JP3506344B2 - Image forming device - 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 such as a copying machine, a facsimile or a printer, and more specifically, a developing device for developing a latent image on an image bearing member, and a developing device for developing the latent image. A transfer device that transfers the visible image on the image carrier to a transfer material, and a cleaning device that presses a cleaning blade against the surface of the image carrier to remove the toner remaining on the image carrier to which the visible image has been transferred. And an image forming apparatus including the apparatus.

[0002]

2. Description of the Related Art In recent years, the image quality of image forming apparatuses of this type has been improved, and as one direction for improving the image quality, the toner used in the apparatus has been reduced in diameter. However, if the diameter of the toner is simply reduced by a pulverizing method, which is one of the toner manufacturing methods that have been widely used in the past, the yield at the time of manufacturing the toner becomes poor, resulting in an increase in the cost of the toner. .

Therefore, recently, instead of the conventional pulverizing method, a polymerization method, which is advantageous in terms of cost even if the diameter is reduced, has been attracting attention as a method for producing a small diameter toner. This polymerization method includes types such as a suspension polymerization method, an emulsion polymerization method, and a dispersion polymerization method. Among them, the suspension polymerization method is one step ahead in terms of commercialization.

By the way, as the diameter of the toner is reduced, the fluidity of the toner is deteriorated, and a part of the image pattern, particularly a part of the outer shape may be lacked to obtain a dense and uniform image. In the case of a color image, the highlight part becomes rough. Therefore, recently, in order to prevent the deterioration of the fluidity due to the reduction in the diameter of the toner, the shape of the toner has been made spherical. Here, the toner produced by the suspension polymerization method has a spherical shape, but its particle size distribution is broad like the so-called irregular toner having various shapes produced by the conventional pulverizing method. The toner produced by the dispersion polymerization method has a very sharp particle size distribution and a high sphericity, so that a denser and more uniform image can be obtained.

[0005] The case of using a spherical toner as before mentioned is,
The fluidity is better than that of the irregular toner, and good developing characteristics and transfer performance (transfer rate) are obtained. However,
Since the spherical toner has a low rolling resistance, when removing the spherical toner remaining on the surface of the image carrier after transfer with the cleaning blade, the spherical toner slips through between the contact part of the image carrier and the cleaning blade. A large number of streaky toner stains remain on the body surface, resulting in a problem that good cleaning performance cannot be obtained. This cleaning property tends to deteriorate as the particle size of the spherical toner used for development becomes smaller.

Therefore, in order to prevent the cleaning failure of the cleaning blade, a method of developing with a mixture of the spherical toner and the irregular toner has been proposed (for example, JP-A-60-12360). See JP-A-60-12361 and JP-A-60-131547). According to this method, substantially the same cleaning performance as in the case of developing with only the irregular toner can be obtained.

Although not limited to the spherical toner, the average particle size of 3 to 5 containing 0.5 to 5 wt% of a fluidizing agent is used.
In order to prevent cleaning failure of the cleaning blade when using 8 μm toner, a cleaning aid having an average particle diameter of 10 to 30 μm containing 0.05 to 2 wt% of a fluidizing agent is transferred to the surface of the image carrier after transfer. A supply method has been proposed (see, for example, JP-A-4-288554). According to this method, it is possible to efficiently remove the small-diameter toner remaining on the surface of the image carrier with the cleaning blade while obtaining a high-definition and dense image using the small-diameter toner having an average particle diameter of 3 to 8 μm.

[0008]

However, in the method proposed in the above-mentioned JP-A-60-123860, etc.,
Since a mixture of spherical toner and irregular toner is used for development, there is a problem that a dense and uniform image and high transfer performance cannot be obtained as when only spherical toner is used for development. In addition, the above-mentioned JP-A-4-2885
In the method proposed in No. 54, it is necessary to provide a cleaning auxiliary agent supplying device for supplying the cleaning auxiliary agent to the surface of the image carrier and a device for supplying the cleaning auxiliary agent to the cleaning auxiliary agent supplying device. Since it takes time to prepare the supply, it is very disadvantageous in terms of downsizing and cost reduction of the device. In addition, there is the waste of using cleaning aids that are not directly related to image formation.

The present invention has been made under the background described above, and an object thereof is to use a spherical toner to maintain a dense and uniform image, and a cleaning aid on the surface of an image carrier after transfer. It is an object of the present invention to provide an image forming apparatus that can obtain good cleaning performance even if a cleaning blade is used, without providing a cleaning auxiliary agent supplying device for supplying.

[0010]

In order to achieve the above object, the invention of claim 1 is a developing device for developing a latent image on an image carrier, and a visible image on the image carrier as a transfer material. In the image forming apparatus equipped with a transfer device for transferring and a cleaning device for removing the toner remaining on the surface of the image carrier on which the visible image has been transferred by pressing a cleaning blade on the surface of the image carrier, the device, different colors of each
It is composed of a plurality of developing devices containing toner,
Of the toner stored in at least one of the developing units
Black irregular toner, stored in other developing device
The toner is spherical toner, and the visible image is transferred by the transfer device.
The spherical toner remaining on the image carrier is
When reaching the pressing part of the blade, the pressing part is indefinite
As the shaped toner has already arrived and is present, the irregular toner
On the image carrier using a black image developing device containing
The amorphous toner is attached to the.

[0011]

[0012]

According to a second aspect of the invention, a developing device for developing the latent image on the image carrier, a transfer device for transferring the visible image on the image carrier to a transfer material, and a cleaning blade are provided on the surface of the image carrier. And a cleaning device for removing the toner remaining on the surface of the image carrier onto which the visible image has been transferred by pressing the developing device to a spherical toner.
And a developing device containing irregular toner.
Constituted by, the irregular toner develops the tip of the image bearing member surface movement direction of the image area on the image bearing member in the accommodated developing device, the distal end portion of the image region by the developing device accommodating the spherical toner The other part is developed.

According to a third aspect of the invention, in the image forming apparatus according to the first or second aspect , prior to the development of the image area by the developing device containing the spherical toner, the tip of the image area in the moving direction of the surface of the image carrier is formed. The non-image area on the side is developed by a developing device containing the irregular toner.

According to a fourth aspect of the present invention, in the image forming apparatus according to the first, second or third aspect , the width of the developing region of the irregular toner in the direction orthogonal to the moving direction of the surface of the image carrier is pressed by the cleaning blade. It is characterized in that the width is set to be equal to or larger than the width in the orthogonal direction of the developing area of the spherical toner which reaches the portion from behind the developing area of the irregular toner.

According to a fifth aspect of the present invention, in the image forming apparatus according to the third aspect , the non-image area is transferred to the non-image area based on whether or not the image area on the image carrier is developed with only the non-uniform toner. It is characterized in that a control means for controlling whether or not the toner is attached is provided.

According to a sixth aspect of the present invention, in the image forming apparatus according to the third aspect , the amount of spherical toner on the image carrier that reaches the cleaning device is calculated, and the cleaning device reaches the cleaning device according to the calculation result. Control means for controlling the setting of the condition for forming a visible image by the amorphous toner on the image carrier is provided so as to change the amount of the amorphous toner on the image carrier.

According to a seventh aspect of the present invention, in the image forming apparatus according to the sixth aspect , the cleaning is performed based on the number of pixels of the latent image developed with the spherical toner or the writing light amount of each pixel, and the transfer condition of the transfer device. It is characterized in that the amount of spherical toner on the image carrier reaching the apparatus is calculated.

According to an eighth aspect of the invention, in the image forming apparatus according to the seventh aspect , the latent image developed with the spherical toner is written in the surface moving direction of the image carrier as write data of the latent image developed with the irregular toner. It is characterized by using compressed write data.

According to a ninth aspect of the present invention, in the image forming apparatus according to the sixth aspect , based on the developing ability detecting means for detecting the developing ability of the developing device containing the irregular toner, and the detection result of the developing ability detecting means. And a control means for changing the setting of the formation condition of the latent image to be developed with the irregular toner.

According to a tenth aspect of the present invention, in the image forming apparatus according to the sixth aspect , the amount of the irregular toner on the image carrier reaching the cleaning device per unit time and the spherical toner on the image carrier. And the amount of toner reaching the cleaning device per unit time are less than the maximum reachable amount of the cleaning device for cleaning the irregular toner alone, the condition for forming a visible image by the irregular toner. It is characterized by setting.

According to the invention of claim 11 , the latent image on the image carrier is formed.
A developing device for developing and a visible image on the image carrier are transferred to a transfer material.
A transfer device for copying and a cleaning blade are provided on the image carrier.
Image carrier on which the visible image is transferred by pressing on the surface
A cleaning device for removing the toner remaining on the surface,
An intermediate transfer member visible on the image bearing member is transferred, be brought into close contact with the first transfer means for transferring the該顕image to the intermediate transfer member, the the intermediate transfer member and the transfer material by a transfer member Second transfer means for transferring the visible image on the intermediate transfer member to the transfer material by means of the cleaning means, and the intermediate transfer member surface on which the visible image is transferred to the transfer material by pressing the cleaning blade against the surface of the intermediate transfer member. 3. An intermediate transfer member cleaning device for removing the toner remaining on the transfer member, and a transfer member cleaning device for removing the toner remaining on the transfer member surface by pressing a cleaning blade against the transfer member surface. Image forming apparatus, the developing device is a spherical toner
And a developing device containing irregular toner.
Constituted by, the spherical toner prior to development with the accommodated developing device to form a visible image on an image carrier by developing by the developing device accommodating the irregular toner, irregular toner on the image bearing member A part of the visible image of the spherical spherical intermediate transfer member,
A part of the visible image of the irregular toner on the intermediate transfer member is transferred to the transfer member . Claim 12
And a developing device for developing a latent image on an image carrier,
A transfer device that transfers the visible image on the image carrier to the transfer material, and
By pressing the burning blade against the surface of the image bearing member,
The toner remaining on the surface of the image carrier onto which the visible image has been transferred is removed.
The cleaning device to remove and the visible image on the image carrier
The intermediate transfer body to be transferred and the visible image are transferred to the intermediate transfer body.
And a first transfer means for transferring the intermediate transfer member and the transfer material.
Transfer the visible image on the intermediate transfer member by bringing it into close contact with the material
Second transfer means for transferring to material and cleaning blade
By pressing on the surface of the intermediate transfer member, the visible image is transferred.
Toner remaining on the surface of the intermediate transfer body transferred to the copying material is removed.
Intermediate transfer member cleaning device and cleaning
By pressing a blade against the surface of the transfer member, the transfer portion
Transfer member cleaning that removes toner remaining on the material surface
An image forming apparatus including a developing device,
A plurality of developing devices containing toners of different colors.
Of at least one of the plurality of developing devices.
The toner stored in the imager is irregular toner.
The toner accommodated in the developing unit is spherical toner, and the spherical toner
Prior to development by the developing device containing the toner
Image development on the image carrier by developing with a developer containing toner
To form a part of the visible image of the irregular toner on the image carrier.
Amorphous toner transferred onto the intermediate transfer member and on the intermediate transfer member
A part of the visible image of the image is transferred to the transfer member.
It is a thing.

The invention of claim 13 is the invention of claim 11 or 12.
In the image forming apparatus of, a single visible image is formed on the image carrier by the development by the developing device containing the irregular toner,
The transfer conditions in the first transfer unit and the second transfer unit are set so that the visible image is distributed to the image carrier, the intermediate transfer member, and the transfer member. is there.

The invention of claim 14 is the invention of claim 11 or 12.
In the image forming apparatus, the plurality of visible images on the image carrier formed on the image carrier by development by the developing device containing the irregular toner are transferred to the image carrier, the intermediate transfer member, and the transfer member. It is characterized in that the transfer conditions in the first transfer means and the second transfer means are set so as to be distributed to each of the above.

[0025] The invention of claim 15 is based on claims 11, 12, and
In the image forming apparatus 13 or 14 , the amount of the spherical toner on the image bearing member, the intermediate transfer member, and the transfer member reaching each cleaning device is calculated, and the amount of spherical toner reaching each cleaning device is reached according to the calculation result. Conditions for forming a visible image by the irregular toner on the image carrier, and the first transfer means, so as to change the amounts of the irregular toner on the image carrier, the intermediate transfer member, and the transfer member. A control means for controlling the setting of the transfer condition in the second transfer means is provided .

[0026]

According to the image forming apparatus of the present invention, the developing device containing the irregular toner develops a region of the latent image on the image bearing member which does not require a precise and uniform image quality and accommodates the spherical toner. The developing device can develop a region of the latent image which requires a precise and uniform image quality. The visible image formed on the image carrier by this development is transferred to a transfer material by a transfer device. Then, the cleaning blade pressed against the surface of the image carrier of the cleaning device removes the toner remaining on the surface of the image carrier to which the visible image has been transferred. The toner removed from the surface of the image bearing member by the cleaning blade gradually accumulates in the pressing portion of the cleaning blade, and when the toner is accumulated to a certain extent, the toner mass is separated from the pressing portion by dropping due to gravity, and the toner is removed again. Repeat the process of accumulating. Here, even when there is no toner in the pressing portion of the cleaning blade, the irregular toner and the spherical toner remaining on the surface of the image carrier reach the pressing portion, so that both toners are mixed with each other while the image carrier is mixed. Removed from the surface. As described above, since the irregular toner and the spherical toner are mixed at the time of cleaning by the cleaning blade, the rolling resistance of the spherical toner becomes large, and the spherical toner hardly rolls between the cleaning blade and the surface of the image carrier to slip through. .

Here, the irregular toner is a toner having various shapes, such as a toner manufactured by a pulverizing method, and has protrusions, ridges and the like. The particle size of the irregular toner is preferably about 7 μm or more in terms of volume average particle size in order to obtain good cleaning performance with a cleaning blade. The spherical toner is a toner having a high sphericity, such as a spherical toner manufactured by a polymerization method. The particle size of this spherical toner is, for example, 40
When obtaining a fine and uniform image quality in an image of 0 dpi,
The volume average particle diameter is preferably about 7 μm or less.

Particularly, in the image forming apparatus according to the first aspect , the developing device containing the black irregular toner corresponds to the black image which is not often required to have a dense and uniform image quality among the latent images on the image carrier. The developed area is developed, and the area corresponding to the color image having the highlight portion or the halftone portion is often required to have a dense and uniform image quality of the latent image by the developing device containing the color spherical toner. . Here, the black amorphous toner is hardly used for developing the color image.

Further, in the image forming apparatus according to the second aspect of the present invention, only the leading end portion of the image region on the image bearing member in the moving direction of the image bearing member surface is developed with the irregular toner, and the image region other than the leading end portion is developed. By developing the majority with spherical toner, a dense and uniform image quality is obtained in most of the image area.
Further, after the irregular toner remaining at the tip of the cleaning blade of the cleaning device against the image bearing member in the moving direction of the image bearing surface of the image bearing member reaches the image bearing member, The spherical toner remaining on the portion other than the tip portion of the toner reaches. As described above, in cleaning one image area on the image carrier, since the irregular toner that has reached earlier is interposed between the pressing portion of the cleaning blade and the spherical toner, the spherical toner is further absorbed by the cleaning blade and the image carrier. It becomes difficult to slip by rolling between it and the surface.

Further, particularly in the image forming apparatus of the third aspect , since the image area on the image carrier is developed with only the spherical toner, a dense and uniform image quality can be obtained over the entire image area. Further, after the irregular toner adhering to the non-image area on the front end side of the image area in the surface moving direction of the image area reaches the pressing portion of the cleaning blade of the cleaning device against the image area, the image area The spherical toner remaining on the surface reaches. As described above, in cleaning one image area on the image carrier, since the irregular toner that has reached earlier is interposed between the pressing portion of the cleaning blade and the spherical toner, the spherical toner is further absorbed by the cleaning blade and the image carrier. It becomes difficult to slip by rolling between it and the surface.

Particularly, in the image forming apparatus according to the fourth aspect , after the irregular toner reaches the pressing portion of the cleaning blade of the cleaning device against the image carrier, the spherical toner remaining in the image area reaches. To do. Here, the width of the developing area with the irregular toner in the direction orthogonal to the moving direction of the surface of the image carrier is made wider than the width of the developing area with the subsequent spherical toner, and the irregular toner is surely applied to the pressing portion of the cleaning blade. Since the spherical toner remaining in the image area in the intervening state is made to reach the spherical toner, the spherical toner is more reliably rolled between the cleaning blade and the surface of the image carrier and is less likely to slip through.

Further, in the image forming apparatus according to the fifth aspect, in the case where the control means develops the image area on the image carrier with only the irregular toner, based on whether the image area is developed with the irregular toner only. Is controlled so that the irregular toner does not adhere to the non-image area.

Further, in the image forming apparatus according to the sixth aspect of the present invention, the amount of spherical toner on the image carrier reaching the cleaning device is calculated by the control means, and the image carrier reaching the cleaning device is calculated according to the calculation result. In order to change the amount of irregular toner on the body, the setting of conditions for forming a visible image by the irregular toner on the image carrier is controlled so that the irregular toner necessary and sufficient for cleaning the spherical toner is removed by the cleaning device. It reaches the pressing portion of the cleaning blade.
As a result, the irregular toner is mixed with the spherical toner without excess or deficiency.

[0034] Particularly, in an image forming apparatus according to claim 7, the number of pixels or writing light intensity of each pixel of the latent image is developed with spherical toner, and based on the transfer condition of the transfer device, the image bearing reaching the cleaning device By calculating the amount of spherical toner on the body, the irregular toner is mixed with the spherical toner more accurately and without excess or deficiency.

Further, in the image forming apparatus of the eighth aspect , as the writing data of the latent image developed with the irregular toner, the writing data obtained by compressing the latent image developed with the spherical toner in the moving direction of the surface of the image carrier is used. As a result, the ratio of the spherical toner and the amorphous toner mixed with each other is always the same in any portion in the direction orthogonal to the surface moving direction of the image carrier.

Further, in the image forming apparatus of the ninth aspect , the developing ability detecting means detects the developing ability of the developing device containing the irregular toner, and the controlling means detects the developing ability based on the detection result of the developing ability detecting means. Then, the setting of the latent image forming condition for developing with the irregular toner is changed to maintain the developing amount of the irregular toner to an appropriate amount, and the irregular toner is accurately mixed with the spherical toner without excess or deficiency.

Particularly, in the image forming apparatus according to the tenth aspect , the condition for forming a visible image with the irregular toner is set to a predetermined condition, and the irregular toner on the image carrier is fed to the cleaning device per unit time. The sum of the arrival amount and the arrival amount of the spherical toner on the image carrier to the cleaning device per unit time is made smaller than the maximum reachable amount of the cleaning device for the irregular toner alone. The above-mentioned irregular toner has a relatively good cleaning property with respect to the spherical toner, and the sum of the reached amounts of both toners is smaller than the maximum reachable amount of the cleaning device for the irregular toner alone. The excessive toner that exceeds the maximum amount that can be cleaned does not reach the cleaning device.

Particularly, in the image forming apparatus according to the eleventh and twelfth aspects, a visible image is formed on the image carrier by the development by the developing device containing the irregular toner prior to the development by the developing device containing the spherical toner. By forming, transferring a part of the visible image of the irregular toner on the image carrier to the intermediate transfer member, and transferring a part of the visible image of the irregular toner on the intermediate transfer member to the transfer member. When the irregular toner is present between the pressing portion of the cleaning blade of the intermediate transfer member cleaning device and the spherical toner, the irregular toner and the spherical toner remaining on the surface of the intermediate transfer member reach the pressing portion. , Are removed from the surface of the intermediate transfer body while being mixed with each other. Furthermore,
When the irregular toner is present between the pressing portion of the cleaning blade of the transfer member cleaning device and the spherical toner, the irregular toner and the irregular toner and spherical toner remaining on the transfer member surface reach the pressing portion. Then, they are removed from the surface of the transfer member while being mixed with each other.

Further, in the image forming apparatus of the thirteenth aspect , one visible image is formed on the image bearing member by the development by the developing device containing the irregular toner, and one visible image is formed on the image bearing member. Is distributed to the intermediate transfer member and transferred, and a part of the visible image on the intermediate transfer member is further distributed to the transfer member and transferred.

Further, in the image forming apparatus according to the fourteenth aspect , a plurality of visible images are formed on the image bearing member by developing with a developing device containing an irregular toner, and the plurality of visible images are formed on the image bearing member. Are transferred to the intermediate transfer member and transferred, and further some of the visible images on the intermediate transfer member are transferred and transferred to the transfer member.

Further, in the image forming apparatus according to the fifteenth aspect , the amount of spherical toner on the image carrier reaching each cleaning device is calculated by the control means, and each cleaning device is reached according to the calculation result. By controlling the conditions for forming a visible image by the amorphous toner on the image carrier and the setting of the transfer conditions in the first transfer unit and the second transfer unit so as to change the amount of irregular toner on the image carrier. Amorphous toner necessary and sufficient for cleaning the spherical toner is made to reach the pressing portion of the cleaning blade of each cleaning device. As a result, the irregular toner is mixed with the spherical toner without excess or deficiency.

[0042]

Embodiments Embodiments in which the present invention is applied to a full-color copying machine which is an image forming apparatus will be described below. FIG. 1 is a front view showing a schematic configuration of a full-color copying machine according to an embodiment, and FIG. 2 is an enlarged view around a photoconductor / intermediate transfer belt. First, the schematic configuration and operation of a full-color copying machine will be described with reference to FIGS. 1 and 2. A color image reading device (hereinafter, referred to as a color scanner) 1 of this full-color copying machine forms an image of an original 3 on a color sensor 7 through an illumination lamp 4, a mirror group 5, and a lens 6 to form a color of the original. The image information is, for example, blue (Blue,
(Hereinafter referred to as B), green (hereinafter referred to as G),
Red (Red, hereinafter referred to as R) color-separated light is read for each color and converted into an electrical image signal. Then, on the basis of the B, G, and R color-separated image signal intensity levels obtained by the color scanner 1, color conversion processing is performed by an image processing unit (not shown), and black (hereinafter referred to as Bk) and cyan (Cyan, hereinafter C), magenta (Magenta, hereinafter M), and yellow (Yellow, hereinafter Y) color image data are obtained. Then, a color image recording device (hereinafter, referred to as a color printer) 2 described below visualizes Bk, C, M, and Y, and superimposes the toner images obtained thereby to form a four-color full-color image. To do.

The writing optical unit 8 of the color printer 2 converts the color image data from the color scanner 1 into an optical signal, performs optical writing corresponding to the original image, and electrostatically charges the photoconductor 9 as an image carrier. Form a latent image. The photoconductor 9 rotates counterclockwise as indicated by the arrow, and around it, a photoconductor cleaning unit (including a pre-cleaning static eliminator) 10, a static elimination lamp 11, a charger 12,
Potential sensor 13, Bk developing device 14, C developing device 15, M
A developing device 16, a Y developing device 17, an optical sensor 18 for detecting a developing density pattern, an intermediate transfer belt 19 and the like are arranged.

Each of the developing devices of the developing device has a developing sleeve (14a, 15a, 16a, 17a) which rotates by bringing the brush of the developer into contact with the surface of the photoconductor 9 for developing the electrostatic latent image.
And a developing paddle (14b, 15b, 16b, 17b) that rotates to draw up and stir the developer, and a toner concentration sensor (14c, 15c, 16c, 17) of the developer.
c) etc.

Hereinafter, the outline of the copying operation will be described by taking the example of the developing operation order (color image forming order) as Bk, C, M and Y (however, the image forming order is not limited to this). . When the copying operation is started, the color scanner 1 starts reading Bk image data from a predetermined timing, and optical writing by a laser beam and latent image formation start based on the image data (hereinafter, electrostatic image by Bk image data is used. The latent image is referred to as a Bk latent image. C, M, and Y are referred to as a C latent image, an M latent image, and a Y latent image, respectively). In order to enable development from the tip of this Bk latent image, the Bk developing device 1
Before the leading edge of the latent image reaches the developing position of No. 4, the developing sleeve 14a is started to spin the developer, and the Bk latent image is developed with Bk toner. After that, the developing operation of the Bk latent image area is continued, and when the trailing edge of the latent image passes the Bk developing position, the developer on the developing sleeve 14a is quickly cut off to make the developing inoperative state. This is completed at least before the leading edge of the C latent image by the next C image data arrives. The developer is cut off from the developing sleeve 14a.
The direction of rotation is switched to the direction opposite to that during the developing operation.

The Bk toner image formed on the photoconductor 9 is
Photoreceptor 9 of intermediate transfer unit forming part of transfer device
The toner image is transferred onto the surface of the intermediate transfer belt 19 which is driven at a constant speed (hereinafter, toner image transfer from the photoconductor to the intermediate transfer belt is referred to as belt transfer). This belt transfer is performed by the photoreceptor 9
With the intermediate transfer belt 19 in contact with each other, a predetermined bias voltage is applied to the transfer bias rollers 20a and 20b. It should be noted that, on the intermediate transfer belt 19, the Bk, C, M, and Y toner images sequentially formed on the photoconductor 9 are sequentially aligned on the same surface to form a belt transfer image of four-color superimposition. , Perform bulk transfer to transfer paper.

On the side of the photosensitive member 9, the Bk process is followed by the C process, but the C image data reading by the color scanner 1 is started at a predetermined timing, and the C latent image is formed by writing laser light by the image data. C developing device 1
5 starts rotation of the developing sleeve 15a with respect to the developing position after the trailing edge of the previous Bk latent image has passed and before the leading edge of the C latent image has reached, so that the C latent image is converted into C toner. develop. After that, the development of the C latent image area is continued, and when the trailing edge of the latent image passes, the development is inoperative as in the case of the previous Bk developing device. This is also completed before the leading edge of the next M latent image arrives. In addition, regarding each process of M and Y,
The respective image data reading, latent image formation and development operations are carried out in the same manner as the steps Bk and C described above.

In the intermediate transfer belt unit, the intermediate transfer belt 19 is stretched around the driving roller 21, the transfer bias rollers 20a and 20b, and the driven roller group.
The drive is controlled by a drive motor (not shown). The belt cleaning unit 22 as an intermediate transfer member cleaning device is composed of a brush roller 22a, a rubber blade 22b as a cleaning blade, and a contact / separation mechanism 22c from the belt, and after transferring the Bk image of the first color to the belt. While the second, third, and fourth colors are being transferred on the belt, they are separated from the belt surface by the contact / separation mechanism 22c.

The paper transfer unit 23 which constitutes another part of the transfer device includes a paper transfer bias roller 23a as a transfer member and a roller cleaning as a cleaning blade provided in a roller cleaning unit as a transfer member cleaning device. The blade 23b and the belt contact / separation mechanism 23c are included. The bias roller 23a is normally separated from the surface of the intermediate belt 19 but is formed on the surface of the intermediate transfer belt 4a.
When the color superposed image is collectively transferred to the transfer paper 24 as a transfer material, it is pressed by the contact / separation mechanism 23c at a timing, and a predetermined bias voltage is applied to the roller 23a to transfer it to the transfer paper 24. To do. The transfer paper 24 is fed by the paper feed roller 25 and the registration roller 26 at the timing when the leading edge of the four-color superimposed image on the surface of the intermediate transfer belt 19 reaches the paper transfer position.

Then, the transfer paper 24 on which the four-color superposed toner images have been collectively transferred from the surface of the intermediate transfer belt is conveyed to the fixing device 28 by the paper conveying unit 27, and is pressed against the fixing roller 28a controlled to a predetermined temperature. The toner image is melted and fixed by the roller 28b and carried out to the copy tray 29 to obtain a full color copy.

The photosensitive member 9 after the belt transfer is processed by a photosensitive member cleaning unit 10 as a cleaning device.
(Pre-cleaning static eliminator 10a, brush roller 10b,
The surface is cleaned with a rubber blade 10c) as a cleaning blade, and the charge is uniformly discharged with the charge removing lamp 11. In addition, the intermediate transfer belt 19 after the toner image is transferred onto the transfer paper 24 is cleaned by the cleaning unit 22.
Is pressed again by the contact / separation mechanism 22c to clean the surface.

At the time of repeat copy, the color scanner 1
The operation and the image formation on the photosensitive member 9 proceed to the second Bk (first color) image process at a predetermined timing after the first Y (fourth color) image process. Further, in the intermediate transfer belt 19, the second Bk toner image is formed in the area where the surface is cleaned by the cleaning unit 22, following the batch transfer process of the first four-color superimposed image onto the transfer paper. Allow the belt to be transferred. After that, the same operation as the first sheet is performed.

The transfer paper cassettes 30, 31, 32,
The reference numeral 33 stores transfer sheets of various sizes, which are fed and conveyed in the direction of the registration rollers 26 at a timing from a storage cassette of size sheets designated by an operation panel (not shown). Reference numeral 34 is a manual paper feed tray for OHP paper or thick paper.

The above is the description of the copy mode in which four full colors are obtained, but in the case of the three-color copy mode and the two-color copy mode, the same operation as described above is performed for the designated color and the number of times. It will be. In the single-color copy mode, until the predetermined number of sheets are finished, only the developing device of that color is in a developing operation (agent standing) state, and the intermediate transfer belt 19 remains in contact with the surface of the photoreceptor 9. Drives in the forward direction at a constant speed, and the belt cleaner 22
The copy operation is performed in the state of being in contact with 9 .

Next, the developer used in the full-color copying machine of this embodiment will be described. For each of the developing devices, a two-component type developer including a toner and a carrier that is magnetic particles was used. As the black toner accommodated in the Bk developing device 14, irregular toner is used, and the C developing devices 15 and M for color are used.
The cyan toner, magenta toner, and yellow toner contained in the developing device 16 and the Y developing device 17, respectively, are
Spherical toner was used.

The above irregular toner was manufactured by the following method. First, 5 parts by weight of carbon black is added to a polyester resin (the weight of the resin is 100)
And a salicylic acid derivative zinc salt as a charge control agent (CCA) are mixed, and the mixture is mixed with a two-roll kneader at 100 ° C. for 30 minutes.
Knead for minutes. Then, this kneaded material is roughly crushed and then finely crushed by a jet stream crusher of a collision plate system.
Then, the finely pulverized material is classified by a turbo classifier to obtain a powder having a volume average particle diameter of 7.5 μm. The amorphous toner can be obtained by adding 1 part by weight of coarse aqueous silica fine powder to this powder and mixing them with a super mixer.

The spherical toner was manufactured by the following method proposed by the applicant in Japanese Patent Publication No. 6-17373. First, a polymer dispersant soluble in the hydrophilic liquid is added to the hydrophilic organic liquid in the range of 0.1 to 5% by weight. One or two kinds of polymers, which are dissolved in the hydrophilic organic liquid to which the polymer dispersant is added but are dissolved in the hydrophilic organic liquid, but are swollen or hardly dissolved in the hydrophilic organic liquid. The above vinyl monomer is added to the polymer dispersant in an amount of 20 times or less and polymerized with stirring. Particles having an average particle diameter of 1 to 100 μm obtained by this polymerization and having a particle diameter distribution suppressed to ± 25% or less are 95% by weight.
% Of the resin particles having a narrow particle size distribution are dispersed in an organic solvent that does not dissolve the resin particles, and the dye is dissolved in the solvent before or after the resin particles are dispersed. The spherical toner can be obtained by infiltrating the resin particles into the resin particles for coloring and then removing the solvent.

Here, as the dye, a dye having a relationship between the solubility in the organic solvent (D ₁ ) and the solubility of the resin particles in the resin (D ₂ ) is D ₁ / D ₂ ≤0.5 is used. . As a dye for magenta toner, oil red 5B (manufactured by Orient Chemical Co., Ltd., D ₁ / D ₂ ≦
0.14), Solvent Yellow 6 as a dye for yellow toner, and Oil Blue II N (manufactured by Orient Chemical Co., D ₁ / D ₂ ≦ 0.
02) was used. The hydrophilic organic liquid is methanol, the polymer dispersant is polyvinylpyrrolidone, the vinyl monomer is styrene, the polymerization initiator is azobisisobutyronitrile, and the charge control agent is 3-5. Zinc-di-t-butylsalicylate was used respectively.

The carrier of the above-mentioned developer has a volume average particle diameter of 50 μm, a magnetic characteristic of 65 emu / g, and a volume resistivity of 10 ⁹ Ω.
cm silicone coated ferrite particles were used. Then, the irregular toner is mixed with this carrier so that the weight ratio of the toner to the weight of the developer is 5%,
Bk developer was adjusted. Similarly, the C, M, and Y spherical toners having the same weight ratio of 5% were mixed with the above carrier to prepare C developer, M developer, and Y developer.

Comparative Example First, as a comparative example with respect to the specific example of the present embodiment, a single color continuous copy was carried out using only the C toner, which is the spherical toner, in the full-color copying machine having the above-mentioned structure. As a result, the copy image was obtained with a fine and uniform image quality, but many streaky toner stains appeared due to poor cleaning from the few copies, and the width and level of the stain increased the number of copies. It gradually got worse with it. Similarly, the results were the same when single-color continuous copying was performed using only spherical toners M toner and Y toner. On the other hand, when single-color continuous copying was performed using only the Bk toner, which is an irregular toner, toner contamination due to poor cleaning did not occur.

Specific Example 1 Next, as a specific example of the present embodiment, the Bk toner which is the irregular toner and the C, M, and Y toners which are spherical toners are used in the full-color copying machine having the above-described structure. Continuous copying was performed in full color mode to form a color copy image. As a result, a dense and uniform full-color image was obtained. Further, the interval (number of copies) where the toner stain is generated due to defective cleaning was slightly extended as compared with the case of the comparative example, but similar toner stain was generated. The toner stains are concentrated on a portion of the image forming pattern of each color obtained by color-separating the original document, in which the Bk toner is not developed or the development by the Bk toner is small, so that the irregular toner in the cleaning area is formed. It was found that the presence of the Bk toner, which is the above, affects the cleaning property of the cleaning blade. Further, from this result, it is a necessary condition for obtaining good cleaning properties that the Bk toner, which is an irregular toner, reaches the cleaning region at least before the color toner, which is a spherical toner. all right.

Specific Example 2 Next, as a specific example of this embodiment, C toner (single color), which is a spherical toner in the above comparative example.
Before developing the image area, a belt-shaped latent image pattern having the maximum image forming width of the system is formed in the non-image portion in front of the tip of the latent image pattern with respect to C in the direction orthogonal to the moving direction of the photoreceptor surface. The latent image pattern was developed with Bk toner, which is an irregular toner, and Bk toner was attached. As a result, a dense and uniform C color image can be obtained, and
There was no toner stain due to poor cleaning, and good images could be maintained.

Specific Example 3 Next, in the same manner as in Specific Example 2, the Bk toner, which is an irregular toner, is adhered in a band shape to the non-image area before the C, M, and Y image areas. Then, continuous copying was performed. As a result, a fine and uniform color image was obtained without causing stain due to poor cleaning, and a good image could be continuously maintained without occurrence of toner stain due to poor cleaning.

In the above embodiment, when performing a copying operation in which the Bk toner which is the irregular toner is attached to the non-image area before the image area, only the Bk toner which is the irregular toner is used for the development of the image area. In the case of using, the good cleaning property can be obtained by controlling not to develop the Bk toner on the non-image area. In this case, wasteful consumption of Bk toner can be prevented.

In the above embodiment, the ratio of the amount of spherical toner reaching the photoconductor cleaning unit 10 to the amount of irregular toner (spherical toner amount / amorphous toner amount × 100)
The relationship between (%)) and the cleaning property is as shown in FIG. 3, for example. As can be seen from FIG. 3, if the ratio is not more than a certain amount, the photoconductor cleaning unit 10 cannot obtain sufficient cleaning property. The ratio of sufficient cleaning property is the cleaning property for spherical toner that changes depending on the sphericity and particle size of spherical toner, and the cleaning property for irregular toner that also changes according to sphericity and particle size of irregular toner. It depends on the balance with. Further, the cleaning property of the photoconductor cleaning unit 10 naturally varies not only with the ratio but also with the amount of toner reaching the cleaning unit 10.

Therefore, in the above embodiment, when the Bk toner, which is an irregular toner, is adhered in a band shape to the non-image area before the C, M, and Y image areas using the spherical toner, the optimum cleaning property is obtained. C, so that
The developing amount of the Bk irregular toner may be controlled as follows according to the developing amount of each of the M and Y spherical toners. FIG. 4 is a block diagram of an image processing system of the full color copying machine and a control unit 50 as a control means. As described above, the color image information of the original 3 is read by the color scanner 1 and sent to the IPU (Image Processing Unit) 40. In this IPU 40, after performing scanner γ correction, masking, UCR / UCA (background removal / blackening), printer γ correction, etc., color image information is C, M, Y, Bk printer signals (latent image writing). Data) to the color printer 2. From this printer signal, the number of pixels for each of Bk, C, M, and Y development and laser power data (writing light amount) can be known. Further, the printer signal compressed in the sub-scanning direction (direction orthogonal to the moving direction of the surface of the photoconductor) is the original C, M, Y,
The Bk printer signal can be easily obtained by passing it through an appropriate spatial filter. In addition, the control unit 5
Reference numeral 0 is composed of a CPU 51, a RAM 52, a ROM 53, an I / O interface 54 and the like. This control unit 5
The I / O interface 54 of 0 is connected to the printer signal generation circuit of the IPU 40 via the spatial filter for data compression and the image memory for pixel count, and is connected to the color printer 2.

FIGS. 5A and 5B are examples of control flows. In the control flow of FIG. 5A, after the original is scanned and read, the total number of pixels (QG) of the color image formed with spherical toner is counted (steps 1 and 2). Then, this QG value is converted into the total number of pixels (FG) of the image formed with the irregular toner (step 3). Here, FIG. 6A shows the total number of pixels (Q
FIG. 9 is a characteristic diagram showing the relationship between G) and the total number of pixels (FG) of irregular toner, where the transfer rate of spherical toner is T (0 ≦ T ≦ 1).
Then, the total number of pixels (FG) of irregular toner is
It can be obtained by the conversion formula shown in.

[Formula 1] FG = QG · (1-T) · α

When the parameter α = 1 in the conversion formula of the above equation 1, spherical toner is used as the photoconductor cleaning unit 1.
This means that the amount of toner that reaches 0 is the same as the amount of amorphous toner that is attached (developed). The value of the parameter α can be optimally determined by the cleaning conditions for each toner (photoconductor surface moving speed, sphericity of spherical toner and irregular toner, pretreatment conditions for cleaning PPC, etc.).

To obtain the actual image data of the irregular toner from the total pixel number (FG) of the irregular toner, for example, the value of FG is divided by the number of pixels (LG) of one line in the main scanning direction (LG). Step 4). When a remainder is generated in the calculation result of FG / LG, the remainder may be rounded off or the remainder may be written as it is. And
A latent image is written with an appropriate laser power for the calculated line and image formation is executed (step 5).

Further, in the control flow of FIG. 5B, after the original is scanned and read, the integrated amount (QS) of the write data for each pixel of the color image formed by the spherical toner is formed.
D) is calculated (steps 1 and 2). And this QS
From the value of D, the integral amount (FSD) of the write data for each image formed with the irregular toner is calculated (step 3).
Here, FIG. 6B is a characteristic diagram showing the relationship between the integral value (QSD) of the write data for each pixel of the spherical toner and the integral value (FSD) of the write data for each pixel of the irregular toner. As in the case of FG, the integral value (FSD) of the write data for each pixel of the irregular toner is given by
It can be calculated by the formula shown in.

[Formula 2] FSD = QSD · (T-1) · α

In order to obtain the actual image data of the irregular toner from the integrated value (FSD) of the writing data for each pixel of the irregular toner, for example, the value of FSD is set to 1 in the main scanning direction.
It is calculated by dividing by the number of pixels (LG) in the line (step 4). Then, a latent image is written with an appropriate laser power for the calculated line and image formation is executed (step 5).

As in this modification, by controlling the developing amount of the irregular toner according to the developing amount of the spherical toner, the irregular toner necessary and sufficient for cleaning the spherical toner is supplied to the photoconductor cleaning unit 10. Rubber blade 1
Since the irregular toner can be mixed with the spherical toner without excess or deficiency by reaching the pressing portion of 0c, the optimum cleaning property can be obtained.

In the modified example using the control flow of FIG. 5, the image data of the latent image developed with the spherical toner of FIG. 7A is transferred in the sub-scanning direction (photosensitive member surface moving direction; arrow B in the drawing).
The image data compressed in the direction (see FIG. 7B) may be used as the image data of the latent image developed with the irregular toner.
The arrow A direction in the drawing is the main scanning direction. In this case,
Since the ratio of the spherical toner and the irregular toner that are mixed with each other is always the same in any part in the main scanning direction, the optimum cleaning property is obtained even when the adhesion amount of the spherical toner in the main scanning direction is distributed. can get.

Further, in the above modification, FG and FS
The value of D may be calculated using the calculation formula shown in the following Expression 3. The parameter β in this calculation formula has the relationship shown in FIG. 8 with the developing ability of the developing device for the irregular toner, and using this parameter β, even if the developing ability changes, the adhering amount of the irregular toner Has been corrected so that it does not become more than necessary. In addition, as a method of measuring the developing ability, the photosensitive member 9 is used.
Known techniques such as a method of measuring the reflection density of the toner image developed above can be adopted.

[Formula 3] FG = QG · (1-T) · α / β FSD = QSD ・ (T-1) ・ α / β

Further, in the above modification, in order to prevent the occurrence of cleaning failure due to excessive toner reaching the cleaning device, cleaning of the irregular toner per unit area and unit time on the image carrier is performed. The sum of the arrival amount to the device and the arrival amount to the cleaning device of the spherical toner per unit area and unit time on the image carrier is smaller than the maximum cleaning amount of the cleaning device for the irregular toner alone. May be controlled as follows. An example of this control flow is shown in FIG. First,
The irregular toner amount (FM) reaching the photoconductor cleaning unit 10 is set to a constant value as the above-mentioned total number of pixels (FG) or the integral amount (FSD) of the write data for each pixel as shown in the following formula 4. It is obtained by multiplying by the coefficient (step 1). The values of K1 and K2 in the equation are coefficients.

[Equation 4] FM = FG · K1 FM = FSD ・ K2

Further, the spherical toner amount (QM) reaching the photoconductor cleaning unit 10 is expressed by the above-mentioned total number of pixels (QG) or the integrated amount of write data (QSD) for each pixel as shown in the following equation 5. ) To a constant coefficient (K3 and K
It is obtained by multiplying by 4) (step 2). Here, the coefficients K1 to K4 used in the equations 4 and 5 are experimentally obtained from the relationship between the actual toner adhesion amount and the pixel data (QG, QSD). Next, the value of FM and the sum of QM are compared with the maximum amount Mmax of the irregular toner that can be cleaned by the photoconductor cleaning unit 10, and Mmax ≧ F
Only in the case of M + QM, image formation is performed using the irregular toner and the spherical toner (steps 3 to 5).

[Equation 5] QM = QG · K3 QM = QSD ・ K4

In the above embodiment, the cleaning performance of the photoconductor cleaning unit 10 is improved. In addition to the cleaning unit 10, the belt cleaning for cleaning the surface of the intermediate transfer belt 19 with the rubber blade 22b. In order to improve the cleaning performance of the unit 22 and the roller cleaning unit that cleans the surface of the paper transfer bias roller 23a with the roller cleaning blade 23b, the arrival timing of the irregular toner to each cleaning unit may be controlled. . An example of this control is shown in FIG.
Shown in. First, in order to allow the irregular toner to reach each cleaning unit prior to the spherical toner, a control pattern (hereinafter referred to as a control pattern) for developing with the irregular toner before forming a latent image to be developed with the spherical toner. )
Is formed in a non-image area different from the image area to be developed with spherical toner, and the latent image of the control pattern is developed by a developing device (Bk developing device 14 in the above embodiment) containing an irregular toner (step 1). , 2). Next, a latent image to be developed with a spherical toner is formed, and the latent image is developed with a developing device containing the spherical toner (C developing device 15, M developing device 16 or Y developing device 17 in the above embodiment) (step 3, 4). Next, the belt transfer bias Tb is set to Tbo as shown in FIG.
To Tbf, and the toner image of the irregular toner corresponding to the control pattern is transferred to the intermediate transfer belt 19 (steps 5 and 6). Next, the belt transfer bias T
b is switched from Tbf to Tbo, and the toner image of spherical toner is transferred to the intermediate transfer belt 19 (step 7,
8). After that, the residual toner on the photoconductor 9 reaches the pressing portion of the rubber blade 10c of the photoconductor cleaning unit 10 in the order of the irregular toner and the spherical toner, and the surface of the photoconductor 9 is cleaned (step 9). The operations from step 1 to step 9 are repeated until the image formation with all spherical toners is completed (step 10).
When the color-separated image of the original is developed with an irregular toner, a latent image of the control pattern for the irregular toner is formed in the non-image area prior to the image, and the latent image is formed. The step of developing with an irregular toner may be omitted .

Here, from the characteristic diagram showing the relationship between the belt transfer bias Tb and the transfer rate to the intermediate transfer belt 19 in FIG. 11A, it is understood that the transfer rate of the irregular toner is inferior to that of the spherical toner. . In FIG. 11A, Tb
o is the belt transfer bias of the optimum transfer condition for the spherical toner. On the other hand, Tbf is set to a value outside the belt transfer bias Tbfo which is the optimum transfer condition for irregular toner. That is, the transfer condition for supplying the irregular toner not used for forming the copy image to each cleaning unit is the optimum transfer condition (T for distributing the irregular toner to the photoconductor 9 and the intermediate transfer belt 19 in a necessary amount).
It does not need to be b = Tbfo) and can be set freely.
In the case of this modification, for example, the belt transfer bias Tbf is set so that the belt transfer rate is 40%, whereby 40% of the irregular toner is transferred to the intermediate transfer belt 19, and the remaining 60% of the toner is not transferred. The fixed toner is supplied to the photoconductor cleaning unit 10. Further, in this modification, the value is set to be smaller than the optimum transfer bias Tbfo, but it may be set to a value larger than Tbfo.

When all the toner images have been transferred onto the intermediate transfer belt 19, the paper transfer bias Pb is switched from Pbo to Pbf as shown in FIG. The toner image of (1) is transferred to the paper transfer bias roller 23a (step 1
1, 12). Next, the paper transfer bias Pb is set to Pbf.
To Pbo, and the toner image of the spherical toner on the intermediate transfer belt 19 is transferred to the transfer paper (step 13,
14). Then, the belt cleaning unit 22
On the pressing portion of the rubber blade 22b of the intermediate transfer belt 19
The upper residual toner reaches the irregular toner and the spherical toner in this order, and the surface of the intermediate transfer belt 19 is cleaned (step 15). Further, in the pressing portion of the roller cleaning blade 23b of the roller cleaning unit,
Since the toner on the paper transfer bias roller 23a arrives in the order of the irregular toner and the spherical toner and the surface of the paper transfer bias roller 23a is cleaned (step 15), if the spherical toner adheres to the paper transfer bias roller 23a ( Even if it is transferred, cleaning failure does not occur.

Here, from the characteristic diagram showing the relationship between the paper transfer bias Pb and the transfer rate onto the transfer sheet in FIG. 11B, it can be seen that the transfer rate of the irregular toner is inferior to that of the spherical toner. In FIG. 11B, Pbo is the belt transfer bias of the optimum transfer condition for the spherical toner. On the other hand, Pbf is set to a value deviating from the paper transfer bias Pbfo which is the optimum transfer condition for the irregular toner as in the case of the belt transfer bias Tb. Paper transfer bias P for this irregular toner
bf distributes the irregular toner on the intermediate transfer belt 19 to which 40% of the irregular toner on the photoconductor 9 is transferred, to the surface of the intermediate transfer belt 19 and the surface of the paper transfer bias roller 23. It is appropriately adjusted so as to supply.

Further, in the modification shown in the control flow of FIG. 10, the irregular toner necessary and sufficient for cleaning the spherical toner is made to reach the pressing portion of the blade of each cleaning unit, and the irregular toner is changed to the spherical toner. The amount of development of the irregular toner may be set in accordance with the amount of development of the spherical toner to be developed immediately after the irregular toner so as to obtain the optimum cleaning property by mixing just enough. As this setting method, the same methods as described using the above formulas 1 to 5 can be adopted, and description thereof will be omitted.

Further, in the modified example shown in the control flow of FIG. 10, in order to make the irregular toner reach each cleaning unit prior to the spherical toner, the tip side of the image area of the spherical toner in the moving direction of the tourist object surface side. In the non-image area of
Although only one latent image of the control pattern for the irregular toner is formed, a latent image of a different control pattern may be formed for each cleaning unit so as to be formed in the non-image area. A timing chart of this control is shown in FIG. First, after forming three control pattern latent images for irregular toner on the photoconductor 9, a latent image corresponding to the original image for spherical toner is formed. The developing device containing the irregular toner (Bk developing device 14 in the above embodiment) is
Development is performed when the latent image of the control pattern reaches the developing position, and after the development is completed, the latent image for spherical toner is not developed so as not to be developed. Next, the developing device containing the spherical toner (C developing device 15, M developing device 16 or Y developing device 17 in the above-described embodiment) is made ready for development only when the latent image for the spherical toner reaches the developing position. When the development with the spherical toner is completed, the non-development state is established.

The intermediate transfer belt 19 has the photosensitive member 9 before the irregular toner image of the control pattern reaches the transfer area.
Is in a non-intermediate transfer state in which the control pattern does not come into contact with the photosensitive member 9 after the control pattern's irregular toner image has passed through the transfer region and shortly before the control pattern's irregular toner image reaches the transfer region. After the control pattern and the toner image of the spherical toner are transferred onto the intermediate transfer belt 19, the control pattern and the toner image are separated from the photoconductor 9 to be in a non-transfer state. After the intermediate transfer step, the irregular toner image of the control pattern, the transfer residual toner of the toner image of the control pattern, and the transfer residual toner of the spherical toner image adhered on the photoconductor 9 are cleaned in this order. Reach Unit 10.

The paper transfer bias roller 23a is in a non-transfer state in which transfer onto the transfer paper is not performed until the transfer residual toner of the spherical toner image on the intermediate transfer belt 19 reaches the paper transfer area. After the irregular toner image of the control pattern on 10 passes through the transfer area and shortly before the irregular toner image of the control pattern reaches the transfer area, it contacts the intermediate transfer belt 19 to complete the transfer of the spherical toner image. Then it returns to the non-transfer state. Here, since the size of the transfer paper (the length of the paper transfer bias roller 23a in the surface moving direction) corresponds to the length of the spherical toner image, the spherical toner image is transferred to the transfer paper, but the intermediate transfer belt is used. The irregular toner image of the control pattern on 19 reaches the roller cleaning unit without being transferred to the transfer paper. Further, the toner image of the control pattern and the transfer residual toner of the control pattern are present on the intermediate transfer belt 19 after the paper transfer, and reach the belt cleaning unit 22 in this order. The amount of irregular toner supplied to each cleaning unit can be changed by changing the latent image forming conditions (latent image potential, etc.) of each control pattern, the size of the control pattern, the transfer rate of the toner image of the control pattern, etc. It can be set freely. Also in the modification described with reference to the timing chart of FIG. 12, the irregular toner necessary and sufficient for cleaning the spherical toner is made to reach the pressing portion of the blade of each cleaning unit, and the irregular toner is changed to the spherical toner. The amount of development of the irregular toner may be set in accordance with the amount of development of the spherical toner to be developed immediately after the irregular toner so as to obtain the optimum cleaning property by mixing just enough.
As this setting method, the same methods as described using the above formulas 1 to 5 can be adopted, and description thereof will be omitted.

In the above embodiment, the case of the full-color copying machine in which four developing devices are arranged around the photoconductor 9 has been described. However, the present invention has two or three photoconductors around the photoconductor 9.
The present invention can be applied to an image forming apparatus provided with one or five or more developing devices, and similar effects can be obtained. Also,
The present invention is not limited to a full-color copying machine, but can be applied to other image forming apparatuses such as printers and fax machines, and similar effects can be obtained.

Further, in the above-described embodiment, the one provided with the developing device using the two-component type developer consisting of the carrier and the toner has been described, but the present invention does not have the carrier.
The present invention can be applied to an image forming apparatus equipped with a developing device using a component type developer, and the same effect can be obtained.

[0087]

According to the first and second aspects of the present invention, the developing device containing the irregular toner develops the area of the latent image on the image bearing member, which is not required to be dense and uniform in image quality, to obtain the spherical toner. The developing device accommodates the latent image in a region where a dense and uniform image quality is required, and the image formed on the image carrier by this development is transferred to a transfer material by a transfer device. Thus, there is an effect that a dense and uniform image can be obtained. In the cleaning of the surface of the image carrier by the cleaning blade of the cleaning device after the transfer is completed, the irregular toner and the spherical toner remaining on the surface of the image carrier are pressed against the pressing portion of the cleaning blade on the surface of the image carrier. Is reached, and the amorphous toner and the spherical toner are mixed and removed from the surface of the image carrier. This increases the rolling resistance of the spherical toner and makes it difficult for the spherical toner to roll between the cleaning blade and the surface of the image bearing member to slip through.Therefore, when the cleaning blade is used without providing a cleaning aid supply device, The effect is that good cleaning performance can be obtained for the spherical toner remaining on the surface of the image carrier.

[0088]

[0089] In particular, according to the second aspect of the invention, only the tip portion of the image bearing member surface movement direction of the image area on the image bearing member is developed with irregular toner, large in the image region other than the tip portion Since the portion is developed with the spherical toner, there is an effect that a dense and uniform image quality can be obtained in most of the image area.
Further, in cleaning one image area on the image bearing member, the irregular toner which has reached earlier is interposed between the pressing portion of the cleaning blade on the surface of the image bearing member and the spherical toner, and the spherical toner and the cleaning blade form an image. Since it is hard to slip through the surface of the carrier to slip through, it is possible to obtain a better cleaning performance for the spherical toner remaining on the surface of the image carrier.

Further, according to the invention of claim 3 , the image area on the image carrier is developed with only the spherical toner, so that the dense and uniform image quality can be obtained over the entire image area. is there. Further, in the cleaning of one image area on the image carrier, the irregular toner that has reached first is interposed between the pressing portion of the cleaning and the spherical toner, and the spherical toner is further separated between the cleaning blade and the surface of the image carrier. Since it is difficult for the toner to slip through and slip through, there is an effect that a better cleaning performance can be obtained for the spherical toner remaining on the surface of the image carrier.

According to the fourth aspect of the present invention, the width of the developing area formed by the irregular toner in the direction perpendicular to the moving direction of the image carrier surface is made wider than the width of the developing area formed by the subsequent spherical toner. Since the spherical toner remaining in the image area reaches the contact area with the irregular toner intervening, the spherical toner is more reliably rolled between the cleaning blade and the surface of the image carrier and is less likely to slip through. Therefore, for the spherical toner remaining on the surface of the image carrier,
Further, there is an effect that a better cleaning performance can be obtained.

In particular, according to the invention of claim 5 , the non-image area is developed in the case of developing only the irregular toner based on whether the image area on the image carrier is developed with the irregular toner only. Since the irregular toner is controlled so as not to adhere to the irregular toner, the irregular toner is not wasted.

Further, in particular, according to the invention of claim 6 , the control means calculates the amount of spherical toner on the image carrier which reaches the cleaning device, and the image carrier which reaches the cleaning device is calculated according to the calculation result. By controlling the setting of the condition for forming a visible image by the irregular toner on the image carrier so as to change the amount of irregular toner above, the irregular toner becomes spherical toner at the pressing portion of the cleaning blade of the cleaning device. There is an effect that an optimum cleaning property can be obtained by mixing just enough.

Further, in particular, according to the invention of claim 7 , the image carrier that reaches the cleaning device based on the number of pixels of the latent image to be developed with the spherical toner or the writing light amount of each pixel, and the transfer condition of the transfer device. By calculating the upper spherical toner amount, there is an effect that the irregular toner is accurately mixed with the spherical toner without excess and deficiency, and further the optimum cleaning property is obtained.

According to the eighth aspect of the invention, the write data obtained by compressing the latent image developed with the spherical toner in the moving direction of the surface of the image carrier is used as the write data for the latent image developed with the irregular toner. As a result, the ratio of the spherical toner and the amorphous toner mixed with each other is always the same in any part in the direction orthogonal to the surface movement direction of the image carrier, so that the spherical toner is mixed in the direction orthogonal to the surface movement direction of the image carrier. Even if the toner adhesion amount is distributed, there is an effect that the optimum cleaning property is obtained.

Further, according to the invention of claim 9 , the developing capacity detecting means detects the developing capacity of the developing device containing the irregular toner, and the controlling means detects the developing capacity based on the detection result of the developing capacity detecting means. , By changing the setting of latent image formation conditions for developing with irregular toner, the development amount of irregular toner is maintained at an appropriate amount, and irregular toner is accurately mixed with spherical toner without excess or deficiency. Even if the developing capacity of the developing device containing the toner changes, it is possible to obtain the optimum cleaning property.

According to the tenth aspect of the invention, the condition for forming a visible image with the irregular toner is set to a predetermined condition, and the irregular toner on the image carrier reaches the cleaning device per unit time. Amount, and the amount of the spherical toner on the image carrier that reaches the cleaning device per unit time from the maximum reachable amount of the cleaning device for the irregular toner alone that provides relatively good cleaning performance. By reducing the amount, too much toner that exceeds the maximum amount that can be cleaned does not reach the cleaning device, and the effect of cleaning failure can be prevented in advance.

According to the eleventh and twelfth aspects of the present invention, prior to the development by the developing device containing the spherical toner, the developing device containing the irregular toner forms a visible image on the image bearing member. Then, a part of the visible image of the irregular toner on the image carrier is transferred to the intermediate transfer member, and a part of the visible image of the irregular toner on the intermediate transfer member is transferred to the transfer member. In addition to the cleaning device for the image carrier, the intermediate transfer member cleaning device and the transfer member cleaning device are provided with the irregular toner between the pressing portion of the cleaning blade and the spherical toner. The irregular toner and the spherical toner remaining on the surface and the transfer member reach the pressing portion and are removed from the surface of the intermediate transfer body while being mixed with each other. There is an effect that ring is obtained.

According to the thirteenth aspect of the present invention, one visible image is formed on the image carrier by the development by the developing device containing the irregular toner, and one visible image on the image carrier is formed. Since a part of the visible image on the intermediate transfer member is further distributed and transferred to a transfer member, a single visible image of the irregular toner is formed. The effect is that irregular toner can be supplied to each cleaning device.

According to the fourteenth aspect of the present invention, a plurality of visible images are formed on the image bearing member by developing with the developing device containing the irregular toner, and a plurality of visible images are formed on the image bearing member. Some of them are transferred to the intermediate transfer member and transferred, and some of the visible images on the intermediate transfer member are further transferred to the transfer member, so that by changing the conditions for forming the image with each irregular toner, There is an effect that the supply amount of the irregular toner to each cleaning device can be set more freely.

Further, according to the invention of claim 15 , the control means calculates the amount of spherical toner on the image carrier reaching each cleaning device, and the image reaching each cleaning device is calculated according to the calculation result. By controlling the conditions for forming a visible image by the amorphous toner on the image carrier and the setting of the transfer conditions in the first transfer unit and the second transfer unit so as to change the amount of irregular toner on the carrier. There is an effect that the irregular toner is mixed with the spherical toner in an appropriate amount at the pressing portion of the cleaning blade of each cleaning device to obtain the optimum cleaning property.

[Brief description of drawings]

FIG. 1 is a front view showing a schematic configuration of a full-color copying machine according to an embodiment.

FIG. 2 is an enlarged view around a photoconductor and an intermediate transfer belt of the full-color copying machine.

FIG. 3 is a characteristic diagram showing the relationship between the cleaning property and the ratio of spherical toner and irregular toner reaching the cleaning unit of the full-color copying machine.

FIG. 4 is a block diagram of an image processing system of the full-color copying machine.

5A and 5B are flowcharts of a control example of a full-color copying machine according to a modified example.

FIG. 6A is a characteristic diagram showing the relationship between the total number of pixels (QG) of spherical toner and the total number of pixels (FG) of irregular toner.
(B) is a characteristic diagram showing the relationship between the pixel data integration amount (QSD) of spherical toner and the pixel data integration amount (FSD) of irregular toner.

FIG. 7A is an explanatory diagram of a latent image pattern developed with spherical toner. FIG. 6B is an explanatory diagram of a latent image pattern developed with an irregular toner.

FIG. 8 is a characteristic diagram showing the relationship between the developing ability of irregular toner and the correction parameter β.

FIG. 9 is a flowchart of a control example of a full-color copying machine according to another modification.

FIG. 10 is a flowchart of a control example of a full-color copying machine according to another modification.

FIG. 11A is a characteristic diagram showing a relationship between a belt transfer bias (Tb) and a belt transfer rate. FIG. 6B is a characteristic diagram showing the relationship between the paper transfer bias (Pb) and the paper transfer rate.

FIG. 12 is a timing chart of a control example of a full-color copying machine according to another modification.

[Explanation of symbols]

1 color scanner 2 color printer 9 photoconductor 10 Photoconductor cleaning unit 10c rubber blade 14 Bk developing device 15 C developing device 16M developing device 17 Y developing device

Front page continued (72) Inventor Makoto Osaki 1-3-6 Nakamagome, Ota-ku, Tokyo Stock company Ricoh (72) Yushi Yamashita 1-3-6 Nakamagome, Ota-ku, Tokyo Stock company In Ricoh (72) Inventor Souta Fujimori 1-3-6 Nakamagome, Ota-ku, Tokyo Stock company Ricoh (72) Inventor Yasunori Kawaishi 1-3-3 Nakamagome, Ota-ku, Tokyo Ricoh (56) References JP-A-5-2309 (JP, A) JP-A-5-27549 (JP, A) JP-A-1-126670 (JP, A) JP-A-5-224497 (JP, A) JP-A 2-148084 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G03G 15/01-15/01 117 G03G 21/00 370 G03G 21/10 G03G 15/16 G03G 15/08-15/095

Claims (15)

(57) [Claims] 1. A developing device for developing a latent image on an image carrier,
A transfer device that transfers the visible image on the image carrier to a transfer material, and a cleaning device that presses a cleaning blade against the surface of the image carrier to remove the toner remaining on the surface of the image carrier to which the visible image has been transferred. An image forming apparatus including a developing device, the developing device is configured by a plurality of developing devices that respectively store toners of different colors, and the toner stored in at least one of the plurality of developing devices is black. The toner contained in the other developing device is spherical toner, and the spherical toner remaining on the image carrier on which the visible image is transferred by the transfer device reaches the pressing portion of the cleaning blade. In order that the irregular toner has already reached and existed at the pressing portion, the irregular toner is adhered onto the image carrier by using a black image developing device containing the irregular toner. An image forming apparatus comprising Rukoto. 2. A developing device for developing a latent image on an image carrier,
A transfer device that transfers the visible image on the image carrier to a transfer material, and a cleaning device that presses a cleaning blade against the surface of the image carrier to remove the toner remaining on the surface of the image carrier to which the visible image has been transferred. An image forming apparatus including a developing device, a developing device containing a spherical toner, and an irregular shape developing device.
Constituted by a developing unit containing a toner, a developing device in which the development of the tip portion of the image bearing member surface movement direction of the image area on the image carrier by the developing device accommodating the irregular toner, accommodating the spherical toner An image forming apparatus, wherein the portion of the image area other than the front end portion is developed. 3. A developing device containing the irregular toner in a non-image region on the leading end side of the image region in the moving direction of the surface of the image carrier prior to the development of the image region by the developing device containing the spherical toner. 3. The image forming apparatus according to claim 1, wherein the image forming apparatus develops. 4. The spherical toner reaching the pressing portion of the cleaning blade from the rear of the developing area of the irregular toner by the width of the developing area of the irregular toner in the direction orthogonal to the moving direction of the surface of the image carrier. The image forming apparatus according to claim 1, wherein the width is set to be equal to or larger than the width of the developing area in the orthogonal direction. 5. A control means is provided for controlling whether or not the amorphous toner is attached to the non-image area based on whether or not the image area on the image carrier is developed with only the amorphous toner. The image forming apparatus according to claim 3, wherein the image forming apparatus comprises: 6. The amount of spherical toner on the image carrier that reaches the cleaning device is calculated, and the amount of irregular toner on the image carrier that reaches the cleaning device is changed according to the calculation result. 4. The image forming apparatus according to claim 3, further comprising control means for controlling setting of conditions for forming a visible image by the irregular toner on the image carrier. 7. The amount of spherical toner on the image carrier that reaches the cleaning device is determined based on the number of pixels of the latent image to be developed with the spherical toner or the writing light amount of each pixel and the transfer condition of the transfer device. The image forming apparatus according to claim 6, which is calculated. 8. The write data obtained by compressing the latent image developed with the spherical toner in the moving direction of the surface of the image carrier is used as the write data for the latent image developed with the irregular toner. 7 image forming apparatus. 9. A developing capacity detecting means for detecting a developing capacity of a developing device containing the irregular toner, and a latent image forming condition for developing with the irregular toner based on a detection result of the developing capacity detecting means. 7. The image forming apparatus according to claim 6, further comprising a control unit that changes the setting of. 10. An arrival amount of the irregular toner on the image carrier to the cleaning device per unit time and an arrival amount of the spherical toner on the image carrier to the cleaning device per unit time. 7. The image forming method according to claim 6, wherein a condition for forming a visible image with the irregular toner is set such that the sum is less than the maximum arrival amount of the irregular toner that can be cleaned by the cleaning device. apparatus. 11. A developing device for developing a latent image on an image carrier, a transfer device for transferring a visible image on the image carrier to a transfer material, and a cleaning blade pressing the surface of the image carrier. A cleaning device for removing the toner remaining on the surface of the image carrier onto which the visible image has been transferred, an intermediate transfer member to which the visible image on the image carrier is transferred, and the visible image to the intermediate transfer member. The first transfer means, the second transfer means for transferring the visible image on the intermediate transfer body to the transfer material by bringing the intermediate transfer body and the transfer material into close contact with the transfer member, and the cleaning blade for the intermediate transfer. An intermediate transfer member cleaning device for removing the toner remaining on the surface of the intermediate transfer member, which has been transferred to the transfer material by pressing the visible image on the body surface, and the transfer by pressing a cleaning blade on the surface of the transfer member. Residue on member surface An image forming apparatus including a transfer member cleaning device for removing toner, the developing device including a developing device containing spherical toner and a developing device containing irregular toner, and containing the spherical toner. Prior to development by the developing device,
A visible image is formed on the image bearing member by development by a developing device containing the irregular toner, and a part of the visible image of the irregular toner on the image bearing member is transferred to the intermediate transfer member, and the intermediate transfer is performed. An image forming apparatus, which transfers a part of a visible image of amorphous toner on a body to the transfer member. 12. A developing device for developing a latent image on an image carrier, a transfer device for transferring a visible image on the image carrier to a transfer material, and a cleaning blade pressed against the surface of the image carrier. A cleaning device for removing the toner remaining on the surface of the image carrier onto which the visible image has been transferred, an intermediate transfer member to which the visible image on the image carrier is transferred, and the visible image to the intermediate transfer member. The first transfer means, the second transfer means for transferring the visible image on the intermediate transfer body to the transfer material by bringing the intermediate transfer body and the transfer material into close contact with the transfer member, and the cleaning blade for the intermediate transfer. An intermediate transfer member cleaning device for removing the toner remaining on the surface of the intermediate transfer member, which has been transferred to the transfer material by pressing the visible image on the body surface, and the transfer by pressing a cleaning blade on the surface of the transfer member. Residue on member surface And a transfer member cleaning device for removing toner, the developing device is composed of a plurality of developing devices respectively containing toners of different colors, and at least one of the plurality of developing devices is provided. The toner contained in the developing device is an irregular toner, the toner contained in the other developing devices is a spherical toner, and prior to the development by the developing device containing the spherical toner,
A visible image is formed on the image bearing member by development by a developing device containing the irregular toner, and a part of the visible image of the irregular toner on the image bearing member is transferred to the intermediate transfer member, and the intermediate transfer is performed. An image forming apparatus, which transfers a part of a visible image of amorphous toner on a body to the transfer member. 13. A single visible image is formed on an image carrier by development with a developing device containing the irregular toner, and the developed image is distributed to the image carrier, the intermediate transfer member and the transfer member. 13. The image forming apparatus according to claim 11, wherein the transfer conditions in the first transfer unit and the second transfer unit are set so as to achieve the above. 14. A plurality of visible images on the image carrier formed on the image carrier by development by a developing device containing the irregular toner are transferred to the image carrier, the intermediate transfer member and the transfer member. 13. The image forming apparatus according to claim 11, wherein the transfer conditions in the first transfer unit and the second transfer unit are set so as to be distributed. 15. The amount of spherical toner on the image bearing member, the intermediate transfer member and the transfer member reaching each cleaning device is calculated, and the image bearing member reaching each cleaning device is calculated according to the calculation result. Body, the condition for forming a visible image by the irregular toner on the image carrier so as to change the amounts of the irregular toner on the intermediate transfer member and the transfer member, and the first
15. The image forming apparatus according to claim 11, 12, 13 or 14, further comprising: a transfer unit for controlling the transfer condition and a control unit for controlling setting of transfer conditions in the second transfer unit.