JPH07191586A - Image forming device - Google Patents

Abstract

PURPOSE:To obtain a pseudo black image through the use of recovered toner to be discarded by recovering each color toner remaining on a photoreceptor after a transfer process and using the recovered toner as a developer. CONSTITUTION:As a copying action for a multicolor copying machine, a normal mode using each color toner of yellow, magenta, cyan and black and a recycling mode using a toner mixture in a recycling /developing unit are used, each color toner after being used in development is made clean by a cleaning device 8 and passes through a toner carrying pipe 76, to be carried to a developing device 75. As the copying action in the recycling mode, only the developing device 75 is actuated to form an image when an operator selects the recycling mode. When the development is attained by using a four color toner mixture housed in the developing device 75, the pseudo black image can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multicolor image forming apparatus such as a multicolor copying machine or a multicolor printer having a toner recycling device.

[0002]

2. Description of the Related Art Conventionally, a multi-color image forming apparatus has a waste toner box for collecting the toner remaining on the photoconductor by a cleaning device after the transfer process and storing the toner.

[0003]

However, the color toner is more expensive than the conventional black toner, and it is uneconomical to discard this expensive toner. Further, a waste toner box has to be installed in the image forming apparatus, which causes an inconvenience that the image forming apparatus becomes large.

On the other hand, it is conceivable that the toner remaining on the photoconductor after the transfer step is recycled to each color developing device which accommodates the developer of the same color according to the color of each residual toner, but in this case, it remains on the photoconductor. Toners must be collected for each color without being mixed, and a transporting path for transporting to each color developing device is required for each number of colors, so that a considerably large-scale recycling device is required as an image forming device, which is a realistic problem. Not a thing.

[0005]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and collects each color toner remaining on a photoconductor after a transfer process in an image forming apparatus, and at the same time, collects each color toner. By installing a developing device for accommodating the recovered toner as a developer, if the operator does not pay much attention to the color to be copied, a pseudo black image can be obtained by selecting the use of the developing device.

[0006]

In the image forming apparatus described above, a pseudo black image can be obtained by a developing device that collects each color toner remaining on the photoconductor after the transfer process and stores the collected toner as a developer.

[0007]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows a schematic structure of a multicolor copying machine. A photoconductor 1 is an endless belt having a photoconductor layer on its outer peripheral surface and wound around a roller 3 equipped with a rotation detection sensor 2 and rollers 4 and 5. The roller 3 is rotated to move in the direction of arrow a based on the rotation of the roller 3, and a charging charger 6, a developing device 7, a cleaning device 8 and an eraser lamp 9 are arranged around the periphery. The developing device 7 includes five developing devices 71, 7
2, 73, 74, and 75, and the developing device 71,
72, 73, and 74 are yellow, magenta, cyan, and black color developers, and the developing device 75 is a cleaning device 8.
A recycled developer that reuses the four-color mixed toner collected by is stored, and can be switched between a developing state and a non-developing state. The cleaning device 8
The recycle color developing device 75 and the recycle color developing device 75 are connected by a toner carrying pipe 76, and the toner collected by the cleaning device 8 is carried to the recycle color developing device 75 by rotating a carrying means (not shown) inside the carrying pipe. To be done.

The image reading device 10 has an opening / closing cover 11 on the upper side.
It is placed below the platen glass 12 covered with
A document illumination lamp 13 illuminates a document (not shown) placed on the platen glass 12 and moves in the direction of arrow b. In addition, the reflected light from the document is reflected by the mirror system 14.
The line sensor 16 reads the color signals of the three primary colors through the lens system 15, and the signals of the respective colors are read by the image processing circuit 17.
It is designed to be output to.

The image exposure device 18 is provided with a laser emission device 19, emits a laser beam 20 based on the output from the image processing circuit 17, and emits the laser beam 20 between the charger 6 and the developing device 7. The outer peripheral surface of the photoconductor 1 is exposed.

The transfer belt 21, which is a rotary transfer member, is wound around a drive roller 22 and a driven roller 23 disposed below the drive roller 22, and the belt tension can be adjusted by a tension roller 24. Inside the transfer belt 21, a transfer roller 25 is disposed so as to be capable of advancing and retreating toward the drive roller 22, and the transfer belt 25 is brought into contact with and separated from the photoconductor 1 by the transfer roller 25. ing. Further, inside the transfer belt 21, sheet detection sensors 26, 27, and 28 are provided near the tension roller 24 and above and below the transfer roller 25, respectively. Below the transfer roller 25, a pair of assist rollers 29 for bringing the sheet into close contact with the outer peripheral surface of the transfer belt 21 is provided. The driven roller 2 is provided outside the transfer belt 21.
Belt cleaner 3 facing the belt wound around 3
0 and a charging charger 31, a charge eliminating charger 32 facing the belt portion passing through the facing portion of the photoconductor 1, and a separating claw 33 contacting and separating the belt portion wound around the driving roller 22.

The paper feeding device 34 includes three paper feeding units 35, 36,
37, the sheets accommodated in the sheet feeding units 35, 36, and 37 are selectively supplied, and the transfer belt is synchronized with the toner image formed on the photoconductor 1 by the timing roller 38. 21 is supplied.

The fixing device 39 and the discharge roller 40 are arranged above the transfer belt 21, and the sheet passing through the fixing device 39 is discharged to the discharge tray 41 by the discharge roller 40.

The copying operation of the multicolor copying machine is divided into a normal mode using yellow, magenta, cyan, and black toners and a recycling mode using mixed toner in a recycling developing device.

The multicolor copying operation in the normal mode of the multicolor copying machine will be briefly described. Copy manuscript (not shown)
Is placed on the platen glass 12, and a document cover 11 is placed over it. Next, when a print switch (not shown) is turned on, in the image reading apparatus 10, the document illumination lamp 13 illuminates the document while moving in the direction of arrow b, and the reflected light thereof causes the mirror system 14 and the lens system 15 to illuminate. It is incident on the line sensor 16 via the line sensor 16 and is read by the line sensor 16 as color signals of three primary colors. The color signal is converted into a four-valued signal of yellow, magenta, cyan, and black by the image processing circuit 17, and the output signal is output to the image exposure device 18.

The image exposure device 18 first emits the laser light 20 corresponding to the yellow image based on the above output signal, and when it finishes, emits the laser light 20 corresponding to the magenta image. When finished, the laser beam 20 corresponding to the cyan image is emitted, and finally the laser beam 20 corresponding to the black image is emitted. The emission timing of each laser beam 20 will be described later.

The photoconductor 1 moves in the direction of the arrow a based on the rotation of the roller 3, and a charge of a predetermined potential is applied to the outer photoconductor layer at the portion facing the charging charger 6 to be charged. The charged photoreceptor 1 is irradiated with the laser light 20 emitted from the image exposure device 18, and electrostatic latent images of different colors are sequentially formed on the outer peripheral surface. The electrostatic latent images of the respective colors are then visualized as toner images by the developing devices 71, 72, 73 and 74 having the developers of the corresponding colors. The rotation detection sensor 2 detects the rotation of the photoconductor 1 by a pulse signal generated every one rotation of the roller 3, and the laser light 20 is emitted from the image exposure device 18 at a timing from the pulse signal. .

The transfer belt 21 moves in the direction of arrow c based on the rotation of the driving roller 22 started by the ON signal of the print switch, and after the surface is cleaned by the belt cleaner 30, it is charged to a predetermined potential by the charging charger 31. To be done. On the other hand, the sheet sent out from the paper feeding section 35, 36 or 37 is temporarily stopped at the position of the timing roller 38 and electrostatically adhered to the outer peripheral surface of the transfer belt 21 in time with the toner image formed on the photoconductor 1. Adsorbed,
It is reliably held by passing between the pair of assist rollers 29.

The sheet held on the transfer belt 21 is conveyed in the direction of arrow c as the transfer belt 21 moves,
When the sensor 28 detects the leading edge of the sheet, the transfer roller 25 moves to the right side in the figure and comes into contact with the photoconductor 1. Then, while the sheet is nipped and conveyed between the transfer roller 25 and the photoconductor 1, a yellow toner image is transferred at a contact position between the transfer roller 25 and the photoconductor 1 (hereinafter referred to as a transfer position 42). The sheet onto which the yellow toner image has been transferred is then repeatedly conveyed to the transfer position 42 with the magenta, cyan, and black toner images, respectively, and these toner images are superimposed.

With respect to the sheet on which the toner images of all colors have been transferred, the electrostatic attraction force of the sheet to the transfer belt 21 is weakened by the charge removal charger 32, and the sheet is separated from the transfer belt 21 by the separating claw 33, and the toner is fixed by the fixing device 39. After the image is heated and fixed, the paper is ejected by the paper ejection roller 40 to the paper ejection tray 41.
Is discharged to. On the other hand, the outer peripheral surface of the photoconductor 1 from which the toner image is deprived at the transfer position 42 is cleaned by the cleaning device 8, and then the residual charge is erased by the eraser lamp 9. At this time, the toner cleaned by the cleaning device 8 is transported to the developing device 75 through the toner transport pipe 76.

In the copying operation of the multicolor copying machine in the recycling mode, when the operator selects the recycling mode from the operating panel (not shown) of the copying machine, only the developing device 75 is operated to form an image. Become. FIG. 2 shows another embodiment 71, 72, 7 of the present invention.
Reference numerals 3 and 74 are developing devices having yellow, magenta, cyan, and black toners, respectively, and 77 is a magnetic brush developing device that also serves as a cleaner. Figure 1 shows the development of each color.
The cleaning process for each color is performed by the magnetic brush developing device 77 which also serves as a cleaner, as described in the above. 3 and 4 are enlarged views of a main part of the magnetic brush developing device 77 that also serves as a cleaner, and 84 is a developer mixing member, 78.
Is a magnetic brush roller whose bias voltages V1 and V2 can be switched by a switch S, and 80 is a toner collecting roller. When the operator selects the recycle mode from the operation panel of the copying machine, the developing device 77 operates. As shown in FIG. 3, a bias voltage V2 is applied to the magnetic brush roller 78, and the latent image on the photoconductor 1 is developed by the color mixture toner stored in the developing device 77. Further, as shown in FIG. 4, when the cleaner / magnetic brush developing device 77 is used as a cleaner, the magnetic brush roller 78 is applied with a bias voltage V1 in the direction of collecting the residual toner 83 on the photoconductor 1. The residual toner can be cleaned.

[0022]

As is apparent from the above description, according to the image forming apparatus of the present invention, it is possible to reuse the residual toner which has been conventionally discarded as a developer and to provide the waste toner box. There is no need.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a schematic configuration of a multicolor copying machine.

FIG. 2 is a cross-sectional view showing a schematic configuration of a multicolor copying machine including a magnetic brush developing device that also serves as a cleaner.

FIG. 3 is an explanatory cross-sectional view showing a state of a magnetic brush developing device that also serves as a cleaner during development.

FIG. 4 is a cross-sectional explanatory view showing a state at the time of cleaning the magnetic brush developing device that also serves as a cleaner.

[Explanation of symbols]

1 ... Photoconductor, 7 ... Developing device, 71, 72, 73, 74 ...
Yellow, magenta, cyan, black color developing device, 75
... Recycled color developing device, 76 ... Waste toner carrying pipe, 7
7 ... Magnetic brush developing device that also functions as a cleaner, 21 ... Transfer belt (transfer body)

Front page continuation (72) Inventor, Koichi Sano 2-3-13 Azuchi-cho, Chuo-ku, Osaka, Osaka International Building Minolta Camera Co., Ltd. (72) Inventor Masahiko Matsuura 2-3-3, Azuchi-cho, Chuo-ku, Osaka No. Osaka International Building Minolta Camera Co., Ltd. (72) Inventor Hiroyuki Yamazaki 2-33 Azuchi-cho, Chuo-ku, Osaka Osaka International Building Minolta Camera Co., Ltd. (72) Inventor Atsuto Makai Azuchi, Chuo-ku, Osaka 2-13-3 Machi Osaka International Building Minolta Camera Co., Ltd. (72) Inventor Masami Yamada 2-33 Azuchi-cho, Chuo-ku, Osaka City Osaka International Building Minolta Camera Co. (72) Inventor Fumio Masuda Minato Camera Co., Ltd., Osaka International Building 2-33 Azuchicho, Chuo-ku, Osaka

Claims (1)

[Claims] 1. A toner of each color collected by a plurality of developing devices for storing yellow, magenta, cyan, and each color developer and a cleaning device for collecting each color of toner remaining on the photoconductor after the transfer process. An image forming apparatus, comprising: a developing device that stores a developer having a mixed toner.