JPS5931071B2 - developing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a developing device for an electrophotographic copying machine, and particularly to a developing device that can be optimally used for dry multicolor development.

2. Description of the Related Art Conventionally, in a developing device that supplies a dry type developer, one that is configured to suck air around a developing section has been proposed in order to prevent the toner from scattering.

This was particularly preferred in order to prevent color mixing between developing devices when performing multi-color development (FIG. 1). However, in order to achieve good suction, the device has to be large-sized.
Furthermore, when the developing device is moved closer to the photoreceptor in order to increase the suction efficiency, toner from the developing device when not in operation is supplied to the photoreceptor, potentially causing unnecessary development or color mixing. In view of the above points, the present invention provides a developing device that enables good development.

Briefly, the apparatus of the present invention includes a developing means that is supported to be able to approach and separate from an image carrier, and a suction means that has a suction opening adjacent to the developing means, and which allows the developing means to approach the image carrier. The suction means are operated in synchronization with each other.

The details of the present invention will be explained below using specific examples with reference to the drawings.

FIG. 2 is a schematic diagram illustrating a developing device according to the present invention, and numeral 1 denotes an image carrier, such as a photoreceptor, which carries an electrostatic image to be developed.

2 is a developing device, and 2, 22, 23 are movable developing units that provide different color developers.

31 to 34 are suction ducts, 5 is a dividing plate having openings 51, 52, and 53 that are opened and closed at the bottom of the developing unit, 1 is a dust collector, 41 is a dust collection filter, and 42 is a suction fan.

FIG. 2 shows the operating state of the developing device, in which the developing unit 22 moves to a position close to the image carrier and supplies developer to the surface of the image carrier.

On the other hand, due to the movement of this developing unit, the opening 52 of the dividing plate 5
is opened, the air sucked through the suction ducts 32 and 33 passes through the filter 4, and the suction fan 42
released. 2, when the developing device is not in operation, each developing unit is located away from the image carrier, and the bottom of each unit closes each opening of the dividing plate 5, and the suction No action is taken. In this way, a predetermined developing unit starts its suction operation at the same time as it moves to the operating position, and the developer from the operating developing unit does not scatter into the machine or into an adjacent developing unit. Moreover, since the suction operation is performed only around the predetermined developing unit, better suction efficiency can be achieved than when suction is performed from all around each unit. FIG. 3 is a side view of a specific example color copying machine to which the apparatus of the present invention is applied.

The original image placed on the document table 6 is illuminated by the illumination means 7, and the illuminated image is scanned by mirrors Ml and m2 that move and scan at a speed ratio of 2:1, and is scanned by the optical system 8 and the color separation filter 19. The mirrors M3 and m4 are passed through a predetermined color separation filter (for example, a red filter) as a predetermined color separation image.
The image is then projected onto the photoreceptor. In the illustrated example, a photoreceptor having an insulating layer provided on its surface is used, which is uniformly charged in advance by a charger 10, and simultaneously with the light image exposure, reverse polarity charging or AC charge removal is performed by the charger 11, and then a light source is applied. 12, the entire surface is exposed to form a high contrast electrostatic latent image. The electrostatic latent image is developed in a predetermined color developing unit (for example, a cyan color developing unit) of the developing device configured as described above.

The developed image is supplied from the force set 14 and transferred onto the transfer material P held on the transfer device 13. The surface of the photoreceptor after the transfer is cleaned by a cleaning device 15. Predetermined color separation images are sequentially formed on the photoreceptor, developed with corresponding color developers, and transferred onto the transfer material P in a superimposed manner. After a predetermined number of transfers, the transfer material P is separated from the transfer device 13 and transferred to the fixing device 16.
After fixing, the paper is discharged onto the paper discharge tray 17. FIG. 4 shows details of a mechanism for moving each developing unit of the developing device of the illustrated copying machine.

A vertically movable cam 206 provided in each unit 21 to 24 is attached to a rotating shaft 208.

A gear 203 provided on the rotating shaft 208 and gears 2011 and 2021 connected to a pair of electromagnetic clutches 201 and 202.
A chain 204 is stretched between the gears 2012 and 2 on the opposite side of the electromagnetic clutches 201 and 202.
A chain 205 is spanned over 022 so as to be interlocked with the motor M2 for vertical movement of the developing device. In the above configuration, a pair of electromagnetic clutches rotates the chain 205, which is connected to each gear of the clutches, in mutually opposite directions. Therefore, as shown in the figure, the first
When the electromagnetic clutch 201 is turned on, the chain 204 is driven as shown by the solid arrow, the vertical movement cam 206 is rotated clockwise, and the developing unit 2 is raised. When the developing unit 21 rises to a predetermined position, the electromagnetic clutch 201 is turned off and stopped by an off signal detected by, for example, a micro switch MSl provided to detect this position. On the other hand, when the development is completed and the development unit 21 is to be lowered, the second electromagnetic clutch 202 is turned on.

At this time, the chain 204 is driven as indicated by the dashed arrow, rotating the vertically movable cam counterclockwise and lowering the developing unit. When the developing unit is lowered to a predetermined position, an off signal detected by a micro switch provided to detect this position turns off the second electromagnetic clutch 202 to stop it.

Each developing unit sequentially ascends and descends as described above to develop electrostatic latent images of predetermined colors on the image carrier 1. In the above-described upward and downward movements, the developing unit 21 is supported by the parallel link mechanism 207 and is therefore moved without being tilted.

Therefore, there is no risk of the developer spilling and contaminating the inside of the machine. Further, openings 51 to 53 communicating with the dust collector 4 are connected to the developing unit 2.
It can be completely blocked at the bottom of 1 to 23. if,
If the developing unit tilts and stops at the lowered position during movement, the opening cannot be completely blocked.

If this happens, the suction efficiency around the other working developing units will be reduced, and the efficiency of collecting the scattered developer around the working developing units will be poor, causing internal contamination or color mixing. On the other hand, such inconveniences can be effectively eliminated by moving not only the link mechanism but also the device of the present invention.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram illustrating the configuration of a conventional device. 2 are schematic diagrams illustrating the configuration of the apparatus of the present invention, with FIG. 2 1 illustrating an operating state and FIG. 2 2 illustrating a non-operating state. FIG. 3 is a side view of an embodiment of a color copying machine to which an apparatus based on the present invention is applied. FIG. 4 is a partial perspective view illustrating the moving mechanism of the substrate example developing device. In the figure, 1 is a photoreceptor, 2 is a developing device, 21, 22, 23 is a developing unit, 31, 32, 33, 34 is a suction duct, 4
4 is a dust collector, 41 is a dust collection filter, and 42 is a suction fan.

Claims (1)

[Scope of Claims] 1. An image carrier carrying a latent image; a plurality of developing units provided in the moving direction of the image carrier to develop the latent image on the image carrier; The image bearing member is provided with a driving means for individually moving toward and away from the body, a common suction means, and suction openings provided corresponding to each of the developing units connected to the suction means, and Only the moved developing unit opens the suction opening, and the developing unit that is not moved closes the suction opening by itself, and has a suction duct in which suction air acts on the opened unit by the opened suction opening. A developing device characterized by: