately the image length. For example, in the case of a B4 size image, the drum diameter can be reduced to a circumference of approximately 370 mm.

The reference toner image and the image toner image in the present invention are subjected to imagewise exposure on an image support member uniformly charged in advance to form a reference latent image and an image latent image,
Next, the toner is sequentially developed by a plurality of developing devices containing toner of each color. For the image exposure, the image signal may be, for example, an output signal of an image sensor that scans a document, a transmission signal from another device, or data stored in a storage device, such as a laser light source, OFT, liquid crystal shutter, LED, etc. This is done by modulating or driving the signal.

As the plurality of developing devices, a developing device that performs reversal development based on the image forming principle in the flowchart of FIG. 5 and performs non-contact development at least from the second time onward is preferably used. The non-contact developing method applies an alternating current bias to the developing device,
The stored toner is caused to fly toward the image support for development, and the on/off of the developing operation is controlled only by turning on/off the AC bias. Therefore,
The development steps of the reference latent image and the image latent image are performed without being influenced by each other. Also, the AC bias
When set to off, it is preferable that only a DC bias in a direction that prevents toner from flying is applied. Further, in order to turn off the developing operation, the developing device is separated from the image support, the entire developing device is grounded using a means for removing the developer layer from the sleeve surface, or it is floated. It may be.

The image forming mode of the reference toner image and the image toner image in the present invention can take various modes, and representative examples thereof are shown in the flowchart of FIGS. 1 to 3 and the image forming apparatus of FIG. 4. This will be explained using a partial cross-sectional view. Reference numeral 1 in FIGS. 1 to 3 shows a planar development of the drum-shaped photoreceptor shown in FIG. 5, and arrows indicate the direction of movement of the surface of the photoreceptor.

The photoreceptor 1 shown in FIGS. 1 to 3 is first uniformly charged positively and then imagewise exposed by an exposure system modulated or driven based on a reference signal to form a reference latent image. Next, the yellow developing device 5, magenta developing device 6, and cyan developing device 7 shown in FIG. 5 perform non-contact reversal development to form a multiple reference toner image 2c in which the three color reference toner images are superimposed. Here, information on the reference toner image is stored in a memory and removed by a cleaning device, and then image exposure modulated or driven by an image signal is performed while being controlled by the memory information to form a latent image. It is formed. Then, similarly controlled by the memory information, the developing device 5,
6 and 7 to form a multi-image toner image 3c in which the three-color image toner images are superimposed.

Hereinafter, specific image forming modes in each flowchart and their differences will be explained. In FIG. 1, an image support 1 is uniformly positively charged and then imagewise exposed based on a yellow reference signal to form a reference latent image. Thereafter, it is developed by the developing device 5 to form a yellow toner image 2a.
Next, magenta toner development is performed by the developing device 6 without performing charging and image exposure, and a reference toner image 2b is formed in which a magenta toner image is superimposed on the yellow toner image 2a at the same position. Furthermore, cyan toner development is carried out by the developing device 7 in the same manner, and a multiple reference toner image 2c in which three color toner images are superimposed at the same position is formed by either one rotation or three rotations of the image support 1.

This reference toner image 2c is removed by a cleaning device, and then an image latent image and an image toner image are formed using substantially the entire surface of the image support 1 based on information from the reference toner images 2a to 2c. That is, the image support 1 from which the reference toner image 2c has been removed is uniformly positively charged, imagewise exposed based on the yellow image signal to form an image latent image, and then the developing device 5 is developed to form a yellow toner image 3a. Next, uniform charging and image exposure based on the magenta image signal are performed again to form a latent image, and then magenta toner development is performed by the developing device 6, and a magenta toner image is formed on the yellow toner image 3a. A superimposed image toner image 3b is formed. Furthermore, cyan toner development is similarly performed by the developing device 7, and a multiple image 3c in which three color toner images are superimposed is formed by three rotations of the image support 1. This toner image 3c is transferred and fixed onto the recording paper by a transfer device. The image support 1 after the transfer is cleaned and prepared for the next image formation.

The flowchart in Figure 2 differs from the flowchart in Figure 1 in that the reference toner images of each color are uniformly charged, exposed, and developed, and are formed at different positions. There is. That is, after a uniform positive charge is applied to the image support 1, image exposure is performed based on a yellow reference signal to form an electrostatic charge image, and then yellow toner development is performed to form a yellow reference toner image 2a. is formed. Next, after being recharged, image exposure is performed based on the magenta reference signal to form the yellow toner image 2a.
An image latent image is formed at a position different from the image, and this latent image is further developed with magenta toner to form a magenta toner image. This magenta toner image and the yellow toner image 2a are superimposed at different positions to form a reference toner image 2b. Similarly, cyan toner images are also superimposed at different positions to form a multiple reference toner image 2c by three rotations of the image support 1.

In the flowchart of FIG. 3, writing is performed in three colors on the image support 1 at once based on the reference signal, and reference latent images 4 for each color are formed at different positions, as shown in FIG. , which is different from the flowchart in FIG. Also, in the flowchart of FIG. 2, the multiple reference toner images are formed by three rotations of the image support, but in this case, the multiple reference toner images are formed by one rotation. That is, after uniformly positively charging the image support 1, three color reference signals of yellow, magenta and cyan are simultaneously written to form reference latent images 4 at different positions.
This reference latent image is sequentially developed by the developing devices 5, 6, and 7, and a superimposed multiple reference toner image 2c is formed by one rotation of the image support.

Overlapping the toner images in the above solid image forming method means that the toner images of each color are formed in a common area, and when the toner adhesion parts all overlap at the same position, when they partially overlap, or when they all overlap. It may be either case.

EXAMPLES The present invention will be specifically explained below with reference to Examples, but the embodiments of the present invention are not limited thereto.

Embodiment 1 FIGS. 6 to 10 are diagrams explaining this embodiment, in which FIG. 6 is a sectional view of main parts of a three-color image forming apparatus, FIG. 7 is a sectional view of an exposure apparatus using laser light, FIG. 8 is a sectional view of the developing device, FIG. 9 is a flowchart explaining the development mode of the reference toner image,
FIG. 10 is a flowchart illustrating the development mode of a toner image.

In this embodiment, image formation is performed by the image forming apparatus shown in FIG. 6 based on the flowchart shown in FIG. Reference numeral 10 denotes an image support made of a drum-shaped selenium photoreceptor with a diameter of 120 mm, which is rotated in the direction of the arrow at a circumferential speed of 180 mm/sec. Reference numeral 11 denotes a scorotron charger, and the surface of the photoreceptor 10 is uniformly charged to +600V by the charger 11. Next, the yellow reference signal is input to the laser device 12 having the structure shown in FIG. 7, and the laser beam _L1 modulated by the signal is irradiated onto the charged surface of the image support 10 (first image exposure). A reference latent image is formed. Thereafter, as shown in the development mode of FIG. 9, reversal development (first development) is performed by the development device 13 to form a reference toner image (FIG. 1, 2a) to which the yellow toner T is attached. Next, the developing device 14 performs reversal development (second development) without performing charging or image exposure.
The magenta toner T' adheres to the yellow toner T to form a reference toner image (FIG. 1, 2b). A multiple reference toner image (see FIG. 1, 2
c) is formed by one revolution of the image support 10.

This multiple reference toner image, whose information is stored in the memory, is removed by the action of the pre-cleaning static eliminator 20 and the blade 22 of the cleaning device 21, and is then removed using almost the entire surface of the image support 10 based on the memory information. An image toner image is formed. That is, after a uniform charge of +600V is applied to the surface of the image support 10, a latent image is formed by irradiation with laser light _L2 from the laser device 12 modulated by a yellow image signal (first image exposure). formed,
The toner image is developed by the developing device 13 (first development) to form a yellow toner image (FIG. 1, 3a). Next, an image latent image is formed on the image support 10 by irradiation with the laser beam L ₂ modulated by the magenta image signal (second image exposure) after being recharged, and further developed by the developing device 15 (second image exposure). A magenta image toner image is formed superimposed on the yellow image toner image (FIG. 1, 3b).
Similarly, recharging, image exposure based on the cyan image signal (third image exposure), and development by the developing device 15 (third development) are performed to form a multi-image toner image (FIG. 1, 3c) on the image support. It is formed by three rotations of 10. The flowchart of FIG. 10 shows the image toner image development mode. That is, the toner that is attached during the second or third development is attached to both the area where toner was attached in the previous step and the area where toner was not attached.

After this image toner image is given transferability by the action of the pre-transfer charger 16 and the pre-transfer exposure device 17, it is transferred to a transfer electrode onto a recording paper P of, for example, B4 size, which is supplied in synchronization with the image support 10. It is transferred by the action of 18. Thereafter, this recording paper P is transported by transport rollers 19, fixed and discharged. On the other hand, after the image support 10 has been transferred, the charge is removed by the charge removal device 13, and the residual toner is cleaned by the blade 22 of the cleaning device 21, which was released during image formation.

FIG. 7 is a cross-sectional view showing the configuration of the laser device 12, in which 23 is a laser light source, 24 is a modulator that performs modulation operation based on an external signal, 25 is a polygonal reflector, and 26
is an imaging fθ-lens, and 27 and 28 are reflecting mirrors.

FIG. 8 is a cross-sectional view illustrating the structure of the developing devices 13, 14, and 15, in which 29 is a developing sleeve made of a non-magnetic material such as aluminum or stainless steel, and 30 is provided inside the developing sleeve 29. A magnet body having a plurality of magnetic poles in the circumferential direction; 31 is a layer thickness regulation blade made of a magnetic or non-magnetic material that regulates the thickness of the developer layer formed on the developing sleeve 31; 32 is a layer thickness regulation blade for regulating the thickness of the developer layer formed on the developing sleeve 29; A scraper blade 34 stirs the developer in the developer reservoir 33; 36 a toner hopper; 35 has a recess on the surface into which toner enters; The toner replenishing roller 37 applies a bias voltage including an oscillating voltage component in some cases to the developing sleeve 29 via a protective resistor 38,
This is a power source for forming an electric field to control the movement of toner between the developing sleeve 29 and the image support 10, and the figure shows that the developing sleeve 29 and the magnet 30 rotate in the directions of the arrows. However, even if the developing sleeve 29 is fixed,
The magnet body 30 may be fixed, or the developing sleeve 29 and the magnet body 30 may rotate in the same direction. When the magnet body 30 is fixed, normally, in order to make the magnetic flux density of the magnetic pole facing the image support body 10 larger than the magnetic flux density of other magnetic poles, the magnetization is strengthened or a magnetic pole of the same or different polarity is attached thereto. The two magnetic poles may be placed close to each other.

In such a developing device, the magnetic pole of the magnet body 30 is usually
It is magnetized to a magnetic flux density of 500 to 1500 Gauss,
The developer in the developer reservoir 33 is attracted to the surface of the developing sleeve 29 by the magnetic force, and the thickness of the adsorbed developer is regulated by the layer thickness regulating blade 31 to form a developer layer. The developer layer is the image support 1
The latent image on the image support 10 is developed in the development area E where the surface of the development sleeve 29 faces the surface of the image support 10 by moving in the same direction or in the opposite direction (in the figure, the same direction) as the direction of the rotation arrow 0. However, the remainder is removed from the surface of the developing sleeve 29 by the scraper blade 32 and returned to the developer reservoir 33. The development is repeated in order to superimpose the color toner images, and at least for the second and subsequent development, the toner attached to the image support 10 in the previous development is not shifted in the subsequent development. As such, it is preferable to use non-contact development conditions.

In this embodiment, the reference latent image is developed using the vibration bias in the power supply 37 of the developing devices 13, 14, 15, etc. as a reference vibration bias, and a reference toner image is created. This reference toner image is detected by, for example, an optical means that measures reflection density using a combination of a light emitting element and a light receiving element. This detected information is compared with a memory stored in the CPU in advance, and an appropriate bias value is selected as the voltage to be applied when developing the image latent image. or,
An appropriate value is selected from among reference vibration bias values that vary according to a certain program and is used as a bias value when developing a latent image. Furthermore, CPU
image support 1 compared to the memory stored in the image support 1
The charging potential to zero and/or the image exposure amount are controlled. In addition, 39 in FIG. 8 is a D/A converter, and 40
is an A/D converter, and 41 is a photo sensor for measuring reflection density.

Next, in this embodiment, the power supply 37 is normally
AC bias of 1.2KV at 2KHz when on, +
This value is controlled to vary by information from a reference toner image to which a 500V DC bias is applied.
Also, the sleeve 41 has a diameter of 30 mm and a rotation speed of 65 r.pm in the direction of the arrow.
The gap d between the developing area E and the image support 10 was set to 1000 μm. The gap between the sleeve 29 and the thick film regulating blade 31 is 300 μm, the formed developer layer is about 700 μm, and the magnetic flux density is N with a magnetic flux density of 900 Gauss.
The rotation speed in the direction of the arrow of the magnet body 30 having six S magnetic poles at equal intervals was 700 rpm.

As for the developer used in this embodiment, it is not necessary to include a black or brown magnetic material in the toner, and a toner with a clear color can be obtained, and the charging of the toner can be easily controlled. It is preferred to use a so-called two-component developer consisting of a mixture of a non-magnetic toner and a magnetic carrier. In particular, the magnetic carrier may be made of styrene resin, vinyl resin, ethyl resin, rosin modified resin, acrylic resin, polyamide resin,
Fine particles of ferromagnetic or paramagnetic substances such as triiron tetroxide, γ-ferric oxide, chromium dioxide, manganese oxide, ferrite, manganese-copper alloy, etc. are dispersed in resins such as epoxy resin and polyester resin. The resistivity is made by coating the surface of these magnetic particles with the above-mentioned resin.
Preferably it is an insulating carrier of at least 10 ⁸ Ωcm, preferably at least 10 ¹³ Ωcm. If this resistivity is low, when a bias voltage is applied to the developing sleeve 31, charges may be injected into the carrier particles, making it easy for the carrier particles to adhere to the surface of the image support. The problem arises that no voltage is applied. In particular, if the carrier adheres to the image support 10, the tone of the color image will be adversely affected.

The resistivity was determined by placing the particles in a container with a cross-sectional area of 0.50 cm ² and tapping them, then applying a load of 1 kg/cm ² on the packed particles, and applying a load of 1 kg/cm 2 between the electrode that also served as the load and the bottom electrode. This value is obtained by reading the current value when a voltage is applied that generates an electric field of 1000 V/cm.

Furthermore, if the average particle size of the carrier is less than 5 μm, the magnetization will be too weak, and if it exceeds 50 μm, the image will not be improved, breakdown or discharge will easily occur, and high voltage will not be able to be applied. It is preferable that the diameter is 5 μm or more and 50 μm or less,
If necessary, a fluidizing agent such as hydrophobic silica may be appropriately added as an additive.

The toner preferably has an average particle size of 1 to 20 μm, and has an average charge amount of 3 to 300 μc/cm.
g, particularly preferably 5 to 30 μc/g. When the average particle size of toner is less than 1 μm, it becomes difficult to separate from the carrier, and when it exceeds 20 μm, image resolution begins to decrease.

When a developer made of a mixture of an insulating carrier and toner as described above is used, the bias voltage applied to the developing sleeve 31 shown in FIG. This makes it easy to configure settings without fear of leaks. In order to more effectively control the development movement of the toner by applying such a bias voltage, the toner may contain a magnetic material to the extent that the clarity of the color is not impaired so that it can be used in a magnetic carrier. Good too.

Of course, in the present invention, not only the two-component developer but also the one-component developer described in U.S. Pat. A non-contact development method can also be used. Also, JP-A-56-125753, JP-A-59
-42565, patent application No. 1983-97973, patent application No. 1983
-231434 can also be used.

In this example, magnetite is added to the resin.
Average particle size 20μm with 50% dispersion content, magnetization
A carrier having a resistivity of 30 emu/g and a resistivity of 10 ¹⁴ Ωcm or more is used. In addition, as a toner, a benzidine derivative is used as a yellow pigment in a styrene-acrylic resin.
Rhodamine B is used as a magenta pigment, 10 parts by weight of a copper phthalocyanine pigment is used as a cyan pigment, and 2 parts by weight of a positive charge control agent are used, with an average particle size of 10 μm. In this embodiment, a developer is used in which the content ratio of toner to the developer is adjusted to be 20% by weight.

In this embodiment, a method is adopted in which a reference toner image and an image toner image are formed using a reference signal and an image signal from the outside, and the image toner image is formed after the reference toner image is removed. Since this method is adopted, the formation position and formation method of the reference toner image can be selected from a wide range. The reference toner image may also be activated from an image signal or may be imaged by a signal from a light wedge provided with a constant color density difference. Further, the order in which the cyan, magenta, and yellow color toner images are formed may be arbitrarily changed depending on the situation.

Embodiment 2 The difference between this embodiment and Embodiment 1 is that the yellow, magenta, and cyan color reference toner images are not superimposed at the same position, but are placed at separate locations close to each other as shown in the flowchart of FIG. The position is formed by rotating the image support 10 three times. For this reason, charging, exposure, and development must be repeated each time each reference toner image is formed, and this process is performed in the first step.
This is shown in the flowchart in Figure 1. That is, the toner adhesion position in the first development is different from the toner adhesion position in the second development. On the other hand,
The image forming mode of the reference toner image in this embodiment is close to the image forming mode of the image toner image, and has the advantage that effective information can be easily obtained.

〔Effect of the invention〕

As is clear from the above examples, in the present invention, a plurality of toner images are superimposed on an image support and transferred onto recording paper at once, so a transfer drum is not required. In addition, since the image toner image can be formed using almost the entire surface of the image support, the image support can be downsized, and the image forming apparatus can be made even more compact. Furthermore, since image formation is performed based on information from the reference toner image, a multicolor image with good image quality, gradation, and color balance can be obtained. Furthermore, when multiple toner images are superimposed on the image support, a reversal development method and a non-contact development method are used, which not only provides clear images and reduces fatigue of the photoreceptor, but also allows Many effects can be achieved, such as the ability to easily and efficiently control the developing operation when developing an image.

[Brief explanation of the drawing]

1, 2, and 3 are flowcharts for explaining a preferred image forming mode of the present invention, FIG. 4 is a partial sectional view of an image forming apparatus for explaining the flowchart, and FIG. 5 shows a flowchart explaining an image forming mode using a known reversal development method.
FIG. 6 is a sectional view of a main part of an image forming apparatus explaining an embodiment, FIG. 7 is a sectional view of a laser device, FIG. 8 is a sectional view of a developing device, and FIG. 9 is a sectional view of a reference toner image of Example 1. Flowchart explaining development mode, 1st
FIG. 0 is a flowchart illustrating the development mode of the image toner image of the embodiment, and FIG. 11 shows the development mode of the reference toner image of the second embodiment. 10...Drum-shaped photoreceptor, 11...Scorotron charger, 12...Laser device, 13, 14, 1
5...Developer, 16...Pre-transfer exposure device, 17...
Pre-transfer charger, 18...Transfer electrode, 29...Sleeve, 30...Magnet, 31...Layer thickness regulation blade, E...Development area, 37...Development bias, 3
9...D/A converter, 40...A/D converter, 4
1...Photo sensor, T, T'...Toner, D
...Developer, P...Recording paper, Y, M, C...Yellow, magenta, cyan.

Claims (1)

[Scope of Claims] 1. In an image forming method in which toner images of a plurality of colors are superimposed on an image support, a reference toner image of a plurality of colors is placed on the image support for controlling the formation conditions of the toner image. After forming and obtaining information from the reference toner image, removing the reference toner image from the image support without transfer, and subsequently charging and exposing the multi-color image toner image based on the information. An image forming method comprising repeating steps of and development for each rotation of the image support, and then transferring the image. 2. An image supporting member, a charger, a single exposure device, a plurality of developing devices, and a cleaning device for cleaning the image supporting member, and forming a toner image every rotation of the image supporting member. , an image forming apparatus for superimposing toner images of a plurality of colors on the image support, wherein a reference toner image of a plurality of colors is formed on the image support for controlling the formation conditions of the toner image. to obtain information from the reference toner image, remove the reference toner image from the image support by the cleaning device without transferring it, and then form the plurality of color image toner images based on the information. An image forming apparatus characterized in that the image forming apparatus performs transfer after transferring.